Recent advances in Resource and Energy Conservation

Responsible Fishing: Recent advances in Resource and Energy Conservation

Editors

Leela Edwin, Saly N. Thomas, M.P. Remesan, P. Muhamed Ashraf, M.V. Baiju, Manju Lekshmi N., Madhu V. R.

ICAR-Central Institute of Fisheries Technology (Indian Council of Agricultural Research)

CIFT Junction, Matsyapuri P.O., Cochin – 682 029

2019

Responsible Fishing: Recent advances in Resource and Energy Conservation

Leela Edwin, Saly N. Thomas, M.P. Remesan, P. Muhamed Ashraf, M.V. Baiju, Manju Lekshmi N., Madhu V. R. ICAR- Central Institute of Fisheries Technology, CIFT Junction, Matsyapuri P.O., Cochin – 682 029, India. Phone : 91 (0) 484 - 2412300 FAX: 91 (0) 484 – 2668212 Email: [email protected] November 2019 Published by : Dr. Ravishankar C.N. Director,

ICAR – Central Institute of Fisheries Technology, Cochin

Printers: PrintExpress, Cochin – 682 017

mailto:[email protected]

Contents Sl. No. Title Page No.

1. Foreword i

2. Preface ii

3. Current status of Biodiversity, its Conservation and Sustainable Development

1

4. Recent advancements in fish harvest sector by ICAR-CIFT 9

5. Marine fisheries in India 19

6. Status of Inland Fishery Resources of India 23

7. FAO Code of Conduct for Responsible Fisheries - Fishing Operations 41

8. Netting Materials for Fishing Gear with Special Reference to Resource Conservation and Energy Saving

55

9. Classification of Fishery Vessel types 71

10. Boat Building Materials with Special Reference to Environmental Impacts

87

11. Basic Principles of Design of Fishing Gears and their Classification 95

12. Novel Extension Approaches for Sustainable Technology Dissemination in Fisheries

119

13. Small Scale Fisheries Guidelines from the resource and energy conservation perspective

135

14. Energy Efficient Fishing Vessels and use of Alternate Energy for Fishing

143

15. Basics of Designing of Fishing Vessels 151

16. Energy use in fishing 159

17. LCA Analysis: Case Study of Ring Seine Fishing Systems of Kerala 167

18. Energy Efficient and Resource Friendly Trawl Systems 177

19. Bycatch Reduction Devices for Trawls 187

20. Fishing Technology interventions for sea Turtle conservation 197

21. Surrounding nets and seines: structure, operation and conservation aspects

213

22. Diversity of trawl catch in India 231

23. Sustainable Gillnet Fishing 239

24. Gillnet fishing in Reservoirs: Problems and Solutions 251

25. Design, Operation of Long lines for Resource and Energy Conservation

261

26. Strategies for Material Protection in Aquatic Environment 287

27. Environmental impact assessment of chemical protectants used in fishing industry

293

28. Resource Conservation in Estuarine Set Bag Net Fishery 303

29. Dol Net Fishery of India: Need for Resource Conservation 313

30. Design, construction and operation of fishing pots and traps 319

31. Onboard Handling and Processing of Tuna 327

32. Quality and Safety Requirements for Fishing Harbours and Landing Centers

339

33. Resource and Energy Conservation through Hook and Line Fishing 355

34. Importance of Fish Behaviour Studies in Fishing Gear Design 369

35. Sustainable Fishing Methods for Inland Water Bodies 377

36. Engineering Tools and Technologies for Energy Efficient Fish Processing Operations

391

37. Policies and Regulations for Marine Fisheries Conservation and Management in India

405

38. Marine Electronic Equipment used in Fishing Vessels 411

i

Foreword The global fish production reached the all-time high in 2016, estimated at 171 million tonnes, with the capture fishery from marine and inland waters, contributing 90.9 million tonnes. With this highest recorded production, the world fish supply reached 20.3 kg per capita in 2016. The record growth has been due to the increase in aquaculture production, whereas the global marine fisheries production has reached a plateau during the last decade and is now hovering around 80 million tonnes. The total fish production in India during the year 2016-17 was 11.41 million tonnes, with a contribution of 7.77 million tonnes from the Inland sector and 3.64 million tonnes from the marine sector. The country has 194,490 crafts in the marine fishery, out of which 37% are mechanized, 37% motorized and 26% non-motorized. The capture fishery in Indian has been in a state of no-growth and any further expansion is possible only by targeting hitherto less targeted oceanic species like tunas and billfishes, for which efforts are on. Over exploitation, and habitat degradation has been the major causes for the stagnation of catches from the inland sector, whereas the marine fisheries sector of India, is facing a myriad of issues that include over exploitation, climate change issues, high-energy inputs and social issues for over more than a decade. Consequently, to the developments in the fishing sector, the priority of research in fishing technology now is towards conservation and development of fishing gears and methods, that least affect the fish stocks, habitats and ecosystem with least energy expended. ICAR-Central Institute of Fisheries Technology for the last six decades has been engaged in research and development of resource and energy efficient harvesting systems for inland, aquaculture and marine sectors of the country. The ICAR winter school on “Responsible Fishing: Recent Advances in Resource and Energy Conservation” is an attempt towards disseminating the technologies and methodologies developed by the institute to teachers, researchers, subject matter specialists and extension personnel engaged in the field of fisheries. The compilation of chapters in this book, which caters to the theme of the winter school, will be beneficial to the participants as a basic reference material. I hope the participants will take full advantage of the lectures by eminent scientists in the field for which this book will be an added benefit.

Dr. Ravishankar C.N. Director

Cochin – 682 029 19 November 2019

ii

Preface

The emphasis of Indian fisheries is focused towards responsible harvesting through energy efficient and eco-friendly fishing systems with minimum collateral damage. The ICAR winter school on “Responsible Fishing: Recent Advances in Resource and Energy Conservation” was taken up the ICAR-Central Institute of Fisheries Technology to update researchers, teachers and extension personnel who are the major stakeholders in this sector regarding the latest development in the field of fishing technology. This book on “Responsible Fishing: Recent Advances in Resource and Energy Conservation”, is a compilation of edited lecture notes of the winter school covering the entire gamut of fishing technology ranging from the fishery resources, fish harvesting systems, policy issues and with great emphasis on resource and energy conservation techniques. The articles compiled in this book, are prepared by experts in their respective fields and given emphasis to the present scenario in the fishing technology in the Country and illuminate concrete steps for way forward. Due attention is given to highlight the basic concepts of fishing technology for novices in the field as well as recent developments for experts to understand the present status and come up with solutions to the different problems that are highlighted in the lecture notes. The publication will be a valuable guide to all stakeholders in the fish harvesting and allied sectors.

Dr. Leela Edwin Director (Winter School)

Cochin – 682 029 19 November 2019

1

ICAR Winter School: Responsible Fishing: Recent Advances in Resource and Energy Conservation 21 November – 11 December 2019, ICAR-CIFT, Kochi

Current status of Biodiversity, its Conservation and Sustainable Development

B. Meenakumari Formerly, Chairperson, National Biodiversity Authority, Chennai

E-mail: [email protected]

India - A land of Major Biomes1

Biological diversity is the web of life - it’s the resource upon which all life depends. India is one of the 17 mega-biodiverse countries of the world covering an area of 329 million hectares which is 2.4 % of world’s land area. The country accounts for nearly 7-8% of world’s recorded species which includes over 47,000 species of plants and 92,000 species of animals in ten bio-geographic regions. India is also rich in traditional and indigenous knowledge, coded as in ancient Indian Systems of Medicines and also informal, as it exists in oral traditions and folklore.

Geographically, India is the seventh largest country in the world and Asia's second largest nation. Physically this massive country is divided into four relatively well defined regions - the Himalayan mountains, the Gangetic river plains, the southern (Deccan) plateau, and the islands of Lakshadweep, Andaman and Nicobar. The agriculturally productive alluvial silts and clays of the Ganga-Brahmaputra delta in north-eastern India, for example, contrast strongly with the comparatively sterile sands of the Thar Desert which is located at the western extremity of the Indian part of the plains in the state of Rajasthan. The climate of India is dominated by the Asiatic monsoon, most importantly by rains from the south-west between June and October, and drier winds from the north between December and February. From March to May the climate is dry and hot.

From the biodiversity standpoint, India has some 59,353 insect species, 2,546 fish species,

240 amphibian species, 460 reptile species, 1,232 bird species and 397 mammal species, of which 18.4 per cent are endemic and 10.8 per cent are threatened. The country is home to at least 18,664 species of vascular plants, of which 26.8 per cent are endemic. It has been estimated that at least 10 per cent of the country’s recorded wild flora, and possibly the same percentage of its wild fauna, are on the threatened list, many of them on the verge of extinction. Nearly 6,500 native plants are still used prominently in the indigenous healthcare systems.

1a complex biotic community characterized by distinctive plant and animal species and maintained under the climatic conditions of the region, especially such a community that has developed to climax.

2


Biogeographic Classification:

India also has a rich cultural heritage going back thousands of years. Much of Indian biodiversity is intricately related to the socio-cultural practices of the land. Unfortunately, due to population explosion, climate change and lax implementation of environmental policies, several species are facing the threat of extinction. Not only does this affect the food chain, but also the livelihood and the culture of millions of Indians who depend on local biodiversity. India’s vast demographic diversity is both good and bad for its biodiversity. Good for biodiversity because this human diversity has resulted in a plethora of customs, traditions and rituals in the context of native species. Plants and animals are considered sacred, find mentions in mythological stories and are used in religious rituals. Bad because of the enormous pressure the human population puts on the natural resources. These deep associations between biodiversity and culture present us with a unique opportunity for their conservation. Important Conservation Sites in India (as on July, 2017):

Reserves/ Sites Numbers Total area

(in Sq.Kms.) Tiger Reserves 50 71027.10 Elephant Reserves 32 69,582.80 Biosphere Reserves 18 87491.6 RAMSAR Wetland Sites 26 12119.03 Natural World Heritage Sites 07 11755.84 Cultural World Heritage Sites 27 -- Mixed World Heritage Sites 01 1784.00

3


Important Coastal and Marine Biodiversity Areas

107 10773.07

Marine Protected Areas 131 9801.13 Important Bird Areas 467 -- Potential Important Bird Areas 96 -- Key Biodiversity Areas 531 -- Biodiversity Heritage Sites 9 --

Source: http://www.wiienvis.nic.in/Database/ConservationAreas_844.aspx

Four of the 34 globally identified biodiversity hotspots, namely the Himalaya, Indo-Burma, the Western Ghats-Sri Lanka and Sundaland are in India. The key criteria for determining a hotspot are endemism (the presence of species found nowhere else on earth) and degree of threat (Conservation International, 2013).

i. The Himalaya: Western and Eastern Himalaya form part of Himalayan global biodiversity

hotspot.

ii. The Western Ghats: Part of Western Ghats-Srilanka global biodiversity hotspot.

iii. North-East: Part of Indo-Burma global biodiversity hotspot.

iv. Nicobar Islands: Part of the Sundaland global biodiversity hotspot

Global Biodiversity Hotspots:

Source: Conservation International: www.conservation.org; www.cepf.net

4


Total number of plant species (including virus, bacteria, algae, fungi and lichens) and their status in World and India

SI. No.

Type Number of known Species

Percentage of Occurrence in India

Number of Endemic Species

Number of Threatened Species World India

I 1. 2.

Flowering Plants Gymnosperms Angiosperms

1021 268600

74 18043

7.35% 6.72%

8 ca. 4036

7 1700

II 1. 2.

Non-flowering Plants Bryophytes Pteridophytes

16236 12000

2523 1267

15.54% 10.57%

629 47

ca. 80 414

III 1. 2. 3. 4.

Others Virus and Bacteria Algae Fungi Lichens

11813 40000 98998 17000

986 7284 14883 2401

8.77% 18.21% 15.09% 14.12%

Not Known 1924 ca. 4100 ca. 520

Not known Not known ca. 580 Not known

Total

465668

47513

–

11273

2781

Source: http://www.bsienvis.nic.in/Database/Status_of_Plant_Diversity_in_India_17566.aspx Faunal Species Richness and Endemism

India has a very rich range of faunal diversity, which is still far from completely

documented. Nearly 92,000 species of fauna have been reported from India, a little over 7% of the world's reported animal diversity. There is considerable variation in the representation of different phyla and subphyla, with the percentage of species in India varyingfrom as low as 1% (Sipuncula) to as high as about 40% (Echiura). However, much of this variation is due to several minor phyla and subphyla, which are primarily marine, and might reflect inadequate species documentation rather than real differences. Among the more speciose phyla or lower taxa, India has between 4 and 12% of the global species.

Diversity of Fauna in India and the World: Faunal diversity in India (Group)

World (number of species)

India (number of species)

(%) in India

Mammals 4629 397 8.58 Birds 8,400 458 5.45 Reptiles 5817 460 7.91 Amphibians 5150 248 4.81 Fishes 23,400 5749 24.56 Insects 867391 61151 7.04 Molluscs 66535 5072 7.62

Source: National Biodiversity Action Plan, 2008

5


Convention on Biological Diversity (CBD)2

The United Nation’s Convention on Biological Diversity (CBD), that was adopted during the Earth Summit held on June 5, 1992 at Rio de Janeiro was the first comprehensive global agreement addressing all aspects relating to biodiversity. In pursuance to the CBD, India enacted the Biological Diversity (BD) Act in 2002, and notified the Rules in 2004, through an extensive consultative process initiated in 1994. India was one of the first few countries to have enacted such a comprehensive legislation on biodiversity. The BD Act mandates its implementation through a decentralized system with National Biodiversity Authority at national level, the State Biodiversity Boards (SBBs) at the State level and Biodiversity Management Committees (BMCs) at local body level.

The Convention on Biological Diversity was inspired by the world community's growing commitment to sustainable development. It represents a dramatic step forward in the conservation of biological diversity, the sustainable use of its components, and the fair and equitable sharing of benefits arising from the use of genetic resources. The Convention was opened for signature on 5 June 1992 at the United Nations Conference on Environment and Development (the Rio "Earth Summit"). It remained open for signature until 4 June 1993, by which time it had received 168 signatures. The Convention entered into force on 29 December 1993, which was 90 days after the 30th ratification. The first session of the Conference of the Parties was scheduled for 28 November – 9 December 1994 in the Bahamas. Biological Diversity Act of India3

Pursuant to the CBD, India enacted the Biological Diversity Act in 2002, and notified Biological Diversity Rules in 2004, to give effect to the provisions of this Convention. The Act is implemented through a three-tiered institutional structure at the national, state and local levels. The National Biodiversity Authority (NBA) has been set up in October, 2003 in Chennai.

The vision of NBA is the conservation and sustainable use of India’s rich biodiversity and associated knowledge with people’s participation, ensuring the process of benefit sharing for well-being of present and future generations. The mission of NBA is to ensure effective implementation of Biological Diversity Act, 2002 and the Biological Diversity Rules 2004 for conservation of biodiversity, sustainable use of its components and fair and equitable sharing of benefits arising out of utilization of genetic resources.

The NBA interalia deals with all matters relating to requests for access by foreign individuals, institutions or companies, and transfer of results of research to any foreigner. The State Biodiversity Boards (SBBs) constituted by the State Governments, deal with all matters relating to access by Indians for commercial purposes. The institutions of self-governments are required to set up Biodiversity Management Committees (BMCs) in their respective areas for conservation, sustainable use, documentation of biodiversity and chronicling of knowledge related to biodiversity.

2 https://www.cbd.int/ 3http://nbaindia.org/

6


Biodiversity and Sustainable Development

Sustainable development, according to the Brundtland Report of 19874, is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. The UN Rio+20 outcome document “The Future We Want”, highlights biodiversity as being critical in maintaining ecosystems that provide essential services, the very foundations for sustainable development and human well-being.

The Strategic Plan for Biodiversity2011-20205 views biodiversity as an opportunity for sustainable development. That is why the Plan’s20 Aichi Biodiversity Targets relate not only to conservation, but to addressing the underlying causes of biodiversity loss by mainstreaming biodiversity across all sectors of government and society. Overall, the Targets aim to bring about a considerable change to our lifestyles, and particularly to our development paradigm – over the next decade we must move towards sustainability and firmly away from inappropriate production and consumption.

The Sustainable Development Goals (SDGs), officially known as "Transforming our world: the 2030 Agenda for Sustainable Development", is a set of 17 "Global Goals" with 169 targets among them. The 2030 Agenda for Sustainable Development, agreed by the 193 States Members of the United Nations, sets out an ambitious framework of universal and indivisible goals and targets to address a range of global societal challenges. Biodiversity and ecosystems feature prominently across many of the Sustainable Development Goals (SDGs) and associated targets. They contribute directly to human well-being and development priorities. Biodiversity is at the Centre of many economic activities, particularly those related to crop and livestock, agriculture, forestry, and fisheries. Globally, nearly half of the human population is directly dependent on natural resources for its livelihood, and many of the most vulnerable people depend directly on biodiversity to fulfil their daily subsistence needs. SDG 146 and SDG 157 directly address the issues of conservation as follows;

Goal 14. Conserve and sustainably use the oceans, seas and marine resources for sustainable development.

A clear agenda has been formulated for promoting the ‘Blue Revolution’. For tracking the levels of marine pollution along the coastline, the country has developed the Coastal Ocean Monitoring and Prediction System. Additionally, an oil spill management system has been put in place for responding to emergencies arising out of oil spills. Further, the Integrated National Fisheries Action Plan, 2016 is being implemented to promote the livelihoods of fishing communities as well as the ecological integrity of the marine environment. Giving new impetus to port-led development, the Sagarmala programme is improving port connectivity, port-linked industrialization and coastal community development.

4 http://www.un-documents.net/our-common-future.pdf 5https://www.cbd.int/sp/ 6 https://sustainabledevelopment.un.org/content/documents/15836 India.pdf 7 http://ris.org.in/pdf/SDGs_Report_Chapter_15.pdf

https://sustainabledevelopment.un.org/content/documents/15836

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Goal 15. Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss.

The Strategic Plan for Biodiversity 2011-2020 and its 20 Aichi Targets provide an agreed overarching framework for action on biodiversity and a foundation for sustainable development. Among the Aichi Biodiversity Targets, the following measurable targets are particularly pertinent for SDG 15: Target 5: By 2020, at least halving deforestation and the loss of other natural habitats. Target 7: Sustainably managed areas under agriculture, aquaculture and forestry. Target 11: Protecting at least 17 per cent of land and 10 per cent of oceans through protected areas. Target 15: Restoring at least 15 per cent of degraded lands.

People are at the centre of sustainable development and ultimately the effectiveness of implementing SDGs depends on how well they are integrated into a decentralized governance framework. Despite putting in place Laws and Policies, the biodiversity extinction crisis shows no sign of abating, with human activities driving species losses Stemming the loss of biodiversity will therefore depend on changing people's attitudes and behavior If, as recent studies suggest8, human–biodiversity interaction outcomes are influenced by people’s perceptions of biodiversity rather than by objective measures, the role of ecological knowledge in influencing the relationship is a key dimension worthy of consideration. Conclusion

Over the next 15 years, the new sustainable development agenda aims at transforming

our world. The 17 Sustainable Development Goals (SGDs) make special emphasis on the dependence of economic, social and environmental dimension. Environmental dimension of SDGs is critical in achieving the 2030 Agenda and biodiversity conservation is central to this approach. The presentation would provide a comprehensive overview of status and trends of biological diversity in India as well as the associated science-policy regime.

8https://academic.oup.com/bioscience/article/66/7/576/2463167/Unpacking-the-People-Biodiversity-Paradox-A

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9


Recent advancement in fish harvest sector by ICAR-CIFT Dr. C.N. Ravishankar

Director, ICAR-Central Institute of Fisheries Technology, Kochi

E-mail:[email protected]

Introduction

With about 171 million tonnes of fish production which peaked at in 2016 globally, aquaculture contributed around 80.3 million tonnes and 90.9 million tonnes through the total capture production (FAO, 2018). Worldwide 59.6 million people engaged fisheries and aquaculture in 2006, out of that 19.3 million people engaged in aquaculture and 40.3 million people engaged in fisheries. In India fisheries sector is promises 14 million employment and income generation. Fishing has been an ancient occupation. It directly contributes approximately 10% of the total animal protein intake by humans. As far as per capita consumption is concerned, global fish consumption is growing at an average rate of about 1.5 percent per year. It was 9.0 kg in 1961 which touched 20.2 kg in 2015. Preliminary estimates for 2016 and 2017 pointed to further growth to about 20.3 and 20.5 kg, respectively (FAO, 2018). India is one of major fish producing countries in the world. It has an Exclusive Economic Zone (EEZ) of 2.02 million sq.km, a long coastline of 8,118 km and two major groups of Islands with rich and diverse marine living resources. The marine fisheries wealth is estimated to have the annual harvestable potential of 4.412 million metric tonnes. In the year 2017-18 the marine fish landings of India was 3.83 million tonnes which is 5.6% more than the preceding year (CMFRI, 2018). There were 1,99,141 fishing vessels operates in marine fisheries sector of India out of which mechanised, motorised and traditional artisanal vessels contributes about 36.5%, 36.9% and 26.6% respectively. Among the mechanized crafts fully owned by fishermen, 29% were trawlers, 43% were gillneters and 19% were dolnetters (CMFRI, 2012b). Where as in terms of total catch landed during year 2017-18, mechanized, motorized and artisanal contributed around 75%, 23% and 2% respectively (CMFRI, 2012b, 2015, 2018). Indian marine fisheries resource supports the livelihood of about 4 million people. The increased demand for fish has prompted the development of new harvesting techniques mainly fuel-efficient and resources specific craft and gear and responsible fishing techniques. The recent developments in fish harvesting techniques are briefly reviewed in this chapter. The ICAR-Central Institute of Fisheries Technology (ICAR-CIFT) set up in 1957 is the national institute in the country where research related to fishing and fish processing is undertaken. The institute started functioning at Cochin in 1957. As a contribution to the nation’s fishing sector, ICAR-CIFT focuses on basic, strategic and applied research in developing fuel efficient fishing vessels, responsible fishing gears, designing innovative implements & machinery for fishing, Eco-friendly technologies for responsible fishing and low-energy fishing technologies for the traditional sector. This institute has also been in the forefront of recommending standards for netting, netting yarn and netting twine used for fishing net and standardization of fishing gear accessories.

10


Fish harvest technology and responsible fishing

Fishing and related activities provide employment and economic benefits to large sections of the society. Fishing encompasses various processes of catching aquatic organisms. Use of fishing methods varies, depending on the types of fisheries, and can range from as simple process as gathering of aquatic organisms by hand picking to highly sophisticated fish harvesting systems, viz. aimed mid-water trawling or purse seining conducted from large fishing vessels. The targets of capture fisheries can range from small invertebrates to large fishes. The large diversity of targets in capture fisheries and their wide distribution requires a variety of fishing gears and methods for efficient harvesting. These technologies have been developed around the world according to local traditions and technological advances in various disciplines like hydrodynamics, acoustics and electronics. Filtering the water, luring and hunting, are the basis for most of the fishing gears and methods used even today.

Development of fishing crafts in India

Mechanisation of fishing crafts in India evolved through four stages, beginning with motorisation of some of the existing designs of traditional crafts, followed by introduction of mechanised craft (Gurtner, 1960). The traditional fishing activities has transformed by introduction of outboard motors in the existing crafts and gears operated in this sector. During the eighties, the Bay of Bengal Programme of FAO has developed beach landing crafts for Tamil Nadu and Andhra Pradesh, which was made of fiberglass for operating surf-beaten coasts. Concurrently, with the evolution of beach landing craft, introduction of small mechanised crafts which operated from harbours and sheltered bays received attention. Several standard designs of fishing crafts for different types of fishing operations has been developed by FAO and ICAR-ICAR-CIFT. One of the outcome of this mechanisation programme was the design popularly known as Pablo. Twelve standard designs of wooden fishing boats in the size range of 7.67 to 15.24 m were developed and introduced by ICAR-ICAR-CIFT, Cochin which gave a major boost to the mechanization programme of Indian fisheries. Designs for boats for fishing in rivers and reservoirs, pole and line fishing vessel, trawler-cum-carrier vessel, steel trawler-cum purse seiner, gillnetter were also developed by ICAR-ICAR-CIFT. FRP boats made up of a composite material of fibreglass and a polyester resin has gained wide acceptability as they are of light weight and having longevity and strength. The light, powerful diesel engine and hydraulic winch allow the use of reasonably large trawl nets on a vessel that is relatively small and inexpensive to run. During last five decades, remarkable changes have been made in new vessel design and construction and operations of modern fishing vessels (Gopal and Edwin, 2013).

Contributions of ICAR-CIFT in Fish Harvest Sector

ICAR-ICAR-CIFT has developed and disseminated standard designs of fishing vessels in the size range 7.67-15.24 m, suitable for various types of fishing under the Indian conditions and appropriate gear systems for trawling, seining, gillnetting, lining and trapping. Modernisation of fishing vessels and development of fuel efficient designs have been undertaken and newer craft materials have been introduced to reduce the cost of operation and increase the income of fishermen. Significant contributions of the Institute in recent years in harvest sector include the following:

11


Fuel efficient fishing vessels

19.75 m fuel efficient multipurpose fishing vessel; Sagar Harita

The fishing vessel, Sagar Harita, a 19.75 m long fuel efficient multipurpose fishing vessel designed by Fishing Technology Division of ICAR-CIFT and built by Goa Shipyard Limited (GSL). The vessel has met all the requirements of the Indian register of shipping (IRS) and ICAR-CIFT. This new generation energy efficient green fishing vessel is equipped with the latest technology solar panels, aiming to promote green energy and reduce the carbon foot prints. The solar panels fitted on the vessel cater the energy requirement for navigational lights, cabin lights etc. The vessel also incorporates an optimized hull design with a bulbous bow, fuel efficient propeller design and improved sea keeping characteristics. Modern tools and techniques including software simulation and model testing have been used for the refinement of the design. The ship's super structure above deck level has been made from FRP using the latest 'resin infusion technology' thereby significantly enhancing the sea keeping performance.

15.5 m deep sea fishing vessel; Sagar Kripa:

ICAR-CIFT has taken initiative to develop fuel efficient fishing vessels in view of high

expenditure incurred in mechanised fishing operations. A 15.5 m multi-purpose deep sea fishing vessel Sagar Kripa with steel hull was designed and developed with energy saving features. These include optimized hull design, optimized installed engine power, fuel efficient propeller and propeller nozzle. The commercial trials by the fishing boat operators have saved about 17% of the fuel cost.

Energy saving trawling technologies

Trawling is an active fishing method in which a bag shaped fishing gear is towed from mechanized fishing vessel. It is known to be one of the most energy intensive fishing methods.

Low drag trawls:

In excess of 60% of the total resistance in the trawl system is known to be contributed by

netting alone. Fuel consumption during trawling is directly related to the drag of the gear system. Substitution of large meshes in the front trawl sections has been reported to reduce the drag of the trawl system by about 7% and hence reduces fuel consumption in trawling. The reduced drag permits greater trawling speed and/or operation of larger trawl with the available installed engine power. Large mesh demersal trawls, have been extensively adopted by mechanized fishermen of north-west coast, Mangalore and Kerala, for resources like Ribbonfish, Squid, Horse Mackerel, Mackerel and Pomfrets, due to its low drag and fuel efficiency. Fuel cost alone constitute up to 75% of operational expenditure. Drag offered by trawl depends on factors like design and rigging of the net alone contributed 58% of the total drag offered by a trawl. Estimation of drag of commercial trawls in Kerala reveal that it ranges from 1.5 to 49.0 kN according to the design used. Adoption of optimised towing speed, thinner twines and large mesh to reduce twine surface area are found to bring down the drag and

12


hence the fuel consumption. Conventional trawls made of HDPE are with more drag due more twine surface area and weight of webbing. Ultra High Molecular Weight Polyethylene is

a stronger material compared to HDPE, which permit to use thinner twine for trawl fabrication. Trials of 24 m UHMWPE low drag trawl developed by ICAR-ICAR-CIFT revealed that average reduction of drag was 15% with 13% average reduction in fuel consumption and average 7.5% reduction in operational expenditure compared to HDPE trawls.

Cambered otter boards:

Otter boards are known to contribute 20-25 % of the total drag of the trawl system.

Introducing camber in otter board design is known to reduce resistance of the boards considerably, by increasing the hydrodynamic efficiency of the boards. ICAR-CIFT has introduced high aspect ratio, cambered otter boards for semi-pelagic trawling. Introduction of camber in otter boards reduces the drag of the trawl system by 4% with accompanying savings in fuel.

V-form otter boards:

The V-form otter boards are hydrodynamically efficient and have very inherent stability.

It is made of steel and do not utilize wood in their constructions. These boards do not plough or dig into the bottom and will tide over smaller bottom obstacles, thus becoming suitable for trawling in uneven and rocky grounds. V-form boards are cheaper and safe in shooting and hauling if properly rigged with a longer service life of 5-6 years. V-form type otter boards have become popular among trawler fishermen of southern India and Gujarat, since its introduction.

Eco friendly trawls for off bottom resources:

Demersal trawls are generally non-selective and a large number of non-target species and

juveniles are landed during trawling, in addition to its impact on benthic communities. Resource specific trawls for semi-pelagic resources have comparatively low impact on the benthic biota. ICAR-CIFT off bottom Trawl System (ICAR-CIFT OBTS) has been developed as an alternative to shrimp trawling in the small-scale mechanized trawler sector, after extensive field-testing. The system consists of an 18 m four panel semi-pelagic trawl with double bridles, front weights and vertically cambered high aspect ratio otter boards of 85 kg each. It facilitates harvesting of fast swimming demersal and semi-pelagic finfishes and cephalopods, which are mostly beyond the reach of conventional bottom trawls, currently used in commercial trawl fisheries in India.

Low energy and eco-friendly harvest technologies for the inland fisheries and traditional marine sector

Appropriate craft designs and improved gear designs such as optimised gill nets, lines and

traps have been developed and introduced for the inland fisheries. Improved and durable lobster traps with escape window for juveniles have been developed as substitute for traditional traps of short life span and low efficiency, for harvesting of spiny lobster. The rich tuna resources of the Lakshadweep waters are under-exploited as the fishing operations are still limited to traditional pole and line method. ICAR-CIFT has introduced large mesh gill

13


nets and monolines (monofilament long lines) in Lakshadweep waters, for targeted fishing of Tunas, Billfishes, Seerfishes, Carangids and Perches, in an effort to diversify fishing methods and improve catching efficiency.

Large mesh purse seine and power block for purse seine operations

Purse seining is one of the most efficient and advanced commercial fishing methods. It is aimed mainly at catching dense, mobile school of pelagic fish and includes all elements of searching, hunting and capture. Introduction of large mesh purse seines facilitated by ICAR-CIFT has led to the revival of small mechanized purse seine fishery in Kerala. The changeover of mesh size in the purse seine from the conventional 20 mm to 45 mm has shown good results and the purse seiners has been able to land larger size classes of high value species. The traditional fishermen and the purse seiners were targeting small pelagic like anchovies, sardines and small mackerels in the coastal waters. The purse seiners were also targeting the same resource in the coastal waters. There was severe competition and rifts between the tradition and mechanized purse seiners. With the introduction of large mesh purse seine, the fishermen could go to deeper and farther waters targeting large pelagic like tunas, seer fish, pomfrets and large mackerels thus reducing the competition and fishing pressure in the coastal watersExperimental fishing operations carried out from the purse seiner Bharat Darshan during the period 2007-10 in the depth range of 50 to 220 m revealed that the catch mainly comprised of large sized mackerels (62%), followed by tunas (16%), carangids (14%), miscellaneous fishes (6%) and pomfrets (2%). All the mechanised purse seiners based at the Cochin Fisheries harbour, Kerala have changed over to 45 mm mesh size purse seines and started operations in the deeper waters targeting skipjack tuna, little tunnies, carangids, black pomfrets, horse mackerels, barracudas, seerfish and mackerel.

Bycatch Reduction Devices (BRDs) for responsible fishing and sustainable resources

BRDs for trawls

Among the different types of fishing, trawling accounts for the highest rate of bycatch along with the target species. Almost 70-90% of the trawl catch is bycatch, among which, about 40% is constituted by juveniles that are invariably discarded resulting in two serious consequences- depletion of the resources and pollution of the marine water and the consequential threat to the ecosystem. Further, higher the quantum of bycatch the less will be the economic benefit accruing from the fishing operation. Bycatch is unavoidable in any fishing operation; only its quantities vary according to the type of the gear and its operation. Therefore, one of the important research focuses of the Fishing Technology Division was development of bycatch reduction devices. Bycatch reduction device (BRD) is a device aimed at reducing the catch of non-targeted and unwanted species of fish in shrimp trawling. While BRD is a broad term used to describe any device that can be employed to eliminate or reduce the bycatch, turtle excluder device (TED), though in principle a BRD, is a specialized form of BRD designed to eliminate turtles, sharks and rays also from the trawl. These devices have been designed and developed taking into consideration the differential size and behaviour pattern of shrimp and fish inside the net. BRDs include Fisheye which is stainless steel escape chute attached in the codend for the escape of actively swimming finfishes and rigid grid devices; and soft BRDs such as square mesh windows, Bigeye, Sieve net and International Award winning design Juvenile Excluder cum Shrimp Sorting Device (JFE-SSD) which have

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been evaluated and recommended for use in Indian waters. Sea turtles are endangered species. Various protection measures have been adopted the world over, including India, for its protection. ICAR-CIFT has developed an indigenous design of the turtle excluder device which is appropriate for the Indian conditions. ICAR-CIFT-TED is a single grid hard TED with top opening of 1000x800 mm grid size for use by small and medium mechanized trawlers operating in Indian waters. In the TED developed by ICAR-CIFT, great care has been taken to ensure 100% escapement of the turtles while escapement of fish and shrimp at the minimum possible level.

Square mesh codend

Trawling generates the largest quantity of bycatch among the different fishing methods.

The total bycatch is reported to be about 2% of the total landings of India and about 56% of the catch in trawlers was classified as bycatch. Use of small mesh codends is one of the reasons for high bycatch incidence in trawls. Selectivity estimates of trawl resources and estimation of the most optimum mesh size and shape for square mesh codend were derived using long-term experiments onboard Dept. Fishing Vessels of the Institute. The sizes of the codends were optimized based on these experiments and an improvement in the selection length by 10-20% for commercially important fishes was achieved by using square mesh codends. Based on the studies carried out by ICAR-CIFT, Gujarat had adopted square mesh codends in trawlnets operated along its coast in the year 2003. Similarly, based on the studies conducted by ICAR-CIFT along Sindhudurg coast, Maharashtra state has implemented the mandatory use of square mesh codends in trawls since 2018. The recommendations of ICAR-CIFT have been incorporated in the amendment of the Marine Fisheries Regulation Act (MFRA) of the Kerala state and use of 35 mm square mesh codend (for fish trawl) or 25 mm square mesh codend (for shrimp) is made mandatory.

Low-cost substitutes for conventional craft materials

Traditionally, wood is used for construction of fishing vessels in India which has become

scarce and costlier. Focused attention has been given in identifying alternate materials for fishing vessel construction, in order to reduce the dependence on traditional scarce wood species. Cheaper and readily available cultivated wood species with short life cycle such as rubber wood, fortified with dual preservative treatment using 7.5% ASCU and creosote, has been identified for construction of canoes operated in backwater and coastal fisheries. A number of preservative treated rubber wood canoes have been distributed for field operations by fishermen groups and cooperatives. The cost of the canoe is 35 – 40% less than a canoe of same size built of ‘Anjili’, the usually used wood. This saves the depleting forest wealth, helps the rubber farmer to get a better price for his underutilized wood and gives a durable, maintenance free boat at affordable cost to the poor fisherman especially of the South West and North East where rubber trees are grown. Designs of fiberglass crafts have been developed for operation in inland waters. Fibreglass sheathing as protection against borer attack and biodeterioaration and as preventive against environmental pollution while using preservative treated wood in boat construction has been popularized, in traditional sector. Use of Aluminium alloy for construction of inland and coastal fishing craft has been demonstrated. Durability, light weight, corrosion resistance, toughness and resilience, low maintenance and high re-sale value make aluminum alloy a good material for construction of fishing craft.

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Treated Rubber Wood Canoe

Central Institute of Fisheries Technology has evolved a simple technology for

development of traditional fishing canoe from the rubber wood, which comes as a waste from rubber plantations. Though rubber wood is comparable to many structural timbers in terms of mechanical properties and working qualities, it is highly perishable under marine conditions. The study proved rubber wood as suitable for construction of canoe after upgrading by chemical preservative treatment. The conventional prime quality boat building timbers are very scarce and have become very costly. Traditional fishermen using wooden canoe find it extremely difficult to afford the cost. The new technology can reduce construction cost of small canoes by 35-40%.

FRP-Sheathed Rubber Wood Canoe

ICAR-Central Institute of Fisheries Technology has developed a fibre glass reinforced

plastic (FRP) sheathed rubber wood canoe for operation in marine and inland waters. The rubber wood, which comes as a waste from rubber plantations is upgraded through chemical preservative treatment and the canoe made using the treated wood is further given a sheathing of FRP. The technology has made possible the utilization of rubber wood and also provided additional dimensional stability through sheathing. The FRP sheathing provides water proofing, reduces maintenance, resistance to impact and abrasion and prevents attack of marine borers and other decay causing organisms besides giving an extended service life and better appearance for the wooden canoe. Canoe made of treated rubber wood and sheathed with FRP will give a maintenance free service life of 15-20 years.

ICAR-CIFT Collapsible Fish Trap

ICAR-CIFT improved the design of traditional trap as collapsible fish trap (1 m×0.6 m×0.6m) with two rectangular and square frames with stainless steel. HDPE webbing of 80 mm mesh size is used as cover of the trap to allow fish to enter. Two entrance funnels made of plastic mesh are fixed on both sides. These traps were supplied to local fishermen and experimental trials were conducted along backwaters of Vypeen Island, Kumbalangi, Cheranellor and Varapuzha. Etroplus suratensis, Lutjanus argentimaculatus, Lates calcarifer, Epinephelus sp, Scylla serrata are the common target species and the trap can be set and hauled after 2-3 days of soaking. Average catch/haul is 1.5 kg. Design of the trap is simple and any fishermen can adopt the technology and is 40% lighter in weight and durability is 3- 4 times more than the conventional traps. Cost of ICAR-CIFT collapsible fish trap is only 50% of the conventional bamboo traps with same dimension. ICAR-CIFT collapsible fish trap will be a better option for the traditional fishermen to improve the livelihood.

Myctophid trawl (28.4 m & 45 m)

Myctophids are the most abundant group of mesopelagic fishes in the Indian Ocean. About

137 species of myctophids are reported in the Indian Ocean. About 75% of total global catch of mesopelagic fishes is accounted by myctophids. Two mesopelagic trawls (28.4 m and 45 m) with four equal panels were designed and operated from FORV Sagar Sampada and ICAR-CIFT

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research vessel R.V. Matsyakumari-II. Estimated trawl drag for 45 m trawl in terms of towing speeds of 2to 3kn range from 4.9 to 7.3 t. The new mid-water trawl system designed to attain largermouth area, smoothly tapering trawl body with small meshes in belly and codend, which can be towed at about 2.5 kn is adjudged to be appropriate, taking into consideration available information on biological characteristics and behavior of myctophids, fishing conditions and vessel characteristics.

ICAR-CIFT Off-bottom Trawl System (OBTS)

Trawler fishermen in India cannot depend on shrimp and associated species alone for

viable commercial operations any more, and there is need to adopt responsible alternate trawl systems for harvesting large demersal and semi-pelagic species. ICAR-CIFT developed as an alternative to shrimp trawling in the small-scale mechanized trawler sector, after extensive field-testing. It is capable of attaining catch rates beyond 200 kg h-1 in moderately productive grounds and selectively harvest fast swimming demersal and semi-pelagic finfishes and cephalopods, which are generally beyond the reach of conventional bottom trawls, currently used in commercial trawl fisheries in India. ICAR-CIFT OBTS has been developed and perfected after extensive field trials and observations, using acoustic gear monitoring instrumentation and inference from statistical evaluation of catch, over an extended period.

Nano Cerium oxide, Titanium oxide & Iron oxide coating for corrosion resistance in boat building steel.

BIS 2062 carbon steel is extensively used for fishing boat construction and is highly

susceptible for corrosion in the hull, welding joints and coating failures under marine environments. This technology demonstrates the application of novel multifunctional nano metal oxide mixtures comprised of iron, titanium and cerium as marine coating to prevent corrosion. The electrochemical performance of nano metal oxide mixture coatings, applied over boat building steel, was evaluated inNaCl medium. The thin film surface coatings showed an efficient corrosion resistance with increased polarization resistance and low corrosion current density. The electrochemical impedance spectral data exhibited the improvement in the polarization resistance of outermost surface and internal layers. The coating responded faster recovery to normal state when subjected to an induced stress over the coating. The nano material in the coating behaves as a semiconductor; this enhanced electronic activity over the surface of the steel. The photo oxidation behavior of Fe2O3 and TiO2, deter the microbial attack

Biofouling resistant polyethylene cage aquaculture nettings: A new approach using polyaniline and nano copper oxide

Biofouling in aquaculture cage nets causes occlusion of mesh openings, thereby increasing

weight and drag, deformation of cages due to the ensuing stress, reduction of volume, thereby decreased stocking density per area, anoxic condition due to disruption of dissolved oxygen flow, blocking of food waste diffusion, restriction of water exchange, increased hydrodynamic force, all of which adversely impacted fish health. It has been reported that removal of fouling from a cage net costs 25% of the total project budget. Cages are fabricated mainly with high density netting whose non polar nature makes incorporation of antifouling biocides difficult. The surface of polyethylene needs to be modified to develop

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strategies against fouling. The novel approach employed by ICAR-CIFT was to synthesise a coating of polar or conducting molecule over non-polar polyethylene to incorporate antifouling biocides thereby rendering protection to protect the polyethylene aquaculture cage nets from biofouling.

Use of advanced fish finding and navigation techniques

Recent advances in technology have provided fishermen with equipment to reach the potential fishing ground accurately (Global Positioning Systems), detect the presence of fish acoustically (echosounder and sonar), thus saving the search time and fishing time and hence saving energy. These advances in technology have been popularized among fishermen, in collaboration with agencies like MPEDA and Department of Fisheries, for bringing down fuel use and environmental impact through fuel use. This, coupled with affordability and subsidy support, has resulted in significant penetration of GPS and Echosounder among small mechanized commercial fishermen, all along the coast.

Fishing craft and gear materials

Various cost effective protective measures against bio deterioration of wooden fishing vessels have been developed and are in use. Use of low cost timber like rubber and coconut have also been experimented successfully for small canoes. In India, ICAR-CIFT which plays a major role in the development of harvest technologies has also developed aluminium alloy sheathing for wooden fishing vessels, cathodic protection against marine corrosion in fishing boats, new substitutes for propeller material for cost savings, marine anti-corrosive paints, marine antifouling paints, chemical wood preservatives, indigenous resin based protective coatings for wooden crafts, ferrocement for boat building, rubber wood canoes, fibreglass reinforced plastic coated fishing canoes. Primarily, mechanized boats were using local gear. Major advances in fibre technology, along with the introduction of modern gear materials, have directly influenced and brought about important changes in the design, dimensions and method of handling fishing gears. Extensive use of synthetic materials like PA, PE and PP have perceived in 1960s which created a revolution in fabrication of fishing gears. Today, the entire fisheries sector uses only synthetic fibers for gears. Twisted netting yarns and braided netting yarns of different sizes are available in the country. Combination rope of Polyethylene and Polypropylene (Danline) and Polyamide monofilament is being extensively used as an import substitute for tuna and shark longlines. The development of combination wire rope as an import substitute for deep-sea fishing is a recent innovation which has now been commercialised. ICAR-CIFT has standardised specifications for the use of polypropylene multifilament netting yarn with lower specific gravity and better tenacity than nylon (Silas, 2003; Meenakumari, 2011).

Conclusion

In recent years, the developments in harvest technologies in fisheries sector have taken place rapidly. ICAR-Central Institute of Fisheries Technology has contributed greatly to the revolution of fishing industry as well as technology diffusion programmes in a very significant way in the fisheries sector across India. While the fisheries sector is facing challenges in terms of excess capacity of fleet, diminution of fish resources and degradation of the fisheries environment in the coastal waters. The under-utilised and resources in the deeper waters hold

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potential along with rapid expansion envisaged. It’s very imperative to have appropriate technology for application of resource conservation in the shelf waters under an appropriate management plan and diversification of fishing to unconventional resources such as mesopelagics, oceanic cephalopods and large pelagics in the deeper waters. Minimisation of harvest and post-harvest losses, development of technologies for reducing carbon and ecological footprints in the harvest sectors are areas which need focussed attention. Today fisheries sector is watched by many as a sunrise sector as it helps in alleviating food security as well as supports many auxiliary sectors. ICAR-CIFT has major contributions for this transformation. Over the years institute has carried out research on harvest and post-harvest aspects of fish extensively based on the sectors need and developed many ready to transfer technologies. Notable ones in harvest sector include design and construction of fishing vessels, ecofriendly fishing gears, satellite based imaging system to locate fishing ground, automated fish hauling systems. The research information generated is transferred to the end users by adopting suitable extension methodologies.

References CMFRI (2012b) Marine fisheries census 2010 Part-I India, Department of Animal Husbandry,

Dairying & Fisheries and Central Marine Fisheries Research Institute, Cochin: 98 p

CMFRI (2015) Annual Report 2014-15. 353 p, Central Marine Fisheries Research Institute, Cochin


FAO (2018) The State of World Fisheries and Aquaculture, Rome. 227 p

Gopal, N. and Leela Edwin, 2013, Technology Evaluation Model for Rural Innovations – Case Study of Rubberwood Fishing Craft for the Small-scale Fisheries Sector Fishery Technology. 50(4): 331p

Gurtner, P. (1960) Development of a boat for India’s surf coast, In: Traung, J.O. (ed.), Fishing Boats of the World 2, Fishing News (Books) Ltd., London. pp585- 596

Meenakumari, B. (2011) Fish Harvest Technology. In: Handbook of Fisheries and Aquaculture (Ayyappan, S. Ed.), Indian Council of Agricultural Research, 1116 p

Silas, E. G. (2003) History and development of fisheries research in India. J. Bombay Nat. Hist. Soc., 100 (2 & 3): 502-520

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Marine fisheries in India Dr. T. V. Sathianandan

Principal Scientist & Head, FRAD, Central Marine Fisheries Research Institute, Kochi


As per the FAO 2018 report, India stands at sixth position in marine fish production after

China, Indonesia, USA, Russia and Peru. The contribution towards world marine fish production by India is 4.5%. In India, the marine fisheries sector provide livelihood support to about 3.79 million fisher population and employment to nearly two million fishermen. The country earns more than ₹ 45,000 crore by export of marine products to more than 100 countries, mainly to USA, South East Asia and European Union.

The mainland of India is composed of nine maritime states namely West Bengal, Odisha,

Andhra Pradesh and Tamil Nadu along the east coast; Kerala, Karnataka, Goa, Maharashtra and Gujarat along the west coast; and two union territories Puducherry and Damen & Diu. The length of the coast line (including island territories) is 8129 km, Exclusive Economic Zone (EEZ) is 2.02 million square kilometre, continental shelf area is 0.50 million square kilometre and Inshore area below 50 meter depth is 0.18 million square kilometre. As per the information generated under the Marine Fisheries Census 2016, in India there are 0.89 million fishermen families living in 3477 marine fishing villages. The total fishermen population is 3.77 million out of which 0.93 million are active fishermen. Fishing in Indian waters is carried out by mechanized, motorized and non-motorized sectors with 42,656 mechanised vessels, 95,957 motorised vessels and 25,689 non-motorised vessels. The marine fisheries resources harvested by these vessels are landed in 1265 landing centers which include major and minor fishing harbours.

Estimation of the quantity of different species of marine fish and shell fish resources

commercially harvested annually from the Indian EEZ is a part of the scientific data collected by the ICAR - Central Marine Fisheries Research Institute (CMFRI) for monitoring the marine fishery resources as one of its major mandate. Presently this information is collected online from landings centres and fisheries harbours by following a statistically sound scientific data collection system developed by CMFRI and centrally processed at its headquarters to arrive at resources wise landings estimates every year. The data generated is stored in National Marine Fisheries Data Centre (NMFDC) of CMFRI. Every year about 700 to 800 species are recorded in the landings by more than 25 types of gear craft combinations. When a longer period data is examined there are more than 1200 species found in the landings along the Indian coast. In addition to landings information on fishing effort is also collected both in terms of fishing units as well as fishing hours. The following figure shows the growth in marine fish harvest in India over years.

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India’s marine fish production estimated for 2018 is 3.49 million metric tonnes. Among

the nine maritime states, Gujarat is in the first position with 7.80 lakh tonnes landings (22.4% of total) followed by Tamil Nadu with 7.0 lakh tonnes (20.1%) and Kerala 6.43 lakh tonnes (18.4%). Karnataka was in the fourth position with 4.52 lakh tonnes (13.0%) followed by Maharashtra 2.95 lakh tonnes (8.5%), Andhra Pradesh 1.94 lakh tonnes (5.5%), West Bengal 1.60 lakh tonnes (4.6%), Odisha 0.89 lakh tonnes (2.6%), Daman & Diu 0.68 lakh tonnes (2.0%), Goa 0.59 lakh tonnes (1.7%) and Puducherry 0.45 lakh tonnes (1.3%).

Indian mackerel is the major resource with a contribution of 2.84 lakh tonnes (8.1%)

towards the total landings, Oil sardine used to be the major resource but in 2018 its position dropped down to 9th with 1.55 lakh tonnes landings. Other major contributing resources were cephalopods 2.21 lakh tonnes (6.3%), non-penaeid prawns 1.94 lakh tonnes (5.6%), ribbon fish 1.94 lakh tonnes (5.6%), penaeid prawns 1.92 lakh tonnes (5.5%) and threadfin breams 1.84 lakh tonnes (5.3%). Region wise contribution towards total landings in 2018 was north-east 0.25 million tonnes (7.1%), south-east 0.94 million tonnes (27.0%), south-west 1.15 million tonnes (33.1%) and north-west 1.14 million tonnes (32.8%).

Maximum landings took place during October - December period with 1.13 million tonnes (32.3%), followed by 1.00 million tonnes (28.7%) during January - March, 0.81 million tonnes during July - September (23.3%) and 0.54 million tonnes during April - Jun. In the three sectors, the major portion of the harvest was by the mechanized vessels contributing 2.84 million tonnes (81.3%) of the total landings in 2018. The contribution by motorized vessels was 0.61 million tonnes (17.4%) and the harvest by non-motorized country crafts was only 0.04 million tonnes (1.3%). Pelagic resources dominated in the landings with 1.86 million tonnes (53.4%) followed by Demersal resources with 0.94 million tonnes (27.1%), Crustaceans with 0.46 million tonnes (13.1%) and Molluscs with 0.23 million tonnes (6.5%). The following figure shows the number of species landed in different maritime states in 2007 and 2008.

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1950 1960 1970 1980 1990 2000 2010

Land

ings

( m

illio

n to

nnes

)

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Status of Inland Fishery Resources of India V. V. Sugunan

Assistant Director General (Rtd.), Indian Council of Agricultural Research, New Delhi


Introduction

Fish production in India is on a high growth trajectory thanks to the Government of India’s recognition of fisheries and aquaculture as a major driver for food-, nutritional- and livelihood security of people. Fish is the cheapest animal food that is accessible to the poor at affordable prices. This role of fish in the nutritional security of Indian masses is apparent from the fact that poultry meat (the other animal food and the most popular meat in the country) is available at the rate of 1 kg broiler meat /caput/annum while fish is available at the rate of 9.8 kg/caput (CSO-MFS, 2011: Ayyappan and Sugunan, 2009). While more than 14 million fishers and fish farmers depend on fishing and fish farming for their livelihoods, many times more that number eke out their living through support and ancillary activities such as fish processing, trade and making of fishing crafts and gear. Recently, a dedicated Department for Fisheries has been created in India under the newly formed Ministry of Fisheries, Animal Husbandry and Dairying, which has been entrusted with a task of doubling farmers’ income and achieving a target fish production of 15.0 million t by 2022 under the Blue Revolution Scheme.

Fish production in India has achieved a remarkable 16-fold increase during the last six decades to reach 12.59 million t in 2017-18, propelling the country to the position of second largest fish producing nations in the world. During this period, the share of inland fish production has increased from 29% to 68% and the present inland fish production has reached 8.9 million t (Fig 1), 80% of which is accountable to freshwater aquaculture. Several factors contributed to this commendable success story. While mechanization of fishing boats, improved designs of craft and gear and increase in fishing effort have led to the increase of marine capture fisheries from 0.53 million t to 3.69 million t, it was the emergence of aquaculture as viable vocation and industry that resulted in increasing inland fish production from 0. 2 to 8.9 million t during the last six decades. Gross Value Added (GVA) from fisheries is estimated at Rs 1,33,492 crore, which contributed to nearly 1% of the national GVA, at current prices in 2016-17 and about 5.37% of agriculture GVA (DoF, 2019).

Development of innovative technologies and their field trials by the research institutes, coupled with massive adoption and up-scaling by the state extension machineries have played a major role in the fisheries development in the country. Technological developments such as induced breeding of Indian major carps; composite fish culture; technologies for hatcheries and seed production and culture of catfishes, prawns & shrimps; genetic improvement of rohu; technologies for fish health protection; and feed formulations have been the highlights of this development.

Large-scale expansion of fish and shrimp culture activities in the country is equally attributable to the never ending enterprising spirit of our fishers and fish farmers and their willingness and quintessence to seek and imbibe modern technologies and techniques from all over the world.

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More and more progressive farmers and companies are now coming forward to import technologies in fish/shrimp seed production, and culture and post-harvest processing from different parts of the world. The annual earnings from export of 1.4 million t of fish and shellfish are about Rs 45,107 crore, accounting for 18% of the country’s total agriculture export.

Inland fisheries resources and their management

Inland fisheries resources of are rich and diverse, comprising rivers, canals, ponds, lakes, reservoirs and floodplain wetlands. Inland fish production systems in the country fall under the capture fisheries of the rivers, estuaries, lagoons and lakes; aquaculture in ponds; and various forms of enhancements (mainly culture-based fisheries and stock enhancement), being practiced in reservoirs, lakes and floodplain wetlands (Table 1). Catch from the rivers and estuaries is falling drastically due to negative impact of human activities on the aquatic environment. In a typical capture fishery, the wild untended stocks of organisms are harvested with little human intervention on habitat variables or the biotic communities, while in a culture fishery (aquaculture), the production process is based on captive stocks with a high degree of effective human control over the water quality and other habitat variables. Fish production systems that are intermediate to capture and culture are collectively called 'enhancement'. The marine fishery is the example of capture fisheries and the intensive aquaculture of fish and prawn in small ponds is the typical example of culture fishery (Fig 2).

Table 1. Inland fisheries resources of India and their modes of management

Resources Resource size Mode of management

Inland

Rivers (km) 29,000 Capture fisheries

Mangroves (ha) 356,000 Subsistence

Estuaries (ha) 300,000 Capture fisheries

Freshwater ponds (ha) 2,430,000 Aquaculture

Brackishwater ponds (ha) 1,140,000 Aquaculture

Secondary Saline soil areas (ha) 9,000,000 Aquaculture (Potential)*

Estuarine Wetlands (ha) 40,000 Aquaculture

Lagoons (ha) 190,500 Capture fisheries

Large and Medium reservoirs (ha) 1,667,809 Enhanced capture fisheries

Small reservoirs (ha) 1,485,557 Culture-based fisheries

Floodplain Wetlands (ha) 202,213 Culture-based fisheries, Enhanced capture fisheries

Upland Lakes (ha) 720,000 Capture fisheries Source: Ayyappan and Sugunan, 2009 *ICAR,2006

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Aquaculture

Freshwater aquaculture

Annual freshwater aquaculture production is estimated at 7.0 million t. Considering that the current level of utilization of the potential water area of 2.4 million ha is only 40%, sufficient scope exists for both vertical and horizontal expansion of aquaculture. Two important technologies viz., induced fish breeding and composite carp culture have triggered the growth of carp culture in the 1970s. With the adoption of these technologies, the mean production level in FFDA (Fish Farmers’ Development Agency) ponds across the country has gone up to over 2.9 t/ha/year (DAHD&F, 2011), even while several farmers are able to achieve much higher production levels of 8-10 t/ha/year. In recent years, several new technologies have emerged and some species have been introduced which catalyzed the growth of Indian aquaculture. The new technologies are (1) development of improved rohu (Jayanti) with 70% higher growth, developed through a selection programme and (2) multiple breeding and off-season breeding of carps that enabled seed availability at different times of the year. The two introduced species viz., pangas (Pangasianodon hypophthalmus), and GIFT tilapia. are becoming increasingly popular among fish farmers across the country. Currently, pangas is cultured in 3,863 ha and GIFT tilapia in 4,787 ha with production of 26,293 t and 7,249 t respectively (DoF, 2019). More and more farmers are adopting the culture of these two species, after the introduction of Recirculatory Aquaculture Systems (RAS) and cage culture in reservoirs. In the near future, their contribution to freshwater aquaculture is expected to increase substantially. Apart from culture of Indian major carps, there are opportunities for developing culture of high value species like catfishes, magur (Clarias batrachus) and butter fish Ompok spp.; and murrels (Channa striatus). Coldwater fisheries and aquaculture, with prized species like trout and mahseers in hill states like Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Sikkim and Arunachal Pradesh are given high priority in R&D efforts.

Seed and feed

Production of quality seed in adequate numbers and its distribution through a reliable value chain are the most critical input in aquaculture. The private enterprise in carp seed production in the country is fast growing with over 1000 hatcheries, producing over 52 billion fry annually (DoF, 2018). With an investment of about Rs 70,000, the newly devised portable carp hatchery can produce over 2 crore seed in 20 batches in a three months period (from July-September). Further, the net profit in raising carp fry in two crops of 15-20 days, is about Rs 90,000/ha. In spite of these strides, there is a nagging shortage of fish seed in the country.

Establishment of adequate number of hatcheries in different regions is required to obviate the need for long distance transportation. There is also a need to create sufficient rearing space to ensure uninterrupted supply of adequate number of fingerlings. There is an urgent need to create adequate facilities to produce the seed of newly introduced exotic fish, pangas. It is a matter of concern that most of the seed of this species is arriving in the country through unauthorized overseas trade channels. All-male seed need to be used for culturing GIFT tilapia. At present, production and distribution of its seed is regulated through the Marine Products Export Development Agency (MPEDA), which has limited capacity as a bulk supplier. Establishment of a supply chain with higher capacity is needed. Proper value chains for the production and supply of seed of different species is an essential prerequisite for healthy growth of the aquaculture sector. Considering the projected horizontal and vertical expansion of freshwater aquaculture, the feed

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requirement in 2020-21 is estimated at 10 million t, 30% of which would be commercial pelleted feed. Recent technological innovations, such as multiple carp breeding, design of portable hatcheries, development of improved rohu, and protocols of intensive carp culture have augured well for keeping the pace of development in freshwater aquaculture.

Species diversification

Lack of species diversification is a major gap in freshwater aquaculture. At least 15-20 species of finfish and shellfish including giant freshwater prawn, catfishes and ornamental fishes are lined up for commercial production to meet the demand from domestic and international markets. In order to facilitate species diversification in freshwater aquaculture, the research institutes in the country have launched major efforts on seed production of selected species at the national level, by setting up model production units. Other major issues are the need for appropriate leasing policies for public water bodies and effective post-harvest and marketing infrastructure including cold chains.

Major R&D efforts on the anvil are related to breed improvement, fish genomics, transgenics, bio-remediation and vaccines. In view of the shrinking freshwater availability and increased waste water generation, production technologies with minimum water requirement and waste water recycling are also getting research attention. Further, in view of the emerging market for organic farmed fish, the emphasis is being laid on wider adoption of organic farming practices and certification systems so that these contribute to at least 10% of the total aquaculture production for meeting the niche market.

Integrated fish farming systems

Integrated fish farming systems (IFF) entail synergizing different components of agriculture such as field crops, animals, poultry and fish to conserve resources and optimize resource use and outputs. Often, by-products and wastes from one segment act as inputs for another and thereby cutting down the production cost drastically. By recycling the organic wastes, integrated farming systems become an instrument to achieve sustainability and reduce risks of

environmental degradation. It includes, agri-aquaculture based systems, such as horticulture-fish, mushroom-fish, sericulture-fish, vermicompost-fish and aquatic weed-fish systems. Animal husbandry-based systems include cattle-fish, pig-fish, goat-fish, rabbit-fish, poultry-fish, and duck-fish systems (ICAR, 2011). Rice-fish farming is a traditionally followed IFF in many parts of India for centuries. Recent technological upgradations have made these systems more economic and attractive propositions. A sizeable portion of the 18 million ha of canal-irrigated, 6 million ha of low and rain-fed, 3 million ha of deep water and 1 million ha of coastal wetland rice culture systems are suitable for rice-fish cultivation, particularly in the eastern India, which accounts for more than 60% of such resources . Fish and shellfish species suitable for freshwater rice ecosystems are Indian major carps (catla, rohu, mrigal), catfishes (magur and singhi), medium carps (Labeo bata and calbasu), minor carps (Amblypharyngodon mola and barbs), snakeheads (murrels) and perches (koi and gourami). There is a need for adoption of technologies and adaptation of the existing traditional knowledge on rice-fish farming to all areas that are suitable for integrated farming practices.

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Fish culture is also an ideal way of recycling sewage as being practiced extensively in Kolkata for many decades. Properly treated city sewage is rich in nutrients and can be effectively utilized as an irrigation medium for rice-fish culture. Apart from cutting the cost on fertilizers, this is an efficient way of treating and recycling the city wastes. Sewage enriched systems have the productivity potential of 7.8 t of rice (in two crops) and 680 kg of fish and prawn/ha.

Coastal aquaculture

The vast coastal aquaculture resources in India are grossly underutilized. Of the 1.24 million ha of brackishwater resources available, only 152,595 ha (12%) is currently utilized, leaving ample scope for further horizontal growth (DoF, 2019). Shrimp culture in India is not only fast recovering from the collapse of tiger shrimp (Penaeus monodon) in the 1990s, due to environmental issues and disease problems, it is also growing at a very fast rate due to introduction of a new species viz., Mexican white shrimp, Litopenaeus vannamei. It now contributes 91% (622,327 t) to the total shrimp production of 680,000 t. Production of tiger shrimp and scampy (Macrobrachium rosenbergii) are very limited at production levels of 57,688 t and 9,983 t respectively (DoF, 2019). Vannamei is cultured by using SPF (Specific Pathogen Free) brood stocks procured from overseas suppliers and distributed to Indian hatcheries under the regulatory regime of the Coastal Aquaculture Authority (CAA). The present facilities for producing the seed is too inadequate to meet the mounting demand. There is a need to increase the network of hatcheries to produce and supply vannamei seed by following the regulations set by CAA. Scope exists for recovering the tiger shrimp and scampy farming through installation of hatcheries and encouraging farmers to culture them. The technologies available for culturing sea bass (Lates calcarifer) and Indian white shrimp (Fenneropenaeus indicus) remain yet to be commercialized. There is also an urgent need to develop seed production and culture systems for milk fish (Chanos chanos) and pearl spot (Etroplus suratensis).

Open water fisheries

The open water fisheries comprise the capture fisheries of rivers, upland lakes, estuaries

and lagoons and the enhancement regimes of reservoirs and floodplain wetlands. Rivers

Different river systems of the country, having a combined length of 29,000 km, provide

one of the richest fish genetic resources in the world. Their highly diverse natural fish fauna characterizes Indian rivers. The Gangetic system alone harbors not less than 265 species of fish. Similarly, 126 species belonging to 26 families have been recorded from Brahmaputra system (ICAR, 2011). The peninsular rivers have been reported to bear at least 76 fish species. The riverine scene is a complex mix of artisanal, subsistence and traditional fisheries with highly dispersed and unorganized marketing system, which frustrates all attempts to collect regular data on fish yield. A firm database on fish production trends of rivers is still elusive. Based on the information collected by CIFRI on selected stretches of the rivers Ganga, Brahmaputra, Narmada, Tapti, Godavari, and Krishna, fish yield from these rivers vary from 0.64 to 1.64 t per km, with an average of 1 t per km (Sugunan and Sinha, 2001). The catch statistics over the years indicate some disturbing trends in the riverine fisheries especially the Ganga. A sharp decline in fish production from five stretches of the Ganga viz., Kanpur, Allahabad, Buxar, Patna and Bhagalpur

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is testimony to the deleterious effects of environmental changes on fish output. Average fish production from Ganga at Allahabad used to be around 205 t during the period between 1958-59 and 1965-66, which has declined to 59 t during 1996-97. More marked is the fall in the production rate of prized Indian major carps, which declined from 91.35 t in the 1950s to an abysmal 4.9 t in 1996-97 (Table 2). Similar decline in catches are reported from Brahmaputra (Pathak, 2000; Table 3), Godavari and other rivers. Decline of fish populations in rivers is universal phenomenon due to a variety of factors including destruction of habitat, effluent discharge and cascading effect of dams and other obstructions. Indian rivers produce much less fish than their biogenic potential (Sugunan and Sinha, 2001).

Table 2. Qualitative and quantitative decline in fish catch (t) from Ganga Allahabad

1958-59 to 1965-66

(%) 1973-74 to 1985-86

(%) 1989-90 to 1994-95

(%) 1996-97 (%)

Major carps

91.35 44.5 40.44 28.7 11.04 11.5 4.94 8.3

Catfish 46.66 22.7 30.82 21.9 21.5 22.5 14.28 24.1

Hilsa 19.94 9.7 0.87 0.6 0.92 1 2.47 4.2

Misc. 47.48 23.1 68.79 48.8 62.1 65 37.61 63.4

Total 205.43 140.92 95.56 59.3

Patna

1986-89 1990-93 1996-97

Total 57.73 37.70 18.00

Bhagalpur

1958-59 to 1965-66

(%) 1973-74 to 1983-84

(%) 1996-97 (%)

Major carps

16.62 18.2 10.06 10.8 7.31 20.4

Catfish 19.43 21.4 25.21 27.1 14.91 41.7

Hilsa 4.08 4.5 0.87 0.9 0.38 1.1

Misc. 50.82 55.9 56.96 61.2 13.20 36.8

Total 90.95 93.10 35.80

Source: Sugunan and Sinha, 2001

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Table 3. Changes in fish yield and catch structure in Brahmaputra during the 1970s and 1990s

Groups 1973-79 1996-98 • Change

Average catch (kg day-1)

%

Average catch

(kg day-1)

%

Total 196.9 137.3 -30

Major carps 38.2 19.4 18.7 13.6 -30

Minor carps 27.8 14.1 9.6 7 -50

Catfishes 46.8 23.76 19.5 14.2 -40

Featherbacks 7.1 3.6 8.0 5.8 +61

Hilsa 22.1 11.2 2.9 2.1 -81

Prawn 9.8 5 2.9 2.1 -58

Misc. & Others 45.1 22.9 75.8 55.2 +141

Source: Sugunan and Sinha, 2001

Upland lakes

Information on the fisheries activities in the upland lakes is scanty. Natural lakes situated in the colder upland regions of India are estimated to cover an area of 720,000 ha (Jhingran, 1988). These lakes support a lucrative indigenous and exotic fish fauna comprising schizothoracids, mahseers, trout, tench, Crucian carps and the mirror carp. Annual fish yields in peninsular upland lakes range between 1.8 and 9.3 kg/ha in Kodaikanal, 16.7 and 49.5 kg/ha in Yercaud, and 33.0 and 111.0 kg/ha in Ooty (Vass, 1988). The yield rates from Himalayan lakes range from 8.0-22.5 kg/ha in Dal lake, 10.0-28.5 kg/ha in Anchar, 15-45.0 kg/ha in Wular, 2.0 to 6.0 kg/ha in Manasbal and 5.0 to 15.0 kg/ha in Sivalik lakes. The catches in most of these lakes are dominated by C. carpio with sizeable contribution to schizothoracids and mahseers in northern lakes and Oreochromis mossambicus in Deccan lakes.

Management norms for these upland lakes are virtually non-existent and limnological information is available only from a few of them. Some of these lakes in Kashmir Himalayas are experiencing a disturbing trend – the schizothoracids giving way to the common carp. The common carp introduced into the Kashmir valley now contributes 65-78% of the total fish landings of the region. The catch structure and composition have significantly altered in recent years. A similar situation has been observed in case mahseers in Kumaon and Sivalik lakes. In Bhimtal Lake, the common carp constitutes 21-67% of the catches leading to a decline by 27-45% of the golden mahseer (Tor putitora) population. Very little is known about the fishery potential

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of upland lakes. On account of their remoteness and the low temperature regime, drastic increase in yield and production are not expected from these water bodies. Estuarine fisheries

Various estuarine systems spreading over 300,000 ha form an important component of the fisheries resources of India (Table 4). The fisheries of estuaries are above subsistence level and contribute significantly to the production. The average yield is estimated to vary from 45 to 75 kg/ha (Jhingran, 1991). Though the fisheries of various estuarine systems have been studied during the last few decades, a continuous monitoring of the fisheries is being done only in the Hooghly-Matlah estuarine system, the largest estuarine complex in India. River course modifications have a negative impact on the estuarine fish populations. Mahanadi estuary is characterized by poor tidal oscillations and flood discharge due to sand bar formation in the sea mouth (Jhingran, 1988). This has already affected fish yield from the estuary. The fisheries of Godavari estuary too have been seriously affected by sand bar formation. Fisheries potential of Tapti estuary drastically declined after commissioning of the Ukai dam. Mushrooming industries on the bank of Mahi pose serious pollution problems in the estuary.

Table 4. Major estuaries and associated inland water bodies in India and their fish production levels (After Jhingran, 1988).

Estuary Area (ha) Annual fish Production (t)

Major fisheries

Hooghly-Matlah 234,000 20,000 – 26,000 Tenualosa ilisha, Harpodon nehereus,

Setipinna phasa, Trichiurus sp, Lates calcarifer, prawns

Godavari estuary 18,000 5,000 Mullets, prawns

Mahanadi estuary 30,000 550 Mullets, Lates calcarifer, Sciaenids,

prawns

Narmada estuary - 4,000 Hilsa, mullets, prawns

Peninsular estuaries - 2,000 Mullets, prawns, clupeids, crabs

Chilka lagoon 103,600 4,000 Prawns, mullets, catfishes, clupeids, perches, threadfins,

sciaenids

Pulicat lake 36,900 760-1370 Prawns, mullets, perches, crabs,

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clupeids

Vembanad lake and other backwaters of Kerala

50,000 14,000-17,000 Prawns, mullets, Lates calcarifer,

Etroplus suratensis, Chanos chanos

Estuarine wetlands (bheries)

42,600 37,500 Prawns, mullets, tilapia, Lates

calcarifer

Mangroves 356,500 - -

Lagoons and backwaters

Lagoons and backwaters associated with estuaries constitute an important inland capture fishery resource. Chilka and Pulicat Lake in the east coast and the Vembanad lagoon in the west coast are the major brackish water lakes in India. Regulated discharge through incoming rivers, siltation and anthropogenic pressure has made considerable negative impact on the fishery of Chilka Lake. On account of siltation, the lake area has shrunk from 906 km2 in 1965 to 620 km2 in 1995. There has been a qualitative and quantitative decline in fisheries. Total fish landing has decreased from 4,243 t in 1990 to 1270 t in 1995. Prawn catch has reduced from 28% to 14% during the same period. As fish catch from Pulicat lagoon is dependent on the ingress of fish and prawn seed from the sea, the sand bar formed at the mouth adversely affects recruitment. The production is reported to have dropped from 2,600 t during 1945-46, less than 1,000 t at present. In Vembanad backwaters, marked decline in prawn catches, both from impoundments and open waters has been reported due to human intervention, mainly pollution and over fishing (Menon et al., 2000).

Mangroves

Mangroves are biologically sensitive ecosystems, which play a vital role in breeding and nursery phases of many riverine and marine organisms of commercial value, besides contributing through its own fishery. However, since mangroves are protected areas where fishing is either prohibited or done on a subsistence basis, details of fish production in these water bodies are not available. Nearly 85% of the Indian mangroves are situated in the Sundarbans in West Bengal and Bay of Bengal islands. The Indian share of Sundarbans, which once covered an area of 4,262 km2, has now shrunken to 3,560 km2. Even this is under stress.

Fisheries enhancement in open waters

Although the breakup of catch from rivers, lakes, floodplain wetlands and reservoirs are not recorded, it is generally believed that the capture fisheries of rivers and estuaries contribute very little to the total inland catch. Bulk of production from open waters emanates from large reservoirs, small irrigation impoundments and floodplain wetlands through enhancement fisheries. The common enhancement practices followed in India are culture-based fisheries and stock enhancement. Apart from these, scope exists for other forms of enhancement such as ‘species enhancement’, ‘environmental enhancement’, ‘enhancement through new production systems’ and ‘integrated production systems’. At present, fisheries enhancement from different

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types of inland open water systems contributes upward of 1 million t to the total inland production. Enhancement fisheries is commonly followed in reservoirs and floodplain wetlands.

Reservoir fisheries

Reservoirs constitute ‘the’ prime inland fisheries resource of India due to the magnitude of resource size and the large unused production potential they hold. In the backdrop of (a) marine capture fisheries fast approaching a plateau (b) inland aquatic ecosystems like rivers facing degradation due to anthropogenic habitat changes and (c) the aquaculture development projects being capital intensive and subject to many environmental risks; reservoirs have become the focus of future fisheries development plans in India. Thus, national efforts to enhance fish production from India must rely heavily on reservoirs. In 1995, the country had 19,370 reservoirs, covering more than 3.15 million ha of reservoirs, which included 1,485,557 ha of small, 527,541 ha of medium and 1,140,268 ha of large reservoirs. There is no reliable data on the present status of reservoir area. CWC (2016) and Sarkar & Mishal (2017) reported that the present area is 3.51. However, this is subject to verification through collection and compiling data from states (Table 5).

Table 5 Reservoir resources of India

Size Area (ha) in 1995* Present estimated

area (ha)**

Small 1,485,557 Not known

Medium 527,541 Not known

Large 1,140,268 Not known

Total 31,53,366 3,510,000

* Sugunan (1995) ** Sarkar and Mishal, 2017)

Culture based fisheries is practiced in small reservoirs where the most of the stocked fishes are harvested annually. This ‘stocking and recapture’ system is very effective often leading to high yield rates up to 2000 kg/ha. But it can be practiced only in shallow reservoirs where easy harvesting of stocked fishes are possible. Conversely, the medium and large reservoirs are managed on the basis of stock enhancement (enhanced capture fisheries). Here the aim of stocking is establishing self-recruiting stocks to support a sustainable fishery. A number of measures such as conservation of environment for maintain a healthy natural food chain, protection of brood stock and breeding grounds and regulated deployment of fishing effort are required for practicing enhanced capture fisheries.

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Fish production trends and potential

Average production from Indian reservoirs is very low 10 – 20 kg/ha, compared to many other countries in the world. China- the world leader in reservoir fisheries- records a mean yield of 743 kg/ha from its reservoirs (De Silva, 2003) and those from Sri Lanka (>300 kg/ha) and Cuba (>100 kg/ha) are also high yielding (Sugunan, 2011). Similarly, some well managed beels of West Bengal, where fisheries is managed on the basis of stocking and recapture, have recorded yields up to 2000 kg/ha/year. These indicate the high untapped fish production potential that our reservoirs carry. Even if a modest increase the fish yield is achieved @ 500, 250 and 100 kg/ha for small, medium and large reservoirs, the reservoirs in India hold a production potential of 1.1 million t per year. We are utilizing less than 10% of the fish potential from reservoir fisheries (Table 6).

Table 6 Present and potential fish production from reservoirs

* Estimated ** Sugunan,1995 *** Sarkar et al., (2018) and Sharma et al., (2010) Enclosure culture Attempts to culture Indian carps in cages installed in reservoirs during the last few decades did not meet with any success. However, recently, after the Government of India granted permission to culture the exotic ‘pangas’, (Pangasianodon hypophthalmus), cage culture is becoming popular in reservoirs. Pangas is an air breathing catfish that can be stocked in cages at very high stocking density, giving high production rates. A 6m x 4m x 4m cage can produce 3 t pangas, but there are problems in marketing when produced in bulk. There is a need to develop proper post-harvest infrastructure and value chain to solve this problem. At present, pangas fish and its fillet cannot compete with the imported ‘basa’ in the domestic market. Although culture of fish in enclosures such as cages and pens installed in open water bodies offers scope for increasing production obviating the need for more land-based fish farms, mindless proliferation of this activity can lead to some very serious environmental and social problems. The main concerns are environmental degradation of reservoirs and escapement of exotic species into the main water body, apart from generating conflict with the traditional fishers who fish in open waters. Recognizing the importance of cage culture in inland open waters, a set of guidelines has

Category Present estimated area (ha)

Present yield in

1995 (kg/ha)**

Potential yield

(kg/ha)

Potential Production

(t)

Small *1649700 49.9 500 824850

Medium *596700 12.30 250 149175

Large *1263600 11.4 100 126360

Total ***3510000 15.0 - 1100385

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been developed by the Central Government, addressed to all stakeholders including, Farmers, SHGs, Cooperative Societies, other community organizations, Business process Development Facilitators (BDFs), Farmer Producer Organizations (FPOs), Fisheries Departments of the Indian States, Department of Fisheries, Government of India and its Institutes, Research Organizations and Environmentalists Government of India has issued guidelines for carrying capacity of cages and the species that can be used in cage culture in open waters (NFDB, 2016). Floodplain wetlands

Floodplain wetlands (beels) are wetlands associated with river floodplains, mostly cut-off river meanders with or without connection to the parent river. Spread over 3.54 lakh ha in eight States (Table 7), these water bodies are characterized by high organic productivity and accumulation of energy reserves at the detritus phase, enabling higher stocking densities as compared to their reservoir counterparts. Beels are also amenable to stocking of detritivorous fish species. Production levels of as much as 1,000-1,500 kg/ha/yr have been demonstrated in such waters in many parts of West Bengal through scientific management (Sugunan et al., 2000b). This needs to be scaled up to other parts of West Bengal and the states of Assam, Bihar and Uttar Pradesh. The major constraints in managing these resources for fisheries are degradation of wetland ecosystems for developmental activities that aggravates the problems of weed infestation and limit access and use of many types of fishing gear. Grow-out pen culture systems for carps have been very successful in the beels of Assam and West Bengal.

Table 7. Floodplain wetland resources in India

State Basin District Local names

Area (ha)

*Uttar Pradesh

Ghaghra, Tons, Yamuna, Gomti, Choti Sarju,Sarda, Ramganga, Chambal, Burhi Rapti

Ballia, Azamgarh, Mau, Basti, Deoria, Gorakhpur, Jaunpur,Rae Bareilly Pratapgarh, Allahabd, Barabanki, Sitapur, Unnao

Tal, Jheel 152000

Bihar Gandak, BurhiGandak, Lakhandei Baghmati- Adhwara, Kamla, Kosi

West Champaran, East Champaran, Muzaffarpur, Darbhanga, Sitamarhi, Madubani, Samastipur, Purnia, Saharsa, Begusarai, Khagaria, Monghyr

Maun, Chaur, Dhar

40000

West Bengal

Bhagirathi, Hooghly, Icchamati, Mayurakshi, Dharub, Dharla, Jalangi, Churni, Kalindi, Dharala, Pagla, Behula, Torsa,

Nadia, Murshidabad Burdwan, Maldah, 24 Parganas, Hooghly, Birbhum, Cooch Behar, Midnapur, Dinajpur

Beel, Charha,

42500

Baor

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Mahananda

Arunachal Pradesh

Kameng, Siang, Dibang, Dihang, Tirap, Lohit

East Kameng, Lower Subansiri, East Siang, Dibang valley, Lohit, Tirap

Beel 2500

Assam Lohit, Buhri dihing,

Dibru, Jhanji, Dikhow,Dimow, Manas, Kapili, Sonai, Pagladia, Dhansiri, Kakodanga, Kolong, Subansiri, Aai, Champabati, Kakodanga, Dibru, Dishang, Pontemeri Barak, Sonai, Sushma, Katakhal, Dholeswari, Longai, Rukni

Tinsukia, Dibrugarh, Sibsagar, Jorhat, Lakimpur, Golaghat, Dhemaji, Sonitpur, Darang, Nagaon, Morigaon, Nalbari, Kamrup Barpeta, Goalpara, Dhubri, Kokrajhar, Karimganj ,Hailakandi, Cachar

Beel 100000

Manipur Iral, Imphal, Thoubal Imphal, Thoubal, Bishunipur Pat 16500

Meghalaya Someshwari, Jinjiram Khasi hills, Garro hills Beel 213

Tripura Gomti, Manu, Khowai North Tripura, South Tripura, West Tripura

Beel 500

Total 354213

Compiled from Sugunan et al. (2000a); Sugunan et al.,, 2000b and *Pathak et al., (2004)

Challenges, opportunities and the way forward

The main challenge facing the inland fisheries development today is how to strike the

right balance between fish farming and conservation fisheries by synergizing activities related to capture fisheries, intensive aquaculture and enhancement fisheries. National policy should follow a middle path in terms of intensification and encourage enhancement wherever possible. The living aquatic resources, although renewable, are not infinite and need to be managed on a sustainable basis, if their contribution is to be harnessed for the nutritional, economic and social well-being of the growing population. However, in the enthusiasm to produce more fish from all available water bodies, many developing countries in the past paid higher attention to production and yield, while ignoring some key issues such as environmental sustainability and social equity. India is no exemption to this. However, awareness about environmental impact assessment, biodiversity conservation and environmental flows is increasing. A substantial section of the scientific community in the country and its civil society at large are now aware of and committed to achieving trade-off between sustainability and increased productivity. Development of

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intensive aquaculture and enhancement practices need to be viewed from conservation and socio-economic perspectives for achieving environmental sustainability and social equity.

There are several challenges that need to be addressed while trying to realize the production potential of the open water bodies and ensuring sustainable growth of aquaculture. Technologies used for developing capture fisheries and enhancements in open waters are relatively simple and do not demand very high technical skill. These can be applied by anybody with some basic management skill and normal intelligence. Still, the rate of adoption of scientific advice for open water fisheries, especially reservoir fisheries, is very low, and mostly these water bodies are still being managed on a very arbitrary manner, leading to low productivity and low sustainability. This can be attributed to lack of proper governance environments. The open water bodies in India are common property resources, generally managed based on community activity. Thus, organization of the community that manages the system plays a key role. There is also a social dimension of enhancement in the context of fisheries development. The profit obtained in aquaculture ventures accrues to an entrepreneur, investor or a small group of individuals as ‘return on investment’. On the contrary, the benefits due to increased fish production obtained in an enhancement fisheries (under a good governance regime), are shared by a large number of fishers- the key stakeholders. There is this large cake and each stakeholder gets a slice, albeit small. Thus, the enhancement provides opportunities for inclusive growth, which is economically sound and socially equitable. Coming to aquaculture, there is a glaring lack of a regulatory and advisory mechanisms on lines of CAA to inform, guide and regulate aquaculture practices including management of exotic species and following other norms of sustainability. Guidelines issued by the Central government from time to time are not implemented due to absence of a regulatory mechanism.

Opportunities and the way forward

The future strategy for inland fisheries development should center on the principle of

growth with sustainability. Sustainable development should be environmentally non-degrading, technically viable and socially acceptable. Sustainability, as applied to fisheries development is relevant to both capture and culture systems and their products, which are designed to maintain productivity and usefulness to society without any time limits (Gopalakrishnan, 1999). However, compared to the intensive aquaculture, capture and culture-based fisheries provide management options, which are more compliant with the norms of sustainable development. Sustainability of fish production systems is inversely proportional to intensification (Fig 3). Hyper-intensive culture systems are not environmentally sustainable and many times these work against social equity by affecting access to resources by many stakeholders.

Currently, the fish production in India is growing at the rate of 6% per annum. Various projections on demand for inland fish during 2021-22 range from 5.3 (ENCAP 2008, Paroda and Kumar, 2000) to 15.0 million t (www.nfdb.gov.in) It is now well accepted that the country can achieve 15 million t by 2021-22 as envisaged the Blue Revolution targets. But it is also obvious that any big increase in fish supply must come from the inland segment considering the slow growth of mariculture and the dwindling catch from marine capture. From 2009-10 to 2017-18, inland fish production increased by nearly three million tonnes. It is estimated that the current inland aquaculture production is about 7.75 million tonnes (7.00 t from fresh water aquaculture

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and 0.75 million from costal aquaculture). By 2020-21 it should touch at least 9 million mark (coastal aquaculture should reach 1 million and freshwater aquaculture should increase by 1 million t). It is pertinent to note that inland fisheries enhancement (and capture fisheries) accounted for only 1 million tonnes in 2016-17, which can be raised to touch 2 million. This is the way to achieve the Blue Revolution target of 15 million by 2021-22 (Fig 4).

While looking beyond 2020-21, maintaining the 6% growth for prolonged periods, say up to 2025-26, will bring in many new challenges. The land and water resources are becoming scarcer in the wake of increasing and often conflicting demands from various water and land use sectors and the problem is compounded by the climate change and environmental concerns. While it is unavoidable to practice intensive aquaculture in order to keep the pace of growth and to meet the future demands, it is equally important to ensure that all avenues for increasing production through more sustainable use of resources. Here comes the importance of enhancement fisheries. As culture-based fisheries and other forms of enhancement in reservoirs are a non-consumptive water use, it does not create any extra demand for water. Moreover, in the absence of feeding and chemical treatment, there is no chance for eutrophication and chemical pollution. It is necessary to utilize the opportunities for raising fish through culture-based fisheries, enhanced capture fisheries and sustainable cage culture in reservoirs. Prioritizing culture-based fisheries and other forms of enhancement from reservoirs holds the key for increasing inland fish production in India in a more sustainable way and reducing the necessity to depend heavily on unsustainable practices like high intensive aquaculture.

Conclusion

The national policy on inland fisheries should strike a balance between aquaculture and various enhancement practices to achieve higher fish productivity, environmental sustainability and social equity. There is a glaring lack of institutional mechanisms to ensure healthy growth of inland fisheries and aquaculture. Existing regulations on introduction of exotic fishes and sustainability norms are not implemented due to lack of regulatory arrangements. The inland open water fisheries is a complex mix of artisanal, subsistence and traditional fisheries with highly dispersed and unorganized marketing system. The tenure rights are archaic and inequitable. Capture and enhancement fisheries being common property regimes, the community is often not empowered to manage the ecosystem and fisheries on a sustainable and equitable manner. Appropriate policy level interventions are required to bring them under co-management platforms in order to enable and empower the community members to follow the norms. Often, it is not the complexity of technology that comes in the way of achieving higher production and maintaining sustainability in aquaculture and open water fisheries. It is the lack of appropriate community governance arrangement (for open water fisheries) and lack of institutional mechanisms to regulate the growth (in aquaculture) that lead to low productivity and sustainability.

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References / suggested reading Ayyappan, S. and Sugunan, V. V. (2009) Fishery resources in the context of nutritional security in

India. Indian Farming. 59 (7): 29 – 35

CSO-MFS (2011) Manual on Fishery Statistics-CSO-MFS http://mospi.nic.in/mospi_new/ upload/manual_fishery_statistics_2dec11.pdf

CWC (2016) National register of large dams. Central water commission. http://www.cwc.nic.in /main/ downloads/new%20nrld. Pdf

DAHD&F ( 2011) Annual Report 2010-11 http://dahd.nic.in/dahd/reports.aspx

De Silva Sena (2003) Culture-based fisheries: An underutilized opportunity in aquaculturen development. Aquaculture: 221 (1-4) 221-243

DoF (2018) Annual Report 2017-18, Department of Animal Husbandry, Dairying and Fisheries, Ministry of Agriculture, Government of India. 199 p

DoF (2019) Handbook on fisheries statistics. Government of India Ministry of Fisheries, Animal Husbandry and Dairying Department of Fisheries Krishi Bhavan, New Delhi. 175 p

ENCAP (2008) Exploring market opportunities for fisheries sector in India. National Centre for Agricultural Economics and Policy Research (ICAR) New Delhi. 426 p

Gopalakrishnan, V. (1999) Fisheries of estuaries and coastal lagoons of India-Problems and solutions. Souvenir, Central Inland Capture Fisheries Research Institute Barrackpore 22- 23 December. 35 p

ICAR (2011) Handbook of fisheries and aquaculture, Indian Council of Agricultural Research, New Delhi. 1116p

Jhingran, A. G. (1988) A general review of the inland capture fisheries situation in India Souvenir Central Inland Capture Fisheries Research Institute 14-16 December 1988. 41 p

Jhingran, V.G. (1991) Fish and fisheries of India, Hindustan Publishing Corporation (India), Third Edition: 727p

Menon, N. N., Balchand, A. N. and Menon, N. R. (2000) Hydrobiology of the Cochin backwater system- a review. Hydrobiologia. 430: 149-183

NFDB (2016) Guidelines for cage culture in inland open water bodies in India. http://nfdb.gov.in/PDF/GUIDELINES/Guidelines%20for%20Cage%20Culture%20in%20 Inland%20Open%20Water%20Bodies%20of%20India.pdf

Paroda, R.S. and Kumar, P. (2000) Food production and demand in South Asia. Agriculture of Economic Research. 1-25

Pathak, V. (2000) Ecology and production dynamics of river Brahmaputra with special emphasis on its tributaries Bull. No.97 Central Inland Capture Fisheries Research Institute Barrackpore 743101 West Bengal India. 49 p

Pathak, V., Tyagi, R. K. and Balbir Singh. 2004. Ecological status and production dynamics of wetlands of Uttar Pradesh. Bull. No. 131. Central Inland Capture Fisheries Research Institute. 44 p

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Fisheries and Aquaculture (Mohanty et al., Eds.). Barrackpore, India: ICAR-Central Inland Fisheries Research Institute

Sarkar, U. K., Sandhya, K. M., Mishal, P., Karnatak, G., Lianthuamluaia, Kumari, S., Panikkar, P., Palaniswamy, R., Karthikeyan, M., SibinaMol, S., Paul, T. T., Ramya, V. L., Rao, D. S. K., Feroz K. M., Panda, D. and B. K. Das. (2018) Status, Prospects, Threats, and the Way Forward for Sustainable Management and Enhancement of the Tropical Indian Reservoir Fisheries: An Overview, Reviews in Fisheries Science & Aquaculture. 26:2, 155-175, DOI: 10.1080/23308249.2017.1373744

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Sugunan, V. V. (2011) Reservoir Fisheries (Ayyappan, Ed.), Indian Council of Agricultural Research Krishi Anusandhan Bhavan, New Delhi India. pp 238-274

Sugunan, V. V., Bhattacharjya, B. K. and P. K. Saha (2000a) Ecology and Fisheries of beels in Assam. Bull. No. 104, Central Inland Capture Fisheries Research Institute, Barrackpore. 65 p

Sugunan, V. V., Vinci, G. K., B. K. Bhattacharjya and M. A. Hassan (2000b) Ecology and fisheries of beels in West Bengal. Bull. No. 103, Central Inland Capture Fisheries Research Institute, Barrackpore. 53 p

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FAO Code of Conduct for Responsible Fisheries - Fishing Operations

M.R. Boopendranath Principal Scientist - Retd., Fishing Technology Division, ICAR-CIFT, Kochi


Introduction

Introduction of powerful and highly efficient fish harvesting systems and fish detection methods and an uncontrolled expansion in fleet size fuelled by ever increasing market demand for fish brought about increasing pressure on the world fishery resources. Unmistakable signs of overfishing and negative impacts on the ecosystems have increasingly manifested in the recent years, highlighting the need for scientific management of the world fishery resources in order to ensure their long-term sustainability and availability to the future generations.

It is estimated that, in 2015, about 59.9% of the fish stocks monitored by FAO were fully exploited, 33.1% over-exploited, and only 7% were under-fished (FAO, 2018) (Fig. 1). The percentage of stocks that are fished at biologically unsustainable levels increased from 10% in 1974 to 33.1% in 2015. Overfishing and irresponsible fishing practices have long been recognized as leading causes that have reduced biodiversity, modified ecosystem functioning and stock collapses (FAO, 1995; Jackson et al., 2001; Lotze et al., 2006; Worm et al., 2006). Fishing down effect is pervasive in world fisheries, including Indian fisheries (Pauly et al., 2003; Pauly and Maclean, 2003; Vivekanandan et al., 2005; Bhathal, 2005; Bhathal and Pauly, 2008; Worm et al., 2006) (Fig. 2 and 3). Analysis of data from five ocean basins revealed 90% decline in numbers of large predatory fishes (tuna, blue marlins, swordfish and others) since the advent of industrialized fishing (Myers and Worm, 2003). Removal of excess fishing capacity and adoption of responsible fishing gear and practices and a conducive fisheries management regime would contribute to the long-term sustainability of the resources, minimise negative environmental impacts, protect biodiversity and facilitate rebuilding of the depleted marine fish stocks (Worm et al., 2009). Estimated excess capacity in Indian fisheries is shown in Fig. 4. A recent UNEP green economy report on fisheries suggests that investing to achieve sustainable levels of fishing by strengthening fisheries management and financing a reduction of excess capacity through de-commissioning vessels and equitably relocating employment in order to rebuild overfished and depleted fish stocks could result in an increase in the marine fish landings in the long run, despite a drop in the next decade as stocks recover (UNEP, 2011). The present value of benefits from greening the fishing sector is about 3 to 5 times of the necessary additional costs.

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Fig. 1. Status of marine fish stocks (%) during 2015 (Source: FAO, 2018)

Fig. 2. Trends in mean trophic level of landings in India from 1950 to 2000 (Source: Bhathal and Pauly, 2008)

Fig. 3. Global loss of species from large marine ecosystems (LMEs) - Trajectories of

collapsed fish and invertebrate taxa over the past 50 years (Source: Worm et al., 2006)

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Fig. 4. Excess fishing capacity in capture fisheries

The FAO Code of Conduct for Responsible Fisheries

Adoption of the United Nations Convention on the Law of the Sea in 1982 brought the exclusive rights and responsibilities for the management of the resources in the Exclusive Economic Zones (EEZs) to the coastal States. EEZs extending to 200 nautical miles from the coastline encompass 90 percent of the world fishery resources. In 1992, based on the evaluation of the state of world fisheries, FAO Committee on Fisheries recommended for the development of concepts which would lead to the responsible fishery development. The international Conference on Responsible Fishing, held in the same year at Cancun, Mexico highlighted the need for an International Code of Conduct for Responsible Fisheries. Subsequent efforts in this direction have resulted in the adoption of Code of Conduct for Responsible Fisheries (CCRF), by FAO Conference in October 1995 (FAO, 1995; FAO, 2011a). The Code categorically stipulates that the right to fish carries with it the obligation to do so in a responsible manner so as to ensure effective conservation and management of the living aquatic resources.

The CCRF is voluntary and global in scope and generic in nature. It sets out the principles and international standards of behaviour for responsible practices to ensure long term sustainability of living aquatic resources, with due respect for the ecosystem, biodiversity and environment. It covers conservation; management and development of fisheries; capture, processing and trade of fish and fishery products; aquaculture; fisheries research; and integration of fisheries into coastal area management. The code recognizes the nutritional, economic, environmental and cultural importance of fisheries and the interests of all those concerned with fishery sector. The Code was adopted by FAO after extended deliberations and discussions in various fora, on 31 October 1995. Although it is voluntary, it is expected that its provisions will

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increasingly be applied to world fisheries. The Code is the first international instrument of its type to have been developed for fisheries (FAO, 2009).

The key principles of the Code include (i) management of stocks using the best available science; (ii) application of the “precautionary principle,” using conservative management approaches when the effects of fishing practices are uncertain; (iii) avoiding overfishing and preventing or eliminating excess fishing capacity; (iv) minimisation of bycatch and discards; (v) prohibition of destructive fishing methods; (v) restoration of depleted fish stocks; (vi) implementation of appropriate national laws, management plans, and means of enforcement; (vii) monitoring the effects of fishing on the ecosystem; (viii) working cooperatively with other states to coordinate management policies and enforcement actions; (ix) recognizing the importance of artisanal and small-scale fisheries, and the value of traditional management practices. There is now broad agreement at the international policy level that the ecosystem approach to fisheries which is consistent with the FAO Code of Conduct for Responsible Fisheries is the appropriate and necessary framework for fisheries management (FAO, 2009b. The ecosystem approach to fisheries strives to balance diverse societal objectives, by taking into account the knowledge and uncertainties of biotic, abiotic and human components of ecosystems and their interactions and applying an integrated approach to fisheries within ecologically meaningful boundaries. The greatest benefit of the adoption and implementation of the Code is that it will facilitate the conservation of fisheries for future generations. It will help fishermen to avoid resource and energy waste, give industry the power and opportunity to solve problems that threaten their livelihood and way of life, leading to reduced costs and higher returns. The Code consists of five introductory articles followed by seven articles of more specific nature:

i. Nature and scope of code

ii. Objectives of the code

iii. Relationship with other international instruments

iv. Implementation, monitoring and updating

v. Special requirements of developing countries

vi. General principles

vii. Fisheries management

viii. Fishing operations

ix. Aquaculture development

x. Integration of fisheries into coastal area development

xi. Post-harvest practices and trade

xii. Fisheries research

Articles contained in the Code of Conduct of Responsible Fisheries are further elaborated by FAO in Technical Guidelines to interpret the Code with greater specificity and provide practical advice on implementing the provisions. FAO has brought out 27 Technical Guidelines in areas such as (i) Integration of Fisheries into coastal area management, (ii) Precautionary approach to capture fisheries and species introductions, (iii) Fishing operations, (iv) Inland fisheries, (v) Aquaculture development, (vi) Fisheries management, (vi) Responsible fish utilization, (vii) Indicators for

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sustainable development of marine capture fisheries, (viii) Implementation of the International Plan of Action to deter, prevent and eliminate, illegal, unreported and unregulated fishing, (ix) Increasing the contribution of small-scale fisheries to poverty alleviation and food security, (x) Health management for responsible movement of live aquatic animals, (xi) Information and knowledge sharing, (xii) Responsible fish trade and (xiii) Marine protected areas and fisheries, (xiv) Precautionary approach to capture fisheries and species introductions.

FAO Technical Guidelines on fisheries management and responsible fishing

In areas pertaining to fisheries management and fishing operations, FAO has issued Technical Guidelines on fisheries management (FAO, 1997a; 2000; 2003; 2008a; 2008b; 2009a; 2011b), fishing operations (FAO, 1996a), Vessel Monitoring Systems (FAO, 1998), best practices to reduce incidental catch of seabirds in capture fisheries (FAO, 2009b), implementation of the International Plan of Action to deter, prevent and eliminate, illegal, unreported and unregulated fishing (FAO, 2001; 2002), increasing the contribution of small-scale fisheries to poverty alleviation and food security (FAO, 2005), information and knowledge sharing (FAO, 2009c), inland fisheries (FAO, 1997b; 2008c), integration of fisheries into coastal area management (FAO, 1996b); precautionary approach to capture fisheries and species introductions (FAO, 1996c) and on best practices to improve safety at sea (FAO, 2015). The Code places a strong emphasis on supporting developing countries in their efforts to implementing the Code, as they are the custodians of the largest share of world fisheries resources.

International Plans of Action (IPOAs)

The International Plans of Action (IPOAs) are voluntary instruments elaborated within the framework of the Code of Conduct for Responsible Fisheries. The IPOAs pertaining to fishing operations, developed to date and their year adoption is given below:

International Plan of Action for Reducing Incidental Catch of Seabirds in Longline

Fisheries (IPOA-Seabirds 1999)(FAO, 1999; FAO, 2009b)

International Plan of Action for Conservation and Management of Sharks (IPOA-Sharks

1999)(FAO, 1999)

International Plan of Action for the Management of Fishing Capacity (IPOA- Capacity

1999)(FAO, 1999)

International Plan of Action to Prevent, Deter, and Eliminate Illegal, Unreported and

Unregulated Fishing (IPOA-IUU 2001)(FAO, 2001)

Article 8 of CCRF: Fishing operations

Article 8 in the Code of Conduct of Responsible Fisheries is elaborated in FAO Technical Guidelines for Responsible Fisheries 1: Fishing Operations (FAO, 1996a). Article 8 contains 11 Sections and 52 sub-sections dealing with the Code of Conduct for Responsible Fishing Operations. Code of conduct for responsible fishing operations is a new approach to fisheries which will help fishing industry in their efforts to make harvesting operations responsible and sustainable. It provides operational standards and practical directions for all persons involved in

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commercial fishing operations. The Article 8 include Sections (8.1) Duties of all states, (8.2) Flag State duties, (8.3) Port State duties, (8.4) Fishing operations, (8.5) Fishing gear selectivity, (8.6) Energy optimization, (8.7) Protection of aquatic environment, (8.8) Protection of the atmosphere, 8.9) Harbours and landing places for fishing vessels, (8.10) Abandonment of structures and other materials, and (8.11) Artificial reefs and fish aggregation devices. Salient provisions of Article 8 of the Code include the following:

Responsibilities of all States

Provide conditions that ensure responsible fishing.

Ensure fishing is conducted only by units having authorization to fish; maintain and

update records of authorizations with all relevant details and conditions such as

permitted fishing areas, seasons and types of fishing gear.

Develop and maintain fisheries statistical information system.

Establish a system of Monitoring, Control and Surveillance (MCS) system and law

enforcement.

Establish systems for appropriate education, training and certification for those engaged

in fishing operations

Ensure adoption of minimum health and safety standards, as per relevant international

agreements.

Establish Search and Rescue (SAR) systems, IMO Global Maritime Distress and Safety

System (GMDSS), communication systems, forecasting and broadcasting of information on

the weather and sea conditions.

Ensure that new fish harvesting systems are cleared through an environmental impact

analysis, prior to its introduction into a fishing area.

Develop and adopt standards for energy optimization and saving in fisheries.

Phase out the use of Chloroflurocarbon (CFC) in refrigeration systems and Halon in fire

extinguishing systems.

Ensure selective fishing gear and practices are adopted.

Regulate transshipment of fish and fishery products at sea.

Promote adoption of appropriate technology to ensure quality of retained catch.

Develop institutional framework, standards and guidelines for site selection, design,

construction, maintenance and management of fisheries harbours and landing places.

Develop policies and management systems for enhancing stock and fishing opportunities

through the use of Artificial Reefs and Fish Aggregating Devices

Establish management policies taking into account small-scale fisheries, preferably in

consultation with concerned fishing communities

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Guarantee the fishing rights of small-scale fishermen and act to limit conflict with other

fisheries, large-scale fisheries in particular

Responsibilities of Flag States

Maintain records of all fishing vessels entitled to fly the flag and authorized to fish, with

all relevant details.

Ensure vessels conducting operations in high seas and in waters under jurisdiction of

other States follow internationally agreed codes of practices and carry documents such as

Certificate of Registry and authorization to fish issued by competent authorities.

Ensure fishing vessels are maintained in accordance with national rules and international

conventions

Ensure fishing vessels keep appropriate fishing and navigation logs and vessel position

reporting systems.

Ensure fishing vessels and gears are marked according to standard marking systems.

Ensure adoption of safety standards.

Ensure fishing vessels are manned by trained, experienced and certified crew.

Ensure proper insurance coverage for the crew and potential operational hazards.

Ensure repatriation of crew, when appropriate.

Ensure details of accidents at sea are reported to the concerned authorities.

Responsibilities of Port States

Provide assistance to a foreign flag State as per procedures established in accordance

with international laws and applicable international agreements.

Ensure inspection of documentation required on board fishing vessels.

Detention of vessel which do not fulfil commitments and reporting of deficiencies.

Responsibilities of fishing industry

Carry all relevant documents onboard including authorization to fish.

Ensure insurance coverage.

Ensure that fishing is conducted with due respect for existing regulations for safety,

prevention of collision at sea and protection of marine environment.

Ensure that the use destructive fishing practices such as dynamiting and poisoning are

prohibited.

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Ensure that documentation regarding details of fishing operations, retained and discarded

species are maintained and reported systematically to appropriate agencies to facilitate

analysis and management actions.

Adopt appropriate technology to ensure the quality of retained catch.

Encourage the development and use of selective fishing gear and practices.

Adopt technologies to minimize the impact due to ghost fishing by lost and abandoned

fishing gear.

Adopt practices and equipment to enhance energy optimization

Adopt practices and equipment to reduce the emissions of dangerous substances to the

atmosphere.

Follow relevant MARPOL regulations to protect aquatic environment.

Responsibilities of R&D organizations

Develop more selective fishing systems and practices.

Standardize methodology for determination of fishing gear selectivity.

Develop of energy efficient fishing systems.

Develop of environment friendly fishing systems.

Conduct environmental audit.

Provide research inputs needed for sustainable fisheries management.

Disseminate information on research products, facilitating responsible fishing.

Technologies for responsible fishing

Directions associated with use and development of fishing gear and practices delineated in the Code focus on (i) selective fishing gear and practices, (ii) environment-friendly fishing gears and (iii) energy conservation in harvesting (FAO, 1995; 1996a). General principles set out in Article 6 of the Code, prescribe that overfishing and excess fishing capacity should be prevented; fishing capacity should be commensurate with the maximum sustainable yield of the resources; effort must be taken to rehabilitate the resources where appropriate; and that selective and environmentally safe fishing gear and practices should be further developed and applied, in order to conserve resources and protect biodiversity and minimise waste and impact on associated or dependent species.

Article 8 of the Code of Conduct for Responsible Fisheries which covers Fishing Operations and Article 12 on Fisheries Research have a number of provisions which are of direct relevance to the fishing gear research, design, development and operations. Section 8.4 on Fishing operations, seek to prohibit destructive fishing practices such as dynamiting and poisoning; discourage fishing gear and practices that lead to catch discards; promote the fishing gear and practices that are selective and increase survival rates of escaping fish; minimise loss of fishing gear and ghost fishing effects of lost and abandoned fishing gear through development of

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technologies, materials and operational methods; and ensure environmental impact assessment prior to the introduction of new fishing gear and practices to an area.

Section 8.5 on Fishing gear selectivity, seek to promote development and wide spread adoption of fishing gear and methods which would minimise waste, discards, catch of non-target species. Article 12 on Fisheries Research, also seek to ensure investigations on selectivity of fishing gear, the environmental impact of fishing on target species and behaviour of target and non-target species in relation to fishing gears as an aid to management decisions and with a view to minimise non-utilised catch as well as safeguarding biodiversity of ecosystem; to ensure that before commercial introduction of new types of gear, a scientific evaluation of their impact on fisheries and ecosystem in the area of their intended use is undertaken.

Section 8.6 on Energy optimisation, seek to promote appropriate standards, guidelines and practices which would lead to efficient use of energy in harvest and post-harvest activities. Section 8.11 on Artificial reef and fish aggregation devices seeks to promote the development and use of artificial reef and fish aggregation devices where appropriate for increasing stock size and enhancing fishing opportunities.

Technologies for responsible fishing are generally oriented towards reducing bycatch of non-target species; Endangered, Threatened or Protected (ETP) species and juveniles; minimising the environmental impact of fishing gear and their operation and minimising the energy use per unit volume of fish landed, during fishing operations (Prado, 1993; Valdemarsen and Suuronen, 2003; Boopendranath, 2007; 2009; 2012; CIFT, 2007; Eayrs, 2007; Valdemarsen et al., 2007; Boopendranath et al., 2008; 2010; Kennelly, 2007; Suuronen et al., 2012; Edwin, 2018 and others)

Conclusion

FAO Code of Conduct for Responsible Fisheries provides the following pointers for sustainable fisheries development:

Evolve regionalized consensus Code of Conduct for Responsible Fishing, in close

participation with all stake holders (traditional, motorized and mechanized fishermen

organizations), fisheries research organizations and fisheries managers.

Maintain registry of all fishing vessels in waters under State jurisdiction with all essential

details.

Take measures to control open access by strict enforcement of a system of licenses

(authorization to fish) in traditional, motorized and mechanized sectors.

Periodically revalidate maximum sustainable yield of resources in the existing fishing

grounds and determine fishing units of specific capacity in each category, for sustainable

harvesting of resources.

Standardise the capacities, dimensions and specifications of fishing units in each category.

Address the question of excess capacity squarely and take steps to remove excess capacity

over a time schedule.

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Identify and delimit Protected Areas in marine and inland water ecosystems.

Conduct periodic audit of fishing craft and gear combinations, their economics of

operation, ecological and environmental impacts.

Evolve regulations for mandatory survey of mechanized fishing vessels.

Evolve a system for marking fishing vessels and fishing gears.

Evolve regulations and promote use of life saving, fire fighting and communication

equipment for safety of fishermen.

Evolve regulations for mandatory survey of mechanized fishing vessels.

Promote selective fishing gear and practices.

Develop and implement National Plans of Action (NPOAs) for (i) management of fishing

capacity, (ii) prevention of illegal, unreported and unregulated (IUU) fishing, (iii)

conservation and management of sharks, and (iv) reducing incidental catch of seabirds in

long line fisheries.

Evolve an efficient Monitoring, Control and Surveillance (MCS) system.

Make effective use of Geographical Information System for fisheries management;

monitoring and control of fishing effort and energy use.

Evolve and promote a package of practices for energy conservation in fish harvesting.

Develop a Fisheries Information Portal for providing easy access to authentic information

and facilitating fisheries research, management and business.

Evolve a mandatory programme of training and certification for non-motorised,

motorised and mechanised fishermen in safe navigation, responsible fishing, log keeping

and reporting.

A wide range of proven technologies are readily available for adoption under the responsible fishing regime, in the areas of bycatch reduction, mitigation of negative environmental impacts and conservation of energy in fishing. A rights based regulated access system based on a strong inclusive participatory management seems to be necessary for facilitating large scale adoption of responsible fishing technologies.

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Bhathal, B. and Pauly, D. (2008) Fishing down marine food webs' and spatial expansion of coastal fisheries in India, 1950-2000. Fish. Res. 91: 26-34

Boopendranath, M.R. (2007) Possibilities for bycatch reduction from trawlers in India. In: K.K. Vijayan, P. Jayasankar and P. Vijayagopal (Eds) Indian Fisheries – A Progressive Outlook, Central Marine Fisheries Research Institute, Cochin. pp 12-29

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Boopendranath, M.R. (2009) Responsible fishing operations, In: Handbook of Fishing Technology (Meenakumari, B., Boopendranath, M.R., Pravin, P., Thomas, S.N. and Edwin, L., Eds), Central Institute of Fisheries Technology, Cochin. pp 259-295

Boopendranath, M.R. (2012) Technologies for responsible fishing, In: Advances in Harvest and Post-harvest Technology of Fish (Nambudiri, D.D. and Peter, K.V., Eds.), Chapter 2, pp. 21-47, New India Publishing Agency, New Delhi

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Valdemarsen, J.W., Jorgensen, T. and Engas, A. (2007) Options to mitigate bottom habitat impact of dragged gears, FAO Fisheries Technical Paper No. 506, FAO, Rome. 29 p

Vivekanandan, E., Srinath, M., Kuriakose, S., (2005) Fishing the marine food web along the Indian coast. Fisheries Research 72: 241-252

Worm, B., Barbier, E.B., Beaumont, N., Duffy, J.E., Folke, C., Halpern, B.S., Jackson, J.B.C., Lotze, H.K., Micheli, F., Palumbi, S.R., Sala, E., Selkoe, K.A., Stachowicz, J.J., Watson, R. (2006) Impacts of Biodiversity Loss on Ocean Ecosystem Services. Science 314: 787-760

Worm, B., Hilborn, R., Baum, J.K., Branch, T.A., Collie, J.S., Costello, C., Fogarty, M.J., Fulton, E.A., Hutchings, J.A., Jennings, S., Jensen, O.P., Lotze, H.K., Mace, P.A., McClanahan, T.R., Minto, C., Palumbi, S.R., Parma, A.M., Ricard, D., Rosenberg, A.A., Watson, R., Zeller, D. (2009) Rebuilding global fisheries. Science 325: 578-585

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Netting Materials for Fishing Gear with Special Reference to Resource Conservation and Energy Saving

Saly N Thomas* and Sandhya K. M Fishing Technology Division, ICAR-Central Institute of Fisheries Technology, Kochi

*E-mail: [email protected] Introduction

Netting yarns/twines forms the main part of majority of fishing gears. Apart from giving structure and shape to the gear, materials play a substantial role in resource and energy conservation. Netting materials for fabrication of fishing gear are either of textile or non-textile origin. Textile materials comprise of netting, twine and rope while floats, sinkers, hooks etc constitute non-textile origin materials. The raw material for fish netting consists of fibres which can be distinguished into two groups: natural fibres and man-made fibres. Different kinds of fibres originating from plant and animal body parts have been used for production of textiles and other products are termed as natural fibres. Traditional fishing gears used earlier, till 1950s were mainly with natural fibres such as cotton, manila, sisal, jute and coir.

Like elsewhere in the world, in India too, with the introduction of man-made synthetic fibres in the late 1950s, natural fibres used for the fishing gears have been substituted by these synthetic materials. This transition was mainly due to the highly positive properties of these fibres such as highly non-biodegradable nature, high breaking strength, better uniformity in characteristics, high abrasion resistance, low maintenance cost and long service life. Earlier, nettings used to be fabricated manually, which is laborious and time consuming while the introduction of synthetic fibres paved way for machine made nettings which revolutionized the fishing industry. Basic terms in netting Fibre: The basic material of netting, has length at least 100 times its diameter. Netting yarn: is the standardized universal term for all textile material which is suitable for manufacture of netting for fishing gears and which can be knitted into netting by machine or by hand without having to undergo further process. Yarn is made into a netting by twisting or braiding. Monofilaments are used directly for making into netting without further process. Netting twine: or folded yarn is a netting yarn which is made of two or more single yarns or monofilaments. Cabled netting twine: Combines two or more netting twines by one or two further twisting operations. Fibres are combined to form single yarns. Several single yarns are twisted together to form a netting twine. Several of these folded yarns or netting twines are twisted together by a secondary twisting operation to form a cabled netting twine. Braided netting yarns: These are produced by interlacing a number of strands in such a way

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that they cross each other in diagonal direction. These braids are usually in the form of tubes. The braided netting yarns are available with or without core. Core is the term used for single yarn, twisted yarn or monofilaments which do not belong to the braided tube but fills the space inside the tube. Netting: Netting is defined by International Organization for Standardization (ISO) as a meshed structure of indefinite shape & size, composed of one yarn or one or more systems of yarns inter laced or joined or obtained by other means for example by stamping or cutting from sheet material or by extrusion Natural Fibres: Fibres of plant origin such as that of cotton, manila, sisal, hemp, linen, ramie, coir etc. and of animal origin such as silk, hair etc are termed as natural fibres. As far as the fishing industry is concerned, the plant/vegetable fibres are better suited for the fabrication of fishing gear than animal fibres which are too expensive. Based on the source of origin, vegetable fibres come as seed fibre, fruit fibre, leaf fibre and bast fibre. Seed fibre is available from cotton (Gossipium sp.) while coir (Cocos nucifera) is a source of fruit fibre. Sisal (Agave sisalana), Abaca/Manila (Musa textiles) and pineapple leaf (Ananas comosus) are sources of leaf fibre. Examples of bastfibres are True hemp (Cannabis sativa), Indian hemp (Crotalaria juncea) and jute (Corchorus capsularis).

While eco-friendliness and reasonable weather resistance are positive attributes for natural fibres, the high biodegradability (being cellulose in origin) and very short useful life time, when exposed to water, are negative attributes of natural fibres. To increase the service life, frequent preservation and protection measures are required which limit the effective and continued use of natural fibres in different fishing seasons. Moreover, on wetting, natural fibres absorb water and swell resulting in increased thickness, bulkiness and weight which limit the size of gear that can be handled from a boat. Man-made fibres: Natural polymers and synthetic polymers constitute man-made fibres. Natural polymers are manufactured by the alteration of natural polymers like cellulose and protein while synthetic polymers are obtained by synthesis or chemical process. Man-made fibres derived from cellulose eg: rayon, are susceptible to microbial deterioration while synthetic fibres are very resistant to biodeterioration.

Synthetic fibres have greatly extended the endurance of fishing gears, and together with mechanized vessels, have increased the size and complexity of nets. It is stated that synthetic fibres brought to one of man’s oldest occupations, the miracle of science and in doing so provide easier living for the fishers. The development of synthetic fibre was based on the discovery that all fibre materials consist of long chain molecules in which a great number of equal simple units are linked together. This structure gives the fibre the properties required for a textile fibre. Synthetic fibres are produced entirely by chemical process or synthesis from simple basic substances such as phenol, benzene, acetylene etc. The chemical process involves the production of macromolecular compounds by polycondensation or polymerization of simple molecules of a monomer. The raw materials are petroleum, coal, coke and hydrocarbon. Depending on the type of polymer, synthetic fibres are classified into different groups and are known by different names in different countries.

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Altogether seven groups of polymers are developed; most important polymer/synthetic fibres used in fishing gears are polyamide (PA), polyester (PES), polyethylene (PE) and polypropylene (PP). Other synthetic fibres, which are less widely used and generally restricted to Japanese fisheries, are polyvinyl alcohol (PVAA), polyvinyl chloride (PVC) and polyvinylidene chloride (PVD). Aramid fibres, Ultra high molecular weight polyethylene (UHMWPE) and liquid crystal polymer are later additions to this group.

Polyamide (PA): Polyamide, a synthetic polymer, popularly known as nylon, invented in 1935 refers to a family of polymers called linear polyamides. Nylon consists of repeating units of amide with peptide linkages between them. Depending on the raw material and method of making two types of nylon viz., PA 6 and PA 66 are available for fibre applications. PA 66, widely used for fibres is made from adipic acid and hexamethylene diamine while PA 6 is built with caprolactam. With regard to the fisheries, there is no difference between PA 66 and PA 6, while in India, for fishing purposes PA 6 is used. The softness, lightness, elastic recovery, stretchability and high abrasion and temperature resistance are superior properties inherent to nylon. However, high moisture absorption along with dimensional instability and requirement of UV stabilization are its disadvantages. On wetting, nylon loses up to 30% of tensile strength and 50% of tensile modulus. Polyolefines: Polypropylene (PP) and Polyethylene (PE) are often collectively called "polyolefines". Polyolefin fibres are long-chain polymers composed (at least 85% by weight) of ethylene, propylene or other olefin units. Polyolefin fibres are made by melt spinning. They do not absorb moisture and have a high resistance to UV degradation. • Polyethylene (PE): PE fibre is defined as: “fibres composed of linear macromolecules made

up of saturated aliphatic hydrocarbons”. PE fibres, used for fishing gear, are produced by a method developed by Ziegler, in the early 1950s.The monomer ethylene, the basic substance of polyethylene, is normally obtained by cracking petroleum. Linear polyethylene or high-density polyethylene has high crystallinity, melting temperature, hardness and tensile strength. In India, PE is used for manufacture of netting and ropes.

• Polypropylene (PP): PP fibre is defined as: “fibres composed of linear macromolecules made

up of saturated aliphatic carbon units in which one carbon atom in two carries a methyl side group”. This is an additive polymer of propylene. PP was commercialized in 1956 by polymerizing propylene using catalysis. Though PP netting and ropes are available, in India, PP is mainly used for ropes.

• Polyester (PES): The principal PES fibres are made from polymerization of terepthalic acid

and ethylene alcohol. It was first synthesized by Whinfield and Dickson of Great Britain in 1940-41 and named the fibre "Terylene”.

Later introductions

Introduction of synthetic materials with high tensile strength properties has made it possible to bring out changes in the design and size of fishing nets. As the fishing industry became highly competitive, the search and research for new generation materials which give better

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strength for less thickness resulted in invention of new materials. Aramid fibres, Kevlar, UHMWPE, biodegradable plastic etc are recent introductions to the fishing gear material sector. These materials have advantages, especially less drag which results in fuel efficiency. The performance of UHMWPE webbing and rope in the Indian context is being studied by ICAR-CIFT. Aramid fibres: Aramid fibres are fibres in which the base material is a long-chain synthetic polyamide in which at least 85% of the amide linkages are attached directly to two aromatic rings. Two types of aramid fibres are produced by the DuPont Company: Kevlar (para-aramid) and Nomex (meta-aramid), which differ primarily in the substitution positions on the aromatic ring. Generally, aramid fibres have medium to very high tensile strength, medium to low elongation-to-break, and moderate to very high modulus. KEVLAR® polyphenylene terephthalamide (PPTA): A polymer containing aromatic and amide molecular groups is one of the most important man-made organic fibre ever developed. Because of its unique combination of properties, KEVLAR® is used in the fishing sector as netting, fishing rod and fishing line. Fibres of KEVLAR® consist of long molecular chains produced from poly (p-phenylene terephthalamide). The chains are highly oriented with strong interchain bonding, which result in a unique combination of properties. The strength to weight ratio of Kevlar is high; on a weight basis, it is five times as strong as steel and ten times as strong as aluminum. It has high tensile strength at low weight, low elongation to break, high toughness (work-to-break), and excellent dimensional stability. In sea water, ropes with KEVLAR® are upto 95% lighter than steel ropes of comparable strength. Ultra high molecular weight polyethylene(UHMWPE): UHMWPE is a type of polyolefin synthesized from monomer of ethylene processed by different methods such as compression molding, ram extrusion, gel spinning, and sintering. Polyethylene with an ultra high molecular weight (UHMWPE) is used as the starting material. In normal polyethylene, the molecules are not orientated and are easily torn apart. The fibres made by gel spinning have a high degree of molecular orientation with very high tensile strength. The fibre is made up of extremely long chains of polyethylene, which attains a parallel orientation > 95% and a level of crystallinity of up to 85%. The extremely long chains have molecular weight usually between 3.1 and 5.67 million while HDPE molecule has only 700 to 1,800 monomer units per molecule.

UHMWPE, also known as high modulus polyethylene (HMPE) or high performance polyethylene (HPPE) is a thermoplastic. It has extremely low moisture absorption, very low coefficient of friction, is self-lubricating and is highly resistant to abrasion (10 times more resistant to abrasion than carbon steel). This is available as Dyneema and Spectra produced by two different companies. Commercial grades of dyneema fibres SK 60 and SK 75 are specially designed for ropes, cordage, fisheries and textile applications. It can be made into microfilament braided twine of fine diameter. Nettings of simple knot, double knot and knotless are available. A comparison of properties of UHMWPE to other synthetic fibres is given in Table 1.

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Table 1. Comparative properties of synthetic fibres

Chemical/physical characteristics

Fibre PA 6 PA 66 PES PP PE Dyneema

SK75 Tenacity (g/den) 9 9 9 7 5 40

Elongation at break (%) 23 20 14 18 20 3.5

UV rays resistance medium weak medium medium medium good

Specific weight 1.14 1.14 1.38 0.91 0.97 0.97 Resistance to alkalis good good weak good good good

Acid resistance weak weak good good good good

Moisture absorption% (65%-20°C)

3.5-4.5 3.4-4.5 0.2-0.5 0 0 0

(Source: Badinotti, 2011)

UHMWPE is 15 times stronger than steel and up to 40% stronger than Kevlar. UHMWPE netting is 3 times stronger than nylon with the same dimension, and increases the net's strength while the abrasion resistance increases the net's life. Netting can be used for trawl nets, purse seine nets and aquaculture nets. Nylon purse seines last for about 2-3 years while UHMWPE netting ensures 2-3 times more life for the net. The netting twines made with dyneema fibre can be reduced by upto a factor of 2 on thickness (diameter basis) and on weight basis by a factor of 4. This allows fishing vessels to increase their catch potentially by as much as 80% by trawling faster or using larger nets, or to reduce fuel consumption. Besides, less deck space is required due to lower bulk volume of the net. Purse seines made of dyneema would facilitate 40% increase in sinking speed due to better filtering and reduced drag. Larger net for the same weight can be made. The net has better durability with negligible wear & tear.

Ropes made from UHMWPE have a higher breaking strength than that of steel wire ropes of the same thickness, but have only one-tenth the weight. Fishing uses for these high-strength polyethylene ropes include warp lines, bridles and headlines. By using UHMWPE ropes, the frequent oiling & greasing required for wire ropes can be avoided which would facilitate a clean and safe deck and free the crew from greasing the rope frequently. It also helps in a clean catch devoid of oil and grease contamination. Liquid Crystal Polymer Fibre: Vectran®, a high-performance thermoplastic multifilament yarn spun from Vectra® liquid crystal polymer (LCP), is the only commercially available melt-spun LCP Fibre in the world. Vectran fibre is five times stronger than steel and 10 times stronger than aluminum. Vectranfibre is 4 times stronger than polyethylene fibre or nylon fibre. The unique properties that characterize Vectran fibre include: high strength and modulus; high abrasion resistance; minimal moisture absorption; and high impact resistance. Although Vectran is lacking UV resistance, this limitation can be overcome by using polyester as a protective covering. It is very suitable for trawl nets and ropes. Physical properties of Vectran yarn in comparison with the others which has similar diameter are given in Table 2.

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Table 2. Comparative properties of Vectran yarn with other yarns

Properties Vectran UHMWPE Regular

polyethylene Regular

polyamide (nylon6)

Size (denier) 9000 4800 7200 7560 Diameter (mm) 1.31 1.13 1.47 1.26 Weight (g/m) 1.1 0.6 0.89 0.94 Tenacity(wet) *1 (kg) 148 85 35 46 Elongation at break(wet) (%) 9.4 11.2 28.4 41.3 Elongation at break(dry) (%) 9 10.6 32.6 36.7 Resistance for abrasion (wet, 1kg load) *4 (times)

421 295 73 61

Resistance for abrasion (dry, 1kg load) *5 (times)

55 15 - 13

Source: http://www.nagaura.co.jp/english/bect.html Fluorocarbon fibre: Fluorocarbon fibre is a new material that can be used in angling and high-speed jigging lines. It has very high knot strength, almost invisible in water, has high breaking strength and abrasion resistance. Sapphire: Sapphire PE netting manufactured from specialized polymers available in twisted and braided form is suitable for trawl nets and for cage culture. It has the highest knot breaking strength, knot stability and dimensional uniformity. Braided twine having compact construction restricts mud penetration and provides lesser drag. Sapphire is used on a limited scale for fabrication of large mesh gillnets targeting large pelagics in Maharashtra region of India. Sapphire ultracore is a knotless HDPE star netting with an outer layer of heavier sapphire ultracore which features strands of marine grade stainless steel as an integral part of the netting twine. The stiffness and cut resistance enable it to be used as a predator protection net cum cage bag net where the predation problem is very high.

Sapphire Ultracore Kevlar UHMWPE

Among the new fibre types, only Sapphire and UHMWPE are used on a commercial basis

for fishing gear viz., trawls and purse seines in Australia and Alaskan waters. Sapphire is also

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used on a limited scale in large mesh gillnets targeting large pelagics in Maharashtra region of India. Basic yarn types: Fibre is the basic material used for the fabrication of netting yarns. By twisting, braiding or plating, yarns are made into twine. For twine construction, there are two steps, first is the twisting together of two or more single yarns to form a strand/ply and the second step involves the twisting together of two or more strands to form a twine. The basic forms in which most synthetic fibres are produced are continuous filaments (multifilaments), staple fibres, monofilaments and split fibres. Continuous filaments are fibres of indefinite length. A quantity of continuous filaments is gathered up, with or without twist to form a filament yarn termed as multifilament. Staple fibres are discontinuous fibres, prepared by cutting filaments into short lengths usually 40-120 mm suitable for the yarn spinning fibres. Staple fibres are twisted to form a spun yarn. These have a rough surface due to the numerous loose ends of fibres sticking out from the twine. Monofilament is a single yarn strong enough to function alone as a yarn without having to undergo further processing. Unlike fine continuous filaments and staple fibres, this can be directly used as individual fibres for netting. Split fibres, developed from oriented plastic tapes (flat tape) which are stretched during manufacture at a very high draw ratio resulting in the tapes splitting longitudinally when twisted under tension. Probable Yarn types in each polymer group

All fibre types from all the seven chemical groups are not available/suitable as netting yarns. PA is available as multifilaments, staple and monofilaments yarn. PE is available as monofilaments (twisted) but not as staple fibres or as multifilaments while split fibres are not common. In the case of PP, fibres as multifilaments, split fibres and monofilaments for ropes are available. PES is available only as multifilament fibres and not as split fibres.The synthetic netting yarns used in Indian fishing sector are PA, PE and PP. PA and PE are the most commonly used fibres for netting while PP and PE are used for ropes. Of these, PA is mostly used in gillnets, line and purse seine sector while PE is used in the trawl net sector and to a less extent in deep-sea gillnet sector.

Nylon multifilament nettings are available as knotless and knotted while nylon

monofilament nettings are available as knotted only. Nylon multifilament nettings are commonly used for the fabrication of various types of gillnets, ring seine, purse seine, cast net, Chinese nets, drift nets etc. Common specifications of nylon multifilament twine for fishing ranges from 210x1x2 to 210x12x3. The mesh size commonly required ranges from 8 mm to 450 mm for different fishing gear. It is more effective for fishing than polyester because of the better sinking speed and extensibility. Nylon monofilament is better for long lining and various types of gillnetting. The twine range for fishing purpose is from 0.10 to 0.50 mm dia and for long line fishing 1.5 to 3 mm.

HDPE twine is of two types; braided and twisted. Twisted twine is available normally in the range of 0.25 to 3.00 mm dia while braided twine is available in the range of 1.0 to 3.0 mm dia. HDPE netting is mainly used for fabrication of trawl nets.

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Designation of yarn: Monofilament yarn is usually designated by diameter. Multifilament twisted twines are designated by runnage (length of twine against a standard weight) or by designation, viz., the yarn size, number of yarns in the strand, and number of strands in the twine. Example: 200x4x6; indicates that the yarn size is 200 denier, 4 yarns in one strand and 6 such strands are twisted together to form the twine. Yarn numbering system

For designation of the size of the yarn, a `yarn numbering system’ is developed. The size of the yarn is given by yarn numbering system which is based on the length-weight relationship of the yarn. There are two types of yarn numbering systems, viz., direct and indirect.

Direct System: In this system, the weight of the yarn against a standard length is taken. For example the length of yarn is kept constant and the weight changes. i. Denier 9000 m of yarn weighing 1 g is 1 denier 9000 m of yarn weighing 210 g is 210 denier ii. Tex: This is the internationally accepted system of numbering for all textile yarns.

1000 m of yarn weighing 1 g is 1 tex. 1000 m of yarn weighing 20 g is 20 tex

Indirect system: Here the length of yarn for a standard weight gives the yarn number or the weight is kept constant and the length varies.

i. British Count (Ne)

840 yards weighing 1lb is 1 Ne

20x840 yards weighing 1 lb is 20 Ne

This is commonly used for cotton and synthetic staple yarns.

ii. Metric Count (Nm)

1000 m of yarn weighing 1 kg is 1 Nm

20x1000 m of yarn weighing 1 kg is 20 Nm.

In the direct system of numbering the more the yarn number, the thicker the yarn would

be and in the indirect system the more the yarn number, the finer the yarn would be.

For conversion from one system to another, the following conversion formula is used.

Tex= 590.5 = 1000 =100000 = 496055 = 0.11 denier Ne Nm m/kg yds/lb

Identification of synthetic fibres

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Identification of synthetic fibres by appearance alone is not easy and correct. Different physical and chemical test methods are employed to identify groups of synthetic fibres. Specific gravity: Important fibres can be segregated by differences in specific gravities, which are listed below. Air trapped is to be completely removed from the yarn or fibre bundle before determining the specific gravity.

PA :1.14; PE: 0.96; PP: 0.91; PES: 1.38

PE and PP fibres float while other fibres sink in water. Burning test: In the burning test, the nature of burning and smoke in the flame as well as after leaving the flame are considered as detailed in Table 1.

Table 1. Identification of different polymers by burning test

Solubility test: Solubility test is also used to identify different synthetic fibres. PA is soluble in 37% Hydrochloric acid in 30 min at room temperature. PA and PES are soluble in sulphuric acid 97-98% in 30 min at room temperature. PE and PP are soluble in Xylene on boiling for 5 min (Inflammable). Properties Synthetic netting materials generally are resistant to biodeterioration i.e., they are resistant against destruction by mildew in air and bacteria in water. This is the major advantage of synthetics over natural fibres and it is the prime requisite for a fibre for consideration as a fishing gear material. Besides, synthetic fibres have high breaking strength, better uniformity in characteristics, long service life and low maintenance cost. However, unlike natural fibres, they are prone to degradation under sunlight at a much faster rate. As far as the fishing gear purpose is concerned, properties which are of importance are linear density, diameter, specific gravity, knot stability, breaking load, elongation, weathering resistance and abrasion resistance.

Material PA PE PP PES In flame Melts, burns with

light flame, white smoke, melting drops fall down.

Shrinks, curls, melts and burns with light flame, drops of melting fall down.

Shrinks, melts and burns with light flame melting drops fall down.

Melts, burns with light flame, sooty black smoke, melting drops fall down.

After leaving the flame

Stops burning, melting drops can be stretched into fine thread

Continues to burn rapidly hot melting substance cannot be stretched.

Continues to burn slowly hot melting substance can be stretched.

Stops burning, melting bead may be stretched into fine thread

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Diameter: The diameter of netting material is an important factor influencing the fishing gear performance. Thickness and rigidity of the material influences the resistance of fishing gear to water flow and hence the power required or the speed obtained in towing gears are depended on it. Thinner twines offer less resistance. Diameter of a material is dependent on the type of polymer, type of yarn, size of yarn, specification and construction. Diameter is expressed in mm and is measured using a travelling microscope or a micrometer. Linear density; It is the mass per unit length of the material. The mass in g of 1000 m length of a material is expressed as R tex and mass of 9000 m of the material as R denier. While comparing different types of yarns, the Rtex values serve as a relative measure for the mass of netting. For the same kind of material, lower Rtex means thinner material and generally costs less while buying on a mass basis. Specific Gravity: Specific gravity of most of the synthetic fibres is less than the natural fibres. Specific gravity influences the fishing gear as fibres with lesser specific gravity allows a greater length of netting for a given weight of yarn and helps in savings in handling and power. However, for a gear such as purse seine, material with very low specific gravity is not the suitable one as quick sinking of the net is a prime requisite to capture a shoal of fish. Twist: The number of turns or twists imparted to a twine per unit length is important as it influences many properties especially the breaking strength, diameter, linear density, resistance to abrasion and general wear and tear of the twine. As the amount of twist increases the breaking strength also increases upto a critical degree of twist beyond which it would weaken the twine. The stability of a twine depends on the correct amount of twists per unit length. The twine has an inner/strand/primary twist and outer/secondary/twine twist. Balance between these two twists ie: primary twist for making strands from yarns and secondary twist to make twine from strands is important. Twines with a well balanced twist do not have a tendency to snarl. The relation between inner twist and outer twist is:

Inner twist = outer twist x √No. of yarns

The amount of twist decides the softness or hardness of the twine. Based on the amount of twist, the twine is termed as soft, medium, hard and extra hard types. The number of strands in a twine can vary from 2 to 4 but generally 3 strand twines are used for fishing purposes as they possess stability, are free from distortion and round in appearance. The twist can be in two directions, viz., left hand (S twist) or right hand (Z twist). In S twist, the slope of the twisted product follows the direction of the central portion of the letter `S’. Similarly in Z twist, it follows the central portion of `Z’. Generally, the yarns and strands are twisted in the opposite directions for stability. In a double twisted twine, the direction of twist can be SZS or ZSZ for yarn, strand and twine respectively. Twist coefficient is the measure of twist hardness and is determined by the formula

K = (t/m) x (√tex/1000) where ‘K’ is the twist coefficient, t/m is the twist per meter

and ‘tex’ is the count in the direct system of numbering.

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A coefficient of twist of 110-140, 150-160 and 200 denote degrees of soft, medium and

hard twist respectively in PA multifilament netting twine.

Breaking load and elongation: The breaking strength/load of a material denotes the ability of a material to withstand the strain. It depends on the type of polymer, type of yarn, degree of twist and thickness of the material. Tenacity is the breaking load in terms of yarn denier while tensile strength is the force in terms of unit area of cross section. The strength of fibre changes in the wet condition; in natural fibres the wet strength is higher while the reverse is true of synthetic fibres. Knotting also causes reduction in the breaking strength. This is dependent on the type of polymer, type of yarn and knot, twine construction and also on the degree of stretching. Breaking load is expressed in Newton (N). Elongation is the increase in the length of a specimen during a tensile test and is expressed mostly in percentage of the nominal gauge length. Extensibility is the ability of a netting material to change its dimension under a tensile force. It involves a reversible and an irreversible elongation. Irreversible or permanent elongation is the part of the total increase in length which remains after the removal of the stress. Reversible or elastic elongation is the part of the total increase in length which is cancelled again, either immediately or after a long period of removal of stress. Weathering Resistance: Even though all fibres, irrespective of natural or synthetic are prone to degradation on exposure to weathering, the problem is severe with synthetic fibres. The main factor responsible for weathering is the sunlight, i.e. the ultra violet part of the sun’s radiation. Different synthetic fibres show variation in their susceptibility to and rate of deterioration by sunlight depending on the type of polymer and fibre. The rate of deterioration is generally assessed by the loss in breaking strength. The effect of weathering depends on the thickness of yarn as the layers below are protected by the degraded outer layers and generally UV rays do not penetrate more than 1mm. By dyeing the weathering resistance can be improved. PVC has very high resistance against weathering, while PES has high and PA and PE, have medium resistance against weathering. Among different types of fibres, monofilament form is more resistant than multifilament and staple yarn. Abrasion Resistance: The resistance of netting materials to abrasion, ie, abrasion with hard substances such as boat hull, sea bottom and net haulers, or abrasion between yarns/twines is important in determining the life of a net. The resistance to abrasion depends on the type of fibre, thickness and construction of the material. Polyamide has the maximum abrasion resistance, followed by PP, PES and PVC. The better abrasion resistance of PA is due to the inherent toughness, natural pliability, and its ability to undergo a high degree of flexing without breakdown. Among different types of materials, monofilament is better than multifilament, and between staple and multifilament, the latter is better. Abrasion can cause rupture of the material as also reduction of mesh size due to the internal abrasion caused by the friction of the fibres against each other. Choice of material for different gears Even though different types of synthetic fibres are available, an ideal material satisfying all the requirements of different fishing gears does not exist. The various types of synthetics having

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different qualities provide a range of choice for selecting the best suited material for each type of gear. The choice of material depends not only on the technical properties but also on the local availability and price. For each type of gear, a particular property of the material may be important; for example, sinking speed for purse seine, transparency and softness for gillnets, high breaking strength and abrasion resistance for bottom trawls etc.

Fishing gears are classified into three main groups based on the strain the net material has to undergo. The classes are: Group 1-Low strain (Fine gillnets); Group 2-Medium strain (Fishing line, traps, scoop nets, dragged nets including small bottom trawls); and Group 3- High strain (Large bottom trawls, gape nets in fast flowing rivers). The material indicated as suitable for each group by Japan Chemical Fibre Association is given in Table 3.

Table 3. Synthetic fibres suitable for different fishing gears Material Groups Fishing Gear

PA Group 1,2 Gillnets, purse seines (sardine) PE Group 2,3 Trawls PP Group 1 Entangling nets PVC Group 2 Set nets, Lift nets PVA Group 2 Purse seines (Tuna, horse mackerel)

Gillnets: For maximum catching efficiency, the material should be fine, strong, flexible and be invisible in water. The material should be thin and soft but be sufficiently strong to withstand the struggle of the fish to escape. The firmness of fish body and extensibility of the material are also to be considered while choosing the material. The efficiency of gillnets depends on the visibility of nets. These conditions are fulfilled by synthetic fibres especially nylon monofilament yarn. The ratio of diameter of twine to mesh bar is an important criterion to be considered while designing gillnets. Thicker twines are more visible and are easily detectable by the lateral line sense organs of the fish. However, too thin material especially, nylon monofilament, would cut deeply into the body of the fishes and while removing the fishes from the net, the fish gets damaged with cuts and bruises on the body and loss of scales. This results in quality loss and price loss. Trawl nets: Material should be strong, having good abrasion resistance and cheap to buy. HDPE is the material used in India for trawl nets. In trawl nets, >50% of the drag is contributed by the netting. Hence, use of finer and lighter twines in trawl nets reduce the drag substantially. Purse seines: Netting material for purse seine should have high specific gravity to increase the sinking speed during setting.The material also should be having sufficient strength for pursing and hauling when huge shoal of fish is caught. Twisted knotless netting and Raschel braided netting are lighter and are widely used for purse seines. But, of late knotted webbing is preferred over knotless webbing, because of the difficulty to repair knotless webbing when damaged. Being a huge net, the material used for purse seine should be thinner (preferably knotless) to reduce the bulkiness of the net. High breaking strength, excellent elastic properties, high specific gravity, low resistance against current, and good water shedding capacity are important properties to be considered while selecting material for purse seines.Mostly, the bunt and selvedge portions are

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constructed using knotted net for the required strength in these parts of the net. Among synthetic materials polyester and nylon are preferred as they are having high breaking strength. In India, nylon is exclusively used for purse seines and ring seines. Energy conservation

The modern mechanized fishing operations are highly energy intensive and exploit the limited reserve of the non-renewable fossil fuel. The mechanized and motorized fishing fleet of India has been estimated to consume about 1220 million litres of fuel annually (Boopendranath, 2006). Design of fishing gear and operating conditions influence the drag of fishing gear components. Among different components of gear, netting forms the main component and the hydrodynamic characteristics of netting substantially determine the drag especially in active fishing gears. More than 50% of the total drag of trawl gear is contributed by netting.

For a netting panel, drag depends on the netting area, flow velocity, solidity ratio (ratio of twine diameter to bar length), weaving pattern (braided or twined) and attack angle (angle between the current direction and normal to a net plane). Drag is also affected by knot type, twine material and netting-surface roughness. Knotted netting is more drag resistant than knotless netting. Evaluation of hydrodynamic characteristics of netting panels made of PE netting, PES netting by flume tank experiments by Tang et al. (2019) revealed that the drag generated by knot accounted for 21% of the total drag of PA netting and for braided knotless netting, the drag coefficient of PA netting was about 8.4% lower than that of PE netting and 7% lower than that of PES netting. Compared with twined netting, the braided netting showed a higher resistance to flow (Tang et al., 2019). Therefore, selection of type of material and netting construction are important for energy conservation. Material-based interventions that can largely help in energy saving in fishing are use of (i) knotless netting and (ii) thinner twines with high strength.

The UHMWPE material is an ultimate solution as a material with thin diameter but high

strength. The low diameter of these twines and their favourable weight/strength ratio produce up to 40% less drag than conventional fibre structures as the net is pulled through the water or set against tide/currents. Dyneema trawl nets result a fuel saving upto 40%. Due to the lightweight property with minimum drag in the water, the material helps fishers to reduce fuel costs by 40%. New Zealand fishermen reported an average savings of one tonne of fuel per day while using twin-rig trawls made with UHMWPE sold under the trade name Dyneema® (Anon, 2009a). The trawls incorporating Dyneema products showed excellent geometric characteristics and a considerably reduced hydrodynamic drag (Sendlak, 2001). UHMWPE ropes can be used in trawling to substitute wire ropes which helps in weight reduction and drag reduction resulting in fuel saving. In purse seines, the use of UHMWPE facilitates faster sinking due to better filtering and reduced drag. Faster sinking also reduces the chances of escape of the fish shoals encircled. UHMWPE has made its impact in the fishing and culture sectors elsewhere in the world, its technical and economic feasibility in the Indian context need to be investigated and standardized. Though the material is claimed to have many advantages, the very high cost involved is a major disadvantage. The ICAR-Central Institute of Fisheries Technology has taken up the initiative of testing the performance of UHMWPE netting and ropes in the Indian context in collaboration with DSM, India and Garware Wall Ropes Ltd Pune. The study indicated that UHMWPE trawls are technically feasible as low drag trawls with 17% less drag than conventional HDPE trawls and

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saves 10% of fuel (Sayana et al., 2018). The fuel consumption per kilogram of fish captured was also estimated to be 2.9 liters for HDPE trawls and 1.9 liters for UHMWPE trawls with an average (Sayana et al., 2018). UHMWPE rope field tested by CIFT on Dept vessel showed better durability with no greasing or other maintenance. Economic feasibility of the material is under evaluation. Resource conservation

Bycatch including juveniles, ghost fishing, plastic pollution etc influence the sustainability of resources. Choice of right material and its responsible use can reduce adverse effects on resources and the ecosystem.

Bycatch

Bycatch can be minimized by use of materials which do not absorb water and shrink thereby reduce the mesh size. Nylon netting lose about 10-20% of its dry knot strength on immersion in water while UHMWPE netting do not absorb water. As there is no shrinkage due to wetting, the mesh size and shape are maintained during fishing. Hence, trawls made with UHMWPE fibres especially in the cod end maintain their shape and facilitate better filtering thereby reducing bycatch and juvenile catch. With low elongation, as little as <5%, and no shrinkage in water, the mesh size remains stable during normal use of UHMWPE netting allowing better filtration and reduced bycatch.

Ghost fishing

Ghost fishing is an issue directly dependent on the choice of material. Abandoned, lost or otherwise discarded gear (ALDFG) has always been happening during fishing. But it became an environmental issue since the use of non-biodegradable synthetic fibres. Once gear is lost, it drifts along with the current and waves and as long as the gear configuration is intact, ghost fishing continues. Use of natural fibres such as cotton or jute to rig the floats on the gear ensures disintegration of the float rope within a short period of time. Once, the floats are lost, the gear loses its configuration and sinks to the bottom, preventing further ghost fishing.

One of the reasons for ALDFG to occur is the use of very low-quality material. In India, though BIS standards are laid for minimum requirements to be fulfilled by different netting materials for specific gears, multitudes of low-quality materials are available in the market. Use of low-quality material gives chances of more material to be lost in sea and other waterbodies when entangling with obstructions or in rough weather.

Fishing induced plastic pollution: Since modern fishing gear is made of synthetic fibres coming

under the general term, `plastics’, lost fishing gear/ALDFG adds to the marine/plastic debris. Plastics break down into microplastics (<5 mm in size) which further degrade into nano-sizes at an extremely low degradation rate taking several hundreds of years. Microplastics in seawater and marine sediments are rapidly increasing, and are entering into the food chain becoming a long-term threat to the mankind. It is estimated that ALDFG contributes 10% of the marine debris and hence, fishing gear must be operated cautiously to avoid gear loss either accidentally or deliberately.

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Biodegradable netting: Use of biodegradable float line, prevents ghost fishing, but the gear sunk on the sea bottom adds to plastic debris and entangle with coral and other bottom biota. Bioplastic materials which are biodegradable are more beneficial to prevent ghost fishing. In the last couple of decades, more attention has been given to bioplastics and its application in fishing industry. Plastics derived from renewable sources such as polysaccharides: cellulose, starch, chitin and others or from protein sources such as silk, collagen, soy, casein which are abundant in nature are collectively termed as bioplastics. Synthetic bio-based fibres are produced by modification of natural polymers, synthesizing by microbial systems and synthesizing polymers from bio-based monomers. All biobased plastics are not biodegradable as biodegradability of the plastics depends on the chemical structure and not on the source. Petroleum-based polymers such as PBAT (polybutyrate adipate terephthalate) and PCL (polycaprolactone) are biodegradable.

Polylactic acid or polylactide (PLA) is one of the most widely used bioplastics. PLA (is based on lactic acid, a natural acid, which is mainly produced by fermentation of sugar or starch with the help of microorganisms. Blending PLA with other polymers improves its mechanical properties.

In the fishing industry, environment friendly fishing line made of biodegradable polymer made from poly butylene succinate (PBS) is a recent development.`Bioline’is a commercial fibre made from PBS which retains its strength and durability for few months of use and then completely degrades in water (salt or fresh water) through the enzymatic reactions of naturally occurring microorganisms in the water. It does not deteriorate when kept clean and dry, but when exposed to bacterial activity underwater or underground, it deteriorates viz., it retains its strength and durability for the first 10-12 months of use and then completely degrade in water or on land within five years. FIELDMATE™ is another example for biodegradable polymer. If exposed for three months in salt or fresh water, it decomposes through the enzymatic reactions of naturally occurring microorganisms, before eventually being reduced to water and carbon dioxide.

Conclusion

Plastic materials due to very good strength, durability and other vital properties, are extensively used in fisheries. The introduction of synthetic fibres has revolutionized the fishing industry and it can be considered as the major single factor which led to the development of today’s efficient fishing gears. However, the responsible use and disposal of materials are very essential for resource conservation, energy saving and ecological well-being.

References/suggested reading Anon (2009a) Trawlers switch to Dyneema® D-

Netting, http://www.worldfishing.net /features101/product-library/fish-catching/ trawling/trawlers-switch-to-dyneema-d-netting (Accessed 10 August 2012)Bandinotti (2011) Net with Dyneema® http://www.badinotti.com/aquaculture% 20dyneema%20netting.html (Accessed 28 July 2012)

Boopendranath, M. R. (2006) Energy conservation in fishing operations. Fish Technol. Newsletter, 17 (3):2-4

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Sayana K.A., Remesan M.P. and Leela Edwin (2018) Low drag trawls for fuel saving. FishTech Rep. 4 (1): 1-3

Sendlak, H., Nowakowski, P. and Winiarski, J. (2001) Fisheries: Analysis of geometric and drag related characteristics of pelagic trawls with components made of dyneema polyethylene fibres. Electronic J. Polish Agri. Universities 4(2) #01. http:// www.ejpau.media.pl/volume4/ issue2/fisheries/art01.html

Tang H, Hu F, Xu L, Dong S, Zhou C, Wang X. (2019) Variations in hydrodynamic characteristics of netting panels with various twine materials, knot types, and weave patterns at small attack angles. Sci Rep. 9(1):1923. doi: 10.1038/s41598-018-35907-1

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Classification of Fishery Vessel types M.V.Baiju

Senior Scientist, ICAR-Central Institute of Fisheries Technology, Kochi


Based on the type of fishing employed, the FAO has classified fishing vessels into many

categories. Trawlers

The fishing gear used by these vessels are trawls as and are provided with powerful engines tow the net and vessel at the appropriate trawling speed. They are fitted with trawl winches and mast and boom arrangement to haul the net on board and lift the cod-end over the deck. Depending on the area of operation and the trawl used, trawlers range in size from open boats with inboard motors up to large freezer and factory trawlers.

Bottom as well as midwater trawls can be used with only minor modifications of fishing equipment. Pair (two-boat) trawling achieves the spread of the net by towing the warps between two trawlers of the same or reasonably similar traction power. Lay-out of a typical pair trawler is often similar to that of a side trawler, the larger vessels frequently having a net drum to handle the pair trawl which are larger than those of single (one-boat) trawlers of similar size.

Side trawlers

Side trawlers set the trawl net over the side and the warps pass through blocks hanging from two gallows, one forward and one aft. Usually the superstructure and the wheelhouse are placed aft, the fish hold is situated amidships and the trawl winch transversally at the front of the superstructure as shown in the figure below. Around the gallows the hull is strengthened against chafing of the otterboards. When the vessel is not trawling the otterboards are stowed between the gallows and the bulwark.

Fig.1.1 Side trawler

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Stern trawlers

The stern trawlers lead the warps from the trawl winch through various lead blocks to the after deck and over the stern. The wheel house or bridge is usually situated in the forward part of the vessel. Medium sized and large stern trawlers are often fitted with a stern ramp, on which the trawl is hauled on to the deck. On small vessels a stern roller is used to reduce friction when shooting and hauling up the trawl. The trawl winch is placed transversely usually behind the wheel house. On small vessels the fish hold is situated amidships and on medium sized and large stern trawlers in the forward part of the vessel.

Fig 1.2. Stern trawler Freezer trawlers

In these vessels the fish is preserved by freezing. Freezer trawlers are outfitted with refrigerating plant and freezing equipment. The holds are insulated and refrigerated.

Fig 1.3. Freezer trawler

Factory trawlers

Factory trawler are generally large stern trawlers equipped with processing plants including mechanised gutting and filtering equipment with accompanying freezing installation, fish oil, fish meal and sometimes canning plants. Separate holds are provided for each of the products. Extensive superstructures are typical feature of factory trawlers.

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Fig.1.4 Factory trawler

Outrigger trawlers

These vessels have strong outrigger booms to tow the fishing gear. The outriggers are usually fastened to the mast and extend out from the sides of the vessel each towing one or two trawls. These are used for shrimp trawling. Another method using outrigger, is the use of very heavy outrigger and gear for towing trawls fitted with beams and heavy bottom gear which is principally used for the capture of flat fish.

Fig.1.5. Outrigger trawler

Seiners

Seiners use surrounding and seine nets. They comprise a large group ranging from open boats and canoes up to large ocean going vessels. They are used to catch predominantly pelagic species. Relatively high manoeuvrability is required for operation of the surrounding and seine nets. Large seiners are therefore often fitted with lateral thrusters. To assist in fish school spotting observation crows nests are fitted on masts. The equipment of seiners consists usually of a power block and a net drum for hauling and stowing the net aboard and one or more winches

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for setting and hauling operations. Small boat and canoe type seine neting, all operations are generally performed by hand. For removing of fish collected in the purse, a brailer attached to a derrick is provided. Species of small size are often removed by pumping arrangement. In that case a pump is lowered from the derrick into the pursed seine and the fish is pumped through a hose and a water separator on deck into the hold.

Purse seiners

Vessels using purse seines are equipped with pursing gallows and pursing winches for hauling the purse lines which close the net after setting, see Figure 7. From the viewpoint of deck arrangement two main types of one boat purse seiners can be distinguished: the North American type, and the European type.

North American type purse seiners

These seiners have the bridge and accommodation placed forward. The power block is slung from a derrick attached to the mast behind the wheelhouse. The winch is usually fitted with parallel drums and is situated opposite the pursing gallow. The net is carried at the stern of the vessel.

Fig.2.1.1 Purse seiner

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Fig.2.1.1.A.Purse seiner

European type purse seiner

This type of purse seiner has the bridge and accommodation located aft. The fish hold is situated amidships. The net is mostly carried on the upper deck and the power block is fitted to the side of the bridge with separate transport blocks or rollers to stow the net on the aft deck as in Figure 2.1.2. The purse winch is situated forward with the drums facing the pursing davit.

Fig.2.1.2. European purse seiner Tuna purse seiners

These vessels are large purse seiner with the same general arrangement as the North American type, equipped to handle very large and heavy purse seines for tuna. They are normally equipped with a skiff located on top of the net at the sloped part of the stern of the vessel. Their

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deck equipment consists of a three drum purse-seine winch and a power block, with topping, vang, cork and other specific winches to handle the heavy boom and net. A crows nest is placed at the top of the mast. The search for tuna schools is often carried out by a helicopter, for which a landing platform is provided.

Fig.2.1.3.Tuna purse seiner

Seine Netters

For this fishing method, fishing area is surrounded by a net attached to very long ropes. Next the net is towed or dragged over the bottom. It is not to be confused with purse seining which is an encircling net used for catching schooling fish. The nets used in this type of fishery are similar to light high opening bottom trawls but they use long lengths of seine rope spread out on the sea bed on each side of the net as shown in Figure 2.2. Anchor seining (dragging), often known as anish seining due to its country of origin, uses an anchor which is buoyed and to which the first rope is attached. - 15 - The vessel lays out the ropes and net returning to pick up the anchor line to which the vessel lies during the hauling process. The second variation, fly dragging or Scottish seining, does not use an anchor, instead a combination of winch and propeller is used to simultaneously pull and close the gear. The vessels using this gear resemble side trawlers as almost all have the wheelhouse and accommodation aft. The main problem in deck layout is stowing the ropes. They may be laid .in coils on the side deck, or in bins extending from the deck to the fish hold floor· The best modern way of handling them is to put them on hydraulic reels fitted on deck. The winch itself is a small but fast and powerful two-barrel type to which a coiler maybe attached if the ropes are coiled on deck or in bins. A power block is fitted aft and the net is hauled in there. The cod-end is lifted aboard on the side deck. A variation of the method is used by modern Japanese seiners in which the gear handling area is located aft and the wheelhouse forward.

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Fig.2.2.Seine netter Dredgers

Dredge fishing vessels use a dredge for collecting molluscs from the bottom. The vessel drags the gear and the power requirements can therefore be similar to those of a small trawler. A powerful water pump is necessary to operate the waterjets of a mechanical dredge. For lowering and lifting of the dredge, derricks and winches are installed. Small boat dredges are operated from boats and other small vessels. Some small inshore dredgers operating in shallow waters can also push a gear fixed to a beam extended from the bow.

Fig.3. Dredger

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Lift Netters

These vessels are equipped for the operation of large lift nets which are held out from the ship's side and raised and lowered by means of outriggers as seen in Figure 4. Sets of powerful lights for fish at tract ion are mounted as shown, and of ten used simultaneously with underwater lights. The vessels have the bridge amidships and are fitted with derricks and winches for handling the lifting lines, outriggers and light booms.

Fig.4.Lift Netter

Gill Netters

Boats and canoes use gill net in inland waters. The decked small gill netters fish in coastal waters and medium sized vessels operate gillnets in offshore. Small gillnetters have their wheelhouse either aft or forward. On medium sized vessels, using drifting gillnets and called drifters, the bridge is usually located aft. For drifters it is essential that they lay to windwards when drifting with the net. They are therefore often fitted with a steadying sail. On small vessels setting and hauling operations are performed by hand. Larger vessels are often equipped with hydraulic net haulers or net drums

Fig. 5. Gill netter

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Pot Vessels

These vessels are used for setting pots for catching lobsters, crabs, crayfish and other similar species. Pot vessels range from open boats operating inshore up to larger decked vessels of 20-50 m operating to the edge of a continental shelf. On open and partly open boats the wheelhouse is placed forward. In the cockpit a suitable place to store pots is provided. A live well with sea water for transport of the catch is also situated on' the cockpit. On small decked pot vessels the wheelhouse is located either forward or aft and the fish hold amidships. Larger pot vessels are equipped with derricks, cranes or davits for setting and hauling of pots. On smaller vessels mechanized pot haulers are fitted.

Fig. 6. Pot vessel

Liners

These vessels use lines and hooks with or without bait or lure. Depending on the method of fishing with lines, area of operation and species to be caught, liners comprise vessels of all size classes. Containers or tanks for storing the bait, sufficient deck area for attaching the bait to the hooks and a convenient place for preparing the lines for setting and hauling are typical features for line fishing vessels.

Hand liners

Hand lines are operated from boats, canoes and other small vessels, without any special features for gear handling. Hand lines can be set and hauled either manually or by mechanised reel. If mechanized reels are used, these are fastened to the gunwale.

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Fig.7.1.Hand liner Long liners

Long lines can be operated from vessels of any size adapted for the length of long line to be set. Bottom long lines are placed on or near the bottom and drifting long lines are maintained at the surface or at a certain depth by means of floats. In typical arrangements the gear is hauled from the bow or from the side with a mechanical or hydraulic line hauler and the lines are set over the stern. The wheelhouse can be situated aft or forward~ but on larger vessels the bridge is generally placed aft. Several automatic or semi-automatic systems are used on bigger boats to bait the hooks and to shoot and haul the lines.

Fig.7.2.Long liner

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Fig.7.3.Long lining

Pole and line vessels On these vessels, used primarily for catching of tuna and skipjack, the fishermen stand on the railing or on special platforms and fish with poles, to which a line with hook is attached. Tanks with live bait and a water spray syste~ for fish attraction are typical features of these vessels. Because live bait is used to attract fish, the fishing method is also known as live-bait fishing. Two types of pole and line vessels can be distinguished: the Japanese type, the American type.

Fig.7.4. Pole and liners

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Fig.7.4.1 Pole and liner in Lakshadweep, India Trollers

Equipped for catching pelagic fish swimming close to the surface these vessels tow a

number of lines fitted with lures. The lines are attached to trolling booms which are raised and lowered by topping lifts and fore and aft stays. Hydraulic or electrically powered reels (gurdies) are frequently used to haul in the lines as shown in Figure 7.5. According to area of operation, vessels may be laid out with wheelhouse and mast either forward or in the after part of the vessel.

Fig.7.5. Troller Vessel using pump for fishing

These vessels are provided with pumps of special construction. During the fishing operations the pump is lowered under the surface of the water. The pump is suspended on the hook of a derrick and is operated from the vessel's electrical plant. Small fishes attracted by light

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from a lamp situated above the suction side of the pump are sucked and pumped with water on board, where a fish water separator is installed.

Fig. 8. Pump onboard fishing vessel Multipurpose vessels

These are vessels which are equipped for alternative use of two or more different fishing gear without major modifications to the vessels' outfit and equipment. The simplest examples of this concept are traditional open craft which operate one of the surrounding net types of gear, e.g., purse seine, during the seasonal appearance of pelagic species and handlines for demersal fish during the remainder of the year - no special features or equipment are used and the appearance of the craft is unchanged. Other examples of combinations in common use are gillnetter/longliner, trawler/gillnetter, trawler/purse seiner etc., with a variety of other gear being used in cases where gear and equipment investment is not high and layout changes minimal, e.g., a gillnetter may use handlining, trolling and trap fishing when seasonal variations are appropriate. Non-fishing vessels Motherships These vessels provide fishing vessels at sea with supplies of fuel, provisions, fresh water and other consumable goods, transfer the catch from the vessels, process and preserve the fish, render medical and social services to the crews. They also transport and land fish products in port. In this category the following two types of motherships can be distinguished: salted fish motherships, factory motherships. The term "mothership" is also used for vessels which carry on board small fishing vessels; on arrival ,at the fishing grounds the fishing vessels are launched and perform the fishing operations. The catch is transferred to the mothership for processing and preserving. At the end of the fishing period the fishing vessels are hauled aboard and the mothership returns to the port. This category is represented by the following two types of motherships: motherships with tuna long liners aboard, motherships for two-boat purse seining.

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Salted fish mother ships

These vessels cooperate with trawlers or drifters in unloading wet fish on the mothership where the fish is salted, cured and put into barrels which are then stored in dry or refrigerated holds, depending upon the degree of salting. The general arrangement of these vessels is that of the three island type. The accommodation and bridge are concentrated amidships and the holds are situated forward and aft. For the loading operation masts, derricks and winches are installed. The vessel has sufficient tank capacity and provision rooms to provide the fishing vessels with fuel, fresh water and provisions. Bathrooms, medical services, library and cinema are provided for the use of crews from the fishing vessels during the loading operations.

Factory mother ships In this category of mothership fresh fish transferred at sea from fishing vessels undergoes processing and preserving operations similar to those which are provided on factory trawlers. The engine room and the main part of the crew quarters are located aft. The bridge and the remaining part of the accommodation on larger vessels could be situated forward, In the middle part of the vessel the processing and freezing lines are installed on the tween decks and refrigerated holds are placed under the main deck. Facilities for recreation and medical services are also provided on board.

Fig.10.2. Factory mother ship

Fishery research vessel

Research vessels are mainly engaged experimental fishing using various gear experiments. The size of fishery research operation and on research programmes. The vessels are usually fitted for the operation of two or more fishing gear. Special winches for taking samples and apparatus for measurements of environmental characteristics are provided. The

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accommodation comprises space for laboratories and quarters for scientific staff. Store rooms for instruments and samples are also provided.

Fig.11.Fishery research vessel

Fishery training vessels

These vessels are used for training future fishermen and students in navigation, seamanship, fishing operations and fish handling. They are mostly typical fishing vessels with additional accommodation for trainees. References/ Suggested reading Ref: Definition and classification of fishery vessel types, FAO fisheries technical paper, No.267-1985

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Boat Building Materials with Special Reference to Environmental Impacts

N. Manju Lekshmi* and Leela Edwin

ICAR-Central Institute of Fisheries Technology, Kochi *E-mail: [email protected]

According to FAO (2004), world fishing fleet consists of 4 million vessels in which 2.7 million

were open boats and remaining were traditional crafts. Most of the decked boats were mechanized but only one third of the undecked fishing boats were motorized while traditional crafts were operated by sail and oars. From the time immemorial, fishing vessels has played a pivotal role in maritime operations. They fulfill the demand of fisheries sector to a great extent. The common materials used for the boat construction in India include wood, glass/fibre reinforced plastic, aluminium, steel, plywood, ferrocement etc. While selecting a material for boat construction some basic factors to be considered are type, size, speed, shape of the vessel, availability and suitability of the material and economic and environmental viability. The performance and efficiency of a boat is directly dependent on the choice of the boat building material which also has a direct impact on the environment. By taking these facts into account, a boat designer can select the best possible alternative for building a boat of high efficiency and durability. At present the larger class of vessels are made of steel while vessels belonging to medium and lower category mostly use wood for construction. Fiberglass, ferrocement and aluminium are the new substitutes for conventional boat building material as these can improve the lifespan of the crafts. However, traditional crafts still play a vital role in this era. This chapter gives a brief idea on the common boat building materials and their impacts on the environment. Wood

From ancient times, the use of wood and the value of the forest were improved significantly as the population of humans and their economies grew. Wood has been used for various marine constructional purposes due to its excellent properties like buoyancy, workability, strength, elasticity, durability, heaviness (480-624 kg m-3 at 12% moisture content), load-bearing capacity, treatability, nail holding power, strength to weight ratio and poor transmission of heat. Reusable and recyclable natures are some of the added properties of wood which might have attracted the boat builders for its application in the boat building sector. Normally before boat construction, wood is air seasoned and the moisture is reduced below 15% making it suitable for the purpose. Many of the motorized and non-motorized crafts in India are made with wood. According to FAO (2015), India has 70.7 million hectares of forest land and around 2000 timber species in which about 59 species of timber are used in the construction of fishing crafts in India. Timber species which are in good demand for boat building includes Artocarpus hirsutus (Aini), Calophyllum inophyllum (Punna), Hopea parviflora (Iron wood), Stroemia lanceolata (Venthekku), Mangifera indica (Mango), Melia composita (Malabar neem), Pterocarpus dalbergioides (Paduak), Pterocarpus marsupium (Venga), Shorea robusta (Sal), Xylia xylocarpa (Irul), etc. (Santhakumaran and Jain, 1986).

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Even though wood is a favoured material for the boat building sector, the hygroscopic nature makes it susceptible to bio-deterioration. The biotic and abiotic agents cause deterioration and eventually reduce the life span of the wooden crafts.

The use of preservatives protects the wood from the attack of fungal decay, harmful

insects and marine borers by applying selected chemicals as wood preservatives. Proper seasoning and preservative treatment extend the service life of timber by 3 to 5 times and also it helps in proper utilization of timber and conservation of forests. Hence, the durability or the life of wooden crafts can be increased by the application of preservatives. The degree of protection obtained depends on the kind of preservative used and achieving proper penetration and retention of chemicals. In ancient times, traditional fishermen used sardine oil, cashew nut shell liquid, neem oil etc. as natural preservatives for increasing the life span of wooden boats. Even though the traditional preservatives are of natural origin, they are not much efficient due to its less penetration and retention into the wood. Short term retention of traditional preservatives necessitates the frequent maintenance procedure and consequently increased the operational cost. This leads to the introduction of chemical preservatives such as chromated copper arsenate (CCA), copper chrome boron (CCB), acid copper chromate (ACC) etc. in the boat building sector.

The main objective of wood preservation is to introduce the preservative into the wood so

that a deep continuous layer of treated wood contains sufficient preservative to prevent decay and insect attack (FAO, 1986), and thereby enhances the quality and shelf life of the wood. Preservatives should possess two criteria that they must provide the desired wood protection in the intended end-use and also it should be environment-friendly. Presence of arsenic and chromium in many preservatives was of great concern to the environmentalists due to the bioaccumulation in the aquatic environment. One of the important areas of research was finding an alternative and eco-friendly substitute for synthetic preservatives like CCA. As a result, novel preservative like CCB becomes popular. Nowadays, studies are going on to incorporate nano compounds to the preservatives to increase the efficiency of preservatives and to reduce the environmental impacts.

In backwaters and reservoirs of India, basket boats/coracles made of bamboo are used

since long. It is made by bamboo splits weaved to form basket of good strength. The cost of construction of bamboo boat/coracles are comparatively lower than other material of the same capacity. Bamboo preservation can be done in green and dry condition. Freshly cut culms are immersed in concentrated water-borne preservatives (5-10%) for one to two weeks. Dry bamboo can be treated with oil type solvent preservatives. Plywood

Marine plywood is extensively used for marine vessels construction due to its commercial feasibility, high economical viability and relatively low damage in aquatic conditions. Marine plywood is prepared by gluing together a number of thin veneers of wood using a waterproof adhesive such as epoxy or phenol resorcinol. The wooden plywoods are bonded under high temperature and pressure with phenolic resin glue. Best quality marine grade plywood should have atleast 5 layers of veneers. The marine plywood is having strength-to-weight ratio. The adjacent veneers are kept in such a way that the grain direction is in right angles to each other.

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The most common preservative for plywood used in boat construction is chromated copper arsenic (CCA). After the preservative treatment, the panels are re-dried to a moisture content of 18%. The kiln drying method is preferred so as to minimize the development of bends and cracks. Many uses of plywood in boats involve laminating fiberglass over a plywood boat component. The fiber glass coating protects the underlying plywood from abrasion and wear during landing and launching of boats. Marine plywood boats can ensure protection in severe conditions if it is made of durable or treated veneers. Fibre reinforced plastics/FRP

Fibre reinforced plastics or FRP is also known as Glass reinforced plastic/GRP. The usage

of FRP as a boat building material is flourished because of its low production cost and anticorrosive property. It is also easy and simple to fabricate. The main material components of FRP are the reinforcing agents like glass fibre in the form of thin fibre and a plastic resin capable of impregnating fibres. For the construction of FRP boat, the primary requirement is a mould.

The most popular reinforcement used is a form of glass processed into filaments which

are then chopped and supplied in rolls. The thickness depends on the weight of the glass in grams per square meter. The two main types of glass fibres available in the market are “chopped strand mat” and “woven roving”. The chopped strand mat (CSM) is made up of long fibre glass strands that are randomly oriented and held together with a binder glue. These are available in fabric form as rolls or in small folded packages with varying thickness. This material is specified by weight in which 300, 450, 600 and 900 g/m2 are popular weights of CSM. The boat builder purchases it in rolls of 30–35 kg which are about 1 m in width. Woven roving (WR) is made from continuous glass fibre roving to increase strength and stiffness of the laminate which is sandwiched between layers of fibre glass mat. The greater strength of laminate can be achieved by using such woven glass mats. Resin is the unsaturated polyester. Polyester resin is the main type used in the boatbuilding industry worldwide. It has good compressive strength properties but has low rigidity, tensile strength and impact strength which necessitates reinforcement with fibre glass. “Unsaturated” polyester resin is the more appropriate term for the liquid state in which it is supplied. When cured to the solid-state during the laminating process it becomes “saturated”. Terylene is another example of saturated polyester resin and is a plastic and non-organic material. There are two main types of resins - “laminating” and “gelcoat”. The former is a translucent liquid of various pale colours. The latter is a more viscous liquid both with a strong smell of styrene which is a characteristic of resin. The difference is in the use where the gel coat is applied directly to the mould without reinforcement and provides a smooth, coloured finish to the outside of the hull while the laminating resin provides the matrix within which the reinforcement is bedded. Properties to be considered for boat building lay-up resin are resistance to water absorption, resistance to ultra-violet radiation and weathering, reaction to and from other liquids and solids adhesive qualities and its strength.

A catalyst changes the monomeric unsaturated polyester resin to a polymeric saturated

resin that is, to a harder state, by the production of an exothermic reaction and will cure the resin. The resin is activated by a catalyst. The accelerator governs the speed of the reaction and without the catalyst, the accelerator does not affect on resin. Accelerator normally comes as two chemicals a purple liquid (Cobalt Naphthenate) is usually offered for use with Methyl Ethyl Ketone Peroxide

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(MEKP). Accelerator and catalyst must never be mixed directly together as they can cause an explosion. The flashpoint for both can be as low as 20°C.

Twenty years is often quoted as the lifespan of an FRP vessel. However, there are many vessels

older than this still very sound and in service. It is also obvious that a FRP pleasure boat which is well maintained and rarely used will have a longer service life than an FRP trawler in daily use and repaired only when something breaks. The fact is that an FRP trawler is more likely to become worn out through rough handling, lack of maintenance and breakages than any sudden structural failure of the hull laminate after a fixed period. Aluminium

Aluminium is selected as a boat building material due to its lightweight with high strength, durability and easiness to repair. Since it is lightweight, it has more carrying capacity and greater speed. The elasticity of modulus is 6960 kg/mm2 with high impact resistance. Aluminium is a corrosion-resistant material due to the production of a surface film of aluminium oxide. This oxide film thickens with time and when scratched a new protective film is built up. Pure Al containing 99.5% or more and minimal amount of silicon and iron has the highest corrosion resistance of all Al alloys. As this is too soft for application aluminum is alloyed with Mg, Mn, and silicon for marine application. The higher the Mg content in marine Al, higher the strength and the upper limit of Mg content is 5.5 % both from a corrosion point of view and from the workability point of view. Aluminium boats cost more for the fabrication but painting is not essential for these boats except antifouling paints. Antifouling paints should be carefully selected and it should not contain mercury because it destroys aluminium by forming an amalgam. Aluminium pieces are joined by the welding process where heating during the process partially reduces the strength and hence care should be taken. Attention must be given during the installation of electric circuits to avoid currents. The scrap value of aluminium is more.

The ultimate tensile strength of marine Al ranges from 31,000 - 48,000 psi. the elastic

modulus for Al is about 1/3 that of steel. Al has greater impact resistance than steel. Al is non-sparking and non-magnetic. The co-efficient of thermal expansion of Al is about twice that of steel. Al has high heat reflectivity- 90 % as compared to 50 % for steel thus Al will emit only 10 % of the heat from the sun while steel emits 50 %. Insulation and refrigeration requirements are smaller in fish holds. Al is much more hygienic than steel Al has more thermal conductivity, 3 to 5 times more than steel depending on materials in consideration and therefore uniform distribution of temperature takes place faster in aluminium fish holds.

The use of aluminium for fishing craft construction offers a number of advantages that

includes improved stability, reduced displacement and therefore improved maneuverability and increased cargo carrying capacity, increased speed and increasing operating range, decreased engine size, decreased fuel consumption, reduced maintenance therefore less idle time. Ferrocement

Ferrocement is a combination of wire mesh impregnated within mortar of fine sand and cement. The main difference between ferro-cement and other forms of reinforced concrete is in the use of a fine-grained aggregate and fine meshed reinforcement in a thin shell structure. The

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fine ingredients give increased flexural and shear strength, increased specific surface, improved tensile bonding capacity, crack inhibition due to high proportion of small diameter wires in mesh and resistance to corrosion due to restriction of crack widths below critical values above which moisture could enter the shell structure. The strength of ferrocement is related to the weight and distribution of the steel reinforcement. Cement used are of two types- Type II Portland and V rapid hardening containing not more than 10% tricalcium aluminate. Sand having quartzite with grain size more than 2 mm is used. Additives are used to keep the water content low. Lignosulphates are used as additives. The advantages of ferrocement are high flexural strength, resistance to corrosion, high surface area and it can be built without any skilled labour. Raw materials are easily available and cost of construction is less than timber and steel.

Steel content is the weight of steel per unit volume of ferrocement element, including

rods, mesh and mortar. The minimum recommended steel content is 380 kg/m3 while the maximum is 650 kg/m3. The steel content expressed as percentage steel area in the cross section of the ferrocement element is in the range of 2.0% - 6.5%. Specific surface measures the dispersion and fineness of the meshes and their ability to control cracking. The total surface area of the mesh divided by the volume of the ferro cement element containing it is in the range 1.8 - 3.0 cm2 /cm3. The ability to build hull, decks, bulkheads, floors and engine bearers, fish tanks and bulwarks in one piece resulting in a monolithic structure of immense strength which actually increases with age is an important advantage of ferrocement. Ferrocement craft can be built without highly skilled labour. No expensive plant is needed as in the case of steel construction and to a lesser extent with timber construction. It is not necessary to use a mould for ferrocement construction as in the case of building with FRP as no temperature control is necessary. Local manufacturing can be done without sophisticated facilities. The raw materials necessary for ferrocement construction are easily available in most countries. FRP raw materials are relatively expensive and requires storage facilities. Ferrocement hull costs 20 - 25% less than a similar hull in timber or steel. Overall saving may not be more than 4 - 7%. Unlike steel it is immune to rust and corrosion and will not rot like timber. It is resistant to marine borers. Ferrocement has proven aging qualities. No painting required except to enhance appearance. Because of mesh reinforcement, it will have tensile strength in all directions. The tensile strength in wood is reduced due to numerous fastenings whereas ferrocement do not have any fastenings. Compressive strength without reinforcement is 4200 psi after 7 days and 12,225 psi after 28 days and continues to increase with age. The specific gravity of ferrocement is 2.6, FRP is1.6 and that of wood with fastenings is 0.9. Over 40 ft., when skin thickness of other materials has to be increased the ferrocement boat compares favorably with other vessels – wood, FRP and steel, because no heavy internal frames are required. Damaged area can be chipped away until surrounding area is fine. Ferrocement mix applied both in interior and exterior area is left little pruned and finally ground off. In addition, ferrocement has good heat insulation properties (Fyson, 1973). Steel

Steel is mainly used to construct hulls of large vessels mainly beyond 50 m in length. A

steel hull has a relatively thin outside shell and the minimum thickness is 2 - 3 mm. Mild steel is commonly used to construct fishing vessels where the carbon content is 0.15 to 0.30%. Steel vessels have good strength, elasticity and durability. Steel can be easily bent and twisted so that

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larger designs/sections can be fabricated easily with less wastage. The specific gravity of steel is 7.84 where the weight is comparatively more than wood, aluminium and FRP vessels. Steel is prone to corrosion and anticorrosive paints are essential for the hull protection. Seawater corrosion of steel can only be controlled by external factors rather than by the composition of steel since none of the common alloying elements has any commercially significant influence on corrosion. For small boat construction steel is not an efficient material.

In tropical environments where corrosion is a major problem the lower limit of the length

of fishing vessels are often 15 m or more. Steel hulls may be prefabricated in section, which adds to its many advantages. The steel hull structure consists of rolled plates and profiles. Plates appear in different sizes and different thicknesses. The thinner plates (3 -6 mm) are mostly 5 - 8 m long and 1.2 - 2 m wide. Thicker plates up to 30 mm and more are up to 12 m long 2.5 m – 3 m wide. The thicknesses are mostly sub - divided by half millimeters (3, 3.5, 4, 4.5). For greater thickness over 20 mm however the difference is one millimeter.

Steel hulls are constructed either in the longitudinal type or transverse type or

longitudinal to transverse type according to one of the three systems. Longitudinal construction is characterized by members stiffening the plating in the fore and aft direction. This type of construction is used in very large merchant vessels and sometimes on smaller boats. It gives a reduction in hull weight compared to other types of construction. In transverse type of construction, the main stiffening of the shell and deck plating is arranged in transverse planes at a distance of about 500 - 650 mm. The appropriate transverse elements are floors, frames and deck beams connected to each other by brackets. These types of construction are used most frequently in small and medium - sized vessels and steel fishing vessels are practically built in conformity with the transverse system. The mixed or transverse - longitudinal system is used on ships with a length of over about 100 m up to some 250 m. It combines the advantage of basic systems but due to technological reasons is not used in smaller vessels. Environmental impacts of major boat building materials in aquatic system

Despite of its obvious advantages, all boat building materials are susceptible to the effects

of marine environment, for example glass fibres are the most selected material for boat construction, which are vulnerable to the effects of sunlight in marine conditions. Glass fibre is prone to osmosis and gelcoat gets faded in sunlight resulting in the attack of UV radiation. Aluminum alloys are prone to corrosion if untreated or damaged. When new alloys are exposed, an oxide layer is formed on their surface but this oxide layer does not protect the alloy in the long term when exposed to marine environments. Periodically the paint system will need to be removed in areas of stress and the corrosion treated. Careful inspection on an annual basis of all weld seams helps in early identification of the occurrence of this problem. Aluminum reacts with some copper-based antifouling paints causing serious corrosion in environmental conditions. Therefore, antifouling containing metallic copper or cuprous oxide should never be used on aluminum, whilst copper thiocyanate based antifouling can be used if the aluminum is primed properly.

The most common form of corrosion in steel is rust. Such a reaction will take place only in

the presence of water. The marine environment is therefore an ideal place for rust to occur. Due to the high flexibility and strength of steel it is hard to break, but impact damage may well result

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in a dent owing to the metal stretching and deforming locally. This can present problems for a protective coating, which may not be so flexible.

The fibrous nature of timber means that it has a tendency to absorb moisture from the

atmosphere, and swell and contract to varying degrees depending on the type of construction. For a varnish or paint coating to stay intact it has to be quite flexible in nature. Moisture content in wood allows the growth of fungal spores, which leads to rotting and decay. Wood can also be subjected to the attack of marine borers, which eat the wood fibers. Therefore, it needs to be protected by good quality preservatives and coatings. Many different woods can be used, which can differ immensely.

Strength comparison of boat building materials

Material Specific weight

Tensile strength

Compressive strength

Elastic modulus

1b/ft3 tonne/m3 kN/m2 × 10 kN/m2 × 10 kN/m2 × 10

FRP (CSM) 94 1.5 100 100 6 (WR) 106 1.7 240 170 14 Wood spruce 42 0.7 55 40 8 Ply 40 0.65 16 12 11 Aluminium 170 2.7 120 85 70 Steel 485 7.8 210 190 200

A comparative table showing the carbon consumption in the production of these materials

Material Net carbon emissions (kg C/metric) 1

Net Carbon emissions including Carbon storage within material (kg C/ metric ton)2

Framing Lumber 33 -457 Medium density fibre board 60 -382 Steel 694 694 Aluminium 4532 4532 Plastics 2502 2502

Net carbon emissions in producing 01 ton of material (OECD, 2010). Net carbon emission

of wood and its relative materials (unit metric ton) were less and found to be negative where the maximum carbon emission was for aluminium followed by plastic.

While considering the environmental and economic sustainability of different boat building material, wood is an ideal material still preferred for marine boat construction. Wood is a

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functionally efficient material which reduce carbon footprint thereby reducing the environmental impact and simultaneously balance the cost objective. Environmental impact of any material (proposed for prolonged use) can be evaluated through Life cycle assessment procedure or LCA. The environmental impact of wood from the very first state of harvesting to the end of the product was studied and compared with other materials and found that wood as a material for boat construction contributes less pollution to the environment compared to concrete, steel, aluminium etc. (Fagerblom 2017). Høibø et al, 2015, explained that energy consumed by all the processes as embodied energy (EE) and Hsu, 2010 reported that EE of concrete, which is the highest, of 12.5MJ/kg EE, steel is 10.5 MJ/kg EE and the lowest is wood with 2.00MJ/kg EE. Studies have found that wood products have less embodied energy and are more environmental friendly as they are involved in less carbon footprint as well as air and water pollution. Furthermore, residues of wood industries are utilized in either by-product manufacturing or fuel and clean bio-energy. As forests act as carbon sink and prevent climate change and green-house gas, increasing wood use ensures sustainable development by reducing emission, increasing renewable wood use, and thus helping national economy (Fagerblom 2017). References/suggested reading Bose, S. and Vijith, V., 2012. Wooden Boat Building for Sustainable Development. International Journal of

Innovative Research and Development (ISSN 2278–0211), 1(10), pp; 345-360

Coackley, N., 1991. Fishing Boat Construction, 2: Building a Fiberglass Fishing Boat (No. 321). Food & Agriculture Org

Fagerblom, A. 2017. Member State Reach Agreement Regarding Forest Carbon Sinks – Finland Need To Continue To Find A Reasonable Solution. Article. Published by: Finnish Forest Forestry. Read 26.11.2017

Fyson, J. (1973) FAO Investigates Ferrocement Fishing Craft, Fishing News (Books) Ltd., Surrey: 200 p

Høibø, O., Hansen, E. and Nybakk, E., 2015. Building material preferences with a focus on wood in urban housing: durability and environmental impacts. Canadian Journal of Forest Research, 45(11), pp.1617-1627

Hsu, S.L., 2010. Life cycle assessment of materials and construction in commercial structures: variability and limitations (Doctoral dissertation, Massachusetts Institute of Technology)

Meenakumari, B. ed., 2009. Handbook of fishing technology. Central Institute of Fisheries Technology

Shipbuilding, O.C.W.P.O., 2010. Environmental and climate change issues in the shipbuilding industry. Environmental and climate change issues in the shipbuilding industry

Sleight, S., 1988. Modern boat building: materials and methods. International Marine Publishing

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Basic Principles of Design of Fishing Gears and their Classification

M.R. Boopendranath Principal Scientist - Retd., Fishing Technology Division, ICAR-CIFT, Kochi


Introduction

Fishing gears vary greatly in their structure, materials used, principles of capture process and methods of operation. Design and development of harvesting systems based fish behaviour, engineering studies, system analysis and model studies, have been taking place in the recent decades.

Basic principles of fishing gear design and construction

With the development and wider availability of synthetic gear materials, recent advances in vessel technology, navigational electronics, gear handling machinery, fish detection methods and fish behaviour studies, large-scale changes have taken place in the design, fabrication, operation and catching capacity of modern fishing gears such as trawls, purse seines and long lines. Widely used traditional fishing gears such as entangling nets, hook and lines and traps have also benefited by way of design upgradation and efficiency improvement in the recent years. New innovative fishing systems such as electrical fishing, light-assisted fishing, FAD-assisted fishing and fish pumps have also been developed and accepted in different parts of the world. Design process for fishing gear has been greatly influenced in the recent years by the resource management and conservation, environmental safety and energy efficiency imperatives.

Principal mechanisms of fish capture

Principal mechanisms used in fish capture are (i) filtering e.g., trawls, seines and traps; (ii) tangling e.g., gill nets, entangling nets and trammel nets; (iii) hooking, e.g., hand line, long line and jigging; (iv) trapping, e.g., pots and pound nets; (v) pumping, e.g., fish pumps. Main behaviour controls used in the fish capture process are (i) attraction, e.g. bait, light, shelter; (ii) repulsion or avoidance reaction, e.g. herding or guiding by netting panels as in set nets and trawls or sweeps and wires as in boat seines and trawls.

Fishing gear design

Design process involves a divergent phase when analysis of the situation, statement of needs, specifications, standards of operation and constraints are spelt out; a transformational phase which includes generation of design ideas; and a convergence phase during which an evaluation in terms of objectives of design, utility and economic viability, prototype development, testing and evaluation takes place (Fig. 1). A preliminary design thus generated is further refined based on additional information through an iterative cycle until final design is adopted.

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Fig. 1. Design process

Model testing

Model testing is increasingly used for design evaluation of the existing commercial fishing gear designs with a view to optimise their design parameters and for development of newer designs. In model testing, a scaled down model of the fishing gear is tested in a flume tank in order to study its behaviour and estimate working parameters. Principles of similarity are then used to assess the dimensions, specifications and characteristics of the full-scale version based on model studies. The fishing gears are further evaluated using full-scale version through statistically designed comparative field trials with a gear of known fishing efficiency and operational parameters are verified through gear monitoring instrumentation and underwater observations.

Factors affecting fishing gear design

Important factors which influence the design of fishing gears are (i) biology, behaviour and distribution of target species; (ii) fishing depth, current and visibility; (iii) sea bottom conditions; and (iv)other factors such as the scale of operations, size and engine power of fishing vessel, energy conservation objectives, selectivity and resource conservation objectives.

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Biology, behaviour and distribution of target species

Choice and design of fishing gear is greatly influenced by biological characteristics such as body size and shape, feeding habits and swimming speed; behaviour in the vicinity of fishing gear and during capture process; spatial distribution and aggregation behaviour of the target species.

Body size and shape determine the mesh size required to enmesh and hold the fish in gill nets and the mesh size to retain the target size groups of the species without gilling in the trawls, seines and traps. Body size is also related to the tensile strength requirements for the netting twine in gill nets and hook size and lines in hook and line. Body size is again directly proportional to the swimming speed which is a significant attribute to be considered in the fishing success of dragged gear. Feeding habit of the target species is more important in passive fishing methods like hook and line and traps where the fish is attracted by the bait and in the active fishing methods like troll line used for catching predatory fishes.

Consideration of the swimming speed of the target species is important particularly in the active fishing methods like trawling, seining and trolling. Fishes are known to sustain a cruising speed of 3-4 body lengths per second for long periods without fatigue and burst speeds of 10 body lengths per second for short duration. During burst speeds reserve energy supplies in the fish muscle is used up. Fish in front of the trawl mouth will be eventually caught if the trawling speed is greater than the cruising speed of the fish. Behaviour of different species might vary when they turn back into the trawl. Such differential behaviour makes it possible to separate the different species using separator panels inside the trawl. Selective capture of the slow moving crustaceans providing opportunity for the fast swimming non-target finfishes to escape, could be possible by controlling the towing speed and minimising the longitudinal length of the trawl net.

Behavioural differences between fish and crustaceans and size differences between them could be used in the design of selective trawl designs. In such designs, rigid grids are placed at an angle, before codend. Small sized prawns move through the grid into the codend while fish and other non-target species are deflected by the grid and are released through an escape chute. Such devices are sometimes called Trawl Efficiency Devices as they reduce the sorting time and thus increase the efficiency of operations. Protected species like turtles are allowed to escape in a similar way using Turtle Excluder Devices (TEDs).

Large mesh trawls and rope trawls, in which front trawl sections are replaced with very large meshes or ropes in order to reduce drag, make use of the principle of repulsion or herding to guide the finfish into trawl codend. In the conventional trawling systems, herding effect by the otterboards, wires and sweeps and sand-mud cloud created by the boards on finfishes in between the boards, is made use of, to improve the catch rate by increasing the effective sweep area. Long leader nets placed in the path of migratory fishes guide them into large set nets operated in Japan. Tendency of some fishes to aggregate towards light is used in squid jigging, light-assisted purse seining and dip net operations. Behaviour of fishes like tuna to aggregate around the floating objects, is utilised successfully in FAD-assisted purse seining.

Catching efficiency is maximised when the vertical opening of the trawl mouth, vertical dimension in gill nets, and the catenary of the main line of the long line with branch lines and hooks, coincide with the vertical range of the layer of maximum fish abundance. Hence, knowledge of the vertical distribution of the target species could be used to optimise the

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horizontal and vertical dimensions of the netting panels in gill nets, main line catenary in long lines and mouth configuration in trawls.

Some species of fish are sparsely distributed either singly or in small groups and thus exhibit a pronounced patchiness, while some others form dense schools. Sparsely distributed scattered fish are more efficiently caught by passive fishing methods such as gill netting and long lining, where as schooling fishes are effectively caught by purse seining and aimed midwater trawling.

Fishing depth, currents and visibility

Hydro-acoustic pressure increases approximately at the rate of one unit atmospheric pressure (1 bar) for every 10 m depth. Buoyancy elements used in the deep sea fishing gears such as deep sea trawls, gillnets and bottom vertical lines have to be strong enough to withstand the pressure at the fishing depth. Compressible buoyancy elements that are simple, light and cheap can only be used in the surface operated gears such as seines and surface gillnets as they absorb water and loose their buoyancy in deeper waters.

Prevailing strong currents in the fishing ground may restrict the choice of fishing gears to longlines and gillnets which are less affected by currents. Light levels at the fishing depth could influence the fishing success, as vision of fish is affected by light levels. In passive fishing gears such as gillnets, visibility of netting panel adversely affects fishing efficiency. Visibility is again negatively indicated in hook and line operation while in light-assisted jigging, controlled lighting plays an important part. Visibility is also important in effective herding during the capture process in trawls and in large pound nets and trapping enclosures where leader nets are used.

Sea bottom conditions

Rough sea bottom conditions limits the operation of most of the fishing gears close to the ground except handlines, vertical longlines, bottom vertical longlines and traps. Trawling on rough bottom requires special rigging such as bobbin rig or rock hopper rig, improvements in trawl design to minimise gear damage or loss and selection of appropriate otter boards.

Other factors

Choice of fishing gear and their design features will also be influenced by the scale of operations, size and engine power of fishing vessel, energy conservation objectives, selectivity and resource conservation objectives, catch volume requirements, operational and handling requirements of the gear, prevailing weather conditions, skill required for fabrication, maintenance and operation, material availability, local traditions and economic considerations. In dragged fishing gears such as trawls, total drag of the trawl system should not exceed the available towing force of the vessel, which is total towing force less towing force expended in overcoming hull resistance.

Fishing gear construction

Fishing gear materials are either of textile origin such as netting, twine and ropes or of non-textile origin such as floats and sinkers, hooks and jigs and sheer devices. Most of the widely used fishing gears such as trawls, encircling nets, gillnets and entangling nets, lift nets, falling gears and many of the trap nets extensively use netting panels as a restrictive barrier in their

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design and construction. Notable exceptions are longlines, handlines, squid jigs, troll lines and some of the pots and creels.

Shaping of netting

Each netting panel used in the construction of fishing gear can be derived from one or more sections of particular geometric shapes such as rectangle, trapezium or triangle each with a uniform mesh size and twine specifications (Fig. 2 & 3). The shape of these component pieces constituting the netting panels is achieved by increasing, decreasing or maintaining the number of meshes in the N-direction or T-direction (Fig. 4). This is done by shape cutting the pieces from machine made webbing.

Fig. 2. Basic trawl design illustrating constituents of netting panels

N-cut, T-cut and B-cut

Three types of cuts viz., N-cut, T-cut and B-cut are used to shape the netting (Fig. 4)

(i) N-cut through both the twines at one side of the knot advances by one mesh in the N-

direction. If the knot in N-cut is undone, the mesh is opened. Hence, it has to be

stabilised in a seam or mend. This is also called point-cut or P-cut.

(ii) T-cut through both the twines at the top or bottom of the knot, advances by one mesh

in the T-direction. The knot in T-cut when undone gives a clean mesh. This is also

called Mesh cut or M-cut.

(iii) B-cut through one twine at a knot advances by half a mesh in both N and T directions.

The knot in B-cut when undone forms a fly mesh or dog-ear. This is also called Bar cut.

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B-cuts in the same direction forms an oblique taper in which the number of meshes in

the N-direction is equal to that in the T-direction.

Fig. 3. Design of a 29 m shrimp trawl

Fig. 4. Types of cuts used to shape netting

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Taper ratio

Netting sections required to make up the gear panel are cut according to pre-calculated taper ratio from the machine made netting.

Taper ratio R : Mt / Mn,

where Mt is the number of meshes in the T-direction and Mn is the number of meshes in the N-direction.

Cutting rate

Cutting rate is regular repeated cycle of N-cuts; T-cuts; B-cuts; N-cuts and B-cuts; or T-cuts and B-cuts made in the correct proportion to obtain the required taper ratio. Based on taper ratio cutting rate is calculated as given in Fig. 5.

Fig. 5 Calculation of cutting rates

In order to keep the taper cut even, the number of B-cuts and N-cuts/T-cuts in each cutting cycle should be reduced to the smallest possible integers. The N-cut and B-cut or T-cut and B-cut, as the case may be, should be mixed uniformly, maintaining the correct taper ratio to obtain the smoothest taper possible. Netting usage can be economised by careful planning of the cuts of the complementary pieces used in gear construction. Table 1 gives cutting rates for various common taper ratios.

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Table 1. Cutting rates

Hanging

Actual shape of a mesh or netting panel is determined by the process of hanging it on to a rope frame.

Hanging coefficient, Eh =

Hung length of the netting / Fully stretched length of the netting

Resultant vertical hanging coefficient, Ev = √1-Eh2

Hung depth of a panel of netting in meters is given by

√(1-Eh2).n.m.0.001

where √(1-Eh2)is the resultant vertical hanging coefficient;

n is the number of meshes in depth and m is the mesh size in mm

Effect of different hanging coefficients on the shape of netting and mesh opening is illustrated in Fig. 6. Hanging or mounting of netting is illustrated in Fig. 7.

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Fig. 6. Effect of different hanging coefficients on shape of netting

Fig. 7. Illustration of mounting

Assembly of netting

The various constituent pieces of netting panels prepared by shape cutting, are assembled by either joining or seaming. Joining requires braiding an extra row connecting the two panels. When the edges to be joined have the same number of meshes and same mesh size, joining is made mesh to mesh. When the two pieces to be joined has the same stretched width but different mesh size, additional or ‘take up’ meshes in the panel of small mesh size are interspersed uniformly among the meshes of other panel.

In seaming, one or several meshes on the edge of each panel are re-joined together by lacing. In trawl fabrication, seams are used for assembling the corresponding pieces of the two panels to be joined longitudinally. It is generally done by taking up 3-6 meshes on each edge of the trawl panels, using double twine, seizing by half hitches approximately every 50 cm, after 4 or 5 passages through meshes. Fig. 8 shows pictorial view of a fully assembled two panel demersal trawl.

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Fig. 8. Pictorial view of a two-seam demersal trawl

Design drawings and specifications of fishing gears

Design drawing

Design drawing of the fishing gear should provide all information relating to the size, shape, material and construction using recognised nomenclature and symbols, in order to permit the construction of identical fishing gears from the same drawing. In the design drawing net panels are drawn to scale according to theoretical hung length and hung depth.

Hung length of the panel in m = Mt.m.Eh.0.001

Hung depth of the panel in m = Mn.m. √(1-Eh2) . 0.001

where Mt = number of meshes in T-direction, Mn = number of meshes in N-

direction, m = mesh size in mm, Eh = horizontal hanging coefficient, and √(1-Eh2)

= vertical hanging coefficient.

Netting panels not drawn to scale are marked accordingly. Ropes, floats and other rig items are generally not drawn to scale. All measurements are given in SI units. Larger dimensions are expressed in m to the nearest 0.01m and smaller dimensions in mm to the nearest 1 mm without specifying units.

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According to ISO (1975) recommendations, dimensions in length of netting panels in trawl and seine net designs, are represented as fully stretched length (Ev = 1.0) and in width as half stretched length (Eh = 0.5). In gill net and entangling net designs, length is drawn according to the length of float line. Depth is drawn according to the length of gavel lines, if they are present or according to the fully stretched netting in depth (Ev = 1.0). In surrounding net designs such as purse seines and lampara net, length is drawn according to the length of float line and depth according to the fully stretch netting in depth. For designs of traps, pots, dredges and lines and for rigging and auxiliary components of the design of all gear designs perspective drawings and projections are used to represent the design details.

Specifications

Specifications and details given in the design drawing for nets may include:

i. Twine: material; size in R-tex; construction.

ii. Rope: material; size in R-tex or dia.

iii. Netting panel: number of meshes in T-direction on upper and lower edges; number of

meshes in N-direction on either side; cutting rates for all tapered edges; mesh size in

mm; hanging coefficient; special features such as colour and double selvedge.

iv. Joining methods.

v. Float line length in m.

vi. Lead line length in m.

vii. Side line length in m.

viii. Ground rope construction.

ix. Otter board: type; dimensions; weight.

x. Rigging: connecting ropes; hardware components; floats; sinkers.

xi. Scale of drawing.

xii. Title indicating the class of design.

xiii. Vessel: Loa; hp.

xiv. Target species.

xv. Origin of design.

Estimation of weight of netting

Information on weight of netting is required for ordering netting requirements and for determination of underwater weight of netting for rigging purposes.

The first step is to have the complete design drawing including specifications. Every net is composed of a number of sections of particular geometric shapes such as rectangle, trapezium and triangle each with a uniform mesh size, twine size and material specification. Length of the twine used in each of the netting sections are estimated as below:

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Lt = K.[((Mt1+Mt2)/2).Mn].2m.10-3

where Lt = length of twine used in m; Mt1 and Mt2 = number of meshes in width

along top and bottom edges; Mn= number of meshes in depth; m= stretched mesh

size in mm; K= correction factor for length of twine used in a knot (length of twine

used in a mesh / 2m).

Correction factor K is usually within the range of 1.1 -1.5, depending on twine diameter/mesh size ratio and type of knot in knotted netting and is equal to 1.0 for knotless netting. From the length of twine thus estimated weight of the netting panel is determined as below:

Weight of the netting in kg, Wn = Lt.R-tex.10-6

where Lt = length of twine in m; R-tex = linear density of netting twine (g.km-1)

Alternatively, if tables of weight in grams per square meter of fictitious area (stretched length x stretched width) for particular specifications of netting are available, the weight of netting panel in grams could be estimated by multiplying it with the fictitious area of panel in sq.m. Fridman (1986) has given such tables for polyamide netting.

Weight of netting in seawater, Wns = Wn .(1-(1025/d))

where d = the specific mass of the netting material in kg.m-3; Wn = weight of

netting in air

Classification of fishing gears

Several systems of classification of fishing gears have been developed based on the principles of capture, design and technical features and operational methods. Fishing gears whether primitive or sophisticated use five mechanisms in the capture process viz., gilling and tangling (e.g. gill nets and trammel nets), trapping (e.g. traps, pound nets), filtering (e.g. trawls, seines and other net fishing systems), hooking and spearing (e.g. hook and line, harpoons) and pumping (e.g. fish pumps). Fishing gears are either passive like gill nets and entangling nets, hook and line and traps or active like trawls, seines and troll line. Active fishing systems are generally energy intensive and more productive than passive gears. Based on the degree of selectivity, the fishing gears are more selective like gill nets, hook and line and traps or less selective like trawls, seines and entangling nets. Depending on the sector in which they are used, there are small-scale or artisanal fishing gears covering a wide variety of traditional low energy systems of fish capture, and large-scale industrial mechanised fishing systems including purse seining, trawling and automated long lining. Based on the water bodies in which they used there are inland fishing gears, including riverine, estuarine and reservoir gears, and marine fishing gears. Based on the area of operation, there are coastal, offshore and deep sea fishing gears and depending on the fishing position in the water column there are pelagic, midwater and demersal or bottom fishing gears.

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Most widely used systems of classification are based on the principles of fish capture, historical development and structural differences. Brandt (1959) grouped the fishing gear and methods into 13 categories viz., fishing without gear, wounding gear, stupefying methods, line fishing, fish traps, traps for jumping fish, bag nets with fixed mouth, dragged gear, seine nets, surrounding nets, dip or lift nets, falling nets, and gill nets and tangle nets. In the International Standard Statistical System of Classification adopted by FAO for fishery statistics, fishing gears are grouped into fourteen categories according principles of capture and sub-grouped according structure of the fishing gear, leaving scope for further additions in future. Primary categories include surrounding nets, seine nets, trawls, dredges, lift nets, falling gear, gill nets and entangling nets, traps, hooks and lines, grappling and wounding gear, harvesting machines, miscellaneous gear, recreational gear and gear not known or not specified (Nedlec, 1982)(Table 2). Major classes of fishing gears are categorised here as (i) active, (ii) passive and (iii) other miscellaneous fishing gears.

Table 2: International Standard Statistical Classification of Fishing Gear (ISSCG)

Gear Categories Abbreviation ISSCFG Code

SURROUNDING NETS 01.0.0 With purse lines (purse seiners) PS 01.1.0 One boat operated purse seines PS1 01.1.1 Two boats operated purse seines PS2 01.1.2 Without purse lines LA 01.2.0 SEINE NETS 02.0.0 Beach seines BS 02.1.0 Boat seines SV 02.2.0 Danish seines SDN 02.2.1 Scottish seines SSC 02.2.2 Pair seines SPR 02.2.3 Seine nets (not specified) SX 02.9.0 TRAWLS 03.0.0 Bottom trawls 03.1.0 Beam trawls TBB 03.1.1 Otter trawls OTB 03.1.2 Pair trawls PTB 03.1.3 Nephrops trawl TBN 03.1.4 Shrimp trawl TBS 03.1.5 Bottom trawls (not specified) TB 03.1.9 Midwater trawls 03.2.0 Otter trawls OTM 03.2.1 Pair trawls PTM 03.2.2 Shrimp trawls (not specified) TMX 03.2.9 Otter twin trawls OTT 03.3.0 Trawls (not specified) OT 03.4.0 Pair trawls (not specified) PT 03.5.0 Other trawls (not specified) TX 03.9.0 DREDGES 04.0.0

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Boat dredges DRB 04.1.0 Hand dredges DRH 04.2.0 LIFT NETS 05.0.0 Portable lift nets LNP 05.1.0 Boat-operated lift nets LNB 05.2.0 Shore-operated stationery lift nets LNS 05.3.0 Lift nets (not specified) LN 05.4.0 FALLING GEAR 06.0.0 Cast nets FCN 06.1.0 Falling gear (not specified) FG 06.9.0 GILLNETS AND ENTANGLING NETS 07.0.0 Set gillnets(anchored) GNS 07.1.0 Drift nets GND 07.2.0 Encircling gillnets GNC 07.3.0 Fixed gillnets(on stakes) GNF 07.4.0 Trammel nets GTR 07.5.0 Combined gillnets-trammel nets GTN 07.6.0 Gillnets and entangling nets (not specified) GEN 07.9.0 Gillnets (not specified) GN 07.9.1 TRAPS 08.0.0 Stationary uncovered pound nets FPN 08.1.0 Pots FPO 08.2.0 Fyke nets FYK 08.3.0 Stow nets FSN 08.4.0 Barriers, fences, weirs, etc FWR 08.5.0 Aerial traps FAR 08.6.0 Traps (not specified) FIX 08.9.0 HOOK AND LINES 09.0.0 Handlines and pole-lines (hand operated) LHP 09.1.0 Handlines and pole-lines (mechanized) LHM 09.2.0 Set longlines LLS 09.3.0 Drifting longlines LLD 09.4.0 Longlines (not specified) LL 09.5.0 Trolling lines LTL 09.6.0 Trolling lines (not specified) LX 09.9.0 GRAPPLING AND WOUNDING GEAR 10.0.0 Harpoons HAR 10.1.0 HARVESTING MACHINES 11.0.0 Pumps HMP 11.1.0 Mechanized dredges HMD 11.2.0 Harvesting machines (not specified) HMX 11.9.0 MISCELLANEOUS GEAR MIS 20.0.0 RECREATIONAL FISHING GEAR RG 25.0.0 GEAR NOT KNOWN OR NOT SPECIFIED NK 99.0.0 Source: Nedlec (1982)

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Active fishing gears

Fishing gears such as surrounding nets, seine nets, trawls, dredges, pole and line, jigging lines, lift nets and falling gear that are actively operated, comes under this category.

Surrounding nets

Surrounding nets are roughly rectangular walls of netting rigged with floats and sinkers which after detection of the presence of fish are cast to encircle the fish school. Surrounding nets are generally operated in the surface layers.

Purse seines

Purse seines are the predominant type of surrounding nets, in which the bottom of the net is closed after encircling the fish school, by a purse line which prevent fish from escaping downwards by diving (Fig. 9). Based on the number of vessels used in operation there are one-boat and two purse seines. Based on the target species there are anchovy purse seine, sardine purse seine, mackerel purse seine, cod purse seine and tuna purse seine. Based on the scale of operations there are small, medium and large purse seines. Surrounding net without purse line, like Lampara net, are operated in small scale sector (Fig. 10).

Fig. 9 Purse seine Fig. 10 Lampara net

Seine nets

Seine net is a long wall of netting with or without a bag, supported by floats and sinkers, which are operated by surrounding areas of water with potential catch. The net is operated by ropes attached to the end of wings which are used for hauling and for herding the fish. They are usually operated in the coastal or shallow waters where bottom and/or surface act as natural barriers. Seines which are operated from the boat are called boat seines. Danish seine (Fig. 11) is operated on the bottom from a single boat, consists of a bag and wings attached to long ropes set in water so as to cover a large area in order to herd the fishes therein into the net mouth. Seines operated from the shore are called shore seine or beach seine (Fig. 12). An example is Rampani net operated in south-west India.

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Fig. 11 Danish seine Fig. 12 Beach seine

Trawls

Trawl nets are conical bag nets with two wings and a codend where catch is concentrated, operated by towing from one or two boats.

Based on the position in water column where they are operated, trawls are classified into bottom trawl and midwater or pelagic trawl. Based on the opening of the mouth they are grouped into beam trawl where mouth is kept open by means of a rigid wooden or steel beam (Fig. 13); otter trawls where otter boards are used for horizontal spread of trawl mouth (Fig. 14). Depending on the number of boats used there are one-boat trawls (Fig. 14; Fig. 16) and two-boat trawl or pair trawl or bull trawl (Fig. 15; Fig. 17). Based on the number of trawls operated from a single vessel, there are double rig trawl system where two nets are operated from outrigger booms (Fig. 18); triple trawl system where three nets are operated at the same time (Fig. 19) and quad rig system where two nets each are operated from two out rigger booms (Fig. 20).

Fig. 13. Beam trawl Fig. 14. One-boat bottom otter trawl

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Fig. 15. Two-boat bottom otter trawl

Fig. 16. One-boat midwater trawl

Fig. 17. Two-boat midwater trawl Fig. 18. Double rig trawl

Fig. 19. Triple rig trawl Fig. 20. Quad rig trawl

Dredges

Dredges are dragged gear, with an oblong iron frame with an attached bag net, operated on the bottom usually for collecting shellfish. They are either operated from boat or in shallow waters by hand (Fig. 21).

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Fig. 21. Dredge

Hook and Line (actively operated)

Fish are enticed by edible or artificial bait or lure which simulates the appearance and movement of the natural prey, and are finally held by the hook concealed in the bait or lure. The hook is connected to a line or snood. The fish is also held by the piercing action of hooks or jigs passing nearby. Important types of hooks and lines which are actively operated are pole and line (Fig. 22) which are either worked manually or mechanically; jig lines which are operated either manually or by powered jigging machines for squids attracted by light (Fig. 23) and troll lines operated for predatory fishes with hooks having natural or artificial baits, trailing behind the running vessel usually in the surface layers (Fig. 24).

Fig. 22. Pole and line Fig. 23. Squid jigging

Fig. 24. Troll line

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Lift nets

Lift net consists of horizontal netting panel or a cone-shaped bag with the mouth facing upwards, which are submerged and lifted either manually or mechanically to filter the fish in the overlying water column.

There are shore operated lift nets which are operated from stationary installations along the shore (Fig. 25) and boat-operated lift nets which are operated from one or several boats (Fig. 26).

Fig. 25. Shore-operated lift net Fig. 26. Boat-operated lift net

Falling gear

Falling gear is cast over the area where fish is available, then gathered and lifted to collect the fish. Many of the artisanal fishing gears such as cast net, cover pot and lantern net belong to this category (Fig. 27).

Fig. 27. Cast net

Passive fishing gears

Gillnets, entangling nets, traps and many of the hooks and lines fall under the category of passively operated fishing gears.

Gill nets and entangling nets

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Gill nets are rectangular walls of netting kept erect by means of floats and sinkers and positioned in the swimming layer of the target fish, which catch the fish by holding them in the mesh by gilling.

Depending on method of operation gill nets are classified into drift gill nets, set gill nets and encircling gill nets. Drift gill nets are operated in the surface layers and drift with the current either separately or with the boat to which it is tethered (Fig. 28). Set gill nets or anchored gill nets are fixed to the bottom or at a distance above bottom by means of anchors or ballast (Fig. 29). Fixed gill nets operated in the shallow coastal waters are fixed by means of stakes and the catch is collected during low tide. Encircling gill nets are operated in the surface layers in coastal areas. After encircling the fish, noise and other vibrations are used to drive the fish towards the net so that they are either gilled or entangled.

Fig. 28. Drift gill net Fig. 29. Bottom set gill net

Based on the structure, there are simple gill nets with a single wall of netting supported by floats and sinkers and triple-walled nets called trammel net (Fig. 30). The trammel net generally operated as bottom-set, has two outer walls which are of larger mesh size and a loosely inner wall is of smaller mesh size. The inner wall intercepting a fish approaching through the large mesh on the outer wall, forms a pouch after passing through large mesh on the outer wall on the opposite side and hold the fish securely. In the combined gill net-trammel net lower part fabricated as trammel and the upper part as simple gill net.

Entangling nets loosely hung single or multi-walled netting held vertically in water by floats and sinkers, which catch fish entangling rather than enmeshing. Nets are usually attached end to end to form large fleets.

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Fig. 30. Trammel net

Traps

Traps are passive fishing gears with enclosures to which the fish are lured or guided and from which escape is made difficult by means of labyrinths or retarding devices like funnels or constrictions. A wide range of traditional fishing gears is grouped here.

Pots are cages or baskets made from materials like wood, wicker, metal rods, wire netting and reinforced plastic, designed to catch fish, crustaceans or cephalopods by enticing them with baits or shelter spaces (Fig. 31). They are provided with one or more entrances of appropriate gape. They are usually set on the bottom singly or in series connected by ropes and position marked by buoys.

Stationary uncovered pound net called set nets in Japan, are large nets, anchored or fixed on stakes. A leader net is kept at an appropriate angle to the swimming direction of migrating fish schools so as to guide them to enclosures with retarding devices and closed at the bottom by netting (Fig. 32).

Fig. 31. Lobster pot Fig. 32. Set net

Fyke nets used in shallow waters consists of a cone-shaped bag of netting with ring shaped rigid structures to maintain cylindrical shape of the net body and is provided with wings to lead the fishes into the bag. The fyke nets are fixed to the bottom by stakes or ballast and are operated separately or in series. Stow net are conical bag net operated in shallow waters and estuaries where tidal currents are strong. The mouth of the net is kept open against the current by means of stakes driven to the bottom or by means of floats and ballast (Fig. 33). Barriers, fences, weirs and corrals are trapping enclosures made of indigenous materials and operated in tidal waters (Fig. 34). Aerial traps are systems in which fish like mullets, which jump out of water on disturbance and flying fishes, attracted by light are caught in floating enclosures or rafts. Verandah net and boat operated aerial traps are examples in this category (Fig. 35).

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Fig. 33. Stow net Fig. 34. Corral

Fig. 35. Aerial traps

Hooks and Lines (passively operated)

Fish are enticed by edible bait or lure and are finally held by the hook concealed in the bait or lure. The hook is connected to a line or snood. They are operated either singly or in large numbers. Important types of hooks and lines which are passively operated are hand lines operated in the small-scale sector and long lines where a large number of hooks are attached to the mainline by means of branch lines. Long lines when set in surface and midwater with freedom to drift with the current are called drifting long lines (Fig. 36); when set close to the bottom are called bottom-set long lines (Fig. 37); when set vertically, they are called vertical long lines (Fig. 38); when combining the properties of bottom and vertical long lines they are called bottom vertical long lines (Fig. 39).

Fig. 36. Drift long line Fig. 37. Set long line

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Fig. 38. Vertical long line Fig. 39. Bottom vertical long line

Miscellaneous fishing gears

Fishing without gear

Gathering of animals by hand picking or by simple implements such as shovels, picks or knives, with or without the support of diving equipment; and fishing by using trained animals or birds such as cormorants are included in this category.

Stupefying methods

Stupefying methods include the use of poison or under water explosives to paralyse the fish. These methods are prohibited in responsible fisheries.

Grappling and wounding gear

Sharp implements such as clamps, tongs, lances, bow and arrow, harpoons and rifles are used for catching fish by wounding, grappling and killing.

Electrical fishing

Effect of pulsating electric field on fishes such as first reaction, electrotaxis (anodic attraction), electro-narcosis and electrocution are utilised in electrical fishing equipment. Effect of electric field is also made use of in other fishing systems such as trawls and hook and line to enhance fishing efficiency.

Harvesting machines

Sophisticated, modern systems like fish pumps which are used to mechanically transfer fish attracted and concentrated by light in the proximity of the vessel; mechanical dredges which make use of hydraulic jets and conveyors or suction equipment for harvesting molluscs; and fully automatic long line systems in which every step in the shooting and hauling operation including baiting and removal catch are automated, could be included in this category.

References/suggested reading

Andeev, N. N. (1962) Handbook of Fishing Gear and its Rigging, Israel Program for Scientific

Translations, Jerusalem

Bainbridge, R. 1958. The speed of swimming of fish as related to the size and to the frequency and amplitude of the tail beat. J. Exp. Biol. 35(1):109-133

Ben-Yami, M.(1994) Purse Seining Manual, FAO Fishing Manual, Fishing News Books Ltd., Farnham. 416 p

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Bjordal, A. and Lokkeborg, S. (1998) Long lining, Fishing News Books Ltd., Farnham. 208 p

Boopendranath, M.R. (2009) An overview of fishing gears and their design and construction, pp. 31-66, In: Handbook of Fishing Technology, CIFT, Cochin

Brandt, A.v. (1959) Classification of fishing gear, In: Modern fishing gear of the world (Kristjonsson, H., Ed), Fishing News Books Ltd., London: 274-296

Brandt, A.v. (1984) Fish Catching Methods of the World, Fishing News Books Ltd., London: 432 p. ISBN 0-85238-125-5

Edwin, L., Pravin, P., Madhu, V.R., Thomas, S.N., Remesan, M.P., Baiju, M.V., Ravi, R., Das, D.P.H., Boopendranath, M.R. and Meenakumari, B. (2014) Mechanised Marine Fishing Systems: India, Central Institute of Fisheries Technology, Kochi: 276 p. ISBN: 978-81-924362-8-9

FAO (1975) Catalogue of Small-scale Fishing Gear, Fishing News Books Ltd., Farnham, 191 p

FAO (1978) FAO Catalogue of Fishing Gear Designs, Fishing News Books Ltd., Farnham. 159 p

Fridman, A.L. (1986) Calculations for fishing gear designs, FAO Fishing Manual, Fishing News Books Ltd., Farnham. 264 p

Gabriel, O., Lange, K., Dahm, E. and Wendt, T. (Eds.)(2005) Von Brandt’s Fish Catching Methods of the World, 4th edn., Wiley-Blackwell: 536 p. ISBN: 0852382804

George, V.C. (1971) An Account of the Inland Fishing Gear and Methods of India, Spl. Bull. No. 1, Central Institute of Fisheries Technology, Cochin. 68 p

Hameed, M.S. and Boopendranath, M.R. (2000) Modern fishing gear technology, Daya Publishing House, Delhi. 186 p

Meenakumari, B., Boopendranath, M.R., Pravin, P., Thomas, S.N., and Edwin, L. (2009) (Eds.) Handbook of Fishing Technology, Central Institute of Fisheries Technology, Cochin. 380 p

Misund, O.A., Kolding, J. and Freon, P. (2002) Fish capture devices in industrial and artisanal fisheries and their influence on management, In: Handbook of Fish Biology and Fisheries Volume 2: Fisheries (Hart, P.J.B. and Reynolds, J.D., Eds), Blackwell publishing, UK. 13-36

Nedlec, C. (1982) Definition and classification of fishing gear categories, FAO Fish. Tech. Pap. 222, Rev.1: 51 p

Sainsbury, J.C. (1996) Commercial Fishing Methods: Introduction to Vessels and Gear, Fishing News Books, Farnham, UK. 192 p

Sambilay, V.C., Jr. (1990) Interrelationships between swimming speed, caudal fin aspect ratio and body length of fishes. Fishbyte. 8(3):16-20

SEAFDEC (1986) Fishing Gear and Methods of Southeast Asia Vol. I: Thailand, Training Department, Southeast Asian Fisheries Development Centre, Samutprakarn. 329 p

SEAFDEC (1989) Fishing Gear and Methods of Southeast Asia Vol. II: Malaysia, Training Department, Southeast Asian Fisheries Development Centre, Samutprakarn. 338 p

SEAFDEC (1995) Fishing Gear and Methods of Southeast Asia Vol. III: The Philippines, TD/RES 38, Training Department, Southeast Asian Fisheries Development Centre, Samutprakarn. 341 p

Videler, J.J. (1993) Fish Swimming, Chapman and Hall, London. 260 p

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Novel Extension Approaches for Sustainable Technology Dissemination in Fisheries A. K. Mohanty*, M. V. Sajeev, V. K. Sajesh

*E-mail: [email protected]

Trends in aquaculture and fisheries Global fisheries have made rapid strides in recent years by establishing its strong hold over increasing food supply, generating job opportunities, raising nutritional level and earning foreign exchanges. These benefits become more important when placed in the context of current challenges in food production, nutritional security, social transitions and growing climate uncertainties. Fish and fishery products are the most traded food commodities in the world accounting for 1% of world merchandise trade in value terms representing more than 9% of total agricultural exports all over world (FAO, 2014). About 38% of the global fish production enters international trade in various forms and shapes, generating an export earning of nearly US$148.1billion with a record import at US$140.6 billion during 2014. Mostly the developing countries that account for over 60% of global fish catch, which has continued to expand at an average annual rate of 8.8% (FAO, 2009 & 2012) and play a major role in the global trade of fish and fish products contributing around 50% of fishery exports in value terms and more than 60% in quantity terms supplied by them (World Bank, 2011). At the same time, demand for fish products are likely to rise as a result of rising populations that are expected to reach 9.3 billion by 2050. Developing countries have a positive trade balance due to their increasing involvement in global fisheries trade. Developing country like India may have higher proportion of population growth but its impressive economic growth over the past two decades has resulted in steady increase in per capita income in real terms that in turn increases the purchasing power of people resulting in increasing demand for food to feed & ensure nutritional security of the population. As a result of which it brought inconsistency in fish consumption pattern across the coastal, marine and hill region. It is estimated that fish production generally contributes 0.5 – 2.5 % of GDP globally (Allison 2011). In spite of that globally an estimated population of more than 1.3 billion people are in extreme poverty (2016), 795 million people (2015-16) are estimated to be in chronic hunger and an estimated one third of children in the developing world under five years of age are stunted (Conway 2012). Fish is considered as the most affordable and frequently consumed animal-source food in low income food deficit countries in sub-Saharan Africa, Latin America and Asia (World Bank,2006).It is an important source of a wide range of intrinsic micronutrients, minerals and fatty acids. It accounts for about 17 % of most affordable, easily digestible, high-quality animal protein and 6.7 % of all protein, all essential amino acids, essential fats (e.g. omega-3 fatty acids), vitamins and minerals thus contributing to a great extent to food and nutrition security in many Asian and African countries where large proportion of population are still in hunger and under nourished (Kent,1987). Besides small-sized fish species are excellent source of many essential minerals such as iodine, selenium, zinc, iron, calcium, phosphorus, potassium, and vitamins such as A, D and B. About 150 g of fish provides about 50–60 % of daily protein requirements for an adult. On an average, fish provides about 20–30 kilocalories per person per day. In addition,

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dietary diversity of the region is mainly influenced by different quantitative and qualitative attributes viz., income, price, preference, market, type and quality of products, cultural traditions, beliefs as well as various geographical, environmental, social and economic factors that influences the fish consumption pattern.

Despite the significant contributions by the sunrise sector, global debates on fisheries issues and policies appear to be dominated by concerns over environmental sustainability, overfishing and overcapacity. In this context, it is alarming to note that the sector has not received adequate attention from the social scientists to understand its various socio-economic dynamics to prove the sunrise sector as a potential driver of local and national economic development.

Major concerns in fisheries

Food security has become the prime concern with the increasing trend of population growth in a country. Over the last fifty years, the food grain production in India has increased considerably, but the advantage of this increase in food grain production has not been reflected in the per capita availability of food grains. As per estimate, the human population and food grain production in India has grown up by 2.09% and 2.36%, respectively from 1961 to 2011, whereas the annual per capita availability of food grains has come down from 171.1 kg in 1961 to a level of 169 kg in 2011 showing a decreasing trend of 1.17 %. In case of fish, Asia accounts for almost two-thirds of global fish consumption i.e. 21.4 kg per capita per year in 2011 – a level similar to Europe (22.0 kg/cap/yr) and North America (21.7 kg/cap/yr), and close to the levels of Oceania (25.1 kg/cap/yr), whereas Africa, Latin America and Near-East have lowest per-capita consumption (10.4, 9.9 and 9.3 kg/cap/yr in 2011, respectively). Although annual per capita apparent consumption of fish products has grown steadily in developing regions (from 5.2 kg in 1961 to 17.9 kg in 2011) and in Low Income Food Deficit Countries (LIFDCs) that increases from 4.4 kg in 1961 to 8.6 kg in 2011, it is still considerably lower than in developed regions (from 17.1 kg in 1961 to 23.0 kg in 2011). It is clearly evident that rising population is nullifying the effect of growth in food grain production, keeping aside several other factors which determine the access to food grains. In this context, increasing fish production to meet the challenges of nutritional security has drawn the attention of the planners and policy makers. Hence, aquaculture is considered as a promising food production sector for high quality protein food and providing livelihood to the rural populace, which needs to be more efficient and cost-effective. However, there is multitude of challenges associated with the growth of this industry.

The fishery sector is a major foreign exchange earner for any developing countries. In India, its foreign exchange earnings were estimated to increase by 16 to 20 per cent in 2005 and 26 to 42 per cent by 2015. Nearly 85 per cent of the export benefits are projected from shrimp export alone. Because of its potential and rich source of animal protein, fish demand has been rising in both the developed and developing world at more than 2.5 percent per year (Peterson and Fronc, 2007) and demand levels were raised in proportion to increase in income in highly populated countries like China and India, (Garcia and Rosenberg, 2010). In view of higher production in fisheries, producers may lose from price fall in the domestic market; where prices were estimated to fall by 15 to 20 per cent by 2005 and 27 to 54 per cent by 2015. In spite of the phenomenal success of the sector, still there are some major issues related to the economic and nutritional conditions of fisher folk in addition to some important concerns in the context of rising environmental hazards, depressing prices world over, emerging new economic challenges

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following establishment of WTO, IPR & SPS issues, compliance of several multilateral agreements, etc.

In the post- harvest front, the processing industries face multifarious problems like complicated exporting procedures, high shipping costs, cut-throat competition in the industry, changing quality standards of importing countries, irregularity in supply of raw materials, hygiene problems and non-availability of quick transportation facilities from the fishing port to the processing units, etc. As a result of which trade-driven commercial fish farming is suffered that reduces the livelihood opportunities of small scale dry fish processors, petty traders within the communities of poor fishermen.

Environmental degradation poses a challenge to the phenomenal success of the fishery sector in promoting food security and adversely creates impact on nutritional rights and livelihood status of the fishermen communities for whom fish and fishery products are critical for their health benefit and wellbeing. As per directives of international conventions like Kyoto Declaration and Code of Conduct of Responsible Fisheries, this trade-driven, resource depletion sector can be sustained through by-catch reduction and juvenile fishing ban. The benefit of this may be accrued through policy level intervention by institutions within the legal framework.

Small-scale fisheries are normally characterized by low capital input activities, low capital investments, lack of equipment and labor-intensive operations followed by traditional fishers. They also usually operate as semi-subsistence, family-based enterprises, where a share of the production is kept for self-consumption (Garcia et al., 2008). Traditional fishers dominate the marine sector and they are socially deprived, educationally weak with very high occupational rigidity. There is inequity in the distribution of yield and effort in marine fishing in case of traditional fishing communities. They are unorganized with least social security. The informal social security system in the form of sharing of earnings among the community prevailing in the traditional fishing is hardly seen in the mechanized fishing. There are also huge regional variations in productivity among them.

Technologies are the main drivers of growth. Hence, systematic technological interventions backed by appropriate policy and institutional support are vital for making the aquaculture operations sustainable and economical. Generally, the technologies and trade interventions reinforce each other which can be characterized as skill-based, cost effective, capital intensive which can bring a change in the performance of the sector. Keeping eye upon this, following strategies have been suggested for an accelerated fishery development with focus on poverty alleviation of poor fishers:

Commodity-centered approach System approach Prioritize technology on the basis of needs and problems at micro and macro levels Skill development/upgradation of the fishers Monitoring the technology demonstrations programs and assess the impacts. Innovate and strengthen institutions and policies Enhance investment and reorient policies to facilitate percolation of benefits to all sections of

the society.

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Follow ecological principles Emphasize on domestic market demand and consumers’ preferences Strengthen database and share it for a better planning and policy making in the sector.

Extension systems for sustainable development

Unlike India, the economy of developing and underdeveloped countries in sub Saharan Africa, Latin America, Asia inclusive of 22 Low Income Food Deficit Countries (LIFDCs) is predominantly agrarian economy, where agriculture inclusive of fisheries provides employment and livelihood to majority of the rural households, but the condition of both farmers/fishers and farming is in alarming state.

Hence, there is an urgent need to reform that agriculture allied sectors in holistic, scientific and systematic approach to meet the recent challenges due to climate change and global competitiveness so as to achieve sustainable production and growth under different agro-climatic conditions.

As per the report of world commission on Environment and Development (1987), sustainable development meets the needs of the present generation without compromising the ability of future generation to meet their requirements. The FAO committee on Fisheries (1991) defines sustainable development more elaborately as the management and conservation of national resource base and the orientation of technological and institutional intervention to ensure the attainment of human needs for present and future generation including fulfilment of social and economic demands and conserving the natural resource base. In response to that FAO developed a code of conduct for Responsible Fisheries (FAO, 1995) that provides principles and guidelines for ensuring sustainable exploitation of marine resources. Sustainable fisheries can be possible through responsible fishery, which envisages rational fishery management that address a range of issues dealing with resource status, environmental health, post-harvest technology, trade and export, socio-economic benefits, legal and administrative support. Sustainable agricultural systems must be resource-conserving, socially supportive, commercially competitive, and environmentally sound. Hence, the agriculture research system must place emphasis on generation of resource conservation technology (RCT) along with strong forward-backward linkage between research-extension system. It involves design and management procedures that work with natural processes to conserve all resources, promote ecosystem resilience and self-regulation, minimize waste and environmental damage, while maintaining or improving farm productivity and profitability (MacRae et al., 1990).

The role of extension in fisheries cannot be ignored. Strong extension system is the key to bring the desired changes to meet the present day challenges related to sustainable fisheries. Basically, the end product of the fisheries extension system is to work with fisheries within an agro-climate and economic environment by providing suitable technologies to enrich knowledge and upgrade skills to improve better handling of natural fish resources and applying the cutting-edge technologies to achieve desired production level. Extension system plays a pivotal role in empowering fishers and other stakeholders to make fish farming more participatory, demand-driven, knowledge intensive and skill supportive for disseminating most appropriate technical, management and marketing skill to improve profitability in fisheries that can overcome the emerging challenges and concern, thus developing a synergistic pathway for enhancing

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productivity along with quality produce in order to sustain production base and ensure ecological and livelihood security. The extension system needs to disseminate a broad array of information starting from farm to fork in an integrated manner for safe delivery from field to the consumer considering all the aspects of conservation and production technologies, post-harvest management, processing and value addition. Such knowledge based decision should be incorporated in reshaping of extension approaches. In present scenario, the extension system envisages a transformation from technology driven to market driven extension, where fishers would give emphasis on commercialization of fish and fish based products, maintenance of quality, fulfilling consumers’ demands, etc., in the program planning process for the effectiveness of any extension programme.

Further, with the advent of global competitiveness and market liberalization, our prevailing extension system has to be strengthened with innovative extension approaches to tackle the recent challenges in fisheries viz., climate change, weather aberrations, dwindling resources and quality and safety of products; so that fishers can adjust their production portfolio keeping eye upon the emerging trends in food consumerism in domestic as well as global markets. Grooming fishers with proper information support for taking right decision related to fish production essentially requires a strong network of extension systems, supported with government initiatives and strong linkage among extension scientists and functionaries working for fishery sector development. This would ensure the livelihood security of millions of fisher communities by improving the quality production and creating better job opportunities, which intends to bring out planned changes to meet the needs of the present generation without compromising the future generation’s requirements. Innovative extension approaches for technology dissemination in fisheries

Earlier in developing countries, the extension personnel were involved in diffusion of farm technologies generated by public research organizations, mostly disseminated through appropriate mechanism, viz., On Farm Trials (OFT), frontline demonstrations (FLD), field visits, fishers’ meetings, media use, etc. This process had the conceptual backup from the ‘diffusion of innovation’ model. But in the last two decades, the paradigm shifts in development pivots to the enhanced concern for future generations to meet their basic needs, accordingly the nature, design and integration of fisheries technologies are drawing attention of the extension professionals and practitioners across the globe. In India, different models for transfer of technology have been tested and some robust extension approaches have been validated. Furthermore, the frontline extension system of the country has been revisited and sharpened through fishers oriented approaches for technology adaptation and dissemination. The extension system in India has been designed to move beyond technology and beyond commodity through reciprocal fishers-research-extension linkages. Fish farmers still suffer from lack of access to appropriate services like credit, inputs, market, extension, technologies etc. Keeping eye upon this, the World Development Report has focused on need to restructure and revamp agricultural extension system as a tool for realizing the growth potential of farm sector against the widening demand–supply pressures for ensuring sustainable fisheries, inclusive, pro-poor socio-economic development. Therefore, participatory technology development and participatory extension approaches emerged as a part of integration of the ‘interdependence model’ and the ‘innovation systems framework’ that offered more inclusive ways of involving the institution in technology generation, customization and diffusion. Extension approaches have to be redefined depending

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upon the components involved for sustainable growth and livelihood security of the farmers for which a conceptual framework has to be developed in response to recognizing and considering different livelihood assets viz., human, social, physical, natural and financial resources. Some of the following innovative extension approaches originating from multiple sources must be adopted on trial basis to make fisheries more lucrative and sustainable which can be replicated in the fishery sector interwoven with numerous challenges like increased production with sustained natural resources, growing market demand for processed products having entrepreneurial opportunities, protection and conservation of environment, and promoting international trade.

An analysis of national extension systems in the Asia and Pacific region by Qamar (2006) observes that agricultural extension is undergoing a major transformation as a result of failure of public extension systems perceived to be outdated in the context of globalization, decentralization, and information technology revolution. Extension systems in many developing countries are undergoing a paradigm shift to more fishers -oriented approaches based on rural innovation that emphasize the importance of interactive, integrated and multidisciplinary oriented mutual learning between formal and informal knowledge systems (Friederichsen, 2009). Asset Based Community Development (ABCD) approach

As per the traditional approach to development, poor people see themselves as people with special needs that can only be met by outside supporting agencies. But Asset Based Community Development (ABCD) approach intends for the development of community based on the principle of identifying and mobilizing individual and community ‘assets’, rather than focusing on problems and needs. It is an extension approach in which a community’s micro-assets are linked with its macro environment. It believes that communities can initiate and sustain the process of growth and development themselves by recognizing and harnessing the existing, but often unrecognized assets, and thereby promoting local economic potential to drive its development process (Rans & Green, 2005). The approach is optimistic in nature, because the focus is on ‘what is possessed by the community, rather than the problems of the community.”

The focal point in this approach is asset and not the need of the community. Assets of individuals, associations and institutions are identified after an extensive survey and assets are then matched with the need of the people to empower communities to control their futures and create tangible resources such as services, funds and infrastructures etc. (Foot and Hopkins, 2010. In fishery, ABCD approach gives greater emphasis on reducing the use of external inputs and on a high degree of social mobilization in which the assets of the poor (social, physical, financial as well as human) can be utilized to bring sustainable livelihoods in fisheries through number of different fishery related activities. Five Key Assets in ABCD

As per ABCD approach there are 5 categories of asset inventories such as individuals, associations, institutions, physical assets and connections

Individuals: Every individual has got certain assets, gifts and qualities; such individual is at the center of ABCD approach.

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Associations: Groups of people working with a common interest are critical to community mobilization. Institutions: The assets of institutions help the community capture valuable resources and establish a sense of civic responsibility. Physical Assets: Physical assets such as land, buildings, space, and funds are other assets that can be used. Connections: These are the exchange between people sharing their assets by various methods.

Rural advisory services (RAS)

Rural Advisory Services (RAS) refer to all the different activities that provide the

information and services needed and demanded by farmers and other actors in rural settings, to assist them in providing their livelihoods by developing their technical, organizational and management skills and practices (GFRAS, 2011; FAO, 2010). RAS designers and implementers must recognize the diversity of actors in extension and advisory fields (public, private, civil society); the need for extending support to farmers’ producer organizations (FPO) and rural communities (beyond technology and information sharing) including advice related to farm, organizational and business management; and explaining the role of facilitation and brokerage in rural development and value chains. In the case of aquaculture, large-, medium- and small-scale fishers need different types of RAS support. The large aquaculture farms are mostly self-reliant and need only regulatory support, while medium-sized farms need mobilization and facilitation support in addition to regulatory support. Small aquaculture farms need more education and input provision alongside facilitation (Kumaran, 2014). Timely sharing of research recommendations can address the problem of disseminating information to fishers. In this direction, innovative strategies are being formulated keeping the fishers’ needs and capacities in mind to pass on appropriate technologies by combining Internet, telecommunications, video, and print technologies that may bridge the information gap and empower fishers to make better production and marketing decisions (McLaren et al. 2009). In fishery sector, RAS helps in Providing management and business development support appropriate to the scale,

resources and capacities of each fisherman. Better understanding markets (prices, products, seasonality, standards, value addition etc.)

related to fish and fish products. Linking fishers to other stakeholders involved in provision of varied support and services. Creating platforms to facilitate interaction and sharing among the various stakeholders

including FPOs to ensure coordinated support to fishers. Exploiting information communication technologies (ICTs) to provide fishers with a range of

information related to weather, prices, extension programmes and generic information regarding fisheries.

Facilitating the formation of FPOs and also collaborate with FPOs to strengthen the demand and supply side of RAS.

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Promoting institutional and policy change to enable and support small-scale fishery. RAS encourages the formation/ organisation of groups by involving individual fishers, who

have little influence over the social, economic and political processes affecting them, but as a group/ organizations and networks they can deal with their specific challenges and make their voice heard. Such groupings can act as platforms to articulate concerns, exchange knowledge, influence policies and engage in collective action so that their agriculture remains sustainable and profitable. Effective formation of Rural Resource Centres (RRCs), Fishermen Cooperative Society, Farmers producers Organisations (FPOs) can be instrumental by galvanizing collective action in order to ensure better access to markets and to support innovation by their members in related activities (Sundaram, 2014). Model Village System of Extension (MVSE) approach

MVSE is an integrated and holistic extension approach where community participation is prioritized for suitable technological interventions in the fisheries to bring all-round development in fisheries sector in terms of socio-economic upliftment, technological empowerment, self-governance thereby enhancing the futuristic knowledge base and skills through participatory framework. MVSE emphasizes on involvement of all stakeholders in the process to converge their activities with a stake in the food value chain linking producer to consumer. Nevertheless, MVSE is an action research taken up in fishers’ farm based on the principle of leveraging the activities, investments and resources from outside agencies/ externally aided projects resulting higher productivity, ensuring food security and sustainable improvement in overall quality of life by promoting leadership, self-dependency of the community in food chain. Economically viable, ecologically compatible and socially acceptable suitable technologies are successfully intervened in a cluster approach through participatory mode by integrating the multi-disciplinary research. The cluster of villages is adopted as model village, the success of which is later replicated to other villages. The village is developed as a commodity village branding for a particular commodity in the market.

MVSE approach works on the following principles: • Promotes self -governance among the fishers • Skill improvement and leadership development among the fishing community. • Establishing linkage through pluralistic convergence of various stakeholders associated in the

sector. • Encouraging the market opportunities through commodity based village development (CBVD).

Farmers Field School (FFS) approach

The FFS extension approach is an alternative to the top down extension approach which was evolved as a method to solve complex field level issues in fisheries sectors. FFS aims to build fishers’ capacity to analyze their production systems, identify problems, test possible solutions, and eventually encourage the participant member to adopt the practices most suitable to their farming systems (FAO, 2003 c). This is a learning-by-doing approach which emphasizes group observation, discussion, dissection, modification, and promotes field-based experimentation, analysis for collective decision making followed by actions. The FFS approach is an innovative,

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participatory and interactive learning approach that emphasizes problem solving and discovery based learning. FFS also provides an opportunity to fishers to practice and evaluate sustainable resource use technologies, and adoption of new technologies by comparing with their conventional technologies developed in congruent with their own tradition, culture and resource use pattern. The goal of FFS approach is such that, after observing and comparing the results of field level experimentation fishers will eventually “own” and adopt improved practices by themselves sidelining the conventional ones without any external compulsion. Field day is being organized at the end of the season to give visibility to the entire activities to convince the non-adopters. Exchange visits with other FFS is also encouraged to learn by association and comparison A group of 20-25 fishers can form a Farm School under the guidance of a FFS facilitator. Extension workers, NGO workers, fishermen co-op members or previously trained fishers can become Farmer Field School (FFS) facilitators. The facilitators are trained by master trainers, who have expertise in the particular subject matter. FFS is a time bound activity usually covering one production cycle or a year.

It is also significant to note that irrespective of the merits of the technology, the acceptance to technologies is influenced by the extension method. Farmer Field School (FFS) model has been accepted as a good methodology because it is exclusively participatory. A special feature of this extension approach was that it reached poor and female-headed households and lower-caste households much better than the regular extension services (Tiwari et al. 2010). FFS was also found to be effective in avoiding barriers like socio- economic constraints, infrastructure problem and incompatibility of technology for the adoption of sustainable fishery practices.

The basic component of FFS is setting up of a Participatory Comparative Experiment

(PCE), commonly referred to as Participatory Technology Development (PTD), whereby the fishers put the FFS concept into practice under close monitoring and supervision by the FFS members. A PCE can be developed in the field of agriculture, livestock, fishery, forestry, agro-forestry, livelihood system and others. Principles of Farmer Field School(FFS)are as follows: -

• Field is the learning place. • Emphasizes hands on and discovery based learning. • Farmers become experts. • Integrated and learner defined curriculum. • Doing is better than learning/ seeing. • Experiences are the start of all learning. • Link to actual field situations and should be relevant to local needs and problems. • Participatory monitoring and evaluation. • Fishermen are decision makers.

Market Led Extension (MLE) approach

In order to make farming more enterprising, extension professionals need to be pro-active beyond the regular objective of maximizing the productivity of the fishers by transferring

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improved technologies rather fishers should be sensitized on various aspects of farming like culture, harvest, quality, processing and value addition, consumer’s preference and market intelligence. This will help the fishing community to realize high returns for the produce, minimize the production costs, and improve the product value and marketability that may lead to realize the concept of doubling farmers’ income (DFI). With the globalization of agriculture, emphasis on productivity and profitability to the farm enterprises has been increased and, therefore the demand- driven agriculture (and allied sectors) has led to the paradigm shift from production-led extension to market- led extension. There are many challenges in the agricultural marketing system, which can be resolved through the efforts of market- led extension models.

In this approach, fishers are viewed as ‘Fish-entrepreneurs’ who expects high returns ‘Rupee to Rupee’ from his produce by adopting a diverse baskets of package of practices suitable to local situations/ farming systems with optimum cost benefit ratio (C:B ratio) ensuring maximum share of profit by exploring the market demand. Goal of market led extension is to facilitate fishers to get better price. Market led extension focuses on harnessing the ICT tools to access market intelligence including likely price trends, demand position, current prices, market practices, communication network, etc. besides production technologies.

For farmers, as the extension system is more credible source of farm technologies, the extension personnel ought to be knowledge- and skill-oriented in relation to production and marketing of agricultural goods. Thus, revamping the extension system will have a catalytic role for ushering in farmer-led and market-led extension; which can subsequently alleviate poverty and ensure livelihood security. In the light of this, the challenge remains to motivate the extension personnel to learn the new knowledge and skills of marketing before assigning them marketing extension jobs to establish their credibility and facilitate significant profits for the fishing community. SWOT analysis of the market, Organization of Farmers’ Interest Groups (FIGs), capacity development, establishing linkage and synergy, harnessing ICTs, digital marketing etc are the competencies required by the extension personnel in order to effectively implement market led extension. Digital Extension approach

Extension reforms brought a transformation in fishery extension system through

introduction of Information and Communication Technologies (ICTs). The ICT-enabled extension system referred to as Digital Extension has the potential for enabling the empowerment of fishing communities by improving their access to information and sharing knowledge with innovative e-agriculture initiatives (Saravanan, 2010a).

With the phenomenal growth in information and communication technology, use of IT application in agriculture will bring remarkable change in the attitude and knowledge level of user. Basic requirement is to provide most appropriate information in such a capsule that can be easily understood and used by them. This approach will strengthen the extension system for better dissemination of technology. As a case study the contribution of Digital Green, a NGO that uses an innovative digital platform for community engagement to improve lives of rural communities across South Asia and Sub-Saharan Africa is remarkable. Digital Green associate with local public, private and civil society organizations to share knowledge on improved farmers

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practices, livelihoods, health, and nutrition, using locally produced videos and human mediated dissemination. As per the study, the Digital Green project (participatory digital video for agricultural extension) increased the adoption of certain farm practices seven times higher compared to traditional extension services and the approach was found to be 10 times more cost-effective per dollar spent. Hence, along with ICT-based advisory services, input supply and technology testing need to be integrated for greater impact and content aggregation from different sources require to be sorted in granular format and customized in local language for rapid adoption of technologies (Balaji et al., 2007&Glendenning and Ficarelli, 2011).

The effectiveness of this innovative extension approach depends on capacity building, people’s participation along with government initiative to provide strong infrastructure to be worked with the cutting edge technologies. The farmer friendly technology dissemination process needs to be handled with careful planning by the incorporation of information communication technology. The use of ICT application can enhance opportunities to touch the remote farmers to live in close proximity of the scientific input. The computer based web portals namely aAQUA, KISSAN Kerala, TNAU AGRITECH Portal, AGRISNET, DACNET, e-Krishi, ASHA, India Development Gateway (InDG) portal, Rice Knowledge Management Portal (RKMP), Agropedia, KIRAN, AGMARKNET, ITC-e-Choupal, Indiancommodities.com, Mahindra Kisan Mitra, IFFCO Agri-Portal, Agrowatch Portal, iKissan, etc. along with some mobile based Apps like mKRISHI® Fisheries, riceXpert, Pusa Krishi, Krishikosh, m4agriNEI CIFT Lab Test, CIFTraining etc. launched in India are some of the successful digital intervention for technology dissemination.

The use of internet, mobile and video- conferencing assists the IT enabled farmers to utilize the facilities for their favors for which the most suitable permanent infrastructure is the basic requirement. Strong linkages need to be established between direct ICT interventions and it should be part of the national level program on holistic agricultural development. Disruptive Extension approach

Recently, a new extension approach christened as ‘disruptive extension’ comes into limelight which is considered as an innovative extension approach that creates a new paradigm of extension that eventually disrupts an existing approach followed by extension professionals in the field of agriculture and allied sectors. It is an entrepreneurial oriented sustainable extension system that can able to transform every link in the food chain, from farm to fork. It is a cost-recovery extension approach the fulcrum of which lies between resource exploitation on one side and resource conservation on another side that influence the livelihood security and technology sustainability for small scale farm holders. It deals with the following principles:

• Importance of good governance in agriculture (and allied fields) that considers the

resource rights of the farmers. • Emphasis on growing interest among the stakeholders by explicit analysis of field level

issues for technology adoption. • Potential to resolve the social conflicts for equal access to community resources through

Memorandum of Understanding (MOU). • Based on cost recovery mechanism.

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• Ensure commitment to optimum resource management and maximum economic benefit to improve food security.

• Provision of community based social insurance. • Maintaining the sustenance of the technology supports through custom hiring approach. • Focus on pluralistic convergence of different partners to build a network of linkage with

various entities around the farm households. • Encouraging the farmers-scientist interaction for technology development, assessment

and application through Farmers’ FIRST approach.

Global agriculture embraces diverse actors in its endeavour to feed about 10 billion people in the planet by the end of 2050. The small, marginal & landless farmers are extremely vital for food security due to shrinking of resource day by day. The contribution of women fishers also cannot be ignored particularly in on-farm operations, harvesting, post-harvest management, processing etc., especially in fishery and animal husbandry sector. Hence, in today’s scenario innovation in agriculture extension is the key to address the growing challenges, which need to be validated, integrated and scaled up and further recommended for large scale implementation by the policy makers. The innovative extension approach should be based on capacity building, skill development, people’s participation along with government initiative to provide policy support to be worked with the cutting-edge technologies. Much effort has been initiated in going beyond the farm and the fishers and focus on beyond the technology to a wider innovation system. References/suggested reading Aiyar, Swaminathan, S. and Rajghatt, C. (2006) Delhi. Special report on ‘End of Poverty?’ Sunday Times of

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Subasinghe, R., Ahmad, I., Kassam, L., Krishnan, S., Nyandat, B., Padiyar, A., Phillips, M., Reantaso, M., Miao, W. & Yamamoto, K. 2012. Protecting small-scale farmers: a reality within a globalized economy? In: Farming the Waters for People and Food. Proceedings of the Global Conference on Aquaculture (R.P. Subasinghe, J.R. Arthur, D.M. Bartley, S.S. De Silva, M. Halwart, N. Hishamunda, C.V. Mohan & P. Sorgeloos, eds. 2010, Phuket, Thailand. 22–25 September 2010. pp. 705–717. FAO, Rome and NACA, Bangkok

Susan Singh-Renton (2016) Introduction to the Sustainable Development Concept in Fisheries

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Waite, R, Beveridge, M C M, Brummett, R, Castine, S, Chaiyawannakarn, N, Kaushik, S, Mungkung, R, Nawapakpilai, S & Phillips, M. (2014) Improving Productivity and Environmental Performance of Aquaculture. Installment 5, Creating a Sustainable Food Future. Washington D C, World Resources Institute. pp. 60. http://bit.ly/1hinFaL.

Walsh B (July 7, 2011) The end of the line. Time, pp 28–36

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World Bank (2006) Aquaculture: Changing the Face of the Waters: Meeting the Promise and Challenge of Sustainable Aquaculture. World Bank, Washington, DC

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Small Scale Fisheries Guidelines from the resource and energy conservation perspective

Nikita Gopal

ICAR-Central Institute of Fisheries Technology, Kochi

E-mail: [email protected] Small Scale Fisheries Guidelines - Introduction

About 75% of the earth’s surface is water, which holds resources on which depends the livelihood of millions – that of our fishers and their families. FAO defines fishing as ‘the capture of aquatic organisms in marine, coastal and inland areas’ and estimates that 820 million people depend on this, along with aquaculture, for food, nutrition and income. FAO (2014) from the technology point of view defines small-scale fisheries as ‘tends to imply the use of a relatively small size gear and vessel. The term has sometimes the added connotation of low levels of technology and capital investment per fisher although that may not always be the case’.

However small scale fisheries generally connotes traditional fisheries which FAO (2013) defines as that ‘involving fishing households (as opposed to commercial companies), using relatively small amount of capital and energy, relatively small fishing vessels (if any), making short fishing trips, close to shore, mainly for local consumption’.

The traditional fishers were generally considered to be resource poor, with primitive

implements or low levels of technology and the fishing activity undertaken for sustaining nutrition and incomes of fisher households, and so are small-scale. Small scale fisheries is also contextual and depends on the countries and cultures that they belong to and so may take many different forms (Staples e. al., 2004). It not only includes harvest of fish, but also includes post harvest activities, marketing, and ancillary activities. These are rooted in t It is estimated that about 90 percent of all people directly dependent on capture fisheries work in the small-scale fisheries sector and is thus a major contributor to employment, income, household sustainability and nutritional security. And about half of these workers are women.

While the arguments on what exactly what should be the definition continues, a significant happening was the development of a first ever international instrument exclusively for small scale fisheries, the Voluntary Guidelines for Securing Sustainable Small-Scale Fisheries in the Context of Food Security and Poverty Eradication or VGSSF or simply the SSF Guidelines in 2014 (http://www.fao.org/3/a-i4356en.pdf). The guidelines is dedicated to Chandrika Sharma, ’who worked tirelessly for the betterment of the lives of fish workers all over the world and who contributed invaluably to the formulation of these Guidelines’. The guidelines were developed through a participatory and consultative process involving all stakeholders and took into consideration all relevant international instruments including the Technical Guidelines for Responsible Fisheries No. 10 “Increasing the Contribution of Small-Scale Fisheries to Poverty Alleviation and Food Security”. https://igssf.icsf.net/images/SSF%20India%20workshop/COPYRIGHT/ICSF%20english.pdf.

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“Small-scale fisheries can be broadly characterized as a dynamic and evolving sub-sector of fisheries employing labour-intensive harvesting, processing and distribution technologies to exploit marine and inland water fishery resources. The activities of this sub-sector, conducted full-time or part-time, or just seasonally, are often targeted on supplying fish and fishery products to local and domestic markets, and for subsistence consumption. …... While typically men are engaged in fishing and women in fish processing and marketing, women are also known to engage in near shore harvesting activities and men are known to engage in fish marketing and distribution. Other ancillary activities such as net-making, boat-building, engine repair and maintenance, etc. can provide additional fishery-related employment and income opportunities in marine and inland fishing communities. Small-scale fisheries operate at widely differing organizational levels ranging from self-employed single operators through informal micro-enterprises to formal sector businesses. This sub-sector, therefore, is not homogenous within and across countries and regions and attention to this fact is warranted when formulating strategies and policies for enhancing its contribution to food security and poverty alleviation.” http://www.fao.org/3/ae534e/ae534e02.htm

The guidelines recognizes full-time, part time and seasonal fishers, for providing for their households and communities as well as working for commercial fishing and processing, and are basically rooted in local communities, Thus in the Indian (and other countries/ regions) context the small scale fishers would mean those who belong to traditional fishing communities along the coast and on the mainland along inland water bodies, where the men are engaged in harvest and women in other activities like processing, marketing and gleaning from inshore waters. They are also the fishers who are becoming increasingly marginalized due to the rapid changes taking place in the sector making them highly vulnerable. The SSF guidelines are specifically in the context of food security and poverty eradication. The access of fishers to the resources is thus of prime importance as only this will ensure that the tenets are secured. Small scale fishrs are characterized by low incomes, poor access to markets and other social service, lack of alternative livelihoods, adverse impacts of climate change and low adaptive capabilities etc.. Small Scale Fisheries Guidelines – Objectives, Principles and provisions

The objectives of the guidelines are ‘to ensure that small scale fisheries will among others enhance global food security; to promote its contribution to the economic and social future of the planet; to contribute to improve the socioeconomic situation of fish workers; and to achieve sustainable use of fishery resources’. And these objectives should be achieved ‘through the promotion of a human rights-based approach, by empowering small-scale fishing communities, including both men and women’. Small scale fishers must be able ‘to participate in decision-making processes, and to assume responsibilities for sustainable use of fishery resources, and placing emphasis on the needs of developing countries and for the benefit of vulnerable and marginalized groups’.

Acknowledging the diversity of the small scale fisheries, the scope is a voluntary guideline with a global scope with a focus on developing countries; covering all fishery-related activities in the marine and inland aquatic waters. The Guidelines should be interpreted and applied in accordance with national legal systems and institutions.

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The guiding principles of the SSF guidelines are the following:

1. human rights and dignity

2. respect of cultures

3. non-discrimination

4. gender equality and equity

5. equity and equality

6. consultation and participation

7. rule of law

8. transparency

9. accountability

10. economic, social and environmental sustainability

11. holistic and integrated approaches

12. social responsibility

13. feasibility and social and economic viability

The specifics include Governance of Tenure in Small-Scale Fisheries and Resource

Management, the proposition of which is that small scale fishers need to have secure tenure rights to the resources, recognising the need for responsible and sustainable fisheries. This could include granting preferential access to resources, resolution of disputes over tenure rights, effective remedial measures, including during natural and man made disasters which are increasingly affecting the coasts. It also mentions that ‘all discrimination against women in tenure practices should be eliminated’.

Under Sustainable Resource Management ‘measures should be implemented for long-term conservation and sustainable use of fisheries resources and due recognition given to the requirements and opportunities of small-scale fsheries’. Small-scale fisheries should also be in tune to the efforts towards sustainable resource management, which the State has to proactively support, including creating a proper monitoring, control and surveillance (MCS) systems applicable and suitable for small-scale fisheries, which the SSF should support. Co-management should be promoted not only in harvest but in pre- and post-harvest activities. ‘States should involve the communities in the design, planning and implementation of management measures, ensuring equitable participation of women and other vulnerable groups’.

In the section on Social Development, Employment and Decent Work , investment of States in health, education, literacy, digital inclusion and other technical skills is emphasized along with adequate social-security schemes for all workers along the value chain. Savings, credit and insurance, with emphasis on inclusion and access of women to these services is important. States should promote decent work for all and recognize the right of small scale fishers to an adequate standard of living. Migration and issues related to the same should be addressed, safety and occupational health and children’s well being and education should be ensured. Value Chains, Post-Harvest and Trade is another area covered by the SSFG. It recognizes the central role played by post-harvest activities in small scale fisheries, with women playing a

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Part 2; Section 5.14 All parties should recognize that rights and responsibilities come together; tenure rights are balanced by duties, and support the long-term conservation and sustainable use of resources and the maintenance of the ecological foundation for food production. Small-scale fisheries should utilize fishing practices that minimize harm to the aquatic environment and associated species and support the sustainability of the resource.

crucial role. Appropriate investments in infrastructure, organization and capacity building are central to this. Traditional forms of association should also be recognized. Trade should not adversely affect small scale fishers and States should promote equitable and non-discriminatory trade and access to timely and accurate market and trade information for stakeholders in the small-scale fisheries value chain should be enabled by the State.

SSFG is the first ever international fisheries instrument to talk of gender equality. It calls for gender mainstreaming in all development strategies. ‘Specific measures to address discrimination against women should be adopted’. Mechanisms must be evolved to assess the impact of legislation, policies and actions for improving women’s status and achieving gender equality. Better technologies of importance appropriate to women’s work should be developed.

Recognizing that climate change and disasters are happening and will be a major challenge, planning for adaptation, mitigation and aid, is included provided. Accountability fixing in case of man-made disasters in highlighted.

Part 3 of the SSFG deals with Ensuring an enabling environment and supporting implementation. Policy coherence , Institutional Co-Ordination and Collaboration is emphasized and measures to ensure the harmonization of policies that affect the health of marine and inland water bodies and ecosystems done. States should also promote local governance structures that contribute to effective management of small-scale fisheries. Information, Research and Communication should be used for ensuring transparency, prevent corruption and hold decision makers accountable. Platforms and networks at all levels must be used to promote the flow and exchange of information. Research in small scale fisheries must be undertaken to generate data that is necessary for policy making. Capacity Development is a major point so that small scale fishers can participate in decision-making and benefit from market opportunities. Knowledge and skills should be developed to support sustainable development and successful co-management arrangements.

States and all other parties are encouraged to implement the SSF Guidelines with support from United Nations and its specialized Agencies. The importance of monitoring systems should be recognized. Legitimate representatives of small-scale fshing communities should be involved both in the development and application of implementation strategies for the Guidelines and in their monitoring. Small Scale Fisheries Guidelines – Indian Perspective vis-à-vis resource and energy conservation

Responsible fisheries and sustainable development is a major focus (Part 2, Section 5) of the SSFG, under which Governance of Tenure in Small-Scale Fisheries and Resource Management and Sustainable Resource Management are sub-sections. The main emphasis is resource conservation, through sustainable resource management. Long-term conservation is stressed with due recognition to small scale fisheries is stressed. There is need for involving small-scale fishing communities,

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including women, vulnerable and marginalized groups, in the design, planning and implementation of management measures, including protected areas. Co-management and dispute settlement through participatory approaches are given importance.

Fishing communities in India exhibit a lot of diversity with respect to caste and community groupings, and they have distinct social structures. These can govern fishing and non-fishing activities and can include conflict resolution and resource use regulation. According to the CMFRI Census 2010, there are 3,288 marine fishing villages and 1,511 marine fish landing centres in 9 maritime states and 2 union territories. The total marine fisher population was about 4 million comprising in 864,550 families. Nearly 61% of the fishermen families were under BPL category. About 38% marine fishers were engaged in active fishing with 85% of them having full time engagement. About 63.6% of the fishers were engaged in fishing and allied activities.

In the context of the SSF guidelines, in India mainly the artisanal and traditional fishing sectors fall under the category of small scale fishers. As mentioned above, there is wide diversity in methods of fishing, crafts and gear used and in the people involved in fishing. The craft and gear are relatively smaller in size and less capital intensive (though we have examples of capital intensive craft-gear combination as well, like the inboard ring seiners). The traditional fishers have a deep understanding of the waters where they fish in and still follow the wind, currents and use the colour of the waters to identify fish shoals and fishing grounds. Much of the fishing is carried out in near shore waters. Marketing is locally governed, though with increasing sizes of certain types of crafts the first level of marketing has shifted to harbours. The common feature, however, is that the communities are disadvantaged and resource poor.

Implementation of the guidelines should be preceded by raising awareness on the guidelines. There are measures already in place in legislation protecting the rights of traditional fishers. For instance the Kerala Marine Fishing Regulation Act specifically prohibits other fishing vessels from passing through areas where traditional fishers have their nets or tackles. Both The Orissa Marine Fishing Regulation Act, 1981and The Gujarat Fisheries Act 2003 mention under Regulation of Fishing in Specified Areas, ‘the need to protect the interest of different sections of persons engaged in fishing, particularly of those engaged in fishing by use of traditional fishing craft such as catamaran, country craft or canoes’. However, there is increasing conflict between traditional and other fisheries which needs to be managed, mainly because the small scale sector is vulnerable and sometimes voiceless. That decisions in fisheries must be based on participatory principle taking into account all sectors is an underlying message in the guideline.

From the point of view of resource and energy conservation the artisanal sector has a clear advantage in it that their crafts and gear are not energy intensive (with a few exceptions) and the running costs and fuel expenses are lower than that of mechanized crafts. The traditional artisanal fisheries reliance on exogenous energy is relatively smaller and there are still instances of using wind energy (using sails) or purely animate energy for fishing (like in catamarans). Motorization of traditional crafts has led to using fossil fuels for propulsion. The number and capacities of engines used is also increasing with increasing craft and gear sizes which needs to be regulated as this increase has made fishing uneconomical (Edwin and Hridayanathan, 1997).

Traditional fishery that uses several passive gears like hook and line are resource friendly. At the other end of the spectrum is the wanton destructive practices like like poisoning and dynamiting, which are however slowly waning with strict regulatory measures in place in

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several Marine Fisheries Regulation Acts. Similarly the use of small meshes and increase in effort has almost wiped out the hilsa fishery in West Bengal with government forced to bring in regulations (http://www.uniindia.com/...). The weakening of traditional systems of governance has been one reason for the rise in such practices. There were systems like the Oor panchayats of Tamil Nadu (Thamizoli and Prabhakar, 2009) and Kadakkodi of Kerala (Paul, 2005) which governed the social, cultural and economic activities of fishing communities. Co-management initiatives like that of an eco-system based approach in the yellow clam fishery of Ashtamudi (Mohamed and Malayileth, 2013), the Cherai Poyil system of co-management of lagoon fisheries in Kerala (Thomson and Gray, 2009), and the already existing traditional measures like the prawn fishing in Pulicat lake (http://cmsdata.iucn.org/..) etc. are examples where resource conservation has been a central focus along with improving the livelihoods of the fishers involved in the fishery. This has been more effective in the small scale fisheries sector, mainly as a response to fall in catches and increase in operational expenses. This is particularly important in small scale sector as by its very nature the fishing is closely linked to household food and nutritional security, though in several states artisanal fishing has traditionally met the demands of consumers in inland areas (Kocherry and Achary, 1989). Conclusion

Recognizing that the small scale fishers are a vulnerable group and considering that the small scale fisheries are largely resource and energy friendly, the SSF guidelines are a first step in bringing to the fore the importance of small scale fishing communities and the role it plays in ensuring livelihoods. Sustainability, gender equality, a human rights based approach and several other fundamental principles are rooted in the SSF Guidelines. Capacity building at grassroots level on the provisions in the guidelines, followed by participatory policy evolution is essential to make the SSFG effective. References/suggested reading

Edwin, L and Hridayanathan, C. (1997) Energy efficiency in the ring seine fishery of south Kerala coast, Indian J. Fish. 44(4): 387-392

FAO (2013) Terminology(A7.4b)/CPAM, FAO, September 2013; Rio 2012 Issues Briefs, United Nations

Conference on Sustainable Development (Rio+20); (http://www.uncsd2012.org/rio20/index.html)

FAO Fisheries and Aquaculture Department, FAO, 2014; Terminology (A9.1FI)/CPAM, FAO, 2014

http://cmsdata.iucn.org/downloads/india_feedback_from__workshop_i.pdf http://www.fao.org/3/ae534e/ae534e02.htm http://www.fao.org/3/a-i4356en.pdf http://www.uniindia.com/bengal-govt-imposes-ban-on-catching-young-

hilsa/states/news/1317400.html https://igssf.icsf.net/images/SSF%20India%20workshop/COPYRIGHT/ICSF%20english.pdf. https://www.fisheries.kerala.gov.in/sites/default/files/inline-

files/KERALA%20FISHERMEN%20MARINE%20FISHING%20ACT.pdf

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Kocherry, T. and Achary, T., 1989, Fishing for Resources: Indian Fisheries in Danger, Cultural Survival

Quarterly Magazine, June 1989_Available at https://www.culturalsurvival.org/publications/cultural-survival-quarterly/fishing-resources-indian-fisheries-danger

Mohamed, K., S., and Malayilethu, V., 2013, Towards an ecosystem approach to fisheries management in India - case study of the Ashtamudi Lake yellow-foot clam fishery, Regional Symposium on Ecosystem Approaches to Marine Fisheries & Biodiversity, October 27-30, 2013, Kochi. pp 27-30

Paul, A. (2005) Rise, fall, and persistence in Kadakkodi: an enquiry into the evolution of a community institution for fishery management in Kerala, India, Environment and Development Economics, Volume 10, Issue 1, February 2005 , pp. 33-51, DOI: https://doi.org/10.1017/S1355770X04001767, Published online by Cambridge University Press: 17 January 2005

Staples, D., Satia, B. and Gardiner, P.R. (2004) A research agenda for small-scale fisheries Asia-Pacific Fishery Commission, Rap Publication 2004/21, Fipl/C10009 (En), Food And Agriculture Organization Of The United Nations, Regional Office For Asia And The Pacific, Bangkok, 2004

Thamizoli, P., and Prabhakar, P.I. (2009) Traditional Governance System of Fishing Communities in Tamil Nadu, India: Internal Mandate, Interfacing and Integrating Development. In: Communities in Coastal Zone Management, Edition: First, Chapter: Traditional Governance System of Fishing Communities in Tamil Nadu, India: Internal Mandate, Interfacing and Integrating Development, Publisher: Research Publishing Services, Singapore (Ed: Rajib Shaw)

Thomson, K. and Gray, T. (2009) From community-based to co-management: Improvement or deterioration in fisheries governance in the Cherai Poyil fishery in the Cochin Estuary, Kerala, India?, Marine Policy, Volume 33, Issue 4, July 2009. pp 537-543

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Energy Efficient Fishing Vessels and use of Alternate Energy for Fishing

M.V.Baiju ICAR-Central Institute of Fisheries Technology, Kochi


The annual fuel consumption by the mechanized and motorized fishing fleet of India has

been stimated at 1220 million litres which formed about 1% of the total fossil fuel consumption in the country in 2000 releasing an estimated 3.17 million tonnes of CO2 in to the atmosphere at an average rate of 1.13 tonnes of CO2 per tonne of live weight of marine fish landed. The increasing fuel cost causes substantial loss to the fishery industry eating away fisherman’s income. Thus the need of Green fishing systems with energy efficient hull form and utilization of renewable and non-polluting energy started spreading around the globe.

In the context of the harmful impacts of burning fossil fuel and the cost involved, the need

for fuel efficient fishing vessels in the commercial sector is gaining importance. ICAR-CIFT is conducting extensive research in this field for the past several years. Combination or multipurpose fishing is one of the methods to save fuel. Improving hull efficiency is another step. The hull is the most important part of a fishing vessel as it has direct contact with water. The shape of hull determines the amount of drag pull and how the vessel will respond/perform at different speeds and in different water conditions. An efficient hull has less drag and uses less fuel, Use of light materials for the construction of fishing vessel is also experimented by CIFT. The following diagram explains the energy distribution in a fishing vessel.

The main engine delivers power to the propeller through a reduction gear box. The energy available from the propeller shaft (27%) rotates the propeller, to overcome skin friction (18%), wake resistance, propeller wash against the hull (17%) and air resistance (3%). Advanced designs in fishing vessel hull and fuel innovations reduced the fuel consumption significantly.

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Factors affecting hull resistance

Appendage resistance contributes to about 1 – 3 percent of the total resistance for a vessel in calm water condition. Roughly about half the appendage resistance is attributed by the bilge keels and the other half to the rudder. Fig.1 shows the bilge keel and Fig 2 shows the rudder which are projecting outside the hull.

Fig.1. Bilge keel fitted to the under water hull

Fig. 2. Rudder Two aspects of hull design that directly affect the fuel efficiency of a fishing vessel are

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(i) The underwater hull form at the stern, in particular the area around and forward of

the propeller aperture, affects operational efficiency of the propeller in the wake.

(ii) The overall hull form, in particular the slenderness of the hull, affects the vessel's resistance and, therefore, its power requirement and fuel consumption.

The bare hull of a fishing vessel is considered to have three hydrodynamic resistance components in calm water

(1) Skin friction resistance: The effect of viscous friction between the water and the ship's hull.

(2) Viscous pressure resistance: The result of the distribution of pressure around the hull that is related to the thickness of the boundary layer and wake (separated flow) in the flow pattern. It is Often called form drag. (3) Wave making resistance: Is caused by water pressure on the hull, and is associated with generating a pattern of waves on the water surface as vessel moves along. The resistance is due to the energy required to create these waves. Fig. 3 shows the wave making pattern of a vessel and Fig.4- shows the components of resistance of a vessel at sea.

Fig. 3. Wave making pattern

At low speeds, the waves made by a vessel are very small and the resistance is almost wholly viscous. As speed increases the viscous resistance increases moderately with speed. However, the wave making resistance increases greatly with speed.

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Fig. 4. Components of resistance of a vessel at sea

The most important method for reducing fuel consumption is to travel to the fishing grounds at reduced speed. Excessive weed or barnacles that grows on the hull will result in increase of friction up to by 50%.

The drag due to appendages such as rudder, bilge keels, transducer mounts and cooling water pipes etc. can add up to 20% of the total hull drag. Where the design of appendages focuses on simplicity, low capital cost and robustness, excessive drag may exist. For a typical 15m vessel travelling at 10 knots, an aero foil rudder consumes nearly 6kW (4%) less engine power than a flat plate rudder. If the rudder is turned to 10 degrees, the aero foil rudder consumes about 4kW (3%) less than the flat plate rudder. Other parameters such as the selection of main engine, reduction gear, propeller, introduction of bulbous bow to the hull, and use of alternate source of power for auxiliary purposes also results in improving the efficiency. Use of nozzle propeller increases the thrust by 5 to 10 % in a trawler.

Methods to improve the efficiency of fishing vessel hull form Hull for optimization: To minimise hull resistance we can optimize the fore body and aft body optimization. Minimize the appendage resistance: The conventional method of hull form analysis is by conducting a model test in a towing tank. Appendages such as bilge keel should be avoided, if not possible the shape should be model tested in a towing tank or analysed in CFD so that the resistance will be minimum. The advantages of CFD analysis are the saving in cost compared to model testing. Also the CFD analysis is very much faster compared to model testing. Refining a hull model in CFD is easier than in a model testing.

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Fig. 5. CFD model of a fishing vesel

Proper selection of speed of vessel: The economical speed range for fishing vessels is decided using the Froude number which falls between 1.0 to 1.3 for fishing vessels. Higher values will lead to higher consumption of fuel due to increased resistance. As shown in the Fig. 6, the resistance increses exponentially with increase in speed. So choosing higher speeds will reduce the efficiency of the vessel.

Fig. 6. Resistance versus speed.

Design of efficient propulsion system: The power generated by the main engine is transmitted to the propeller through a reverse reduction gear box and shaft.There will be frictional losses in this process. So an efficient combination of propeller and shaft system will improve the efficiency

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Minimising the weight of the total fishing vessel: This can be achieved by selecting light materails for construction of different parts of the vessel. A vessel with whel house and cabin built in FRP saves around 10 % weight. This will naturally lead to lower resistance. While selecting the main engine, gear box, winch, etc care is to be given for ligher brands. Use of nozzle for trawlers: The increase in thrust of trawler by fitting a nozzle around the propeller is estimates as 5 % approximately.

Bulbous bow: A bulbous bow can yield a significant reduction in drag (> 10%) on displacement craft moving at Froude number greater than 0.3. For a 15m vessel this corresponds to >7 knots.

Excessive form drag often occurs if a vessel with a transom stern is trimmed by the stern. Proper trim adjustment is important, even extra weight (ballast) in the bow to achieve level trim might

reduce total drag.

Fig.7. Bulbous bow in the forward of the hull

Solar power for light and fan: The application of solar power for cabin lights, navigational light and fan can save on the fuel consumption. Alternate energy for fishing vessels Solar powered boats: Solar powered boats get their energy from the sun. Using electric motors and storage batteries charged by solar panels and photovoltaic cells, solar powered boats can significantly eliminate their use of fossil fuels. Solar boats are uniquely suited to transform light energy into movement. ICAR-CIFT has developed the designs of solar powered fishing vessels for fishing in the inland, back waters and rivers. First vessel 3.63 m Loa FRP solar boat can run continuously for 4 hours in the day time which is highly useful for the fishers. This is used by the tribal fishers at Malampuzha reservoir. The second boat 8.0 m Loa solar boat can run for 4 hours continuously in the day time and is in use at Fish farm, MATSYAFED, Njarakkal. Also solar power can be very effectively utilized to power the light, fan, navigational equipment and other small power applications onboard mechanized fishing vessels. This will reduce the quantity of diesel burned and will in turn reduce the GHG emission. The main advantages are:

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1. No fuel cost 2. No pollution from the burning of fuel 3. Less carbon footprint 4. Clean FRP surface 5. Wider boat and low rolling during fishing 6. More deck area 7. Suitable for shallow waters 8. No sound pollution 9. Canopy for protection from rain and sun.

Fig. 8. ICAR-CIFT Sunboat-I

Fig.9. ICAR-CIFT Sunboat-II LNG powered fishing vessels The use of liquefied natural gas (LNG) as ship fuel has recently gained more attention in Europe, but also in Asia and the USA. A marine LNG engine is a dual fuel engine that uses natural gas and bunker fuel to convert chemical energy in to mechanical energy. Due to the burning properties of

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natural gas which is cleaner, the use of natural gas in ship propulsion plants is becoming an option for companies in order to comply with IMO and MARPOL environmental regulations. The natural gas is stored in liquid state (LNG) and the boil-off gas is routed to and burned in dual fuel engines. There are three benefits which, taken together, make LNG as ship fuel one of the most promising new technologies for shipping. The use of LNG as ship fuel will reduce sulphur oxide (SOx) emissions by 90- 95%. This reduction level will also be mandated within the so- called Emission Control Areas (ECAs) by 2015. A similar reduction will be enforced for worldwide shipping by 2020. „ A lower carbon content of LNG compared to traditional ship fuels enables a 20-25% reduction of carbon dioxide (CO2 ) emissions. Any slip of methane during bunkering or usage needs to be avoided to maintain this advantage. LNG is expected to be less costly than marine gas oil (MGO) which will be required to be used within the ECAs if no other technical measures are implemented to reduce the Sox emissions. Current low LNG prices in Europe and the USA suggest that a price – based on energy content – comparable to heavy fuel oil (HFO) seems possible, even when taking into account the small scale distribution of the LNG. ICAR-CIFT has already initiated research actions in this field along with Petronet Kochi LNG terminal.

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Basics of Designing of Fishing Vessels

M. V. Baiju Fishing Technology, Central Institute of Fisheries Technology, Kochi


Introduction

The design of a fishing vessel is done to meet the requirement of the fisherman. The type of fishing, number of days for fishing, capacity of fish store and speed are very important. At the same time the vessel designed and built should be economical for the owner in terms of fuel consumption. The requirements of the owner are explained below.

Criteria of vessel design

Type of fishing and deck equipments

One of the most important criteria to be considered during the initial stages of boat design is the method of fishing. The fishing method decides the arrangements to be made in the boat. In the case of a stern trawler, the trawl winch will be placed in the aft of the wheel house. The wheel house of a stern trawler is placed in the mid ship on the main deck. The trawl gallows are to be fitted in the aft end of the main deck. The derrick needs to be placed just aft of the wheel house. This arrangement will suit the stern trawling activities. The fish hold is positioned forward of the engine room. This arrangement will balance the weight of the boat. The main engine, winch and other machinery will be placed suitably for meeting these requirements. This General Arrangement will vary for a purse seiner or tuna Long liner. A purse seiner will not have the gallows, trawl winch and derrick. Majority of the purse seiners operate the net manually. The net is spread on the forward deck and occupies complete deck space in the forward. Some of the vessels have started fitting a purse winch in the aft of the wheel house. The fish hold position is same as the trawler. The long liner will be fitted with a main line spooler on the forward deck in the port side and the line setter will be fitted in aft of the deck. The fish hold position remains in the forward. Gallows and derrick are not required for the long liners.

Material

Different materials are used for the construction of fishing vessels. The most popular materials used are steel, wood and fiber glass reinforced plastic. Aluminium, and FRP laminated plywood are also used for light vessels. Ferro cement was also used for vessel construction, but due its high weight did not become a popular choice. The selection of material depends on the size of the boat and type of fishing. Small sized beach landing boats are constructed with FRP, wood and plywood whereas larger sized deep sea going purse seiners and trawlers are built in steel.

Dimensions of the boat

This depends mainly on the capacities for fish store, fuel, fresh water and ice. The endurance is also a deciding factor of the vessel size. For boats with long endurance the storage capacity of fresh water, diesel and ice will be higher. This will increase the size and weight of the boat.

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Capacity and method of fish storage

The capacity of fish hold and storing method are important in deciding the size of the boat. Vessels with insulated fish hold and freezing facility will have large size. The generators for running the refrigeration systems are to be placed in separate space. This requires additional space.

Speed of vessel

The speed of vessel is an important parameter since this decides the engine power. High horsepower means high expenditure on fuel and the cost operation of the boat will increase. Higher horse power requires higher storage space for fuel.

Draft of the vessel

The draft which is the depth of the vessel below water level is an important factor in fixing the dimensions of the boat. Some landing centers and lagoons in islands such as Lakshadweep, the water depth available is restricted. The boats to be operated from these places are to be designed with low draft.

Freeboard

The freeboard of long liners and hand liners are to be minimum so that the line fishing can be conducted easily from these boats.

Hull shape

A very important factor which decides the stability, speed, sea kindliness and fuel consumption is the hull geometry. A bulbous bow fitted in the forward portion below the waterline will increase the speed of the vessel. But this has to be designed and constructed properly. The bilge keel fitted just below the water level in the mid ship area reduces the rolling of the boat.

Other facilities such as accommodation, toilet and galley

At present the crew are sleeping in the wheel house of the boat. There is no toilet and galley facility even in the deep sea going fishing vessels. Additional space will have to be provided for accommodation, galley and toilet.

Selection of machinery and equipment

The choice of main engine, reduction gear box, winch, refrigeration system and other items shall be in such a way that spare parts are available locally and the service of the manufacturer or their representative is available locally.

Safety requirements

Necessary fire controlling appliances, life saving appliance and light and sound signals are to be included in the design of the boat.

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Rules and regulations

The rules and registration regulations play an important role in the selection of main dimensions of the boat. For example, the vessels which are having a registered length of 20 meters and above are to be designed in accordance with the rules of classification society and registered with mercantile Department. This will increase the cost of construction of the boat. Moreover the operational expenditure will also increase for such vessels.

Types of boat construction

There are two types of boat construction in our country: First, Construction based on the design developed by experienced carpenters. Second, construction based on standard design procedure of a marine vehicle and construction by a properly established yard.

Boats built based on the design developed from the experience of fabricators

Existing and proven design of a boat will be picked by the builder. Sometimes they follow the same design or apply minor modifications to meet the requirements of the owner and build a new vessel. The next person will modify this one and end up with a third variety. Like this the fourth and fifth boat will be entirely different from the parent boat. They normally complete the construction and take the sea trials. After trials if the product is found to be performing well, it is called a successful boat. But this method becomes a very expensive experiment. Unfortunately the stability of these boats is not tested.

Modifying a boat which is already built is a very difficult task and expensive and extra time and efforts will have to be spent. This becomes very dangerous when the stability requirements are not met. There are several occasions when the trial design and constructions ending up as poor performing vessel. A boat was constructed with larger breadth. After construction it was realized that the speed is less. This ended in many difficulties such as the vessel reaching the fishing ground late compared to other boats and could not make very good catch. The boat crew was not interested in working on a slow boat. The fuel cost went up. On another occasion, it was found that an overpowered engine with 400 hp was fitted on a boat designed for 180 hp. The hull structure could not withstand the high vibrations and the hull cracked.

In most of the cases it can be noticed that there are no watertight partitions called bulkheads in boat constructed in this method. The water generated from melting of the ice can leak to the engine room and lead to high corrosion. The water leak from engine room to the fish storage area can contaminate the fish as this water may contain oil. Due to all these problems, it is not advised to follow this method.

Construction based on standard design procedure

The standard design procedure follows a spiral form. The basic steps involved in the design of a fishing boat are the following. Analyse some of the existing boats with the same or similar parameters and arrive at preliminary dimensions and power. Make a preliminary General

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Arrangement plan to meet the required capacities for diesel, water, fish storage, provision, crew requirements and power. Calculate the total requirement of material, machinery, equipment, etc Calculate the total cost. The preliminary assessment of stability is also to be done. When the requirements of the owner are met for the above cost, the final design will be prepared. Go to the previous stages whenever any of the above requirements is not met. Then carry out the modification and proceed from that step.

Detailed design

The following steps explains the design of a fishing vessel.

Prepare the hull form or the lines plan The plan, profile view and sections will be drawn

Calculate the hydrostatic particulars of the vessel: From the above lines plan the displacement, metacentric height, position of center of gravity will be calculated.

Prepare the preliminary General Arrangement plan

Finalise the power and machineries/equipemnts for the vessel

Adopt a class rule and calculate the scantlings: The structural design of the boat will be done which gives the details of the different structures in the boat. The thickness of the

plates at keel, bulkhead, transom and deck, size of the transverse and longitudinal frames and bulkhead stiffeners can be obtained from this plan

Each frame is to designed individually so that the builder can construct all the frames with the help of the above design

The power required for the winch can be either taken from the Power Take Off (PTO) from the main engine or separately from a generator. The hydraulic power required for windlass, winch or steering purpose can be taken from the main engine or from a

Calculate the stability at this stage for a check: From the hydrostatic values the initial calculation of stability can be done

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generator.

Design of propulsion system: The diameter and length of the propeller shaft, the diameter and pitch of the propeller and the diameter and thickness of the bush at the

ends will be determined. Design of steering system

The area of the rudder, the detailed design of the rudder stock and the bush

Design the fish hold: RSW/Slurry/Refrigerated/ Insulated store

Design of accommodation, navigation bridge, galley, toilets, stores

Estimate the final weight, center of gravity and check the stability and speed

Finalise the design

Such a plan is given in the Fig. 1. Modify the design incorporating changes in the structural plan, for any stability and speed problems.

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Fig. 1. General Arrangement plan of a 19.75 m long liner cum gill netter cum trawler

Construction and supervision

The detailed structural design will be based on the scantling rules by any of the International Association of Classification Societies. The Classification rules specify the mechanical properties of the steel plates/ laminate and sections to be used for marine crafts. Indian Register of Shipping (IRS) is such an agency in India. The construction of a steel vessel is to be undertaken by a yard with facilities such as materials testing, raw material storage, welding, machining, fire safety and skilled employees. Qualified supervisors are essential to construct fishing vessels so that strict adherence to the design requirements can be ensured. For FRP vessel construction, enclosed yard with humidity control is very important. The raw materials such as resin, glass mat and chemicals are to be stored safely. The fiberglass boat is constructed in a continuous process and the hull is made in a single mould or two parts. These parts of the boat hull are joined water tightly. In FRP boats sufficient overlapping of the glass mat is to be provided, especially in the keel and deck joints. During construction there can be again some minor modifications or compromises within the limit of the rules to suit the availability of plates,

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sections, machinery and equipment. During construction, proper care has to be given for the joints. This aspect is very important in keeping the water tightness of the boat. For wooden constructions, only well-seasoned wood without any sap wood shall be used. In the case of steel boats, only marine plates shall be used for the construction. During the design stage sufficient care has to be given for the design of the joints. The type of welding, length of weld and the quality of the welding rod are to be specified during the design in the steel boat construction. The wooden joints are to be with sufficient strength and tightness.

Quality of materials and machinery

The quality of raw materials, welding rod, fiber glass, resin, wood, machines, pumps, winch and other items can be ensured with the help of the selection by an experienced person and installation under the guidance of this person. This will help in the proper and economical maintenance of the boat. The water tightness of hull is to be ensured after the construction.

Stability of boats

After the construction, the inclining experiment will be conducted in calm water in a protected area of the port. This test will give the position of the center of gravity of the vessel. The stability of the vessel can be calculated with the help of hydrostatic particulars and righting lever at different loading conditions. The calculation of stability and preparation of trim and stability booklet is important for all sea going fishing vessels.

Conclusion

The design of a boat requires careful consideration of input parameters so that the output will be a good boat. The systematic approach with the help of calculations will result in a stable vessel with fuel efficiency. Proper supervision and skill is required to construct a safe and standard vessel.


Gillmer, T. C. and Johnson, B. (1982) Introduction to Naval Architecture, E & F.N SPON

Hind, J. A. (1982) Stability and trim of fishing vessels and small ships, Fishing News Books, London

45-65 p

John Fyson (1985) Design of small fishing vessels, Fishing News Books, London

Rossel, H.E. and Chapman, L.B. (1958) Principles of Naval Architecture, Society of Naval Architects and Marine Engineers

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Energy use in fishing Paras Nath Jha and Leela Edwin*

Fishing Technology Division, ICAR-Central Institute of Fisheries Technology, Kochi


Introduction

Fisheries sector is promising way for employment and income generator to huge chunk of the society. Global fish production peaked at about 171 million tonnes in 2016, with aquaculture representing 80.3 million tonnes and 90.9 million tonnes of the total capture production (FAO, 2018). Fishing has been an occupation since time immemorial. Fish harvest is one of the oldest forms of food production; it directly contributes approximately 10% of the total animal protein intake by humans. In per capita terms, food fish consumption grew from 9.0 kg in 1961 to 20.2 kg in 2015, at an average rate of about 1.5 percent per year. Preliminary estimates for 2016 and 2017 pointed to further growth to about 20.3 and 20.5 kg, respectively (FAO, 2018). All over the world diverse range of fish catching methods with different fishing gears are used by small-scale artisanal to large-scale industrial systems. Small-scale fisheries contribute about 50% of global fish catches which leads to generation of employment for more than 90% in world’s capture fisheries. Worldwide about 59.6 million people are directly or indirectly involved in fisheries and aquaculture (FAO, 2018) Out of which about 37% people are directly dependent on fishing and rest are in other allied activity like processing and marketing activities (Matthews et al., 2012).

Fishing involves the dissipation of energy to accomplish its primary activity i.e. harvesting

of fishery resources. While the active cost of fishing is less understood, and consequently receives less attention than the direct impact on fishery stocks and marine ecosystems. It is precisely the availability of fossil energy that enables fisheries to continue even when stocks are in decline. Subsequently, analyses of energy in terms of fuel consumption in fisheries, and changes in energy use over time, can also provide a powerful tool to know how of the stock health in fisheries sector. The fisheries sector is highly external energy dependent sector which is mainly on fossil fuels. Inland fisheries are a low carbon footprint food source compared to marine fisheries. Inland fisheries often use non-mechanized gear that does not require fuel (consumed by boats using active fishing gear in major marine fisheries) (Clark and Tilman, 2017). Global greenhouse gas emissions would be significantly higher if inland fisheries had to be replaced with other forms of animal protein production (Lymer et al., 2016b; Ainsworth and Cowx, 2018) Energy Inputs to Fisheries

In the year 2017-18 the marine fish landings of India was 3.88 million tonnes which is 6.9% more than the preceding year (CMFRI, 2018). There are 1,99,141 fishing vessels operates in marine fisheries sector of India out of which mechanised, motorised and traditional artisanal vessels contributes about 36.5%, 36.9% and 26.6% respectively. Where as in terms of total catch landed during year 2017-18, mechanized, motorized and artisanal contributed around 75%, 23% and 2% respectively (CMFRI, 2012b, 2015, 2018). During the last decade, the price of fuel and other energy sources was on a rising trend. In 2001, fuel was estimated to account for 21% of

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revenue from landed catch, whereas in 2008 this increased to about 50%. Fuel use varies usually with type of fishing and level of effort, but as one of the key cost components over which the fisheries sector has no direct control. Profitability and livelihoods are potentially highly sensitive to energy costs (FAO, 2015). A few studies have been conducted in Indian context for energy analysis of fishing systems and operations (Edwin & Hridayanathan, 1997; Boopendranath, 2000; Boopendranath & Hameed, 2009; Boopendranath & Hameed, 2010; Vivekanandan, 2013; Ghosh et al., 2014). In Indian marine fisheries, the boosted fishing effort and efficiency in the last five decades has led to in considerable increase in fuel consumption, which is equivalent to CO2

emission of 0.30 million tons (mt) in the year 1961 to 3.60 MMT in 2010. The CO2 emission has increased from 0.50 to 1.02 t for every tone of fish caught during the period. Large differences also reported by authors in CO2 emission depends upon craft types and age. In 2010, the larger mechanized boats (with inboard engine) emitted 1.18 t CO2/t of fish caught, and the smaller motorized boats (with outboard motor) 0.59 t CO2/t of fish caught. Author reported that among mechanized craft, trawlers emitted more CO2 (1.43 t CO2/t of fish) than the gillnetters, bagnetters, seiners, liners and dolnetters (0.56–1.07 t CO2/t of fish). (Vivekanandan, 2013). Many authors studied and reported effect on environment by capture fisheries using life cycle assessment method. Tyedmers (2001), Ziegler et al. (2003), Thrane (2004, 2006), Ellingsen & Aanondsen (2006), Ziegler & Valentinsson (2008), Vázquez-Rowe et al. (2010a and 2010b), Ramos et al. (2011) and Svanes et al. (2011). Gulbrandsen (2012) reported 10% and 20% reduction of engine rpm will reduce 20% and 40% fuel consumption respectively. He also opined that, compared to 2-stroke out board petrol engines inboard diesel engine consume 62% less fuel at same speed. Boopendranath (2009, 2010) also advocated use of four-stroke fuel-efficient diesel engines compared to two-stroke engines as it is fuel efficient. He also mentioned fuel consumption drastically increases as maximum speed is approached and a reduction of 10% in speed could lead to 35 % savings in fuel. Study revealed the technical efficiency of the different types of ring seines using lesser horsepower engines performed well with respect to the catch per adjusted horsepower (Edwin & Hridayanathan, 1997). Energy requirement have been used to evaluate the performance of food production systems for over a hundred years in terms of energy input and carbon footprint.

After Gerald Leach’s handbook ‘‘Energy and Food Production’’ published in 1976 which

included data on the major culturally mediated energy inputs to six fisheries from four continents. Since then researchers in various parts of the world have started working on energetics of fisheries from different perspectives. From an energetic perspective, fishing is a set of different process (from fabrication of craft/gear to landing of catch) in which different forms of energy are dissipated in order to capture fish and shellfish. However, as of now very few fishery-specific energy analyses have systematically attempted to account for energy use. In most fisheries energy inputs are required to propel fishing vessels and deploy fishing gears. The three dominant forms of energy dissipated to these ends include animate, wind, and fossil fuel energy

Animate Energy

Animate energy is common to all fisheries irrespective of their technological sophistication. In traditional artisanal fisheries sector, human muscles is still source of the energy used for propulsion scouting, deploying/hauling the gears and catch handling. Human animate energy inputs remain part of the production equation, they are generally counter coursed by the

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inputs of wind energy. Unlike fisheries sector, preindustrial agriculture scenario where a wide variety of animals were domesticated to provide important secondary sources of animate energy. Wind Energy

For as long as people have sailed, it is likely that wind energy has been used to support

fishing activities. Wind energy only allowed fishing vessels to be propelled but it facilitates other supporting activities too. Specifically, various trawl or dragger fisheries in which gear are towed were almost all first developed within the context of sail fisheries. Fossil Fuels

Fossil fuels are dominant form of source of energy used in fishing. It started in England at

late 1800s, when coal-fired steam engines installed on trawl fishing vessels for propulsion and net hauling first time. With the advantages of improved power and speed, also ability to operate against of the wind more efficiently, it expanded rapidly. Up to late 20th century the coal- and oil-fired steam engines were in use on fishing vessels, subsequently it shifted towards internal combustion engine. In the early 1900s Gasoline and diesel based internal combustion engines were first adapted for use on fishing boats. After 2nd world war the size of the global fishing fleet increased along with engine power. In other hand relatively small engines are also introduced into small-scale fisheries round the globe. These both trend of increasing dominance and size of engines, resulted surprising enhanced fossil fuel consumption for the world’s fish harvest sector. Motorised and mechanised fishing is based on fossil fuel, which is non-renewable and scarce. Fossil fuels produce carbon dioxide in atmosphere which leads to 'greenhouse effect' and other toxic pollutants which are harmful to the environment and human kind. Greenhouse effect leads to irreversible climatic and oceanographic changes (Endal, 1989b; Hill et. al., 1995; TERI, 1999). The escalated oil prices may severely affect the economic viability of fishing. The Relative Importance of Direct and Indirect Energy Inputs

In modern fisheries the major direct and indirect energy inputs can be systematically analysed using process analysis and input-output techniques. Mostly direct fuel inputs are used primarily for vessel propulsion. On average direct fuel energy inputs account for between 75 and 90% of the total energy inputs, irrespective of the fishing gear used or the species targeted. Remaining 10 to 25% is generally composed with vessel construction and maintenance, and the provision of labour, fishing gear, bait, and ice if used which depending on the character of the fishery and the scope of the analysis conducted. The secondary energy-consuming activities, which include on-board processing and storage is negligible compared to primary energy consumption in terms of fuel burned. But squid jigging is extreme example of interesting fisheries in which relatively large proportion of fuel inputs are used for activities other than vessel propulsion. These include mainly batteries of high intensity lamps, automated jigging machines, and on-board storage facility etc. The energy requirement is met by diesel-fuelled generators to attract, hook, and preserve the catch while fishing. On an average the non-propulsion energy demands account for 40% of the total fuel burned. Out of total indirect energy inputs, largest fraction account for building and maintaining the fishing vessels. This is mainly due to vessel’s major components (hull, superstructure, decks, and fish holds) are fabricated basically from energy-intensive materials such as aluminium and steel as compared to wood or fiberglass.

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Boat constructed with aluminium or steel found that the embodied energy inputs are

higher than fiberglass & wood. Mostly energy analyses of fisheries are on evaluating the direct fuel inputs to fishing. It somehow narrow the focus which reflects the facts that fuel inputs dominate the energy profiling of fishing and also analysis of indirect energy input which is actually labour intensive and time consuming. Therefore, in order to ease the comparison in fisheries sector, only the direct fuel energy inputs to various fisheries is considered. The energy intensities of various fisheries are expressed in terms of the litres of fuel burned per live weight tonne of fish or shellfish landed. The significance of energy and fuel in the fishing sector and its vulnerability to changing energy supplies and prices has highlighted the importance to review the sector’s energy and fuel needs. In the holistic context, energy and fossil fuel relations in food production have been subject to notable interest for some decades. These have developed towards detailed analyses of energy and the carbon footprints of various food commodities. Energy use is now important in comparative resource-use analysis, potential trade trends, and in carbon and related greenhouse gas (GHG) impacts in climate change and its mitigation (FAO, 2012).

Related terms linked to fuel and energy use

Energy used in the fisheries sector either directly or indirectly, commonly converted to work in the form of motive and propulsive hauling and other allied work. Energy is also used in producing various capital items and raw material inputs.

Carbon footprint assessments

Which connect the energy use in terms of total set of greenhouses gases that are emitted

at different stages of a product's life cycle. The most recognized methodologies used for a carbon footprint assessment are based upon the ISO 14044 standard and the PAS 2050. This can be done with modern software application like SimaPro, GaBi etc.

Climate change processes and impacts

Where use of fossil fuels may add to GHG production, where mitigation features of various aspects of the aquatic supply chain could become important (potentially changing economic incentives), and where impacts of climate change will result in changing energy requirements in various parts of the fishery sectors.

Capture fisheries systems and structural descriptions

In different systems the input levels can be significant, and changing fuel costs are likely to different in each class of fishing activity viz. small-scale, artisanal and inshore fisheries, Coastal industrial fisheries, Distant-water fisheries

Energy use can be defined and measured in a number of ways as:

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Direct fuel use Primarily liquid petroleum products (diesel, petrol, kerosene, liquefied natural gas [LNG],

petroleum and materials such as wood or coal – defines the specific usage of a product by quantity or calorific value of fuel.

Total direct energy use

It is broad system of measurement where the total of fuel, electricity and other sources of energy input are taken in consideration. This gives a more comprehensive picture of use and comparison when fuel use is not the only energy element.

Industrial energy use

Assesses the energy required to manufacture basic element which acts as a row material for capital input or operating inputs in the process, e.g. steel, timber, synthetic fibres, plastics in vessels, gear. This total is then related to the outputs.

Embodied energy

It takes a more holistic approach, in addition to industrial energy it also includes photosynthetic energy input for biological processes of ecosystem and food chain supply in fisheries resources.

Renewable and non-renewable energy use

In any of the above categories, the specific sources of energy is renewable (solar, wind, tidal, hydropower) or non- renewable (derived from fossil fuels). Key energy elements and linkages

The primary energy elements are fuel for propulsion, and for larger vessels, power supply for a range of ancillaries. The relationship between fishing effort, fishing methods, distance to fishing grounds, vessel speed and fuel efficiency of hulls, engines and propulsion systems are all key factors. Linking with stock conditions and market values, these are all reflected in operating costs, the profitability of fishing and the level and choice of activity. In most forms of fishing activity, fuel costs have direct implications for viability. Types of fishery, conditions of fishing and market prices will all determine the impact of fuel prices, as will specific conditions of the fishing enterprise. Impacts of rising fuel prices and reduced profitability, including the value of capital assets used in the sector, can extend widely. Shorter-term changes can be accommodated by scrapping older or more inefficient vessels, selling and writing down capital values (and hence financing and depreciation costs),. Poor profitability will inhibit the building of new fishing vessels, and decrease fleet size even at global level. In the absence of external actions, such as fuel subsidies or market interventions, rising fuel prices will drive out unprofitable fishing businesses, and will tend to reduce fleet size. Depending on the nature of the fishery, this may reduce output, or improve vessel yields and overall economic and fuel-use

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performance. However, various forms of inertia – time lags in market responses and shorter-term support actions – might delay these changes. Current estimates of fuel use and cost

Tyedmers et al., (2005) proposed annual fuel use of about 50 million m3, 1.2% of total global oil consumption. With marine fish and invertebrate landings at 80.4 million tonnes, global average fuel-use intensity was 620 litres (527 kg) per live weight tonne, or about 1.9 tonnes of catch per tonne of fuel. Fishing vessels released some 134 million kg of carbon dioxide (CO2) into the atmosphere at an average of 1.7 kg of CO2 per tonne of live-weight landings. They further noted that these were likely to be serious underestimates, as they did not account for freshwater fisheries or for substantial IUU catches. Global fisheries were estimated to use 12.5 times the amount of fuel energy as their edible-protein energy output, which, although significantly inefficient, compared well with a number of other animal-protein production systems.

In context of Indian marine capture fisheries, the substantial increase in fossil fuel noticed

due to increased fishing effort and efficiency during the last five decades. Which has resulted in, equivalent to CO2 emission of 0.30 million tonnes (mt) in the year 1961 to 3.60 mt in 2010. Roughly for every tonne of fish caught, the CO2 emission has increased from 0.50 to 1.02 t during above said period. There is large differences in CO2 emission among the types of craft which made of different material. In 2010, mechanized and motorized boats emitted 1.18 t CO2/t and 0.59 t CO2/t of fish caught respectively. Among the mechanized craft, the trawlers emitted higher CO2 (1.43 t CO2/t of fish) than the gillnetters, bagnetters, seiners, liners and dolnetters (0.56–1.07 t CO2/t of fish). (Vivekanandan, 2013).

Conclusion

Global fishing practice is highly varied. Harvest is a process in which capture of aquatic animals takes place using a variety craft and gear, mostly vessel-based fishing gears. The major forms and quantities of energy inputs used in fishing operation also vary extensive. Most of the fisheries, particularly large-scale fisheries, over the past half-century, input of energy/fossil fuel dominate energy profile. Cost and use of fuel is a significant issue in the capture fishery sector. It represents significant input cost in most of the fishing operations, except for non-motorized sector. Impact of fuel price is verifying with economic conditions and location, generally developing countries, distant-water fishing and poorer market conditions will have and greater impacts. The data on fuel consumption can be extrapolated to get the idea about fleet, levels of fuel used, its cost and also help in better management of fishing fleets along with resource and efficiency considerations. References/suggested editing

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Ziegler, F. and Valentinsson, D. (2008) Environmental life cycle assessment of Norway lobster (Nephrops norvegicus) caught along the Swedish west coast by creels and conventional trawls-LCA methodology with case study. International Journal of Life Cycle Assessment. 13: 487-97

Vivekanandan, E., Singh, V. V. and Kizhakudan, J. K. (2013) Carbon footprint by marine fishing boats of India. Current Science. 3: 361-366

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LCA Analysis: Case Study of Ring Seine Fishing Systems of Kerala

P.H. Dhiju Das* and Leela Edwin

ICAR-Central Institute of Fisheries Technology, Kochi *E-mail:[email protected]

Introduction

Fish capture technology encompasses the process of catching any aquatic animal, using any kind of fishing methods, often operated from a vessel. Use of fishing methods varies, depending on the types of fisheries, and can range from a simple and small hook attached to a line to large and sophisticated large fishing vessels. The targets of capture fisheries can include aquatic organisms from small invertebrates to large whales, which might be found anywhere from the ocean surface to 2000 meters deep. The large diversity of target species in capture fisheries and their wide distribution requires a variety of fishing gear and methods for efficient harvest.

In recent decades major improvements in fiber technology, along with the introduction of

other modern materials, have made possible, for example, changes in the design and size of fishing nets. The mechanization of gear handling has vastly expanded the scale on which fishing operations can take place. Improved vessel and gear designs, using computer-aided design methods, have increased the general economics of fishing operations. The development of electronic instruments and fish detection equipment has led to the more rapid location of fish and the lowering of the unit costs of harvesting, particularly as this equipment becomes more widespread. Developments in refrigeration, ice-making and fish processing equipment have contributed to the design of vessels capable of remaining at sea for extended periods.

Although these technologies are largely available, those actually introduced in many

small-scale fisheries may amount to no more than motorizing a dugout canoe, use of modern and lighter gear or introducing the use of iceboxes to ensure the quality of the product landed. The impact of such changes, however, has considerably increased landings and the earnings of fishers, and underlines the need for effective management to prevent excessive fishing effort. The emphasis of much recent technical innovation has been focused on greater and more appropriate selectivity of fishing gear so as to reduce negative impacts on the environment. Impact on Fisheries

Most of the environmental concerns with respect to commercial fishing mainly focus on

direct impacts to targeted species (Pauly et al., 2002; Christensen et al., 2003; Myers & Worm, 2003), bycatch and discards (Alverson et al., 1994; Glass, 2000), alterations to benthic communities (Johnson, 2002; Chuenpagdee et al., 2003), and modifications to trophic dynamics (Jackson et al., 2001). These concerns do not cover all aspects related to the environmental impacts of fishing activities (Iribarren et al., 2010a and Iribarren et al., 2011). In this background, LCA has arisen as a suitable methodology to undertake the environmental assessment of products through a life-cycle approach (Pelletier et al., 2007). LCA is recognized worldwide as a useful tool for assessing environmental aspects and potential impacts associated with products or processes

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(ISO 2006a, 2006b), and can be a suitable methodology for the analysis of the environmental performance of fisheries (Pelletier et al., 2007; Vázquez-Rowe et al., 2010a; 2010b). LCA is a compilation of the inputs and outputs and evaluation of potential environmental impacts of a product throughout its lifecycle (ISO 2006a, 2006b; Pelletier et al., 2007). LCAs are used to identify environmentally preferred products or methods and to provide insight into the main causes of the environmental impact of a product or process and for determining design priorities. LCA can be used as a support tool for policy and decision-making or as a methodology for benchmarking in terms of eco-efficiency (Vázquez-Rowe et al., 2010a). In India, till now no study has taken place related to LCA for trawl fishing wherein impact categories such as Global warming potential, Abiotic depletion potential (fossil), Acidification potential, Eutrophication potential, Marine aquatic ecotoxicity potential, Ozone layer depletion potential and Photochemical ozone creation potential are considered. The Carbon Footprint (CF) is just one output from the life cycle assessment. The Carbon Footprint is a measure of the amount of CO2 and other GHG emissions that is directly and indirectly caused by an activity or is accumulated over the life stages of a product. This is usually expressed in kilograms of CO2 equivalents (Gerber et al., 2010). CO2 equivalents represent the equivalent concentration of CO2 that would cause the same warming effect on the atmosphere.

LCA allows for comprehensive evaluations to be made on the environmental impacts

related to products over their whole life cycle, encompassing infrastructure, energy provision, extraction of raw materials, manufacturing (cradle-to-gate), distribution, use and final disposal (cradle-to- grave) (ISO, 2006b). LCA is thus a tool aimed to, among other purposes, identify opportunities for improving environmental performance and inform decision makers on the environmental performance of products, product systems and even their alternatives (ISO, 2006a). Energy analysis are relevant in relation to fisheries due to the accepted importance of fuel consumption in fleet operations (Tyedmers, 2001) and associated environmental impacts (Thrane, 2004a; Schau et al., 2009; Driscoll & Tyedmers, 2010). Carbon footprint is often considered as a sub-set of LCA (EC/JRC, 2007) and is closely associated to fisheries LCA due to the strong impact of fuel consumption (Avadi & Freon, 2013). LCA was first introduced in the late sixties in the United States and was first used to compare resource consumption and environmental impact associated with containers of beverages (European Environment Agency, 1997). In 1992, at the UN Earth Summit, LCA methodologies were announced to be the most promising tool for environmental management tasks (European Environment Agency, 1997). Studies by Thrane (2006) points out that if all flatfish in Denmark is caught by Danish seine nets or gillnets it would theoretically be possible to save 30 million litres of fuel per year within the Danish fishery or 15% of their total fuel consumption in a year. Pioneering studies on LCA and CF applied to Indian fisheries include Ghosh et al. (2014) has studied carbon footprint of marine fisheries of Visakhapatnam with targeted species and fishing methods. Ravi (2015) studied the structural changes and life cycle assessment in mechanised trawl fishing operations of Kerala. Das and Edwin (2016) conducted the LCA analysis of Kerala Ring Seine Fishery in a cradle to grave approach. Motorized fishery impact studies were conducted by Edwin and Das (2016). In recent times, significant changes have taken place in capacities of the fishing craft, installed engine horse power, fish handling equipment and fishing gear. The increasing oil price, growing environmental consciousness and the change in availability of fish catch necessitates the reduction in energy use and hence there is a need for re-estimation of energy requirement of fishing systems by application of modern approaches like Life Cycle Assessment and Carbon Footprint. Fish harvesting systems are dependent on fossil fuels which are non-renewable and

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releases high levels of carbon dioxide to the atmosphere contributing to greenhouse effect. In this scenario, energy analysis are relevant in relation to fisheries Life Cycle Assessment (LCA) due to the accepted importance of fuel consumption for fleet operations and associated environmental impacts.

In this study, LCA analysis for individual ring seine fishing unit (vessel and gear) and its

operation was conducted using a cradle to gate approach. The post-harvest processes have been excluded from the system boundary as the use of catch varied with the different fishing units. So in this study system, boundary has been limited to the point at which the catch reaches the harbour.

Collecting quantitative and qualitative data for every unit process in the system was the

most cumbersome part of LCA analysis. PE- Gabi LCA software was used for analysis of the data (ISO: 14040, 2006). As per the requirements of this software the data for each unit process can be classified as energy inputs, raw material inputs, ancillary inputs, other physical inputs, products, co-products, wastes etc. A case study of ring seine fishing system of Kerala System boundary

All major actives associated with the inputs for assessment of LCA are depicted in the system

boundary chart comprising of three sub systems is given in Fig.1. The system boundary defines which processes will be included in, or excluded from, the system and describes the processes and their relationships. In this study LCA analysis for individual fishing unit (vessel and gear) and its operation was conducted using a cradle to gate approach. The post-harvest processes have been excluded from the system boundary as the use of catch varied with the different fishing units. So in this study system boundary has been limited to the point at which the catch reaches the harbour.

Fig.1. Block diagram of the studied system. Dotted line represent the system boundary

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Functional Unit

LCA is generally organized into a four step process viz. goal and scope definition, inventory analysis, impact assessment and interpretation of results. The functional unit taken for the study is one ton of ring seine catch. The functional unit (FU) is a quantified definition of the function of a studied system and it provides a reference to which the inputs and outputs can be related (ISO:14040, 2006). The major operational inputs and outputs associated with fishing activity of mechanised and motorised ring seine system in the south east Arabian sea was collected and analyzed. As per CML 2001 methodology ten environmental impact categories, namely abiotic depletion potential elements (ADP elements), abiotic depletion potential fossil (ADP fossil) acidification potential (AP), eutrophication potential (EP), global warming potential (GWP), human toxicity potentials (HTP), marine aquatic eco-toxicity potentials (MAETP), stratospheric ozone depletion potential (ODP) and finally photo-oxidant formation potential and terrestrial eco toxicity potential (POFP and TETP) were chosen to quantify the environmental impacts associated with the activities. Data acquisition: - Fishing Craft

Details of materials used for construction of fishing vessel were collected from local boat building yards by interviews with boat builders, skippers and log books maintained at boat yards and vessels. Quantity wise data on materials like steel (for hull, engine, propeller shaft etc.) welding rod, electricity for welding, grinding, light (unit kwh) plywood for deck, wooden material, alloy for propeller, fiber glass mat, resin, other ingredients (accelerator, catalyst, etc.) material, details of primer, paint, antifouling paint, transportation etc. were collected. Collected quantitative vessel characteristics were amortized with the life span of the fishing vessel and calculated for one ton landings. Inventory data is given in Table-1

Table 1. Inventory for ring seine gear (data for one ton of catch)

Particulars Mechanised ring seiner Motorised ring

seiner Paints (surface primer, paint, antifouling paint, etc.) 1.79E-01 1.31E-01 Electricity 1.43E-01 1.92E-02 Electrodes 8.82E-02 6.42E-04 Fiber reinforced plastic 4.48E-02 8.03E-01 Gunmetal Material 2.56E-02 - Hard wood log mix 8.82E-02 4.81E-01 Limestone 1.92E-02 1.05E-02 Plywood board 9.62E-03 1.40E-01 Steel 2.03E+00 2.57E-01

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Fig. 2. Inventory network of ring seine gear

Data acquisition:- Fishing Gear

Quantity of polyamide multifilament webbing, high density polyethylene webbing, polypropylene rope, plastic floats, lead sinkers, brass rings were collected from net fabrication sites and net making factory. In fishing gear webbing life span is considered as Two year and the quantitative inputs were expressed in teams of per ton sardine landings. Inventory data for Ring seine gear is given in Table-2

Table 2. Inventory for ring seine gear (data for one ton of catch)

Particulars 1000 m Mechanised

ring seine gear 750m Motorised ring seine gear

Polyamide Webbing Material 1.42E+00 9.16E-01 HDPE Webbing Material 3.16E-01 2.62E-01 Polypropylene Rope 4.34E-01 3.40E-01 Lead Sinker 9.87E-01 5.24E-01 Brass 1.03E-01 1.05E-01 Plastic float 3.16E-01 2.88E-01

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Fig. 3. Inventory network of ring seine gear Data acquisition:- Fishing Operation Details of engine and its horsepower, number, types and size of fishing gear, details of fishing operations including the number of fishing days in an year, time of shooting the net, time of hauling, number of hauls, fuel used (diesel, petrol, kerosene and lubrication oil) were collected from skippers and fishing vessel owners and species wise catch details were collected from fishermen cooperative societies which maintained the daily landing log books (Table-3).

Table 3. Inventory for ring seine operation (data for one ton of catch)

Particulars Mechanised ring seine operation

Motorised ring seine operation

Diesel 89.50684 Petrol 4. 945890 8.114803

Kerosene 32.44179 141.9945 Lub oil 1.316277

Fig. 4 Inventory network of motorised ring seine operation

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Fig. 5. Inventory network of mechanised ring seine operation

Inputs excluded from system boundary

Harvest loses during transfer of catch at the landing center, solid and liquid waste generated in the fishing vessel, discharges of such matter into the sea were not taken into account the study due to insignificant quantity and lack of data. Quantitative data on electric wiring circuits, navigational equipment also do not come under the purview of this study. Environmental performance of Ring seine fishery

Results show that fish catch landed by motorized ring seine fleet is having higher impact

when compared to mechanized ring seine fleet except ADP element and ODP it due to the high use of lead weight and polyamide webbing in mechanized fleets. While comparing motorized fleets (Table-8), impact of ADP fossil, AP, EP, GWP, HTP and POCP shows more than 20% higher impact than mechanized fleet with a higher value of 24% in GWP. Table 5. Combined environmental performance and Mass allocation of impact categories in

terms of one ton of ring seine landing

Impact Category Mechanised Motorised % difference motorized / mechanized landings

ADP elements 3.50E-03 1.94E-03 -80.24% ADP fossil 4.97E+03 6.45E+03 22.89% AP 1.24E+00 1.57E+00 21.02% EP 5.97E-02 7.51E-02 20.41% GWP 3.95E+02 5.22E+02 24.26% HTP 2.83E+01 3.56E+01 20.60% MAETP 1.06E+04 1.12E+04 4.96% ODP 3.20E-09 2.47E-09 -29.95% POCP 8.92E-02 1.13E-01 20.71% TETP 2.14E-01 2.38E-01 10.08%

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Different hot spots have been identified in the study of ring seine fishery through motorized and mechanized activities. Through this study some important interventions can be proposed for the improved efficiency of the fishery. The reduction of fuel through reduction of speed can bring about a major change. Gulbrandsen (2012) has opined that 10% reduction of engine rpm will reduce 20% fuel consumption and 20% reduction in rpm will reduce 40% fuel consumption. Proper maintenance of vessel hull also contributes a major role in fuel use. In tropical conditions hull fouling increases fuel consumption at 7% in first month of operation and up to 44% after six month of operation if antifouling paint is not used (Gulbrandsen, 2012). Vessel drag reduction through improvised hull shape will help in energy efficiency up to 20% (Schau et al., 2009). In motorized fleets, replacement of high energy consuming 2-stroke out board engine to inboard engines will reduce the fuel usage. According to Gulbrandsen (2012) when compared with 2-stroke out board petrol engines inboard diesel engine consume 62% less fuel at same speed. Ring seine operations are conducted based on the occurrence of small pelagic fish shoals. The chance of occurrence of fish as small pelagic shoals mainly depends on the sea surface temperature and chlorophyll concentration (Pillai and Nair, 2010). Boopendranath and Hameed (2012) observed that Kerala ring seine fuel consumption per kg fish landed varied with lower fuel consumption during the month of May to December and higher in January to April. The high fuel consumption during this period is due to the movement of pelagic shoals towards deeper depth, because of distortion caused by direct sunlight (Pillai and Nair, 2010) which make the fishing more difficult and increase the total fish shoal searching time and leads to the wastage of fuel. During the study period it is observed that an average ring seine fishing trip takes 12.28 ± 2.06 hours of operation, including the cruising time to the fishing ground and the fishing operation takes less than 45% of the total fishing time and major time was spent for searching the fish shoals for which maximum fuel is consumed. Knowledge about the spatial distribution of fish over the time and the effective use of Potential Fishing Zone (PFZ) forecast based on sea surface temperature and or surface chlorophyll concentrations can help to reduce the searching time and environmental impact.

Replacement of low durable polyamide webbing with highly durable Ultra-High Molecular Weight Polyethylene (UHMWPE) will help to increase the life span of webbing (Thomas and Edwin, 2012) which will lead to reduction in detrimental effect on environmental impact factors. Appropriate use of lead sinkers will reduce the number of sinker per meter of sinker line which will also reflect in environmental factors like ODP. Compared to mechanized and motorized ring seine units, traditional ring seine units are least contributing to the environmental factors. LOA of motorized ring seine units restricted to 15m for near shore operation with smaller size of ring seine gear and mechanized ring seine units with optimized gear for off shore operation will help to reduce the environmental impacts. References/suggested reading Alverson, D.L., Freeberg, M.H., Murawski, S.A. and Pope J.G. (1994) A global assessment of fisheries bycatch

and discards. FAO FISH. Technical Paper no. 339. FAO, Rome, Italy

Avadi, A. and Freon, P. (2013) Life cycle assessment of fisheries: A review for fisheries scientists and managers, Fisheries Research 143: 21-38

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Boopendranath M.R. and Hameed M. S. (2012) Gross Energy Requirement in Fishing Operations, Fishery Technology 50 : 27 – 35

Christensen, V., Guenette, S., Heymans, J. J., Walters, C. J., Watson, R., Zeller, D. and Pauly, D. (2003) Hundred-year decline of North Atlantic predatory fishes. Fish and Fisheries, 4(1): 1–24

Chuenpagdee, R., Morgan, L.E., Maxwell, S.M., Norse and E.A., Pauly, D. (2003) Shifting gears: assessing collateral impacts of fishing methods in US waters. Frontiers in Ecology and the Environment 1 (10): 517–524

Das, D.P.H. and Edwin, L. (2016a) Motorized fishing contributions to climate change. FishTech Rep 2(2), July-Dec 2016: 1-3

Das, D.P.H. and Edwin, L. (2016b) Ring Seine Fishing Systems of Kerala and its Life Cycle Assessment, LAP LAMBERT Academic Publishing OmniScriptum GmbH & Co., Germany, 252 p

Das, D.P.H. (2016) Investigations on the structural and operational changes of ring Seine Fishing Systems of Kerala and its Life Cycle Assessment (LCA) Ph. D. Thesis, Cochin University of Science and Technology, Kochi, 271 p

Driscoll, J. and Tyedmers, P. (2010) Fuel use and greenhouse gas emission implications of fisheries: management the case of the New England Atlantic herring fishery. Marine Policy 34 (3): 353–359

EC/JRC (2007) Carbon footprint: what it is and how to measure it. Ispra: European Platform on Life Cycle Assessment European Commission – Joint Research Centre Institute for Environment and Sustainability

Edwardson, W. (1976) The energy cost of fishing, Fishing News International. 15(2): 36-39

European Environment Agency (1997) Life Cycle Assessment- A guide to approaches, experiences and information sources. Folkmann Design & Promotion

Gerber, P., Vellinga, T., Opio, C., Henderson, B. and Steinfeld, H. (2010) Greenhouse Gas Emissions from the Dairy Sector, a Life Cycle Assessment. Rome, Italy: Food and Agriculture Organisation of the United Nations, Animal Production and Health Division

Ghosh, S., Rao, H.M.V., Kumar, S.M., Mahesh, U.V., Muktha, M. and Zacharia, P. U. (2014) Carbon footprint of marine fisheries: life cycle analysis from Visakhapatnam, Current Science, 107 (3): 515-521

Glass, C.W. (2000) Conservation of fish stocks through bycatch reduction: a review. Northeastern Naturalist 7 (4): 395–410

Gulbrandsen, O. (2012) Fuel savings for small fishing vessels – A manual, FAO, Rome, 57 p

Hospido, A., and Tyedmers, P. (2005). Life cycle environmental impacts of Spanish tuna fisheries. Fisheries Research, 76: 174-186

Iribarren, D., Vázquez-Rowe, I., Moreira, M. T., & Feijoo, G. (2011) Updating the carbon footprint of the Galician fishing activity (NW Spain). Science of the Total Environment, 409: 1609-1611

Iribarren, D., Vázquez-Rowe, I., Hospido, A., Moreira, M.T. and Feijoo, G. (2010a) Estimation of the carbon footprint of the Galician fishing activity (NW Spain). Science of the Total Environment, 408 (22): 5284–5294

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ISO (2006b) ISO 14044:2006, Environmental management-Life Cycle Assessment-Requirements and guidelines. International Organization for Standardization

Johnson, K. (2002) Review of national and international literature on the effects of fishing on benthic habitats. NOAA Technical Memorandum NMFS F/SPO, no. 57, Maryland, USA.

Myers, R.A. and Worm, B. (2003) Rapid worldwide depletion of predatory fish communities. Nature, 423: 280-283

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Pauly, D., Christensen, V., Guenette, S., Pitcher, T.J., Sumaila, R.U., Walters, C.J., Watson, R., Zeller, D. (2002). Towards sustainability in world fisheries. Nature 418: 689–695

Pelletier, N.L., Ayer, N.W., Tyedmers, P. H., Kruse, S. A., Flysjo, A., Robillard, G., Ziegler, F., Scholz, A. J. and Sonesson, U. (2007) Impact categories for Life Cycle Assessment research of seafood production systems: Review and prospectus. The International Journal of Life Cycle Assessment, 12(6): 414-421

Pillai, V. N. and Nair, P. G. (2010) Potential Fishing Zone advisories- are they beneficial to the coastal fisherfolk ? A case study along Kerala coast. South Ind. J. Biol. Forum. 2 (2): 46-55

Ravi, R., Vipin, P.M., Boopendranath, M.R., Joshy, C.G. and Edwin, L. (2013) Structural changes in the mechanised fishing fleet, operating off Kerala, India, Paper presented in International Symposium on Greening Fisheries towards Green Technologies in Fisheries, 21-23 May 2013, organised by SOFT(I) and CIFT, Kochi

Schau, E. M., Ellingsen, H., Endal, A. and Aanondsen, S. A. (2009) Energy consumption in the Norwegian fisheries, Journal of Cleaner Production, 17(3): 325–334

Thomas S. N. and Edwin L. (2012) UHMWPE - The Strongest Fibre Enters the Fisheries Sector of India, Fish Technology Newsletter, Central Institute of Fisheries Technology, Cochin, Vol. XXIII (4) October - December 2012

Thrane, M. (2006) LCA of Danish Fish Products. New methods and insights. The International Journal of Life Cycle Assessment, 11 (1): 66–74

Thrane, M. (2004) Energy consumption in the Danish fishery. Identification of key factors. Journal of Industrial Ecology, 8:223–239

Tyedmers, P.H., Watson, R., and Pauly, D. (2005). Fueling Global Fishing Fleets. Ambio. 34 (8): 635-638

Tyedmers, P. (2001) Energy consumed by North Atlantic fisheries. In: Fisheries’ Impacts on North Atlantic Ecosystems: Catch, Effort and National/Regional Datasets. Zeller, D., Watson, R. and Pauly, D. (eds.). Fisheries Centre, University of British Columbia, Vancouver, 12–34 p. http://www.seaaroundus.org/report/method/tyedmers10.pdf

Vázquez-Rowe, I., Iribarren, D., Hospido, A., Moreira, M.T. and Feijoo, G. (2010a) Linking fuel consumption and eco-efficiency in fishing vessels, A brief case study on selected Galician fisheries, First International Symposium on Fishing Vessel Energy Efficiency E-Fishing, Vigo, Spain, May 2010

Vázquez-Rowe, I., Iribarren, D., Moreira, M.T., Feijoo, G. (2010b) Combined application of Life Cycle Assessment and data envelopment analysis as a methodological approach for the assessment of fisheries. The International Journal of Life Cycle Assessment, 15(3):272–83

Watanabe, H. and Okubo, M. (1989). Energy input in marine fisheries of Japan. Bulletin of the Japanese Society of Scientific Fisheries, 53: 1525-1531

Ziegler, F., Nilsson, P., Mattsson, B. and Walther, Y. (2003) Life cycle assessment of frozen cod fillets including fishery-specific environmental impacts. The International Journal of Life Cycle Assessment, 8(1):39–47

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Energy Efficient and Resource Friendly Trawl Systems

M.P. Remesan Fishing Technology, Division, ICAR-Central Institute of Fisheries Technology, Kochi


Increasing fuel consumption, fuel costs, greenhouse gas emission and related

environmental and health impacts compel fisheries scientists to develop fuel efficient harvesting technologiesglobally. Tyedmers et al. (2005) reported that 50 billion litres of diesel is burnt by the global fishing fleet every year. Annual fuel consumption of the mechanised and motorised fishing fleet of India in 2010 was estimated as 1378.8 million litres releasing about 3.13 million tonnes of CO2 at an average rate of 1.02 tonnes per live weight of marine fish landed (Vivekanandan, et al., 2013).

Trawling is the most energy intensive fishing methods in the world. It consumes 5 times the fuel compared to gillnetting and long lining and 11 times than purse seining operations. To catch 1kg of fish, trawling requires 0.8kg fuel, gillnetting 0.15, long lining 0.25 and purse seining 0.07kg (Gulbradson, 1986). Fuel consumption of trawlers which depends on installed engine horse power and duration of voyage constitute 45 to 75% of operational expenditure. Ravi, et al (2015) estimated total fuel consumption of mechanised trawl sector in Kerala as 106.3 million litres @ 0.41kg/kg of fish landed.

In addition to the type of fishing method employed, amount of fuel consumption vary depending on the size and design of the vessel, engine power, speed of propulsion, type and size of fishing gear and accessories, location of the ground, skill and knowledge of the crew, atmospheric and sea conditions.Similarly fishing gear design has a major role in determining the energy efficiency of a particular fishing systems.

As per CMFRI (2012) there are 35,228 trawlers in the country of size ranging from 9m-30 m and engine power 45 to 495 hp. Trawl size ranges from 25-106m with 12-14 mm φ PP rope used as head and foot ropes weight of the otter board ranging from 60-110kg Along with the introduction of larger vessels with high power engine large mesh trawls were also introduced for speed trawling and the mesh size in the wing went up to 10m. Along with increase in vessel size and engine power, the size of the trawls also increased proportionately and many of these trawlers practise multiday operations.

When the vessel size and engine power increased to equip them for multiday voyages the size of trawl net also increased which led to the increase in fuel consumption and operation expenditure of trawling.

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Table 1. Profile of fuel consumption of mechanized trawlers in Kerala (Sayana, 2018)

Fuel use Small

trawlers (single

day)

Small trawlers

(multiday)

Medium trawlers

Large trawlers

Very large trawlers

Consumption per hour

6.12-8.75 (7.5)

15.3-18.9 (17.3)

17-23 (20.45)

26.7-32.3 (30.1)

43.86-52.8 (48.5)

Consumption per day

46-70 (60)

138-170 (155.71)

190-244 (225.0)

320.66-387.73

(361.07)

526.37-633.62

(582.27) Consumption per trip

- 414-510 (467)

948.5-1219.5 (1125)

3207-3877 (3610)

6735-7345 (6987)

Consumption per year

11760-12312

(12036)

34095-36085 (35090.3)

46287-60243

(54722.0)

86438-97675

(90285)

140589-153246

(146732.5) Trawl Drag

In trawling system vessel drag is the primary factor determining the fuel efficiency. In bottom trawling reduction of drag of the trawl net is identified as one of the most important factor for achieving fuel efficiency. Drag is the power required to overcome thehydrodynamic resistance of the towed gear at a particular speed. Estimation of drag can be done through model studies or using actual gear orcan be estimated theoretically (Hameed & Boopendranath, 2000).Estimation of drag of commercial trawls in Kerala reveals that it ranges from 1.37 to 48.94 kN (Sayana, 2018). Factor determining drag of trawl system

Drag of a trawl system depends the quantity of webbing, otterboards, ground gear (bobbins and foot rope), number floats, sinkers, length of warp, bridles and other operational parameters. Accordingly warp contribute 5%, sweeps 4%, otterboards 20%, floats 3%, foot rope 10% and netting 58% to the total drag of a trawl (Wileman (1984).Tauti (1934) assumed that drag force is proportional to the square of the water velocity.

Drag depends on many factors such as design of trawl net, rigging, operating conditions such as nature of water currents (against or along current direction), depth of operation, type and length of warp, etc. Apart from the design netting material used,netting construction properties (braided or twisted),the knot factor (knotted and knotless netting); net design (sequence of tapers) andtrawl spread ratio.

Trawl drag can be reduced by reducing the size of trawl, making less opening in wing end spread and head line height, reducing twine surface area, reducing ground contact friction or using more efficient otterboards. Material of fabrication of webbing has significant effect on

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resistance, efficiency and selectivity of gears. Ward et al. (2005) suggested material and twine diameter as the measures need to be reduced to improve energy efficiency and the use of knotless netting

Fig.1. Drag of components of a trawl gear

Steps to reduce drag of trawl nets

No Factors Reduction in

drag (%) 1 Operate multi-rig trawls 25-30 2 Use thinner twine 7 3 Use large meshes 7 4 Use knotless netting 7 5 Use curved otter boards (OBs) 4 6 Use optimal angle of attack for OBs 4 7 Use slotted OBs 2

(Wilman, 1984, and others)

Increasing the mesh size,reducing the twine thickness and twine surface area are supposed to reduce the drag offered by gear underwater. UHMWPE is a netting material which isstronger and thinner and with very low elasticity (Hansen &TØrring, 2012).

Similarly mesh orientation and mesh shape can also play an important role in reducingtrawl drag.Mesh orientation also helps to reduce the drag. Square mesh, T40 and T90 mesh will facilitate better mesh opening and water filtration and eliminate juveniles from the trawl apart from reduction in drag.Reduction in size of net, wing end spread, headline height are

other steps suggested for drag reduction in trawls.

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Fig. 2. Diamond mesh and T90 mesh

During calm weather conditions, major share of fuel is used to overcome the trawl drag compared to vessel propulsion intrawlers. In trawling operation, a sizeable time is spent for towing the gear and10-20% fuel consumed is spent to overcome the resistance (drag) during towing time. Hence it is understood that gear has a large effect on fuelconsumption during towing because drag due to vessel is insignificant at thetime of towing when compared to drag due to gear (Boopendranath, 2002).

Drag experienced in otterboards can be reduced by lifting them away from the bottom. CIFT- off bottom trawls use high aspect ratio otter boards and operate 0.5 -1.5m above sea bottom to reduce bottom impact and drag. Slotted otterboards also reduced drag as it allow the water to pass through the slots. Experiment with CIFT-double slotted boards showed better performance of the gear with less engine RPM as a result of drag reduction.

Fig. 3. Double slotted otter board Low Drag Trawls developed at ICAR-CIFT UHMWPE trawls

ICAR-Central Institute of Fisheries Technology (ICAR-CIFT) designed and fabricated low drag trawls for fish shrimp of head rope length 24.47 m 30.0 m respectively (Remesan, et al.2019).The drag reduction measures included in the design are increased mesh size and new material. The material used is ultra high molecular weight polyethylene (UHMWPE). As UHMWPE provides same strength with thinner twines, it would result in reduced twine area. For evaluation of new designs, trawl nets using conventional material, high density polyethylene (HDPE) is also fabricated and used as control. The experiments for evaluating the new design were conducted

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onboard M. V. Matsyakumari II. Data regarding dragand fuel consumption experienced for each operation were recorded using Warp Tension meter and Fuel flow meter fitted to the fuel line of the vessel. The depth of operation ranged from 10 to 20 m, the fishing speed was 3 to 4 kn and the warp length varied from 40 to 100 m

GigasenseTMWarp Tension Meter of 20 ton capacity was used to measure the drag acting on the towing warp. From the trials conducted, the average reduction in drag of new design is estimated to be 17%.

Fig. 4. Warp Tension Meteronboard MK-II

The average fuel consumption per one hour of trawling for HDPE trawls is estimated to be 30 litres and for UHMWPE trawls 26 litres. The average reduction in fuel consumption found to be 10%. The fuel consumption per kilogram of fish captured was also estimated and it is 2.9 litres for HDPE trawls and 1.9 litres for UHMWPE trawls and the average reduction is estimated to be 35%.

Fig. 5. Design of low drag shrimp trawl

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Fig. 6. Low drag shrimp trawl trialsonboard MK-II

Fig. 7. Dr.Trilochan Mohapatra, Secretary DARE and DG, ICAR, releasing the LDT system

technology onboard CIFT RV. SagarHarita

Cutaway top belly shrimp trawl

Modifying designs of trawl will help reduce drag as well as bycatch and discards. The cutaway shrimp trawlis a good example for that, which was designed based on the behavioural difference between fish and shrimp when encounter with the trawl. Shrimps roll along the bottom panel of the trawl when moving to the codend, whereas fishes actively swim up in the funnel and try to escape from the trawl. To reduce the drag the square and front portion of belly is removed and the net has long wings. The fishes can escape from the trawl mouth unhurt by clearing the head line.

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Fig. 8. Cutaway trawl used in Gulf of Maine pink shrimp fishery (source: He et al., 2007) Short body shrimp trawl to reduce drag

CIFT has developed and successfully field tested a 27 m shrimp trawl with relatively short

body and large horizontal spread suitable for selective retention of shrimp. The width and length of the trawl funnel has been reduced by increasing the tapering ratio and the vertical opening of the mouth has been reduced to eliminate bycatch. Because of the larger horizontal spread of the mouth the effective sweep area is more, which is the most vital requirement for a shrimp trawl.

Trials carried out along the coastal waters off Cochin with a prototype of short body

shrimp trawl reveals considerable reduction in the catch fish due to the behavioral difference of the targeted species.

The results indicates that there was a significant reduction in the drag. Mmean catch per unit effort (CPUE kg.h-1) of non-targeted fin fishes (from 9.75 kg.h-1 to 2.75 kg.h-1) and bycatch generated for capturing per unit weight of shrimp (3.5 and 1.69 respectively for the commercial and short body trawl). The Ecological Use Efficiency (EUE) by Alverson and Hughes (1996) was used to see the ecological impact of bottom trawling and it was noticed that the EUE was 0.22 and 0.37 respectively for catches in the commercial and short body trawls indicating a better efficiency for the short body trawls.

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Fig. 9. Short body shrimp trawl CIFT-Off Bottom Trawl

The system consists of a four panel trawl with double bridles, front weights and vertically cambered high aspect ratio otter boards of 85 kg each (Fig. 1).It is capable of attaining catch rates beyond 200 kg.h-1 in moderately productive grounds and selectively harvest fast swimming demersal and semi-pelagic finfishes and cephalopods, which are generally beyond the reach of conventional bottom trawls.

Fig. 10. High aspect ratio otter boards

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Advantages

• Significantly high sheer-drag ratio of vertically cambered high aspect ratio otter boards, makes

the system energy-efficient, compared to conventional flat rectangular and V-form otter

boards. The vertically cambered high aspect ratio otter boards have dual-purpose capabilities

and can also be deployed for conventional bottom trawling.

• Bottom impact of semi-pelagic trawl system is significantly lower, making it an ecologically

friendly gear, compared to bottom trawls.

• CIFT OBTS has shown significant resource specificity for off-bottom (semi-pelagic) finfishes,

which are generally large in size, fast swimming and exhibit shoaling characteristics

• Conventional bottom shrimp and fish trawls have low vertical opening, mostly limited to 1-1.5

m and hence their catches are limited to species living close to the bottom. Due to higher

vertical opening up to 4.0 m realized in CIFT OBTS, resources that are beyond reach of

conventional bottom trawls, could be efficiently harvested.

Fig. 11. CIFT-Off bottom trawl system

CIFT OBTS is indigenously developed and is best suited to Indian fishing conditions and fishery resources. The gear system has been developed and optimized taking into consideration ofbiological, behavioural and distribution characteristics of tropical demersal and semi-pelagic finfish and cephalopod resources and technical capabilities of the small-scale mechanized trawler fleet, operating in Indian waters.

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Fig.12. Off-bottom trawls trials onboard MK-II References/suggested reading CIFT (2011) CIFT SPTS: Eco-friendly Semi-pelagic Trawl System for Small-scale Mechanized Sector, Central

Institute of Fisheries Technology, Cochin

He, P., Doethel, D and Smith, T (2007) Design and test of a topless shrimp trawl to reduce pelagic fish bycatch in the Gulf of marine pink shrimp fishery. Journal of Northwest Atlantic Fishery Science 38:13-21DOI: 10.2960/J.v38.m591

Madhu, V.R, Remesan, M.P, Pravin, P and Boopendranath, M.R (2015). Cutaway top belly trawl-A new eco-friendly shrimp trawl design. In Book of Abstracts.p39. World Ocean Science Congress

Remesan, M.P., Madhu, V.R., Sayana, K.A., PrabeeshKumar, M.V.,Harikrishnan, K.R. and Edwin, L. (2017). Fuel saving throughmaterial substitution in trawls. Fish Tech Reporter 3(1):3-5

Remesan, M.P., Madhu, V.R., Sayana, K.A and Leela Edwin (2019) Low drag trawl for energy efficient fishing. Fishery Technology

Sayana, K.A., Ramesan, M.P., Madhu,V.R., Pravin, P. and Edwin, L. (2016) Appraisal of trawl design operated along Kerala coast. Fish. Technol. 53: 30-36

Sayana, K. A. Remesan, M. P Leela Edwin. (2018) Impact of operational parameters on drag of trawl nets. Fish. Technol. 55(4): 295 – 297

Sayana, K.A. Proliferating growth and fuel consumption of mechanised trawlers of Keralaand investigations on efficiency of low drag trawl. PhD Thesis. CUSAT 273p

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Bycatch Reduction Devices for Trawls V. R. Madhu

ICAR-Central Institute of Fisheries Technology, Matsyapuri, Willingdon Island, Cochin - 682029


Introduction

The global fish production reached the all-time high in 2016, estimated at 171 million tonnes, with the capture fishery contributing 90.9 million tonnes and the rest from aquaculture. With this high recorded production, the world fish supply reached a record high of 20.3 kg per capita in 2016. The record growth has been due to the increase in aquaculture production, whereas the global marine fisheries production has reached a plateau during the last decade and is now hovering around 80 million tonnes. It is estimated that about 33.1% of assessed fish stocks are overfished and the stocks which were fished at biologically sustainable levels decreased from 90 percent in 1974 to 66.9 percent in 2015 (SOFIA, 2018), and the percentage of assessed stocks that are underfished is estimated now as only 7%. The trends are really ominous and unless measures to ensure sustainability are not considered, there is no further potential for increase in marine capture.

Though there are different dimensions to the problem of stagnation in marine fish capture, growth overfishing and recruitment overfishing, illegal methods and gears used for fishing is a big issue. The non-legal gears used are often with smaller mesh sizes and are not regionally appropriate, which results in the capture of large amounts of non-targeted catch. Among the different fishing methods, however, trawling is implicated the most, due to generation of large quantities of bycatch and collateral damage to the ecosystem structure and function. Adding to the complexity is the exponential increase in the number of trawlers in the tropics over the years.

The importance of reducing bycatch and minimizing ecological impacts of fishing operations has been emphasized by scientists and fishery managers and recognized by fishermen. Trawl fisheries in different parts of the world are now required to use bycatch reduction devices as result of legal regimes introduced by the governments. The Code of Conduct for Responsible Fisheries (CCRF) (FAO, 1995), which gives guidelines for sustainable development of fisheries, stresses the need for developing selective fishing gears in order to conserve resources, protect non-targeted resources and endangered species.

Bycatch from harvesting systems

The term bycatch refers to the non-targeted species retained, sold or discarded for any reason. Target catch is the species that is primarily sought after in the fishery and incidental catches is the retained catch of non-targeted species and the discarded catch is that portion of the catch that is returned to the sea due to economic, legal or personal considerations. Global bycatch by the world’s marine fishing fleets was estimated at 28.7 million t in 1994, of which 27.0 million t (range: 17.9-39.5 million t) were discarded annually and shrimp trawling alone accounted for 9.5 million t (35%) of discards annually. In 1998, FAO estimated a global discard level of 20 million t. Average annual global discards, has been re-estimated to be 7.3 million t, based on a weighted discard rate of 8%, during 1992-2001 period (Kelleher, 2004). Davies et al. (2009) redefined bycatch as the catch that is either unused or unmanaged and re-estimated it at 38.5

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million tonnes, forming 40.4% of global marine catches. The recent global estimates of bycatch are 9.1 million tonnes, with highest contribution from bottom trawls of about 4.2 million tonnes, in which tropical shrimp trawl fisheries contributes the most. Based on confidential interviews, grey literature reports and direct field observations, during 2008-09, Pramod (2010) estimated the bycatch discards from mechanised trawlers operating in Indian EEZ at 1.2 million tonnes.

The reduction in bycatch discards globally, in recent years could be attributed to (i)

increased use of bycatch reduction technologies, (ii) anti-discard regulations and improved enforcement of regulatory measures, and (iii) increased bycatch utilization for human consumption or as animal feed, due to improved processing technologies and expanding market opportunities. Also equally important as the issue of bycatch is the un-quantified impacts of different fishing systems on the ecosystem, with active fishing gears like trawls causing the most damage. FAO has brought out International guidelines on bycatch management and reduction of discards, in view of its importance in responsible fisheries (FAO, 2011). Life under water (14th Goal) among the Sustainable Development Goal (SDG) has different targets for sustainable use of fisheries resources.

A typical trawl catch from the tropics typically consists of more than 25-35 species of different sizes and shapes, behavioural differences, different maturity sizes and longevities. The mesh size of the trawl codend used in shrimp trawls operating along the Indian coast varies from 10-20 mm, which makes it impossible for juveniles of other species to escape. for moreTrawl bycatch, in the tropics is constituted by high proportion of juveniles and sub-adults, particularly of commercially important fishes, which needs serious attention in development, optimization and adoption of Bycatch Reduction Technologies (BRD).

Fig. 1. Estimates of average bycatch discards from mechanized trawlers (Pramod, 2010)

Bycatch Reduction Devices

Devices developed to reduce the capture of non-targeted species during trawling are collectively known as Bycatch Reduction Devices (BRDs). These devices have been developed taking into consideration variation in the size, and differential behaviour pattern of shrimp and other animals inside the net. Different types of bycatch reduction technologies have been

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13.20

4.44

0.69

0 500 1000 1500 2000

Total

Kerala

Tamil Nadu

Andhra Pradesh

Karnataka

Orissa

Maharashtra

Andaman & Nicobar Islands

West Bengal

Gujarat

Average discards, x103 t

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developed in the fishing industry around the world (Prado, 1993; Brewer et al., 1998; 2006; Eayrs et al., 1997; Broadhurst, 2000; CIFT, 2007; Eayrs, 2007; Boopendranath, 2007; 2009; 2012; Boopendranath et al., 2008; 2010a; 2010b; Kennelly, 2007; Broeg, 2008; Boopendranath & Pravin, 2009; Pravin et al., 2011; Suuronen et al., 2012).

BRDs can be broadly classified into three categories based on the type of materials used

for their construction, viz., Soft BRDs, Hard BRDs, and Combination BRDs. Soft BRDs make use of soft materials like netting and rope frames for separating and excluding bycatch. Hard BRDs are those, which use hard or semi-flexible grids and structures for separating and excluding bycatch. Combination BRDs use more than one BRD, usually hard BRD in combination with soft BRD, integrated into a single system. Designs that reduce the non-targeted catch either by taking into account the behavioural difference of the species or by excluding the catch entered also can be considered as BRDs, though the term is commonly used for devices that are attached to trawls to reduce non-targeted catch.

Use of BRDs is one of the widely used approaches to reduce bycatch in shrimp trawls.

Some of the advantages in reducing the amount of unwanted bycatch caught in shrimp trawls by using BRDs are (i) Reduction in impact of trawling on non-targeted marine resources, (ii) Reduction in damage to shrimps due to absence of large animals in codend, (iii) Shorter sorting times, (iv) Longer tow times, and (v) Lower fuel costs due to reduced net drag (Boopendranath et al., 2008; Boopendranath & Pravin, 2009). The effects of BRD installation on total drag of the trawl system and hence on fuel consumption has been reported to be negligible (Boopendranath et al., 2008).

Soft Bycatch Reduction Devices

The soft Bycatch Reduction Devices use soft structures made of netting and rope frames instead of rigid grids, prevalent in hard BRDs, for separating and excluding bycatch. Based on the structure and principles of operation they are classified into five categories viz., (i) Escape windows, (ii) Radial Escapement Section without Funnel, (iii) Radial Escapement Section with Funnel, (iv) BRDs with differently shaped slits and (v) BRDs with guiding/separator panel. Soft BRDs have advantages such as ease of handling, low weight, simplicity in construction and low cost, compared to hard BRDs.

Hard Bycatch Reduction Devices

Various designs of hard BRDs are in operation around the world which includes (i) Oval grids, oval shaped metallic grid with exit opening like Georgia-Jumper, Saunders grid , Thai Turtle Free Device (TTFD),Oregon grate, CIFT-TED ,Seal Excluder Device and Halibut Excluder Grate; (ii) Slotted grid BRDs which provide slots for the passage of non-targeted organisms such as Hinged grid and Anthony Weedless; (iii) Bent grids in which grid bars and grid frame are bent at one end near the opening such as Juvenile and Trash Excluder Device (JTED), NAFTED; (iv) Flat grid BRDs such as Nordmore grid, Wicks TED, Kelly-Girourard grid, and EX-it grid.

Fisheye BRD is considered as an important hard BRD around the world. There are several

design variations of fisheye BRD such as Florida Fish Eye (FFE) used in the Southeast US Atlantic

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and in the Gulf of Mexico. Other designs in this categories are Snake-eye BRD used in North Carolina Bay, Fish slot, Sea eagle BRD and Popeye Fish excluder or Fishbox BRD.

Hard BRDs also include TEDs like NMFS hooped TED, Fixed angle TED and Cameron TED

(Oravetz and Grant, 1986; Prado, 1993; Mitchell et al., 1995; Talavera, 1997, Rogers et al., 1997), Matagorda TED, Georgia-Jumper, Super Shooter, Anthony Weedless, Jones TED and Flounder TED (Talavera, 1997; Mitchell et al., 1995; Dawson, 2000; Belcher et al., 2001; CIFT, 2003) that are devices used for the conservation of Sea turtles. Semi-flexible BRDs

Semi-flexible BRDs made of semi-flexible or flexible materials such as polyethylene, polyamide and FRP are used in the North Sea brown shrimp fishery, Polyamide grid devices provided with hinges to facilitates operation from net drums have been used in the Danish experiments in the North Sea shrimp fishery and Polyamide-rubber grid design are used in Denmark. BRDs with guiding or separator panel

Guiding or separator panels are used to achieve separation of the bycatch by using differences in their behaviour or size. BRDs with guiding panels lead the fishes to escape openings, making use of the herding effect of the netting panels on finfishes. The shrimps are not subjected to herding effect and hence pass through the meshes towards the codend. BRDs with separator panels physically separate the catch according to the size, with the use of appropriate mesh size. Shrimps pass through the panels to the codend while bycatch such as fishes and sea turtles are directed towards the exit opening Fig. (2).

Fig. 2 Separator panel BRDs

BRDs in India

A number of BRDs have been developed and field tested in India. The BRDs evaluated include hard BRDs viz., Rectangular Grid BRD, Oval Grid BRD, Fisheye BRD and Juvenile Bycatch Excluder cum Shrimp Sorting Device (JFE-SSD) and soft BRDs viz., Radial Escapement Device (RED), Sieve net BRD, Separator Panel BRD and Bigeye BRD (Boopendranath et al., 2008). The square mesh codend and JFE-SSD are the designs that were tested commercially along Indian waters. The efficacy of square mesh codends for selective fishing is widely reported in India and the selection parameters for a large number of fishes are derived (Madhu, 2018). The mesh lumen (opening) of the traditional diamond meshes used in codends, tend to close during fishing due to

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various forces acting on the net, whereas the square meshes remain open and retain their shape, thus allowing non-targeted catch like small fish and juveniles to escape through the mesh openings. Square mesh codends are prepared from diamond mesh webbing by barcuts, rejoining and then strengthening by marling to prevent the unravelling of the meshes. The conceptual simplicity and the ease of installation of square mesh codends made its adoption much easier in the trawl sector of India.

Table 1. Bycatch exclusion and shrimp loss in different BRDs, during shrimp trawling operations off southwest coast of India (Boopendranath, et al., 2012)

BRDs Bycatch exclusion, %

Shrimp loss, %

Bigeye BRD 11.4-37.3 2.3-4.1

Fisheye BRD 46.6-62.7 0.8-3.8

Oval grid BRD 57.8-58.7 6.1-8.0

Sieve net BRD 14.7 4.5

JFE-SSD 42.9 5.2

Fig. 3. View of the Bigeye BRD attached to the trawl codend. The opening of the BRD is kept open using floats.

Fig. 4. Perspective view of Sieve net BRD installed in trawlnet

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A large number of studies using square mesh codends in India, have demonstrated the

improvements in the selection properties (Boopendranath and Pravin, 2005; Madhu, 2018) and use of square mesh codends significantly reduces the bycatch often comprising of the juveniles of commercially important species. Studies carried out by ICAR-CIFT along the Indian coast have recorded an increase of 12-25% in the mean selection length of different targeted species. Good filtration and reduction in the drag are other benefits of the technology. It has also been demonstrated along Gujarat and Maharashtra using commercial operations that no significant economic losses are incurred if traditional meshes are replaced, since the escapees are the juveniles that fetch a low price in the market. This loss, though very meager is compensated with the fuel saved because of reduced drag of the trawl and improved quality of catch in the codend. The conversion of the traditionally used diamond meshes to square meshes is easy without involving additional cost.

Fig. 5. Square and diamond shaped HDPE webbing

Insertion of square mesh panels in the traditional codends are also found to improve the

selection properties in addition to reducing bycatch in trawls. An increase in the L50 values by 5-10% and a reduction in the bycatch by 4-5% were observed in case of square mesh panels field tested along Cochin coast. The advantage of the technology is the minimal amount of change required to the existing codend and minimal investment required for the installation.

Juvenile Fish Excluder Cum shrimp sorting Device (JFE-SSD) is another BRD that has undergone several commercial trials along Kerala, Gujarat and Maharashtra coast. JFE-SSD is a Smart Gear (WWF) award winning design developed by Central Institute of Fisheries Technology (CIFT) which reduces bycatch of juveniles and small sized non-targeted species in shrimp trawl and at the same time enables fishers to harvest and retain large commercially valuable finfishes and shrimp species. JFE-SSD operations off southwest coast of India have realized bycatch reduction up to 42.9% with shrimp retention of about 95%. Non-shrimp resources are largely guided to the top codend, with about 70% caught in the upper codend of the BRD. This BRD can be used as an alternate codend replacing the existing codends of trawlers for effective segregation of shrimp and fish and concomitant savings in terms of fuel and good catch quality.

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Fig. 6. Design of the JFE-SSD

Improved trawl designs like the CIFT-Off Bottom Trawls System (CIFT-OBTS), short body shrimp trawl, Cut-away Trawl belly and separator trawls are found to significantly reduce non-targeted catches due to its design features, though no BRDs as such are attached to the designs.

CIFT-Off Bottom Trawls System (CIFT-OBTS) consists of an 18 m four-panel semi-pelagic

trawl with double bridles, front weights and vertically cambered high aspect ratio otterboards as was developed as an alternative to traditional shrimp trawling in the Indian waters. Due to the design features, the net operates a few centimeters above the sea bottom and hence the bottom impact of the net decreased substantially. This is an ideal gear to operate during non-shrimping season, where fishers predominantly target the off-bottom species.

Short body shrimp trawl is a design variation with a relatively short body and large

horizontal spread for selective retention of shrimp. The length of the trawl body is reduced by increasing the taper ratio. The large horizontal spread of the trawl mouth increases the effective sweep area and the low vertical opening of the trawl and the short belly reduces the fish catch making the gear more selective for shrimps. The net has been designed considering the difference in relative swimming speed and vertical distribution of the shrimp and fish species occurring in the Indian waters.

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Fig. 7. Finfishes escaping from the short body shrimp trawl due to better swimming speed

(Artist perspective)

Conclusion

Studies using bycatch reduction devices have shown to reduce the incidence of bycatch in trawling considerably. Different BRD designs have been tried and the efficacy of a particular design depends on the composition of bycatch in the area. Experimental trials for optimization are needed before the designs are released for field trials among the fishers for adoption. A small loss in revenue, as a result of reduced bycatch is often negated when the overall future gain is considered in the fishery as a result of increase in the yield per recruit from the stock. Benefits like subsidies in the fishery can also be linked with the adoption of good practices in the trawl fishery. Use of BRDs for resource conservation is one of the many strategies for sustainable harvest of the fishery resources. Adherence to the norms in the marine fisheries regulations acts (MFRA), reduction of fishing effort (in terms of capacity and size of the vessels and gear), spatial and temporal fishing area restrictions and strict monitoring, control and surveillance are required for the gear based technical measures like BRDs to be effective. References/suggested reading

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Rogers, D.R., Rogers, B.D., Desilva, J.A., Wright, V.L., and Watson, J.W. (1997) Evaluation of shrimp trawls equipped with bycatch reduction devices in inshore waters of Louisiana. Fish. Res. 33, 55-72

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Talavera, R.V. (1997) Dispositivos excluidores de tortugas marinas, FAO Documento Technico de Pesca, No. 372, Roma, FAO. 116 p

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Fishing Technology interventions for sea Turtle conservation R. Raghu Prakash

Central Institute of Fisheries Technology, Visakhapatnam


Sea turtles are endangered species which are protected under schedule I of the Indian wildlife protection act 1972 and its amendment in 1991. Sea Turtles are listed as critically endangered or threatened on world conservation Union Red list. Sea turtles interact with trawl gears, pelagic long line gear on the high seas, and beach seine, gillnet and shrimp trawl gears in coastal waters. These interactions can lead to death, most frequently through drowning, when the turtles cannot climb to the surface of the ocean to breathe after becoming hooked or entangled in the fishing gear. New types of gear or ways of fishing can significantly reduce the rate of interactions between turtles and gear or the mortality rate after an interaction has already occurred.

The code of conduct of responsible fisheries (FAO 1995) gives guidelines for sustainable development of fisheries, prescribes the need for protecting endangered species like sea turtles. As a signatory to the code, India is bound to conduct research, develop appropriate devices and practices and implement regulatory measures for protection of endangered turtles. The fundamental objective of responsible fishing is to maximise economic returns to the fishermen without affecting the long term sustainability of fishery resources and with minimum impact of ecosystem

Trawling and sea turtle interactions

Trawling is considered to be a very effective method of fishing for demersal population in terms of investment and yield. Trawl nets are towed gears consisting of funnel shaped body of netting closed by a bag or cod end extended sideways in front to form wings. Trawling targets at mainly shrimps gained popularity over the years and led to the development of an organised fishing industry. Trawlers form nearly 80 % of the small scale mechanised fleet in India. Even though bottom trawl is an efficient fishing method for targeting demersal resources, it is less a selective fishing technique. Along with the targeted resources a large number of non target resources which include protected and endangered species such as sea turtles are also caught during trawling. Rajagopalan et al. (1996) reported that trawls accounted for 17.8% of the incidental catch along the Indian coasts. Along the east coast this problem has been aggravated due to rapid expansion of the mechanised fishing industry. Incidental mortalities of turtles is highest in Orrisa due to presence of large congregations of marine turtles.

An US law ( section 609 of of public law nos 101 -162) introduced in May 1996 restricted imports of shrimp harvested with fishing equipment such as trawls nets not equipped with Turtle excluder devices (TEDs). The subsequent shrimp turtle case brought environmental requirements in the WTO into the mainstream, through its interpretation of relevant WTO articles. In view of these concerns, with respect to trade and the environment, the Department of Animal Husbandry and Dairying, Ministry of Agriculture, Govt of India constituted an expert panel

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to conduct detailed investigations on marine turtle distribution in Indian waters, their incidental mortality in fishing nets and use of TED in trawl nets.

TED For Indian Fisheries

The Turtle excluder devices consist of panels of large mesh nettings (soft TED)or a frame consisting of a grid deflector bars (hard TED), installed before the cod end of the trawl net at an angle leading upward or downward into an escape opening. Small animals such as shrimp slip through the mesh lumen of the netting panel or gap between the deflector bars and are retained in the while large fishes and elasmobranchs are stopped by the netting or the grid of the deflector bars and can escape through the opening (Fig 1). Thus air – breathing marine turtles were prevented from capture and subsequent death after prolonged entrapment in the trawl.

Different designs of TED are available today and they vary with regard to their construction, principle of operation and materials for construction depending on the target groups and fishing conditions (Fig 2). Soft TED and Hard TEDs are the two types that are used worldwide (Mitchell et al 1995, Anon 2002a). The hard TED is rigid frame device installed ahead of the cod end to separatety and exclude turtles from the trawl catch. Designs of hard Ted include Gorgia Jumper, NMFS hooped TED, Fixed angle TED, Antony Weedless, Flounder TED, Super Shooter (Watson and Taylor 1988), Cameron TED, Jones TED, Thai turtle free device.

Modifications of the basic TED design have been carried out by different nations. Thai

Turtle free device was developed by Kasetsart University and SEAFDEC/TD, in Thailand (chokensanguan et al 1996, Chokesanguan 2000). The AusTED (Australlian trawling efficiency device) was developed in Australia (Mounsey et al 1995, Ribon-Troeger and Dedge 1995, Brewer et al 1998, Robins- Troeger and McGilvray 1999, McGilvray et al 1999) and CIFT –TED in Inda (Dawson 2001, Dawson and Boopendranath 2001, 2002a,b, 2003).

Fig. 1. Principle of TED operation

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CIFT was closely associated with evaluation of Super shooter TED designs of US origin. as envisaged under the mandate of expert scientific panel along with CIFNET with the support of MPEDA and FSI. Results of The experiments conducted by CIFT to evaluate the Super Shooter TED imported by MPEDA on Matsya Shikari has been detailed. The Shooter TED was of 1030 x 850 mm size with a deflector bar gap of 90 mm.

6 Fishing operations were conducted off Andhra, off Kalingapatnam at a depth of 45 – 55 m. The catch retained in the cod end comprised of catfish, perchs, pomret, seer and carangids. No turtle was retained in the experiment.

Experiments continued along the Bheemili and Chilka with a additional exit hole cod end provided at the exit hole to retain the catch excluded due to the installation of TED in the trawl net (Fig 3). During the 5 operations which was done at a depth of 45 -140 m a total of 676 kg was landed of which 469 kgs was retained in the main cod end. The results indicated an overall escapement of 30.8 % fin fish. Turtles were not retained in the main cod end or exit hole covered cod end (Ramarao, 1995a)

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During the operations off Andhra Pradesh using Super shooter TED on board MV Skipper

in the depth range of 36 -50 m (Kirubakaran et al 2002) two turtles were excluded during the operation. The TED operations with Exit hole at the top of the net resulted in a catch loss of 13.7 %, while operations with exit hole at the bottom resulted in a catch loss of 43.3%. (Kirubakaran et al. 2002).

Unlike fishers in USA, Australia and other advanced maritime nations, fishers on the

Indian coast target both shrimp and non-shrimp resources. Experiments with TED designs which have a deflector gap of less than 90 mm in Indian waters, though successful in excluding turtles showed poor performance in retention of targeted non shrimp catch components. Hence these TEDs are not considered suitable for Indian conditions, nor were they acceptable to Indian trawler owners and operators (Mishera and Behara 2001).

Development of CIFT-TED

An Indigenous design of TED was developed at CIFT with a focus on reducing by catch loss. THE CIFT-TED is a simple single grid hard TED with a top opening. The device can be fabricated and installed with minimum training using locally available infrastructure and net making skills at a cost of approximately Rs. 2500. The design, construction, installation and operation of CIFT-Ted have been elaborated by Dawson & Boopendranath (2002) (fig 4 -8). Field trials and demonstration with CIFT-TED along the east coast of India

A Total of 25 field trials were conducted with CIFT TED yielding a Total catch of 889.8 kg. (Table 1) The mean catch rate in operations with a CIFT-TED installed in trawl was determined to be 35.5 kg.haul -1. The catch composed of fin fishes Prawns, Cephalopods, Crabs, Sharks, Jellyfish. The predominant fin fishes included Pomfrets, Mackeral, Upenoids, Perches, Ribbon fish, Catfish, Bombay duck, Squilla, Silver bellies Soles, Puffer fish, Sciaenids, clupeids. Relative exclusion and retention rates during CIFT-TED installed operations along the east coast of India is given in Fig. 9. The catch loss due to CIFT TED installation was estimated to be 3.3 % for non shrimp resources. Out of a total of 26.8 kgs of shrimp landed only 0.5 % was observed to have been excluded after the installation of CIFT TED.

Fig. 3. Details of rigging of exit hole cod end for experimental operations

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Fig 4-8 Method of installation of the TED

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Table 1. Details of TED installed trawl operations along east coast coast

Area No of hauls

No of hours

Catch retained(kg)

Catch loss(kg)

Catch loss (%)

Paradeep (Orissa) 7 7 422.6 14.3 3.3 Dhamara (Orissa) 1 1 79.23 0.07 0.08 Astrang (Orissa) 1 1 50 0.05 0.1 Bahabalpur (Orissa) 1 1 22 0.3 1.36

Balaramagad (Orissa)

1 1 44 0.8 1.81

Visakhapatnam (A.P) 5 5 69 0.13 0.18

Kakinada (A.P) 6 6 133 1.8 1.35 Nizampatnam (A.P) 2 2 35 0.25 0.71

Krishnapatnam (A.P) 1 1 25 0.7 2.8

Vadarevu (A.P) 10 0.2 2 Total 25 25 889.83 18.6 2.09

Fig. 9. Relative exclusion and retention rates during CIFT-TED installed operations along the east coast of India

catch

escapes

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Longlining and sea turtle interactions

Incidental mortalities of sea turtles in pelagic long lining , a fishing method intended to catch migratory top predator fish, primarily tuna and swordfish is a global conservation concern. Scientists, managers and fishermen are working co-operatively to develop mitigation measures to reduce this mortality. Assessment of turtle avoidance measures in longline fishery contributes to a small but growing body of research. Research on methods to avoid sea turtles in pelagic long line fisheries has been initiated only recently. Most experiments had small sample sizes and had been conducted over only a few seasons in a small number of fisheries (Gilman et al., 2006a).

catches escapes

Fig. 10. Relative exclusion rates of different species groups after installation of CIFT-TED durng experimental trawling along east coast of India

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Further-more, few studies considered effects of turtle avoidance methods on other bycatch species, including seabirds (Gilman et al., 2005), sharks (Gilman et al., 2007) and cetaceans (Gilman et al., 2006c).

Hook Design

Most turtles are either hooked as they attempt to eat the bait or are entangled in the line. Changes in hook design and bait type were a few as measures to reduce the bycatch of sea turtles on pelagic longlines. Studies have showed that Use of large circle hooks with no greater than a 10 degree offset, combined with whole fish bait have been effective in reducing sea turtle mortality in longline fishing . Circle hooks reduce turtle mortality because the size and shape of the hooks makes it more difficult for the turtles to swallow, avoiding damage to internal organs.

These hooks are typically wider than the traditional hooks J hooks and have barbs pointed back towards the shaft of the hook, making ingestion more difficult. Therefore even the sea turtle being caught by the circle hook, hooking position will be around its jaw and the hook can be easily removed. Circle hooks are currently being tested in many fisheries and have been proposed by fishery managers as a practical and economical measure to reduce sea turtle mortality in pelagic longline fisheries. Specifically, the effectiveness of 18/0 circle hooks has been evaluated with respect to reducing sea turtle interactions and maintaining swordfish and tuna catch rates. Individually, circle hooks and mackerel bait significantly reduced both loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtle bycatch (Watson at al 2005).

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Setting longlines

Longline set depths can be critical to incidental sea turtle mortality. The depth at which

longline gear are set and the length of leaders for individual hook lines from the main line affect both the takes and mortality of sea turtles. Arrangement of gear configuration and setting of the line such that the hooks remain active only at depths beyond the range of sea turtle interaction would reduce sea turtle mortalities. Shallower sets of longline gear are more likely to result in interactions between the turtles and the gear, since turtles are more likely to swim higher in the water column. Longer leaders can reduce sea turtle mortality. In addition after hooking, by pelagic gear, line cutters can reduce sea turtle mortality by allowing the turtle to swim away rather than bringing the turtle onboard. Retrieval of longline gear earlier in the day and reducing soak time of hooks is also suggested.

Purse seine fishing and sea turtle interaction

Sea turtles are occasionally caught in purse seines in the tuna fishery. Most interactions occur when the turtles associate with floating objects (for the most part fish-aggregating devices (FADs), and are captured when the object is encircled; in other cases, the net, set around an unassociated school of tunas or a school associated with dolphins, may capture sea turtles that happen to be in the location. In these latter cases, the presence of tunas and turtles together may be influenced by oceanographic features such as fronts, but is essentially a chance event because turtles cannot swim fast enough to travel with tunas or dolphins. Once captured, the turtles may be released unharmed, injured, or dead. They can drown if they are entangled for a prolonged time and are unable to reach the surface to breathe. The actions to reduce sea turtle mortality in purse seines include :-

• Avoid encirclement of sea turtles to the extent practical.

• If encircled or entangled, take all possible measures to safely release sea turtles.

• For fish aggregating devices (FADs) that may entangle sea turtles, take necessary

measures to monitor FADs and release entangled sea turtles, and recover these

FADs when not in use.

• Conduct research and development of modified FADs to reduce and eliminate

entanglement.

• Implementation of successful methodologies developed.

Gillnets and sea turtle interaction

Gill net fishery is the man stray of the traditional sector along the Indian coast. In Andhra Pradesh about 7,12,362 gillnets and 4,013 drift gillnets are being operated. (CMFRI census, 2002) Turtles become entangled in artisanal gill nets set inshore close to the nesting beaches and on the path of the sea turtle migration. On the high seas they get caught in massive drift nets. Rajagopalan (2001) reported that gillnets accounted for 76.8 percent of turtles landed or trapped along the Indian coast. Therefore the crucial factor to be considered in planing conservation measures is the livelihood of coastal fishers.

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The following are gear-technology approaches that have been shown to significantly reduce sea turtle catch rates in individual gillnet fisheries:

• Reducing net profile (vertical height; Eckert et al. 2008).

• Increasing tiedown length, or eliminating tiedowns (Price and Van Salisbury 2007).

• Placing shark-shaped silhouettes adjacent to the net (Wang et al. 2009);

• Illuminating portions of the net using green lightsticks (Wang et al. 2009).

In demersal gillnet fisheries, use of narrower (lower profile) nets is an effective and economically viable method for reducing sea turtle by-catch rates due to the combined effect of: The net being stiffer, thereby reducing the entanglement rate of turtles that encounter the gear, as sea turtles that do interact with the gear to ‘‘bounce out’’ and free themselves more readily than with conventional gear and the net being shorter, thereby reducing the proportion of the water column that is fished and so reducing the likelihood of turtles encountering the fishing gear.

Increasing tiedown length, or avoiding the use of tiedowns, has also help decrease turtle entanglement rates in demersal gillnets . In demersal gillnet fisheries, tiedowns are typically used to maximize the catch of demersal fish species. Tiedowns are lines that are shorter than the fishing height of the net and connect the float and lead lines at regular intervals along the entire length of the net. This net design creates a bag of slack webbing which aids in ‘‘entangling,’’ rather than ‘‘gilling,’’ demersal fish species. The shorter the length of tiedowns, the deeper

the webbing pocket is. Unfortunately, this technique also poses an entanglement hazard to sea turtles that encounter the gear. Several studies in North Carolina’s flounder (Paralichthys lethostigma) gillnet fishery found that lower profile nets without tiedowns resulted in a significantly lower incidence of seaturtle entanglement, compared with traditional gillnets containing twice as much webbing (twice the number of meshes) and containing tiedowns regularly placed throughout the gear (Price and Van Salisbury 2007). Research has also demonstrated that entangled turtles have a higher rate of escape when longer tiedowns are used (Gearhart and Price 2003).

Illuminating nets with green lightsticks attached to the net can reduce green sea turtle by-catch rates without adversely affecting the catch rate of target species when compared to control nets without illumination research in a Mexico demersal gillnet fishery ( Wang et al. 2009).

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Incorporating a shark shape was also found to result in a significant reduction in sea turtle catch rates; however, this resulted in a large and significant reduction in the target species catch rate (Wang et al. 2009)

Aspects of gear design, materials and methods that affect turtle survivorship after interaction with gear is also limited. This information is fundamental to guiding further research and development of gear-technology approaches to by-catch. Mitigation. Unfortunately Technological interventions in this case is scarce. Therefore a dynamic spatial temporal restriction seems may be an alternative since turtles show a preference to specified area and seasons for migration and nesting. Once vulnerable areas are identifies, it should be possible to evolve and adopt suitable measures with active participation of the community. Research on the turtle mortality in relation to type of gillnet, depth of operation and time of operation would help in evolving a framework for conservation measures. Fisheries management guidelines for fisheries activities and conservation and management of sea turtles.

FAO 2003 prepared to Guidelines offer guidance to the preparation of national or multilateral fisheries management activities and other measures allowing for the conservation and management of sea turtles. They apply to those marine areas and fisheries where interactions between fishing operations and sea turtles occur or are suspected to occur. They are global in scope but in their implementation national, subregional and regional diversity, including cultural and socio-economic differences, should be taken into account.

Fishing operations

Appropriate handling and release.

(i) In order to reduce injury and improve chances of survival:

(ii) Requirements for appropriate handling, including resuscitation or prompt release of

all bycaught or incidentally caught (hooked or entangled) sea turtles.

(iii) Retention and use of necessary equipment for appropriate release of bycaught or

incidentally caught sea turtles.

Coastal trawl

(i) In coastal shrimp trawl fisheries, promote the use of turtle excluder devices (TEDs) or

other measures that are comparable in effectiveness in reducing sea turtle bycatch or

incidental catch and mortality.

(ii) In other coastal trawl fisheries, collect data to identify sea turtle interactions and

conduct where needed research on possible measures to reduce sea turtle bycatch or

incidental catch and mortality.

(iii) Implementation of successful methodologies developed.

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Purse seine

(i) Avoid encirclement of sea turtles to the extent practical.

(ii) If encircled or entangled, take all possible measures to safely release sea turtles.

(iii) For fish aggregating devices (FADs) that may entangle sea turtles, take necessary

measures to monitor FADs and release entangled sea turtles, and recover these FADs

when not in use.

(iv) Conduct research and development of modified FADs to reduce and eliminate

entanglement.

(v) Implementation of successful methodologies developed

Longline

(i) Development and implementation of appropriate combinations of hook design, type

of bait, depth, gear specifications

(ii) Fishing practices in order to minimize bycatch or incidental catch and mortality of sea

turtles.

Other Fishery management stategies

(i) Spatial and temporal control of fishing, especially in locations and during periods of

high concentration of sea turtles.

(ii) Effort management control especially if this is required for the conservation and

management of target species or group of target species.

(iii) Development and implementation, to the extent possible, of net retention and

recycling schemes to minimize the disposal of fishing gear and marine debris at sea,

and to facilitate its retrieval where possible.

Research, monitoring and sharing of information Collection of information and data, and research

(i) Collection of data and information on sea turtle interactions in all fisheries, directly or

through relevant RFBs, regional sea turtle arrangements or other mechanisms.

(ii) Development of observer programmes in the fisheries that may have impacts on sea

turtles where such programs are economically and practically feasible. In some cases

financial and technical support might be required.

(iii) Joint research with other states and/or the FAO and relevant RFBs.

(iv) Research on survival possibilities of released sea turtles and on areas and periods

with high incidental catches.

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(v) Research on socio-economic impacts of sea turtle conservation and management

measures on fishers and fisheries industries and ways to improve communication.

(vi) Use of traditional knowledge of fishing communities about sea turtle conservation and management.

Information exchange

(i) Sharing and dissemination of data and research results, directly or through relevant

RFBs, regional sea turtle arrangements or other mechanisms.

(ii) Cooperation to standardize data collection and research methodology, such as fishing

gear and effort terminology, database development, estimation of sea turtle

interaction rates, and time and area classification.

(i) C. Review of the effectiveness of measures

(i) Continuous assessment of the effectiveness of measures taken in accordance with

these guidelines.

(ii) Review of the implementation and improvement of measures stipulated above.

Ensuring policy consistency

A. Maintaining consistency in management and conservation policy at national level, among

relevant government agencies, including through inter-agency consultations, as well as at

regional level.

B. Maintaining consistency and seeking harmonization of sea turtle management and

conservation-related legislation at national, sub-regional and regional level.

Education and training

A. Preparation and distribution of information materials such as brochures, manuals, pamphlets and laminated instruction cards.

B. Organization of seminars for fishers and fisheries industries on:

A. Nature of the sea turtle-fishery interaction problem

B. Need to take mitigation measures

C. Sea turtles species identification

D. Appropriate handling and treatment of bycaught or incidentally caught sea turtles

E. Equipment to facilitate rapid and safe release

F. Impacts of their operations on sea turtles

G. Degree to which the measures that are requested or required to adopt will contribute

to the conservation, management and recovery of sea turtle population.

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H. Impacts of mitigation measures on profitability and success of fishing operations

I. Appropriate disposal of used fishing gear

C. Promotion of awareness of the general public of sea turtle conservation and management

issues, by government as well as other organizations

Capacity building

A. Financial and technical support for implementation of these guidelines in developing

countries.

B. Cooperation in research activities such as on status of sea turtle incidental catch in coastal

and high seas fisheries and research at foraging, mating and nesting areas.

C. Establishment of a voluntary support fund.

D. Facilitation of technology transfer.

Socio-economic and cultural considerations

A. Taking into account :

(i) socio-economic aspects in implementing sea turtle conservation and management

measures.

(ii) cultural aspects of sea turtles interactions in fisheries as well as integration of cultural

norms in sea turtle conservation and management efforts.

(iii) sea turtle conservation and management benefits to fishing and coastal communities,

with particular reference to small-scale and artisanal fisheries.

B. Promotion of the active participation and, where possible, cooperation and engagement of fishing industries, fishing communities and other affected stakeholders. C. Giving sufficient importance to participatory research and building upon indigenous and traditional knowledge of fisherfolk C. Giving sufficient importance to participatory research and building upon indigenous and traditional knowledge of fisherfolk These modifications in fishing methods significantly help in reducing the capture rate of sea turtles and potentially the post fishing mortality of those that were caught and did not negatively impact the primary target species catch. These mitigation measures have the potential to reduce mortality of sea turtles and other bycatch species worldwide. Better understanding of the links between sea turtles and fishing allows the design of conservation initiatives that reduce their interactions and thereby sea turtle mortality. Better understanding of these links leads, in part, to designing fishing gear, and adopting management practices and methods of fishing that reduce the takes and mortality of sea turtles.

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References/Suggested reading

Andrew J. (2006) Do circle hooks reduce the mortality of sea turtles in pelagic longlines? A review of recent experiments Biological conservation vol. 135, pp. 155- 167

Anonymous. 2000 Study on the distribution of sea turtles, their incidental mortalities in fishing nets and use of turtle excluder device in fishing trawlers. Submited to the Ministry of Agriculture, Govt of India

Anonymous. 2002a. Electronic code of federal regulations 50 CFR wildlife and fisheries chapter II Sub chapter C: Marine mammals part 223 – Threatened marine species. National Marine fisheries Service, National Oceanic and atmospheric Administration, Dept. of Commerce, USA. http://www.access.gpo.gov/ecfr

Anonymous. 2002b Workshop cum demonstration on turtle excluder device for trawl owners and operators of Orissa, 9 – 12 February 2002, Orissa: A report

Brewer D, N Rawlinson, S Eayrs and C Burrige. 1998 An assessment of Bycatch eduction devices in tropical Australian prawn fishery. Fishery Research 36: 195 -215

Choksanguan, B 2000. Introduction of TEDs in Asia. In proceedings of International expert consultation on sustainable fishing technologies and practices 1-6 March 1998, St John’s Newfoundland, Canada, ed. A R Smith and J W Valdemarsen. FAO Fish Rep. No 588, Suppliment 153 -173

Choksanguan, B, Y Theparoonrat, S Ananpongskuk, S Sirriraksophon, L Podapol, P Aosomboon and A Ahmed 1996. The experiment on Turtle Excluder device (TEDs) for shrimp trawl nets in Thailand. SEAFDEC Technical Report TD/SP/19. 43

Dawson, P, and M R Boopendranath 2002b Application of CIFT for Turtle conservation. In Proceedings of the workshop on operation of Turtle excluder Device (TED) 24 -25 January 2002, Kakinada, Dept. of Fisheries. Govt. of Andhra Pradesh

Dawson, P, and M R Boopendranath 2002b. CIFT-TED: Construction, installation and operation CIFT Technology Advisory Series 5 CIFT Kochi 16 pp

Dawson, P, and M R Boopendranath 2003. CIFT-TED: Construction, installation and operation . kachhapa 8: 5-7

Gilman, E., Dalzell, P., Martin, S., 2006 b. Efficacy and Commercial Viability of Regulations Designed to Reduce Sea Turtle Interactions in the Hawaii-Based Longline Swordfish Fishery. Western Pacific Regional Fishery Management Council, Honolulu, HI, USA. ISBN 1-934061-02-6.30 (4), 360–366

Gilman, E., Zollett, E., Beverly, S., Nakano, H., Shiode, D., Davis, K., Dalzell, P., Kinan, I., 2006a. Reducing sea turtle bycatch in pelagic longline gear. Fish and Fisheries 7 (1), 2–23

Kirubakaran, P, M Neelakandan, S Shaji, D V Rao, N Venkateshwarlu and V Selvearaj. 1989 . On the mortality and stranding of marine mammals and turtles at Gahirmatha, Orrisa from 1983 to 1987. J of Marine Biol. Assoc. of India 31 ( 1 & 2): 28 – 38

McGilvray, J G, R P Mounsey and J MacCartie 1999. The AusTEd II : An Improved efficiency device 1. Design Theories. Fisheries Research 40: 17 -27

Mishra , R S and C R Behera. 2001 Need for indigenising the turtle excluder deice for Indian waters. In proceedings of the National Workshop for development of National sea tutle conservation action plan, Bhubaeshwar orisa April 2001. Ed k. Sankar and B C Choudary Wildlfe institute of India 12 – 14

Mitchell J F, J W Watson, D. G Foster and R E Caylor. 1995. The turtle excluder device ( TED) A guide to better performance. NOAA Technical Memorandum NMFS-SEFSC – 366 35 pp

Rajagopalan, M.E Vivekanandan, K Balan and K N Kurup 2001. Threats to sea turtles in India trough incidental catch. In proceedings of the National Workshop for the development of national sea turtle conservation action plan, Bhubhaneshwar, Orrisa, April 2001, ed K. Sanker and B C Choudary. Wildlife institute of India 12 – 14

Ramarao, S V S 1995a. Tour report on operation of turtle excluder device from FSI vessel 16 – 25 August 1995 CIFT Kochi

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Ramarao, S V S 1995a. Tour report on operation of turtle excluder device from FSI vessel 20 – 30 September 1995. CIFT Kochi

Robins- Troeger J B and Drege 1995. Dvelpment of trawl efficiency device( TED) for Australian prawn fisheries. II Feld evaluations of AusTED. Fisheries Research 22: 107 – 117

Robins-Troeger J B and J G AcGlvray, 1999. The AusTED II, an improved trawl efficiency device. 2. Commercial performance. Fisheries Research 40: 29 – 41

Watson, John W.,Epperly, Sheryan P.; Shah, Arvind K.; Foster, Daniel G 2005. Fishing methods to reduce sea turtle mortality associated with pelagic longlines . Canadian Journal of Fisheries and Aquatic Sciences, Volume 62, Number 5, 1 May , pp. 965-981(17)

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Surrounding nets and seines: structure, operation and conservation aspects

Leela Edwin ICAR-Central Institute of Fisheries Technology, Kochi


Introduction

Surrounding nets are large netting walls set for surrounding aggregated fish both from the sides and from underneath, thus preventing them from escaping by diving downwards. Apart from a few exceptions, surrounding nets are surface nets. The netting wall is framed by lines: a float line on top and lead line at the bottom (FAO, 2019).The netting is designed to maintain a wall-like shape when being set. A float line supports the net at the top, while a lead line ensures the bottom of the net sinks to create a wall-like structure. The general operating principle of a surrounding net is the same regardless of net size or the number of vessels used. When a school of fish is located, one end of the net is anchored to a surface buoy or a small skiff while the main vessel sets (puts out) the rest of the net in a large circle around the targeted school of fish, returning to the initial spot of deployment. The surrounding nets are mainly employed to catch the shoaling pelagic fishes. The pelagic fishes are adverse group of small to large fishes which occupy mainly the surface and column layers of the water mass. Most of them are characterized by their shoaling behavior eg. Sardines, mackerel, tuna etc. The catching offish shoal is by the mechanism of surrounding the shoal. The fish shoal is identified by their behaviour in the water column, colour variation and very few by sound. Hence the modern nets are equipped with the fish shoal identifying devices such as sonar, echo sounder etc. Globally tuna fishery by surrounding nets are a popular one at industrial scale. Visual spotting of the shoal is the major task in the use of surrounding net and crow’s nest is a specialized area in these vessels to monitor the fish shoals. Surrounding nets

Surround net fishing is an ancient fishing method recorded in historical records, in which the purse seines were used as early as 200 years ago, and the modern purse seining started evolving 100 years ago. Surrounding nets or round haul nets are long wall of webbing that surround a school of fish from below as well as from sides to prevent their escape. Surrounding nets are classified as below.

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Purse seining is one of the most efficient advanced fishing methods, and by virtue of its

efficiency relatively few vessels are required to harvest the suitable resources exploited by the purse seines. Historically and technologically, purse seines and ring nets have developed from beach seine and lampara fishing methods. Beach seines are inshore dragnets consisting of long wall of netting which are usually deeper than the depth of the water. The Mediterranean origin of the lampara is widely recognized and some ancient Egyptian pictures describe fishing with nets which have a lampara or boat seine shape. In contrast to beach seines, lampara are true surround net have short wings, a deep central bunt and a lead line substantially shorter than the float line. Ring seine is one of the most commonly used gear, hybrids between the purse seines and lampara nets. The ring seines are used in two boat, small scale inshore fishing operations. Two boat ring seining enables small boats and even non-mechanized boats and canoes to use relatively large nets. Ring seines represent a level of purse seining technology which may be very appropriate to small –scale fishermen of the world. Purse seine

Purse seine is made of a long wall of netting framed with float line and lead line have purse rings hanging from the lower edge of the gear, through which runs a purse line made from steel wire or rope which allow the pursing of the net (FAO, 2019). Purse seine is used to capture of dense, mobile schools of small pelagic fishes. The principle of catching fish in a purse seine involves surrounding a school of fish by a long wall of webbing and subsequently pulling the bottom of the net by means of a purse line. The fish catch from this artificial pond of webbing is then removed either by brailing or pumping, small purse seines can be operated entirely by hand.

Fig. 1. A typical purse seiner of Kerala

Along the Indian coast, purse seine operation is confined to the west coast. A total of 1,213 purse seiners operate in India. The purse seiners operated along coastal states of India are concentrated in Maharashtra (435), Karnataka (422), Goa (294) and Kerala (60) (CMFRI, 2012). Purse seine contribute 22.7%, 82% and 20.3 % of the marine landings of Maharashtra, Goa and Karnataka respectively during 2012-13 (CMFRI, 2013). The purse seiners in India are mainly made of wood and steel and their size ranges from 11 to 23 m LOA. They are equipped with marine diesel engines with power range of 110 to 420 hp. Purse seines are operated from single vessel and skiff assists the fishing operation. Purse seiners generally undertake single day fishing in

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Kerala and Karnataka whereas purse seiners from Goa carry out multi-day fishing. Electronic equipments like GPS, echosounder, VHF receiver are mainly used for vessel navigation, fish detection and communication. Mobiles are also used to communicate fishing areas, grounds, catch etc. The crew complement varies from 25 - 35.

Purse seines mainly target fishes like mackerel, sardine, white bait, carangid, tuna, barracuda, seer fish, cat fish, wolf herring, pomfret, lizard fish and croaker. The head rope length of purse seines ranged from 450 to 1500 m and depth of netting range from 60 to 100 m. Purse seines are made of polyamide multifilament webbing with mesh size range from 18 to 46mm. Some vessels carry two purse seines (18 mm and 46 mm mesh size) on board. In artisanal or semi-industrial fisheries, the purse seine handling equipment may include: a purse seine winch, a purse line reel, a brailer and a power block and in some fisheries, a net drum. In industrial purse seine fishery, the basic equipment include : a hydraulic power block, a powerful purse seine winch, a number of derricks, including a brailer or a fish pump, and small winches, an auxiliary boat "skiff" and sometimes, an helicopter. The purse seine can be used by a large range of vessel sizes, ranging from open boats and canoes up to large ocean going vessels. The purse seines can be operated by one or two boats. Most usual is a purse seine operated by a single boat, purse seiner, with or without an auxiliary skiff.

Fig. 2. Purse seine

Source: http://www.fao.org/fishery/geartype/249/en Structure of purse seine

Bunt is a main region of the purse seine where the catch is accumulated and it is made up of thicker twine. The bunt portion is placed in the centre or at the end of the wall of the netting depending on the type of operation. Main body is the largest part of the net extends from one end to the other end of the net except the bunt region and facilitates surrounding of the fish shoal during operations. It is made by joining together large sections of webbing of appropriate mesh sizes to catch the target fish. The material used should have high specific gravity to increase the sinking speed during setting. The lighter type of twisted knotless netting are used for purse seines. Knotted webbing is preferred to compare with knotless webbing because of the damage portion of knotted webbing can be repaired. Selvedges or guarding are strips of strong netting used for strengthening the main webbing to protect it from damage during the time of operation. It is provided in the upper, lower and side edges of the main body of the net. The upper selvedge is attached to the float line (head rope) and the lower selvedge to the lead line (foot rope) and also attached to the side ropes or gavel lines.

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Fig. 3. Structure of typical purse seine

The total buoyancy of float is maintained at 1.5 to 3.5 times the total under water weight

of the purse seine net by using cylindrical or spindle shaped floats. Higher buoyancy is provided in the bunt area for counteract the sinking force due to weight of heavier netting in this area. Spindle shaped sinkers are attached to the lead line. Purse rings are made up of steel or brass rings are used with snap type or closed. The size of purse rings depends on the size and weight of the net. For small and light purse seines, purse rings (100 mm -150 mm) made of steel 10 mm in diameter and weighting 1 to 1.5 kg each can be used. For bigger nets rings of 120 mm to 180 mm across of steel 12 mm in diameter and weighing 2 kg to 3 kg each can be used. Tow lines are made up of rope or steel wire and is the last part of the seine. The end of the tow line remains attached to the seiner. It is used to allow a greater circumference of set to be made by using the tow line as an extension of the net.

Factors to be considered in the design of purse seines

The size of the vessel, biological characteristics of the target species and characteristics of

the fishing area are considered during the design process. The length, depth and shape of the net depend on the target species. Selection of materials, mesh size and twine thickness for the bunt, body netting, hanging coefficient, determination of weight and floats required for the net are other design parameters for purse seines.

Length and depth of the seine are determined by the size of the vessel, the species,

behaviour of the fish and fishing conditions. Depth is between 10 and 15% of the length (BenYami, 1994) is easiest for purse seine operation. In certain cases, the depth goes up to 30-50% of the length in inshore purse seines for sardines, anchovies etc. where the shoal depth is generally high. The depth of the purse seine is more commonly one-tenth of the float line, but may vary from one fourth to one-third for deep swimming and quick diving shoals. The overall size of purse seine is best expressed as length of the float line. Purse seine in water is not a truly vertical wall of webbing but the net is hung so that it is roughly cup-shaped when laid out in a circle. This is accomplished by making the lead line shorter than the float line by 5 to12% (Ben-Yami, 1994).

The mesh size and twine size are directly related to the size of fish and the quantity of fish

caught. To select a small mesh size increases the cost and results in slow sinking. And large a

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mesh size results in loss of catch as well as gilling. The mesh size of purse seine must be small enough not to gill the fish in any part of the seine. To select a smaller mesh size in the bunt, compared to the body meshes. Choice of mesh size is a function of the target species and is estimated by the following formula (Fridman, 1986):

Mesh opening in the bunt (mm) = 2/3.LK

where L = length (mm) of target fish: K=5 for fish that are long and narrow; 3.5 for average shaped fish; 2.5 for flat, deep bodied or wide fish

The main criterion for determining the twine thickness for netting in a purse seine is to provide sufficient strength for pursuing and hauling when the load due to the fish is maximum. The wing ends and the lower and upper selvedges of the seine are subjected to the greatest stresses. Therefore twines of greater thickness are used in these parts. Minimal loads are imposed on the central section of the seine

Sinking speed is found to be proportional to the square root of the apparent lead line weight. Excessive weights results in damage, strain on hauling equipments and handling problems. The normal requirement is 0.5 top 2.0 kg. m of foot rope. The buoyancy requirement is 2-4 times of the weight of the foot rope. The weight of the ballast (in air) normally ranges between one-third and two-third of the weight of the netting in air. The weight in air of the ballast in the foot rope is generally between 1 and 3 kg /m and up to 8 kg/m in large tuna seines (Prado, 1990). The rigging of floats on a purse seine must take into account not only the buoyancy needed to balance the total weight of the gear in water, but also should have additional buoyancy. This additional buoyancy should be of the order of 30% for calm waters and up to 50-60 %% in areas of strong currents to compensate for rough sea conditions and other factors related to handling of the gear. Buoyancy should be greater in the area of the bunt and mid-way along the seine, where puling forces are greater during pursuing (Prado, 1990). In general, the buoyancy of the floats should be equal to about 1.5to 2 times the weight of the ballast along the bottom of the seine (Prado, 1990). Lead line of the purse seine is usually longer than the float line up to10 %. However, in some designs, the two lines are equal in length. Operation

Purse seining operations involves location of fishing grounds, scouting, setting, pursing and hauling. Searching for fish aggregation, then identifying wherever possible the fish species and evaluating school size and its catchability, prior to surrounding are important aspects of purse seine operation. In artisanal or semi-industrial fisheries, the purse seine handling equipment may include a purse seine winch or a capstan, a purse line reel, a brailer and a power block and in some fisheries, a net drum. In industrial purse seine fishery, the basic equipments include, in general, a hydraulic power block or Triplex roller, a powerful purse line winch, a number of derricks, including a brailer or a fish pump, a skiff and sometimes, a helicopter. The purse seine can be used by a large range of vessel sizes, ranging from open boats and canoes up to large ocean going vessels. The purse seines can be operated by one or two boats. Most common ones are those operated by a single boat, with or without an auxiliary skiff.

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Fig. 4. Power block used in purse seiners of Goa

Lampara nets

Lampara nets are a traditional Egyptian fishing gear and were widely used in the Nile Delta sardine fishery. The term lampara stems from the Greek and Latin roots of the word lamp (lampas, lampa), as this net must have been associated with fishing with light attraction for a long time in the Mediterranean. Lampara type nets are also used in other parts of the world. Examples of such nets are the Philippine sapyaw which looks like an almost wingless lampara, the Japanese nuikiri- ami,the Indian kolli net (Von Brandt, 1984) and the alaman of the Black Sea ( Ben- Yami, 1976). Structure of Lampara net

The lampara net is a surrounding net, shaped like a dust pan or a spoon (the lead line is much shorter than the float line) with two lateral wings and a central bunt with small meshes to retain the catch (FAO, 2019) without a pursing device. The mesh size varies in different parts. The wing part is made of netting with larger meshes than the centre of the net. The deep central bunt is in middle and hauling is done with both short wings. The ground rope is shorter than the head rope gives the lampara a scoop like shape especially while being hauled. The open front side is lifted after surrounding the fish shoal.

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Fig. 5. Lampara net

Source: http://www.fao.org/fishery/geartype/201/en Operation

The net is mostly used with a single vessel, like a boat seine operated by a single vessel. Once the shoal of fish has been surrounded, the two wings are hauled up at the same time. Lampara nets targets pelagic fish species. Lampara nets are mainly operated in the Mediterranean, in the USA and South Africa especially for sardines, in Argentina for anchoveta and mackerels or in Japan, not only for sardines, but also for sea bream and flying fish; sometimes in inland waters. The gear can only be used to catch fish close to the water surface. The principal impact produced by this category of nets may be occasional bycatch/discards, in particular when the lampara is used in association with aggregating devices (FAD).

Ring seine

Ring seines are hybrids between the purse seines and lampara nets. Ring seines are most

suitable for small scattered schools like anchovy, mackerel and sardines. They are lighter to handle, cheaper to build and faster in operation. The ring seines are effective in impounding small schools of fish in shallow waters up to 40 m depth from small low powered vessels. The ring seine or mini purse seine gear was first designed and introduced by the Central Institute of Fisheries Technology as a new gear for the traditional craft (Panicker et al., 1985). The mini- purse seine introduced had an overall length of 250m and a depth of 15m and 33m at the wing end and the bunt. Although it originated in Kerala this has spread to all states in the east and west coasts of India.

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Fig. 6. A typical Ring seiner of Kerala

Structure of a Ring seine

The structure of the ring seine has many features similar to the purse seine. The ring seine, like the purse seine, has purse rings along its lower edge. Some of the chief structural differences between the original ring seine and the purse seine are that the purse seine is made of comparatively heavy webbing, is practically uniform throughout its entire length, and is square on the ends; while the ring seine, is made of light webbing, is gathered on the ends. It was operated from a plank built canoe of 15 m length propelled by a 9.9 hp engine.

The gear is a wall of nylon knotless webbing and is mainly used to catch sardines, mackerel and small fishes like anchovy. The mini- purse seine introduced by CIFT, which is a modified innovative version of the thanguvala, on the other hand had an overall length of 250 m and a depth of 15 m and 33 m at the wing end and the bunt respectively and pursing was done with the help of rings (Panicker et al., 1985). The size of gear as reported by Edwin and Hridayanathan (1996) in south central Kerala region was 630m and depth 100 m with a mesh 18-20 mm. The ring seine of smaller mesh size (8 - 10 mm) is used to target small fish like anchovy and operate in shallow waters. The report by D’Cruz (1998) showed that the gear had grown in dimensions and due to the large size of the nets, trolleys are used for transportation of the gear. Large ring seines up to 900m length and 90 m depth were reported by Krishna et al. (2004) from Thrissur District of Kerala. Edwin et al. (2010) reported that for a gear with mesh size of 20 mm, length ranged from 600 to 1000 m, depth ranged from 83 to 100 m and weight ranged from 1500 to 2500 kg, which were operated from a fishing vessel of LOA 70-76 feet long powered by inboard engine and hold a crew of 35-45. In the past thirty years the size of the ring seines have grown at least three to four times in proportion to the extent of about 1000 m in length and 100m in depth in Cochin area Operation Ring seine is operated from a single boat or a pair of boats. The fishing unit leaves the landing centre at around 5 am. The fishing operation consists of active search, chase and interception of the shoal. One or two experienced fishermen standing at the aft of the craft is responsible for the detection of the shoals. Once the shoal is detected its direction of movement,

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direction of current, wind etc., are monitored to determine the mode of operation of the net. If the shoal movement and the water current are in same direction more area has to be encircled as quickly as possible in order to trap the fast moving fish. If the movement of shoal and water current are in opposite direction the chances for successful operations are high. After the shoal identification the crew leader signals for the preparation of shooting of net. After getting the signal one of the crew member (Chattakaran) jumps into the water holding one end of the net, the remaining net is carried by the boat around the fish shoal very fast and return to the initial point and usually encircling will take 8-12 minutes. After encircling the shoal, the purse line is pulled mechanically/manually which closes the bottom of the seine (Edwin and Das 2015).

Fig. 7. Design of 1000m Ring seine, Kerala

Pursing may take around 10 to 15 minutes. This is followed by hauling onboard the head rope and netting panels until it reach bunt portion. The entire net now looks like a bag and the fishes are concentrated at the bunt region. Large mechanized ring seiners use large scoop net called the “brailer” for transferring the catch onto the main vessel which is operated with the help of winch operated crane fixed on the deck at the aft part. In a two boat ring seiner one vessel searches for the shoal and on finding the shoal, this vessel signals to the main vessel to start operation by encircling the shoal. Encircling of the shoal is carried out by the valavallam and after this is done the two vessels together haul up the gear either mechanically or manually. Time taken to complete a haul varies from 30 minutes to 3 hours depending upon the size of the catch. Usually after the first catch fishermen will search for one more shoals and start the return trip. The boat usually reaches back at the landing centre by 2 pm. The average time taken for operation in mechanized units is around 12h and for motorized vessel is 8 h (Edwin and Das 2015).

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Fig. 8. Operation of Ring seine Traditional Seines

A seine is a type of surrounding gear which surrounds a certain area and then the gear is towed over this area with both ends to a fixed point either on the shore or vessel. Seines are aimed at catching shoals of fish either at the bottom or in midwater. Seines are broadly classified as beach seine and boat seine. Beach seine

Beach seine is operated from the beach by means of a boat laying the gear in a semi-circular form, consequent to which both ends of the hauling ropes are pulled simultaneously on to the beach. These are operated in shallow coasts of seas, lakes, rivers and reservoirs. The fishes caught mainly are sardine, mackerels and prawns. Structure of Beach seine

The gear consists of a long wall of webbing, the depth of which is reduced at the wing portion. Mesh size increases towards the wings. The bag made of thick twine, where the fishes

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finally get accumulated, is called bunt. The portion between the bunt and the wing is called shoulder. The net is towed by means of two hauling ropes. The length of beach seine varies between 150 and 2000 m, height 5-40 m and hauling lines between 150 and 6000 m.

Fig. 9. Structure of typical beach Seine

The net consists of three major sections: Warp/hauling rope, wing and the bunt/codend, to where the catch is concentrated. The region of the net where the catch is accumulated is called bunt. Bunt portion is made of 8 to 10 mm polyamide webbing. Total length of the bunt varied from 18-25 m in length. Bunt is placed in the center portion of the gear and made with heavier netting to withstand the excess strain during operation. Two wings extends from the lateral margins of the codend with a length of 500 – 800 m which herds the fish towards the codend. Small meshed webbing panels were attached near to the codend and gradually the mesh size increases towards the warp end. The wings taper towards the end where is connected to the hauling rope. Warp/hauling rope locally called as Kamba in Kerala which is the longest part of the gear with 1000 -1200 m in length as is used for hauling. Operation

Beach seines are most successfully operated in areas of smooth bottom and calm waters.

The entire process of shooting and hauling should be carried out as fast as possible for efficient operation. A large number of people (100-120) persons may be needed for operation of a beach seine. Hauling line of one wing is held by one of the parties on the shore while the boat steams in a semicircle from the shore paying out the bag, wing and hauling rope of the other side. This continues till the net is paid out completely and the boat returns to the shore. The two hauling lines along with wings are then pulled by two groups of fishermen bringing the catch on to the shore. The foot rope is hauled slightly faster than the head rope to prevent escape of fish. Operation of a beach seine

Twenty to forty fishers are involved in the fishing operations depending up on the season.

(Saleela, 2015). One group of fishermen will remain on shore holding one end of the hauling rope. The second group carrying the gear on a boat along with the other end of the hauling rope, which encircles the fish shoal/fishing area and set out in a wide semi-circular arc and brought the other end to the shore, which is a certain distance away from the starting point. The hauling ropes are

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then hauled simultaneously to the beach by two groups of fishers. The long hauling ropes and the wings of the beach seine herd fish into the centre part of the gear (Tietze, 2011). When the hauling starts, the two groups of fishermen will come closer (where codend almost reaches the shore) and the method of operation is common throughout the world. Beach seine is operated throughout the year and the peak season starts after monsoon in the south west coast. The maximum operational time for this gear is varied from one to three hours. The dominant groups of fishery includes Clupeidae dominated by Sardinella longiceps, Engraulidae (Stolephorus indicus), Scombridae (Rastrelliger kanagurta), Carangidae, Hemiramphidae, Sphyraenidae, Leiognathidae, Sillagnidae, shrimps etc.

Fig. 10. Beach Seine of Kerala

Boat seine

The boat seines consists basically of a conical netting body, two relatively long wings and a bag. An important component for the capture efficiency of boat seines is the long ropes extending from the wings, which are used to encircle a large area. Many seine nets are very similar in design to trawl nets. Frequently, however, the wings are longer than on trawls. The foot rope is usually a fairly heavy rope weighted with lead rings or hanging lead ropes. The seine ropes are made from synthetic fibre ropes with a lead core or from a combination of ropes.

In medium and large sized vessels special rope hauling (a small but fast winch) and

coiling machinery is installed on deck. The long ropes are often coiled in bins (on or below the deck) but on modern seiners these are stored on large hydraulic reels. For hauling the net hydraulically operated power blocks are used. In smaller boats seine nets are manually operated. Seine net boats range in size from relatively small 10 m up to about 30 m in length. Operation

The whole gear is encircling a large area in more or less a triangular pattern. The net is hauled back by the anchored boat, which is done by hauling the two drag lines simultaneously with the help of the winches, first relatively slowly and increasing to a larger hauling speed when the net is nearly closed. The use of an anchor is often referred to as Danish seining. Fish inside the

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ropes are frightened into the forward moving path of the seine net where they are subsequently overtaken by the net and captured. Another boat seine technique is similar, but is not using an anchor. Instead the boat is kept stationary during haul back with the propeller. This technique is often referred to as Scottish seining or Fly dragging. Mainly demersal and pelagic species are targeted by boat seine. Seine nets are operated both in inland and in marine waters. The catching area depends on the length of the ropes; catching depth is shallower than 50 m in lakes and down till 500 m in marine waters. The techniques is most efficient on flat and smooth bottom when long ropes (2 500 m) can be used. Boat seines are also used in rougher grounds, but then with shorter ropes. In some areas are boat seines used to catch schooling fish off the bottom. The impact on living resources are similar to that for trawls as small meshes in the codend may result in capture of undersized fish and sometimes non-target species.

Fig. 11. Operation of beach seine

Source: http://www.fao.org/fishery/geartype/203/en Resource and Energy Conservation in surrounding nets and seines

Selectivity studies of fishing gears around the world have focused mainly on trawls, gill

nets, hook and line and traps (Fridman, 1986; Mac Lennan, 1992). A few studies on the selectivity of seine nets have been conducted in South East Asia (Anon, 1995, Dickson, 1987 and Dickson 1995). The experience of the crew makes it possible to judiciously select the presence of juvenile and bycatch species. Bycatch species are commonly present in FAD- assisted purse seining and more than 40 species of fish and cetaceans have been reported from purse seine landings (Romanov, 2002; Pravin et al., 2008). Special escape panels known as Medina panels, which are sections of fine mesh that prevent dolphins from becoming entangled in the gear, and back down maneuver have been deployed to prevent capture of dolphins in purse seines (Ben-Yami, 1994). Selection of mesh size for the purse seine appropriate for the target species. Proper choice of fishing area, Depth and season could also lead to better selectivity of purse seines. Study conducted by Edwin and Hridayanathan (2003) shows that there is a likelihood of fish surviving if released from a purse seine than from a trawl net cod end, larger meshes and filter panels can be used to allow the unwanted fish to escape. The observations made during the study show that there exists a selection after pursing in the large mesh ring seines used on the Kerala coast.

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Juveniles are mainly caught in ring seine gears using 8-10mm mesh size and such units

are operated at shallow depths touching the bottom in inshore waters. Studies showed that the juvenile incidence in small meshed units is in the range of 32 - 48 % and that of large mesh unit is 5 - 12 %. According to CMFRI (2012) the year 2011 noticed a heavy exploitation of sardine young ones and juveniles and 78.5 % of the landings are contributed by seine net units. Fishermen gain some economic benefit from the juveniles, but the juvenile fish landing causes 65-75% income reduction and results in catch depletion. The reason for surrounding and catching the juvenile shoals as opined by fishers was that the returns from sale of juveniles would cover the operational costs and further there are no restrictions on the sale of juveniles in the market. The regulation of size and mesh size of seines as recommended by ICAR-CIFT is given below

Name of gear Minimum mesh size (mm)

Type of mesh Maximum dimension (hung length and hung depth)

Seine net Sardine/ Mackeral seine nets

22 Diamond 600 m x 60 m

Anchovy seine nets

10 Diamond 250 m x 50 m

The fleet size of ring seiners has increase drastically in India. It is observed that there has been a increase in the size of the gear with a commensurate increase in size of the fishing vessel and horsepower of the engine. The dimensions of the gear rose incrementally over the years and the size of the vessels and horsepower increased subsequently. In the past twenty eight years the size of the ring seines have grown at least three to four times in proportion to the extent of about 1000m in length and 100m in depth in Cochin area. In order to accommodate the huge gears the craft also increased two fold in size in these areas and number of craft forming a unit increased as many as four times. Currently mechanised ring seiners are powered by inboard marine diesel engines with power ranging between 98 to 550 hp. The Kerala Marine Fisheries Regulation Act amended through gazette notification, 2018 has stipulated the dimensions of the gear, mesh size and engine horse power of seines to be operated in Kerala.

The recommendations of engine horse power for purse seiners and ring seines by ICAR-

CIFT is as below

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Purse seining/ ring seining is one of the most fuel efficient techniques for catching shoaling pelagic fishes. Moreover this gear have no major damaging effects on the sea bed. The carbon emission for one kg of fish production in ring seine unit is 0.37 kg/kg of fish (CIFT, 2013). The fuel consumption for small scale mechanized purse seining was 0.07 kg fuel/kg fish(CIFT, 2008).

As beach and boat seines do targeted fishing, bycatch and discards are comparitively very low and in the developing countries traditional shore seines are listed as fisheries with low to negligible discard rates (Kelleher, 2005). Gear setting and soaking requires minimum time compared to gillnets or long lines and operation can be completed within 1- 3 h. In the construction of the gear, many natural biodegradable materials like coir, coconut leaves and natural fibres are still in use in countries like India. Technical and operational improvements for the reduction of juvenile catches in shore seine need to be developed which would support sustainability of beach seine fisheries.

Conclusion

Surrounding nets take advantage on shoaling behaviour of pelagic species and nets can catch a diverse group of small to large fishes which occupy mainly the surface and column layers of the water mass. Since seines are non selective gear care should be taken by boat operators in ensuring conservation of resources for long term sustainability. The dimensions of the gear have to be kept under check through regulation enforced by the respective governments to prevent over exploitation. The energy use in the seine sector has increased drastically especially in states like Kerala and results in consumption of excess fuel thereby increasing GHG emission. The size of fishing vessel and horse power of engine have to be regulated. In traditional seines the decreasing mesh size of the gear and the increasing size of the net are causes of concern. However, energy expenditure is relatively very low in the sector and therefore judicious use of the surrounding nets and seines can be allowed for exploitation of pelagic resources.

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References/suggested reading Anon (1995) Research in fishing technology in the Philippines, Bureau of Fisheries and Aquatic Resources.

Paper presented at the FAO workshop on research in selectivity of fishing gear and methods in the Southeast Asia and selective shrimp fishing. Chendring, Malaysia, 25th May, 1995

Ben- Yami, M. (1976) Fishing with Light, FAO Fishing Manual, Fishing News Books Ltd., Farnham: 121 p

Ben- Yami, M. (1994) Purse Seining Manual, FAO Fishing Manual, Fishing News Books Ltd., Farnham: 416 p

CMFRI, (2012) Marine Fishery Census 2010, CMFRI, 110p

CMFRI (2013) CMFRI Annual Report 2012-13, CMFRI

D’Cruz, T. S. 1998. The ring seine evolution and design specification, South Indian Federation of Fishermen Societies, Thiruvananthapuram, 47 pp

Dickson, J.O. (1987) Panguil Bay, Philippines- the cause of its over exploitation and suggestion for its rehabilitation. Paper presented at the Symposium on the exploitation and management of marine fishery resources in Southeast Asia held in conjunction with the twenty second session of the Indo Pacific communication, Darwin, Australia RAPA/REPORT: 1987/10: 218 – 234

Dickson, J.O. (1995) Bycatch of commercial fishing with surrounding nets in Philippines. Paper presented at the FAO Workshop on research in the selectivity of fishing gear and methods in the Southeast Asia and selection shrimp fishery, Chendring, Malaysia 15th May

Edwin, L. and Das, D.P.H. (2015) Technological Changes in Ring seine Fisheries of Kerala and Management Implications, Central Institute of Fisheries Technology, Cochin

Edwin, L. and Hridayanathan, C. 1996. Ring seines of south Kerala coast, Fish. Technol., 33(1): 1-5

Edwin, L., Nasser, M., Hakkim, V. I., Jinoy, V. G., Dhiju Das, P. H. and Boopendranath, M. R. 2010. Ring seine for the small pelagic fishery. In: Meenakumari, B., Boopendranath, M. R., Edwin, L., Sankar, T. V., Gopal, N. and Ninan, G. (Eds.), Coastal fisheries resources of india: conservation and sustainable utilization, Society of Fisheries Technologists (India), Kochi, p. 305-313.

FAO (2019) Fishing Gear types. Beach seines. Technology Fact Sheets. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 13 September 2001. [Cited 16 November 2019]. http://www.fao.org/fishery/FAO 2001-2019

FAO (2019) Fishing Gear types. Boat seines. Technology Fact Sheets. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 13 September 2001. [Cited 16 November 2019]. http://www.fao.org/fishery/

FAO (2019) Fishing Gear types. Surrounding Nets without Purse Lines. Technology Fact Sheets. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 13 September 2001. [Cited 16 November 2019]. http://www.fao.org/fishery/

Fridman, A.L. (1986) Calculations of Fishing Gear Designs, FAO Fishing Manual, Fishing News Books (Ltd). Farnham: 264 p

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Krishna, S., Gopal, N., Thomas, M., Unnithan, G. R., Edwin, L., Meenakumari, B. and Indu, K. A. 2004. An overview of fisheries during the trawl ban in Kerala - Part I. Technical bulletin, Central Institute of Fisheries Technology, Kochi, 15 p

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Meenakumari, B. ed., 2009. Handbook of fishing technology. Central Institute of Fisheries Technology

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Pravin, P., Meenakumari, B. and Boopendranath, M.R. (2008) Harvest technologies for tuna and tuna like fishes in Indian seas and bycatch issues, In: Harvest and Post-harvest Technology for Tuna (Joseph J., Boopendranath M.R., Sankar TV., Jeeva J.C. and Kumar A., Eds.), p. 79-103, Society of Fisheries Technologists (India), Cochin

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Saleela K. N., Dineshbabu A. P., Santhosh, B., Anil M. K., and Unnikrishnan C., (2015) J. Mar. Biol. Ass. India, 57 (2), July-December 2015

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Diversity of trawl catch in India Nenavath Rajendra Naik



Introduction The marine fish landing from the coast of the main land of India in 2017 was estimated as 3.83 million tonnes (t). The mechanised sector remained as the highest contributing sector with 3.17 million t (82.6%). In the mechanised sector 46.5% of the catch was by mechanised multi-day trawlers, 12.5% by mechanised single day trawlers, a total of 788 marine fish species were landed along the Indian coast (CMFRI, 2018). The region-wise breakup of the landings indicated that southwest and northwest contributed almost equally to the landings spectrum with 12.33 lakh tonnes and 12.32 lakh tonnes respectively whereas the southeast contributed 8.82 lakh tonnes and 4.88 lakh tonnes by northeast during 2017. Gujarat continued to be in the top position for the fifth consecutive year with 7.86 lakh tonnes. Tamil Nadu stood behind Gujarat with 6.55 lakh tonnes. Kerala has overtaken Karnataka to emerge as the third largest producer in 2017 (Fig.1) (CMFRI, 2018).

Fig. 1. State-wise fish production (lakh t) all along Indian coast

Marine Fisheries Pelagic finfishes dominated the marine fish landings during 2017 by contributing 54% of the landings. Indian oilsardine, mackerel, ribbon fish, lesser sardines and Bombay duck contributed almost 60% of the pelagic fish landings. Of this, oilsardine alone accounted for 16.3%.

0.00

2.00

4.00

6.00

8.00

Catch (lakh t)

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Demersal finfishes contributed 26.8% to total landings. The major demersal resources landed were threadfin breams, croakers, silver bellies, bullseyes (Priacanthus spp.), and catfishes. Crustaceans comprised high value resources like shrimps, crabs and lobsters and the contribution from this group was 12.6%. Molluscs comprising squids, cuttlefish, clams and oysters accounted for the remaining 6.6% (CMFRI, 2018). The mechanised sector remained the highest contributing sector with 3.17 million t (82.6%) being caught by this sector. The catch rates in terms of per boat catch was high (1568 kg/trip) for the mechanised sector. In terms of hours of operation also the catch rates were high for mechanised sector (50 kgh-1). In the mechanised sector, 46.5% of the catch was by mechanised multi-day trawlers, 12.5% by Mechanised single day trawlers (CMFRI, 2018).

Fig. 2. Marine fishery resources landings (%) along Indian coast

Table 1. Estimated marine fish landings (tonnes) in India 2017 Pelagic finfish Demersal finfish CLUPEOIDS ELASMOBRANCHS Wolf herring 18566 Sharks 19777 Oilsardine 337390 Skates/Guitarfish 2628 Other sardines 226970 Rays 17766 Hilsa shad 63437 Eels 13174 Other shads 6967 Catfishes 88177 ANCHOVIES Lizard Fishes 57803 Coilia 33574 PERCHES Setipinna 8777 Rock cods 53924 Stolephorus 64859 Snappers 10518 Thryssa 38003 Pig-face breams 16483 Other clupeids 67607 Threadfin breams 157773 Bombayduck 145115 Bullseyes 143451

Pelagic 54% Demersal

27%

Crustacean 13%

Mollusc 6%

Catch (%)

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Half Beaks&Full Beaks 7883 Other perches 53807 Flying Fishes 1345 Goatfishes 20306 Ribbon Fishes 239355 Threadfins 10764 CARANGIDS Croakers 150241 Horse Mackerel 51964 Silverbellies 89901 Scads 108010 Whitefish 3807 Leather-jackets 16237 POMFRETS Other carangids 120019 Black pomfret 12622 MACKERELS Silver pomfret 28789 Indian mackerel 287880 Chinese pomfret 5466 Other mackerels 636 FLAT FISHES SEER FISHES Halibut 2069 Scomberomorus commerson 30170 Flounders 90

Scomberomorus guttatus 18163 Soles 43173 Scomberomorus lineolatus 74 Shellfish Acanthocybium solandri 268 CRUSTACEANS TUNNIES Penaeid shrimp 209513 Euthynnus affinis 27680 Non-penaeid shrimp 202748 Auxis spp. 16640 Lobsters 2863 Katsuwonus pelamis 10559 Crabs 53476

Thunnus tonggol 7350 Stomatopods 14784 Thunnus albacares 13505 Cephalopods Other tunnies 4656 MOLLUSCS Bill Fishes 11328 Squids 131774 Barracudas 33337 Cuttlefish 109089 Mullets 7939 Octopus 10816 Unicorn Cod 325 Miscellaneous 2135 Miscellaneous 68279 TOTAL 3834574

(Source CMFRI, 2018)

Trawl fisheries

Trawling is the major gear used to exploit marine resources along Indian coast. Penaeid shrimps are the main stay of the trawl fishery. Out of 35,228 trawlers in the fishery, Gujarat accounted for the maximum (32.9%) followed by Tamil Nadu (16.4%), Maharashtra (15.9%) and Kerala (10.4%) (CMFRI, 2012)

Single day trawlers leave the fishing port early morning and return by afternoon. The multiday trawlers operate for more than one night extending up to 9 to 13 days. Though trawl is a non-selective gear there is a targeted fishery in each season. Major targets are shrimps, cephalopods and high valued demersal fishes. High opening bottom trawls, and midwater trawls are operated which target demersal, semipelagic and pelagic fishes. In the early years of trawling the depth of operation was limited to 30 to 50 m with the voyage time of 5 to 8 hours. The entire catch was brought to the shore and similar scenario is continuing in single day operating vessels

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in many landing centres. In the case of multi-day operating vessels generally entire catch was not brought to shore if the catch is more than the fish hold capacity. It was observed that the comparative economic viability of bringing the fish in preserved form or in non-preserved form depends on the demand for the species in the landing centre (Dineshbabu, 2014).

Average all India trawl landing for the period 2008-2011 was 17, 21,000 t with a maximum of 20,27, 000 t in 2011 which formed 51 % of the total marine fish landing in the country . The west coast of India contributed 51 % of the catch. Gujarat State accounted for 20% of the trawl landing of the country of which 42% is landed at Veraval fisheries harbor. Likewise, Karnataka account for 11% of the country’s trawl landing of which 54% landed in Mangalore fisheries harbor. On the east coast of India, Andhra Pradesh accounted for 9% of Indian trawl landing of which Visakhapatnam fisheries harbor accounted for 51%. It was observed that even though the total landing by trawlers showed a steady increase during 2008-2011, similar increase was not reflected in the edible portion of the landing, which was fluctuating around 3 lakh t. The nonedible portion of the landing steadily increased from 50,000 t in 2008 to one lakh t in 2011. The LVB at different centres increased from 16% of the total catch in 2008 to 27% in 2011 (Dineshbabu, 2014).

Trawl catch

The introduction of high opening bottom trawls has reduced the dependence of trawlers on shrimps as the chief revenue earner and cuttlefishes and squids have also emerged as principal income earners. The finfishes exploited by trawls belong to 21 major fish groups, out of which, sciaenids contributed maximum (18.4%) to the demersal landings along the Indian coast, followed by threadfin breams (17.3%). Each region is characterised by dominance of specific finfish groups. The NE coast is characterised by the dominance of sciaenids, catfish and pomfrets (together contributing 74% to the demersal landings), the SE coast is characterised by the dominance of silverbellies and pigface breams, the SW coast by the threadfin breams and other perches, and the NW coast by the sciaenids, catfish and threadfin breams (Zacharia, 2012). The total production by trawlers along the northeast sector of India was 2.39 lakh t, during 2014 (CMFRI, 2018). Goat fishes (23.7%) and silverbellies (23.1%) were dominant in trawl catch, followed by clupeids (9.85%), ribbonfishes (8.33%) and nemipterids along Southeast coast of India during 2004-6 (Sreedhar, 2010).

In Gujarat, the annual marine fish landings during 2017 registered an all time high of 786495 t. Sector-wise, Gujarat showed the dominance of mechanised fishing vessels with a catch of 7.38 lakh t. Landings from mechanised sector were mainly contributed by multiday trawlers (MDTN), where highest catch was landed from MDTN (4.04 lakh t) with 46 kg h-1 Catch per unit effort.

Estimated marine fish landings of Maharashtra during 2017 was 3.81 lakh t with 30%

increase from the previous year (2.92 lakh t). Trawlers contributed 57% of catch.

Total estimated marine fish landings in Karnataka and Goa was 547784 t and 61219 t respectively. Mechanised sector comprising mainly trawlers and purseseiners was the major contributor to the catch in both the states. Pelagic resources continued to be the dominant group in both states followed by the demersal fishes, crustaceans and molluscs.

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Total marine production in Tamil Nadu during 2017 was 6.55 lakh t. Single day mechanised trawlers contributed 56.5% of the total landings, followed by multiday trawlers (17.5%) and together formed 74% of the total landings. Total landing in Puducherry was 27040 t. MDTN contributed 74% of the total landings. Trawl landings in Andhra Pradesh was 1.36 lakh t forming 51.8% of the total marine landings during 2013-14. Marine landings of Andhra Pradesh in 2017 were estimated at 1.99 lakh t. Trawl was the major gear contributing 46.78% with catch rates of 22.06 kg h-1 for multiday trawlers and 8.34 kg h-1 for motorised outboard trawlers. Discarded bycatch

In 2008, the estimated discard constituted 18% of the total trawl catch at Mangalore, which came down to 6% in 2011, whereas in Calicut the discarded catch which was 15% of the total trawl catch came down to 4% in 2011. At Veraval, in most of the season, the entire bycatch was landed by trawlers, as there was no restriction of the landing of trash in any form of deterioration. In Visakhapatnam the discarded catch was 22%. In Mumbai 15% of the bycatch was presumed to be discarded since there was restriction on trash fish landing in deteriorated form and the average trash landing was only 7% of the total trawl landing. In Chennai, reported discard was very nominal (1%) (Dineshbabu, 2013).

Low value bycatch (LVB)

At Veraval, it is a regular trend to land most of the fishes caught by trawlers and the LVB landing during 2008-11 showed a steady increase from 24% to 33%. At Veraval fisheries harbor, a very efficient market chain exists for the LVB which encourages trawl operators to bring as much trash as possible for landing. During the year 2011, 10.44% of the catch was discarded at Veraval during the monsoon and post monsoon months (August to December), when the demand for the trash fish is loo low due to erratic weather conditions. The trash landing at Veraval was more than 50,000 t in 2011. In major landing centres of Mumbai, the percentage of LVB landed remained around 5%, and the trash fish landed were only those caught during the last day of the voyage.

In Mangalore, as in other centres, single-day trawlers brought all the catch to shore and

the trash consisted of 30 to 40% of total catch. On the other hand, multiday trawlers brought the trash in semi-preserved form suitable for fish meal and fertilizer producers. In Mangalore also a strong market chain exist for the LVB and the business is becoming a very prominent economic activity in fisheries of Karnataka. In Mangalore fisheries harbour the increase in trash landing was phenomenal, the trash landing which formed only 3 % (3,000 t) of the trawl landing in 2008 increased to 26% of the total fish landed (12,000t) in 2011, the percentage of LVB was 3, 14, 21, 26 in 2008, 2009, 2010 and 2011 respectively. This increase in LVB landing was the result of increased demand from an array of fish meal plants operating all along the Karnataka coast. In Karwar the LVB landed by single day operating trawls was about 42 % (2,310 t) in 2011.

In Calicut also there was high demand for the LVB by fishmeal plants and in this centre,

LVB landing in 2011 was 12,000 t forming 26% of the landed catch. In Kochi, at Munambam, the total estimated LVB landed in 2011 was 1,992 t forming 7.2% of total trawl landings and in

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Sakthikulangara fisheries harbour the estimated LVB in 2011 was 11% of the total landing. In Chennai, the estimated LVB landing was 13% (3,000 t) of the total landing in 2008 which increased to 17% in 2011(5,800 t).In Visakahapatnam, estimated LVB landed show a steady increase from 2% (705 t) of the landing in 2008 to 21% (19,000 t) in 2011 (Dineshbabu, 2014).

Bycatch from single day trawlers It is estimated that during the fishing year (2007-08) single day operating trawlers from Mangalore Fisheries harbour landed 1,601 t of fishes out of which 583t (36.44%) were of non edible, low valued fauna which is landed as trash. The highest trash landing was during December (47.2%). Stomatopods were the most dominant group among the bycatch, followed by finfishes, whereas, non-edible crabs, invertebrates, cephalopods and other molluscs were present in lesser quantities. the bycatch from single day trawlers consisted of 35 species of finfishes, 20 species of crustaceans, 20 species of gastropods, 3 species of echinoderms 2 species of coelenterates and one sea snake (Dineshbabu, 2014).

Bycatch and discards from multi-day trawlers In the multi-day trawlers total landing was estimated at 65,589 t. out of which 2,418 t (3.69%) were landed as trash, which formed part of the bycatch caught during the last two days of the fishing. The low valued bycatch caught earlier to the last two days were discarded, 14% of the catch was discarded during the process which amounts to be 9,199t. (Dineshbabu, 2014). Issues Excessive fishing effort

Excessive fishing pressure has resulted in stagnation and decline in the landings; decreased catch rates, incomes and intense competition and conflict among fishers.

Inappropriate exploitation pattern

The use of trawls with small-meshed cod-ends is a cause for concern from the point of view of growth overfishing, biodiversity loss and economic loss. Strict implementation of the legal cod-end mesh sizes in trawls would particularly help in preventing growth overfishing and restoration of stocks

Habitat degradation

Sea floor gets disturbed and damaging the corals, sea-grass and other biota due to continuous dragging of bottom trawls.

Non selective fishing

Trawls landing huge quantity of juveniles, discards and Low value bycatch which are not fetching good returns. Catching of juvenile leads to growth overfishing.

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Conclusion

1. Out of 35,228 trawlers in the fishery, Gujarat accounted for the maximum (32.9%) followed by Tamil Nadu (16.4%), Maharashtra (15.9%) and Kerala (10.4%).

2. The finfishes exploited by trawls belong to 21 major fish groups, out of which, sciaenids contributed maximum (18.4%) to the demersal landings along the Indian coast, followed by threadfin breams (17.3%).

3. The west coast of India contributed 51 % of the catch. Gujarat State accounted for 20% of the trawl landing of the country.

4. The nonedible portion of the landing steadily increased from 50,000 t in 2008 to one lakh t in 2011. The LVB at different centres increased from 16% of the total catch in 2008 to 27% in 2011.

5. single day operating trawlers from Mangalore Fisheries harbour landed 1,601 t of fishes out of which 583t (36.44%) were of non edible, low valued fauna which is landed as trash.

6. Out of the total, 14% of the catch was discarded from multiday trawlers at Mangalore coast


CMFRI (2012) Marine Fisheries Census 2010 Part I India. Ministry of Agriculture, Krishi Bhavan, New Delhi and CMFRI, Kochi. 98 p

CMFRI (2018) CMFRI Annual report. pp:1-302

Dineshbabu A. P., Radhakrishnan, E. V. Thomas, S., Maheswarudu, G., Manojkumar, P. P., Kizhakudan, S. J., Pillai, S. L., Chakraborty, R., Jose, J., Sarada, P. T. Sawant, P. B., Philipose, K. K., Deshmukh, V. D., Jayasankar, J., Ghosh, S., Koya. M., Purushottama, G. B. and Dash, G. 2014. An appraisal of trawl fisheries of India with special reference on the changing trends in bycatch utilization. Journal of the Marine Biological Association of India Vol. 55, No.2. p 69-78

Sreedhar, U., Prakash, R. R. and Rajeswari, G. (2010) Present scenario of the coastal and deep water trawl resources of southeast coast of India. In: coastal fishery resources of India: conservation and sustainable utilisation (Meenakumari, B., Boopendranath, M. R., Edwin, L., Sankar, T. V., Gopal N. and Ninan, G., Eds.). pp 77-89, Society of Fisheries Technologists (India), Cochin

Zacharia, P.U. (2012) Marine Fisheries Resources of India: Status and Prospectus. In: Fish harvesting systems for resource conservation (Thomas N. S., Edwin L., Pravin, P., Remesan, M. P., Ashraf, P. M., Baiju, M. V., Madhu, V. R., Eds), CIFT, Cochin. pp-28-42

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Sustainable Gillnet Fishing Saly N Thomas

Fishing Technology Division, ICAR-Central Institute of Fisheries Technology, Kochi E-mail: [email protected]

The origin of gillnetting cannot be traced back exactly, but reports of its

commercial existence dated back to 11th and 12th centuries. This fishing methodwithstood the technological and other transitional changes, the sector passed through such as introduction of bulk catching methods like purse seining and trawling. From a simple 20-30 m long piece of netting tied across a rivulet, it transformed to huge walls of netting running to 100 km and above in length and >50 m depth , with automated setting, hauling and catch removal.

Gillnet, a highly versatile gear, suitable for operation in the surface, column or

bottom layers of the water column can target fishes as small as anchovies to big sized sharks and rays. The gear can be operated even without a craft or with a non-motorised, motorised or mechanized craft. This fishing method is having the simplest configuration and method of operation. The simplicity of its design, construction, operation and its low energy requirement make the gear very popular in all the sectors especially in the traditional sector. However, as the scale of operation increases, the fishing method becomes labour and capital intensive. Over the years, there has been a tendency to use nets of increasingly larger dimensions. An illegal drift gillnet of 130 km long with Antarctic toothfish from the Antarctic waters was reported (Gibson, 2009).

Typical gillnet

A typical gillnet is a wall of netting held in a vertical position in water by floats on the upper end (head rope/float line) and sinkers at the lower end (foot rope/sinker line). Structure of a typical net is depicted in Fig. 1.

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Fig.1. Structure of a typical gillnet

The net consists of a main netting panel of specific dimensions, twine size and

mesh size, selvedge (top and bottom), float line, lead line, gavel line/ side ropes, floats, sinkers, buoys and buoy lines depending on the target fishery (Fig.1). Selvedge, generally of thicker material than the main netting is provided along the edges to give protection to the main webbing during handling and operation. Plastic and expanded poly vinelydene (PVC) floats are attached either directly to the head rope or to a separate float line, which runs along with the head rope. Sinkers are also attached likewise, either to the footrope or to a separate sinker line. Buoys attached through buoy lines to the head rope are for adjusting the floatation of the mounted net. Gavel lines or side ropes are attached to the side meshes of the netting. The required numbers of units are tied end to end depending on the size of the target species and area of operation.

Catching mechanism

Depending on the species targeted as well as design and configuration of net,

fishes are caught in gillnets by four types of catching mechanisms, viz., gilling, snagging, wedging and entangling. Gilling is the basic mechanism where in the mesh size is selected in such a way that the fish can only partly penetrate the mesh and on sensing the obstruction it tries to pull back. In its struggle to free itself the twine slips back over the gill cover and prevents the fish from escaping. Thus, the fish is gilled and hence called ‘gillnet’. The fish is also caught in gillnets by (i) snagging, when the fish is held tight by the twine of the mesh around its head; (ii) wedging, when the fish is held tight around its body; and (iii) entangling when the fish is held in the net by the teeth, opercular spines or

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other protruding appendages of the body without actually entering the mesh. The mode of capture depends on looseness of the net and the body shape of the target fish. Classification

The gillnet sector is classified into non-motorized, motorized and mechanized sub-sectors based on the vessel category in use. Gillnets are generally classified based on type of capture, structure, area of operation, method of operation and targeted species. Based on mesh size, Indian gillnets are classified into small mesh nets with 14 to 45 mm mesh size range and large mesh nets with 45 to 500 mm mesh size range.

Simple gillnets, vertical line gillnets and frame nets are single walled gillnets while trammel (triple walled) and semi trammel (double walled) nets come under multi walled nets. The vertical line nets - are simple gillnets, which are divided into different sections by passing vertical lines from the head rope to the footrope through the meshes of the webbing. Frame nets are single walled nets whose slackness is increased by attaching vertical and horizontal lines between the main lines dividing the main webbing to compartments of 1 to 1.5 sq. m. Trammel nets are triple walled nets having a loosely hung centre wall of small mesh netting which is bordered on each side by tightly hung walls of large open meshes. Fishes swimming through the outer meshes encounter the centre netting and push their way through the opposite outer meshes getting trapped in the resulting pockets that are formed. The outer meshes on one side of the net must be a mirror image of the outer meshes on the opposite side.

Depending on the mode of operation, there are drift nets (which drift freely with

both ends free or with one end attached to the vessel), set nets (anchored or stalked to the sea bed) and encircling nets (the fishes are surrounded and driven from the centre by noise or other means). Classification into surface, column and bottom gillnets is dependent on the depth of water column at which they are operated. Based on target species nets are also classified viz; nets for anchovy, lesser sardine, sardine, mackerel, prawn, mullet, crab, lobster, pomfret, hilsa, ghol, seer, tuna, shark, catfish, perch, snapper, rock cod etc.

Design parameters

The design of a gillnet depends on target species, its characteristic body shape, behaviour and swimming layer. The main parameters to be considered while designing a gillnet are: (i) size of mesh in relation to the size of the targeted fish, (ii) diameter of the twine in relation to mesh size, (iii) hanging coefficient (looseness of the net, (iv) visibility of the net, (v) softness of the material and the (vi) buoyancy and ballast given. The mesh size is the most critical factor as it selects the fish by body size or shape. Gillnet is the only gear in which the mesh itself serves the dual function of catching fish and

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selecting the fish to be caught (Yamaha, 1994). The mesh size, the material the net is made of, its thickness and colour and the hanging ratio of the nets perform these two functions. Any fish which is too small for the mesh size will be able to slip through the net and escape, while any fish that is too large on the other hand will not pass through and be able to escape the way it came. Techniques of operation

Gillnet operation has been a relatively simple method compared to other fishing gears. Nets are set across the current and in the path of fish migration. The method of operation varies with fishing condition, depth and area of operation as also the species to be caught. Gillnets are operated mainly as drift, and also as set and encircling gear. In certain cases, the net is dragged with the help of two boats. The nets are held at the bottom, mid water or surface,depending on the target fish and depth of operation. The soaking time of the net varies from 1 to 6 h for drift nets and 12 to 24 h for set nets. In set gillnet, both ends of the gear are secured to the sea bottom by means of sinkers or anchors.

The nets are shot mostly from the side and sometimes from the stern of the vessel.

The nets stored in the vessel with the float line and floats, buoy line and buoys to one side and sinker line and sinkers to the other side are thrown overboard to either side of the vessel to prevent tangling. Nets operated during night have lamps attached to a flagpole at the extreme end of the fleet and in between to keep track of the net. Energy efficiency

In the background of alarming increase of fuel costs, gillnetting can be encouraged as an energy efficient gear. Gillnet fishing consumes only 0.15-0.25 kg of fuel per kg of fish caught, compared to trawling which consumes 0.8 kg (Gulbrandsen, 1986). The energy efficiency of gillnets in comparison to ring seine (mini purse seine) is confirmed in the Indian conditions also (Thomas, 2001; Edwin, 1997). Gillnets operated in coastal waters of Kerala, consumed 0.46 kg of fuel per kg of fish caught (Thomas, 2001). The revenue realized per rupee of fuel for ring seine during 1995-96 was Rs. 3.24 (Edwin, 1997) while the corresponding values for motorized gillnet and mechanized gillnet were Rs. 4.5 and Rs. 5.0 respectively (Thomas, 2001). Till recently, setting and hauling of gillnet has been done exclusively manual even in large mechanized gillnetters, mechanical energy for propulsion alone. From 2012 onwards, mechanized gillnetters deploying large volume of nets started using mechanical gillnet winches/haulers. Such measures ease out fishers’ physical strain but add to fuel use.

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Selectivity

Gillnets are typically size selective as the capture by gilling, wedging and entangling is dependent on the shape of the particular species of fish encountered. Gillnets generally have bell-shaped selection curves described by normal distribution (Fig. 2). Width of the curve represents the selection range and the height corresponds to optimum size of fish caught by the gear. In symmetrical curve, the ability to catch fish decreases equally on both sides. The left slope of selection curve represents smaller fish wedged in the meshes and the right slope represents larger fish mainly tangled by head parts.

Fig. 2. Typical selectivity curve for gillnets

Gillnet selection curve becomes broader and more skewed to the right when many fishes are entangled and may approach the normal curve when most fishes are wedged/gilled. The mode of capture depends on form of body, gear material and hanging coefficient. Multi-model selectivity curves may be expected whenever capture is concentrated at body discontinuities such as maxillaries or spines. High selectivity of gillnets is a major advantage for sustainable harvesting of the resources.

Sustainability challenges

No fishing gear is perfect which does not have any impact on the environment. Among different gears, gillnets are considered as having very low environmental impacts as the sea bed interaction is bare minimum in most circumstances. Besides, being a highly selective gear catching a narrow size range of fishes, it was considered as a very

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responsible fishing gear till two to three decades before. However, these attributes given to gillnets started losing by early 1990s due to the large incidence of capture of marine mammals, turtles and sea birds in the high sea drift gillnets. Bycatch including juveniles, ALDFG and ghost fishing are the major problems associated with gillnets.

The intensification of fishing capacity through use of very large volume of nets extending to 100s of kilometres and rigging the nets loosely gave chances of non-target organisms including cetaceans and turtles getting entangled in the nets during fishing as well as through ghost fishing by lost nets. Consequently, use of drift gillnets at large-scale/industrial level in the western Pacific Ocean for tuna was discontinued after 1992. In the Northeast Atlantic, the use of driftnets was legal only until 2002 with the net length limited to not more than 2.5 km. However, driftnets continued to be widely used, in all coastal and small to medium-scale and large-scale fisheries worldwide. Major reasons adversely affecting sustainable gillnetting are increasing fishing effort, use of multi-mesh gillnets and mesh sizes below the optimum and use of loosely hung nets. Besides, the widespread use of very thin monofilament gillnets also is an area of concern. Major reasons associated with gillnet design and operation which adversely affect the sustainability of operation are discussed below. Increasing fishing effort

A major reason for many of the issues associated with gillnets is the steady increase in fishing effort viz.,increase in vessel size, engine power, volume of net deployed per operation , fishing time and soaking time all of which collectively add to the total fishing effort. Over the past 6 to 7 decades, there has been a substantial increase in the fishing effort by all the three gillnet categories viz., non-motorized, motorized and mechanized sub-sectors. In India, the length and depth of gill net increased from 150x3 m in 1950s to 18000x20 m at present. Currently, the mechanized gillnetters categorized as small (<12.0 m LOA) medium (12.1-16 m LOA) and large (16.1 -24.6 m LOA) with 60, 120 and 193 hp engines respectively, are deploying large net fleets of 5 to 16 km long and 8 -20 m deep (weighing upto 3 tonnes). In the non-motorized sector; and motorized sub-sectors also, the corresponding increase in net volume is alarming. Use of multi-mesh and non-optimum mesh size

A wider spectrum of mesh sizes is used in the commercial fisheries, which may differ from the optimum. Optimum mesh sizes have been worked out for some of the commercially important fishes (Table 1). However, the fleet of gillnets operated in commercial fisheries often consists of units of more than one mesh size attached end to end. This results in different species and different size groups of same species in the landings. Thus, in spite of the known selectivity of gillnet for a particular narrow size range of fishes, the use of different mesh sizes results in the landing of a wide size range

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of the species and size groups. There has been reports that in the coastal waters of India, juveniles and non-target species are landed using multi-mesh gillnets and gillnets with mesh sizes smaller than the optimum for a particular target species.

Table 1. Optimum and commonly used gillnet mesh sizes in commercial fisheries

Gillnet

type

Targeted

fish

Commonly used mesh sizes in commercial

fisheries (mm)

Optimum mesh size

(mm)

Sardine net Indian oil sardine (Sardinella longiceps)

30, 32, 33, 36, 38, 40 33.4

Mackerel net Indian mackerel (Rastrelliger kanagurta)

38, 40, 50, 52 50

Seer drift net Narrow-barred Spanish mackerel (Scomberomorus commerson)

70, 90, 100, 110, 120, 140, 170

152

Seer drift net Indo-Pacific king mackerel (Scomberomorus guttatus)

65, 70, 90, 100 104

Pomfret net Silver pomfret (Pampus argenteus)

110, 116, 120, 130 126

Prawn net Fenneropenaeus indicus 32, 34, 36, 38, 48, 50, 52 38 Tuna drift net

Frigate tuna (Auxis thazard)

60, 65, 70, 90, 100, 115 84

Tuna drift net

Kawakawa (Euthynnus affinis)

60, 65, 70, 90, 100, 115 104.2

Sardine net Goldstripe sardinella (Sardinella gibbosa)

25, 26, 28, 30, 32 29.6

Sardine net Spotted sardinella Ambligaster sirm

25, 26, 28, 30, 32 30.5

Loosely hung nets

Selectivity of gillnets mainly depends on the mesh size and configuration, which in turn, is influenced by the hanging coefficient. Sainsbury (1996) suggested that for gilling the fish, hanging coefficient is usually between 0.5 and 0.66 with 0.6 being common. For

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large mesh gillnets targeting pomfrets and mackerel, it is around 0.5 while that for seerfishes, tunas and sharks it is around 0.45 ranging between 0.41 and 0.65 (Thomas et al ., 2005). As the hanging coefficient decreases below 0.5, there are chances of entangling resulting in non-uniformity in the size class of fishes caught. Rigging of nets at a hanging coefficient of less than 0.5 is common. Drift nets especially large mesh nets targeting large pelagics are hung very loosely without even having foot rope and sinkers enabling easy entangling of large and fast swimming fishes.

Monofilament gillnets

Introduction of nylon monofilament material in early 1990s was a remarkable technological intervention adopted instantly by fishers. By late 1990s it became very popular and by early 2000 it almost replaced all gillnet types except large mesh nets targeting large pelagics. Unlike multifilament nets, monofilament nets mostly follow a `use and throw’ style as it is difficult to mend the nets, which is not a healthy practice. Monofilament nets last hardly for a season (2 – 6 months) and unless properly discarded, these nets will end up in ocean adding to plastic pollution, ALDFG and ghost fishing.

Bycatch problem

Loosely hung drift gillnets entangle non-target species and juveniles of target species. Specialized gillnets for oceanic fishing when allowed to drift with wind and currents, gill, entangle and enmesh a wide range of living marine organisms such as birds, turtles and marine mammals threatening the large marine ecosystem. Juveniles

Practices such as using multi-mesh gillnets, nets with mesh size smaller than the optimum and not adhering to resource specific gillnets lead to juvenile landings. Review of the size composition of species from gillnet landings in various locations of India showed that the bulk of the landings comprised of juveniles. In multi species fishery, complete avoidance of juvenile landings is not practical, but sasonal use of resource specific gillnets can limit juvenile catch to a great extent. ALDFG

Abandoned, lost and discarded gear (ALDFG) is the internationally recognized

name for derelict fishing gear (DFG). UNEP defines ALDFG as the “multitude of nets, lines, traps, and other commercial or recreational fishing equipment that has been lost, abandoned or otherwise discarded in the marine environment”. ALDFG has detrimental impacts such as destruction of habitats, entangling with marine turtles, seabirds, dolphins, whales, seals etc, introduction of invasive species, hazards to navigation and safety of life at sea and adverse effects on tourism, human health and safety.

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Gear loss due to abandonment, accidental loss and purposeful discard is a serious problem getting attention world over in the past few decades. Gillnets and traps are considered more susceptible to losses. Uses of very large volume of nets, rough weather, entanglement with bottom obstructions, purposeful discard etc are reasons for gear loss. ALDFG drifts with wind and waves and entangle aquatic animals and finally ends up on the ocean floor and on coral reefs destroying the ecosystem and also adds to marine debris. As per the FAO estimates, the average loss of gillnets and traps per year is 10%. ALDFG contributes around 10% of global marine litter by volume and an estimated 6.4 million tonnes of marine debris are added to global seas annually (UNEP, 2005a). The pioneering study by ICAR-CIFT in 2017-18 on ALDFG in Indian waters relating to gillnets and trammel nets has brought to light the seriousness of the issue in the country demanding immediate attention. Restriction on use of very large volume of nets, use of quality material and avoidance of operation in very rough weather and in areas with bottom obstructions could reduce loss of gillnets. Fishers are be encouraged to use materials with standard quality specification as the use of low quality and old/damaged netting give more chances for gear loss. Beides, absence of disposal facilities at the harbor and landing centres, for damaged net is also a problem faced by fishers. Ghost fishing

Nets, lines, and traps that become ALDFG, continue to catch, entangle and harm

marine animals without human control and is termed as ghost fishing. Gillnets, trammel nets and traps have relatively high ghost fishing potential. Gillnets are more likely to become ALDFG and do ghost fishing resulting in unaccounted mortality of fish and other aquatic organisms including endangered species. As long as the gear configuration is intact, the gear continues to fish. Gillnets are reported to have 3 to 9 months ghost fishing capacity. There are no authentic reports on ghost fishing from Indian waters. The deployment of long nets and extensive use of monofilament gillnets by Indian fishers, pause high risks of gear loss and consequent ghost fishing in Indian waters. Use of biodegradable materials in rigging floats on the nets would reduce ghost fishing ability of lost nets. Marine turtles

The incidental catch of marine turtles is associated with drift gillnets across the world. This happens in active gillnet as well as in lost gillnets. The problem is severe in India also and is more pronounced along the coasts of West Bengal, Orissa, Andhra Pradesh and Tamil Nadu. Fishing ban in areas of intense nesting of turtles during the nesting period is widely used to prevent turtle bycatch. Net illumination with light-emitting diodes (LEDs) placed on float line is suggested as an effective conservation tool to reduce marine turtle bycatch in gillnet fishery (Ortiz et al., 2016).

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Marine mammals Marine mammal entanglement in gillnets is a widely reported problem worldwide.

Chances of entanglement are more in surface drift nets. In India, there is no reliable data on the number of mammals caught incidentally in drift gillnets during fishing or after becoming ALDFG. Reduction in height of the net, use of aquatic pingers, increasing the reflectivity of net by treating with barium sulphate (Ba SO4), use of stiff ropes, biodegradable/weak seams and setting the net just below the surface are mitigation measures to reduce mammal interaction. Sea birds

Sea birds are occasionally caught in surface driftgillnets. Entangling of sea birds in

derelict nets is also widely reported. However, reports on bird mortality from gillnets are almost nil from India (FAO, 2017). Management measures Fishing gear regulation

The uncontrolled increase in volume of gillnet, demands restriction. Though mesh size regulation is enacted by many maritime states, maximum allowable dimension (length and hung depth) of gillnets is not specified by any of the states. Kerala, for the first time in the country, amended the KMFR Act and Rules in 2018, and brought out regulations on the dimensions of the gear for gillnets targeted for seven important commercial fishes. The maximum dimensions prescribed for small mesh gillnets are 2000 m length x 10 m hung depth and for large mesh gillnets are 5000 m length x 18 m hung depth.

Implementation of mesh size regulation in commercial gillnet fisheries would help to a large extent in sustainable harvesting of resources. Many coastal states of India have come out with minimum mesh size regulation for gillnet fishery under the Marine Fishing Regulation Acts while Kerala has enacted it for seven gillnet types (Table 2).

Table 2. Mesh size regulations pertaining to gillnets, in different

maritime states

State/UT Minimum mesh size prescribed for gillnets

Gujarat 150 mm Maharashtra Not prescribed

Goa 24 mm for fish gillnets and 20 mm for prawn gillnets

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Karnataka Not prescribed

Kerala Prescribed for 7 gillnet types (minimum is 33 mm for sardine gillnets)

Tamil Nadu 25 mm Andhra Pradesh 15 mm Orissa Not prescribed West Bengal 25 mm Andaman and Nicobar Islands

25 mm

Lakshadweep Islands 50 mm Source: Shenoy and Biradar (2005); Govt of Kerala (2018)

Minimum legal size of fish For the first time in the country, Kerala state has prescribed minimum legal size for 58 species of fish and shellfish to be landed. By following optimum mesh size, minimum size of fish to be landed by gillnets can be decided. Gillnets being highly size selective, strict adherence to optimum mesh size for specific fishery would help in reducing juvenile bycatch. Conclusion

Gillnets have great scope in sustainable harvesting of resources, being a highly size selective gear. In the context of energy intensive fishing operations ecoming un–economical, being a low energy gear, importance of gillnet cannot be undermined. However, the uncontrolled expansion in the volume of gear, use of mesh sizes less than the optimum, wide spread use of very thin nylon monofilament gillnets etc make this gear a threat to the environment and the resources. Fishers are to be made aware of the ways to avoid losing of gillnets and on the negative impacts of ALDFG and ghost fishing. Besides, proper disposal facilities for damaged net is also to be made available by authorities. Enforcement of regulations by proper monitoring and surveillance is necessary for the continued harvesting of resources in a sustainable way. If proper care is taken to responsibly design and operate, gillnetting can continue to be a very sustainable fishing method.

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References/suggested reading Edwin, L. (1997) Studies on the Ring Seine Fisheries of South Kerala Coast, Ph.D. Thesis, Cochin University

of Science and Technology, Cochin: 189p

FAO (2017) Proceedings of the expert workshop on estimating food loss and wasted resources from gillnet and trammel net fishing operations, 8–10 April 2015, Cochin, India, Petri Suuronen, Susana V. Siar, Leela Edwin, Saly N. Thomas, P. Pravinand Eric Gilman (Eds). FAO Fisheries and Aquaculture Proceedings No. 44. Rome, Italy

Gibson, E. (2009) Fishing horror revealed as gillnet ban looks likely, www.nzherald.co.nz/eloise-gibson/news (accessed on17.6.2010)

Govt of Kerala (2018) Kerala Gazette Extra ordinary Notification, 36p

Gulbrandsen, O. (1986). Reducing Fuel Costs in Small Scale Fishing Boats, BOBP/WP/27, Bay of Bengal Programme, Madras, 18p

Ortiz, N., J.C. Mangel, J. Wang, J. Alfaro-Shigueto, S. Pingo, A. Jimenez, T. Suarez, Y. Swimmer, F. Carvalho & B.J. Godley. (2016) Reducing green sea turtle bycatch in small-scale fisheries using illuminated gillnets: the cost of saving a sea turtle. Marine Ecology Progress Series. 545: 251-259. DOI 10.3354/meps11610

Thomas, S.N. (2001) Gillnets of Kerala: A Study on Technological and Operational Aspects, Ph.D. Thesis, Cochin University of Science and Technology, Cochin: 189 p

Thomas, S.N., Meenakumari, B., Pravin, P. and Mathai, P.G. (2005) Gillnets in the Marine Fisheries of India, Monograph, Central Institute of Fisheries Technology, Cochin: 45 p

UNEP (2005a). Marine litter: an analytical overview [online]. Nairobi. [Cited 25 April 2014]. www.unep.org/regionalseas/ marinelitter/publications/docs/anl_oview.pdf

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Gillnet fishing in Reservoirs: Problems and Solutions K. M. Sandhya

ICAR- Central Institute of Fisheries Technology, Kochi


Reservoir fisheries in India

Reservoirs in India are prime resources for capture fisheries and extensive aquaculture. Although the main purposes of reservoirs are irrigation and hydro electricity, fisheries also forms an integral part as a natural resource. Reservoirs extending over an area of 3.15 million ha having average productivity of 20 kg/ha contribute considerably to the inland fish production in India (Sugunan, 1995 & 2011). Exploitation of fisheries in these areas was insignificant in the earlier years where fishing was being conducted purely on a subsistence level. The last few decades have witnessed many technological advances in fishing systems in reservoirs.

Indian reservoirs being tropical, have high primary productivity and also have the

capacity to yield more fish production. Reservoirs in India mainly harbour rich variety of fishes in which the Indian Major Carps (IMCs) occupy a prominent place among commercially important species. They also harbour other carps, catfishes and miscellaneous species. Stocking is the mainstay of fish production in reservoirs and generally, the IMCs comprising fish species such as Catla catla , Labeo rohita and Cirrhinus mrigala form the core species for stocking across the country. Exploitation methods have great influence on the development of fishing and to harvest the multispecies fishery, different fishing gears and techniques are to be employed to realise optimum harvest.

Fishing methods in reservoirs

Fish capturing methods are varied in different inland water bodies depending on topography, ecology and habitat of the fishery resources. The indigenous or native gear operated in the riverine conditions are not suitable in the lacustrine condition of reservoirs which are rich in fishery resources and the fishery managers are facing problems due to lack of suitable fishing techniques. The presence of underwater obstacles such as stones, tree trunks, submerged plants and trenches restrict the use of active fishing gears like trawls in the reservoirs and fishers mostly depend on passive gears like gillnets. Due to its lower capital investment, simple design, construction and operation, gillnetting is widely practised in the reservoir which is recognised as an energy efficient, selective and profitable gear. Although other fishing gears such as seine nets, cast nets, scoop nets, hand lines and traps are also operated, their contribution is insignificant.

Gillnet fishing in reservoirs

Fishing gears in common use in reservoirs are gillnets and typical gillnets design have a head rope with floats and with or without footrope and sinkers. Gillnets are usually operated in the night, setting usually done before sunset and hauling by morning. However, operation during daytime is common during the migratory period of the fish and flood months. In majority of reservoirs gillnets made of Polyamide (PA) monofilaments are used (0.16mm to 0.4mm diameter) while PA multifilaments are also in use (210x1x2 to 210x6x3). Mesh size ranges from 20 mm to 310 mm. Floats are either of thermocol or expanded polystyrene and plastic. Nowadays

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empty plastic bottles are mostly used as floats in gillnets operated in reservoirs. Lead is the most common sinker material used in gillnets where the size, shape and weight vary according to the type of net and mode of operation. Clay, concrete or pieces of stones are also used as sinkers. Gillnets are generally rigged at a hanging coefficient of 0.5. Nets range in size from 10 m to 1000 m and 1 to 15 m depth.

Based on operation, two types of gillnets are used in reservoirs, set gillnets and drift

gillnets. Most prominently, set gillnets are used which are set either in the surface or column layers and anchored to the bottom by means of heavy weights like stone anchors or are tied to poles or sticks fixed to the ground (Fig 1 & 2). All kinds of fishes and prawns are caught in these nets. In drift gillnets used in reservoirs, the one end of the net is tied to the buoy while the other end flows freely and drifting is mainly due to wind action (Fig. 3).

Problems and issues in gillnet fishing

Although gillnet is known to be effective and highly selective for capturing fishes in reservoirs, some issues are also associated with gillnet fishing which are described below. Improper design parameters and associated bycatches.

Incorrect mesh size, diameter of yarn/twine, incorrect hanging of the webbing to the float line, omission of lead line and breast lines, incorrect rigging with floats and sinkers and improper height may result in catching of bycatches. Bycatch which is the incidental capture of non- targeted organisms in commercial fisheries, is a growing concern and an important conservation issue causing mortality and injuries to the non-target species affecting the ecosystem and survival of population. Bycatch issues have increased exponentially in recent decades and studies have focused primarily on marine systems while bycatch issues in freshwater bodies are relatively less studied (Raby, 2011). Loosely hung nets lead to capture by entangling resulting catch of non-target species and juveniles.

Lack of fishing control measures

In reservoirs, due to the absence of mesh regulation as well as landing size limitation for fishes, fishers use meshsizes smaller than the optimum for a particular target species leading to capture of juveniles. Due to the gillnet selectivity effect, a specific mesh size is often most effective for a narrow size range of fish. But fishers often use multimesh gillnets which cause capture of different size groups of particular species. In addition, the fishing effort in relation to the fishing area of the reservoir might have been excessive and adversely affecting the fishery. Ghost fishing

In most of the reservoirs in the country, gillnets are made of PA monofilament yarn of very thin diameter of 0.16mm to 0.2mm which lasts for hardly 3 to 6 months due to breakage, tear and weathering effects. Usually these fine gillnets are thrown by fishers after a season’s use since they do not repair the net once damaged. This can be harmful to the ecosystem as once these nets ends up in reservoir, may lead to ghost fishing related problems. These nets will continue to catch fish and other aquatic organisms for indefinite period of time. Information on ghost nets in the oceans are relatively well known, but such nets may be present in reservoirs also, especially those which were flooded before being cleared of trees and undergrowth. There is limited information on the quantity of lost nets and their impacts in reservoirs. In 1990’s over 5 tonnes of ghost fishing nets were retrieved under “ghost net eradication programme” launched in

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Laos for the management of NamNgum reservoir (Matics, 1997) with the co operation of local fishers.

Post harvest losses

Set gillnets which are often left in reservoirs for hours extending 12 to 24 hours lead to spoilage of fish caught in the initial hours of setting. These losses occur due to inordinate delay in taking out the catches from gill nets. The extent of loss from 6.52 to 8.89% where reported in Hirakud reservoir area (Jeeva et al., 2006). In addition, the inflow of muddy water during post-monsoon season was also a factor causing mortality of fish caught in the gears.

Improper stocking and monitoring

The availability of commercially important high value species is less in reservoirs due to improper and inadequate stocking. Use of small meshed gillnets in reservoirs during the stocking period adversely affects the production.

Solutions to gillnet fishing problems

Most reservoirs have tree stumps in the bottom which create difficulty for fishers to use gillnets in those areas where nets get entangled. In such reservoirs, gillnets without footrope and sinkers can be operated to reduce the extent of this problem. Improvemnts /design modifications as well as optimum mesh parameters of gillnets suitable for Indian reservoirs have been discussed by Sulochenan et al (1968), Nair et al (1969), Kuriyan (1973), George et al (1973), Natarajan (1979), Kartha & Rao (1991), Pravin et al (2014), Sundaramoorthy (2013) and others. The efficiency of gillnets is influenced by factors such as mesh size, colour, fishing height, hanging ratio, yarn/twine diameter and gear material. In order to tackle many of the problems associated with reservoir gillnet fishing, solutions recommended are given below.

Gear material

Introduction of synthetic fibres like PA/ nylon in place of natural fibres improved the catching efficiency of gillnets in reservoirs. There is a gradual shift in the usage from PA multifilament to PA monofilament which have shown more improvement in catches due to their softness and very low visibility in water. High density polyethylene (HDPE) monofilament yarn, twine and fibrillated tape are later additions as new cheap and effective substitute to nylon multifilament. Recent studies also showed that Polyproplyene is also more efficient having equal fishing power and cost effective compared to other materials.

Design modifications & upgradations

Simple gillnets, mainly entangling type, the typical amongst them being Rangoon nets was the basic design adopted for fishing operation at the surface and column layers in almost all reservoirs in the country with local modifications based on fishery. The gear was introduced in Mettur reservoir and having a head rope with floats wheras footrope was absent to increase the entangling capacity. The first attempt to increase the efficiency of lacustrine gillnets were by modifying the gillnets having headrope and footrope and with floats and sinkers respectively at regular intervals.

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Studies have shown that for relatively larger fishes, the mechanism of capture is more by entangling than gilling and to increase the entangling capacity, the webbing should have more slackness. There were many modifications made in simple gillnets to improve the slackness through vertical lines or framing. In vertical line nets, slackness is improved by providing vertical lines in the net from headrope to footrope. In framed nets, slackness is increased by passing vertical and horizontal lines between the mainlines dividing the main webbing into compartments (Fig 4). Framed nets are generally more efficient than 'simple gill nets because apart from having greater horizontal and vertical slackness, their design creates small net bags in which fish become tangled as well as gilled. Both framed nets and vertical line nets are found to be more effective especially in reservoirs where the fish population is less and consisting of larger species (George, 2002). However, simple gillnets are reported to be more effective in reservoirs where small size group of fishes are in abundance. Trammel nets, the three layered nets, with an inner loosely hung wall of small mesh and two outside armourings of large mesh wall on either side of the small mesh wall were also introduced and output was greater than simple gillnets, but was comparatively less efficient than framed nets. Optimum mesh size

Gillnets are known to be size selective where one mesh size only is most selective for a small size interval of fish and therefore not catching smaller or larger fish at the same rate. Knowledge of size-selectivity is, therefore, important in fisheries management to understand developments of the fish stocks. It helps to make the right choice of mesh size to suit the available fish population. With the right choice of mesh size nets can allow fish to attain sexual maturity and reproduce at least once before capture. Thus by using appropriate mesh size, overexploitation and capture of juveniles can be avoided and bycatch can be reduced to a minimum, as not many species other than the targeted fishes will be caught. Optimal mesh size estimates for the major species in reservoirs are given in Table 1.

Mesh size regulations exist in reservoirs in different states of India. The management of reservoir fishing in Himachal Pradesh is noteworthy where control measures like mesh regulations, closed season are strictly monitored and can be followed by other states for maximum production and sustenance of fisheries.

Table1. Optimum meshsize estimates of gillnets for selected fish species in some

reservoirs in India

Species Reservoir Optimum mesh size (mm) Catla catla Gandhisagar 148 Labeo rohita Gandhisagar 89 Cirrhinus mrigala Gandhisagar 60 Labeo calbasu Gandhisagar 53 Catla catla Hirakud 90 Silondia silondia Hirakud 75 Labeo calbasu Gobindsagar 53 Labeo diplostomus Gobindsagar 50 Labeo bata Gobindsagar 55 Catla catla Aliyar 137 Catla catla Nagarjunasagar 91 Cirrhinus mrigala Nagarjunasagar 41 Labeo calbasu Nagarjunasagar 52

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Fig. 1. Surface set gillnets (Catla nets) in reservoir with stone anchors

Fig. 2. Surface set gillnets in reservoirs anchored by poles

Fig. 3. Drift gillnets in reservoir

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Fig. 4. Framed gillnet

Visibility of the net

Visibility of the nets depends on net colour, type of material, thickness of yarn/ twine and

the tone contrast with the background, which can be affected by the time of day and the seasonal changes in water clarity or colour. Monofilament nets nearly invisible in water, are usually the most efficient. The effect of net colour can vary with species, because of differences in behaviour or colour sensitivity. Selection of right colour can reduce catches of unwanted species, without affecting catches of the target species. Studies in reservoirs by CIFT have showed that net materials of yellow and orange colour are most suited for Gobindsagar reservoir whereas in Hirakud reservoir better catches could be obtained by using green and yellow coloured nets. In Thirumoorthy reservoir, white coloured nets were found to give more catch (Velmurugan et al., 2016).

Thickness of netting material

Thickness of yarn/ twine in relation to mesh size play a vital role in determining the efficiency and durability of the net. It should have the maximum possible fineness and as soft as possible. Hence twines of smaller diameter having sufficient strength depending on the species of fish to be caught are to be selected. Firmness of fish body and extensibility of material are also to be taken into consideration while selecting the twine and mostly suited material are monofilament. Thinner netting materials are recommended where fish concentration is less and thicker materials where dense fish population exists. Hanging coefficient

Hanging coefficient determines the shape and opening of mesh, the distribution of forces and is one of the most important factors affecting yield and selectivity of gillnet. The entangling property can be increased by a decreased hanging ratio. Generally, nets having low hanging ratio (<0.5) can catch the larger individuals of the same species by entangling than gilling. A hanging coefficient of 0.50 and above is suitable for both gilling and entangling of different fishes.

Fishing height

Fishing height of the net is resource specific and regarded as a factor of importance for efficient fishing. Fishing height of 5.25 m was recommended in Catla gillnets and 3 m for other fishes like Labeo calbasu , L.bata, L.diplostomus in Hirakud reservoir. In Gandhisagar reservoir a

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fishing height of 3 m was found to be suitable for Catla catla and for L. calbasu. In different states the regulation on the length and height of the gillnet to be used in different reservoirs exist. In Himachal Pradesh which has a well managed reservoir fishery, height of gillnets in operation in reservoirs are limited to 80m and 5m respectively (Thomas, 2015).

Identification of potential fishing areas

Potential fishing ground can be located empirically in major reservoirs either by exploratory fishing or by productivity studies. Such studies were conducted in reservoirs such as Stanley, Thungabadra, Hirakud, Konar and Mettur. Acoustic methods have also been employed in Mettur and Dudhava reservoir. Similar studies can be expanded in other reservoirs also which will be helpful during post-impoundment studies where future fishing grounds can be predicted well in advance.

Future prospects

In the light of stabilizing marine fish catches, inland fisheries in particular, reservoir fishery potential need to be exploited. The gear suitability influences the fish catch in capture fisheries. It is a fact that a well-managed fishery is expected to use gear types that catch most of the available species at sizes that do not undermine the sustainability. The application of new technologies and innovations would be required to tap the fish production potential of the reservoirs in a sustainable manner. The following points can be taken into consideration for future development as well as making gillnet fishing an ecofriendly and sustainable fishing method in reservoirs.

• Updating of baseline data on the gillnet fishing in various reservoirs to evaluate the present

status which are essential for their up-gradation in future in terms of efficiency as well as

cost-effectiveness.

• Determination of the optimum mesh size for different species and size groups,

determination of optimum fishing height and standardisation of other parameters in

various reservoirs to improve the catching efficiency.

• Regular stocking programme with optimum stocking measures and exploitation policy

especially in the small reservoirs and those under medium category where autostocking is

not possible in order to use the productive potential of the reservoirs.

• Usage of gillnets with optimum mesh sizes should be encouraged to harvest different

species by giving training and awareness to fishers. Mesh size regulations, size limits and

total fishing effort have to be implemented and monitored for sustainable exploitation.

• Use of electronic fish detection devices, bottom profiling and mapping, clearing of tree

stumps/trunks for catch improvements. Refinement of empirical information available on

Potential Fishing Zones based on productivity studies, exploratory fishing, acoustic surveys

and remote sensing for potential fishing area marking.

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• Creating awareness among fishers on ecological impacts of abandoned, lost or otherwise

discarded gear (ALDFG) and also removal programmes of these ALDFG can be promoted.

Development of research strategies and counter measures to prevent gear losses, discards

or abandonment.

• Post-harvest losses in gillnet fishing can be minimised by reducing the soaking time and

avoiding the delay in harvest time.

• Transfer of developed techniques and appropriate training to fishers and stakeholders

through extension to adopt these techniques and to cooperate in implementing

management policies.


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Khan, A.A, Kartha, K.N, Dawson, P. and George, V.C. 1991. Fish Harvesting Systems in Indian Reservoirs. Proc. National Workshop on Low Energy Fishing. Society of Fisheries Technologists (India). pp: 152-155

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Matics, K. I. (1997) Ghost fishing in Laos. Mekong Fisheries Network Newsletter. 3(1): 1-2

Natarajan, A.V. (1976) Ecology and state of fishing development in some of the manmade reservoir in India. In: Proceedings of the Indo-Pacific Fisheries Council. 7* Session. Colombo, Sri Lanka

Nayar S., Gopalan, M., Shahul Hameed and Varghese, M. D. (1969) "Experimental fishing in Gandisagar reservoir, Madhya Pradesh" Paper presented at the Sym·posium "On ecology of reservoirs" C IF R I, Barrackpore

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Design, Operation of Long lines for Resource and Energy Conservation

U. Sreedhar Research Centre of ICAR-Central Institute of Fisheries Technology, Visakhapatnam


Introduction

The name of “longline” comes from the length of the lines that are used. In broad terms, a longline consists of a mainline where many branch lines are attached. Each branch line has a baited hook at its end. Longlines are proven to be a good fishing method for catching large, high quality and high value fish. Therefore, it has become a popular method from 1980s. Longline gear is used all over the world, from small-scale fishing to modern mechanised longline operations. The longline is a very simple fishing gear, but there are many variations in gear construction, fishing method and fishing strategy. The high fuel consumption of large-scale fishing has made the fishermen adopt low energy fishing methods. Trawl fishing is very costly in terms of fuel and not environmentally friendly. Longline fishing, on the other hand, does not require much fuel and is environmentally friendly. In order to protect fish resources, trawl and purse seine fishing are not permitted in inshore seas, only in offshore and in open seas, and small-scale fishing is widely practiced in inshore seas. Most of the developing nations are trying to find solutions to increase the catch amount without using trawl and purse seine fishing in inshore waters. One solution is developing longline fishing because it secures sustainable catching with less fuel consumption in inshore areas and protects fish resources. The proportion of crafts engaged in long lining is increasing every year. In the past fishermen mostly used the hand line but nowadays longline fishing is increasing. The vessels used for longline are medium-sized with 120-400 HP engines and small vessels with 14-28 HP engines. The structure of the vessels has been altered for doing small-scale fishing like longline. Squid and herring are mostly used for bait to catch demersal and semi pelagic fish. The bait size used in bottom set longline is based on fishermen’s experience. Baiting is done by hand and hauling is mostly done by powered haulers. Longline fishing in Indian waters is in its initial stages and problems remain to be solved. The technical information on longline has not yet been widely introduced to the relevant people. Scientific fishing methods are not widely used and the mechanisation of longline is in its infancy. Fishermen use different sizes of bait according to their experience. This may be one of the reasons for the decreasing catch rate. A good understanding on how to study different bait sizes is therefore very important. In longline fishing, several factors such as the hook, bait, branch line and mainline affect catch ability and selectivity. Classification of Longlines

Based on the structure and fishing method, longlines are classified into four categories:

drift longline, bottom set longline, vertical longline and bottom vertical longline (Hameed and Boopendranath 2000). In some cases, longline is grouped into two categories: surface longline and bottom longline, but this categorisation is based on the same principles as the first.

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What is long lining?

longline fishing uses a long mainline made of mostly nylon monofilament to which are attached hundreds or thousands of branchlines, each with a single baited hook. The line is suspended in the water by floatlines attached to floats, which may have flagpoles, lights, or radio beacons. Longlines are usually set and hauled once daily and are allowed to drift freely, or soak, for several hours while fishing. Longlines are set, either by hand or mechanically, while the boat steams away from the line and are usually hauled mechanically while the boat steams toward the line. The species targeted are tunas and some billfish.

Structure of longline A bit of history

longline fishing for oceanic species evolved in Japan during the nineteenth and early twentieth centuries. Sailboats equipped with hemp longlines would venture as far as 30 nm offshore from Japan in search of tuna and billfish. By 1912 there were over 100 registered sailboat tuna longliners in Japan. The first diesel powered steel longline vessels did not appear until the early 1920s. The longlines were hauled by hand until 1929 when the first mechanical Izui line hauler was developed. Improvements in fishing vessels, including the introduction of the internal combustion engine in the early 1900s, resulted in an expansion of the fishing grounds, enabling the Japanese to fish the Nojimasaki fishing grounds for albacore in the central Pacific by the early years of the Shôwa Era. The Japanese fleet had an operating radius of approximately 2000 miles eastward to the longitude of Midway Island (approximately 180° E) prior to World War II, although the vast majority of those vessels landed at their homeports in mainland Japan. Global expansion of longline fisheries began in the 1950s and 1960s, spreading throughout the Atlantic (North and South) and Mediterranean. This expansion was largely driven initially by the Japanese tuna market and supported by improved freezing technology and international transportation. Subsequently, liberalized trade regulations and emerging markets for swordfish and other species (e.g., shark fins for China) encouraged additional fleet expansion. Target Species

The main target species of oceanic longline fishing are tunas and billfish, while other

species including sharks can also is an important component of the catch. The catches of long line

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can be divided into three distinct categories: target, byproduct and by-catch. Tunas are by far the most important target species for longlining. The highest value species are bluefin tuna, followed by bigeye tuna, yellowfin tuna, and albacore tuna, in that order. Some billfish are also targeted, with broadbill swordfish being the most important, followed by striped marlin. Bigeye tuna

Bigeye tuna are the most valuable species caught in the longlines and are found

throughout the tropical and temperate waters in Pacific, Atlantic and Indian oceans. Fishermen targeting bigeye tuna set their lines deep because bigeye are often associated with the thermocline , which is found between 100 and 350 m, depending on the area and time of year. Bigeye tuna can be caught all year round in equatorial waters but are more seasonal in higher latitudes. The best bigeye catches are usually in the winter months. The most marketable bigeye tuna are those weighing 40 kg or more. Bigeye tuna are usually marketed as fresh chilled fish for sashimi. Yellowfin tuna

Yellowfin tuna are also found throughout the tropical and temperate waters of Pacific,

Atlantic and Indian oceans, but the stocks change as per the oceans. Although they can be caught in deeper water, longline caught yellowfin are usually taken in water from near the surface down to 250 m above the thermocline. This layer of water is called the mixed and intermediate layer. The preferred temperature range for yellowfin tuna is 18° to 28°C, which roughly corresponds to temperatures found in the mixed and intermediate layer. The best season for yellowfin tuna is in the spring and summer months. The most marketable yellowfin tuna are those that weigh 30 kg or more. Yellowfin are usually sold as fresh chilled fish for sashimi or to be used in cooking. Yellowfin is second to bigeye as a sashimi fish in quality and value. Albacore tuna

Albacare tuna are also found throughout the tropical and temperate waters of Pacific, Atlantic and Indian oceans. These fish are schooling fish and are caught seasonally, in the summer and autumn months, at the surface by troll boats, and are smaller than longline caught albacore. Larger fish are caught by longline in deep tropical and subtropical waters down to the depth of the thermocline. Depth and temperature ranges for longline caught albacore are similar to those for bigeye tuna. The season for longline albacore is not as apparent as for other tunas — autumn months in some locations, all year round with peaks in summer and in autumn and winter in other locations, and autumn and winter months in other areas. Longline caught albacore range from 15 to 20 kg and are sold frozen whole to canneries, fresh to export markets, or as frozen quarter-loins. Striped marlin

Striped marlins are found throughout the tropical and temperate of Pacific, Atlantic and

Indian Oceans. They are usually found in the upper mixed layer or near the surface. In fact, longline caught striped marlin are most often caught on the branchlines nearest the floats, the shallowest branchlines. They are not usually the main target species of longliners, but are caught

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in association with yellowfin tuna sets. The preferred surface temperature range for striped marlin is 20° to 23°C, although they can also be found in temperatures ranging from 15°to 26°C. The usual size range of striped marlin is 60 to 120 kg, although specimens up to 190 kg have been caught. Byproducts and By-catch of longlining:

Byproduct and byctch are species that are caught incidentally (not targeted) during

longline fishing, that have a commercial value and are retained for sale. These species include opah, black marlin, Indo-Pacific blue marlin, short bill spearfish, sailfish, skipjack tuna, mahi mahi, wahoo, pomfret, escolar and barracuda, amongst others. A range of shark species are also taken as byproduct, although they are mainly prized for their fins (finning is probably going to be phased out as more and more countries are adopting a policy where the entire shark must be retained). Black marlin, Indo-Pacific blue marlin, sailfish, skipjack tuna, mahi mahi and wahoo are distributed throughout the subtropical and tropical Pacific Ocean and are caught near the surface on the shallowest hooks in a set, near the floats. Conditions for catching these species are similar to conditions for catching yellowfin. Byproduct species such as pomfret, escolar and opah are usually found in deeper waters and are associated with bigeye catches. The most common species of shark taken by longlining include the blue shark, oceanic white tip shark, short-finned mako shark, silky shark, thresher shark and tiger shark. These are all pelagic or oceanic sharks. Sharks are mainly caught on the shallower set hooks during normal tuna longlining activity. Bycatch

Bycatch are the unwanted species that are taken incidentally during longlining, and are discarded as they have no commercial value. These species include snake mackerel, lancetfish, pelagic rays, seabirds and sea turtles, amongst others. Snake mackerel, lancetfish and pelagic rays can be taken at various depths on a longline, and are not really associated with a particular type of longline set. The fish are generally small in size. Seabirds, such as albatross, and sea turtles are sometimes caught on longlines. The seabirds attack the baits on the gear as it is being set, while the sea turtles are taken on the shallow hooks, generally near the floatline. The catch of seabirds and sea turtles by longliners has become an environmental issue as the animals are protected. This is an area of concern to all longline fishermen. Another form of bycatch are fish, both target and byproduct species, that have been damaged by sharks or toothed whales. In some cases, shark damaged fish may be retained for crew consumption or sale if the damage is limited. However, when toothed whales take fish, they only leave the heads, and these are discarded. Bait used in longline fishing

Bait used for longline fishing is usually frozen whole finfish such as sardines, saury, or

mackerel and scads. Frozen whole squid is often used for tuna longlining but is more important as bait for swordfish. Live milkfish is also used for tuna longlining. The average bait weighs about 80 to 100g. If the bait is much bigger than 120g it is likely that some target fish will be missed. Longline vessels

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Specialised vessels for longline fishing, longline vessels, operate throughout the world. The vessels are characterised by the rail roller, the longline hauler or the setting chute. Longline vessels may be classified by size (LOA) into small (8-15 m), medium (15-25 m) and large (25-50 m) longliners. Some vessels have the cabin forward and the working area aft, while others have the opposite layout. Both work successfully, and it is up to the individual to choose the size, design and layout he prefers.

Longline vessels with a foreward and aft wheel house

Small-scale longliners:

Small longline vessels are operated by one to three fishermen and the fishing trips are short (one or two days). The boats are mostly made of wood, fibreglass, steel or aluminium. Small-scale longline boats include artisanal vessels and catamarans that use either hydraulic or hand operated longline reels capable of setting and hauling 300 to 400 hooks per day. Most small-scale longliners use monofilament longline systems. These boats have limited operating range and limited fish holding capacity, but have been quite effective in some localities. What they lack in production capabilities is often made up for because they are inexpensive to purchase and operate. The traditional non mechanized and motorized traditional craft Catamarans and fiber catamarans of 21-36’LOA and 4’ width with outboard engine of 8-21HP and usually went out on day or overnight trips, and made just one or two sets in coastal waters ranging from 10 to 50 nm offshore. The crews on these vessels are might be three to six fishermen. The size and limited capacity of small-scale vessels greatly restricts their movement, and they cannot follow fish like the medium-scale vessels.

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Small-scale monohull longliner

Medium-scale longliners

Medium size longliners catch fish in coastal or inshore waters. Fishing trips usually last

from two to seven days and the number of fishermen is three to eight, depending on the fishing operation. A 20 m longliner may carry 90-100 sets of gear (30,000-40,000 hooks) during a two-day trip with four fishermen. Medium size longline vessels are normally equipped with engines of 250-600 HP, giving a maximum speed of 8-10 knots (4-5m/s). Medium-scale longliners have greater operating ranges and fish holding capacities than small-scale longliners and thus are able to fish within a country’s entire EEZ and even outside the EEZ on the high seas. Trawlers, bottom fish boats, trollers, and even squid jiggers have all been successfully converted to longline boats. Longliners can have single or multiple fish holds, fish preservation can be by ice or CSW or RSW, and the hull material can be steel, fibreglass, aluminium, or wood. Most of longlinng fleet in India belongs to this category.

Medium-scale longliners Large-scale longliners

Large longline vessels are built for deep-water fishing for more than three weeks at a time. The size and the structure differ according to the fishing operation. Some vessels are 40 to 60 m long and have 20-25 fishermen. Fishing trips are often 18 to 24 months. Some large longline vessels are used as combination vessels, gillnetting for herring and cod in winter and spring and longlining for tusk and ling on the coastal side and continental slop during summer and autumn, mainly based upon onboard baiting of the lines during one to two week trips. The latest development in large-scale longliners is a series of vessels built for fishing Patagonian toothfish at large depths (1,000-2,500 m) off Argentina (Bjordal and Løkkeborg 1996). Large-scale longliners

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include freezer albacore boats and freezer sashimi boats. Their operating range includes all of the world’s oceans. They can stay at sea for several months at a time, conducting from 50 to 100 sets or more per trip and setting from 2500 to 3500 hooks each day. They are capable of holding up to 100 mt or more of frozen fish. There are also a few large-scale longliners that target fish for export to overseas markets as fresh chilled fish.

Large-scale longliners The longline: Basic Gear Configuration

There are two basic types of longlines: traditional rope, also known as basket gear, and

monofilament gear with some combinations and variations. Basket gear evolved during the late nineteenth century and is still in use today, particularly in the Asian fleet. Monofilament gear evolved in the 1980s and revolutionised longline fishing by offering a less labour intensive and more efficient method of catching fish. Fundamentally, however, the two systems are similar. A longline is made up of units or sections of line that are called baskets. A basket of longline gear is the amount of mainline and branchlines in between two floats. The term is used both for basket gear and for monofilament gear. The mainline is suspended in the water by a series of floats, or buoys, that are attached to the mainline by floatlines. The line is set and hauled once a day from a moving vessel. It is allowed to drift or soak on its own for four to eight hours in between setting and hauling. A typical longline set from a medium-scale longliner would be about 30 to 60 nm long and have about 1200 to 2500 hooks. A typical longline trip on a medium-scale longliner would last about one to three weeks and the line would be set about 6 to 12 times once each fishing day. Description of Longline Gear

Longline gear consists of three basic components: the mainline, the branch line, and the

baited hook. All of these parts are adaptable for targeting specific species through changes in materials, lengths, and deployment strategies. For example, setting the mainline along the seafloor, a demersal set targets flatfish, cod, groupers and coastal sharks. Using small buoys and float lines to suspend the gear below the surface results in a pelagic longline set that targets pelagic tunas, swordfish, billfish and other free-swimming predators. In between these two extremes are a variety of different configurations that are adapted by local fisheries to target specific species.

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Gear construction Mainline

The mainline is the basic part of longline gear. Branch lines, buoy and sinker lines are attached to it. The mainline is characterised by the material, material construction and size. The length of the mainline varies according to the fishing ground, scale of fishing operation and other conditions. In large scale longline fishing, the length of the mainline can be up to 180 km. The thickness of the multifilament mainline generally ranges from 4 to 11 mm in diameter depending on the type of longline fishery. The mainline is made of highly specific gravity materials such as hard twisted polyamide, polyvinyl chloride or polyvinyl alcohol. In the past, natural fibres were used but now synthetic materials are widely used because of their higher breaking strength and higher resistance to deterioration. Mainlines are made with either multifilament or monofilament. Multifilament mainlines are made from fibre filaments that are twisted to threads and strands to make rope. A multifilament mainline is usually a twisted rope with three strands. Braided rope may also be used. Multifilament mainlines are normally treated with coal tar or some other impregnating material to improve the handling properties and the lifetime of the line. During the last 30 years, monofilament mainlines have been used in almost longline fishing because the catching performance of monofilament lines has been shown to be superior to that of multifilament lines. In contrast to multifilament lines, monofilament lines have one filament only, which is made from polyamide. Because of their low breaking strength and poor resistance to chafing, monofilament mainlines can seldom be laid on the bottom except on smooth sea beds. Monofilament mainlines are usually used in pelagic or semi pelagic longline fishing. The monofilament is given a certain heat treatment in order to obtain good coiling and handling properties (Bjordal and Løkkeborg 1996).

A longline set

Branch lines

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Branch lines are connected to the mainline at appropriate intervals. Branch lines affect the catch rate with regards to their material, length, thickness and the attachment. Monofilament branch lines give 10-29% higher catch rates for cod and haddock as compared to multifilament branch lines. Thinner branch lines give better catch rates than thick ones (Bjordal and Løkkeborg 1996). The branch line interval is determined by taking into consideration the biomass, the size of the fish and the convenience of operation. Species which are distributed over a large area (as for tuna) the branch lines are usually widely spaced and where fish is more concentrated as in demersal waters, they are comparatively closely spaced. The lower visibility of the monofilament branch lines results in higher catch rates. When the length of branch line is increased, the catch rate usually increases, but because longer branch lines tend to tangle easily, their length is limited to less than half the hook spacing. The length of the branch line varies according to the fishing operation. Multifilament branch lines may be from 0.3 m to several meters long. The length of the branch line together with the length of the buoy line and the shape of the mainline catenary attained during operation determines the fishing depth of hooks. When fish is hauled, it tends to rotate around its own axis and around the mainline. Thus twisting and shortening of the branch line take place. So due to reduction in flexibility, the possibility of the fish breaking loose and getting lost is increased. When branch lines made from monofilament material are attached to the mainline, there are some problems because they are slippery and stiff. To solve these problems, swivels are used to connect the branch lines to the mainline. Because swivels prevent twisting and tangling, monofilament lines with swivel give high catch rates. It has been proven that the swivel attachments improve the catch rate by about 15%, depending on the type of fishery, the target fish and the weather conditions (Bjordal and Løkkeborg 1996). Swivel connected branch lines make the de-twisting work of fisherman easy. Swivels also allow for the possibility of using a monofilament branch line with a multifilament mainline.

There are several pieces of hardware used in the construction of branchlines, including snaps, swivels, hooks and sleeves. Snaps

The swivel snap often called a clip is a very important component of a branchline. There are different snaps for rope and monofilament gear, and they should not be interchanged, as they will not work properly. Snaps made for rope gear have a jaw that is too big to grip monofilament mainline. A suitable monofilament snap has a tight jaw that grips the monofilament mainline. Swivels

The most common swivels used in branchline construction are the leaded types, which come in 38, 45, 60 and 75 g sizes. The leaded swivels are used to increase the sinking rate of the gear and baited hook, to add weight to keep the branchline deeper in the water, especially in rough weather, or to provide a connection point in the branchline between the main part and the leader. When branch lines made from monofilament material are attached to the mainline, there are some problems because they are slippery and stiff. To solve these problems, swivels are used to connect the branch lines to the mainline. Because swivels prevent twisting and tangling, monofilament lines with swivel give high catch rates.

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Branchline details (Bolaky, 2006)

Snaps Swivels

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Hook

The hook is the heart of the longline system. Everything else is just a means of getting the hook in front of the fish. The hook mainly consists of an eye, shank, bend, point, gap and throat. The hook types vary greatly and about 50,000 types of hooks have been designed. They can be classified into hooks for commercial and sport fishing. The hooks for longlines are chosen on experience, depending on the type of fish that one hopes to catch and its behaviour. The main factors, which characterise the hook, are shape, size and coating. The name of the hook indicates its basic shape, and the quality number identifies the varieties within this hook group. Hooks can be straight or with the point turned left or right. The shank may be forged, which makes the hook stronger and more resistant to forces acting in the hook.

Basic parts of a J hook made of steel, coated with different metals (Bjordal and Løkkeborg 1996)

Different kinds of hooks (Mustad Catalouge)

Circle hooks have shown that they have many advantages. The main advantage is the circular appearance of the hook with the barb of the hook pointing back towards the shank or the eye. The auto baiter type of hook is used in auto line systems. This kind of hook is a compromise between the circle hook and the strait shank required by the automatic baiters of some systems. In order to protect hooks from corrosion, they are coated with metals such as tin, nickel, cadmium or a combination of these metals, or other anti-corrosives. Hooks are used in various working conditions such as hooking and baiting. To fulfil the requirements of strength and elasticity in the working process, a hardening process is needed, which is critical to make the hooks neither too soft nor too brittle.

Floats, Flagpoles and Floatlines

There are several different types of floats used in longline fishing including glass floats, hard plastic floats, inflatable buoys, bullet buoys, and solid foam floats. The most popular floats for monofilament longline fishing are hard plastic floats that range from 165 to 360 mm in diameter. These floats usually have one or two ears, eyes for attaching line and are ribbed on the

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outside so they pull through the water easily. Glass floats were popular years ago with Japanese basket gear. Glass floats need to have a net made from tarred rope, as they do not have attachment ears and they are easily broken. Hard plastic floats often have tarred rope netting around them as well. Inflatable floats and foam floats are not very good for tuna longlines as they are compressible and could collapse if a fish drags them down deep. Foam floats and bullet buoys are often used on swordfish longlines, however. Plastic floats for tuna longlines should be pressure rated down to 200 to 300 m.

Hard Plastic Float Foam Float Inflatable float

Floatline with Float Flagpole

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Radio buoys

Radio buoys and radio direction finders (RDF) allow longline fishermen to have a more relaxed break while the line is soaking. Radio buoys give out signals that are picked up by the RDF on the fishing boat from as far away as 35 nm, so the fishermen can sleep while the line is soaking, knowing that they will be able to find the line later. Radio buoys require special rigging and special maintenance. Radio buoys usually come with a flotation collar made of canvas covered foam.

Radio buoy

Bait

The principle of line fishing is to lure fish to bite the bait. Therefore, bait is one of the most important factors in line fishing. The catch rate depends to a large extent on bait type, quality and size (Bach et al. 2000). Fishermen use different types of bait from their experience accumulated over the years. The type of bait is chosen with regard to the target species. Bait quality is one of the important factors, which affect the catch rate. Bait must also be suitable to the target species. What attracts the fish is the odour from the bait. As the odour gets stronger, the more it attracts fish. The quality of bait is also measured by how well it remains on the hook. In addition to the attractiveness of the smell and taste stimuli, the efficiency of bait is determined by its physical strength and ability to remain on the hook throughout the soaking time. The bait loss is more important for hooks on the bottom. Bait size is also an important factor affecting the fish size and catch rate. As bait in mid-water is more easily seen than bait on the seabed, the effects of bait size are more pronounced for pelagic or semi pelagic longline than for bottom longline. The bait size also affects the size of the fish caught, as small fish prefer small size prey because of their mouth size and ability to bite and handle the prey. Bottom set longline

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Bottom set longlines operate close to the sea bottom for demersal species such as shark,

sea beams, sea bass, goupers, snapper, cod, haddock, halibut, hake and flat fish. As the bottom longlines are set near the sea bottom, they are easily damaged by obstacles on the bottom. When using bottom longlines, the ground must be fairly regular since rocks or corals may entangle the lines and break them. Where muddy bottoms are found, the longlines are not set to remain on the bottom and are held off the seabed by floats. They can be set so that the bait is suspended at any desired distance from the bottom. In bottom longline fishing, the main concern is the selection of optimum branch lines because of the character of the fishing operation. The bottom set longlines which have the branch lines set at wider spacing catch fish better than those with the branch lines set more closely together, and they also need less bait for the same area. The length of the branch line must be selected correctly. The branch line cannot be too short because short branch lines are less effective than long branchlines. The length of the branch line is related to the hooking space and the free space of the vessel used in longline fishing. The branch lines are knotted to the mainline. They can also be connected to the mainline by using removal clips or swivels. Using swivels has many advantages in handling. The branch lines can be easily changed and stored separately and also the distance between branch lines on the mainline can be adjusted whenever it is needed. It also has the advantage in eliminating entanglements of the branch lines, thus reducing the labour of gear handling (Gabriel et al. 2005). Branch lines are mostly made of monofilament and multifilament. In some longline fisheries, particularly for catching different sharks, branch lines made of steel wire or chain are used because fibre branch lines are easily cut by the sharp teeth. Bottom longline fishing is mostly carried out at depths from 100 to 800 m. The longline fleets are set on the bottom with anchors, buoy lines, buoys and/or marker buoys at either end.

The whole view of a bottom set longline and hooking space. A mainline with a branch line

set on the bottom by buoy and anchors (Hameed and Boopendranath 2000).

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Bottom set longline

The anchor is made of stone, steel, lead or chain with a weight from 5-10 kg up to 80 kg.

The purpose of buoys is to keep the gear in a certain position with anchor. It is made of synthetic fibre with different buoyancies. The buoy line is a rope somewhat stronger than the mainline, because it must have the high strain that is often needed to pull the anchor. In the middle, buoys with buoy lines and anchors are also used in order to save time and prevent the risk of losing gear if the mainline breaks during hauling. In case the line breaks, instead of moving to the end buoy, which might be far away, the middle buoy which is close to the vessel is picked up and the hauling is done continuously after short time. The purpose of the marker buoy is to mark the ends of the longline fleet so that fishermen can easily find the longline from a distance. It consists of a pole (3-4 m long) and a weight at the bottom end to keep it floating in an upright position. Marker buoys usually carry one or two flags at the top end in order to make it more visible and a battery-light package or radar- light reflector in the marker buoy is used to identify the gear easily in darkness. In addition to the marker buoy, there are normally one or more surface floats, the main function of which is to keep the strain off the buoy line. The amount of lines depends on the capacity of the vessel, topography of the bottom, and the distribution and density of fish. Fishing is done by setting in stern, soaking, and hauling in starboard and handling gear. Before setting, baiting is done by auto baiting machines on boat or manually on land. Soaking times are different depending on the fishing operation, normally two to three hours. Hauling is done by powered machines in the starboard. Different methods are used for storing longlines. In auto longline fishing, hooks with the mainline and branch line hang on racks. Basket, tubes and wooden or plastics boxes are used for keeping hooks with branch lines.

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Drift longline

Drift longline is operated close to the surface in middle water layers for pelagic fishes such as tuna, marlin, billfish, mackerel and shark. The fishing method is similar to the bottom set longline. The setting work is done from the stern. The speed of the vessel in setting differs according to the fishing conditions, but is normally around 5-6 knots. At first, marker buoys with flags, radio buoys and light buoys are thrown in and the mainline is released. The marker buoy, light buoys and radio buoys are connected at proper intervals. In case of auto line, hooks are baited when the mainline is released. After setting, the vessel stays for six hours near the line. In hauling, the line is hauled by a powered hauler and when the branch line comes onboard the fish is removed. For traditional drift longlines, the mainline carrying the branch lines is coiled and kept in a basket. In modern large-scale drift longline, mainline is continuously pulled and kept on a powered reel or rack with branch lines.

Drift longline set in a certain water depth by buoys is applied to catch fish migrating in mid-water (Birds Australia 2006).

There are some cases that on hauling branch lines are removed from the mainline and

kept separately. But nowadays lines with branch lines are usually kept on racks after hauling (Bjordal and Løkkeborg 1996). To locate the potential fishing ground and to position the line in deep seas, it is important to know the correlation between fish distribution and sea surface temperature or the thermocline. Distribution of fish is determined by temperature and feed organisms. Thermocline is the temperature continuity layer where temperature changes rapidly with depth, between mixed surface waters and cooler deeper waters. Fish like tuna are generally found in the thermocline layer. The swimming layer of the yellow fin tuna and albacore is in the mixed layer and thermocline. Big eye tuna occupies lower layers of the thermocline and the

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cooler waters below. Information on the swimming layer of target fishes and their association with the thermocline is used by fishermen for fishing the target species. Sea surface temperature and ocean colour charts are used to locate potential fishing grounds based on the temperature preference regimes of target species and the aggregation of feed organisms in the thermal front (Hameed and Boopendranath 2000). The most common drift longline in fisheries is the tuna longline. The tuna longline was introduced by Japanese fishermen about 300 years ago and they have been a leading nation in terms of longline fisheries along with China and Taiwan. The tuna longline, like most of other longlines consists of many sets. Each set ranges from 150-400 m in length. Typical branch lines for tuna longline consist of three sections and each branch line is attached with a special snap-on metal clip to the mainline. Each set is stored in a basket. Japanese fishing boats, ranging from 200 to 800 gross tonnages in size, usually carry 350- 400 baskets of longline. The tuna longline is not only an effective fishing method but also a very labour intensive one (Gabriel, et al.2005). Mechanisation and automation for both bottom and drift longline are successfully under way. While setting, the hooks are baited by drawing them through an automatic machine. Mechanical hydraulic line haulers are now widely used in drift longline fishing. This system includes de-hooking of fish, twist removal of branch lines, hook cleaning and handling lines. This has decreased the manpower required dramatically (Hameed and Boopendranath 2000).

Vertical longline

Vertical longline is used to catch fish with a wide vertical distribution. Vertical longline is effective on steep shelves. Vertical longline is used in deep waters up to 1,200 m and in shallow areas having rough bottom conditions or in areas where fish aggregating devices are deployed. Gear construction has a little difference to drift longline. It consists of a single line with a float at one end and a weight at the other. The mainline extending across the vertical range of the swimming layer of the target species is attached to the buoy line with a swivel. Branch lines are attached to the mainline through three way swivels or snap clips, at intervals of around 2 m. The mainline is set vertically with the upper end joined to a large float and flagpoles, and the lower end is provided with a sinker. Branch lines are attached at approximate intervals to the mainline (Hameed and Boopendranath 2000). The fishing operation is similar to drift longline. When the vessel arrives at the fishing ground, the anchor, marker buoy and radio buoy with the connected end mainline are thrown overboard. The line is set over the stern when the vessel moves ahead. The hooks are baited before setting the line. After soaking for a period, the lines are hauled up using a line hauler. The soaking time depends on fish distribution and density. Fishes are removed when the branch lines come up, mainlines and branch lines are arranged and stored, and accessories are removed and stored. Bottom vertical longline combines the properties of the bottom set longline and vertical longline, using their advantages. Many hooks are attached at suitable intervals less than 2 m by polyamide monofilament lines less than a meter in length to the branch lines.

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Vertical longline set vertically by buoy and anchor to catch fish migrating across a

vertical range and connecting the branch lines to the mainline (Hameed and Boopendranath 2000).

Branch lines are designed to be directed vertically during operation by adding floats at

the top and sinkers at the bottom end. Branch lines are hung from the mainline by means of snap clips at interval of 20-25 m. The mainline is positioned at an appropriate height from the bottom by adjusting the buoyancy. When the mainline does not touch the ground the gear is particularly suitable for rough grounds (Hameed and Boopendranath 2000). Pelagic longline

Pelagic longline is normally not anchored but drifts freely in the sea. Pelagic longlines are mainly used in high seas longline fisheries for pelagic species such as sword fish, tuna, shark and salmon, but are also in coastal waters for species such as haddock during periods when the fish are feeding on pelagic prey. The fishing operation is similar to drift longline. Between the ends (marker) buoys, the mainline is suspended in the sea by floats attached at intervals. Sometimes the branch lines are weighted, but this method usually relies on the mainline sinking under its own weight to get to the required depth (Bjordal and Løkkeborg 1996).

Pelagic Longline

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Mechanisation of longline

Many studies on longline mechanisation have been conducted since the early 1960s especially in Canada, the Faroe Islands, Germany, Iceland, Ireland, Japan, Norway, Sweden, UK and USA (Bjordal and Løkkeborg 1996). The main focus of this research has been on automated baiting, hauling operation systems and line handling systems. These three systems are operated in a whole system. Two main systems have been quite successful, one is automated baiting (precise or random baiting) and the other is storage of the gear (rack or drum storage). The automated baiting is either precise baiting or random baiting. In precise baiting, a piece of bait is put on each individual hook by a baiting machine, which cuts the whole bait fish to a certain size. Precise bait size is guaranteed to be comparable to hand baited bait size. The system is operated by three fishermen. When setting is done one fisherman feeds bait fish onto the conveyor belt and the other checks that the hooks run smoothly off the rack and replaces empty racks with loaded ones. Bait is put on hooks at a certain size and speed in auto baiters. When the hook penetrates the bait, a piece of bait is cut by a mechanically driven knife and the baited hook is pulled out of the machine. This work is done at the speed of up to six EZ baiter hooks per second with a hooking spacing (branch line spacing) of 1.3 m. The captain controls the vessel and fishing operation.

Baiting and Shooting

Hauling

Handling line

Different parts of an auto longline system (Mustad Longline, A.S 2006)

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The setting speed is usually from 6-10 knots depending on the model of baiting machine

used and spacing between hooks. Hauling is done by a powered line hauler. It pulls the gear over a rail roller. When hauling, one fisherman gaffs and the other blades the fish. The line from the rail roller passes the de-hooker and the hook cleaner. Then it passes through the hauler to the twist remover and the hook separator. Twists in the branch lines are removed automatically by the twist remover by using water jet flushing. Also cleaning the lines is done at the same time as twist removal. The hook separator catches the hooks and guides them onto the rack. This is done by using magnets. When the hooks and line arrive on the rack, repair work is done. In random baiting, the line is set through the container with the mixture of pre-cut bait and water. A piece of bait is snagged to a hook randomly, when the hook passes through the bait mixture. In this case, the bait is securely fastened. Metal racks or rails are used for rack storage. The hooks are put onto the rack in sequence and branch lines and the mainline are suspended underneath. Also, drums are used either to store the mainline only by using detachable branch lines or to store the complete gear. Monofilament reel system

A monofilament reel system uses a hydraulic reel to haul and store the mainline. Blocks are used to guide the line to the reel. The reels come in sizes to suit different size boats. Small reels hold 5 to 10 nm of mainline, large single reels can hold up to 60 nm of mainline, while double reels can hold over 100 nm. Reel capacity is also governed by the diameter (3.0 to 4.5 mm) of the monofilament mainline.

Large single reel system

Line setters

Line setters, or shooters, can be used for setting continuous rope or monofilament lines. The line setter deploys the mainline at a predetermined speed, which is faster than the vessel is travelling. This gives the fish master control over depth of the mainline. The branchlines, floats and floatlines are snapped onto the mainline at regular intervals. Line setters are slightly different for rope and monofilament gear, because of the type and size of the mainline.

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Line setter (monofilament gear) (Source: http://www.lindgrenpitman.com) Advantages of longlining over trawling

Unlike trawlers, however, longliners are able to work in those areas not accessible to trawlers, particularly those which have complex sea bed topography, rough ground or are at significant depth. Longliners reduce quite considerably losses in fishing time due to weather conditions. This is because when trawling is impossible, a longliner is still able to fish. By-catch of undersized fish by longlining is fairly insignificant due to the selectivity of longlines. As for the longline, it is more selective because of its passivity. This is why those fishing grounds that are temporarily or permanently closed to trawlers because of overfishing of juveniles remain open to longliners. Longliners are more effective at scratching for scattered schools of fish, while trawlers are more productive with dense populations of fish. Fuel consumption

A significant advantage that longliners have over trawlers is the relatively low fuel consumption per unit of catch. For example, it was established that a trawler expends 0.6-1.5 tonnes of fuel per tonne of raw fish caught, while a longliner expends 0.1-0.3 tonnes (Karpenko, 1997; Makeev and Shentyakov, 1981; Pavlov and Makeev, 1987; Glukhov, 1994; Chumakov and Glukhov, 1994а, 1994b; Sorokin and Chumakov, 1995). With regards the amount of fuel used over time, the longliner spends 2.7 times less fuel every hour than a trawler (Zherebenkova and Makarova, 1990). What are the problems in longline fishing? Declining sea turtle stocks:

Sea turtle populations are declining worldwide due to human activities including: destruction or disturbance of nesting beaches; hunting for food and sale; and incidental catches related to some fishing activities such as trawling, gillnetting, purse seining and tuna longlining.

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Perceived overfishing: There is worldwide concern about the catch and use of pelagic sharks and, to a lesser

extent, marlins and other pelagic fish species by longline vessels. Some concerns are related to a belief that these species are being overfished. Seabird interactions:

The incidental take of seabirds by longline vessels (both pelagic and demersal or bottom-

set) has been widely publicised, although this mainly occurs with albatross in higher latitudes. What can be done to make longline fishing sustainable?

• Minimizing the incidental catch of unwanted bycatch species. Keeping good data in logbooks on all fishing activities, including the recording of byproduct and bycatch taken or interactions with protected species.

• Setting pelagic longline gear deeper than 100 m will reduce the incidental catch of many bycatch species (especially sea turtles).

• Setting deep, using a line setter, puts the bait in the zone where catches of albacore and bigeye (target species) will be maximised.

• Not using squid for bait on shallow-set hooks (those closest to the float and floatline) will lessen the chance of hooking sea turtles, as this is a favourite food of theirs.

• Not using a branchline under the float to target sharks. • Setting pelagic longlines at least 12 nm from a reef or island, and ensuring they drift

offshore, will minimise interactions with reef sharks (not pelagic sharks) and some turtle species, as they do not venture far from the reef.

• Using monofilament leaders (not wire) directly onto the hook will allow sharks to bite off the hook and escape.

• The bycatch of sea turtles by pelagic longlining is an issue of great concern. If a turtle is caught, steps should be taken to give it the best possible chance of survival.

Avoiding seabirds and bait loss

The issue of tuna longline gear interacting with seabirds, causing incidental takes, is an issue in some regions in longline fishing. There is a problem though at times with bait loss through seabirds attacking baited hooks as they are set. In areas where seabird interactions have occurred, mitigation measures have been developed and introduced. These measures also work to reduce bait loss, by making it difficult for the seabirds to get to the baited hooks, or getting the baited hooks to sink faster. Setting tuna longline gear at night is by far the simplest and easiest way to avoid bait loss to seabirds, as most seabirds are day feeders. However, in some fisheries the setting time is dictated by the main feeding time of the target species and night setting of the gear may result in lower catch rates.

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Depredation by toothed whales ‘Depredation’ is the term used when unwanted species such as cetaceans or sharks consume

hooked fish, while predation refers to one species preying on another. Toothed whales sometimes attack and eat tuna and swordfish that are caught on longlines. When a pod of these whales finds a longline with fish, they follow the line eating everything except the head of the hooked fish. Some dolphin species have been associated with the loss of bait from longline gear. Some whales have interacted with the longline gear itself and become caught, putting the whale at risk and damaging the gear. Given there are no foolproof mitigation measures available at present, the following measures can avoid or minimise the chance of interactions or depredation.

• Reducing vessel noise, possibly through vessel design. • Managing gear noise through its operation (turn off echo sounders when not in use,

reduce noise of deck machinery, propeller noise etc.). • Considering changes to gear and setting and hauling practices. • Considering changing fishing areas and fishing seasons. • Avoiding areas where cetaceans are known to congregate. • If cetaceans are sighted during the set, discontinue the set, haul the line, and move to

another location. • Use acoustic equipment to try to locate and subsequently avoid cetaceans. • Avoiding discarding of offal and used bait in the vicinity of fishing locations.

Conclusion

Longlining is one of the main fishing methods that holds potential for economic development in many countries and territories. The method targets the larger, deeper swimming tunas and other oceanic resources that command high prices in export markets if they are handled carefully and quality is maintained throughout the catching, processing and exporting processes. The costs for local operators to set up a longlining operation are high, but the potential returns are also great. While promoting longline fishing focus should be on sustainable and responsible fishing practices. longlining has 1.5 times more advantages than trawl and fewer drawbacks. However, it should be noted that longline fishing has the clear drawback of needing to use additional biological resources, ie. squid, fish, shellfish, etc, as bait for its hooks. This negative characteristic of longline fishing, however, is compensated for by the much more sparing fishing qualities it has in comparison with other fishing methods. Despite the few drawbacks of longline fishing, its advantages over other fishing methods are very clear. The large-scale development of the sustainable longline fishery is one of the means of optimizing the exploitation of tuna and other oceanic resources. At the same time, it is necessary to state that the development of the longline fishery must not only be aimed at increasing the size of the fleet, but also at increasing the working efficiency of existing vessels. Tunas and other oceanic resources can be caught very effectively using the longline, but remain inaccessible to the bottom trawl which is the most common fishing method. For promoting longline, it will be necessary to avoid shifting preference over to longlines entirely. It is should be borne in mind that some stocks of fish, bottom resources such as shrimps are difficult for the longline to access and their exploitation is only possible using trawl fishing gears. Therefore it is essential to ensure that only the combined use of these fishing gears will allow for the optimal utilisation of the all the resources. There should be a rational

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distribution of fishing efforts according to fishing areas and seasons and the taking into account the various biological peculiarities of the fish being exploited. References/suggested reading

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Ardill, J.D. (1984) Tuna Fisheries in the South West Indian Ocean [Electronic Version] http://www.fao.org/docrep/field/255095.htm (28-12-06) assessment and trends (in Russian). Commercial Fisheries, 1981, Vol. 3, 72p

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Bach, P., Dagorn, L. and Misselis, C. (2000) The role of bait type on pelagic long line efficiency. ICES, Copenhagen (Denmark):16p

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Strategies for Material Protection in Aquatic Environment P. Muhamed Ashraf


E-mail: [email protected] Introduction

Settlement of micro and macro and microorganisms over the submerged materials is called biofouling. If a material is immersed in aquatic environment it will experience an initial formation of biofilm. This is due to the adsorption of proteins, polysaccharides, macro and micro organic molecules over the surface. This complex nutrient rich surface attracts bacteria, fungi, diatoms and micro algae, and this layer is called biofilm [Avelelas et al 2017]. Organisms like barnacles, mussels, sponges, polychaetes, oysters etc attach over the biofilm and this results in degradation of materials or change the physico-chemical characteristics.

Aquaculture industry is coming up in India and provides cheapest protein food for the growing population and for export. The government and planners look upto aquaculture as one of the important items to meet the food security challenge of the growing population [FAO 2014]. The vast coastal line of about 8041 km, 3million hectares of reservoirs and 1.2 million brackish water resources can contribute enormously to improve the fish production through aquaculture. NFDB report of 2017-18 showed that 67% of the total fish production is coming from inland and culture sector. India’s position in aquaculture production is 2nd in the world and it plays an important role in employment, labor, exports and economy. Biofouling is the major issue in the aquaculture industry and it eats away 25% of the project cost. Biofouling of the cages increases the weight of the cages, close the lumen, blocking the circulation of wastes, and its cleaning increases the turbidity and hence affect the growth of the fish in the cages. Biofouling in the cage nets will affect the growth of the fish thereby the economic loss. Current strategies

In the shipping industry the biofouling is effectively prevented by using different coating

technologies. Initially copper oxide based coating was used. Later effective chemicals like Tributyl tin oxide (TBTO) and their analogue compounds were used for protecting the ship hulls. TBTO was effective and popular among the ship builders and boat manufacturers. TBTO was banned world over due to its accumulation in the bottom crawling organisms and due to its toxic nature. Currently new generation antifouling paints are manufactured based on self-polishing, low surface energy coatings and other new generation organic molecules. For fishing boats and other submerged materials such as pillars, dam shutters mainly employed CuO based antifouling paints are mainly employed. World over aquaculture is growing and no effective coating methods were used to prevent biofouling in the cages. Antifouling strategies in aquaculture is very sensitive issue since it directly enters into the human body. Hence it requires detailed impact assessment studies. Current methods to combat biofouling in aquaculture system is manual or mechanical cleaning, which is very labour intensive and detrimental to the fish grown in cages. Popular antifouling strategies in aquaculture cages are treating low level copper based chemical coating and it leaching the aquatic environment in fixed amount will deter the foulers. Treatments usually

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last only for one season of culture. The cost for treating the net is very high and the major problem is the disposal of the net after use. Also these types of nets are heavily coated with copper and the aquatic body will expose higher copper concentration. Different other methodologies suggested are biological control using grazers, silicon base coatings, acetic acid based coatings, cage net modification to prevent oysters and natural material principled antifouling coatings. Still these are under research stage and most of them are not suitable to aggressive marine environments. Introduction of nano technology open up the application of nano materials against biofouling organisms. Nano technological solutions

The principle of nano technology is that those materials with known properties and

functions will exhibit different behaviour and functions at nano sized state. Particles with dia 1 to 100 nm sized materials are considered as nano materials. The surface area of a unit weight materials are enormous compared to the normal molecules. The nano materials are extensively employed for solving the problems of drug delivery, sensors, catalysis, surface coating and antibacterial applications. The activity of the nano materials were very high and hence very low amounts of material be having high efficiency. Nano materials are extensively used as biocides and can be applied as antifouling agent. Nano application in aquaculture cage nets Nano copper oxide coated HDPE cage nets

Polyethylene fibres are extensively used to manufacture aquaculture cage nets. Polyethylene is nonpolar polymeric molecule and difficult to introduce the biocide over the molecule. Generally, biocide coatings were made over the cage nets using adhesives. The major disadvantages of biocides like copper oxide coating over the cage net is leaching to the aquatic environment and disposal of nets after use. The major advantage of nano materials as biocide very less quantity used, increased surface area of exposure and exhibit higher efficiency. Since polyethylene is nonpolar we have undertaken different methodology to make the polyethylene surface polar. The surface was coated with in situ synthesised polyaniline, a conducting polymer. Over this surface nano copper coated and their characteristics were studied. Uniform coating of polyaniline and copper was showed by Scanning electron micrograph and Atomic force micrographs. The formation of the biocide was verified by analysing FTIR spectra (Ashraf et al 2017). Polyaniline coated polyethylene showed IR absorption was shifted from 1362 to 1396 cm-1 indicating the attachment of polyaniline over PE. Quinanoid peak of NH4+/NH+ in polyaniline was exhibited at 1047/1161 cm-1 and the same was shifted further to 1070 / 1179 cm-1 due to nano copper coating over polyaniline.

The field evaluation of the cage net showed the excellent biofouling resistance after 90

days exposure in the estuarine environment. The experiment was repeated by constructing a cage with treated and control panels and exposed in the Vizhinjam coast for 7 months (fig 1). The fishes grown in the cages and controlled environments were compared and exhibited significant difference in growth was shown.

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Fig. 1. Control and treated net after 7 months exposure in the marine environments

Different tests to verify the biofouling resistance are mentioned in detail by Ekbalad et al

2008. Deterrence of biofouling organisms to the treated surface was tested by cyprid assays. The treated surfaces were exposed to the testing organisms in natural or artificial seawater at controlled environments. Callow et al 1997 described assays using microorganisms like Ulva zoospore over the treated surface. The exposed surface in controlled environment were evaluated based on the attachment of spores. Callow et al (2002) and Schultz et al (2000) described about the determination of adhesive strength using a calibrated flow channel. Diatom assays were generally carried out using Navicula perminuta (Pettitt et al 2004) by suspending the treated surface in artificial seawater containing chlorophyll a 0.30 ug ml-1. After 2 h exposure the surface was evaluated for the adherence and deterrence of organisms. Antibacterial property of the biocide treated surfaces were evaluated using two marine bacteria viz Cobetia marina and Marinobacter hydrocarbonoclasticus (Akesso et al 2009: Ista, et al 1996). The former bacteria are considered first settled microbes over marine exposed surfaces. The measurement was carried as per the protocols described by Akesso et al 2009. Nano copper oxide incorporated hydrogel

Hydrogels are considered eco-friendly and hydrophilic in nature. Hydrophilic nature of polyethylene glycol hydrogel will deter the adsorption of proteins and this will reduce the attachment of microorganism and biofilm formation. Thereby reduced accumulation of macro foulers. The major disadvantage of hydrogel is that it will degrade after sometime and susceptible for biofoulers attack. We tried to synthesise with more efficient hydrogel by incorporating nano biocide (Ashraf PM 2019). The problem of non-polar nature of polyethylene was overcame by synthesising nano copper oxide incorporated hydrogel in situ by microwave method. The hydrogels were strongly bonded over the cage net which was evidenced by SEM, FTIR and AFM studies. Field evaluation was carried out to understand the biofouling resistance of the coating

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and showed 53% more efficient than control. The mechanism was explained due to the formation of semi hydrophilic in nature, defect free, compact structure and the nano copper oxide acted as a point source to deter the attack of micro and macro organisms. Mixed charged Zwitterionic polymeric hydrogel

Polyethylene glycol hydrogel is having less surface energy difference with surrounding water and this will increase the probability of adsorption of foulers over the surface. A new class of hydrogels considered are environmentally safe, zwitterionic hydrogel polymers, which is having equal number of cations and anions and super hydrophilic. It was generally synthesised using S, carboxy or phosphor betaines. Mohan and Ashraf (2019) synthesised a nano silicon oxide incorporated mixed charged polymeric hydrogel through microwave method over aquaculture cage nets. Mohan and Ashraf [25] synthesised a nano-sized SiO2-incorporated poly (N-isopropylacrylamide-co- 2-(methacryloyloxy) ethyl]- Trimethylammonium / 3-sulfopropyl methacrylate) mixed-charged zwitterionic polymeric hydrogel in situ over a polyethylene aquaculture cage netting material treated with polyaniline. The SEM, AFM and FTIR studies confirmed the formation of hydrogel. Its efficiency was tested by exposing in the estuarine environments and showed the biofouling resistance at two months.

Conclusion

Aquaculture industry is facing severe biofouling problem and its management incurs huge expenditure. Current technologies are sustainable due to its low impact on environment. Nano technology offers excellent solution to combat biofouling and the technology needs further refining. The advantage nano materials are low in quantities for application and increased efficiency.


Avelelas, F., Martins, R., Oliveira, T., Maia, F., Malheiro, E., Soares, A.M., Loureiro, S. and Tedim, J. (2017)

Efficacy and ecotoxicity of novel anti-fouling nanomaterials in target and non-target marine species. Marine biotechnology, 19(2), pp.164-174

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FAO (2004) The state of World Fisheries and aquaculture. Rome FAO, 2004, 153

Ashraf PM, K.G. Sasikala, Saly N. Thomas, Leela Edwin (2017) Biofouling resistant polyethylene cage aquaculture nettings: A new approach using polyaniline and nano copper oxide. Arabian Journal of Chemistry. http://dx.doi.org/10.1016/j.arabjc.2017.08.006

] Ekblad, T., Bergstrom, G., Ederth, T., Conlan, S.L., Mutton, R., Clare, A.S., Wang, S., Liu, Y., Zhao, Q., D’Souza, F. and Donnelly, G.T. (2008) Poly (ethylene glycol)-containing hydrogel surfaces for antifouling applications in marine and freshwater environments. Biomacromolecules, 9(10), pp.2775-2783

Callow, M.E., Callow, J.A., Pickett-Heaps, J.D. and Wetherbee, R. (1997) Primary adhesion of enteromorpha (chlorophyta, ulvales) propagules: quantitative settlement studies and video microscopy 1. Journal of Phycology, 33(6), pp.938-947. `1

Callow, M.E., Jennings, A.R., Brennan, A.B., Seegert, C.E., Gibson, A., Wilson, L., Feinberg, A., Baney, R. and Callow, J.A. (2002) Microtopographic cues for settlement of zoospores of the green fouling alga Enteromorpha. Biofouling, 18(3), pp.229-236

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Schultz, M.P., Finlay, J.A., Callow, M.E. and Callow, J.A. (2000) A turbulent channel flow apparatus for the determination of the adhesion strength of microfouling organisms. Biofouling, 15(4), pp.243-251

Pettitt, M.E., Henry, S.L., Callow, M.E., Callow, J.A. and Clare, A.S. (2004) Activity of commercial enzymes on settlement and adhesion of cypris larvae of the barnacle Balanus amphitrite, spores of the green alga Ulva linza, and the diatom Navicula perminuta. Biofouling, 20(6), pp.299-311

Akesso, L., Pettitt, M.E., Callow, J.A., Callow, M.E., Stallard, J., Teer, D., Liu, C., Wang, S., Zhao, Q., D'Souza, F. and Willemsen, P.R. (2009) The potential of nano-structured silicon oxide type coatings deposited by PACVD for control of aquatic biofouling. Biofouling, 25(1), pp.55-67

Ista, L.K., Fan, H., Baca, O. and López, G.P. (1996) Attachment of bacteria to model solid surfaces: oligo (ethylene glycol) surfaces inhibit bacterial attachment. FEMS Microbiology Letters, 142(1), pp.59-63

Muhamed Ashraf, P. (2019) Nano CuO incorporated Polyethylene Glycol Hydrogel Coating over Surface Modified Polyethylene Aquaculture Cage Nets to Combat Biofouling. Fishery Technology. 56 (2019): 115 – 124

Ahana Mohan and P Muhamed Ashraf (2019) Biofouling Control Using Nano Silicon Dioxide Reinforced Mixed- Charged Zwitterionic Hydrogel in Aquaculture Cage Nets. Langmuir. 35 (12), pp 4328–4335. DOI: 10.1021/acs.langmuir.8b04071

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Environmental impact assessment of chemical protectants used in fishing industry

S. Chinnadurai ICAR- Central Institute of Fisheries Technology, Kochi


Introduction

Any surface, immersed in seawater is subjected to the settlement of marine organisms

(bacteria, algae, mollusks), known as fouling or biofouling. This unwanted colonization has serious impacts, in particular for the fishing industry, with deterioration of the surfaces, increased roughness, increased weight, increased fuel consumption, and loss of maneuverability of the vessels. Fouling growth can interfere with the operation of submerged equipment, impose increased loading stresses and accelerate corrosion on marine structures, and adversely affect the performance of ships by increasing hydrodynamic drag, which necessitates the use of more power and fuel to move the vessel through the water. Marine species may also be introduced into non-native environments through ship transport. Marine biofouling is a worldwide problem, costing billions of dollars per year in transportation.

The corrosion of vessels and structures immersed in the sea also pose significant

economic and operational costs. The marine corrosion and biodegradation of materials can compromise the operation and structural integrity of vessels, structures and other immersed equipment. Control of fouling and corrosion would generate significant savings in both the maintenance and operational expenditure of maritime platforms and equipment. Biofouling has been and currently is globally important due to its environmental and significant economic impact; the estimated cost for transport delays, hull repair, cleaning and general maintenance is 150 billion USD per year (Schultz, 2007). Marine fouling can increase a ship’s fuel consumption by 10–20%, besides, increasing sailing time with its attendant costs. Marine fouling on stationary structures adds mass and surface area, thereby increasing the force of wave action. Marine fouling inside pipes used by seaside power plants, roughens the surface (increases friction), reduces inside diameter, and increases the power requirements for pumping. In very severe cases, marine fouling can block completely the flow of water through pipes. Even microscopic fouling (bacterial films) can interfere with the effectiveness of power plants by reducing heat transfer through heat exchangers.

Antifouling (AF) coatings have been developed to prevent the settlement of fouling

organisms. The earliest techniques proposed were pitch, tar, wax, heavy metals (lead), or toxic (arsenic-based) coatings. In the mid-1960s, self-polishing AF paints incorporating tributyl tin oxide (TBT-based compounds) were the first to show durable efficiency with a modest cost of production. TBT acts as a broad-spectrum biocide and can be incorporated into paints in such way that it is released from the coating and effectively inhibits fouling on a ship hull up to five years. However, in the late 1970s, the adverse effects of TBT became apparent. Several studies indicated that TBT-based compounds had adverse effects on aquatic life and more specifically on non-targeted fouling organisms such as bivalve molluscs, due to its high persistence and toxicity.

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The impact of TBT on marine organisms urged many governments to restrict its use. France was the first country to ban the application of TBT-based AF paints on ships less than 25 m long in 1982. In October 2001, the International Maritime Organization took into account the adverse effects of TBT on the marine environment. An order was issued banning the use of this type of biocide in the manufacturing of AF paints from first January 2003 and the presence of these paints on ship surfaces from first January 2008. However, toxic coatings, especially regarding the tributyltin (TBT) era, were not without complications, of which we are now well aware. We are still using copper and to some extent, less favourable biocides on most ship hulls or other marine constructions.

The chemicals used in fishing technology for material protection is very disturbing to the sustainability of the marine ecosystem. The major disadvantages of use of chemicals are their instability, leaching, and high surface activity which lead to toxic reactions in marine organisms or environment. The restriction on the use of TBT led to a renewed use of copper-based paints and/or the use of new paints incorporating high levels of copper. However, copper (and other metals) may also pose problems for the environment. Copper based antifouling strategies were extensively employed as biocides in antifouling management by different workers due to its high efficiency against material degradation. But several researchers raised concern regarding the safety and toxicity of the copper based biocides. It has been well documented that maintenance of vessels painted with copper based biocidal coatings can also contaminate inshore environments (Schiff et al., 2004 and Turner et al., 2008). Study of Environmental Impact Assessment (EIA) system is vital to conform socio-economic development projects to environmental safety and thereby ensure sustainable economic development. It also helps the planning and management to take long-term measures for effective management as well as environment conservation. Widely used Chemicals in fishing industry

Chemicals have very diverse applications and play an important role in the industry-

dominated human society. Some chemicals are critically important for marine applications especially as anti-fouling, anti-corrosive and wood preservative agents.

Anti-corrosive chemicals and their mechanisms

There is a great demand for functional anti-corrosion coatings as a result of the

tremendous degradation and losses to metallic structures due to corrosion. Chromium-based compounds and zinc have historically been the most common coating materials, but due to stringent health, safety, and environmental rules and regulations by many governmental agencies around the world, the usage of the former had declined progressively in the last two to three decades, while the application of zinc as a coating material is also significantly discouraged due to large price fluctuations. Self-healing anti-corrosion coatings can be a very beneficial alternative for the long-term protection of such structures. The term ‘self- healing’ is defined as self-recovery of the initial properties of the material after destructive action of the external environment. It should also be noted that the hindrance to the corrosion phenomenon by the protective coating is the most important criterion for calling the performance of the coating of self-healing as this automatically recovers the initial properties of the coating. There are many mechanisms by which anti-corrosion coatings operate, but generally these can be divided into three barriers:

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barrier creation between substrate metallic materials and the surrounding environments; the inhibition of the corrosion process; and the coating acting as a sacrificial material.

Corrosion science involves the study of electrochemical processes taking place at electrodes. An electrode is essentially the boundary between a solid phase (i.e., metal) and a liquid phase (i.e., aqueous environment), and the corrosion processes take place across the phase boundary. The basic wet corrosion cell consists of four essential components: an anode, a cathode, an electrolyte, and connections. The first concept of corrosion control is that removal of any of these four components of the simple wet corrosion cell will naturally stop the corrosion reaction. From an engineering point of view, the major point of interest in corrosion science and engineering is the kinetics (or the rate) of corrosion reactions. The principal goal for studying corrosion reaction kinetics is to develop an empirical relationship that permits the prediction of corrosion rate under conditions that are different from those employed in the laboratory and to determine the mechanism of the overall corrosion process. Anti-fouling chemicals

Antifouling coatings are used to prevent the settlement and growth of marine organisms on

structures immersed in the ocean. The ocean is swarming with the planktonic forms of barnacles and other sessile marine organisms. Any object immersed in the ocean is rapidly colonized by a wide variety of organisms ranging from microscopic bacteria and algae to barnacles, tubeworms, bryozoa, oysters, and mussels. The accumulation of microscopic organisms is called microfouling while the accumulation of larger organisms is termed macrofouling. The settlement and growth of these organisms (collectively referred to as marine fouling) have significant adverse effects on structures in the marine environment. Copper-based antifouling coatings have been successfully used since the early days of wooden sailing ships when they were applied as sheets of pure copper metal or as overlapping copper nails. Modern copper-based antifouling coatings rely upon cuprous oxide as the principal toxic agent and contain up to 75 vol.% cuprous oxide.

Antifouling paints, that continuously release one or more biocides through the paint surface has been the primary method of fouling prevention on ships and other marine vessels for more than a century. However, by necessity, antifouling biocides are toxic, and can cause secondary environmental impact if the biocide does not quickly degrade after release and maintains its toxicity and bioavailability. Many antifouling biocides, such as mercury, arsenic, DDT and tri-organotin compounds, have been widely banned, and others, including copper, continue to be under scrutiny (Schiff et al., 2007). Chemicals for wood preservation

Wood preservatives are substances applied to wood to protect it from degradation due to

biological agents and different environmental conditions. Initially, natural wood preservatives like neem oil, sardine oil and cashew nut shell liquid were more prominently used. Later they were replaced with chemical preservatives. Over the past century, a variety of wood preservative methods including pressure treatment have been developed, that introduce a small amount of protective preservative into the wood cells (Edwin and Thomas, 2000). Preservatives that are widely used for pressure treatment of wood can be classified as oil borne, water borne (fixed and leachable) and solvent type. The water borne preservatives have largely replaced the oil borne

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preservatives like creosote for aquatic use, on environmental and human health considerations. Creosote was in use from 18th century for the protection of railway sleepers. The water borne preservatives include chromated copper arsenate (CCA), chromated copper boron (CCB), ammoniacal copper arsenate (ACA), acid copper chromate (ACC), ammoniacal copper zinc arsenate (ACZA) and ammoniacal copper quat (ACQ). Solvent type preservatives include pentacholorophenol and copper naphthanate. Chemical transformations in aquatic systems

Chemicals entering into an aquatic compartment from various sources, including from

antifouling and anticorrosive paintings on boats will be exposed to a highly dynamic physical and chemical environment that leads to several transformations that will change their pristine physicochemical properties. Metals and metal compounds raise issues not generally encountered with organic chemicals. Metals are neither created nor destroyed by biological and chemical processes; rather they are transformed from one chemical species to another. These transformations, including dissolution, aggregation and sedimentation, are dependent on both physicochemical properties of the chemicals and those of the environment into which they were released. Metal elements and some inorganic metal compounds are not readily soluble and as a result toxicity tests based on soluble salts may overestimate the bioavailability and potential toxicity of these substances. Some metals are essential elements at low levels (e.g., copper, chromium, and zinc) but toxic at higher levels; while others which are non-essential (e.g., lead, arsenic, and mercury) bioaccumulate and are toxic. Many organisms have developed mechanisms to regulate accumulation of some metals to some extent, especially for essential metals. Each environmental form of the metal has its unique fate/transport, bioavailability, bioaccumulation, and toxicity characteristics (Zhang et al, 2018). Environmental Impact Assessment of chemical contaminants (EIA)

Every anthropogenic activity has some impact on the environment. It is necessary to take

up the activities for food, security, and other needs. There is a need to harmonize developmental activities with environmental concerns. Environmental impact assessment (EIA) is one of the tools available to planners to achieve this goal. It is desirable to ensure that the development options under consideration are sustainable. In doing so, environmental consequences must be characterized early in the project cycle and accounted for in the project design. The objective of EIA is to foresee the potential environmental problems that would arise out of a proposed development and address them in the project plan and designing stage. It integrates the environmental concerns in the developmental activities right at the time of initiating for preparing the feasibility report, which will enable the integration of environmental concerns and mitigation measures in project development. It can often prevent future liabilities or expensive alterations in project design. It is a policy and management tool for both planning and decision making. It assists in identifying, predicting, and evaluating the foreseeable environmental consequence of proposed development projects.

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Objective of EIA:

The objectives of EIA are (i) to identify, predict and evaluate the economic, environmental and social impact of development activities (ii) to provide information on the environmental consequences for decision making and (iii) to promote environmentally sound and sustainable development through the identification of appropriate alternatives and mitigation measures.

The EIA is defined as: a policy and management tool for planning and decision making which assists to identify, predict, and evaluate the foreseeable environmental consequences of proposed developmental projects, plans, and policies. The outcome of an EIA study assists the decision maker and the general public to determine whether a project should be implemented or not. EIA does not make decisions, but it is essential for those who do. Environment Impact Assessment Methodologies

The methods used to prepare and evaluate environmental impact assessment depend on the purpose and role of the assessment in determining public policy. While a rather simple and obvious connection must exist between purpose and methodology. It tends to highlight the fact that environmental impact assessment is used for a variety of purposes and therefore requires different methodological approaches. They are discussed below. Leaching studies of chemical protectants

Leaching tests are frequently used to assess the potential risk of a waste to release organic and inorganic contaminants into the environment. Several leaching protocols have been developed with each differing in terms of leaching solution used, liquid-to-solid ratio, contact time, number of extractions and other testing parameters. The most commonly used leaching protocol is the US EPA Method 1311 for the Toxicity Characteristic Leaching Procedure (TCLP) (US EPA, 1992), which is designed to simulate leaching conditions in municipal solid waste landfills using a laboratory setup. For the evaluation on leaching of copper from the nano copper oxide treated polyethylene (PE) webbings can be assessed by modified ASTM D 1239 leaching method (Hingston et al, 2001). Acute (Single-Dose) Toxicity Studies

Acute toxicity studies are conducted to evaluate the effects of a single substance. Usually each animal receives a single dose of the test substance in this study design. On rare occasion, repeated doses may be administered, but in any event, all doses are administered within 24 hours or less. Historically, a primary objective of acute toxicity testing was to determine an LD50 dose, or that dose which would be lethal to 50% of the animals treated (OCED 202, 2004). Repeated and Chronic toxicity test

Chronic toxicity is defined as adverse effects occurring after the repeated or continuous administration of a test sample for a major part of the life span. Chronic toxicity occurs as a result of a repeated daily exposure to a chemical. The objective of a chronic toxicity study is to determine the effects of a substance following prolonged and repeated exposure. However, for

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this longer duration study, the number of animals per treatment group are larger to account for possible losses over the course of the study and to improve statistical power. Depending on the nature of the chemical, duration of exposure and the results in subacute/subchronic toxicity tests, chronic toxicity may be sufficiently addressed through a risk assessment (OCED 211, 1998). Histopathological investigation

Histopathology is the study of the signs of the disease using microscopic examination of a biopsy or surgical specimen that is processed and fixed onto glass slides. To visualize different components of the tissue under a microscope, the sections are dyed with one or more stains. The aim of staining is to reveal cellular components and counter-stains are used to provide contrast. Hematoxylin-Eosin (H&E) staining has been used by pathologists for over a hundred years. Hematoxylin stains produce different colours in different organs, which make ease of identification of damage occurred in the cells (Fox, 2000). Oxidative stress analysis using biomarkers

The biomarkers that can be used to assess oxidative stress have been attracting interest because the accurate assessment of such stress is necessary for investigation of various pathological conditions, as well as to evaluate the toxicity of chemicals. Assessment of the extent of oxidative stress using biomarkers is interesting from a physiological study. The markers found in blood, urine, and other tissues provide information of oxidative stress which can be assessed by antioxidant defence system (Burton, 2011).

Toxicity of chemicals used as an anticorrosive and biofouling compound

Toxic effects of various chemicals such as Nickel, Cerium, Copper, Silicon, Iron, Zinc,

Arsenic, used for corrosive and fouling resistance were evaluated toward ecologically important species such as algae, molluscs, crustaceans and fishes. For all these species, it was found to be severely toxic since it affects their growth even at very low concentrations. Effect on algae

Copper was found to be toxic for some algae. It can inhibit growth of Chlorella vulgaris and

Dunaliella tertiolecta. Moreover, the photosynthetic activity can be blocked in Chlorella pyrenoidosa and visible lesions appear in macroalgae which was exposed to copper. Similarly, Irgarol shows highly significant toxicity in tests against several seaweeds. Also, the toxicity towards periphyton photosynthesis and for algal reproduction and for growth of Selenastrum capricornutum and Enteromorpha. (Alzieu, 2000). Effect on invertebrates

Molluscs are moderately sensible to copper oxides when concentrations are less, whilst

copper (II) chloride has no effect on the larvae of Crasoostrea gigas at the lower concentration during their embryonic development. Irgarol also showed the least toxic biocide on the embryonic development and the larval growth development of Mytilus edulis and Perna lividus.

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However, CCA constituents, Cu was found to be more lethal to the clam of Villorita cyprinoides (Sreeja, 2008). Effect on crustacea

Copper can kill the different crustacean species exposed more than 48 h. Larvae are more

sensitive than adults. Investigation shows that the antifouling herbicide Irgarol 1051 lethally effects on larval and adult grass shrimp Palaemonetes pugio. Furthermore, Zinc pyrithione is toxic to juvenile Elasmopus rapax and toy shrimps Heptacarpus futilirostris even at low concentration. In many toxicology study of ZnPt on crustacean appears to be extremely toxic for the mysid shrimp and less toxic for Daphnia magna and Tigriopus japonicas (Alzieu, 2000). Effect on fishes

Copper is lipophilic and shows only a slight tendency towards bioaccumulation. Exposure

of copper reduces survival of Pagrus fish at a low concentration. Zinc pyrithione (ZnPT) is toxic to Japanese medaka fish Oryzias latipes and causes teratogenic effects, such as spinal cord deformities in embryos and on larvae of zebra fish Brachydanio rerio at very low concentration. Moreover, ZnPt is highly toxic to red sea bream Pagrus major since the secondary lamellae of the gill filaments of this fish were heavily damaged after exposure to this antifoulant (Mochida et al., 2006). Environmental Legislation:

The first comprehensive environmental legislation (Section 102) in United States came

into force on 1st January 1970 in the form of National Environmental Policy Act (NEPA). In India, the environmental impact assessment was started in 1976-77, when the Planning Commission asked the Department of Science and Technology to examine the river valley projects from environmental angle. This was subsequently extended to cover those projects, which required ap-proval of the Public Investment Board. Then the Govt. of India enacted the Environment (Protec-tion) Act on 23rd May 1986 to achieve the objective the decision that were taken is to make envi-ronmental impact assessment statutory. The Ministry of Environment and Forests issued a Notification on 27th January, 1994 making EIA statutory for 29 specified activities falling under sectors such as industries, mining, irrigation, power and transport etc. After following the legal procedure, a notification was issued on 27th Jan 94. 10th April, 1997 and 27th Jan 2000, making environmental impact assessment statutory for 30 development projects (Schedule I), the mandatory EIA clearance procedure started. Current program implementation and research activities

Part of the implementation of EPA’s water quality program is through the development of

total maximum daily loads (TMDLs). A TMDL is the concentration of a chemical, or other pollutant, which can be added to a water body without causing the water body to exceed the concentrations needed to maintain its uses (e.g., swimming, fishing, drinking, aquatic life habitat, etc.). This concentration of the TMDL is then partitioned among all of the sources of the chemical to determine how much each source can discharge to the water body in question. TMDLs must be developed for all waters determined to be impaired. Metal is one of the principle reasons for

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water bodies in the US to be listed as having impaired water quality. Other contaminants in the top 10 include: mercury, pathogens, sediment, metals (not Hg), nutrients, oxygen depletion, pH, biological integrity, temperature, habitat alteration. The ranking specifically for metals (not Hg) puts copper, lead, selenium, and zinc in the top tier of water impairments due to metals (USEPA, 2006). Conclusion

Considering the present situation, it can be assumed that with the further advancement of

the fishing industry in India, particularly in systems undergoing intensification, the applications of chemicals would be increased. However, policy makers, researchers and scientists should work together in addressing the issues of chemicals used in fishing technology with the view to decrease the negative impacts. Therefore, both the government and non-government organizations should take initiative for better understanding of chemical uses in fishing technology. References/suggested reading Almeida, E., Diamantino, T.C., de Sousa, O. (2007) Marine paints: the particular case of antifouling paints.

Prog. Org. Coatings 59:2–20. http://dx.doi.org/10.1016/J. PORGCOAT.2007.01.017

Alzieu, C. (2000) Environmental impact of TBT: the french experience. Sci. Total Environ. 258: 99–102. http://dx.doi.org/10.1016/S0048-9697(00)00510-6

Ashraf, P.M., Sasikala, K.G., Thomas, S.N. and Edwin, L. (2017) Biofouling resistant polyethylene cage aquaculture nettings: A new approach using polyaniline and nano copper oxide. Arabian Journal of Chemistry. http://dx.doi.org/10.1016/j.arabjc.2017.08.006

Edwin, L. and Thomas, S.N. (2000) Effect of creosote and copper-chrome-arsenic (CCA) treatments on the compressive strength of haldu wood (Adina cordifolia Benth & Hook). Fish. Technol. 37: 1-4

Fox H. (2000) Is H&E morphology coming to an end? British Medical Journal. 53:38

Hingston, J.A., Collins, C.D., Murphy, R.J. and Lester, J.N. (2001) Leaching of chromated copper arsenate wood preservatives: a review. Environmental Pollution, 111(1):53-66

Mochida, K., Ito, K., Harino, H., Kakuno, A., Fujii, K. (2006) Acute toxicity of pyrithione antifouling biocides and joint toxicity with copper to red sea bream (Pagrus major) and toy shrimp (Heptacarpus futilirostris). Environ. Toxicol. Chem. 25, 3058–3064. http://dx.doi.org/10.1897/05-688r.1

OECD 202, 2004. OECD Guideline for Testing of Chemicals. ‘Daphnia sp., Acute Immobilisation Test’

OECD 211, 1998. OECD Guideline for Testing of Chemicals. ‘Daphnia magna Reproduction Test’

Quigg A, Chin W, Chen C, Zhang S-J, Jiang Y, Miao A. (2013) Direct and Indirect Toxic Effects of Engineered Nanoparticles on Algae: Role of Natural Organic Matter. Sustain Chem Eng 1:686–702. doi:10.1021/sc400103x

Schiff K, Diehl D and Valkirs A (2004) Copper emissions from antifouling paint on recreational vessels. Mar Pollut Bull, 48: 371–377

Schiff K, Brown J, Diehl D and Greenstein D. (2007) Extent and magnitude of copper contamination in marinas of the San Diego region, California, USA. Mar Pollut Bull, 54: 322–328

Schultz M. P. (2007) Effects of coating roughness and biofouling on ship resistance and powering. Biofouling, 23: 331 —341

Sreeja, A. (2008) Chromated copper arsenate (CCA) treatment for rubber wood and its impact on the aquatic biota. Thesis submitted to the Cochin University of Science and Technology, Cochin, 206 p

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Turner A, Fitzer S and Glegg G. A. (2008) Impacts of boat paint chips on the distribution and availability of copper in an English ria. Environ Pollut, 151: 176–181

US EPA, 2006. Environmental and Economic Benefit Analysis of Final Revisions to the National Pollutant Discharge Elimination System Regulation and the Effluent Guidelines for Concentrated Animal Feeding Operations. U.S. Environmental Protection Agency, Washington, DC. EPA-821-R-03-003

Graham J. Burton (2011) Oxidative stress. Best Practice & Research Clinical Obstetrics and Gynaecology 25: 287–299

Zhang W, Xiao B,and Fang T. (2018) Chemical transformation of silver nanoparticles in aquatic environments: Mechanism, morphology and toxicity. Chemosphere, 191:324-334. doi: 10.1016/j.chemosphere.2017.10.016

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Resource Conservation in Estuarine Set Bag Net Fishery M.P. Remesan



Estuarine set bag net (ESBN) also known as stake net or stow net is one of the important

fishing gears supporting livelihood for several thousands of people in the artisanal fisheries sector around the world. In India, ESBN are operated in the estuarine zones of several rivers, lakes and backwaters wherever the tidal current is strong. The net is set against the current using poles fixed at the bottom (Fig.1) or using floats and anchors. The net is considered as a non-selective and destructive fishing gear as it capture juveniles and post larvae of most of the aquatic organisms. Major share of catch from bag nets are often dried and sold as most of the fishes caught are smaller in size. Due to the above reason ESBN is banned or restricted seasonally in several places. In states like West Bengal mosquito netting is used for cod end fabrication resulting in the capture of the larvae and juveniles of commercially important fishes.

Fig.1 A. Stake nets set in a row. B. Illustration of stake net

Fig. 2. Bag nets set using outrigger canoes in Hooghly

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Design of the net

Two bag nets are set on two sides of a canoe using outriggers and poles fixed in the bottom (Fig.2). In addition to the main stakes, auxiliary stakes of smaller diameter obliquely placed as props are tied to the main stake for additional strength (Boopendranath, and Shahul Hameed, 2010).

It is a passive fishing method and the principle capturing is by filtering the organisms which drift with the tide. Stakes are fixed in series at about 4.5m distance between by 6-7 people and two canoes (Pauly, 1991).It is a conical bag net with long tapering body with more than 30 m length. Mouth of the net is fabricated with relatively large meshes of 150-200mm and it gradually reduce to 10mm or less towards the codend (Fig.3). Mosquito net like webbing is used for the codend fabrication in the stationary bag nets operated in Hooghly river, West bengal. Loops were provided at the four corners to facilitate bunching of a few meshes in the adjacent pieces of netting and for tying to the stakes. Usually, areca nut tree trunks are used as stakes.

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Fig. 3. Design of stake net from Cochin (source: Boopendranath & Shahul Hameed, 2010)

Fig. 4. Design of a bag net from Hooghly

Operation

Net is usually set at the onset of ebb tide. Codend of the net is closed and is tied to one of the stakes. A float is also tied to the codend to identify the location. The loops in the lower frame rope are attached first to the main stakes by a rope and pushed down using a forked pole. When the net is hauled up the lower loops are lifted by pulling the rope. The net is then shifted to the canoe and brought to the shore. Hauling is done towards the end of the ebb tide, when the tidal current is weak.

Usually fishing is done for 10 in a month and it starts 2-3 days before the new moon or full

moon and lasts 2-3 days after thefull or new moon. The nets are operated twice a day during these period in the forenoon and after noon.

Prawns constitute major share of the catch. Metapenaeus dobsoni, M. affinis and Fenneropenaeus indicus are the components in the descending order. Crabs and juveniles of finfishes also contribute to the catch.

Stationary bag nets are operated in the freshwater and brackish water zones of Hooghly

are long funnel shaped net made of polyethylene twines with very small mesh size (10mm or less) in the cod end. In some places material used for making mosquito net is used for fabrication the cod end which prevents the escape of even the fish larvae (Fig.5).

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Bag nets are set usually during full moon and new moon period, when the velocity of tidal current is strong. Rains in the upper stretch also bring strong water flow which is essential for the success of operation. Net is set either in the bottom (duvo benthi) or on the surface (basa benthi) supported from a canoe using two bamboo poles and anchors. Catch is removed and it is again set in the opposite direction to once again face the returning tidal current. Stationary bag nets are the prominent non-selective fishing gear used in the estuaries. The bag net in Hooghly is more than 25m long, 7 m wide at the mouth portion with long wings of about 10 m length and 2 m width. The net is made of polyethylene with 200 mm mesh size in the front and sometimes 2 mm for the cod end (Remesan et al, 2009). Study by CIFT revealed that incidence of hilsa juveniles are more when the net is operated as surface set

Fig. 5. Bag net codend made of mosquito netting

More than 90% of the bag net catch is constituted by juveniles of almost all finfish and shellfish species in the system (Fig.6). Destruction of juveniles is maximum during the winter migratory bag net fishery in the lower zones when number of bag netters from other place aggregate near the river mouth and operate the nets till the end of winter season. According to the fishermen, landings are high during this 4-5 months period.

Fig. 6.Catch from a bag net in Fraserganj, West Bengal

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Fig. 7. Juveniles dominated by hilsa in bag net catches in Narmada, Gujarat and pomfret juveniles in the bag nets at Fraserganj, West Bengal

Bag net operations are generally carried out from the end of October to mid February.

However, in certain pockets of Hooghly estuary, bag nets are operated throughout the year. In many places bag nets, poles and anchors are lifted during monsoon periods for facilitating drift gill net fishing for hilsa. Bag net catch is constituted mainly by about 30 species of which more than 90% is composed of juveniles of commercially important fishes, including hilsa. Priced items like shrimps, threadfins, Bombay duck, etc. are sorted and the remaining part is sent for drying. In the lean period 30-40% of the catch from bag net is often discarded due to uneconomic size and absence of buyers. Reports say that prawn landing in Hooghly estuary is declining year by year due to exploitation of undersized prawns. Catch statistics of Hooghly estuary indicates that hilsa catch has drastically declined during recent years.

There is no reason to use mosquito net type webbing for the codend of bag nets,

especially when it is set in the surface. All mosquito net type netting used for bag net cod end should be immediately replaced with polyethylene netting with at least 10-15mm mesh size. Considering the importance of hilsa fisheries, the Government of West Bengal should strictly enforce legal minimum mesh size for bag net codend, as the first step. Similarly bag net fishing in the nursery grounds of hilsa should be prevented during the peak breeding season. Bag net fishing can be permitted only in the lower reaches and slowly it should be phased out from other places. Buyback scheme or alternate employment options may be explored to phase out the non-selective fishing gears like bag nets from the traditional hilsa breeding grounds to improve the landings of hilsa and other fishes.

Several attempts have been made to improve the selectivity of set bagnets. Jisha, et al

(2017) carried out length frequency analysis of fishes in the stake nets operated in Cochin, Kerala and reported that 80% catch is juveniles. Amrutha et al (2017) tried T45 mesh windows at throat and belly of set bag net in West Bengal to reduce bycatch. Kathavarayan et al (2002) reported the reduction in landings of juvenile fishes in bagnet codend made of square mesh with mesh size of 20mm bar. Development of jelly fish excluder device for stake net has been attempted by Manojkumar et al. (2017).

CIFTs Intervention

In an attempt to reduce the landings of hilsa juveniles in the stationary bag nets ICAR-Central Institute of Fisheries Technology, Kochi in collaboration with ICAR-Central Inland Fisheries Research Institute, Barrackpore has taken up a project. In stationary bag nets, two types

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of bycatch reduction devices (BRDs) were tried in selected centers in Hooghly (Tribeni, Godakhali, Diamond harbour and Fraserganj), West Bengal; Narmada river (Bhadbhut, near Bharuch) in Gujarat and Godavari (Odalarevu) in Andhra Pradesh. Square mesh window of 1 m x 0.75 m size made of 50 mm mesh size were fixed near the codend. Small mesh cover was fixed on top of the windows to retain the excluded fish (Fig. 8) for the study. Similarly bigeye BRD was also tried in all these centers.

Fig. 8. Square mesh window with cover and Bigeye BRD (right)

Juveniles of 41 species could escape through the BRD in Hooghly. The mean escapement of all the species from the BRD was found to be 0.65 kg and juveniles of hilsa formed 11.60% of the total catch excluded (Prajith et. al. 2017). The length of the excluded hilsa ranged from 37 to 55 mm. It was also found that percentage of juveniles of hilsa was more in surface set bag net compared to bottom set bag net in Hooghly. Juveniles of hilsa were negligible in the bag net catches of Fraserganj. Among the three sampling stations, species diversity was maximum in Fraserganj followed by Godakhali and only 4-5 species were encountered at Tribeni, which is more less a freshwater zone.

The bag net fitted with a 50 mm square mesh window showed an average escapement of

about 6.2 % of the total catch in Godavari. The catches at Odalarevu was dominated by small prawns (45.7%) followed by ponyfishes (18.0%), hilsa spp. (11.0%), ribbon fishes (9.0%), flat fishes (8.0%) and squilla (8.0%). The fishes excluded were anchovies, (35.1%), ponyfishes (32.4%), prawns (16.2%) and crabs (16.2%).

The results of the study conducted in Bhadbhut, Narmada had shown that 8-40% of juveniles of economically important fishes escaped through the BRD of which 7-15% were hilsa juveniles.

For optimizing the mesh sizes and position of the BRD to improve the escapement of juveniles, especially hilsa, further trials during breeding seasons are required. The highest abundance of juveniles of T. ilisha was observed at Tribeni centre. BRDs fabricated at different location for the trials are given Fig. 9.

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Bhadbhut, Gujarat Godakhali, West Bengal

Godavari, Andhra Pradesh

Fig. 9. BRD fabrication in selected centers in Hooghly, Godavari and Narmada estuaries

Based on the above study inputs were given for the preparation road map for the fisheries development in West Bengal. Three training programmes on hilsa conservation were also conducted in different places in West Bengal. Brochures and popular articles on hilsa conservation have been printed and circulated among the stakeholders.

Plastic litter in bag nets

It was found that along with fish catch, the strong currents bring large quantity of debris which clogs mesh openings of the net. Weight of debris per net per haul ranges 0.5kg in which plastics contributed major share (Fig.10). Large plastic bags and sheets entered in the net act as a screen, which almost fully prevents the filtration of the gears. Pradhan, et al (2017) reported that on an average, 10.3% of the catch of dol net is constituted by plastics.

Fig.10. Plastic debris in bag net catch in Hooghly

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Jellyfish problems in bag nets

Migration of jellyfish into the backwaters is a problem as it interfere the fishing operations. Clogging of jellyfish in set bag nets hamper the operations and destroy the gear. Pradhan, et al (2017) reported that jellyfish discards in the estuarine bag nets of Maharashtra. Jellyfish migrate as huge shoal and completely choke all kinds of fishing net. Due to excess load the net and the poles get damaged causing economic loss.

Conclusion

Several species of fishes have disappeared in the fishery from the marine and inland waters of our country and some more are in the verge of depletion due to changes in the ecosystem and anthropogenic activities. There is no proper licensing, registration or fishing effort control in our waters. Further, most of the fishing gears are non-selective and mechanism to control is inadequate. Since livelihood issues are rampant in the inland sector total ban of the bag net is not possible. Any kind of BRDs or operational related control on the fishing systems are generally unacceptable to the community. Unless alternative employment or source of income is made available, phasing out of these kinds of gears are not practical.

Occurrence of juveniles and sub-adults of hilsa in the bag net catches are very common. As we are experiencing the signs of over fishing, fishermen should adopt self-regulation in the hilsa migrating grounds rather than enforcement of regulations from the government. In an open access fishery scenario, where the fishermen have all rights to catch the fish, they also have the responsibility to sustain the fishery (FAO, 1995). Since management of hilsa fishery is the subject of the state, Government of West Bengal should try incentive based schemes as seen in Bangladesh for sustainable fishery. Total ban of single use plastic materials will reduce the litter load in the water bodies.

Fishery regulation and recommendations

1. Licensing and registration for stationary bag nets (craft and gears) need to be enforced.

2. Bag net operation in nursery grounds can be avoided.

3. Replace stationary bag nets with more selective fishing gears.

4. Phase-out bag nets from the estuaries to conserve juveniles and improve the fishery

5. Buyback schemes for fishing units can be implemented.

6. Self-regulation and Co-management of bagnet fishery.

7. Seasonal ban of bag nets may be observed, wherever required, for fishery improvement.

8. Incentives for responsible fishing practices and punishment for violation

References/suggested editing Amrutha R Krishnan, Talwar, N.A and Suman Das (2017) Experiment with T45 mesh windows in the throat

and in upper-lower belly of coastal set bagnet. Book of Abstracts 11th IFAF, Fostering Innovations in Fisheries and Aquaculture. 95 p

Boopendranath, M.R and Shahul Hameed, M. (2010) Energy Analysis of the Stake Net Operations, in Vembanad Lake, Kerala, India. Fish. Technol. Vol. 47(1): 35 - 40

FAO (1995) Cod of condact for responsible fisheries

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Jisha, H., SALY N. THOMAS, THOMSON, K.T. 2017. Bycatch and discards in stake nets off Kumbalam, Cochin backwaters, India. Book of Abstracts. 11th IFAF Fostering Innovations in Fisheries and Aquaculture. 107 p

Manojkumar, B, Rakesh, C.G and Devika Pillai (2017). Development of jellyfish excluder device for stake nets. Book of Abstracts 11th IFAF, Fostering Innovations in Fisheries and Aquaculture. 97 p

Kathavarayan et al (2002). Effect of square mesh panels on the catches of stationary bagnet in Hooghly Estuary. Fishery Technology. 39(1): 6-10

Pauly, K. V. (1991) Studies on the Commercially Important Fishing Gears of Vembanad Lake, Ph.D. Thesis, 171p, Cochin University of Science and Technology, Cochin

Prajith, K. K., M. P. Remesan, V. R. Madhu and P. Pravin (2017) Square Mesh Window for Reducing Hilsa Juvenile Bycatch in Stationary Bag nets. Fishery Technol. 54(2):137-140

Pradhan, S.K, Iburahim, S. A., Kamat, S.S., Latha Shenoy (2017) Fishing systems of estuaries in Maharashtra. Book of Abstracts 11th IFAF, Fostering Innovations in Fisheries and Aquaculture.p119.

Remesan, M. P., P. Pravin and Meenakumari, B (2009). Non-selective Fishing Gears and Sustainability Issues in the Hooghly-Matlah Estuary in West Bengal, India. Asian Fisheries Science 22 (2009): 297-308

Uskelwar L. S., Nirmale, V. H., Bhosale, B. P., Metar1, S. Y. and Chogale, N. D. J. Indigenous knowledge used in stake net (wan) fishery practiced along the Ratnagiri coast of Maharashtra. J. Mar. Biol. Ass. India, 59 (2): 45-52

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Dol Net Fishery of India: Need for Resource Conservation S. Monalisha Devi



Introduction

Dol net is a fixed tapering bag net which resembles a trawl net which are set in tidal streams and the net is held in place by attaching it to anchors. Dol netting is a very popular traditional, passive technique of fishing practiced along the north-west coast of India, in the states of Gujarat and Maharashtra. Dolnets were operated at a maximum depth of 20-24m which were close to the shore prior to mechanisation, but after mechanization of the crafts fishermen now set their nets at depths of 40m. Traditionally the Dolnet fabrication was using cotton twine, which were heavy and cumbersome which are now replaced by HDPE, which made the gears light, durable and also helped in easy deployment by the fishers. Dol nets are classified on the basis of the method and depth of their operation. The simplicity of its design, construction, operation and low investment has made this gear very popular among small-scale fishermen. Dol nets are operated by traditional, motorised as well as mechanised boats. Dol net can be efficiently operated at any depth in the water column and the gear is operated almost throughout the year.

Species of fish, which drift with the current or do not swim fast enough to counter the current form the major targeted catch in dolnets (Akerman, 1986). Dol nets are operated in three regions in Gujarat viz., Umbergaon to Kavi along the southern Gujarat, Siyalbet to Diu along the Saurashtra coast and Takkara to Modhwa in the Gulf of Kutch region (Nair et al. 2007). Among these, Saurashtra is the important region and the main fish landing centers are Jaffarabad, Rajpara, Navabunder and Goghla. Out of these the first three are the most important with more than 600 dol netters under operation (Manojkumar and Dineshbabu 1999). The Bombay duck, Harpodon nehereus (Ham.) is the main constituent of the catch so much that the 'dol' net fishery had become synonymous with Bombay duck fishery. The success of operation depends on favourable currents. Tapering of the net from mouth to the cod end is achieved by gradually reducing the size and number of meshes. Dol net design, its operation and fishery: Dolnet is a fixed tapering bag net, resembling a trawl net, set in tidal streams by attaching it to anchors for holding the net in place and floats are used to maintain the mouth opening of the gear. In the Maharashtra region the anchoring is done on the poles fixed to the sea bottom whereas in the Saurashtra coast heaps of stones are used as anchors. The success of operation depends on , currents and the period of operation is linked to the tidal pattern in the region where the gear is operated. In Navabandar, dol net was operated from the eleventh day of Gujarati month Akadashi to the fifth day of Gujarati month, Panchmi. During this period, water level and water current are favourable for dol net operation. After panchmi, fishermen wait for the next Akadashi for the tide and currents to be favourable.

The method of operation of Dolnets, differ significantly in Gujarat and Maharashtra mostly by the method of anchoring. Smaller bag nets are operated along other parts of the Indian coast, but mainly in estuaries and creeks. The dominant species caught in Dolnets along the north-west coast include Bombay duck, clupeids, elasmobranchs, catfishes, croakers, eels,

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ribbonfishes, threadfins, pomfrets, flat fishes, penaeid shrimps, non-penaeid shrimps and lobsters (Sehara and Karbhari, 1987).

Dolnet is divided into seven parts at Versova area they are name as Mohor which is mouth opening portion followed by Chirat, Katra , Mazvala, Khola, Par and Ambadpar the last portion (Fig. 1, Table 1). The detail information on overall length of the boat, engine power of the boat, depth of operation, number of nets use at one time, number of crews required in one time fishing is provided in Table 2 (Raje and Deshmukh, 1989). The main season of operation is divided into two; the first season from September to the middle of January and the second from February to May. Doln ets used along Navabander is divided into Bochi the mouth portion followed by Aor, Trijo, Bangu, Chothi, Jalo (the last portion of the The detail information on dol net in Navabander is given in Table 3 and Table 4

Fig. 1 Dol net in set position

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Table 1. Details of various sections of Dol Net at Versova (Raje and Deshmukh, 1989) Part of the net Mohor Chirat Katra Mazvala Khola Par Ambadpar

Average length (m) 11 13 13 16.5 5.5 5.5 5.5

Mesh-size from beginning to the end of that part (mm)

350-280

260-130 130-140

40-12 12 30-40 25-30

No. of meshes 1065-890

890-870 870-850

850-400 400 200 250

No. of creases between meshes

- 2 3 8 - - -

Polythylene twine size (mm)

1.5 1.0 1.0 1.0 1.0 1.25 1.0

Table 2. Details of size of boat, depth of operation, number of nets and crew strength (Raje and Deshmukh, 1989)

Overall length of boat (m)

Engine power (HP)

Depth of net operation (m)

No. of nets used

No of crew required

6.5-8 5-25 10-20 2 3-4

10-13 30-35 10-32 2-3 5-6

13-17 50-100 30-40 3 7

Table 3. Gear specifications for Dol nets operated at Navabandar (Sikotaria et.al 2018) Specification Measurements

Overall length (m) 60-90

Height (m) 14-15

Breadth (m) 28-36

Types of material HDPE, PP, PA

Parts of net Length (m) Mesh size (mm)

Bochi 14.0-18.0 110-130

Patiya 12.0-14.0 100-110

Aor 16.7-22.0 70-90

Trijo 09.0-14.0 45-70

Bangu 03.0-05.6 30-45

Chothi 02.4-04.6 15-20

Jalo 03.0-05.5 10-15

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Table 4. Vessel and engine specifications of crafts used by dol netters at Navabandar (Sikotaria et. al 2018)

Specification Measurement

Overall length (m) 10-12.8

Breadth (m) 2.4-3.6

Height (m) 1-1.8

Tonnage (t) 15-20

Fish hold (Number and capacity in kg)

1 no. & 1200 kg- 2 nos.. & 2500 kg

Voyage time (days) 8

Crew member 8-10

Depth of operation (m) 40-60

Engine power (Hp) 87-105

Number of cylinders 6

Engine make Ashok Leyland

Plate 1 Dol net catch at Maharashtra

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Dol net fishing at Saurashtra coast (Gujarat) Dol nets are operated almost throughout the year, but the main season can be divided into

two such as the first season from September to the middle of January and the second from February to May. This division is based on the shifting of the fishing grounds at all the three landing centres viz., Navabunder, Jaffarabad and Goghla. During the first season the fishing ground is located in the southeast direction from all the three landing centres. Fishing is done from this ground till the middle of January and afterwards the ground shifts towards north of the existing ground. This shifting takes place in about 15 days and the next fishing starts in the beginning of February. Dolnet being the fixed bag net the success of operation depends on the favourable currents, so the shifting of the ground must be associated with a change in the current patterns of the area.

The fishing ground is identified and stones are laid as marker for different 'dol' nets. The

fishing season starts with the laying of stones. The stones are purchased from nearby quarries and taken to the fishing ground. First a stone is laid with the rope followed by a number of stones through the attachment in the main rope. Two such stone heaps are made for each dol net. A dol net needs 50 to 60 stones. The dol net operation in Saurashtra is confined to depths ranging from 15 to 35 m. The anchor ropes are strongly based at the bottom with the help of these heaps. The other end of the rope is tied to the floats. Earlier floats were made of wooden barrels but now plastic cans and readymade floats are used for this purpose. The dol nets are attached to these ropes. The mouth of the net is placed against the tidal current and before the current changes the net is hauled and after emptying the catch it is again put in the opposite direction. The number of hauls depends upon the season and number of nets carried in a boat. The four net units generally do single hauls only whereas two and three netters do two hauls. The net is made up of HDPE with a codend mesh of 20 mm. The codend is double walled for extra protection. The length of the net varies from 40 to 80 m and costs around Rs.70,000 to 1,00,000. The ropes and net last for almost 10 years (check. The length of the craft used for the dolnet operation varies from 10 to 15 m with tonnage ranging from 5 to 20. Earlier the boats were with sails and were using wind power for propulsion. At present all the dol net units are motorised with engine power varying from 20 to 88 HP. They also carry sails along with them to utilise the favourable wind (Sikotaria et.al 2018).

Dol net fishing at Versova (Maharashtra )

Versova fishermen make use of iron poles which are dug deep in sea bed where it is

anchored using ropes. Different codend with mesh size varying from 10 to 40mm mesh size called par, is used when large sized fish, including Bombay Duck are available. Codend with 10-12mm mesh called Khola, is used for small-sized non-penaeid prawns, Acetes spp. A par with 25-30 mm mesh called ambad par, is generally used from March to June when Nematopalaemon tenuipes is abundant. The selective use of ambad par enables filtering off of smaller Acetes spp. also abundant in the same period, which otherwise block the cod end causing eddies. Another reason why fishermen do not prefer a mixture of Acetes and N. tenuipes is that their mixture fetches lower price than N. tenuipes alone.

Thus for Bombay duck, penaeid prawns, ghol, Coilia, N.tenuipes etc. generally a par is attached to mazvala and the net is set at bottom; whereas for pomfrets, scerfish, chirocentrus and other pelagic clupeids the net is set at surface by adjusting the length of so. A cod end with 10 mm mesh khola is used only when no quality fish, including Bombay duck is available and to catch

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Acetes sp.. This indicates that the fishermen use the different cod ends with varying mesh sizes to regulate their catch (Raje and Deshmukh, 1989). Need for resource conservation in dolnet fishing Dolnet fishing is operated in different depths of water. The dol net fishing though its success depends on water current large quantity of different varieties of fishes are caught in the net. Dolnets, though target Bombay duck, they also land different varieties of fishes including large quantity of juvenile of commercially important species. The very small mesh sizes used in the codend is one of the reason for the high juvenile capture rate, the govt. has stipulated 40 mm square mesh codend as legel, but the adherence to the provisions in the MFRA is minimal. The increase in the fishing power, as a resuls of the larger nets and bigger vessels adds to the problem of over exploitation. At present there is report of accidental catch of sea turtle and huge quantity of juvenile fishes. In the state of Maharashtra juvenile catch of Pomfret is becoming very common and its in alarming situation. Some of the places where huge number of juvenile catch are landed are Versova, Naigaon, Raongaon, Satpati, Dahanu (Plate 1). References / suggested reading Akerman, S. E. 1986. The coastal set bag net fishery of Bangladesh - trials and

investigations. Bay of Bengal Programme, BOBP/REP/34(FAO),GCP/RAS/040/AWS.

Anon. 2012. Gujarat fisheries statistics 2010-2011. Commissioner of Fisheries, Govt. of

Gujarat, Gandhinagar.

CMFRI 2010. Marine fisheries census 2010 Gujarat. Central Marine Fisheries Research

Institute, Kochi, p. 19-22.

Manojkumar, B. and Dineshbabu, A. P. 1999. Dol net fisheries of the Saurashtra coast. Bull.

Cent. Mar. Fish. Res. Inst., 161: 1-8.

Nair, K. V. S., Chakraborty, R. D., Savaria, Y. D., Polara, J. P., Dhokia, H. K. and Thumber,

B. P. 2007. Catfish fishery by dolnetters along the Saurashtra coast. Mar. Fish. Infor. Serv. T&E Ser., 193:

Raje, S.G. and Deshmukh Vinay D. 1989. On the dol net operation at Versova, Bombay.

Indian J. Fish., 36 (3): 239 - 248

Sehara, D. B. S. and Karbhari, J. P. 1987. A study on ‘Dol’ net fishery at selected centers in

north-west coast with special reference to costs and retunes. Bull. Cent. Mar. Fish. Res. Inst., 78: 1-15.

Sikotaria K.M., Temkar, G.S., Abdul Azeez, P. and Mathew, K.L. 2018. A case study on dol

net fishing operation and its economic analysis off Gujarat, north-west coast of India

Indian J. Fish., 65(4): 147-153

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Design, construction and operation of fishing pots and traps K. K. Prajith* and M. P. Remesan1

*Veraval Research Centre of Central Institute of Fisheries Technology, Veraval 1ICAR-Central Institute of Fisheries Technology, Kochi


Introduction

Trap fishing is one of the age-old fishing methods and it has been widely practised throughout the world in both tropical and temperate seas (Hawkins, et al., 2007). Pots and traps are gears which make the entry of the aquatic species easy and make the escapement difficult due to special designs. The parts of traps which prevent the escapement may be chambers, flaps, narrow paths, funnels etc. Enormous designs of pots and traps exist throughout the world. Based on the abiotic and biotic factors, pots and traps differ regionally in size, design, operation etc. According to FAO, traps are large structures fixed to the shore. Pots are smaller, movable traps, enclosed baskets or boxes which are deployed from any craft. In India, the usage “Pot” is not much common and the fish trapping devices are generally termed as “Traps”. Traps are generally operated in the area where other types of fishing gears cannot be operated due to uneven bottom or submerged obstacles. The advantages of trap fishing includes the following

• Trap fishing is economic and low energy is required when compared to active fishing

method. They are highly fuel efficient both in terms of f returns and biomass per unit of

fuel consumed (Wilimovsky and Alverson, 1971, Mohan Rajan, 1993).

• Organisms caught in the trap can be retrieved alive in an undamaged condition

• Traps can fish continuously day and night and required only periodical tending (Pravin et

al., 2011)

• They can be left in the sea during unfavorable weather conditions and can be collected

when favorable conditions set-in.

• Capital investment is relatively low and many traps show a high degree of selectivity.

Mechanism & Type of fish trapping

In India, based on the area of operation, pots and traps are classified mainly into pots and

traps of marine and inland sector. The inland traps and pots are very common and popular throughout the country. Even though various marine fish traps are operated for livelihood subsistence, organized marine trap fishing exists only in the Southern coast of the country especially in Tamil Nadu. Depends on the level of modernisation, traps are also classified into traditional traps and modern traps. Plunge baskets, box traps, filter traps, aproned filter traps screen barrier, bamboo screen barrier, net barrier, Chemballi koodu, chevu, Kalava traps, lobster traps, crab traps etc are some of the example for the traditional trapping systems ( Remesan, 2006, Remesan and Ramachandran, 2008). Details of some of the important traditional traps (Marine sector) are described below.

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Marine Fish traps The traditional fish traps operated along Gulf of Mannar, Palk bay and south coast are

known as koodu. These traps are mainly used for catching perches and perch like fishes. Fishers from Rameswaram evolved extremely elaborate stellate form of this traps with a roomy side chamber in each of the arm and even with 5 entrance of the interior. These traps are made of splinters of babul tree or with thin bamboo reepers or palmyrah leaf stalk fibers (Meenakumari, 2009). The meshes are hexagonal in shape with each side of the mesh having a length of 3-4cm. The length of the trap varies from 60-150cm, breadth from 60 to 120cm and height from 15 to 45 cm.

Kalava traps

Kalava traps are operated for kalava and perches. They are used in rocky sea bottom and submerged reefs in depth ranging 60-150m along the west and east coast of India. Traditional Kalava traps are known as Rameswaram type traps. Modified modern kalava traps are also operational in the various part of the country. These rectangular traps made of 10mm dia MS rods with strengthening ribs. These rods are joined together with coil hinges so as to facilitate collapse of the trap when not in use. Lobster traps

Spiny lobsters are traditionally caught from the south coast of India with traditional

lobster traps. These traditional traps are called as Colachal traps. They are heart shaped/ arrow headed trap locally fabricated with biodegradable materials. By understanding the shortcomings and operational difficulties of the traditional traps, ICAR-CIFT has developed and popularized modern lobster trap for this region (Meenakumari et al., 2009). These traps were accepted by fishermen (Fig.1) due to special deign and durability.

Gargoor fish traps, Caribbean traps (arrowhead, "Z", "S", etc.); round traps, rectangular traps;"D"-shaped traps, collapsible traps, pelagic fish traps, North Atlantic cod pots, plastic multipurpose traps are some of the common designs used throughout the world.

In trap fishing, fishes are caught by attracting (using bait or any other attractant) or

forcefully directing to specially designed traps or trapping area by utilising the behaviour of the targeted species. The diversity of fish traps designs ranges from natural structures like rocks and corals to specially designed species specific traps (Slack-Smit, 2001). . Based on the nature of catching mechanism, material of constriction and design, tarps are classified in to various categories.

Table 1: Details of various types of fish traps and trapping mechanisms

SL No Trapping

mechanism/ trap type

Details

1 Barrier type

As the name indicates these traps acts as an obstacle for fish movement. Physical constructions like dams, fences, nets etc act as barrier that may or may not be closed by the fisher after the entry of fishes.

2 Habitat traps In habitat traps, the fishes which have the hiding

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behaviour are mainly targeted. The brush traps and octopus pots are example for this

3 Tubular traps

Tubular traps are slender funnel shaped traps with a bell shaped mouth and a narrow neck in the hinder region. The narrow funnel stops the fishes from getting out backwards. Eel tubes are good example for a tubular trap.

4 Mechanically operated traps

Gravity traps (box traps) and Bent-rod traps that are examples for mechanically operated traps. The traps are mechanically closed by the fishers

5 Basket traps

Most of the advanced trap designs are the modification of basket traps. These traps have special designs which make easy entry but the escapement or backward movement difficult or impossible. These types of traps are fabricated with wood, bamboo, plant leaves, plastics, metals, synthetic yarn etc.

6 Large open traps

Large panel of nets or mended bamboo panels or similar constructions are used in large open traps. Usually there will be a mechanism to stop fish from escaping, which can be fixed on sticks or anchors, set or floating.

7 Aerial traps

Aerial traps are normally set out of the water. Some fishes when in danger, excited or under physical pressure jump out of water. Any suitable horizontal nets, rafts or boats or boxes can be used to collect the fishes as they fall back. Pitfall traps used for catching crabs during their migration to shore come under aerial traps. Fishes like mullet and milkfish are harvested using this type of mechanism in south Indian states like Kerala, Tamilnadu and Andhra Pradesh.

Targeted species

Most of the fishes, crustaceans and cephalopods can be caught with traps and pots. The catch rate of the trap fishing depends on the distribution and assemblage of the targeted species in the fishing ground also the behaviour of the fishes.

The species of fish, crustaceans and cephalopods caught in the different regions of the world

are often characteristic of those regions. Some types, however, are found in a wide range of marine and estuarine areas, for example snappers, sharks and squids (Slack-Smit, 2001).

In India,, shallow-water reef and estuarine fish and shellfish are commonly caught with traps

and pots, Most pots and traps used in the tropics have been designed for fishing in reefs, rocky areas and on the rough bottom. The fish, cephalopods and crustaceans taken include snappers, emperors, groupers, parrot fish, surgeon fish, squirrelfish, angelfish, tropical rock lobsters and others. Pot fishery is widespread in mangrove creeks and estuarine areas for various crabs (mud crabs, swimmer crabs, spanner crabs, etc.), adult prawns (giant freshwater prawn) and a number of offshore shrimps. Various types of squid and octopus are also trapped in most tropical waters.

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Factors considered during the fabrication of fish traps

The cost for material and the charge for fabrication of fishing traps should be made minimal, by using locally and easily available materials. The martial used for the construction should be durable and should be able to withstand the physical stress of the fishing environment. If the traps are for marine use, the material used should be sturdy in sea water or it should be coated or treated with suitable anti corrosion agent. By using biodegradable

materials, ghost fishing can be prevented in the event of losing the trap during operation. The design should be simple and easy to set and haul. The gear should be easy to carry in the vessel and should not have any complex structures, projections or attachments. The catch quantity can be improved by using more number of traps. For this stack ability of the gear plays an important role. If the traps are of light weight and collapsible, more number of gear can be accommodated in boat or vessel. The design should be selected based on the biological characteristics of the targeted species like morphology, feeding and swimming behavior, niche etc. Any designs mentioned in table 1 can be selected depending on the physical and biological characteristics of the fishing ground and targeted species respectively.

Parts of a typical fishing trap

A typical fish trap consists of the following parts

Main frame skeleton (rib)

Frames are the main skeleton or ribs of trap. Usually strong materials prevent the traps and pots from losing their shape during fishing. Wood, bamboo or metal are the commonly used materials for the fabrication of main ribs, The outer covering

This part may be with bamboo slits, synthetic meshes or metallic webbings. In traditional

pots, coconut or palms leaves are used. The selection of material is mainly based on the traditional usage, cost and availability. Funnel (entrance)

Funnel or entrance is the major part of a trap. These are the entrance to the trap. The number of funnel varies depending on the design of the trap. The entrance may be single or multiple. Studies show that more number of funnel increases the catching efficacy of the gear. Door

Doors are referred to the catch collecting area. Some designs may be provided with, an area where the meshes can be opened and closed for collecting the catch Escape gaps

An Escape vent ensures responsible fishing. These are the gates for the escapement of

juveniles entering inside the gear (Fig 1). Escape gaps are common in lobster traps in many parts of the world, but not in India.

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Bait area

Normally bait will be provided in the trap to attract the fishes. Bait will be fixed in the main chamber of the trap with suitable bait bags or chambers. Small pelagic fishes, slaughter house waste and small animals are commonly used as bait for attracting the fishes. Even artificially formulated bait can be used in traps. Ballast

In the area with higher tidal flow or current, suitable weights need to be provided in the

traps to prevent losing of traps. Ballast are normally used in the traps constructed with light weight material. Ballast also helps to maintain the original posture of the traps during operation.

Fig. 1. Modern lobster trap (ICAR-CIFT Design)

Collapsible fish traps – Design and construction

Use of collapsible traps is an option to increase the catch rate and profitability of fishers. By using foldable traps, more number of traps can be stacked in the fishing craft. Recently ICAR-CIFT has developed a collapsible fish trap for marine and inland waters. These collapsible traps are of simple design and fishers can easily adopt the technology. These traps are of low cost and light weight when compared to the conventional traps.

The trap is made with two rectangular stainless steel frames of 1.0 X 0.60 m size and two

square frames of 0.6 X 0.6 m size (Fig. 2). The two sides of the frames are cover with high density polyethylene netting with 80 mm mesh size and 1.25 mm diameter. The entrance funnel of the trap is made of polymer mesh netting. A 4 mm diameter PP rope is attached at the centre of the upper frame with a float attached at the other end for locating and retrieving the trap (Remesan and Prajith, 2018).

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Fig. 2. ICAR-CIFT collapsible fish trap spherical and oval mouth designs Operation of traps

Before operating traps, we should have some basic idea on following things (Slack-Smit,

2001). ●The type(s) of fish you want to catch and the type(s) of traps or pots that will catch them;

● The type(s) of bait needed for these fish and where you can get it;

● Suitable landing and storage for your catch on board;

● Market for your catch Simple trapping and potting can be carried out from small boats or canoes or from large

vessels. The efficiency of fishing with pots or traps can be improved by the use of equipment like power winches, haulers etc. Once the fishing grounds are fixed, traps can be setup at any time of a day.

Buoys or floats are normally attached to mark the location of the traps. There will be a buoy line attached to the traps/pots for the operation. Proper rigging is essential for the successful operation of the gear. The type and size of the buoy and the length of the buoy line vary based on the area of operation. Normally the length of float line is kept as one and half to twice the water depth of the fishing ground. The length of the line can be increased if the water current is higher at the fishing site. Bright coloured flags, radar, reflectors and even radio beacons are used in advanced trap designs for easy identification. Traps can be operated as single or in series (Slack-Smit, 2001).

Traps and pots can be operated with or without bait. In the case of habitat traps, there will not be provision for the bait attaching area. Funnel shape and positioning of the bait play

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important role in catch rate. Normally, centre of the traps is the ideal location for attaching the bait. The position of the bait can be optimised by fishers by continuous trial and error method. Depending upon the targeted species, waste from poultry slaughter house, fish and shrimp waste, molluscan meat, wheat flour mix etc can be used as bait. Quality of a good bait include effectiveness to attract targeted species, easy to attach in the gear, long lasting, local availability, low cost etc.

Soaking time also depends on the targeted species and its behaviour. It also depends on

the species abundance at the fishing ground. Soaking time varies from few minutes to two to three days while 12- 24 hours is ideal soaking time.

After suitable soaking time, traps can be hauled onboard. This can be done either by

hand or by mechanical hauler. After collecting the catch, re-baiting can be done and traps can be deployed again in the same or different location. Ghost fishing in trap sector

Due to bad weather condition, gear conflicts, physical condition of the fishing ground, entangling of large marine animals etc. there will be a chance to loose or abandon the fishing gear during operation. These lost or discarded fishing gear which are no longer under a fisherman’s control known as derelict fishing gear (DFG), can continue to trap and kill fish, crustaceans, marine mammals, sea turtles, and seabirds. The most common types of DFG to ghost fish are gillnets and pots/traps. Ghost fishing can impose a variety of harmful impacts, including: the ability to kill target and non-target organisms, including endangered and protected species; causing damage to underwater habitats such as coral reefs and benthic fauna; and contributing to marine pollution (NOAA, 2015). To prevent the ghost fishing in traps fisheries, the following steps can be adopted.

• Using proper ballast and anchoring mechanism

• Always operate traps in good weather condition

• During unfavourable conditions, remove traps from fishing ground

• Select suitable site for the installation of traps

• Always provide escape vent or escaping mechanism in the design.

• Use of biodegradable meshes in specific locations

Conclusion

Traps are highly energy efficient low cost fishing gears with high size selectivity. Trapping allows some control over the species and sizes of the catch. The trap entrance, or funnel, can be regulated to control the size of fish that enter. Fresh and live catch ensure premium price to the fishers. Once the traps are set, the fishers can operate other gear or engage in other works to increase their income. Collapsible traps developed by ICAR-CIFT permit the transportation and operation of several traps at a time unlike traditional rigid traps (Remesan et al., 2006). In the context of energy conservation and responsible fishing techniques, trap fishing in the artisanal sector need to be promoted.

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References/suggested reading Cochrane, Kevern, L. (2002) A Fishery Manager's Guidebook - Management Measures and Their

Application, FAO fisheries technical paper. 424 p

Hawkins, Ulie, P., Callum M., Roberts, Fiona, R. Gell and Calvin Dytham (2007) Effects of trap fishing on reef fish communities, Aquatic Conser Mar. Freshw. Ecosyst. 17: 111–132

Meenakumari, B., Boopendranath, M.R., Pravin, P., Thomas, S. N and Edwin, L. (2009) Eds) Handbook of Fishing Technology, Central Institute of Fisheries Technology, Cochin:vii+372 p

Mohanrajan, M. (1993) Fish trapping devices and methods of southern India, Fish. Technol. 36: 85-92

NOAA (2015) Marine Debris Program. 2015 Report on the impacts of “ghost fishing” via derelict fishing gear. Silver Spring, MD. 25 p

Pravin P., Meenakumari, B., Baiju, M., Barman, J., Baruah, D. and Kakati, B (2011) Fish trapping devices and methods in Assam - A review. Indian J. Fish. 58(2): 127-135

Remesan M.P (2006) Studies on inland fishing gears of north Kerala. PhD Thesis, Cochin University of Science and Technology.

Remesan M.P and Prajith K.K., 2018. CIFT Meen koodukal (CIFT fish traps) in malayalam, ICAR –CIFT training manual

Remesan M.P and Ramachandran A, (2008) Fish traps in the nland waters of North Kerala. Fishery Technology. 45(2): 137-146

Slack- Smith, R. J. (2001) Fishing with traps and pots, FAO Training series 26

Von Brandt, A. (1959) Classification of fishing gear, p. 274-296. In: Modern fishing gear of the world (Kristjonsson, H., Ed.) London, Fishing News Books Ltd.

Wilimovsky, N .J. and Alverson, D. L. (1971) In: Modern Fishing Gear of the World (Kristjonsson, H., Ed.) Vol. 3, Fishing News (Books) Ltd. London. 509 p

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Onboard Handling and Processing of Tuna

K. Ashok Kumar Fishing Technology Division, ICAR-Central Institute of Fisheries Technology, Kochi


Introduction

The world demand for tuna is large and growing. Tuna processing industry has grown very rapidly in the last decade. In addition to the conventional processed products such as smoked, canned and frozen products, there is an increasing demand for the prime quality fresh tuna meat for sashimi and sushi production, which commands higher prices especially in the Japanese market. A review of the world tuna market revealed the existence of three categories.

1. The high-priced sashimi grade tuna catering to the soaring Japanese demand 2. The canned tuna, especially the low-priced skipjack segment, is relatively oversupplied

and facing depressed demand and declining prices. 3. The third sector involving trade in fresh and frozen tuna.

Tuna is an important trade item, with about 40% of the catch entering global trade. For development of tuna fisheries, India must evolve medium to long-term strategies to participate in all the three areas of the world tuna market. The production of sashimi grade tuna in India requires special mention as it is only in its developmental stage and requires a real boost to catch up in the Japanese market. For Sashimi grade products, killing, damaging the brain, bleeding, gutting, precooling, freezing to -60°C etc are to be followed. Proper handling starting from catching and implementation of good handling procedures based on HACCP concepts, at every stage are highly required. The work done in India in tuna processing is related to various processing methods and product development. The work on production of sashimi grade tuna is comparatively limited. Not much work has been done on the utilization of oceanic tuna.

Tuna is unique among bony fish. It has high metabolic rate and higher body temperature than ambient temperature. It is reported that when tuna struggles, it uses all its energy to fight for escape. Hence it is very important to bring the tuna to the pre-exercise level before it is removed from the hook. The glycogen is depleted considerably during struggle. The Adenosine triphosphate, the chemical store of energy in the muscle starts decomposing. The struggled fish enters into rigor mortis very quickly after death. This has a deleterious effect on the quality of the meat. It is better to have a longer pre-rigor and rigor period for maintaining the quality. The struggling of tuna causes to accumulate lactic in the muscle in the live condition itself within a short period of struggle. This causes visual changes in the colour of the muscle and develops an effect known as ‘burnt fish’.

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Allowing minimum struggle during catch and onboard allows the quality of the muscle to retain for a longer period and also the shelf life. Bleeding of the fish reduces the post-mortem production of lactic acid. Other factors which contribute to the quality of meat are feeding habits, nature of food available, presence of parasites, sexual maturation, disease, fat content, killing methods, handling procedures, chilling and storage methods and holding temperature. The intervention to improve the quality can be done in the latter three parameters.

If tuna is not properly chilled immediately after capture, the high body temperature of tuna meat coupled with the presence of oxygen and iron in blood causes lipid oxidation and decomposition. This will lead to off taste of the meat due to rancidity. Proper bleeding can reduce a good source of oxygen and the pro-oxidant, iron.

Rapid chilling and maintaining at 0°C throughout handling is recommended to get high quality meat. If the quality of tuna is to be maintained for a long period, it has to be frozen to -60oC in a period of 8 h or less and should be stored at –50°C.

The storage life of chilled tuna is 10-12 days. Frozen tuna has the same initial quality as chilled tuna, but the thawed tuna has a short life of 3 days due to noticeable changes in colour and texture.

Handling of Catch Onboard

The various handling steps onboard fishing vessels are

1. Catch the fish with minimum stress, 2. The storage area of the vessel should be clean and safe 3. Quick stunning and killing of the fish 4. Destroying the spinal cord. 5. Proper removal of blood, guts and intestines without breaking 6. Washing in clean and safe water/ seawater 7. Lowering the temperature of the fish to 0°C by using chilled seawater and ice mixture 8. Storage the fish properly after chilling in flake ice or finely powdered ice in insulated

containers or fish hold.

Handling and storage of tuna for sashimi:

Tuna is killed either by a sharp blow to the head or inserting a spike into the brain at the soft spot. The soft spot is found between the two eyes. The purpose of giving a sharp blow is to prevent struggling, which will result in the development of anaerobic glycolysis and formation of lactic acid. The glycolysis will result in early ATP degradation and the resultant rigor mortis within a short period after death. This will affect the quality of the material.

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The brain should be destroyed by piercing a sharp object into the brain. The nerves should also be destroyed. The spinal cord can be destroyed by inserting a rod through the brain and into the spinal canal. This is carried out by cutting a wedge over the soft spot to expose the brain and then passing the rod through the brain into the spinal canal. The brain and spinal cord are destroyed to prevent enzyme actions and reduce the body temperature, which is controlled by the blood flow.

Tuna must be bled as soon as possible after the catch. Removal of the hot blood will allow the tuna to cool faster and reduce acidity. Blood is a source of iron, which is a pro oxidant. This will activate the peroxidation of fat and its decomposition, which will result in the development of off odours. There are three steps in bleeding.

1. Make a cut of 2 inches long behind the pectoral fin with a clean knife of 2 inches long and ½ inches wide so as to cut the blood vessel. The fish must be cut on both sides.

2. The next step is to cut the blood vessels in the gills. By opening the gill cover, make cut through the membrane behind the gill to cut the blood vessel without damaging the heart. This is repeated with the other gill also.

3. The final step is to cut vertically on both sides of the tail between the third and fourth dorsal fin without removing the tail.

During these cutting operations clean salt water must be running over the cut so as to prevent the blood from clotting.

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Gutting and Gilling

It is important that all the internal organs are removed as quickly as possible after bleeding. To remove the internal organs, make a straight cut 4 inches long in the belly cutting towards the anus. The anus should not be cut

through; but cut as close to the anus as possible may be made. The attachment of intestine to the body wall is removed by pulling it through the cut. Next step is to remove the gills from the head without damaging the heart. Cut the main muscle attaching the gill cover to the head and also the membrane behind the gills. Remove the gills and guts and any remaining attachments. On completion of this process, the belly area and gill portion must be properly cleaned using clean and safe seawater. The cut remnants and blood should be completely removed. The gill area is usually scrubbed with a soft nylon brush to remove complete blood in that area. After the process is completed, the outer surface must be washed properly to remove any slime or foreign material present. The seawater used for cleaning must be cooled. This will also help the initial cooling of tuna.

Gut contains a large amount of enzymes and hydrolytic bacteria. These enzymes will act on the belly walls, which will make the belly wall soft and penetration of bacteria easy. Since the gut contains digested food materials, it is a good source for the bacteria to grow. These bacteria will penetrate into the muscle through the soft belly wall caused by the enzyme action and make the flesh to deteriorate early.

Chilling

After the gutting, gilling, bleeding and cleaning operations are over, it must be kept in salt water ice slurry for a period of upto 12 hours or until the core temperature of tuna reaches 0°C. The mixture of ice and water should have at least two parts of ice to one part of water. This procedure

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should be adopted on vessels wherever possible. Better quality product is obtained if the temperature is lowered as quickly as possible. In small vessels where these operations are not possible, the tuna must be stored in ice immediately after catch. Sufficient ice should be added or repacked periodically to ensure proper cooling. Early chilling is advantageous to bring down the temperature to zero degree centigrade and the following problems will be reduced considerably.

1. reduce the burnt tuna syndrome (BTS). 2. reduce the enzyme activity 3. reduce bacterial growth

Icing Tuna Onboard

When the core temperature attains 0°C, the tuna must be removed from the ice slurry and kept in fish hold having one layer of ice in the bottom. The belly part of the tuna must be packed properly with ice. The outer area of the tuna must be covered with a green tuna paper soaked in salt water so as to protect the skin from damage during contact with ice. Fresh water causes bleaching of skin, whereas saltwater helps to maintain the natural colour of the skin. Green tuna paper is a special parchment paper available in Japan.

If block ice is used for icing, it must be properly crushed. There should not be any large pieces of ice or pieces with sharp edge. The tuna should be properly covered with ice throughout the storage. The tuna are placed head to tail to ensure sufficient ice between each fish. Tuna must be laid flat to ensure that tuna does not bend. Bending will cause tearing of meat. There can be two layers of tuna in a fish hold. If more layers are needed, shelving must be used. Between each layers of tuna, there should be at least 30 cm of ice. The ice should be spread evenly over the fish. The melt water must be able to run clear of the fish and melt water must be removed. Large and small tuna must not be iced together. Refrigerated seawater system also can be used. In this system tuna must be kept in plastic bags.

When tuna is stored in the fresh state, the temperature of the meat should not fall below –2.5°Csince rapid browning of the meat in the outer layer can occur at this temperature.

Onboard Freezing of Tuna

All the handling and processing operations must be carried out before freezing the fish. The core temperature of tuna must be reduced to –60°C within 8 hours. The shorter the time, the better is the quality. Air blast freezing is recommended. Tuna should be suspended vertically by the tail or aligned the head first in the air blast freezing. Tuna must be placed flat and protected from bending. The recommended storage temperature for sashimi type tuna is –50°C or below.

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Process Control

• Requirements 1. Proper washing during and after processing and ensure removal of blood, gut remnants

and foreign material 2. Use of clean and safe sea water 3. Handle and process tuna quickly and carefully after being taken onboard 4. Cool tuna in ice slurry with 2:1 ice water ratio 5. Keep only properly cooled tuna in fish hold 6. Keep tuna properly to avoid bending 7. Check the temperature of fish hold and tuna at regular intervals and ensure that the core

temperature is 0°C 8. In the case of freezing tuna the core temperature should be lowered to –60°C within 8

hours

Defects 1. Inadequate washing 2. Improper cooling

Fresh Storage Requirements

1. Fish hold must be free from any contamination 2. Fish hold must be properly insulated 3. The ice should be clean and safe 4. In RSW system, only clean and safe seawater with adequate temperature should be used 5. The core temperature of the tuna must be maintained at 0°C

Handling of Tuna On-shore

The material should be delivered at the receiving end in insulated containers in ice or in ice water slurry. Care should be taken to control the temperature rise and prevent the material from any damage during handling onshore.

At the receiving end, the tuna should be sorted and graded. All material, which are decomposed, unwholesome or contaminated shall be removed. Also remove all un-gutted tuna. Do not keep tuna on the floor of the receiving area to avoid contamination. Grading should be conducted based on colour, condition and size.

Freezing Methods

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There are two types of frozen tuna. The first category are tuna frozen at –20 to –30°C destined for canning, and the second category are tuna frozen at ultra-low temperature (ULT) of –50 to –70°C destined for raw consumption. Frozen tuna using ULT method can be stored up to two years without significant quality changes. However, thawed ULT frozen tuna usually has a shorter shelf life compared to chilled tuna. While chilled tuna has a shelf life up to twelve days at 0°C, thawed tuna has a commercial shelf life of only three days before the taste and colour changes become noticeable. Thawed tuna also tends to exudate drip accompanied by rapid textural changes.

To obtain sashimi quality frozen tuna, all the aforementioned handling methods have also to be followed. Tuna has to be immediately chilled and maintained at chill temperature prior to freezing. Immersion or air-blast freezing would serve the purpose, and tuna should be suspended vertically by the tail, or aligned headfirst into the air blast. The frozen product should then be stored at –50°C and maintained at this temperature until final sale to avoid desiccation and freezer burn. The best quality tuna has round sides and a straight natural appearance. Tuna stored in a bent position will suffer gaping or tissue damage upon thawing. Frozen tuna could meet the quality standards for sashimi when they are immediately frozen until the body temperature of –55°C is reached, and held there for at least 5 hours followed by frozen storage at –45 to –50°C.

Frozen storage requirements

1. Freeze tuna to –60°C within 8 hours 2. Frozen storage temperature should be at least –50°C or below 3. Record the temperature of frozen storage 4. During handling, transportation, and storage, the rise in product temperature should be

minimized Packing and Air Freighting International Air Traffic Authority (IATA) regulations call for stringent air freighting practice for fresh chilled tuna, particularly to avoid leakage and fishy odour. Various containers have been developed to serve the purpose, including sturdy plywood boxes or single sheet waxed fiberboard boxes. Both types are usually insulated with polystyrene sheeting (25-30 mm) and lined with polyethylene to ensure water – tightness. Prior to shipping, the tuna have to be chilled to a core temperature of less than 5°C and the temperature has to be maintained throughout the transportation process.

Tuna Grading

All imported chilled tuna to Japan are sold by auction. Initially, buyers inspect tuna prior to sale to evaluate the quality and to determine the bidding price. Tuna are usually graded according to freshness, meat colour, oil content (fatness), physical condition and size, although there is a slight variation in their order of importance from market to market. Because of environmental variations and fishing methods used, only a small proportion of tuna catch will fetch high prices, the bulk comprising medium and lower grade species. It should be borne in mind that tuna carcasses are further graded into high, medium and low-priced cuts. The cuts grade will determine the end-uses and their possible substitution. Toro meat of blue fin and big eye, for example, have no direct substitute, but lower grade akami might be substituted by other fish

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including skipjack, yellow tail or marlin. Grading systems based on colour and conditions scores are given below.

Condition Scores For Yellowfin and Bigeye Tuna 1.Very good (Score 50)

No apparent defects/damage (no rips, tears, cuts, abrasions) Scales intact Fish looks as though it has been lifted from the water; Natural body colour, bright Flesh at notch very firm (springs back quickly on pressing lightly with finger tips. No ‘soft

spots’ present on carcass surface 2.Good (Score 40)

Slight defects/damage (a few minor rips, tears, cuts, abrasions) Some scales lost Body colour are a little dull Flesh at notch firm, springs back slowly on pressing lightly with fingertips. One or two

very small ‘soft spots’ present on carcass surface

3. Medium (Score 30) Noticeable defects/damage (a maximum of two rips, tears, cuts, abrasions which

could affect meat yield) Small patches of scales lost Body colour dull/dark Evidence of minor water ingress (bleaching), and/or red staining Flash at notch less firm, does not spring back fully on pressing lightly with fingertips.

Several ‘small spots’ present on carcass surface

4. Poor (Score 20) More than two rips, tears, cuts or abrasions which could affect meat yield Large patches of scales lost Body colour dark Bleaching, red staining very apparent Flesh at notch soft, does not spring back at all on pressing lightly with fingertips.

Large soft areas on carcass surface

5. Very Poor (Score 10) Severe body damage, distortion Severe scales loss Body colour dark Severe bleaching, staining Flesh at notch very soft, falling apart, Carcass surface breaking up Meat has evidence of parasites or disease

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Colour Scores for Yellowfin 1. Very Good (Score 50)

Meat is translucent, glossy Colour are bright Fat is clearly visible in the out layer

2. Good (Score 40)

Meat is a little translucent, and less glossy Colour are less bright Fat just visible in outer layers

3. Medium (score 30)

Meat is translucent, and has lost its gloss Colours are a little brown No fat visible in outer layers

4. Poor (Score 20)

Meat is almost opaque. No gloss Colours distinctly brownish and dull No fat visible in outer layers

5. Very Poor (Score 10)

Meat is opaque Colour is brown, whitish, or gray No fat visible in outer layers

Colour Scores For Bigeye Tuna 1. Very Good (Score 50)

Meat is translucent, glossy Colour are bright Large amounts of fat, penetrating into the inner muscle layers

2. Good (Score 40)

Meat is a little translucent, and less glossy Colour are less bright Large amounts of fat, penetrating into the inner muscle layers

3. Medium (score 30)

Meat is translucent, and has lost its gloss Colours are a little dull Fat is present, but with little or no penetration into the inner muscles Meat colour may appear a little brown

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4. Poor (Score 20)

Meat is almost opaque. The colour of the meat is distinct brownish, and dull There is little or no visible fat in the outer muscle layers. Meat has the same colour

throughout

6. Very Poor (Score 10) Meat is opaque The colour of the meat is brown, white or gray Little or no fat visible in outer layers

Tuna intended for sashimi should be free from all patpathogenic organisms and should not have any harmful chemical compounds. Tuna contains high amount of the amino acid histidine, which is converted to histamine during microbial spoilage. It is a harmful chemical and the presence indicates the bacterial growth. The chemical and microbiological changes are also reflected in the colour and condition of the fish. The acceptability of tuna based on condition score and colour score are given in the following flow chart. Skillful handling and care is needed to maintain the quality

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Flowchart for Tuna Grading No No Yes Yes

Yes Yes

No Yes Yes

Value Addition

A wide range of tuna products is available in the international market. They include sashimi tuna, raw frozen tuna in the round and as cleaned tuna loins, fresh tuna in local markets, tuna burgers, tuna jerky, tuna sausage, tuna roe, and tuna in pouch products. Speciality products include smoked tuna, katsuobushi, tuna steaks, seasoned tuna cubes, barbecued tuna slice, tuna ham, and tuna fillets. Animal feed and pet food are also produced from the processing waste from tuna canneries.

Yellowfin Bigeye

Above 25 kg Direct to non-sashimi Above 30 kg

Condition score 30-50? Condition score 30-50?

Process on board as sashimi and chill in ice/seawater slurry then ice

Process on board as sashimi and chill in ice/seawater slurry then ice

Japan possibles

Is meat colour score 40-50 Is condition score 30-50

Is meat colour score 30-40 Is condition score 30-50

Pack chilled and export as high grade sashimi

Pack chilled and export as middle grade sashimi

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Canning

Indian canned tuna finds limited export market besides catering to the needs of defence personnel and internal market. Tuna is more susceptible to histamine development than sardines or mackerel. The method for canning tuna in different containers like tin can, tin free steel cans, aluminium cans and retort pouches have been standardized. High temperature short time process will yield a better quality product. Rotating retort cages during the thermal processing of tuna can reduce the process time and decrease energy consumption during processing.

Modified Atmosphere Packaging

Modified atmosphere packaging (MAP) gives only slight inhibition of histamine-forming bacteria in bigeye tuna. But storage in MAP with 40% CO2 and 60% O2 is reported better than Vacuum Packaging for cold storage of fresh tuna. No histamine formation is found in tuna stored under 40% CO2/60% O2 for 28 days at near 0°C.

Pulsed Light Treatment

Pulsed light treatment is an innovative technological concept that has great potential for extending the shelf life of foods, without a heat treatment step. It is a method of food preservation that involves the use of intense and short duration pulses of broad - spectrum white light where each pulse, or flash, of light lasts a fraction of a second and the intensity of each flash is approximately 20,000times the intensity of sunlight at sea level. It reduces the microbial load considerably of such products. This can be utilized for the extension of shelf life of chilled tuna and disinfestation of masmin.

Utilization of Tuna Waste

Several products can be prepared from the waste obtained during canning of tuna like wafers, paste, fingers and cutlets. The tuna processing waste can also be utilized for the preparation of silage.

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Quality and Safety Requirements for Fishing Harbours and Landing Centers

Ancy Sebastian ICAR-Central Institute of Fisherries Technology, Kochi


Introduction

A fishing harbour is a stretch of water body providing safe anchorage of fishing vessels, executing activities like landing, handling, processing and marketing of fish, facilitating meeting of buyers, sellers and service providers thus making it a point of convergence between production and trade. Fishing harbour development in India

Until 1950, there were about 1,300 fish landing centres scattered along the Indian coastline. Most centers were open beaches, where basic facilities for landing and disposal of the catch were not available. It was during the second Five-Year Plan, that the assistance of the FAO was availed of in identifying suitable landing sites and deciding on the nature of facilities to be provided. The increase in number of mechanized fishing boats and the establishment of freezing and exporting units necessitated the need for better landing facilities. By 1975 the construction of fishing harbours at major and minor ports and provision of landing facilities at various sites were taken up. The initial approach was to provide limited landing and berthing facilities such as a jetty, deepening of the entrance channel, provision of a breakwater, market hall, guide lights, etc. Such facilities were provided at about 90 sites, the most important of which are Porbander, Mangrol, Veraval, Navabunder and Jaffrabad in Gujarat, Karwar in Karnataka, Ponnani, Baliapatnam, Mopla Bay, Beypore, Azhicode and Vizhinjam in Kerala, Rameswaram, Nagapatnam, Cuddalore and Tuticorin in Tamil Nadu, Kakinada in Andhra Pradesh and Chandipur in Orissa.

Pre-Investment Survey of Fishing Harbours (PISFH) was established in 1968, with UNDP special fund assistance initially for a period of five years, the subsequent two years by SIDA and thereafter it has been a national project fully funded by the Government of India. With the establishment of the PISFH project at Bangalore, detailed surveys were undertaken and designs were prepared for the construction of large, self-contained fishing harbours, usually with components such as breakwater, navigation lights, dredged channel and basin, jetties, wharves, auction halls, slipways, boat and net repair sheds, public utilities, electricity, water supply, sewerage, drainage, approach roads and back-up space for fish-based industries, such as ice plants, processing plants, cold storages, etc. On the basis of pre investment surveys and evaluation, investment decisions were made and the work of construction entrusted to the various state governments. The Govt. of India has been providing financial assistance ranging from 50–100% of total costs to implementing agencies. Responsibility for the construction, management and maintenance of the facilities is however held by the respective State Governments, Union Territories and Port Trusts. The National Fisheries Development Board also extends 100 percent financial assistance for modification, repair and renovation. An attempt to upgrade fishing harbours to international standards was also made by FAO, through the

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Technical Cooperation Project (TCP/IND/3102 A) in two fishing harbours, Dhamara fishing harbour in Orissa and Mangrol fishing harbour in Gujarat from 2007 to 2009 (BOBP 2011). Today, India has 9 major fishing harbours, 48 minor fishing harbours and 780 landing centers besides a lot of small unrecognized landing centers.

Classification and Management of Fishing harbours

The classification of fishing harbours in India follows the pattern of classification of commercial ports which are classified as major ports and minor ports. Major ports are under the control of GoI and are regulated under the major ports trust act. Minor ports are for commercial activities of the maritime states and are under the control of the respective state Government. Following a similar pattern there are three categories of harbour facilities in India for fishing vessels. Major fishing harbours for use by fishing vessels going on deep sea fishing, minor fishing harbours developed under the respective state departments and fish landing centres where fishing or fish transport vessels discharge the fish and are usually under the control of the local bodies. Though efforts were made to upgrade physical and infrastructural requirements at fishing harbours, many of them are not properly maintained due to various reasons. Consequently, the sanitary and hygienic conditions in the harbours fall below the internationally accepted standards and fish leaving the harbours are of low quality. Implementation of a Food safety management system (FSMS) based on HACCP is believed to solve these issues. Leagal Background

Section 8.9 of the FAO Code of Conduct for Responsible Fisheries1 outlines the duties and

obligations of States with respect to the design and construction of harbours and landing places, as well as the establishment of an institutional framework for the selection or improvement of sites for harbours. The guidance to States is elaborated in Annex VI of the FAO Technical Guidelines for Responsible Fisheries, No.1, Fishing Operations, which sets out the procedures for the development and management of harbours and landing places for fishing vessels.2 Annex VI provides, among others, the standard procedures for management, environmental auditing, design criteria and education and training. The EU legislations dealing with food safety management systems are regulation 852/2004 and regulation 853/2004. The former is primarily concerned with the management and implementation of quality and food safety assurance regimes in food production including the application of HACCP principles. Section VIII of the directive (regulation 853/2004) is concerned particularly with fishery products. The other EU regulation that has relevance is regulation No 854/2004 “laying down specific rules for the organization of official controls on products of animal origin intended for human consumption”. History of food safety and Origin of HACCP

Food Safety is defined as providing assurance that food will not cause harm to the

consumer when it is prepared and/or eaten according to its intended use (WHO 1995). The worldwide evaluation and reorganization of food inspection and control systems geared towards improving efficiencies, rationalizing human resources and introducing risk analysis-based approaches resulted in the convergence towards the necessity to implement a preventative approach instead of the traditional approach that relied heavily on end-product sampling and

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inspection and that is HACCP. HACCP is an internationally recognized food safety management system and many countries have made it mandatory in their food production sector.

In India, compulsory quality control was first introduced for fish and fishery products meant for export under the export quality control and inspection Act 1963. The in-process quality control (IPQC) system introduced in 1997 followed by the modified in-process quality control (MIPQC) system, Self Certification (SC) scheme introduced in the late eighties and the HACCP based system, the “Quality Assurance and Monitoring System” (QAMS) which came under the Export of Fresh, Frozen and Processed Fish and Fishery Products (Quality Control, Inspection and Monitoring) Rules (1995) and founded on the then existing IPQC system by incorporating the requirements of both USFDA and the EU Directive 91/493 were all developments in the quality and safety front by India to keep in par with the developed nations. However, all these compulsory quality control systems implemented in the seafood export units could exercise controls from raw material purchase only, ignoring the primary landing centers which forced the exporters to take care of the quality of the fish they purchase. Many of them have own arrangements with the vessel owners. The Food Safety and Standards Act, 2006 consolidates the laws relating to food and established the Food safety and Standards Authority of India for ensuring availability of safe and wholesome food for human consumption and requires the need for HACCP system to be adopted by the food production and retail outlets in the country. The Pre- Requisite Programs

The HACCP which was originally designed as a food safety management system, further expanded in practice to include the quality and hygiene parameters also, reducing the effectiveness of HACCP as a food safety control mechanism which resulted in the genesis of a new concept, the Pre- requisite programs(PRP). The WHO has defined PRP as the “Practices and conditions needed prior to and during the implementation of HACCP and which are essential for food safety”. These programs include areas such as supplier control, temperature monitoring, personal hygiene standards, cleaning and sanitation programs, proper facility-design practices, equipment maintenance, and cross-contamination control and pest control programs. PRPs control the operational conditions within a food establishment allowing for environmental conditions that are favorable for the production of safe food.

Safety and Quality Management System The introduction of the two concepts HACCP and PRP, created big confusion in companies

regarding their relations, how they should be managed etc. mainly because of negative guideline factors and lack of understanding. In some countries, initially, it has been the practice to include quality issues and hygiene issues in HACCP plans which, in fact has led to the over complication of HACCP. The inclusion of CCPs in HACCP which are not true CCPs caused major problems in practice. Some companies developed both PRP and HACCP plans, yet failed to link the two systems. The HACCP evaluators found that here, the issues are either duplicated or missed due to assumptions that one or the other system already covers them. At this juncture, another school of thought evolved which indicated that the PRP can be used to work effectively with HACCP and a better approach is to control significant hazards with the HACCP plan and to keep generalized quality and hygiene issues to the PRP where they are less likely to cloud the HACCP plan or divert attention from the essential controls, the CCPs. The solution to overcome all such problems was

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recommended to be through the use of an integrated approach of management of safety and quality in a total quality management system. Consequently a few workers suggested a quality management system which takes into consideration all the controlling points, the safety hazards addressed through the HACCP system and the quality and hygiene issues met with through the PRP and can be achieved by managing both HACCP and PRP within a quality management system such as ISO 9000. Food Safety from the ‘Net to Plate’

The ‘Net to Plate’ concept with respect to capture fisheries is similar to the ‘Farm to Table’

concept in the case of culture fisheries. The present international markets demands that the fish sold is traceable not only to its country of origin but also the waters it was fished-in and the entire post-harvest infrastructure which handled the exported product viz; the vessel which landed the product, the harbour which handled the product and the entire cold chain; and inspection procedures are also expected to include harvest area, fishing vessels, landing sites, auction hall, transport facilities and the staff involved in these operations. Whether or not required by international regulations, good practices and conditions with regard to food safety should be in place as part of any operation. Safe food handling is the responsibility of each and every person in the food handling chain and negligence in any of these stations can have serious consequences on the final quality and safety outcome of the product. The fishermen, the primary processors, the retailers, all should take care to see that the food is kept safe as long as it is under their control. Moreover, the product should reach the end user within the shortest possible time. Therefore, it becomes significant and the need of the hour to assure food safety conditions in capture fisheries; onboard the vessel, in fishing harbours and landing centers, and the subsequent stages. All possible strategies for controlling the hazards present at the level of primary production should be adopted to ensure the safety of the consumer. Several countries have come up with guidelines for Assuring Food Safety Conditions in Capture Fisheries. Export Inspection Council (EIC) of India has has laid down regulations for the proper maintenance of hygiene and cleanliness for handling fish for export on board vessel and in the landing centres in parity with the international regulations. Document No EIC/F & FP/Ex.Inst./March/2012/Issue 4 ; Appendix D Deals With Requirements For Approval Of The Landing Centers / Fishing Harbours. / Auction Centers; Appendix E Requirements For Approval Of Fishing Vessels; Appendix- F , General Requirments For Approval Of Factory Vessels For Processing Fish & Fishery Products For Export And Appendix – G, General Requirments For Approval Of Freezer Vessles For Processing Fishery Products For Export (Annex 1). Food safety management system (FSMS) based on HACCP in Capture Fisheries

HACCP is a science-based system that aims to prevent food safety problems from occurring rather than having to react to non-compliance of the finished product. The HACCP system accomplishes this by identifying specific hazards and implementing control measures. Prior to the application of HACCP to any segment of the product-processing chain, that segment must be supported by PRPs. The establishment of PRPs will allow the HACCP team to focus on the HACCP application to food safety hazards that are directly applicable to the product and the process selected, without undue consideration and repetition of hazards from the surrounding environment. The PRPs would be specific to the individual establishment or vessel and would

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require monitoring and evaluation to ensure their continued effectiveness. PRP assures quality, whereas HACCP assures quality and safety.

The application of the HACCP system begins with the development of HACCP plan. It is a

systematic process, a sequence of twelve tasks has been described, in which after the first five steps, the seven basic principles of HACCP are included (CAC, 1997).

The process flow chart is a sequential listing of all the processing steps in the production

process. In other words, it is a schematic and systematic presentation of the sequence and interactions of the steps and indicates the direction of movement of the process or product. With respect to implementation of HACCP, the subsequent documentations can be based on the flow chart.

Hazard is a biological, chemical or physical agent or factor that cause an adverse health

effect (NACMCF 1992). For the purpose of HACCP, hazards only refer to the conditions or contaminations in food that can cause illness or injury to the consumers. An important aid to hazard analysis is the process flow chart which documents all the major steps in the operation. Hazard analysis involves the identification of hazards and assessment of the severity of the hazard. The severity of hazards and the probability of their occurrence is evaluated according to the epidemiological data about the foodstuff. Assessment of risk and severity makes the hazard analysis quantitative and thereby informative. Risk expresses the chance of a hazard occurring whereas severity relates to the magnitude of the hazard. “Risk” in relation to any article of food means the probability of an adverse effect on the health of consumers of such food and the severity of that effect consequential to a food hazard. “Risk analysis” in relation to any article of food means a process of consisting of three components, i.e, risk assessment, risk management and risk communication. “Risk assessment” means a scientifically based process consisting of the following steps:Hazard identification, Hazard characterization, Exposure assessment and Risk characterization. All the activities associated with harvesting, handling and storage on board, transportation to the harbor, unloading, handling, auction and storage in the harbor etc. should be evaluated. Activities like sorting, grading, washing etc. are classed as low risk; freezing, filleting etc. are classed as medium risk whereas cooking is considered as a high risk activity and in such cases more strict controls are required. “Risk communication” means the interactive exchange of information and opinions throughout the risk analysis process concerning risks, risk related factors and risk perceptions, among all involved and interested parties including the explanation of risk assessment findings and the basis of risk management decisions. “Risk management” means the process of evaluating policy alternatives in consultation with all interested parties considering risk assessment and other factors relevant for the protection of health of consumers and for the promotion of fair trade practices and even selecting appropriate prevention and control options. A CCP must be identified for each hazard identified during the hazard analysis step. To aid in deciding what operations are CCPs a decision tree has been developed (CAC 1997). To be a CCP, an operation must be such that appropriate action will prevent, control or minimize the hazard. If a hazard can be controlled at more than one place, the most effective place to control it must be chosen. Examples of control measures are listed below:

1. Biological hazards- Time/ temperature control, thermal processing, cooling and freezing,

hygienic practices, source control, drying, addition of salt or other preservatives etc.

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2. Chemical hazards – Source control (vendor certification and raw materials testing) and

production control (proper use and application of food additives etc.)

3. Physical hazards – Source control, production control, use of metal detectors, UV light etc.

Critical limit is the criteria which separates acceptability from unacceptability. Hence they must be associated with a factor which can be measured and monitored on a routine basis. Monitoring should be undertaken by persons involved in the operation which involves making visual observations, sensory evaluations, taking physical measurements and testing of samples. It should be specified as to who will perform monitoring, what will be monitored, how monitoring will be done and when monitoring will be done.

Corrective Action Procedures must be taken to rectify the situation and get the process back under control, when monitoring indicates deviation from the specified range or critical limits. All suspected products should be placed on hold until its safety is ensured. Corrective action is also important in the point of view of its importance in reviewing the process and preventing the recurrence of the deviation and the hazard.

The verification process assists in improving the HACCP system and determines whether the HACCP system achieves its goals. The questions which may be asked during the verification process include whether the correct CCPs are selected, have effective criteria for control been specified, are there control measures in place, are the monitoring activities effective, etc.

Record keeping assists in carrying out verification activities, trouble shooting, data analysis for production improvements and to review production history. Records like HACCP plan, Product traceability, records of CCPs monitoring, corrective action, nature of coding, analytical details etc. should be properly documented.

Pre-harvest and post-harvest hazards Pre-harvest hazards can be classified into the following

1. Biological hazards- Microbes, parasites, toxigenic animals,

2. Chemical hazards – Natural toxins, pesticides, heavy metals, antibiotic residues, cleaning

compounds,

3. Physical hazards – Stones, sand, mud, bones, metal fragments, glass.

4. Environmental hazards – Prohibited/endangered sps/area, undersize

The most significant pre harvest hazards are marine biotoxins (ciguatoxin, PSP, DSP etc.)

which are often heat-stable. Molluscan shellfish are filter feeders and toxins associated with the phytoplankton can accumulate and become concentrated in the bivalve molluscs. Scientific data has shown that when algal blooms producing marine biotoxins are present in harvest areas, toxins may accumulate in fish at a hazardous level and the only possible control measure is to follow good monitoring practices, check the identity of the used species.

Harvesting of endangered sps and/ or from prohibited areas, catching of undersize fish etc.

are all matters connected with food security issues and should not be mistaken for food safety issue. For U.S. federal waters, no molluscan shellfish may be harvested from waters that are closed to harvesting by an agency of the federal government. All molluscan shellfish must have

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been harvested from waters authorized for harvesting by a shellfish control authority. All containers of molluscan shellfish received from a harvester must bear a tag that discloses the date and place they were harvested (by state and site), type and quantity of shellfish, and information on the harvester or the harvester’s vessel (i.e., the identification number assigned to the harvester by the shellfish control authority, the name of the harvester or the name or registration number of the harvester’s vessel).

Harvest Onboard the Vessel There are separate definitions and hence regulatory requirements for traditional, freezer and factory vessels in the Regulation ((EC) No. 853/2004). Hence it is important to classify the vessel correctly. Traditional vessels are generally classed as low risk, and therefore, have fewer food safety requirements. Fishermen are exempt from the seafood HACCP regulation. However, although the legislation simplifies food safety requirements, it places a greater responsibility on the skippers or owners to ensure that the necessary measures are in place to assure food safety onboard their vessels. In some countries, therefore, the primary processors, who are generally the processors that off-load fish from the harvest vessels, demand recorded observations like video from the fishermen which focuses on the efforts taken by the primary processor as well as serves as a recorded proof of good harvest vessel practices and activities.

Fish are highly perishable foods and should be handled carefully and chilled without undue delay. Harvest vessels are the first and the most important segment in preventing scombrotoxin formation. As per FDA recommendations, whole, uneviscerated fish should be placed into the chilling medium not more than 9 hours after the fish dies. Removing the gills and guts of the fish eliminates a significant portion of the bacteria that cause scombrotoxin formation and hence the fish can safely be held longer before chilling, upto 12 hours after the fish dies.The time limit is shortened when either the water or air temperature are high because it takes longer to chill the fish and scombrotoxin forms more rapidly at higher temperatures.

Table 1. FDA recommended time-to-chill limits

Water/air temp (0Fahrenheit) Type of product Time to Chill(hours) 40 Whole,uneviscerated 9

>83 Whole,uneviscerated 6 40 Whole,gutted 12

Time of death is readily apparent when fish are captured alive and slaughtered aboard the fishing vessel. But, sometimes fish will die in the water before being brought aboard, in such cases, the fishermen will not know the precise time of death. A trawler will be landing live fish and so it is easy to arrive at the critical time to chill limit when the water temperatures are known, whereas in the case of other gears, the fishermen should record the time the net is fully deployed, the time the last fish from the net is safely stored in ice. The deployment of a longline typically take 3 to 4 hours, then allow a 6 hour soak, followed by another 3 to 5 hours to haul back the line. The time temp knowledge, type of gear used and method of capture are essential as the HACCP plan should include the time limit as part of the critical limit for the receiving critical

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control point. Since activities like sorting, grading, gutting, washing etc. performed on board the vessel are

classed as low risk type, the food quality and safety can be achieved through the PRP plan. PRP which outlines the minimum requirements for a harvesting vessel prior to the application of HACCP are Vessel design and construction, Design and construction of equipment and utensils, Hygiene control programs such as Cleaning and disinfection, Water and ice, Pest control, waste management, Personal hygiene and health, traceability and recall procedures, training and documentation etc. HACCP approach requires food products to be prepared or processed in certified plants and establishments for which it is essential that the plant meets minimal requirements in terms of layout, design and construction, hygiene and sanitation. The EIC of India has formulated guidelines pertaining to requirements for fishing vessels and is presented below.

Table 2. Requirements for approval of fishing vessels

1 Design and facilities. 1.1 Vessels must be designed and constructed so as to avoid contamination of fishery

products with 1.2 Surfaces with which fishery products come in contact must be of suitable

corrosion-resistant material that is smooth, non-toxic and easy to clean. 1.3 Vessels designed and equipped to preserve fresh fishery products for more than

24 hours shall be equipped with holds, tanks or containers for the storage of fishery products at a temperature approaching that of melting ice. These holds shall be separated

1.4 The holds shall be designed to ensure that melt water cannot remain in contact with fishery products. Holds has to be properly separated from engine

1.5 Containers used for the storage of products shall be such as to ensure their preservation under

1.6 Equipment and material used for working fishery products shall be made of corrosion–resistant

1.7 In vessels equipped for chilling fishery products in cooled clean seawater, tanks must incorporate devices for achieving a uniform temperature throughout the tanks. Such devices must achieve a chilling rate that ensures that the mix of fish and clean seawater reaches not

1.8 Fish receiving deck shall be smooth, clean and free from engine oil , grease, etc. 1.9 The artificial lights provided on the deck and in the hold shall have protective covers. 2 Good hygienic practices 2.1 Utmost care shall be taken while catching / storing / handling of fish to avoid

injury / damage to the animal. Even if spiked instruments are used for the moving of large fish or fish which might

2.2 The fishery products should not be dumped directly on the deck. Clean food grade polythene

2.3 As soon as the fishery products are taken on board, they must be protected from contamination and from the effects of sun or any other source of heat.

2.4 When the fishery products are washed, the water used must be either potable water or clean

2.5 It shall be ensured that equipment, containers and all the fish contact surfaces shall be periodically cleaned with potable water or clean seawater and

2.6 Fishery products other than those kept alive must undergo cold treatment as soon as possible after procurement, especially in case where the fishery products are to be stored for more than 8 hours on board 2.7 Ice used for chilling of products must be procured from EIA approved ice plants / establishments and shall be handled / stored hygienically to avoid

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2.8 Staff assigned for handling of fishery products shall be required to maintain a high standard of cleanliness for themselves and their clothes Persons liable to contaminate

2.9 Fishery products shall be handled / stored in hygienic manner to avoid 2.10 Cleaning products, toxic substances shall be stored in locked premises or cupboards.

2.11

Details of fishery products caught by the vessel and supplied to approved establishment(s) shall be given to hygiene inspector of landing site.

(EIC/F&FP/ Ex.Inst./March/2012/Issue 4) Post-harvest Food Safety in Fishing harbours and landing Centers

In a fishing harbor again, the activities carried out like sorting, grading, beheading, evisceration, washing, filleting, weighing, chilling, freezing, transporting etc. are classed as low and medium risk nature and hence achievement of food quality and safety can be achieved through strict adherence to the PRP plan. PRPs which outlines the minimum requirements for a major fishing harbour prior to the application of hazard analysis can broadly be classified into infrastructural, operational, auxillary and additional services. The infrastructural requirements are concerning location and surroundings, building and equipment, berthing facilities, landing quays, auction hall, chill room, toilets and rest place, pest control etc. water and ice, incoming fish, cleaning and maintenance, handling and storage, waste disposal, premises and house keeping are the operational PRPs. Workshop, net repairing yard, maintenance and repair, ice plant, fuel/oil pump, effluent treatment plant etc. are auxillary facilities while training, traceability, tracking and recall, surveillance and monitoring, documentation, internal audit and management review, security, control room, harbour management/monitoring cell, disaster management unit, etc. are managerial PRPs. A major harbour still can provide additional services like speciality production unit, dried fish storage, retail market, vehicles shed, laboratory, canteen, health center etc.

Meeting food export requirements has generally been a strong motivation to introduce

the HACCP system. The system is also capable of accommodating changes introduced, such as progress in equipment design, improvements in processing procedures etc. Therefore, fish and fishery products being a highly valued export commodity, the HACCP system can be expected soon implemented in the fishing harbours in our country. The harvesting and post harvest handling and storage operations of fish in a fishing harbor includes many points where control is needed, but most of these are not critical. Hence most of these can be controlled through the PRPs. However, it goes without saying that HACCP is a process control approach, whereas the activities in a fishing harbor are much more than that. Guidelines formulated by EIC towards requirements for approval is given below.

Table 3. Requirements for approval of the landing centers / fishing harbours / auction centers

1 Premises & Infrastructural facilities. 1.1 The Landing Site / Fishing Harbour of fish and fishery products shall be located

at a site ideal for the purpose and shall be free from undesirable smoke, dust, other pollutants and stagnant water. The premises shall be kept clean.

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1.2 The layout and design of landing site / fishing harbour shall be such as to preclude contamination. Adequate working space shall be provided for hygienic handling of fishery products.

1.3 Suitable covering shall be given at the landing site / fishing harbour to protect fishery products from environmental hazards such as sun light, rain, wind blown dust etc.

1.4 Floor and walls shall be smooth and easy to clean and disinfect. The floor shall have sufficient slope for proper drainage and to avoid stagnation of water.

1.5 Drainage lines of adequate size and slope shall be provided to remove waste water, the outlet of which shall not open to the sea near the landing berth.

1.6 Provision of adequate quantity of potable water or clean sea water shall be available in the landing sites for cleaning and sanitation.

1.7 There shall be provision for hygienic handling and storing of sufficient quantity of good quality ice.

1.8 Provision for crushing the ice hygienically shall be provided, as applicable.

1.9 Sufficient artificial lighting shall be provided and the lights shall be protected with suitable covering.

1.10 There shall be sanitary facilities at appropriate places for hand washing with sufficient number of washbasins, soap, disinfectants and single use hand towels.

1.11 Appropriate number of flush lavatories shall also be provided outside the landing sites / auction centers.

1.12 The utensils and equipment used to handle fish and fishery products shall be smooth and made of corrosion free material, which is easy to clean and disinfect and kept in a good state of repair and cleanliness.

1.13 Landing site shall be constructed in such a way to avoid entry of exhaust fumes from vehicles.

1.14 Suitable mechanism shall be adopted to prevent entry of birds / other pests inside the landing platform, auction areas and other storage areas.

1.15 There shall be a provision for lockable refrigerated storages for product declared unfit for human consumption and separate lockable refrigerated storage for detained fishery products.

2. Auction hall 2.1 Preferably, separate auction hall(s) may be provided, which is well protected

from the entry of pests/insects, for display and sale of fishery products. 2.2 Since, fishery products shall not be kept directly on floor, as far as possible,

provision may be given for raised platforms for display of fishery products, which are smooth, easy to clean and disinfect. However, instead of raised platforms, any other suitable provision can be made so as to ensure that fishery

3 Good Hygiene Practices

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3.1 Landing sites / fishing harbours shall be maintained hygienically. Cleaning and sanitation shall be implemented at all areas of the landing site on a laid down frequency to avoid cross contamination.

3.2 Landing site / fishing harbour / auction center shall depute a responsible, experienced person, as hygiene inspector, to ensure the implementation of cleaning and sanitation effectively and good hygienic practices. Hygiene inspector shall ensure the quality of fishery products meant for export and also adequate icing of fishery products.

3.3 Floors, walls, partitions, ceilings, utensils, instruments and other food contact surfaces shall be kept in a satisfactory state of cleanliness and repair.

3.4 The premises and all the surfaces that come in contact with fishery products shall be cleaned before and after each sale. The crates / utensils shall also be cleaned and rinsed inside and outside with potable water or clean sea water and disinfected before use.

3.5 Detergents / disinfectants used shall not have adverse effect on the machinery, equipment and products. They shall be stored in a suitable place away from fish landing area.

3.6 Sign boards prohibiting smoking, spitting, eating, drinking etc. inside the landing sites shall be exhibited at prominent positions.

3.7 Fishery products shall be properly iced using good quality ice made up of potable water so as to maintain the core temperature of fishery products below 4ºC. Refrigerated room of adequate size

for storing fishery products may be provided, if required.

3.8 Fishery products, ice, utensils etc. shall not be kept on the floor directly.

3.9 Proper waste management shall be adopted to remove solid and liquid wastes immediately after its formation so as to avoid cross contamination.

3.10 Adequate pest management system shall be developed to avoid entry of insects, rodents and other pests into the landing, auction and storage areas. Insecticides and other toxic chemicals shall be stored in lockable cupboards.

3.11 Separate area may be earmarked for storage of fishery products unfit for human consumption.

3.12 Workers engaged in handling fishery products shall maintain highest degree of cleanliness. They shall wash their hands properly before and after handling fishery products, ice and food contact surfaces.

3.13 Workers shall adopt good personal hygiene practices to avoid contamination of fishery products.

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3.14 Person responsible for hygiene shall ensure that employees are following personal hygiene practices strictly.

3.15 Unauthorized person(s) shall not be permitted to enter into the landing site / fishing harbour.

4 Inspection and testing

4.1 Person responsible for hygiene shall conduct random checking of fishery products meant for export for organoleptic / freshness factors, including the core temperature to ensure chilling of fishery products below 4ºC and maintain records.

5 Monitoring and Record keeping

5.1 Hygiene inspector shall maintain records of fishing vessels landed and variety-wise details of fishery products supplied by each vessel to the approved establishments.

5.2 He / she shall monitor the fishing vessels during berthing on a laid down frequency to assess the hygienic condition/ infrastructure of the vessel, quality/ quantity of ice used etc. and maintain records.

(EIC/F&FP/ Ex.Inst./March/2012/Issue 4) References/suggested reading FAO/IMO Guidelines Ref. 3 and 5.

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Bryan, F. L. (1981) Hazard analysis of food service operation. Food Technology. 35(2)

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CAC (1997) Codex Alimentarius Commission. Hazard analysis and critical control point (HACCP) system and guidelines for its application, In General requirements (food hygiene), 2nd edn; Supplement to vol. 1B, pp. 33–45 FAO/WHO

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Community Fishery Centres: Guidelines for Establishment and Operation – FAO

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Construction and Maintenance of Artisanal Fishing Harbours and Village Landings – FAO Training Series No. 25. Sciortino J.A., Food and Agriculture Organization of the United Nations, Rome 1995

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Resource and Energy Conservation through Hook and Line Fishing

R. K. Renjith

ICAR-Central Institute of Fisheries Technology, Kochi E-mail:[email protected]

Introduction

Hook and line gears consist of a minimum of two parts, a hook that is attached to a

monofilament line and artificial or natural baits used to lure fish to the hook (FAO, 2001). This type of gear is one of the most common fishing gears used by both artisanal and mechanized sectors (Kurien and Willmann, 1982). Hook and line is one of the best methods of fishing with regards sustainability as this method has little impact on the surrounding environment and the catch can be selective (Rouxel, 2017). For example, any fish too small, or not the right species can be placed back into the water, without harm. These gears make it possible to operate in places with rocky or uneven bottom where it is impossible to deploy gears like ring seine or trawls (Mathai, 2009). Hook and line gear can be classified based on the method of operation. They are hand lines, troll lines, long line, jigging line, and pole and line fishing (Burdon, 1951; Gabriel, Lange, Dahm and Wendt, 2005; Pravin, 2008).

Hand lines

Hand line fishing, or hand lining, is a fishing technique where a single fishing line is held in the

hands. One or more fishing lures or baited hooks are attached to the line. Hand lining is among the oldest forms of fishing and is commonly practised throughout the world today. This may be used to capture of all kinds of demersal fishes from motorized as well as mechanized vessels. The gear can be described as hook, fishing lure (or a fishing jig), sinker and float are generally attached to the line. Many hand lines use swivel to prevent excessive fouling and kinking of the line. Sometimes rollers are hauled over rollers on sides of vessel.

Generally the gear is made up of polyamide (PA) braided, twisted or monofilament line.

Diameter of line used for fishing is varying highly from 0.2mm to 1cm. Srivastava et al. (2002) recorded 1 to 2 cm thick nylon rope in operation as a fishing line in streams of the Kumaon Himalayan Region of India. On the contrary, in Ratnagiri, hand line with hook made up of PA monofilament twine with diameter varying from 0.23 to 1 mm and length ranging from 5 to 16 m was operated. In Car Nicobar, 3 to 20 m long monofilament line was used for construction of hand line (Ahmed et al., 2013). Whereas in north east India, a rod can been seen tied with indigenous fibre or cotton thread or nylon twine and the end was fixed to a hook (Gurumayum and Choudhury, 2009).

Troll lines

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These are lines with baited hooks that are dragged behind vessels called trollers. Trolling is

primarily used for surface and subsurface fish. Splashing or rippling of water produced by an object has led to some improvement in the hook and line techniques. It is practised in Androth island of Lakshadweep (Pillai et al., 2006) for catching tuna (Vinay et al., 2017). Troll lines vary from region to region but use both natural and artificial baits. A trolling line consists of a line with natural or artificial baited hooks and is trailed by a vessel near the surface or at a certain depth. Several lines are often towed at the same time, by using outriggers to keep the lines away from the wake of the vessel. The lines are hauled by hand or with small winches. A piece of rubber is often included in each line as a shock absorber. Trolling speeds vary depending on the target species, but generally are between 2.3 and 7 knots. Troll lines may be set for fish close to the surface or the lines can be weighted for fish at selected depths. Lines may be hauled in by hand or by mechanical means (i.e. hydraulics). At the end of each line there are a variety of embellishments – spoons, spinners, and feathered jigs, in addition to baitfish (Gabriel et al., 2005).

Longlines

Long lining can be used to target both pelagic and demersal fish with the lines being rigged and set at a position in the water column to suit the particular species. A basic long line consists of a long length of line, light rope or more common now is heavy nylon monofilament, the ‘main line’, this can be many miles in length depending on the fishery. To this main line, multiple branch lines with baited hooks on (snoods) are attached at regular intervals. This rig is set either on the seabed (demersal) or in midwater (pelagic) with a ‘dhan’ bouy at either end, and allowed to fish for a period.

Longlines can be further classified as 1. Set longlines: These are stationary lines that are

anchored to the vessel, the seafloor or to an anchored buoy. Setting can be practised either horizontally or vertically. 2. Drift longlines: these are attached to floats that drift freely with the ocean currents. Jigger lines

These are a specialized type of vertical line, fitted with specialized ripped hooks, used primarily in the southern hemisphere Squid fisheries and some northern Cod fisheries. Multiple hooks are evenly spaced along the main line, which is hauled in using jerky vertical movements. This movement simulates the realistic movement of common prey species of the targeted species. In squid fishery, lights are used to attract the squid towards the surface. As the line is jerked vertically, the squid attack the hooks and are either caught by the mouth or the body. Jigger lines are typically used by specialized jigger vessels, but may also be operated from other types of boats. Jigger lines are generally of two types hand operated and automated jigging machines. Hand operated jigger line employs a reel or drum on which the jigging line is rolled over. Multiple jigs are attached to the jigging line and the reel is released by rotating the reel or drum. In automated jigging machine the machine has two drums and one drum is driven electrically. The machine lowers and retrieves the line in predetermined speed. A wire mesh frame is positioned in such a way to collect the squids falling off the jigs slides directly into boxes on deck.

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Pole and line gear

The gear consists of a hook and line attached to a pole. Both artificial and natural fish are used to lure the prey. Poles are commonly made out of wood or fiberglass and can be operated by hand or mechanized. Albacore Tuna and other Tuna species are commonly caught by the pole and line method in commercial fisheries. Pole and line fishing can occur from the surface to great depths, the only limiting factor is the amount of line used. Pole and line fishing is extensively used in some areas such as Lakshadweep island of India, Japan, Maldives, Sri Lanka, California and Hawaii for catching skipjack and other species such as frigate mackerel, little tuna and bonitos. Bamboo poles are traditionally used of size ranging from 2.4 to 2.7m in length. A 75-90cm line is fastened to this pole. A 60cm wire leader bearing lure is attached to the end of this line to which a barbless hook is attached. Small fishes of weight 15-20kg are hauled by a single fisherman. In case of larger fish, a single leader is attached to two lines from two poles. The vessels use live bait and water shower to mimic shoal of small fishes to attract the tuna. Targeted species in hook and line fishery

Hook and line fishing is highly targeted fishing practice which manages to land high value fishes. Though a high variability in value of fish is observed, Indian waters have shown less diversity in hook and line fishing. Out of five methodologies discussed here, four of them except jigging has targeted tunas invariably all around the coast. More details on targeted species are given gear wise as follows. Long lining

In the Indian seas, longline fishery is mainly targeting yellowfin and bigeye tunas. As reported elsewhere (Shivasubramaniam, 1963; Pillai and Honma, 1978) the bycatches, especially sharks constitute a major portion of the longline catch in the Indian waters also. Mechanized sectors of Kerala, Tamil Nadu, and Andhra Pradesh rely on longlining for high value fishes like tuna, marlin, sail fish and sharks. In Kerala, landings from hooks and lines fishery contribute about 3.3% of the total fishery. Seerfish landings registered an upward trend with 83.3% increase from 2010 to 2011, out of which 54.7% was contributed by longline in Kerala (CMFRI, 2012). During 2011, 50.8% of elasmobranch catch was contributed by line fishing and grouper contributed about 15% by longline. In Tamil Nadu, 10.6% of seerfish, 1.2% of tuna and 4.2% of elasmobranchs were contributed by hook and line (CMFRI, 2012). In Visakhapatnam, annual catch of tuna recorded by hooks and lines was 2714 t during 2011 constituting dominant species, Thunnus albacares (53%), Katsuwonus pelamis (31%) and Euthynnus affinis (16%) (CMFRI, 2012). According to CMFRI (2012), a total of 29 longliners are operating in Kerala coast, 380 in Tamil Nadu and 21 in Andhra Pradesh during 2010 (Vipin et al., 2014). Handlining

A very popular method for catching big demersal fishes like emperor fishes (Lethrinids) and snappers (Lutjanids) in the coastal areas of Indian waters. Bottom handlining was carried out with ‘vallams’ towed by mother ships to the fishing grounds close to the continental slope (Medcof, 1956). Recently handlines are found to be operated by Thoothoor fishermen all around Indian coast. Deep sea going fishermen of Toothoor operates handlining for Kalava fish

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(Epinephelus sp.) from December to April from mechanized boats. Species like Selar crumenophthalmus, Decapterus sp., Auxis rochei, Auxis thazard, Epinephelus areolatus E. bleekeri, E. cholorostigma E. tauvina, Thunnus albacares contributes major catch from Indian coast (D’Cruz, 2000). Pole and line fishing

The pole and line fishing technique supplies 11% of global tuna (ISSF, 2013) and is considered as a best practice due to its high selectivity and low environmental impact (Gillet, 2011). 10% of the Indian Ocean tuna catch comes from small-scale pole and line fisheries operating out of the Maldives and Lakshadweep islands (Gillett, 2013), landing a majority of skipjack tuna (Katsuwonus pelamis) amongst yellowfin (Thunnus albacares), bigeye (Thunnus obesus), kawakawa (Euthynnus affinis) and Auxis spp. These fisheries utilize small planktivores from island lagoons and reefs as live-bait to target oceanic skipjack resources (Stone et al., 2009), thereby reducing the pressure on the sensitive coral reefs of their atoll ecosystems. Troll lining

This method is prasticed to a lesser extent in India. An established fishery of pole and line is practiced at Androth island of Lakshadweep. Troll line contribute only 3.3% of tuna landing of Lakshadweep. The catch is dominated by yellow fin tuna, frigate tuna, little tuna, skipjack tuna and other species like shark, seer fish and sword fish (Vinay et al., 2017). Other than India, Maldives and Sri Lanka has troll line fisheries for tuna species (Sivasubramaniam, 1985). Jigging

This methodology is solely aimed to catch cephalopods based on their feeding behavior all around the world. Countries like Japan, China Sea, New Zealand, Peru, Korea, Malaysia and Vietnam operate automated squid jigging for a wide range of cephalopods (Todarodes pacificus, Ommastrephes bartramii, Loligo bleekeri, Photololigo edulis, Nototodarus sloanii, Dosidicus gigas, Uroteuthis duvauceli, Sepioteuthis lessoniana, Sepia aculeate, Sthenoteuthis oualaniensis). Fish jigging is prasticed along North Pacific coast of Japan for Mackerel (Scombridae) and Hairtail (Trichiurus lepturus). Automated squid jigging is in experimental stage in India (Mohammed, 2016) whereas a few places like Ratnagiri, Vizhinjam, Kanyakumari, Palk Bay, Tuticorin and Gulf of Mannar- motorised crafts operates hand jigging seasonally. The catch mainly comprised of Sepia pharaonis, Loligo duvauceli, Sepia aculiata and Sepioteuthis lessoniana (Sujith and Desmukh, 2011). Hook and line fishing: bycatch scenario

Since the numbers of species caught are less in a single operation, average mortality rate is assumed to be less than other fishing methods considering population parameters. Line fishing catches desired fishes during operation and unlike trawls, it avoids contact with the sea bottom hence it is assumed that very few species are affected other than targeted species. In a multispecies fishery like India, bycatch reduction has always been challenge (Lobo, 2012). Since the selectivity of line fishing is prominent, concern for bycatch is considerably less alarming.

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The trolling method is used all around the world in fisheries targeting tuna, salmon (Salmo spp.), barracuda (Sphyraena barracuda) and others (Majkowski, 2003), with incidental capture of seabirds reported. In the Mediterranean, Cooper et al. (2003) reported that small Maltese vessels undertaking trolling for tuna, Bream (Dentex dentex) and other predatory fish killed 35 birds. Unpublished information in several countries reported captures of shearwaters (Puffinus carneipes and P. pacificus), Yellow-nosed albatrosses, Australian pelicans (Pelecanus conspicillatus) and boobies (Sula sp.) either by taking hooks or by colliding with gear and becoming entangled. Studies indicated minor implications when targeting Yellowfin tuna but major concerns (catch rate of 0.41 birds/day) when targeting Bigeye tuna. Many authors suggested that capture in this trolling occurs commonly and needs to be better studied, particularly when the vessels troll lines slowly (Bugoni et al., 2007).

Handlines are used to catch different species of tunas all around the Pacific Ocean, Indian

Ocean, Red Sea, Mediterranean and Atlantic Ocean, frequently around FADs. Handlines are also reported to be a selective fishing method (Majkowski, 2003). But high levels of incidental capture mortality of birds (0.61 birds/day) were reported in Atlantic (Cuthbert et al., 2003; Ryan et al., 2006).

Surface long lines for dolphinfish practised in the Atlantic had a high bycatch of seabirds

(0.147 birds/1000 hooks). However, the traditional pelagic longline captures seabirds during winter months (Neves et al., 2006), while the surface longline for Dolphinfish takes place during summer in the Atlantic (Swimmer et al., 2005). A range of characteristics including low depth, deployment during daylight hours, and use of small hooks make it particularly dangerous for seabirds by being available throughout fishing and not only during deployment as in the longline for Swordfish and tuna. Catch rate of sea turtles was also high in the surface longline for Dolphinfish (1.08 turtles/1000 hooks) comparable to rates reported in the pelagic longline fishery for Swordfish in the SW Atlantic of 0.68–2.85 turtles/1000 hooks (Domingo et al., 2006).

Sharks and cetaceans cause significant damage worldwide in pelagic longline fishery operations. Damages are in the form of bite-offs, loss of gear, catch displacement, reduced gear efficiency, and depredation of the catch (Yano & Dahlheim, 1994; Secchi and Vaske, 1998; Garrison, 2007). The experimental longlines operated in Indian waters showed a very high shark catch during the post-monsoon season in the Bay of Bengal (John and Neelakandan, 2004). Conservation of non-targeted resources

Major bycatch in line fishing are turtles, seabirds, sharks and non-targeted fishes. The most discussed case is the incident of turtles in tuna long line. There are many methods adopted by sector all around the world for the conservation of these resources. Methodologies developed specifically for each organism. These methodologies are listed below:

Avoid hotspots: Hotspots are the location where the unwanted species are caught in large quantities. There is currently no quantification of what constitutes a hotspot. This would be left to the fishermen to determine if they are fishing in an area that is resulting in the incidental capture of sharks, sea turtles, sea birds, marine mammals or unwanted fishes.

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Set operational depth to deeper or shallow waters: This may work in case of shark species which swim to the surface waters. Setting line deeper than 100m will avoid most of the species and only yellow fin tuna may come in contact. Use circle hook with offset: Circle hooks have a rounded shape with a point oriented toward the shank, which is different than the J hook that has a point oriented parallel to the shaft. Circle hooks are wider and therefore more difficult for sea turtles to become hooked on. The offset creates a larger gap between the point and the shank hence the turtles can escape from accidental hooking. Similar to other species, circle hooks are wider and more difficult for some marine mammals to bite and become hooked on. Bill fishes are also known to escape from circle hooks without incidents of hooking. Use of wider circle hooks in place of narrower J and tuna hooks to reduce turtle bycatch rates and mortality in longline fisheries has also been found to reduce seabird bycatch rates by about 80% (Gilman, 2011) Line weighting: Weights are added to the branch line so hooks are quickly deployed to the target fishing depths. This reduces bycatch of seabirds by moving the baited hooks out of the diving range of seabirds. The effectiveness of line weighting depends on the distance between the weight and the hook (a short distance accelerates the initial sink rate) and the amount of weight added (greater weight accelerates the subsequent sink rate). This mitigation measure must be used in conjunction with properly deployed streamer lines or night setting in case of seabird interaction. Using weight or lead swivels of minimum weight 45g within 1m of the hook may reduce sea turtle interaction also. Use of finfish bait: Using finfish instead of squid for bait has been shown to reduce sea turtle interactions. This may be more effective for leatherback sea turtles compared to other species. Using finfish instead of squid for bait has been shown to reduce interactions with some but not all shark species Night setting: Night setting is the practice of setting and hauling fishing gear between dusk and dawn. No modifications to fishing gear are needed and this has been proved to avoid sea bird interaction to logline. Shorter soak time: This reduces the amount of time the gear is in the water, reducing potential interactions. It also may reduce mortality in incidentally captured turtles because they remain hooked for a shorter period of time Adequate soak time reductions would be species/fishery specific. The challenging part is to determine soaking time for specific species with experimental fishing. Streamer line (tori or bird scaring line): This is a line with streamers that is towed from a high point as the baited hooks are deployed (usually near the stern). An aerial segment with streamers suspended at regular intervals is formed as the vessel moves forward, creating drag on the streamer line. The mitigation measure works by maintaining the streamer line over the sinking baited hooks, therefore preventing seabirds from attacking the bait and becoming hooked.

Conduct fleet communications: This will allow fishermen and policy makers to determine where marine mammal sightings may have occurred and move fishing locations when interactions occur

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Prohibit the use of wire leaders and shark lines: Shark lines are attached to the floats and stay above mainline of logline. Wire leaders prevent sharks from being able to bite through and escape after accidental capture. Shark lines may attract more sharks to the fishing gear. Removing the first and/or second hooks closest to the float in each basket: The hooks closest to the float fish in shallower water and therefore have a higher likelihood of incidentally capturing sea turtles. Hook-shielding devices: These are devices that encase the point and barb of baited hooks. This prevents seabird attacks during the setting process. Hooks are released after the hook has reached a minimum of 10m depth or has been in the water for a minimum of 10 minutes. The Hook Pod and Smart Tuna Hook are two devices assessed as having met ACAP (Agreement on the Conservation of Albatrosses and Petrels) performance requirements. Use ‘weak’ hooks: These are specially designed hooks that break or bend when certain amount of pressure is applied, allowing incidentally captured species the ability to escape. Mostly used in case of marine mammal incidents as they are stronger than fishes. Restrict the use of light sticks: This may reduce billfish interactions by lessening the ability to see baited hooks. Turtles are also found attracted to light sticks. Use of monofilament for the mainline and branch line: Monofilament line reduces the risk of entanglement compared to multifilament lines. Monofilament is less flexible, making it easier to release entangled sea turtles (i.e. reduces knotting of the line). Time/area closures: Time-area closures and restrictions on the timing of setting could further reduce seabird bycatch as these factors have been observed to have significant effects on seabird catch rates Cover the point of the hook: This will reduce the ability of sea turtles to bite and become hooked. Avoid using light sources: This may reduce sea turtle interactions by lessening the ability of turtle to see baited hooks. Fisheries certification: It is important to recognise and reward good fishing practices in the market place. Among the most popular seafood certification organisations is the Marine Stewardship Council. The Council certifies fisheries based on the sustainability of fish stocks, the level of environmental impact (one of the parameters is that the fisheries should have negligible/low levels of bycatch), and whether the fishery is being effectively managed. A fishery that comes close to meeting these criteria of sustainability is the pole and line skipjack tuna fishery in the Lakshadweep. However, it is important to recognize the dynamic nature of what constitutes bycatch and evolve incentive systems which recognise the moral, social, and economic implications of bycatch along with its ecological impacts. It is equally important to understand that certification alone is not likely to bring about major improvements in the conservation of bycatch species. So far certification has primarily been effective in raising awareness among consumers (Ward, 2008). Its shortcomings are that it is seen primarily to market opportunities,

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and has rarely, if ever, helped the recovery of depleted species (Jacquet et al. 2009; Jacquet et al. 2010). Hook and line fishing: insight into advantages

Hook and line fishing is more selective than other types of fishing in terms of species and

size, and provides high quality fish (Erzini et al., 1996). The method can be used in spawning fish as they normally only bite after completion of spawning (Farmer et al., 2017). Lines are set for a relatively short time so that any unwanted species can often be returned live to the sea. Advantages of hook and line fishing are listed below. Quality of end product: while comparing meat quality from hook and line fishing and trawl caught fishes, line caught fishes exhibit firmer as well as whiter meat. The better quality may be due to better bleeding and less compression damage. Both the compression damage and the poor bleeding out are caused because trawling brings up from five to twenty tons of fish onto the deck each time, while with long-lining the fish are brought on board one by one. Lower fuel consumption: A significant advantage that longliners have over trawlers is the relatively low fuel consumption per unit of catch. For example, it was established that a trawler expends 0.6-1.5 tonnes of fuel per tonne of raw fish caught, while a longliner expends 0.1-0.3 tonnes (Karpenko, 1997; Makeev and Shentyakov, 1981; Pavlov and Makeev, 1987; Glukhov, 1994; Chumakov and Glukhov, 1994а, 1994b; Sorokin and Chumakov, 1995). With regards the amount of fuel used over time, the longliner spends 2.7 times less fuel every hour than a trawler (Zherebenkova and Makarova, 1990). The results of modern-day research in the Barents Sea show that a longliner spends 0.3-0.6 tonnes of fuel per tonne of raw fish caught (Grekov, 2007a). This is approximately 20-40 % of the fuel consumption of a similar type trawler (Bjordal and Lokkeborg, 1996). Species selectivity: In general, neither the trawl nor the longline can be considered as fishing gears that have a high selectivity towards some species of fish. Trawl can hardly be called a selective fishing gear as it takes almost everything that comes into a forenet (Bjordal and Lǿkkeborg, 1996). As for the longline, it is more selective because of its passivity. The catch depends mostly on the behaviour, biology and physiology of the fish. In particular, most fish cannot be caught by a longline as they are simply unable to swallow a hook (Lokkeborg, 2000). According to the work carried out at Barrent Sea, twenty-nine species of fish are harvested by longline. When carrying out trawler-acoustic counting of ground fish stocks, up to 70 types of fish were recorded in trawls (Grekov, 2007). Size selectivity: As the number of hooks on a longline is limited, the hooking of a large fish reduces the number of free hooks and so lowers the chances of catching juveniles. Furthermore, the hook itself is selective regarding fish size as small-sized fish can swallow a baited hook of no larger than a certain size. By changing the size of the hook and bait, therefore, one can satisfactorily control the volume of by-catch of small-sized fish (Grekov, 2007). Value of fish products: In general, the larger the fish, the higher its value. There are more large fish in logline catches and longliners tend to catch more products of large size. Consequently, more income is generated. According to verbal information provided by ship owners, the market

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value of fish produced by longliners is 15-20 % higher than for trawlers, largely because of the higher quality of product harvested by longliners.

Energy efficiency in hook and line fisheries: key areas to aim: The significance of energy and fuel in the fisheries sector and its vulnerability to changing energy supplies and prices have highlighted the need to review the sector’s energy and fuel needs and interactions, and their future trends. This needs to consider different areas and parts of the sector to and mitigating the effects of increased energy and fuel costs. Data acquisition, energy management and control systems and energy audits

With the aid of proper tools like sensors and data loggers, energy consumption can be

measured. The integration of data collection with criteria settings may allow estimation of relationship between speed and fuel consumption for vessel. A more complex system should be able to optimize aspects as the electricity consumption also. An energy audit, which requires extensive expertise and a good data acquisition, may propose solutions for each vessel. It is a necessary step to reduce energy consumption of existing vessels. Transparent energy audits should be promoted, defining the existing “base line” in terms of energy efficiency and advising about how to improve. Propeller optimization

Fishing boats are often equipped with propellers not matching correctly their needs, despite

this is a critical aspect in fuel consumption control. Interventions frequently focus on engines, but some experts consider this is probably not the best factor to influence on. However, it appears to be no awareness about the importance of a correct propeller selection, and propeller for specific fishing practices need to be developed. The correct choice of the engine is critical for fuel consumption. In particular, engines have poor performance when working under low load. A configuration to consider is the use of two different engines when two different regimes are frequently used. In addition to possible improvements in design and maintenance, proper selection and modification when necessary are important. In some vessels, the choice of two gear ratios could be a good option. Alternative fuels and complementary energies

It is necessary to study the economic and energetic feasibility in order to obtain complete

information and offering energy-efficient solutions to the energy consumption of the fishing vessels. In this context, the principal aims are to analyse and assess, through feasibility and techno-economic studies, the potential use of other fuels, and/or alternative energy for fishing vessels. Main fuels to consider are: LNG, CNG, LPG, hydrogen, biofuels, and syngas. Main alternative energies to consider, usually as auxiliary energy, are: wind turbines, sails and solar energy sources. Modifications in the vessels

Design technologies must optimize energy consumption. Computer simulation methods

and testing of models can be improved, but especially should be more widely used in fishing

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boats. Maintenance of the ship painting in contact with water can help reducing friction and therefore reducing fuel consumption. The design of bulbs may be an option on ships already constructed, but changing hull configuration could be the most expensive action, and current regulation is a barrier. In any case, correct data acquisition would be crucial in order to suggest and assess hull modifications. Energy for uses other than propulsion

Improvements in electricity consumption management would allow using engines of lower power, at higher load. This greatly reduces consumption. Generating electricity with a part of the propulsion engine reduces consumption as well. The residual heat from the propulsion engines contains more than 60% of the energy of the fuel. This energy is in the exhaust gases, and in the water used for cooling the engines. Some of this energy can be recovered for heating water (boiler), cooling in refrigeration room and desalination of seawater to obtain potable water. The use of electric consumers (such as kitchens, heating and/or cooling systems, desalination systems, lights, deck machinery (hydraulic, electric), pumps, etc.) must be minimised and correctly regulated. It is recommended to explore possible advantages derived from converting hydraulic actuators, or other systems, into electric ones (example: an electric rudder system works just when the movement is needed, whilst hydraulic systems include a pump working consistently). Efficient steering and navigation

Through efficient steering and navigation, a fishing operation can achieve lower fuel

consumption by introducing variations on the way of storing, way of processing and of transporting fishes. It is necessary to study the economic cost of implementing the different proposed models to assess their actual implementation capacity

Conclusion

Line fishing methods especially longline and pole and line widely used in Indian waters has advantages in biological and economical aspects as discussed earlier. Considering the current production from line fishing where tuna is targeted, production level has to fill in the huge gap with estimated potential of tuna from coastal fishing and island fishing. However, it is also to be noted that line fishing has the clear drawback of needing to use additional biological resources in the form of bait especially live bait for pole and line fishing. The large scale development of the line fishery is one of the means of optimizing exploitation of resources from Indian waters. At the same time, it is necessary to understand that development of the fleet must not only be aimed at increasing size but also at increasing efficiency. References/suggested reading Ahmed, S.K.Z., Ravikumar, T., Krishnan, P. and Jeyakumar, S. (2013). Traditional fishing crafts and gears

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Importance of Fish Behaviour Studies in Fishing Gear Design Madhu V.R.

Fishing Technology Division, ICAR-Central Institute of Fisheries Technology, Kochi E-mail: [email protected]

Introduction There has been a paradigm shift in the philosophy of fishing, primarily due to the alarming rate of decline of major fish stocks and secondly due to the improved understanding of habitat and ecosystem impacts of fishing. As a corollary to the developments in the fishing sector in the last decade, the priority of research in fishing technology now is towards conservation and development of fishing gears and methods, that least affect the fish stocks, habitats and the ecosystem. Sustainable capture fisheries would mean selective fishing using fishing gears, with least impact to the non-target organisms and other biota, which, would require an in-depth knowledge of the behaviour of the organisms that are targeted and non-targeted. Therefore, knowledge of the behaviour of fish in relation to fishing gear and fishing methods is a pre-requisite to design, construct and operate responsible fishing gears. Studies with conclusive results on the behaviour response towards stimuli associated during fishing are very limited and the problem of multi-species fisheries further baffles the problem of selective capture in fishing gears. Experimental studies to understand the behaviour of fishes near fishing gear are very few, and this is due to the inherent difficulties in recording and studying behaviour in the actual field conditions and the huge cost involved for studying behaviour of fish near the gear, particularly for active gears like trawls. A large body of work exists, on development of selective gears mostly developed based on trial and error methods, by conducting experimental fishing and studying the species assemblage structure. However, the gears and other technical devices are not often designed based on the behaviour ecology of the species or targeted group and hence tend to non-selective in most cases. The behavioural ecology and the knowledge of the underlying basics of responses to stimuli, associated with fishing, if considered, can help significantly in design of gears that have better species and size selection properties. The knowledge of the behavioural responses of targeted species to stimuli associated during fishing and its field level application is a relatively new field in the Indian scenario. Development of responsible fishing gears to reduce bycatch and discards is the mainstream of marine capture fisheries research and the research especially related to fish reaction to fishing gear has flourished, but mostly in controlled conditions, owing primarily due to the cost considerations and difficulty. Fish behaviour on a broader sense, can be defined as adaptation of fish to external and internal environments and to natural and artificial stimuli. Fish behavior in the context of fish capture, entails the reaction of fish to the different physical and chemical stimuli associated with a particular gear and its operations and the reaction, which the fish makes in relation to movement and distribution. The importance of fish behavior in understanding and improving size and species selectivity for sustainable harvest of resource has encouraged applied fish behavior

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studies in the context of fish capture. Though there are a large number of stimuli that lead to an effective capture, a strong background on the visual capabilities of the fish that being targeted is the most important input for studying the behaviour of fish. Vision and its applications in fish capture Understanding visual characteristics of fish is an important component in understanding the fish capture process and interactions between fish and fishing gear. While the structure of the eye is well known and mechanisms of vision have been described for a number of fish, many commercially important marine species have received little attention. Despite many years of research into the visual systems of fish, detailed knowledge and understanding of the role of fish vision in their reaction to fishing gears during capture processes needs further research. Most fish species can distinguish colour by the use of red, green, and blue sensitive cones. At least two types of cones are required for colour discrimination, while some freshwater and shallow – living marine species have the capability to detect ultraviolet radiation with a fourth type of cone. Electroretinogram (ERG) is used to monitor the response of retina to stimulation by different wavelengths of light (i.e., color) and to determine spectral sensitivity of fish eyes. Photosensitivity is the ability of fish eye to receive light and to get visual information in ambient light conditions. Light intensity varies with water depth, time of day, and transparency or turbidity of water. To allows fish to function visually over awide range of light intensities in the natural environment, functional changes are made by shifting of positions of rods and cone cells in the retina. Different fishing gears provide a different contrast image according to ambient light conditions, gear type, and the visual sensitivity of the fish. The contrast of an object against the water background is more important than the brightness of the object (Wardle, 1993). A moving image is more important to fish than a static one and detection of movement is dependent on visual acuity and persistence of time – which is the time taken to process the image by the organism. The flicker fusion frequency (FFF), which is the frequency at which flickering images fuse to produce a continuous image, is dependent on light intensity, temperature, and duration of the flash. Fish can detect motion at a wide range of light intensities from 10-7 to 10-14 lux (Protasov, 1970) and as light intensity increases, the sensitivity to detection of an image is enhanced and decreases with decreasing light. Behavioural techniques to investigate FFF and visual acuity is by optomotor response, which is the movement of the eyes, head, curvature of the body or trunk, or movement of the entire animal in response to follow a moving image (Sbikin, 1981). Comparative studies have shown that Elasmobranchs and species living in low light conditions have lower FFF, when compared to fishes that live near the surface. The detection of movement has important implications in how fish reacts to fishing gears, particularly in active systems like trawl gear, where the fish holds station with the gear components like floats, ropes and meshes until it becomes exhausted, by means of herding and optomotor responses. The visual contrast of the fishing gear against the background is more important that the brightness of the gear underwater. It is understood that there is a complex relationship between colour and contrast of gear components, ambient light intensity and quality of water, but in general it is understood that light coloured netting panels are more difficult to detect against a bright back ground because of low contrast and reverse for materials that strongly contrast with their surroundings, when viewed (fig. 1).

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Fig. Contrast of white, grey and black twines hung vertically in water in relation to viewing

angle (Source: He, 2010)

Swimming speed

The speed of swimming is an important metric that influences the catchability of the species. There are a large number of body shapes in fishes and swimming is a direct determinant of the body shape of the organism. Swimming again is an energy dependent activity and hence has positive correlations with sustained swimming, which is very important in case of active swimming gear like trawls. Quantification of the swimming speed of targeted fishes is a very important metric that can help in designing the gear and has significant impact on the fuel consumption in an active fishing gear. Swimming involves large expenditure of energy and hence will also affect the quality of harvested fish. Energy consumption increases with the type of fish and also the speed with which the fish swims. The highest level of energy consumption measured in fish are about 4W/kg (Videler, 1993). There are two types of swimming noticed in fish: sustained swimming speed and burst swimming. Sustained swimming speed involves regular swimming speeds at constant speeds, whereas burst swimming involves sudden spurts, which often involves very high demand on energy. The energetic cost of swimming is the sum of the resting or standard metabolic rate and the energy required to produce thrust. Expressed in watts (joules per second), it increases as a J-shaped curve with speed in m/s (Fig.1) The exact shape of the curve depends mainly on the species, size, temperature, and condition of the fish. Owing to the shape of the curve, there is one optimum speed at which the ratio of metabolic rate over speed reaches a minimum. This ratio represents the amount of work a fish has to do to cover 1m. To make comparisons, the optimum speed (Uopt), where the amount of energy used per unit distance covered in the minimum, is used as the benchmark. Fish use an average of 0.07J/N to swim their body length at Uopt. Temperature has a profound effect on the swimming capability both with regard to speed and with regard to endurance and maximum swimming speed doubles with every 100 increase in temperature. It is usually difficult to derive this metric is field conditions and research is often conducted in circular tanks (Fig. 2) The Uopt speeds of some commercially important species are shown in Table 1.

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Fig. 2 Theoretical curve of the rate of work as a function of swimming speed. The amount of work per unit distance covered (J/m) is at a minimum at Uopt.

Fig. 3 Moving gantry system installed at ICAR-CIFT for studying swimming speed of fish

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Table 1. Maximum sustained swimming speed (Umax) of some marine species (source: He, 2010)

SL.No SPECIES LENGTH (CM)

U Max (Cm/s) U MIN (L/s)

1 Atlantic cod 40 42 1.1 Gadus morhua 49 45 0.9 2 Atlantic cod 36 75 2.1 Gadus morhua 36 90 2.5 3 Atlantic herring

Clupea harengu 25 102 4.1

4 Atlantic mackerel Scomber scombrus

31 110 3.6

5 American shad Alosa sapidissima

42

6 Haddock Melanogrammus aeglefinus

17 44 2.6

Melanogrammus aeglefinus 24 53 2.2 7 Jack mackerel 14 90 6.4 Trachurus japonicus 21 90 4.3 8

Japanese mackerel Scomber japonicus

10 99 9.9

9

Red fish Sebastes marinus

17 52 3.1

Sebastes marinus 16 52 3.3 Sebastes marinus 16 52 3.3 10

Saithe Pollachius virens

25 88 3.5

Pollachius virens 34 100 2.9

11

Striped bass Morone saxatilis

42-57

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Hearing in fishes and its application in fish capture Sound travels at a speed of about 1500 m/s underwater and it can be used to control fish behaviour over a longer distance compared with chemical or visual stimuli. There are several methods, that use sound in fishing operations to attract fishes. It is recorded that fish schools can be driven into the set-nets by vocal sound of dolphins and yellowtail (Seriola quinqueradiata) can be attracted from the deep layers by the swimming and feeding sounds of its conspecifics. In Japan, acoustical signals are used to attract demersal fishes like red sea bream, this traditional method is called “boko”. This device consists of a conical shaped lead that has a hole at the bottom that produces sounds greater than 100 dB. Sound has been used as an active guidance method to transport fish over long distance for transport of fish seedlings to a desired location in sea without physical handing (Anraku, et al., 2006). The studies using sound as an attracting device is mostly being used in aquaculture facilities, where certain amount of conditioning would be required, which would not be easily possible for wild fish, however traditional methods still employ sound for capture. It has been hypothesised that sound could be an important factor in FAD based fishing, in which the underwater sound generated by the materials, could act as an acoustic sensory cue for fishes to aggregate. It has been recently understood that the reaction of fish to an approaching vessel follows similar responses of that of a prey fleeing from predator. It has been reported that cod were capable of initiating avoidance response at distances ranging from 470 m to 1470 m from the approaching fishing vessel. The “butterfly pattern” produced in either sides of the vessel, as a result of hull’s ability to shadow propeller cavitations, produce large lobes of high-intensity noise. Misund, 1994 has shown that this intense outwards movement of sound attracts fish inwards towards the vessel track, which would be favourable in case of trawling often called as “Pursuit effect”. Sound is also increasing being used to deter Endangered threatened and Protected (ETP) species form commercial gears, like gillnets and purse seines. Pingers , which produce sounds at frequencies that harass cetaceans are already in market and are effectively being used in different fisheries. Habituation is one problem that is being encountered when these devices and the efficacy is found to decrease with regular use of these deterring devices. Olfaction in fishes and its role fish capture The relative importance of the sensory modalities differ among species, and depends on the basis of prey preferences, the relative size of the sensory organs, brain anatomy, diel activity rhythms and visual stimuli. Olfaction as a stimulus is being used increasingly in the long lines and trap fishery world over. Since this capture process depends on the odour plume concentration and its direction, the swimming speed and the activity of the fish also depends on the efficiency of the fishing method. Larger fast swimming species have higher probability of encountering the stimulus. Using dispersion models, it is understood that fish responds to thresholds to bait odour from 10 m to several kilometres, depending on the state of food deprivation, rage of attractant release from the bait and current velocity. Food deprivation is found to have significant effect on the odour tracking ability of fishes, with a study showing increase in attraction of feed deprived

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sablefish by factor of 57 over that of a fish fed to satiation. Rheotaxis also is an important factor in fishing methods using olfaction as cue, since flow pattern would disorganise the fish that is actively searching for the source of the plume. So, it is suggested that it would be beneficial, to develop artificial baits that would release plumes at a high rate to attract fishes from long distances and then sustained release of plumes to allow the fish to get close to the source. The attraction towards baits, can also be effectively used for exclusion of non-targeted species like sharks in long lines. An artificial bait using squid liver developed for tuna longlining and tested off the Hawaiian Islands, showed significant reduction in the shark bycatch, with catch rates that were 67% lower than with traditional squid bait (Januma et al., 2003). Other examples of using this technique included reduction in sea turtle bycatch in US Atlantic swordfish fishery, using mackerel baits. Fish behaviour in response to bycatch reduction devices (BRD) The behaviour of fishes to these devices has been thoroughly evaluated in many cases and is known to be influence by a variety of intrinsic factors such as physiological condition, motivational state, fish size, visual ability and extrinsic factors such as ambient light conditions, water temperature, BRD design, position and orientation. A general concept is that the variation in behaviour of species is highly variable and many non-targeted species seem to actively seek areas of reduced flow from which they could prefer to swim actively to freedom. Though evidence are not so conclusive, it is considered that upward excluding grids improve fish exclusion rates because downwelling light is reflected from bars of the grid and this increases the distance at which grids becomes visible and hence the escape from the grids. It is argued that for an effective exclusion to happen in case of fishes, the water flow in and around a BRD should be little more than 0.4 m/s. This flow is particularly effective in shrimp trawls, for exclusion of fish bycatch from the trawls. Overcoming the optomotor reflex to facilitate fish escapement has to date not been effectively achieved and also requires further research. Reducing the visual stimulus (contrast) of the trawl extension, codend, and BRD is an obvious first step but requires a greater understanding of the visual capabilities of fish under a range of ambient light levels encountered in the fishery and their response under these various conditions. Escape vents in pots have been found to be very effective in release of juveniles that enter the trap and creation of turbulence in the region of the escape vents is found to be very effective for fish to find the vent. Conclusion Fishing is a complex process which involves the fish, the gear and the associated stimuli in the environment and capture is the result of the complex mix of these factors acting in tandem or individually. Light and vision; sound and hearing; water current and rheotaxis; and temperature are the main factors that affect the behaviour responses of fishes and these factors may act separately or simultaneously and is often difficult to “tease apart” the individual affects. The

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responses of the individual fish to the external stimuli and its capabilities to counter the external influences further makes the problem of studying response of fish to stimuli very perplexed. The overarching role in the recent years by fishing technologist has been to design and develop fishing gears with conservation as priority. Therefore, knowing how fish react to different types of stimuli is critical to understanding, how they are captured in different fishing gears and also how this process can be modified to allow undersized and unwanted fish to escape from different fishing gears. Quantifying the response of fish to all the stimuli is difficult to imitate on field and hence some of the factors (extrinsic/intrinsic) that influence the behaviour of fishes in the capture process can be imitated in the laboratory using suitable techniques. Among the many intrinsic factors, fish swimming speed is one for which estimates are available for many European fish species, but such information is lacking in the Indian scenario. In-situ studies in traps, though much easier to assess and quantify, has limitations with respect to quantifying the odour plumes though. The shape and size of the mouth and the escape vents, can be determined with good accuracy using tank based studies for traps. Studies that correlate behaviour with designing of fishing gear is very limited in fishing technology, but this is an important information that can help in designing and developing fishing gears that are responsible. References / Suggested reading Pitcher, T.J. (Ed.) 1993, Behaviour of Teleost fishes 2 nd edition. London: Chapman & Hall, 559 p.

Pingguo He (Ed.) 2010. Behaviour of marine Fishes – Capture processes and conservation challenges, Wiley-Blackwell, 386 p.

Videler J.J. 1993 . Fish Swimming . London : Chapman and Hall . 260 p.

Januma S , Miyajima K and Abe T . 2003 . Development and comparative test of squid liver artificial bait for tuna longline . Fisheries Science 69 : 288 – 292.

Misund OA . 1994 . Swimming behavior of fi sh schools in connection with capture by purse seine and pelagic trawl . In: Fern ö A and Olsen S (eds). Marine Fish Behavior in Capture and Abundance Estimation . pp 84 – 106 . Oxford : Fishing News Books.

Sbikin YN . 1981 . The optomotor reaction and some characteristics of the vision of young sturgeon . Journal of Ichthyology, 21 : 167 – 171 .

Protasov VR . 1970 . Vision and near orientation of fish, Trans. by M. Raveh for Israel Program for Scientific Translations. Washington, DC : U.S. Dept of Commerce . 175 pp.

Wardle CS . 1983 . Fish reaction to towed fi shing gears, In: Macdonald AG and Priede IG (eds). Experimental Biology at Sea . pp 168 – 195 . London : Academic Press .

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Sustainable Fishing Methods for Inland Water Bodies M.P. Remesan



Introduction Total world inland capture fish production was 11.63mmt in 2016 and China was the

leading nation followed by India with 1.46 mmt. Inland waters include freshwater and brackish water bodies in the form of rivers, reservoirs, lakes, backwaters, mangroves, estuaries, tanks, ponds, paddy fields, wetlands, etc. India has vast inland resources in the form of rivers and canals, 1,97,024 km; reservoirs,3.15 million ha; ponds and tanks, 2.35 million ha; oxbow lakes and derelict waters, 1.3 million ha; brackish water, 1.24 million ha and estuaries, 0.29 million ha. Inland water bodies include fresh water and brackish water areas. The river systems of the country is classified into five groups namely Ganga, Brahmaputra, Indus, Peninsular east coast river systems and west coast river systems. It comprises of 14 major rivers, 44 medium rivers and several small rivers and streams.

Fishery resources include 2546 species so far listed 73 (3.32%) belong to the cold

freshwater, 544 (24.73%) to the warm fresh waters, 143 (6.50%) to the brackish waters and 1440 (65.45%) to the marine ecosystem.

Lakhs of people are engaged fishing and allied activities and earn their livelihood from the

inland waters in our country. Currently these water bodies are under stress due to dam construction, siltation, pollution, land reclamation, water abstraction, etc., which adversely affected the fish production and fishery collapsed in several water bodies. Ganga action plan launched in 1986 with the main objective of pollution abatement, to improve the water quality by treatment of domestic sewage and industrial chemical wastes is a glaring example. Excess capacity and destructive fishing practices are other major reasons for declining fishery resources in inland waters.

Fig. 1. Chilika lake

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Since the capture fish production from the marine waters are declining inland sector is in

the focus. Further aquaculture activities, especially shrimp and carp farming are taken up in a big to meet the increasing demand for fish.

Pulicat lake

Among the native fauna most of the fishes are permanent dwellers and others are migrant species coming from the marine or fresh water bodies. Most of the fishes are native species and others are exotic which are accidentally or otherwise introduced into the system. Exotic species are harmful to the native fauna. Occurrence of African catfish in the inland water bodies is a good example. Immediately after the flood in Kerala fishermen had good catch of several exotic fishes like paccu, gourami and arapaima.

Fig. 3. Green mussel seeds collected from the sea is introduced into estuarine zones of rivers in Kerala for on bottom farming

Variety of fishing gears are in use and there is no proper licensing and controlling

mechanism. In the numerous water bodies inhabiting wide range of species and several types of fishing communities around, various types of fishing gears and methods are employed for fishing in the inland sector. The different fishing craft and gears operated in the inland water bodies are described below.

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Fishing craft Variety of fishing craft are in operation in the inland waters, which include a piece of log

or an inflated rubber tube to motorized FRP boats, depending on the type of fishing and nature of water body. In reservoirs bamboo raft, coracles and inflated tubes are common. In larger water bodies like Pulicat lake catamarams are used for cast netting and motorized FRP canoes are used for seine netting. In Chilika lake sail is used for wind assisted navigation in wooden canoes. Raft

Bamboo poles are tied together with help of rope keeping all the lower end of the trunk towards the stern side. These rafts are about 6-10 m in length and 1.5 to 5.0 m wide. It is operated with the help of bamboo poles or oars in the sluggish rivers, floodplain lakes and in some reservoirs. The life span of this raft is about 1 to 2 years. Wooden raft and banana rafts are also made in some areas. Coracles

Coracles (Fig. 5 & 6) are primitive, light, bowl-shaped boats with a frame of woven

grasses, reeds, bamboo or saplings covered with sheets. Coracles are mainly used in reservoirs and backwaters in the southern regions of the country. Coracles are about 2-2.5 m in diameter with the greatest diameter across the centre. The bottoms of the boats are covered with few layers of plastic gunny bags or with plastic sheets and is tarred to make it waterproof. Coracles are steered and propelled using a single paddle.

Fig. 4. Coracle of a migrant fishermen family from Karnataka Canoes

Dugout canoes are mainly made from a single large log by scooping out the wood with the help of a small hand spade. The length of this boat ranges from 4 to 8 m. In shallow water bodies it is operated either by a bamboo pole or by an oar by 2 to 3 persons. Fishing gears like traps, gill nets and hook and lines are operated from this canoe.

Plank built canoes are predominantly used in rivers and reservoirs. They are of different

types and vary widely in size and shape depending on where they are used and the type of fishing to be carried out. These types of canoe are operated by oar and in case of shallow water bamboo poles are also used. Sometimes canoes are provided with arch-shaped roofing made of

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bamboo mat or polythene sheet which provide shelter to the fishermen. Coat tar, indigenous preservatives and FRP sheathing is used in canoes to extend the life.

Fig. 5. Wooden plank built canoes in Chilika

FRP canoes are also used for fishing in the inland waters. Its smooth finish and light weight enables the fishermen to maneuver easily in the river. Fishing gears

Diversity of fishing gears are more in inland waters than in the sea. Hook and line, cast

net, traps, drag nets, gill nets and seine nets are the most popular gears. Hand picking and other primitive tools like spears and arrows are still in use in some pockets. Nylon monofilaments gillnets are the most predominant fishing gear across the sector. Fish traps are usually made of natural biodegradable materials, whereas all kinds of nets are made synthetic materials. Proliferation non selective fishing gears like small mesh gillnets, seines and stationary bag nets is a major concern in most of the water bodies.

Seine nets (Fig. 6) are roughly rectangular in shape without a distinct bag and are set

vertically in water; to surround the school of fish generally pelagic. Shore seine is a large net operated near the bank of a river, reservoirs or beels. The net usually has two wings and a middle landing part. The net is payed in the form of an arc from the shore using a boat and a number of fishermen pulls the net from the shore. The foot rope of the net always touches the bottom and the net is pulled towards the shore and the fishes are collected from shore. Do-Dandi of Ganga river, Bori of Gujarat and Gorubale of Karnataka and Pattuvala or Chavittu vala of Kerala. Tana jaal, Ghayala jaal, Raja-rani jaal,Gheesa jaal, Ber jaal, Chati jaal, Ghon jaal, Moshori jaal, Fesi jaal, and Pet-kasi jaal operated in the north eastern regions are some shore seine nets of the country.

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Fig. 6 A. large beach seine in operation in Pulicat

Boat seines are also operated in inland water bodies. Its construction is similar to the bag

net and is operated from boats. The net is released from one or two boats to form an arc. After encircling the fish, the net is hauled from the boat. Buro jaal and Koni jaal are single boat seines operated in backwaters of West Bengal. Pesi jaal is another small boat seine. operated in Assam. Patua-jaal is a boat seine operated in Chilika lake for small clupeids and beloniforms.

Fig. 7. Boat seine operation in Chilika

Stow nets (Fig.) are conical bag nets operated in shallow waters and estuaries where tidal current is strong. The mouth of the net is kept open against the current by means of stakes driven into the bottom. Examples are Oonnivala operated in backwaters of Kerala, Behundi jaal of Hooghly estuary Gunja jaal operated in creeks of Kutch region of Gujarat and Gidasavala operated in Krishna and Godavari delta of Andhra Pradesh.

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Fig. 8. Oonnivala (stake net) in Kerala

Stow net is a bag net conical in shape similar to a trawl net. It is known by different names in different regions. The mouth of the net is fastened to the opposite river banks against the current using ropes or wire ropes. The upper edge of the net mouth is kept open with the help of bamboo poles fixed at both ends of the wing and near the mouth region of the net. The fishes are collected in the cod end as the current of water takes the fish inside the net. These nets are used only when there is sufficient flow of water. Baghjaal and Bion jaal of Assam are examples of stow nets.

Push nets (Fig.) are operated in shallow water bodies. It has a 'V' shaped bamboo frame to which the webbing is attached. The net is pushed through water by man wading and during operation it scraps the bottom. It is hauled at frequent intervals. Some scoop nets have a cod end to facilitate collection of catch. The net is also operated from boats. Pelni of Narmada, kamjaal and kursung jaal of Assam, Schiki of Hoogly and Kuppu valai of Tamil Nadu are some examples.

Stick held drag (Fig.) net is operated in Orissa, Madhya Pradesh, Andhra Pradesh and Kerala. Mesh size of the gear ranges from 10-15mm. Webbing is fixed to bamboo stick of 70cm to 90cm length at regular intervals to form a pouch. The net is dragged by two persons in shallow areas which are devoid of bottom obstruction. While hauling the net fishes are driven into the net from both sides by splashing water with one hand. A drag net thandevala with two poles on either side of the rectangular mouth are operated in backwaters of Kerala.

Scoop net or small bag nets (Fig. 20) with rectangular mouth or circular mouth with frame used to scoop fish out of water. Net is operated in beels, backwaters and other inland water bodies. Vadivala and koruvala of Kerala Bachra jaal and hatjaal of Assam are some examples Trawl fishing has been carried out on experimental basis in reservoirs and rivers. Otter trawling has been tried in Hoogly estuary, Hirakud reservoir, and in Gandhisagar reservoir. Operations of mini trawl in Kerala has been recommended as an active fishing method in reservoir for the control / capture / elimination of cat fishes, uneconomical fishes and trash fishes. It is not recommended in rivers.

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Fig. 9 Trawl operation using rope and anchor from a non-motorised canoe in Kariangode estuary, Kerala

Hand dredge Hand operated dredges (Fig. 10) (kuthi vaaral ) are used in backwaters in Kerala to harvest clams. The dredge is made of slightly inwardly curved horizontal plate of about 50 cm length having about 40 spikes pointing downward at the lower edge of the plate. To this curved plate an arch shaped bamboo frame of about 30 cm height at the center is attached. A small bag net of about 50 cm length is attached to this frame. The net and the dredge are attached to a wooden pole of approximately 10 m length. The dredges are operated by two or more fishermen using two canoes.

Fig. 10. Dredge operation for clams in Kariangode river

Lift net is a sheet of net, usually square, but may sometimes be conical, is stretched either by everal rods, ropes, or a frame. The fishing principle is to keep the net submerged for an interval of time and then pull it rapidly out of water so as to catch any fish, which happen to be over it. A variety of nets, employing the above principle of fishing, are operated in inland water bodies. A lure and lift net techniques is practiced in Tamil Nadu.

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Fig.11. Dipnet in Cochin backwater

Hand lift net operated along the shore in shallow waters. Four corners of the net are attached to poles tied at the center and is operated by dipping and quickly lifting the net out of water. Panjaal of Assam khora jai, kabjai and pah jaal are lift nets operated from boat or flat forms built in shallow waters of Brahmaputra. Kacha of Tamil Nadu, kurli of Punjab, arippuvala and hoop nets of Kerala, Maharashtra and Tamil Nadu and jamdajaal of Gujarat are examples.

Falling gear is usually a cone shaped net or other devices, which is dropped to cover aquatic animals and enclose them. Generally they are hand operated in shallow waters, but some are operated from a boat. The stick-held cast net is an example. The principle is to catch the fish by covering from above. The gear is cast over the area where the fish is available and the trapped fish are caught by hand. Cover pots, lantern net and plunge baskets are examples

Cast net (Fig.12) is found throughout India. Cast nets are conical bag shaped net. It is the most widely used gear in the inland sector by single fisherman. Three types of cast nets are operated in inland waters viz. with closing strings, with peripheral pockets and without strings, pockets and hauling rope. Iron sinkers are fixed in the lower periphery of the net. The net is thrown in a circular fashion over the water and due to the presence of sinkers the net sinks to the bottom. It is then hauled up with the help of the hauling rope tied to the apex of the net. Fishes that come within the area covered by the gears enter the pockets while hauling. The cast nets vary in their sizes. Based on the size and different mesh size, the nets are named differently. The cast nets are mostly made of PA multifilament. Khewali jaal of Assam, chakar jaal of Gujarat and veesuvala of Kerala are some examples of cast nets.

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Fig. 12. Operation of Polyamide monofilament shrimp cast net (stringed) from catamaram

in Pulicat lake

Gill nets (Fig. 13) are long walls of webbing hung vertically in water are either set in one spot or allowed to drift with the current (Fig. 27). Gill nets are used in rivers, reservoirs, beels and other inland water bodies. Gill nets can be operated in the bottom, midwater or surface targeting desired fish. These nets are also used as encircling gear. It is highly selective and can be used judiciously by using the optimum mesh size to capture the right size of the fish. Gill nets are also named by the target fish they capture. Gochail jaal of Allahabad, thangadi of Hoshangabad, kuto jaal of Hoogly, current jaal, langi jaal and phansi jaal of Assam and ozhuku vala of Kerala are examples. The rampant use of very thin polyamide monofilament materials, discarded and lost nets in the inland water bodies could lead to ghost fishing and can also cause environmental and ecological problems. Proper selection of mesh sizes, hanging ratio, and mode and time of operation can make gill net an eco-friendly, low energy and sustainable fishing method.

Fig.13. Gillnet fishermen from Kuppam river, Kerala

Traps (Fig. 14) are passive fishing gears into which the fish can enter voluntarily in such a manner that the entrance then becomes a non-return passage of the device. Trap fishing is highly fuel efficient both in terms of returns and biomass per unit of fuel consumed. Traps can fish continuously during day and night with periodical checking and the organisms can be retrieved alive without any damage. Traps are mostly made of bamboo, Palmyra fibres, coconut tree, coconut leaves etc. Kankada khadia and khonda screen traps in chilka lake, Orissa chempally koode of Kerala, kumini of Madhya Pradesh, sepa and dingora of Assam are some examples of fishing traps.

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Fig. 14. Traditional fish trap in Mogral river, Kerala

Fish barriers (Fig. 15) are long leaders of converging screens erected in shallow waters to lead the fishes into the chambers fixed in the end. Net barriers are slowly replacing the bamboo barriers as these are cost affective and saves labour and lasts longer than the bamboo screens. The gear consists of leaders, gathering ground, channels and filter platforms. The leaders guide the fish into the trap. The length varies from 10 to 50 m depending on the width of the river stream or canal. Water seep through the platform, leaving the fish. These gears are very effective in capturing nearly all fish moving downstream. The fish reaching inside the barriers are captured by using lift nets. Roak used in river Yamuna in Agra during summer to catch major carps, jano khonda or disco net of Chilka lake, banamara and betamara of northeastern states are some examples.

Fig.15. Fish barrier in Kozhikode district Hook and line fishing

Different lines such as hand line, pole and line, set line lone, drift line, long line, drop line, multiple baited lines, etc are also operated in inland waters. Some lines are operated without bait.

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Fig. 16 A. long line unit Purse net

It is a semicircular purse net extensively used in catching Hilsa (Fig. 17). The net consists of an elliptical frame by tying two-split bamboo on either side or a bag shaped net attached to it. The net with its mouth opened vertically is towed along the river bottom by 1 to 2 fishers while being steered by 2 more. The frame of the net consists of two long slender arched bamboo strips about 6 to 7 m long tied together at both the ends in the form of hinges. To this frame is attached a rounded bag shaped net having a mesh of 22 to 70 mm made of PA about 3 to 3.5 m deep. The mouth is kept open by a brick, iron ball or a stone weight of 1.5 to 4.0 kg tied to the center of the lower lip. There is a feeler cord fixed to the upper portion of the net to transmit the disturbance caused by the entrance of fish. The stout haul rope is paid out to the desired depth. This haul rope passes through a ring or Y-shaped piece of wood in the upper lip and attached to the middle of the lower lip immediately above the weight. Net is operated from a boat moving with the current. When any fish enters the net it causes certain jerk which is felt by the fisherman holding the rope, which immediately close the net by pulling the rope and haul the net. Illishashangala jaal' and karal shangala jaal are very popular purse nets in the lower Brahmaputra, the former for hilsa and the latter for migratory carps. This net is also seen in West Bengal.

Fig.17. Clap net in Hooghly

Brush parks are the most common fishing method employed in the beel (Fig.18). These parks mainly act as shelter areas. Two different types of brush parks locally known as katal / jeng and pit / chek, are erected in the beels of Assam. Katal fishing or katalmara is a method, which is extensively used in the beel fisheries of Assam. Katals are prepared by erecting tree branches in the bottom with a collection of water hyacinth, in the form of a circle. Pit / chek is a very large

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brush park (0.5 to 2.0 ha) erected in beels heavily infested with floating water hyacinth. Similar type of bush parks known as Phooms are seen in Loktak lake, Manipur. Fishes take shelter in this. During winter when the water level goes down, katal is surrounded using screen or net. Fishes are collected after removing the weeds

Fig.18. Bush park in a tributary of Kuppam river, Kerala

In the case of drive-in-nets (Fig. 19), the technique of this fishing method is to drive the fishes into fixed fishing gear from a distance. Sometimes gill nets are used for this purpose. The operation is done in the shallow areas. Scare lines can be made by inserting tender coconut leaves into the twists of a long coir rope or with broken pieces of bricks and thin strips of turtle shell similar to a stick held seine net. The net is fixed in the form of "U" and the fishes are driven into the net using the scare lines. In the final stage of operation of the net two ends are brought together and the confined fishes are captured. Beppevala in rivers of Kerala, gopal jaal in Allahabad, sone jaal and tik tiki khedani of Assam are examples.

Fig. 20. Drive-in-net

Above described are major fishing gears and methods of inland waters in India and there may be some other indigenous fishing methods in certain pockets, which is likely to be insignificant in terms of catch or employment. Major issues in the sector is given below.

• Habitat degradation due various anthropogenic activities • Siltation • Land reclamation • Profuse weed infestation • Aquatic pollution • Construction of check dams/barricades

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• Destruction of mangrove forest • Sand mining • Water abstraction in smaller water bodies • Invasive predators/exotic species • Large scale prawn seed collection from natural water bodies for farming • Destructive fishing methods • Bycatch/discards • Climate change

Towards Sustainable Fishery

Excess capacity and over exploitation is a major problem. Licensing of fishing craft and gear is required with periodic checking to control destructive fishing practices. Small meshed gears and use of mosquito net for fishing gear making should be banned. Gillnet with less than 90mm mesh size should not be used for hilsa fishing. Huge quantity of juveniles and post larvae are being landed in the stationary bag nets including juveniles of priced fishes like hilsa and pomfret. Such gears should be phased out or replaced with more selective gears. Buyback scheme can be introduced to purchase the licence of destructive gears. Completely ban the destructive fishing technique like blast fishing, electrical fishing and fishing using poison and chemicals. Trading of juvenile fishes need to be discouraged. Almost all gillnets are presently made of very thin nylon monofilament. Within 1-3 moths time the net get damaged and it is discarded as the fishermen usually does not mend the monofilament nets. The discarded non-biodegradable nets in the water bodies leads to ghost fishing.

CIFT has optimised mesh sizes for different gears based on the extensive field trials conducted in different water bodies and the recommendations have been communicated to the respective States for enacting. As the fisheries resources in open water bodies are common wealth, people utilising the same have the responsibly to conserve the same to prevent Tragedy of the commons proposed by British economist William Forster Lloyd. Responsible fishing practices using optimised fishing gears developed by CIFT should be adopted. It is believed that self-regulation by the fishermen and community managing the resources is better than master and slave approach for sustainable fishery

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Fisheries management measures for sustainable fishery in inland waters

1. Fishing capacity regulation/ license for craft and gear 2. Prevention of destructive fishing gears and practices 3. Mesh size regulation 4. MLS for inland fishes 5. Observing closed season and closed areas 6. Discouraging use of mosquito nets/ destructive fishing gears 7. Community pond/cages for fattening live juveniles of fishes landed in fishing gear 8. Species enhancement in selected water bodies 9. Prevent habitat degradation process 10. Banning of fish seed collection from natural waters 11. Stocking & ranching 12. Restoring connection between isolated ponds and open water bodies for facilitating

breeding migration 13. License for all aquaculture units to control the introduction of exotic predatory fish

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Engineering Tools and Technologies for Energy Efficient Fish Processing Operations

Manoj P. Samuel*, S. Murali, Aniesrani Delfiya D.S and Soumya Krishnan

Engineering Division, ICAR-Central Institute of Fisheries Technology, Kochi

*E-mail:[email protected]

Fisheries comprise a major economic activity within complex interactions between human beings and water - 'the first among equals' of the natural resources (Ahmed, 1992). Fisheries data assembled by the Food and Agriculture Organization (FAO) suggest that global marine fisheries catches increased to 86 million tonnes in 1996, then slightly declined. In the past three decades, employment in fisheries and aquaculture has grown at a higher rate than the growth of world population. The fishery engineering is evolving as an important domain in view of depleting stocks on both pre and post-harvest scenarios. It will also aid in fish processing technologies, optimizing energy and water use in seafood industries, mitigating climate change related issues and reducing carbon footprint. It is important to explore novel ways to obtain, quantify, and integrate industry responses to declining fishing stocks and increasing management regulations into fishery- and ecosystem-based management advice. The technological interventions help to reduce the wastage of fish, which is otherwise a highly perishable commodity by preservation technologies and converting it into value added products with higher shelf life. Use of appropriate technologies along the fish value chain will help in producing better quality products and fetch more markets and higher price.

Major areas of technological interventions in the field of fishery engineering cover design and

development of fish processing equipment and machineries, energy efficient and eco-friendly solar fish dryers, fuel efficient fishing vessels and fiberglass canoes, indigenous electronic instruments for application in harvest and post-harvest technology of fish, quality improvement of Indian fishing fleet and energy and water optimization techniques for fish processing industries. Focused areas include development of cost effective solar dryers with LPG, biomass, Infra-Red or electrical back-up heating systems, fish descaling machines, Fish freshness sensor etc. Technologies for fish processing and value addition Post-harvest processing of fish are important to reduce wastage, increase shelf-life, add more value to the products and ensure higher returns. The major engineering interventions for fish post-harvest operations, processing and value addition are given below: Solar dryers

30-40 % of fish caught is dried or processed for export and local consumption. Sun drying (open air drying) is the traditional method employed in most parts of the state to dry fishery products. It denotes the exposure of a commodity to direct solar radiation and the convective power of the natural wind. This form of energy is free, renewable and abundant in any part of the world especially in tropical countries. Also it offers a cheap method of drying but often results in

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inferior quality of product due to its dependence of weather conditions and vulnerability to the attack of dust, dirts, rains, insects, pests, and microorganisms. Solar drying is an alternative which offers numerous advantages over the traditional method and environmentally friendly and economically viable in the developing countries. In solar drying, a structure, often of very simple construction, is used to enhance the effect of the solar radiation. Compared to sun drying, solar dryers can generate higher air temperatures and consequential lower relative humidity, which are conducive to improved drying rates and lower final moisture content of the final products. However, there exist some problems associated with solar drying i.e. reliability of solar radiation during rainy period or cloudy days and its unavailability during night time. To overcome this limitation, an auxiliary heat source and forced convection system are recommended for assuring reliability and better control, respectively.

In a hybrid solar drying system, drying can be continued during off-sunshine hours by

utilizing backup heat source and stored heat energy of daytime sunshine. In this way, drying becomes continuous process and the product is saved from possible deterioration by microbial infestation. These types of Hybrid solar dryers find useful applications in developing countries where the conventional energy sources are either scarce or expensive and the heat generating capacity of the solar system alone is not sufficient. Further, to assist the drying process (forced convection) in a hybrid dryer, a small blower is attached in between solar collector and drying chamber or inside the drying chamber which is powered by solar PV panels installed on drying chamber. Moreover, power from PV panels can be used for street lighting purposes. In addition, if the proposed setup is not used for drying purpose (kept idle), then the same can be used to draw hot water for domestic use. Therefore, in a single set up, it is envisaged to have multiple utilities i.e. drying of fish, hot water and electricity generation.

Design of solar dryer varies from simple direct dryers to more complex hybrid designs.

Hybrid model solar dryers are having LPG, biogas, biomass or electricity as an alternate back up heating source for continuous hygienic drying of fish even under unfavourable weather conditions. ICAR-CIFT has developed different models and capacities of solar dryers for hygienic drying of fish. The capacity of these hybrid solar dryers varies from 6 to 110 m2 of tray spreading area for drying of various quantities of fish varying from 10 kg to 500 kg.

The labour requirement is considerably reduced compared to open sun drying in beaches /

coir mats because of the elimination of cleaning process due to sand and dust contamination. Re-handling process like spreading, sorting and storing because of non-drying or partial drying due to unfavourable weather conditions and spoilage due to rain is also not required. The drying time is reduced considerably with improved product quality. Improved shelf life and value addition of the product fetches higher income for the fisher folk. The eco-friendly solar drying system reduces fuel consumption and can have a significant impact on energy conservation.

ICAR-CIFT design includes small capacity dryers like solar tent dryers, natural convection

dryers etc. which will be useful to dry fish hygienically during sunny days. Solar tunnel dryers, solar fish dryers with alternate electrical back up (models: SDE-10, SDE-20 and SDE-50) and solar fish dryers with fire wood or biomass alternate back up heating system (models: SDF-20, SDF-50) etc. can be efficiently used to dry fish using renewable solar energy which is abundantly and freely available. The details of solar dryers with different backup systems are given below:

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Solar Dryer with LPG back-up

ICAR-CIFT designed and developed a novel system for drying of fish using solar energy supported by environment friendly LPG back up (Fig.1). In this dryer during sunny days fish will be dried using solar energy and when solar radiation is not sufficient during cloudy/ rainy days, LPG back up heating system will be automatically actuated to supplement the heat requirement. In the solar fish dryer with LPG back up heating system, water is heated with the help of solar vacuum tube collectors installed on the roof of the dryer and circulated through heat exchangers provided in the PUF insulated stainless steel drying chamber loaded with fish. Thus continuous drying is possible in this system without spoilage of the highly perishable commodity to obtain a good quality dried product.

This dryer is ideal for drying of fish, fruits, vegetables, spices and agro products without changing its colour and flavour. It helps to dry the products faster than open drying in the sun, by keeping the physico-chemical qualities like colour, taste and aroma of the dried food intact and with higher conservation of nutritional value. Programmable logic Controller (PLC) system can be incorporated for automatic control of temperature, humidity and drying time. Solar drying reduces fuel consumption and can have a significant impact on energy conservation.

Fig.1. ICAR-CIFT Solar-LPG Dryer

Solar dryer with Electrical back-up

Effective solar drying can be achieved by harnessing solar energy by specially designed solar air heating panels and proper circulation of the hot air across the SS trays loaded with fish (Fig.2). Food grade stainless steel is used for the fabrication of chamber and perforated trays which enable drying of fish in a hygienic manner. Since the drying chamber is closed, there is less chance of material spoilage by external factors. An alternate electrical back-up heating system under controlled temperature conditions enables the drying to continue even under unfavourable weather conditions like rain, cloud, non-sunny days and in night hours, so that the bacterial

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spoilage due to partial drying will not occur. Improved shelf life and value addition of the product fetches higher income for the fisher folk. The eco-friendly solar drying system reduces fuel consumption and can have a significant impact on energy conservation.

Fig. 2. ICAR-CIFT Solar-Electric Dryer

Solar-Biomass Hybrid dryer

A dryer working completely on renewable energy was designed and developed for eco- friendly operation. Solar Biomass Hybrid Dryer consists of well insulated and efficient solar air-heating panels, drying chamber, SS mesh trays, photo-voltaic cells, fans and biomass heating system (Fig.3). Hot air is generated by virtue of solar energy inside the heating panels and passed into the drying chamber. Continuous flow of hot air is maintained with the help of PhotoVoltaic cells and fans to enable drying process. During cloudy days when sufficient solar energy is not available to maintain required temperature within the dryer, an alternate biomass heating system is manually actuated. Thus a fully green technology for fish drying is achieved by this.

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Fig. 3. CIFT Solar-Biomass Dryer Solar Tunnel dryer

Solar tunnel dryer utilizes solar energy as the only source of heat for drying of the products. Heat absorbing area of 8 m2 is made of polycarbonate sheet (Fig. 4). Products to be dried are placed on nylon trays of dimension 0.8x0.4 m. The dimensions of the whole drying unit is 2.21x2.10x0.60 m. The capacity of the dryer is 5 kg. Drying takes place by convection of hot air within the drying chamber. Apart from fish, this dryer is also suitable for other agricultural products like fruits, vegetables and spices.

Fig. 4. ICAR-CIFT Solar-Tunnel Dryer

Solar Cabinet dryer with electrical back-up This offers a green technology supplemented by electrical back up in case of lacunae in solar radiation. The dryer consists of four drying chambers with nine trays in each chamber (Fig.5). The trays made of food grade stainless steel are stacked one over the other with a spacing of 10 cm. The perforated trays accomplish a through flow drying pattern within the dryer which enhances drying rates. Solar flat plate collectors with an area of 7 m2 transmit solar energy to the

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air flowing through the collector which is then directed to the drying chamber. The capacity of the dryer is 40 kg. Electrical back up comes into role once the desired temperature is not attained for the drying process, particularly during rainy or cloudy days.

Fig. 5. ICAR-CIFT Solar-Cabinet Dryer with Electrical back-up

Infrared drying

ICAR-CIFT has recently developed an Infra Red (IR) dryer heat transfer is happening by radiation between a hot element (infrared lamps) and a material (to be dried). Thermal radiation is considered to be infrared in the electromagnetic spectrum between the wavelength of 0.78 µm and 1000 µm. Infrared emitters offer efficient heat and much more advantages compared to other conventional heat technologies:

• No direct contact with the product High drying/heating rate • Infrared radiation can be focused where it is needed in a defined time, • Cost savings thanks to high overall efficiency and optimal infrared heaters lifetime.

Fish Descaling Machines

Fish descaling machine with variable drum speed

Fish descaling machine is designed and fabricated for removing the scales of fish easily.

This equipment can remove scales from almost all types/sizes/ species of fish ranging from marine to freshwater species like Sardine, Tilapia to Rohu. The machine is made of SS 304 and has 10 kg capacity. It contains a 1.5 hp induction motor and a Variable Frequency Drive (VFD) to vary the speed of the drum depending on the variety of the fish loaded. The drum is made of perforated SS 304 sheet fitted in a strong SS Frame. Water inlet facility is provided in the drum for easy removal of the scales from the drum so that area of contact to the surface will be more for removal of scales. The water outlet is also provided to remove scales and water from the machine. An Electronic RPM meter was attached with the descaling machine which directly displays the RPM of the drum. Speed of the drum is a factor influencing the efficiency. The machine takes only 3-5 minutes to clean 10 kg fish depending on the size.

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Fig. 6. Fish descaling machine with variable drum speed

Fish descaling machine with fixed drum speed- table top

Fish descaling machine is designed and fabricated for removing the scales of fish easily. This equipment can remove scales from almost all types/sizes/ species of fish ranging from marine to freshwater species like Sardine, Tilapia to Rohu. This machine is made of SS 304 and has 5 kg capacity. It contains a 0.5 HP AC motor with proper belt reduction mechanism to achieve required drum speed of 20-30 rpm. Body is fabricated in dismantling type one-inch square SS tube with a suitable covering in the electrical parts. The drum is made of perforated SS sheet fitted in a strong SS Frame having suitable projections to remove the scale and provided with a leak proof door with suitable lock.

Hand operated fish descaling machine

Fish descaling machine is designed and fabricated for removing the scales of fish easily. This

equipment can remove scales from almost all types/sizes/ species of fish ranging from marine to freshwater species like Sardine, Tilapia to Rohu (Fig.7). This machine is made of SS 304 and has 5 kg capacity. Body is fabricated in dismantling type 1 inch square SS tube. The drum of 255.5 mm diameter and 270 mm length is made of perforated SS sheet fitted in a strong SS Frame having suitable projections to remove the scale and provided with a leak proof door with suitable lock. A pedal is fitted in the side to rotate the drum manually.

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Fig. 7. Hand operated fish descaling machine

Fish meat bone separator

A Fish Meat Bone Separator with variable frequency drive (VFD) to separate pin bones from freshwater fish was designed and developed. This can be used at a range of 5-100 rpm. With a unique belt tighten system developed; the new machine can be easily adapted to any species and need not be customised for specimen during the design stage. In existing imported models, only two speeds are possible which restricts the yield efficiency in a single span operation and also limits easy switching of the system for utilising specimen other than for which the yield has been originally customised. The meat yield of this machine was about 60% against 35% in imported models. Capacity of the machine is 100kg/hour.

Modern hygienic mobile fish vending kiosk

Most of the fisher folk across India sell fish in an open basket without any hygienic

practices. The fish is kept in an open bag or container, it loses its freshness.They use ice purchased at high cost for temporary preservation and at the end of the day, if the fish is not sold, they give it at a low rate to customers with little or no profit. More over fish gets contaminated under unhygienic handling practices. The fish vending persons, especially women folk find it difficult to carry the fish as head load and subsequently sell it in the local markets or consumer doorsteps. In this context, the ICAR-CIFT have designed and developed a mobile fish vending kiosk for selling fish in the closed chilled chamber under hygienic conditions at consumer doorstep.

The major advantages of the new Kiosk are as follows:

● The mobile kiosk was designed considering the maximum weight that a man pulls on rickshaw.

● The mobile unit is mounted on frame with wheels at the bottom. The kiosk can carry 100kg fish with 20kg under chilled storage display in glass chamber and remaining in insulated ice box (developed by ICAR-CIFT).

● The main components of the kiosk are fish storage & display chilled glass chamber, hand operated descaling machine and fish dressing deck with wash basin, water tank, cutting tool, waste collection chamber and working space.

● The vending unit has been fabricated mainly using stainless steel (SS 304 Food Grade) and frame and supports are made with MS and GI sheets.

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● The kiosk main part i.e chilling unit & display for fish storage which was envisaged to power by solar energy through solar PV cells,however presently powered by AC current.

● The stored fish is covered with a transparent glass cover through which consumers can see the fish and select according to their choice of purchase.

● Kiosk is attached with hand operated descaling machine for removal of scales. The fish coming out of descaler is free of scales, dirt or slime.

● It also reduces human drudgery and avoids cross contamination, consumes less time. Fish dressing deck with wash basin is also designed conveniently to prepare fresh clean fish under hygienic conditions. Chilling of fish using electricity/PV cells or by adding large quantity of ice adds to cost to

the selling price. Since this technology has well insulated storage space for fish with provisions for refrigeration, it reduces the ice melting rate and its cost, thereby reducing the selling price. The unit also extends the storage quality of fish for 4- 5 days and increases marginal benefit to fish vendors.

It also helps change the practice of unhygienic handling and marketing of fish. Electronics and Instrumentation

ICAR-CIFT identified the vast scope of electronics and instrumentation for fisheries technological investigations and started research and development activities. This resulted in a series of instruments for systematic monitoring, analysis and assessment of the marine environment including the performance of the machinery used for harvesting the resources and post-harvest technology. Basic technologies developed in ICAR-CIFT include more than five dozens of electronic instruments with fully indigenous technology and more than 50 sensors with novel features and designs. The notable achievement is the development of indigenous sensors, which are rugged to withstand hostile marine environment and enable us to monitor field data from remote areas. The total instrumentation is built up around these sensors, with required electronics, new signal processors and other peripherals for solid-state data storing, compatibility to PC, wireless transmission to distant points etc.

Some of the instruments, which has got great attention and acceptance are as follows:

environmental data acquisition system, freezer temperature monitor, salinity temperature depth meter, hydro meteorological data acquisition system, warp load meter, solar radiation monitor and integrator, ship borne data acquisition system, water level recorder, ocean current meter, remote operated soil moisture meter, water activity meter, rheometer and micro algae concentration monitor. Since the instruments are designed to be compatible with computers and solid-state memory module, the information can be stored for long duration and retrieved at our convenience.

By effective use of efficient and appropriate engineering technologies which are cost-

effective, adaptable and environmentally friendly, the fishermen community as well as seafood industry can reduce the harvest and post-harvest expenses and losses, add more value to the products, ensure better fish value chain dynamics and thereby obtain more income. The use of green and clean technologies also ensures less carbon and water footprints.

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Commercialization and Agri-Business Incubation

Agri-Business Incubators (ABI) open new entry points in the agricultural value chains, which in turn can use to access new markets. They afford leverage through these entry points to accelerate agricultural development and offer the unique potential to develop small and medium-sized enterprises (SME’s) which can add value along these chains in ways which other development tools do not offer. There is no single “right way” to perform agribusiness incubation. Rather the work of agribusiness incubation depends on the state of development of the agribusiness ecosystem and changes over time as that ecosystem matures and develops. In its earliest phases, incubators demonstrate the viability of new business models and look to create and capture additional value from primary agricultural products. In underdeveloped agricultural economies, incubators help by strengthening and facilitating linkages between enterprises and new commercial opportunities. They open new windows on technologies appropriate to agribusiness enterprises and help agricultural enterprises discover new, potentially more competitive ways of doing business. In subsequent phases of development, incubators operate as network facilitators: they link specialized service providers to agribusinesses and link separate agribusinesses to one another. Finally, in a more advanced state of business development, incubators operate as conduits for the exchange of technology, products, inputs and management methods across national borders.

A more pragmatic system for business incubation and promoting start-up companies with

respect to agricultural technologies have been evolved in recent times within the ICAR-CIFT. The Agri-Business Incubation (ABI) center along with Institute Technology Management Unit (ITMU) seeks to provide business consulting services to agriculture-related businesses and helps to develop a strategic business plan. ABI facilitates for incubation of new business ideas based on new agricultural technologies by providing cheap space, facilities and required information and research inputs. The Agribusiness Incubator Program also seeks to provide business consulting services to agriculture-related businesses and helps to develop a strategic business plan.

The Engineering Division of ICAR-CIFT has commercialized its technologies like solar fish

dryers, fish descaling machines, refrigeration enabled fish vending machines etc through the ABI. On non-exclusive license mode, 10 firms have been empanelled to manufacture/fabricate machineries as per CIFT design and commercialize it to needed customers by paying royalty to the institute. In the financial year 2018-19 itself, 12 entrepreneurs have taken up solar fish drying technology and three start-ups came up by establishing CIFT designed fish vending kiosks. Five fish descaling machines were also successfully handed over to sea-food industries located both in Andhra Pradesh and Kerala. Apart from these, 10 numbers of fish dryers of 10 kg capacity were distributed among women SHG groups located in Kerala, Manipur and Assam for demonstration purposes. Furthermore, 28 incubatees (one physical and two virtual) have already registered under ABI in the current year for using engineering technologies. Apart from these, an MoU was signed between ICAR-CIFT and Society for Assistance to Fisherwomen (SAF), Directorate of Fisheries, Govt of Kerala, for fabrication and installation of 20 numbers of Refrigerated fish vending kiosk for the benefit of fisher women SHGs.

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Energy and water use optimization in seafood processing industry Energy consumption in seafood or any food processing plant depends largely upon the age

and scale of the plant, level of automation, intensity and type of processing operations, plant management practices, plant layout and organization, equipment efficiency and range of products manufactured. The cooking and canning are very energy-intensive processes, whereas the filleting consumes less energy. Thermal energy, in the form of steam and hot water, is used for cleaning, heating, sterilizing and for rendering. The operation of machinery, refrigeration, ventilation, lighting and production of compressed air uses high amount of electricity (Fig. 8). Similarly, seafood industry consumes significant amounts of water in each stage of processing (Fig.9). It also produces a large quantity of waste water. The CIFT have installed energy meters in three industries within Kochi cluster for monitoring the daily energy consumption pattern.

Fig. 8. Distribution of connected load in seafood processing units of the Kochi cluster (Source: BEE, 2015)

Fig. 9. Water use pattern in a typical seafood processing unit. (Source: BIM, 2017)

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Energy optimization methodologies

Energy optimization methodologies can be broadly classified in the following six categories:

Automation of existing process line Energy wastage in the seafood industry can be greatly reduced by precisely controlling the

working of all equipment in the process line. Merely by controlling the timely switching on and off equipment can save a lot of energy, which can be practically impossible in manual operation.

Sensitize the labor about energy conservation

The operation level labor’s attitude and behavior have a major impact on the energy optimization point of view. Awareness among the labors regarding energy wastage that can occur due to mere negligence or ignorance has to be created. Instructions can be given to them regarding reducing energy wastage, for example, the chill room doors should be closed immediately after loading or unloading to prevent temperature rise inside etc.

Equipment upgrade

Existing equipment should be monitored for their efficient working through periodic repair

and maintenance. Regular servicing and if required replacement of worn out parts should be done. This can actually improve the processing efficiency of the equipment and in turn of the whole plant. The usage of plate freezers considerably reduces the energy consumption in seafood freezing.

Replacement of out-dated equipment and technology

Latest technologies and sophisticated and energy saving equipment can be explored to reduce the energy consumption of plant. For example, reciprocating and centrifugal type compressors can be replaced by a screw compressor, which can give higher processing efficiency or Replacement of existing V-belt drive with synthetic energy efficient flat belt drive in the compressor motor. The direct contact water condensers can be replaced by Evapco type condensers. Installation of Variable Frequency Drive (VFD) for condenser water Pumps. These are relatively capital intensive method but high reduction in energy consumption can be obtained.

Energy auditing and budgeting

Effective reduction in energy consumption can be achieved through proper energy auditing

of the seafood industry. Energy audits can give an idea about the extent of energy utilized for various purposes in the industry and accordingly energy conservation measures can be executed. The energy auditing can be made easy through software like Energy Datamatrix which periodically check the energy consumption in seafood processing sectors.

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Use of renewable energy and green industry concept Switching to renewable energy sources from conventional sources are of great advantage not

only to the industry but also to the environment as a whole. Nowadays, the green industry is a trending concept which emphasizes on those activities and measures which help curb environmental depletion, swapping to renewable energy.

Water Optimization Methodologies

Substantial reduction in water consumption of a seafood processing industry can be brought about by adopting some of the below-mentioned methods.

Automation of equipment and process-line The extent of reduction in water consumption possible by automating the equipment cannot

be overlooked. Conventional taps may be replaced by self-closing ones. Cut-off valves, flow diversion valves etc. are dependable accessories which may be installed in the process-line to reduce water wastage. Sensor based solenoid valves may be fitted to the water supply system which can be operated automatically or by means of an Internet of Things (IoT) system. Monitoring water use pattern

Close monitoring of the industry's water use pattern can give a lot of insights. Sensors may be

installed in relevant points in the process-line for the same. This can be especially helpful in detecting any leaks by observing the sensor readings during the night. Even though this can incur some initial expenses to the industry, the savings both in terms of money and resources are exceptionally high. Many researchers have successfully developed system for online water monitoring based on different algorithms and tools like genetic Algorithm, Artificial neural networks, ZigBee, GPRS etc.(Liu et al, 2013; Yu et al., 2016). Recirculation and recycling

Considering the safety standards a seafood industry should maintain and there are some

constraints in adopting recycling of water in the process line. Nevertheless, opportunities for possible recirculation of water may be explored to reduce water consumption. Recirculated water can be used for employee wash rooms, Effluent Treatment Plant (ETP) operations and direct groundwater recharging. According to the literature, it is anticipated that a recycling unit in thawing equipment can reduce water consumption by 60 %.The different methods used for the treatment of wastewater in seafood industries are dissolved air floatation, dual media filter, activated carbon filter, sand filtration and tank stabilization, flash mixer, clariflocculator, secondary clarifiers and sludge drying beds, etc. Coarse material and settleable solids are removed during primary treatments by screening, grit removal and sedimentation. Updating or modifying conventional systems

Minor changes may be incorporated into the existing system to utilize the available

resources smartly. For example, trigger action shut off devices or nozzles can be fitted onto the

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hose, the addition of timers or pedals to ensure water, adjusting the flow to the minimum required to maintain performance etc. This can be relative very cheap in investment but can tremendously improve the cleaning potential of water since it is pressurized during application. Almost 40% reduction in water usage can be attained by this method. References/suggested reading Ahmed, M., D. Capistrano and M. Hossain. (1992) Redirecting benefits to genuine fishers: Bangladesh's new

fisheries management policy. Naga: The ICLARM Quarterly, October 1992. pp 31-34

Bureau of Energy Efficiency (BEE) (2015) Manual on Energy Conservation Opportunities in Seafood Processing industries in Kochi: New Delhi

BIM (2017) Ireland’s seafood development agency, Resource Efficiency Guide for Seafood Processors: BIM, Irish

FAO (2014) The State of World Fisheries and Aquaculture- Opportunities and challenges.Food and Agriculture Organization of the United Nations Rome. 2014

Liu. S., Tai, H., Ding, Q., Li, D., Xu, L., and Wei, Y. (2013)A hybrid approach of support vector regression with genetic algorithm optimization for aquaculture water quality prediction. Mathematical and Computer Modelling. 58(3): 458 – 465

Yu, H., Chen, Y., Hassan, S., and Li, D. (2016). Dissolved oxygen content prediction in crab culture using a hybrid intelligent method. Sci. Rep. 6: 27-292

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Policies and Regulations for Marine Fisheries Conservation and Management in India

K. Sunil Mohamed

Central Marine Fisheries Research Institute (CMFRI), PO Box 1603, Kochi 682018 E-mail:[email protected]

Policy Overview

India’s marine fisheries development has been guided in the past by the five-year plans and by the policy documents of 1994, 2004 and 2017 brought out by the erstwhile Department of Animal Husbandry, Dairying and Fisheries (DADF), Ministry of Agriculture and Farmers' Welfare, Government of India. As a renewable natural resource, fish harvests need to be ecologically and economically sustainable to ensure equity and livelihood security to fishers. Numbering nearly 40 lakhs, fishers and allied workers are one of the economically weaker sections of the society and their well-being and economic development is of paramount importance to the country. In order to uplift this section of the society, meet the food security and also to ensure sustainable harvests of fishery resources, comprehensive policies are necessary.

The 2017 policy (National Policy on Marine Fisheries, NPMF) was for the first time published as a gazette notification and it was also for the first time based on a nation-wide stakeholder survey. The 2017 NPMF is guided by the public trust doctrine which states that the State as a trustee is under a legal duty to protect the natural resources and these resources meant for public use cannot be converted into private ownership. The policy strategy is based on the following 4 pillars:

1. sustainable development, 2. principle of subsidiarity, 3. inter-generational equity, 4. precautionary approach.

The policy had a vision statement which stated - “A healthy and vibrant marine fisheries

sector that meets the needs of the present and future generations”. There were 62 policy statements which covered Fisheries management, Monitoring, Control and Surveillance, Marine environment and pollution, Post-harvest and processing, Trade, Mariculture, Fisher welfare, social security nets and institutional credits, Gender equality, Island fisheries, Climate change adaptation and new initiatives, Regional cooperation, International agreements/ arrangements and Governance and institutional aspects. This policy is expected to guide the development of marine fisheries in the country for the next 10 years.

Governance of marine fisheries

As per the Constitution of India, division of subjects, fisheries in the territorial waters (up to 12 nm from the coast) is regulated by the maritime states. The zone from 12 to 200 nm or the EEZ of India is regulated by the Union Government. All the maritime states of India have promulgated marine fisheries regulation acts (MFRAs), and these laws are used by the State

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Department of Fisheries to regulate and manage their fisheries. The Union Government is in the process of developing a law for the 12-200 nm zone. The draft bill which is in circulation is called the National Marine Fisheries Regulation and Management Bill 2019. Besides these primary laws, there are a number of laws which in many ways exercise control over the fishing (see Figure below).

Regulations in marine fisheries

As stated earlier the maritime states manage and regulate their fisheries through their

MFRAs. Fisheries management is basically done through input or output control. The input and output control measures normally used in India are shown in Table below:

These regulations have been amended by different states from time to time. The Government of Kerala has recently amended the KMFRA to bring in the following regulations:

Regulation on fishing methods Limits on net sizes and net mesh sizes Cap on engine HP / use of VMS for mechanized vessels Regulation on minimum legal size of fish (MLS)

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Zonation of fishing grounds Regulations on closed season Regulation on fishing effort Regulations on co-management of fishery resources

Destructive fishing practices have a devastating effect on fish stocks and on the marine

environment. An example is pair trawling or bull trawling. The CMFRI estimates that the efficiency of pair trawling is 3 to 4 times more as compared to conventional trawling, leading to rapid depletion of resources and conflicts with seine fishermen who target pelagic resources. Therefore, this type of fishing practice is not to be permitted.

Fishing based on Fish Aggregating Device (FAD) is in vogue along the west coast. Scientific studies by CMFRI have proved that such a practice results in recruitment overfishing reducing the spawning stock to one-fifth of the mean value and significant decrease in catch and catch rates of cuttlefish.

Minimum Legal Size (MLS) was introduced for the first time in the country in Kerala to control excessive capture of juvenile fish leading to growth overfishing. In Kerala during 2017, the loss due to catch below MLS was estimated as Rs. 500 crores. In 2018, initial estimates indicate that it is one fourth of 2017, indicating good enforcement by DOF. The CMFRI has recommended MLS for different maritime states as given in table below:

CMFRI has studied the issue of overcapacity of fishing fleets on an all India basis and

revealed that there is considerable amount of overcapitalization in the fishing fleets. The overcapacity is highly variable in different states and varies from a high 430% in mechanized sector to a low 18% in motorized sector. In order to control this the state has introduced moratorium on new fishing crafts for next 10 years, registration of boat building yards and only replacement of existing crafts will be allowed.

Another major improvement is the introduction of participatory management or co-management by amending the KMFRA in 2017. Fishers are empowered to become active members of the fisheries management council, balancing rights and responsibilities, and working in partnership, rather than antagonistically, with government. The law allows for a consultative type of co-management where mechanisms exist for government to consult with fishers but all

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decisions are taken by government. There are now 222 village councils, 9 district councils and 1 apex state council. The TORs of these councils have been finalized. Such a co-management system has been recommended at the national level also as shown in figure below.

Infographic of the proposed council-based fisheries management for India (adapted from Mohamed et al., 2017). Triangle apices shows the top of hierarchy within the system.

The Indian Marine Fisheries Code (IMFC) advises adopting a participatory or co-management approach for the entire country (Mohamed et al., 2017) by creating fisheries management councils with adequate representation for fishers and other stakeholders. In this bottom-up tiered system the consensus decisions taken in the lower councils with scientific support are ratified by the upper councils, finally enabling equitable decisions and rulemaking. The National Marine Fisheries Management Council (NMFMC) will be the apex council under the Union Ministry of Fisheries which will have oversight of all councils. In a maritime state, the Village FMC is at the lowest rung, which reports to the District FMC which in turn reports to the State FMC.

References/suggested reading Rohit, Prathibha and Dineshbabu, A P and Sasikumar, Geetha and Swathi Lekshmi, P S and Mini, K G and

Vivekanandan, E and Thomas, Sujitha and Rajesh, K M and Purushottama, G B and Sulochanan, Bindu and Viswambharan, Divya and Kini, Sharath (2016) Marine Fisheries Policy Series-5; Management Plans for the Marine Fisheries of Karnataka. Marine Fisheries Policy Series - 5. pp. 1-110. ISSN 2394-8019

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Mohamed, K S and Malayilethu, Vinod and Suseelan, Ranjith (2018) Developments in progressing India's marine fisheries towards Marine Stewardship Council (MSC) certification. Marine Fisheries Information Service; Technical and Extension Series (235). pp. 1-12. ISSN 0254-380 X

Mohamed, K S and Sathianandan, T V and Zacharia, P U (2017) Brief results of the national stakeholder survey leading to National Policy on Marine Fisheries - 2017. Marine Fisheries Information Service; Technical and Extension Series (234). pp. 3-10. ISSN 0254-380 X

Mohamed, K S (2016) Marine Fisheries Policy Brief-4; Fishing Using Lights How should India handle this new development. Marine Fisheries Policy Brief - 4, 4. pp: 1-8

Ramachandran, C and Mohamed, K S (2015) Responsible Fisheries Kerala Fish Workers Open New Path in Co-Governance. Economic and Political Weekly, 50 (35). pp: 16-18

Mohamed, K S and Zacharia, P U and Maheswarudu, G and Sathianandan, T V and Abdussamad, E M and Ganga, U and Pillai, S Lakshmi and Sobhana, K S and Nair, Rekha J and Josileen, Jose and Chakraborty, Rekha D and Kizhakudan, Shoba Joe and Najmudeen, T M (2014) Minimum Legal Size (MLS) of capture to avoid growth overfishing of commercially exploited fish and shellfish species of Kerala. Marine Fisheries Information Service; Technical and Extension Series (220). pp: 3-7

Mohamed, K S and Vijayakumaran, K and Zacharia, P U and Sathianandan, T V and Maheswarudu, G and Kripa, V and Narayanakumar, R and Rohit, Prathibha and Joshi, K K and Sankar, T V and Edwin, Leela and Ashok Kumar, K and Bindu, J and Gopal, Nikita and Pravin, P (2017) CMFRI Marine Fisheries Policy Series No-4; Indian Marine Fisheries Code: Guidance on a Marine Fisheries Management Model for India. CMFRI Marine Fisheries Policy Series (4). ICAR - Central Marine Fisheries Research Institute, Kochi. p:. 1-102

Sasikumar, Geetha and Mohamed, K S and Rohit, Prathibha and SampathKumar, G (2015) CMFRI Marine Fisheries Policy Series No.1; Policy guidance on cuttlefish fishery using Fish Aggregating Devices. Marine Fisheries Policy Series (1). Central Marine Fisheries Research Institute. pp. 1-56

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Marine Electronic Equipments used in Fishing Vessels C.D.Joshy

Central Institute of Fisheries Nautical and Engineering Training, Kochi-16


There are different electronic equipments used onboard fishing vessels for various purposes. This may be classified into four main groups. Navigational equipments, Communication equipments, Fish finding equipments and Emergency Equipments.

Navigational Equipments Global Positioning System (GPS)

The equipment GPS, Global Positioning System, is used generally for position finding. Many countries are developing their own GPS systems and some are operational and some are under construction and will be available in the near future The American system is more precisely called Navstar GPS, standing for Navigation Satellite Timing And Ranging Global Positioning System. The Russian system named ‘Glonass’ stands for Global Navigation Satellite System. These are space-based systems, utilizing orbiting satellites to transmit their signals. Navstar and Glonass, are unique in their features of high accuracy and high availability, providing position information every second, twenty-four hours a day, three hundred and sixty five days a year. Modern GPSs with differential mode of operation (DGPS), accuracies of under a meter or even in centimeters are possible, even on a moving vehicle.

Other systems Other satellite navigation systems in use or various states of development include:

• Beidou — China's regional system that China has proposed to expand into a global system.

• Galileo — a proposed global system being developed by the European Union, joined by China, Israel, India, Morocco, Saudi Arabia and South Korea, Ukraine planned to be operational by 2010.

• GLONASS — Russia's global system which is being restored to full availability in partnership with India.

Communication VHF, HF,MF INMARSAT

Fish Finding ECHO SOUNDER NET SOUNDER

SONAR

Life Saving SART EPIRB

Marine Electronic Equipments

Navigational G.P.S A.I.S

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• Indian Regional Navigational Satellite System (IRNSS) — India's proposed regional system.

G.P.S (NAVSTAR)

The NAVSTAR GPS is currently the only fully functional Global Navigation Satellite System (GNSS). More than two dozen GPS satellites are in medium Earth orbit, transmitting signals allowing GPS receivers to determine the receiver's location, speed and direction.GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.

The current GPS consists of three major segments. These are the space segment (SS), a control segment (CS), and a user segment (US). Space segment

The space segment (SS) is composed of the orbiting GPS satellites. More than 30 GPS satellites are distributed in six circular orbital planes centered on the Earth. Orbiting at an altitude of approximately 20,200 kilometers (12,600 miles or 10,900 nautical or 14,400 NM)), each satellite makes two complete orbits in one day, so it passes over the same location on Earth once each day. The orbits are arranged so that at least six satellites are always within line of sight from almost anywhere on Earth.

Control segment

The flight paths of the satellites are tracked by US Air Force monitoring stations in Hawaii, Kwajalein, Ascension Island, Diego Garcia, and Colorado Springs, along with monitor stations The master control station contacts each GPS satellite regularly with a navigational update (using the ground antennas at Ascension Island, Diego Garcia, Kwajalein, and Colorado Springs).

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User segment The user's GPS receiver is the user segment (US) of the GPS system. In general, GPS receivers are composed of an antenna, tuned to the frequencies transmitted by the satellites, receiver-processors, and a highly-stable clock. They may also include a display for providing location and speed information to the user. A receiver is often described by its number of channels: this signifies how many satellites it can monitor simultaneously, typically have between twelve and twenty channels.

The user's GPS receiver is the user segment (US) of the GPS system. In general, GPS

receivers are composed of an antenna, tuned to the frequencies transmitted by the satellites, receiver-processors, and a highly-stable clock. They may also include a display for providing location and speed information to the user. A receiver is often described by its number of channels: this signifies how many satellites it can monitor simultaneously, typically have between twelve and twenty channels.

Working

GPS satellites broadcast three different types of data in the primary navigation signal. The first is the almanac which sends coarse time information along with status information about the satellites. The second is the ephemeris, which contains orbital information that allows the receiver to calculate the position of the satellite.

The satellites also broadcast two forms of clock information, the Coarse / Acquisition

code, or C/A which is freely available to the public, and the restricted Precise code, or P-code, usually reserved for military applications. Each satellite sends a distinct C/A code, which allows it to be uniquely identified. In normal operation, the P code is first encrypted into the Y-code, or P(Y), which can only be decrypted by units with a valid decryption key. Frequencies used by GPS include:

Calculating positions

A GPS receiver calculates its position by measuring the distance between it’s antenna and three or more GPS satellites. Measuring the time delay between transmission and reception of each GPS radio signal gives the distance to each satellite, since the signal travels at a known speed. The signals also carry information about the satellites' location. By determining the position of, and distance to, at least three satellites, the receiver can compute its position using trilateration. Receivers typically do not have perfectly accurate clocks and therefore track one or more additional satellites to correct the receiver's clock error.

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The coordinates are calculated according to the World Geodetic System WGS84 coordinate system. To calculate its position, a receiver needs to know the precise time. The satellites are equipped with extremely accurate atomic clocks, and the receiver uses an internal crystal oscillator-based clock that is continually updated using the signals from the satellites.

The receiver identifies each satellite's signal by its distinct C/A code pattern, then

measures the time delay for each satellite. To do this, the receiver produces an identical C/A sequence using the same seed number as the satellite. By lining up the two sequences, the receiver can measure the delay and calculate the distance to the satellite, called the pseudo range. The orbital position data from the Navigation Message is then used to calculate the satellite's precise position. Knowing the position and the distance of a satellite indicates that the receiver is located somewhere on the surface of an imaginary sphere centered on that satellite and whose radius is the distance to it. When four satellites are measured simultaneously, the intersection of the four imaginary spheres reveals the location of the receiver. Earth-based users can substitute the sphere of the planet for one satellite by using their altitude. Often, these spheres will overlap slightly instead of meeting at one point, so the receiver will yield a mathematically most-probable position (and often indicate the uncertainty).

Accuracy and error sources

The position calculated by a GPS receiver requires the current time, the position of the satellite and the measured delay of the received signal. The position accuracy is primarily dependent on the satellite position and signal delay.

Changing atmospheric conditions change the speed of the GPS signals as they pass through the Earth's atmosphere and ionosphere. These effects are minimized when the satellite is directly overhead, and become greater for satellites nearer the horizon, since the signal is affected for a longer time.

Humidity also causes a variable delay, resulting in errors similar to ionospheric delay, but

occurring in the troposphere. This effect is both more localized and changes quicker than the ionospheric effects, and is not frequency dependent. These traits making precise measurement and compensation of humidity errors more difficult than for ionospheric effects.

GPS signals can also be affected by multipath issues, where the radio signals reflect off

surrounding terrain; buildings, canyon walls, hard ground, etc. These delayed signals can cause inaccuracy.

Techniques to improve accuracy - Augmentation

Augmentation methods of improving accuracy rely on external information being integrated into the calculation process. There are many such systems in place and they are generally named or described based on how the GPS sensor receives the information. Some systems transmit additional information about sources of error (such as clock drift, ephemeris, or ionospheric delay), others provide direct measurements of how much the signal was off in the past, while a third group provide additional navigational or vehicle information to be integrated in the calculation process.

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Examples of augmentation systems include the Wide Area Augmentation System,

Differential GPS, and Inertial Navigation Systems. DGPS (Differential Global Positioning System)

Differential GPS works by having a reference system at a known location measure the

errors in the signals and send corrections to users in the "local" area. These corrections will not be universal, but will be useful over a significant area. The

corrections are normally sent every few seconds. The user is generally some mobile platform such as a ship, car, truck or even an aircraft. WAAS (Wide Area Augmentation System)

WAAS consists of approximately 25 ground reference stations positioned across the United States that monitor GPS satellite data. Two master stations, located on either coast, collect data from the reference stations and create a GPS correction message. This correction accounts for GPS satellite orbit and clock drift plus signal delays caused by the atmosphere and ionosphere. The corrected differential message is then broadcast through one of two geostationary satellites, or satellites with a fixed position over the equator. The information is compatible with the basic GPS signal structure, which means any WAAS-enabled GPS receiver can read the signal.

GPS in Marine Navigation

Position

The GPS will receive signals from satellites in space, compute position on the earth's surface, and display it as a pair of coordinates. There are different types of position coordinates used for different purposes. Time

The basic time used for navigation is called UTC, for Universal Time, Coordinated. The GPS displays UTC, which is updated every second. The maximum error is one half second, as long as at least one satellite is being received. The GPS also displays local time in a 24-hour form. Waypoints

A waypoint is a storage area for the coordinates of a place that you come from or go to. Waypoints can be referred to by number or by name. The number of way points that can be stored in the GPS depends on its memory capacity. Waypoint zero (0) is a special waypoint, because the GPS computer automatically stores its present location into waypoint zero each time it is told to navigate to a different place. Since waypoint zero is the place you're starting from, it is automatically given the name "START".

When a waypoint is been selected for navigation, the GPS will give all information

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required for navigation; like course to the waypoint, distance to the waypoint, SOG, VMG, time to reach, ETA etc. Speed and Course

The GPS receiver measures the speed and course over the ground of the receiving antenna. This measurement is generally accurate to about 0.5 knots (0.1 knots, when used with a differential data receiver) and responds to changes in speed within a few seconds.

Navigation

Navigation display will show position and steering information. Most of the GPS are having Course Deviation Indicator, or CDI. This is a graphic indication of Cross Track Error, or the distance you are from the desired course line, with a maximum reading of +/0.32 nautical miles.

The display tells you to steer right or left of the desired course line.

Alarms The GPS features several different alarms to assist you in navigation:

• Destination Alarm The destination alarm alerts the user when they have reached the destination waypoint. When a rout is active, the alarm will sound when the final destination has been reached.

• Cross Track Error Alarm The Cross Track Error Alarm alerts you when you are off course.

• Anchor Watch alarm The Anchor Watch alarm alerts you when your boat has drifted beyond a specified distance from the position where the alarm was enabled.

• Hazard Alarm (Danger zone alarm) The Hazard Alarm alerts you when your boat is near a hazardous waypoint. Waypoints are classified as hazardous in the waypoint library when the hazard type is assigned.

ECHO SOUNDER & FISH FINDER

Echo sounder is used to measure the depth of sea. Later after modifications, this was used to locate fish shoals and got the name Fish Finder.

ADVANTAGES OF ULTRASONIC SOUND in fish finding:

• Because of its high frequency, ultrasonic sound will be reflected better by small objects, such as fish, than with the audible sound.

• Under water noises are normally caused by the rush of water, pounding of engines or the propeller and are well within the range of audible sound. If audible sound is used, its echo will be mixed with the other noises and the extraction of its echo will be difficult. If ultrasonic sound is used, filtering of its echo from other noises will be easy.

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• Loss of sound energy due to dispersion can be minimised by focusing the sound into a beam. To concentrate audible sound of 1000 c/s in water, with a wavelength of 1.5 m, the radiating surface should have a diameter of at least 1.5 m. But for a 30 k c/s sound pulse the minimum radiating surface required is only 5cms. This can easily be constructed.

Absorption of ultrasonic sound

The rate of absorption increases greatly with higher frequencies. An ultrasonic sound

pulse is absorbed more in the water than audible sound and therefore, not reaches as far as audible sound. This is an important disadvantage. This can be minimised by means of high transmission power, good receiving amplification and the concentration of sound. Principle of echo-sounding

Sound propagates at constant velocity in a particular medium independent of frequency and intensity of sound. The velocity of sound can be used to measure distance. By measuring the time between the generation of a sound pulse and the arrival of it’s echo, then multiplying it by the known velocity of sound and dividing the result by two will be the distance.

Distance = Velocity X Time / 2. For example, if this time interval is one second, then

distance will be 1500 x 1/2 = 750 m.

Ultrasonic sound is utilised in fish finder and Echo sounder. Sound pulse is emitted into the water in definite sequence by a pulse generator via a transducer. The pulsed wave goes in the water at an approximate velocity of 1500 m/s and reflects at any objects located in the path. A fraction of the pulse (echo) will reach back to the former position, is picked up by the same transducer, is amplified and indicated by a combined timing and indicating unit.

Block diagram of an echosounder

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Transmitter

The transmitter generates an electrical pulse at a particular frequency for which the

transducer is designed. A command from the pulse trigger contact in the recording unit tells the pulse former when to function. A gate or switching pulse is produced in the pulse former which determines the length or duration of the pulse. The pulse which is generated by the oscillator is then amplified in the power amplifier before it is fed to the transducer. Transducer

The primary function of the transducer is to transform electrical energy into sound energy when sound is to be emitted and conversely, to convert the sound energy into electrical energy when echoes are received. An additional function of the transducer is to concentrate the sound energy which is emitted into a beam.

There are two main types of transducers. One based on the principle of Magneto-striction and other Electro-striction.

Receiver

The weak electrical signals produced in the transducer when echoes are received will be amplified several thousand times before being passed on to the recorder. This amplification takes place in the receiver and the amount of amplification can be varied by the sensitivity control. In order to reduce or remove the echoes from very close range, which are much stronger than those from a distance, the sensitivity of the receiver is automatically suppressed so that it is low at the moment of transmission but increases with time, to full sensitivity. This type of depth (or rather distance) adjusted amplification is known as Time Varied Gain (TVG).

Recorder

Olden type of Fish finder has paper recorder. Picture will be formed in paper like fax paper. Nowadays fish finders have video display – CRT or LCD type.

Main controls of an echo sounder ON OFF: Normally the ON-OFF switch is part of the GAIN CONTROL knob. This is to turn ON or OFF the power of the echo-sounder.

GAIN: It is like Volume control of a transistor radio. If you increase the GAIN, the returning echo will be louder and the stylus makes darker marks, but with high gain there will be noise (unwanted signals) and the stylus also makes marks for noise which appears like grains. Proper adjust of the gain knob is required to get a clear picture. DEPTH RANGE: Depth range is the layer or thickness of the column of water that you can see on your echo-sounder picture. Normally there are two knobs for adjusting range. First one is for the BASIC DEPTH RANGE, which selects the maximum working depth starting from the surface of the transducer. Second knob is for PHASING RANGES, that is, for lowering the selected layer of the water-column a few meters down. Surface mark will not be visible since it starts from a few meters down from the surface.

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PULSE: The length of the pulse can be adjusted using the PULSE knob. Short pulse gives more pixels and fish discrimination will be better. But the power of the pulse will be less. This is because before reaching the transmitter to its full power, the pulse has to emit (short time). Generally, short pulse is used for shallow water and long pulse for deep water.

White Line: This control differentiates an echo sounder from fish finder. This control is useful in attempting to distinguish traces of fish school close to the sea bottom. Generally, when the fish are close to the bottom, the two traces will merge and the fish trace will be indistinguishable from that of the bottom. The application of white line control creates a two-layer bottom marking. Hard objects such as rocks, wrecks are marked in both the layer; whereas soft objects such as school of fish, marked only on the upper layer. This feature helps to identify the school of fish close to the sea bottom. PAPER SPEED: Speed of the echo sounder paper moving from one roll to the other can be adjusted with this control. The shape of an echo picture may be stretched or compressed depending on the paper speed. With a slow paper speed, you can see more details. Controls of Video Sounders

• Brightness/ Brilliance control: used to increase or decrease the intensity of the picture.

• Image advance speed control: similar to paper speed control, this can be used to increase or decrease the image advancing speed. Some sounders are having a facility of auto speed control which when activated; the image speed will be adjusted automatically with respect to the speed of the boat and the range selection.

• Range Selection: Basic depth can be selected either starting from zero or from a different starting point. Phasing range is possible in any order or by the use of VRM (Variable Ranger Marker). Auto range facility is available, in which the selection of range will be automatically done by the machine according to the depth of the sea.

• Alarms: Different alarms can be set as per the requirement. Fish alarm helps to get alert

when fish traces are formed at a particular depth, which helps in midwater-trawling. Shallow water alarm will give alert when the boat is approaching to a region where the depth is less. Deep water alarm helps to prevent the boat from going to deep waters.

• Colour selection: There are different colour presentations and the required colours can

be selected as per user’s choice. Here the colour denotes the echo strength.

• Frequency Selection: Dual frequency operation is common. One high frequency and one low frequency are used. Both pictures can be viewed simultaneously in the same screen by dividing the screen into two halves.

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Advantage of High frequency Advantage of Low frequency Better resolution, better discrimination Less absorption, thus more range Narrow beam width, thus less shadow area

Wide beam width thus more coverage

Used in shallow waters Used in deep waters

A-scope: helps to see the picture of exactly under your transducer. Zoom: helps to see the picture enlarged and with more details. Bottom Lock: this is used at the time of bottom trawling. A predefined column of water above the bottom can be viewed separately. This gives more details of the bottom.

SONAR

The word SONAR is derived from `SOund Navigation And Ranging'. Sonar is a type of Echo sounder capable of transmitting and receiving in more or less horizontal direction.

To get longer range, Lower frequencies are used in Sonar since they travel farther in water. Common sonar frequencies range from 10 to 25 kHz. The power output is increased up to 10kW as compared with about 1kW for an average echo-sounder. To get such high power into the water, the pulse length is increased up to 40ms. The transmission is more or less horizontal; the transducer can be moved in azimuth and lateral axis. All sonar have manual tilt and training control for the transducers. Most sonar are able to train the transducer through 360 degree in azimuth and to indicate its position by means of a pointer on the console. Similar controls and an indicator are provided for the angle of tilt.

The weak signals that are returned from fish school, etc. to the transducer are amplified by the receiver to a sufficient magnitude to mark a paper chart, operate a CRT and produce the audible indication from a loudspeaker.

Block diagram of the main components of a sonar

installation

A display which is better able to indicate distance and direction is the plan position indication (PPI) on a CRT, which is similar to a very slow radar. If a target is detected, the echo is shown on the screen, giving an indication of its range and bearing. A paper recorder may be combined with a CRT for closer study. The audible indication of the echoes by loudspeaker is quite essential for the identification of various targets. An experienced operator can distinguish between different types of echoes better by the sound than from a paper recorder or CRT display.

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Net sounder (Netsonde)

The net sounder is an aid for trawl fishing. For a successful fishing, the knowledge of the position and state of the trawl information contribute widely. This requires necessary sensors / transducers be located on the net, and the indicator / receiver installed on board the ship along with the link medium either by cable or through radio means. The transducers give inputs regarding trawl opening both horizontal and vertical, Vertical depths from the trawl to seabed and sea surface, water temperature, catch details etc. This information has been connected to the receiver through a link medium. The receiver may include alphanumeric display to indicate various parameters on selection of the same through a control panel.

"Trawl eye" sensor Marine radio communication

For marine communication, Terrestrial and Satellite communications are used. Generally MF, HF, VHF bands are used for Terrestrial communications and UHF band is used for Satellite communications. The frequency spectrum is given below:

Frequency Band Frequency Range Wavelength

Medium frequency

High frequency

Very high frequency

Ultra High frequency

MF

HF

VHF

UHF

300 KHz to 3 MHz

3 MHz to 30 MHz

30 MHz to 300 MHz

300 MHz to 3 GHz

1km to 100m

100m to 10m

10m to 1m

1m to 10cm

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VHF radiotelephone

For short distance communication (30 to 40NM) a VHF radio telephone is used. It consists of a Transmitter and a Receiver in one single unit (commonly known as Transceiver). The frequency band of this equipment is 156 to 174 MHz and is divided into various international marine channels. For example, Channel-16 is used for calling purpose and its frequency is 156.80 MHz.

VHF communication is Line of Sight communication; hence the antenna height is a factor for good reception and transmission. Care must be taken to fix the antenna as high as possible.

Automatic Identification System (AIS)

The Automatic Identification System (AIS) is used for identification and locating vessels. AIS provides a means for ships to electronically exchange ship data including: identification, position, course, and speed, with other nearby ships. This information can be displayed on a screen. AIS is intended to assist the vessel's watch keeping officers and allow maritime authorities to track and monitor vessel movements. It works by integrating with VHF, GPS and Gyrocompass.

AIS is a mandatory equipment to be fitted aboard international voyaging ships with gross tonnage (GRT) of 300 or more and all passenger ships regardless of size. It is estimated that more than 40,000 ships currently carry AIS class A equipment.

AIS transponders automatically broadcast information, such as their position, speed, and

navigational status, at regular intervals via a VHF transmitter built into the transponder. The information originates from the ship's navigational sensors, typically its GPS receiver and gyrocompass. Other information, such as the vessel name and call sign, is programmed when installing the equipment and is also transmitted regularly. The signals are received by AIS transponders fitted on other ships or on land based systems. The received information can be displayed on a screen or chart plotter, showing the positions of other vessels in much the same manner as a radar display.

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Broadcast information

AIS broadcasts three types of information, namely Static Data, Dynamic Data and Voyage related data.

Static Data:

• MMSI (Maritime Mobile Service Identity) • IMO number (Where available) • Call sign & name • Length and beam • Vessel Type • Location of position-fixing antenna on the ship • Update rate: 6 min.

Dynamic Data • Ship’s position • Course over ground (COG) • Speed over ground (SOG) • Heading • Navigation status (manual input) • Rate of turn--ROT (where available) • Update rates dependent on speed and course alternation. ( 2 sec –3 min)

Voyage related Data: • Ship’s Draft • Hazardous cargo (type) • Destination and ETA (at masters discretion) • Route plan (Optional) • Update rate: 6 min. • Short safety-related messages • User-selectable • Update rate: as required

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