HULL FOULING AS A MECHANISM FOR MARINE INVASIVE

SPECIES INTRODUCTIONS

PROCEEDINGS OF A WORKSHOP ON CURRENT ISSUES AND POTENTIAL MANAGEMENT STRATEGIES FEBRUARY 12-13 2003

June 2005

COVERCommercial vessel in a Honolulu drydock showing a typical level of fouling and a close-

up of the fouling community showing the invasive bryozoan Schizoporella errata.Photos by L.S. Godwin

HULL FOULING AS A MECHANISM FOR MARINE INVASIVE SPECIES INTRODUCTIONS

L. S. Godwin, Editor

The proceedings of a workshop on current issues and potential management strategies conducted February 12-13 2004 in Honolulu, Hawaii

Hawaii Coral Reef Initiative –Research Program

Bernice Pauahi Bishop Museum

Hawaii Biological Survey

TABLE OF CONTENTS

Preface — Godwin, L. S.

Maritime Activities as a Mechanism for Introducing Marine Alien Species: Issues and Management

— Godwin, L. S. ………………………………………………………………………………………………1

Factors that Influence Hull Fouling on Ocean-going Vessels — Floerl, O. …………………………………...…6

Bio-fouling on Merchant Vessels in New Zealand — A.D.M.Coutts & M.D. Taylor………………………….14

Potential for the Introduction and Spread of Marine Pests by Private Yachts

— O. Floerl & G. Inglis……………………………………………………………………………………...22

Slow-moving Barge Introduces Biosecurity Risk to the Marlborough Sounds, New Zealand

— A.D.M. Coutts…. ………………………………………………………………………………………..29

Managing Marine Biosecurity in New Zealand — A.D.M. Coutts………………………………………………..37

Current Research in Marine Biosecurity Undertaken by the National Institute of Water and Atmospheric Research,

New Zealand

— O. Floerl, G. Inglis, N. Gust, B. Hayden, I. Fitridge & G.Fenwick……………………………………………43

Development of an Initial Framework for the Management of Hull Fouling as a Marine AIS Transport Mechanism

— L. S. Godwin…………………………………………………………………………………………………………..48

PrefaceMaritime vessel activity acting a mechanism for the transport of marine AIS is a complex issue involving more than just ballast water. Ocean-going vessels can be thought of as biological islands for species that dwell in harbors and estuaries around the world. These vessels provide substrate for the settlement of species associated with fouling communities, protected recesses that can be occupied by both sessile and mobile fauna, and enclosed spaces that hold water in which everything from plankton to fish can become entrained. The vectors associated with ocean-going vessels are ballast water, sediments, and hull fouling, and should be thought of as a collective unit.

The editor of this volume (Godwin) began collaborative efforts with the State of Ha waii Department of Land and Natural Resources, Division of Aquatic Resources (DLNR-DAR) to form the Alien Aquatic Organism Task Force (AAOTF) in 2003. This task force was made up of stakeholders from the public and private sector and was tasked to develop a framework for the management of ballast water, ballast sediments and hull fouling. The task force was successfully formed and began meeting in October 2002.The efforts by the AAOTF were integrated with the creation of an overall aquatic alien species management plan for the State of Hawaii, which was begun by the DLNR-DAR and The Nature Conservancy of Hawaii in 2003.

A workshop was conducted February 12 and 13, 2003 focusing on hull fouling as a mechanism for alien species transport and potential management strategies. This was accomplished with two invited speakers from New Zealand.

Dr. Oliver Floerl, Marine Biosecurity Researcher, National Institute of Water and Atmospheric Research

Ashley Coutts, Marine Biosecurity Division, Cawthron Institute

This workshop presented current research and knowledge concerning hull fouling introductions and began a process of developing a framework for potential management strategies. The goal of this process was the development of information that can be integrated into the overall alien aquatic species management plan through specific efforts concentrating on mechanisms associated with maritime vessel activity. The papers in this volume are a product of this workshop.

The first paper by Godwin is an introduction to the issue of aquatic invasive species transport by maritime vessel activity. A final paper by Godwin summarizes the efforts to develop an information framework for management strategies for minimizing aquatic alien species introductions through hull fouling.

A comprehensive paper on the factors influencing the development of hull fouling on maritime vessels is presented by Floerl. The Floerl and Inglis paper specifically focuses on the hull fouling of private yachts as an aquatic invasive species transport mechanism. Floerl et al. provide an overview of current research activities undertaken by the National Institute of Water and Atmospheric Research in New Zealand, which deal with aquatic invasive species.

Coutts and Taylor provide a paper that covers the issue of hull fouling transport of aquatic invasive species by merchant vessels in New Zealand. Coutts is the sole author on a paper that documents the introduction and spread of a tunicate species in New Zealand that is associated with hull fouling community. Another paper by Coutts presents a researchers perspective on efforts to minimize aquatic invasive species by resource management agencies.

This volume was made possible by funding by the Hawaii Coral Reef Initiative Research Program (Grant #Z616358) and collaborative efforts with DLNR-DAR and Dale Hazelhurst at Matson Navigation in Hawaii. Many thanks are extended to the Mike Hamnett, Kristine Davidson, and Risa Minato at the Hawaii Coral Reef Initiative Research Program for their support of this project, as well as providing additional funding for the printing costs of this proceedings.

L.S.G

Honolulu, Hawaii, July, 2005

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Hull Fouling as a Mechanism for Marine Invasive Species Introductions.Proceedings of a Workshop on Current Issues and Potential Management Strategies February 12-13 2004. Honolulu, Hawaii . Edited by L.S. Godwin.

Maritime Activities as a Mechanism for Introducing Marine Alien Species:Issues and Management

L. SCOTT GODWIN

Hawai ´i Biological Survey, B. P. Bishop Museum, 1525 Bernice St., Honolulu, Hawai ´i 96817 USA. Email: sgodwin@bishopmuseum.org

Abstract

Maritime vessel activity acting a mechanism for the transport of marine aquatic invasive species (AIS) is a complex issue involving more than just ballast water. Ocean-going vessels can be thought of as biological islands for species that dwell in harbors and estuaries around the world. These vessels provide substrate for the settlement of species associated with fouling communities, protected recesses that can be occupied by both sessile and mobile fauna, and enclosed spaces that hold water in which everything from plankton to fish can become entrained. The vectors associated with ocean-going vessels are ballast water, sediments, and hull fouling, and should be thought of as a collective unit.

IntroductionBiological invasions brought about by anthropogenic influences have occurred throughout the world through a variety of mechanisms including maritime shipping, live seafood and bait shipments, aquaculture, shipments of commercial and institutional aquarium species, and the activities of education and research institutions. The primary pathway identified for marine aquatic invasive species (AIS) introductions has been ma ritime vessel traffic to ports around the world through ballast water discharge (Williams et al., 1988; Carlton & Geller, 1993; Ruiz et al., 2000a). Although this pathway is blamed for the majority of marine AIS introductions around the United States, the amountof ballast water being released varies among ports (Carlton et al., 1995; Smith et al., 1996, Godwin & Eldredge, 2001). There are other pathways associated with maritime vessel activity that can be responsible for introductions.

Maritime vessel activity acting a mechanism for the transport of marine AIS is a complex issue involving more than just ballast water. Ocean-going vessels can be thought of as biological islands for species that dwell in harbors and estuaries around the world. These vessels provide substrate for the settlement of species associated with fouling communities, protected recesses that can be occupied by both sessile and mobile fauna, and enclosed spaces that hold water in which everything from plankton to fish can become entrained (Wonham et al., 2000). The vectors associated with ocean-going vessels are ballast water, sediments, and hull fouling, and should be thought of as a collective unit.

Maritime Vessel Vectors for AIS

Ballast Water

From the early history of seafaring to the present, ocean-going vessels have needed ballast. All vessels before the middle of the 19th century used solid ballast in the form of sand, rocks, and other heavy materials. As ships became larger it became necessary to design ballast systems with dedicated tanks that could be filled with water. The need to use the aquatic environment for a transportation medium in the growing global economy has lead to the increases in vessel size and ballast water volume. This increased ballast water volume combined with faster ship speeds allows the uptake and survival of an increased number of organisms.

Organisms that are associated with marine plankton communities can be pulled into the ballast tanks of vessels during ballasting operations. These organisms are characterized as holoplankton, meroplankton, and tychoplankton. The holoplankton are species that live entirely in the water column their entire life. Holoplankton are further divided into the phytoplankton, which includes unicellular algae and various bacteria, and the zooplankton. This latter grouping includes small crustaceans, gelatinous species and a variety of other organisms. Meroplankton are the larval forms of marine species that use the water column to feed and disperse before becoming adult organisms. The larvae and eggs of crabs, barnacles, snails, clams, starfish, worms, fish and many other species are present in meroplankton and represent a large part of the biomass of plankton communities. Tychoplankton are

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species that normally live in bottom commu nities and become suspended in the water column temporarily. Additionally, adult organisms of animals such as fish and crabs can become entrained in ballast tanks by being in close proximity to seachest intakes or as attached organisms on debris.

Bacteria that have the potential for causing human health problems can also be found in ballast water. In the early 1990s shellfish beds in the southeastern United Sates along the Gulf of Mexico had to be closed because of the presence of cholera bacteria (Vibrio cholerae). This occurrence of Vibrio cholerae was traced back to ballast water discharges from vessels arriving from South America. The strain present in the Gulf of Mexico was the same that triggered an epidemic in South America that caused 10,000 deaths. The vibrios are waterborne bacteria that cause cholera when humans ingest contaminated water or raw or poorly cooked seafood taken from contaminated areas. There are 139 serogroups of Vibrio cholerae but only two - (01 and 0139) - cause cholera of epidemic proportions. The association of cholera bacteria with ballast water began to be realized more widely following the study of McCarthy & Khambaty (1994) in the Gulf of Mexico. Further research has detected both 01 and 0139 serogroups in ballast water being discharged in the United States Mid-Atlantic ports of Baltimore and Norfolk in the Chesapeake Bay (Ruiz et al., 2000b).

Sediments

Vessels generally ballast in coastal areas or ports that have a great deal of particulate matter suspended in the water column. This suspended matter is made up of organic and inorganic detritus and plankton. Particles begin to settle and form a sediment layer after ballast water is pumped into tanks. These layers can be up to eight centimeters thick (Godwin, personal observation) and can provide a habitat for benthic fauna. A portion of the sediments can become re-suspended and discharged during ballasting and deballasting operations. Ballast tanks will always retain water and sediments in unpumpable sections of the tank until it is re -suspended by ballasting operations or movement of the vessel during transit. This material is removed from the tank periodically to prevent damage to pumps, and is conducted by members of the crew during port visits and sea transits or by shipyard workers during service periods. In both cases the material can be either intentionally or unintentionally dumped overboard.

These ballast water sediments can harbor communities of adult organisms that result from the settlement of larvae and eggs from the meroplankton. These organisms can mature and become a source for new larvae that become suspended within the water column of the ballast tank. Another common component of the sediment is the resting stages of phytoplankton species such as dinoflagellates and diatoms. Only a few of the studies listed have dealt with ballast sediments. The most notable are the studies by Hallegraeff et al. (1990) and Hallegraeff & Bolch (1992) and Kelly et al. (1999) that demonstrated the presence of viable resting stages of phytoplankton species in ballast sediments. These studies connected the introduction of the toxic dinoflagellates that are transported as cysts to ballast sediments. In the first two studies, the toxic dinoflagellates Gymnodinium catenatum and Alexandrium

catenella, which cause paralytic shellfish poisoning, were identified from ballast sediments sampled from commercial cargo vessels arriving to Southern Australia. These sediments can also harbor bacterial communities that can flourish by deriving nutrients from the abundant organic matter settling out to the bottom of the ballast tank.

There are sediment accumulations associated with maritime vessel activity that are not due to ballast water operations. A source common to any type of vessel is the sediment found on anchors and anchor chains, which can accumulate in the chain locker compartment. These areas of the vessel can provide a sheltered habitat for a variety of animals that are adapted to an intertidal existence along coastlines and others that can exist in an encysted stage, such as the microalgae mentioned earlier. Vessels that conduct unique operations such as dredging and those that function as work platforms (i.e., barges, floating drydocks) have to be considered as well. These vessels can transport sediments through its accumulation on deck surfaces and on gear associated with their unique operations. Very little has been done to survey this type of sediment transport due to the random nature of these arrivals to port systems.

Hull Fouling

Ballast water is the pathway that has been the major focus of investigation as a marine invasion vector, and the biofouling that occurs on the surfaces of vessel hulls has been given less attention. Historically, wooden sailing ships provided an ideal surface to which marine fouling organisms could attach. Common fouling organisms on these vessels were the wood-boring shipworms (Teredo sp.). The cosmopolitan range of this organism is thought to have resulted from worldwide spread by wooden vessels, especially as trade routes opened up between the Atlantic and the Pacific. Hull fouling has been dramatically reduced with the advent of steel hulls and anti-fouling coatings. The steps taken by large ocean going vessels and personal craft to eliminate hull fouling are not completely effective though, and organisms are still being transported by this means.

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The organisms that generally foul vessel hulls are the typical species found in natural marine intertidal and subtidal sessile invertebrate communities. The typical invertebrate organisms associated with marine fouling communities are arthropods (barnacles, amphipods, and crabs), molluscs (mussels, clams, and sea slugs), sponges, bryozoans (moss animals), cnidarians (hydroids and anemones), protozoans, annelids (marine worms), and chordates (sea squirts and fish), as well as macroalgae (seaweed). If these fouling communities become very developed they can also provide microhabitats for mobile organisms such as fish. Initial settlement of fouling organisms tends to be in sheltered areas of the hull, such as sea chest intakes and rudder posts, and develop in areas where anti-fouling coatings have been compromised (Ranier, 1995, Coutts, 1999, James & Hayden, 2000, Godwin, 2003, Godwin et al., 2004). Anti-fouling coatings wear off along the bilge keel and weld seams, and are inadequately applied in some cases, all which make the surfaces susceptible to settlement by fouling organisms. Further work has focused on the transport of hull fouling organisms on personal craft throughout the tropical Pacific (Floerl & Inglis, 2001).

Minimizing Effects Through Management in the U.S.A.In the aquatic environment it is considered unrealistic to be able to eradicate an AIS once it has become established. The best strategy is to minimize the likelihood of initial introduction through prevention and outreach efforts. The most common approach for prevention is to target individual species that are potentially invasive to an area. This is a method proven to be effective in terrestrial systems, however, a more comprehensive approach in aquatic environments is to identify major pathways that can expose habitats to AIS and determine ways to control their potential effects. There are many pathways that can transport AIS to aquatic systems and a variety of management tools and treatment options aimed at prevention. This section briefly covers efforts aimed at prevention of AIS introductions associated with maritime vessels.

Due to the impacts documented by the invasion of the zebra mussel to the Great Lakes, Congress passed the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 (NANPCA). The NANPCA legislation created mandatory ballast water management guidelines that applied only to the Great Lakes. A reauthorization of NANPCA in 1996 created the National Invasive Species Act of 1996 (NISA), which expanded the legislation to cover all U.S. ports. Under NISA, the U.S. Coast Guard (USCG) developed voluntary ballast water management guidelines and mandatory ballast water management reporting and record keeping. NISA required the USCG to submit a report to Congress to evaluate the effectiveness of the voluntary ballast water management program. This report was submitted in June 2002 and concluded that compliance was too low to allow for an accurate assessment and proposed regulations that would make the voluntary guidelines mandatory. The proposed mandatory guidelines would require all vessels equipped with ballast water tanks entering U.S. waters after operating beyond the Exclusive Economic Zone (EEZ) to use one of the following approaches:

♦ Complete exchange of ballast water intended for discharge in U.S. waters. This exchange must take place no less than 200 nautical miles from any shore.

♦ Retain ballast water on board the vessel

♦ Prior to entry into U.S waters, use an environmentally sound ballast water management method that has been approved by the USCG

♦ Discharge ballast water to an approved reception facility.

In conjunction with this proposed rulemaking there are other aspects that are in development that involve the setting of standards and an approval process for experimental technologies for the purpose of ballast water treatment. This approval process will be designed to encourage vessel owners to participate with the experimental process of developing effective technologies for ballast water treatment. Also in development will be penalty provisions that will be attached to the new legislation. A public comment phase for this effort began in January 2003 and is scheduled to proceed until October 2003.

Presently, the NISA 1996 legislation is being reauthorized as the National Aquatic Invasive Species Act 2003 (NAISA). This is expanded legislation (still pending at the time of this writing) that seeks to provide tools and coordination to manage AIS threats more broadly. The NAISA legislation will implement a framework for an effective AIS management program. The components of this framework will be coordinated between all levels of government in partnership with private sector stakeholders. The components of the framework are:

♦ Prevention – Increased efforts focused on ballast water, sediments and hull fouling of maritime vessels arriving from outside the EEZ and domestic coastwise traffic inside the EEZ. Pursuit of environmentally sound treatment and prevention methods for all high risk pathways.

♦ Public Outreach and Education – Provisions to provide support for education and outreach to states, industry and tribes that focus on high risk pathways and measures to minimize introduction and spread of AIS.

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♦ Early Detection and Response – Coordination with state, local and tribal governments to establish monitoring and rapid response program for AIS.

♦ Research and Risk Analysis – research to determine predictive guidelines for AIS introduction and establishment and risk assessment activities to develop management strategies to minimize introductions.

♦ Control and Management – Strategies directed towards management guidelines for AIS that have become established.

DiscussionAwareness of the marine AIS issue and its connection to maritime shipping activities, both domestic and international, will be an important component in the future efforts in protecting the marine environment in the face of a growing global economy. Outreach to the public sector areas tasked with the management of aquatic resources and private sector interests that conduct operations with the potential for transporting AIS is a required component for success. Collaborative efforts between multiple stakeholder groups will continue to be the basis for effective and useful tools to minimize the impact of AIS. The mindset of industry and government concerning AIS transport by maritime vessel activity must become broader and recognize that the issue is more complex than just regulating ballast water. It will take awareness by both sectors to achieve the maximum positive effect for the environment, while minimizing the impact to the maritime industry.

AcknowledgementsThe information in this paper has been gained from years of collaboration with individuals in the maritime industry, United States Coast Guard, and fellow researchers in the field of marine AIS. Helpful comments were provided by J.T. Carlton and L.G. Eldredge.

Literature CitedApte, S., B.S. Holland, L.S. Godwin, & J.P.A. Gardner. 2000. Jumping ship: a stepping stone event mediating

transfer of nonindigenous species via a potentially unsuitable environment. Biological Invasions 2: 75-79.Carlton, J.T. & J.B. Geller.1993. Ecological roulette: Biological invasions and the global transport of non-

indigenous marine organisms. Science 261: 78-82._ _ _, D. Reid & H. van Leeuwen. 1995. The Role of Shipping in the Introduction of Nonindigenous Aquatic

Organisms to the Coastal Waters of the United States (other than the Great Lakes) and the Analysis of

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Cohen, A. N. & J. T. Carlton. 1995. Biological Study. Nonindigenous Aquatic Species in a United States Estuary:

A Case Study of the Biological Invasions of the San Francisco Bay and Delta. U. S. Fish and Wildlife Service, Washington, D. C. and the National Sea Grant College Program, Connecticut Sea Grant, NTIS No. PB96-166525.

Coutts, A.D.M. 1999. Hull fouling as a modern vector for marine biological invasions: investigation of merchant

vessels visiting northern Tasmania. M.S. Thesis. Faculty of Fisheries and Marine Environment, Australian Maritime College.

Floerl, O. & G.J. Inglis. 2001. Human influences on the contagion of nonindigenous marine species in boat harbors. Proceedings of the International Conference on Marine Bioinvasions, New Orleans, April 9-11

2001.Godwin, L.S. & L.G. Eldredge. 2001. The South Oahu Marine Invasion Shipping Study (SOMISS). Final report

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_ _ _,, L.G. Eldredge & K. Gaut. 2004. Hull fouling as a mechanism for the introduction and dispersal of marine

alien species to the main Hawaiian Islands. Bishop Museum Tech. Report #XXHallegraeff, G. M., C. J. Bolch, J. Bryan & B. Koerbin. 1990. Microalgal spores in ship’s ballast water: A danger

to aquaculture. In E. Graneli, B. Sundstrom, L. Edler and D. M. Anderson (eds.) Toxic Marine

Phytoplankton, pp. 475-480. International Conference on Toxic Marine Phytoplankton, Lund, Sweden._ _ _, & C. J. Bolch. 1992. Transport of diatom and dinoflagellate resting spores in ship’s ballast water:

Implications for plankton biogeography and aquaculture. Journal of Plankton Research 14(8):1067-1084

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James, P. & B. Hayden. 2000. The potential for the introduction of exotic species by vessel hull fouling: a

preliminary study . NIWA Client report No.WLG 00/51. NIWA Wellington, NZ.Kelly, J. M. 1999. Ballast water and sediments as a mechanism for unwanted species introductions into Washington

State. Journal of Shellfish Research 12(2): 405-410.McCarthy, S. A. & F. M. Khambaty. 1994. International dissemination of epidemic Vibrio cholerae by cargo ship

ballast and other non-potable waters. Applied Environmental Microbiology 60(7): 2597-2601.Nalepa, T. F. & D. W. Schloesser (eds). 1992. Zebra Mussels: Biology, Impacts, and Control. Lewis Publishers,

Inc. (CRC Press), Boca Raton, FL., pp. 677-697.Ranier, S. F. 1995. Potential for the Introduction and Translocation of Exotic Species by Hull Fouling: A

Preliminary Assessment. Centre for Research on Introduced Marine Pests Technical Report No. 1. Hobart, Tasmania.

Ruiz, G. M., P. W. Fofonoff, J. T. Carlton, M. J. Wonham & A. H. Hines. 2000a. Invasion of coastal marine communities in North America: apparent patterns, processes and biases. Annual Review of Ecology and

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microorganisms by ships. Nature 408: 49Smith, L. D., M. J. Wonham, L. D. McCann, D. M. Reid, J. T. Carlton, & G. M. Ruiz. 1996. Shipping Study II:

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Wonham, M.J., J.T. Carlton, G.M. Ruiz & L.D. Smith. 2000. Fish and ships: relating dispersal frequency to success in biological invasions. Marine Biology 136: 1111-112

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Hull Fouling as a Mechanism for Marine Invasive Species Introductions.Proceedings of a Workshop on Current Issues and Potential Management Strategies

February 12-13 2003. Honolulu, Hawaii . Edited by L.S. Godwin.

Factors that influence hull fouling on ocean-going vessels

OLIVER FLOERL

National Centre of Marine Biodiversity and Biosecurity, National Institute of Water and Atmospheric Research, P.O. Box 8602,

Christchurch, New Zealand. Email: O.Floerl@niwa.co.nz

Abstract

Ship hull fouling is amongst the most important vectors for the introduction and spread of non -indigenous marine species. To prevent or limit the transport of sessile organisms on vessel hulls it is important to understand the factors that determine their settlement and recruitment to these surfaces. In this paper I outline how factors associated with (i) characteristics of ships, (ii) characteristics of source ports, and (iii) the biology and physiology of fouling organisms influence the abundance of marine fouling on the hulls of ocea n-going vessels.

Introduction

Hull fouling - the growth of marine organisms on the bottom of ships and boats - is a nuisance to humans that dates back as far as the beginning of seamanship. The presence of organisms on submerged parts of ship hulls causes a considerable increase in friction of the hull and results in a loss in speed and/or increase in fuel consumption of the vessel (Christie & Dalley, 1987; AMOG Consulting, 2002). Movements of fouled vessels between distant ports can also facilitate the transport of marine biota to regions outside their natural ranges. Recent biological surveys and literature studies suggest that in many locales – including Hawaii, New Zealand and Australia - the majority of established exotic marine species are likely to have arrived on vessel hulls (Cranfield et al., 1998; Hewitt et al., 1999; Eldredge & Carlton, 2002).

Significant progress in the development of toxic antifouling paints over the past few decades has caused a tendency to dismiss the disproportionate contribution of hull fouling as a result of historical introductions, rather than acknowledge it as a contemporary process. However, recent work from New Zealand suggests that, despite the considerable improvements in antifouling paint performance, approximately the same number of exotic fouling species became established in New Zealand between 1958 and 1998 as during the first half of the 1900s (Cranfield et al., 1998). Furthermore, recent surveys of merchant vessels in Australia (Coutts, 1999), Germany (Gollasch et al., 1995; Gollasch & Riemann-Zuerneck, 1996; Faubel & Gollasch, 1996; Gollasch, 1999) , Hawaii (Godwin & Eldredge, 2001) and New Zealand (Hay & Dodgshun, 1997; James & Hayden, 2000) have all recorded extensive fouling assemblages that contained a large number of non-indigenous species, and some recent introductions have been directly related to hull fouling (Thresher, 1999; Field, 1999; DeFelice & Godwin, 1999; Apte et al., 2000). These and other studies (see AMOG Consulting, 2002) were carried out long after effective antifouling paints had become the principal means to protect ship hulls from marine growth. Clearly, the levels of fouling carried by modern vessels are only a fraction of that transported during the times of wooden and unprotected vessel hulls (Carlton, 1992; Carlton, 1999) . However, because of financial pressure on shipping companies and, possibly, lax behaviour in some cases, vessel hulls still become fouled. Hull fouling remains an important, but largely unrecognised and/or neglected vector for the introduction and spread of non-indigenous marine plants and invertebrates.

In the following sections the topic of ship hulls as diverse habitats for marine sessile organisms is introduced, and a brief summary of the factors that influence the amount of marine fouling on vessel hulls is covered. These can be broadly grouped into three categories: (i)characteristics of ships, (ii) characteristics of source ports, and (iii) characteristics of fouling organisms. Management actions that control one or several of these factors could achieve a reduction in the amount of fouling on ship hulls and, therefore, a reduction in transfers of marine non-indigenous species to locations outside their native range.

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Ship hulls – diverse habitats for sessile marine organisms

Ocean-going vessels come in many types (e.g. tankers, bulk carriers, fishing trawlers, military vessels, and sailing or motor yachts) and vary in the shape and size of their hulls (Schormann et al., 1990). The submerged parts of vessel hulls usually float several metres away from the seafloor and the wharves and/or pontoons to which they moor. Marine sessile organisms reach prospective settlement sites most commonly during their planktonic phase as larvae or spores (Grahame & Branch, 1985; Santelices, 1990). Competent propagules of many sessile species require particular habitats for settlement and growth (Meadows & Campbell, 1972; Pawlik, 1992). The structural diversity of vessel hulls provides a range of habitats suitable for a large variety of marine sessile animals and plants. For example, the angle of available settlement surfaces on vessel hulls ranges from vertical (near the waterline and on the keel if one is present) to horizontal (underside of hull). Similarly, the exposure to sunlight across a ship hull ranges from full exposure to completely shaded (Fig. 1a). When a vessel is moving, frontal parts of the hull, in particula r the area around the bow, are subject to a large amount of drag caused by water moving across the hull surface. In contrast, there are areas near the stern of most vessels – inparticular those associated with rudder recesses or propeller shafts – where d rag is low or negligible (hydrodynamic protection) (Coutts, 1999; Fig. 1b). This also applies to sea-chests, which are recesses built into the hulls of large ships and through which ballast water is taken up for stabilisation (Dodgshun & Coutts, 2002).Ship hulls provide a suitable habitat for thousands of marine sessile and even motile species (Woods Hole Oceanographic Institution, 1952).

Factors that influence fouling on ship hulls

Research into methods of keeping hulls free of fouling biota commenced many centuries ago (a historical account is given in Woods Hole Oceanographic Institution, 1952). So far, an effective ‘silver bullet’ for prevention of fouling has not been found (as indicated by an ongoing series of International Congresses on Marine Fouling and Co rrosion). As is discussed below, the amount of fouling on hulls depends on a multitude of factors that are associated with the ships themselves, with the environments they are frequently moored in, and with biological traits of the organisms involved.

Fi gure 1. Habitat diversity of ship hulls. Gradients in A, surface angle, exposure to sunlight, and B, drag along and across vessel hulls.

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(i) Characteristics of ships and hull maintenance practices

During centuries of research into hull fouling prevention the incorporation of toxic substances into a paint matrix emerged as the most common and successful method, and today, toxic “antifouling paints” are virtually the only way in which owners and operators of commercial and recreational vessel protect their hulls from accumulating marine growth. The way in which antifouling paints interact with settling larvae varies between taxa and antifouling agents and commonly involves pre - or post-attachment mortality of the larvae, or repellent effects (Crisp & Austin, 1960; Wisely, 1962; Wisely, 1963a; Wisely, 1963b; Wisely, 1964). Early paint formulae, such as soluble matrix and contact leaching systems, worked well when combined with copper, zinc, arsenic or tin, but failed to prevent fouling for longer than two years (Christie & Dalley, 1987; Callow, 1990) . Self-polishingcopolymer paints based on the organotin compound tributyl-tin (TBT), were first developed in the late 1950s (Montermoso et al., 1958) , and launched on the market in the early 1970s. With service lives of up to five years they represented a revolutionary event in the history of maritime technology (Banfield, 1980; Christie & Dalley, 1987; Callow, 1990). Unfortunately, the resulting high levels of TBT in seawater and coastal marine sediments were found to have deleterious impacts on the physiology of many marine organisms (Smith, 1981; Champ & Lowenstein, 1987; Horiguchi et al., 1995; Ko et al., 1995; Ruiz et al., 1995; Axiak et al., 1995; Pearce, 1996)and resulted in a worldwide ban on the use of TBT based antifouling paints in early 2003 (IMO, 1999, Champ, 2000).

To prevent settlement of larvae and spores on hull surfaces a certain amount of biocide has to be released from the paint surface into the adjacent boundary layer (Christie & Dalley, 1987). This ‘leaching rate’ of toxins decreases over time and, therefore, all vessels have to be removed from the water periodically to have their antifouling paint renewed. The service lives of non-TBT paints are variable but commonly range from 6 months to 2 years (Millet pers. comm., 2002; AMOG Consulting, 2002). Recent research on hull fouling on merchant vessels (including those using TBT based paints) and private pleasure craft, as well as earlier studies on naval vessels have all found a positive relationship between the age of the antifouling paint and the amount of fouling on a ship’s hull (Visscher, 1928; Coutts, 1999; Floerl & Inglis, 2000). On average, in tropical environments, the proportion of a vessel hull that is covered in fouling appears to increase by 10 % every five months (Floerl,2002). More than 28 % of the 137 yachts surveyed by Floerl (2002) had not renewed their antifouling paint for 18 months or longer, and most of them carried diverse assemblages of sessile organisms on their hulls.It is thus the maintenance of a vessel’s submerged surfaces that determines its susceptibility to fouling. Often not the entire area of a vessel’s hull is coated in antifouling paint. Coutts (1999) observed that 89 % of the fouling taxa recorded in his study of merchant vessel hulls (these included all non-indigenous taxa identified) occurred within the dry -docking support strips (DDSS). DDSS are those areas underneath a vessel that are in contact with the chocks used to support the vessel during dry-docking. DDSS thus lack any antifouling paint, and can constitute 5 – 20 % of a vessel’s submerged hull area (Coutts, 1999) . Ten percent of the submerged hull area of a moderately large ship (~105 m in length) may amount to 175 m

2.

Besides the length of the intervals between successive antifouling paint renewals, the usage pattern (e.g.

average cruising speed, frequency of usage, durat ion of stationary periods) of a vessel is another factor that can influence its susceptibility to colonisation by sessile organisms. Most modern paints are ablative or self-polishing systems that release biocide as the drag of passing water abrades the upp er surface of the paint layer (Christie & Dalley, 1987; AMOG Consulting, 2002). Such paints require frequent motion of the vessel for proper performance; depending on paint type, many manufacturers recommend active use on seven out of ten days (Millet pers. comm., 2001). However, many vessels, in particular private yachts and towed barges, spend extensive periods at berth or anchor. In such scenarios, microbial slimes and/or hydrolysed paint material can accumulate at the upper surface of the paints and lower or prevent the release of fresh biocide (Biggelaar, 1998, AMOG Consulting, 2002) . Floerl et al. (in review) found that, in tropical waters, yacht hulls coated in a range of modern antifouling paints became colonised by a diverse range of fouling organisms when moored stationary in boating marinas for periods of 8 – 16 weeks. More than 40 % of vessels surveyed by Floerl (2002) had spent continuous periods of > 4 months moored in foreign ports and marinas, and the activity levels of these vessels were commonly < 20 %. Vessels that use an antifouling paint that is not appropriate for their travel patterns and/or who spend excessive periods at berth or anchor are likely to become fouled prior to the end of the paint’s recommended service life and transport extensive fouling assemblages on their hulls.

There are two ways of cleaning fouled hulls – by renewing the antifouling paint or by manually removing fouling organisms using brushes, scrapers or high-pressure water blasting. These two options differ greatly in cost: renewing the paint can amount to thousands (yachts) or hundreds of thousands of dollars (large merchant ships), while de-fouling by divers or on tidal grids is considerably cheaper. However, recent research has shown that manual hull cleaning that is not followed by paint renewal has short-term benefits but longer-term penalties. Removal of fouling from a vessel hull by scrapers or stiff brushes does not entirely clean the hull, and leaves behind minute traces of the organisms including barnacle and oyster cement, byssal threads and soft tissues of sponges and ascidians (Floerl, 2002). This material can act as a positive settlement cue to the next generation of

9

fouling taxa, which frequently exhibit gregarious or associative settlement behaviour (Knight-Jones & Crisp, 1953; Crisp & Meadows, 1962; Scheltema et al., 1981; Burke, 1986; Pawlik, 1992). Experiments from Australia show that hull surfaces that are manually cleaned attract up to 5.8 times more fouling organisms over a 2-weekperiod (up to 3,045 recruits per 225 cm

2) than do surfaces that are manually cleaned and then chemically

sterilised (Floerl, 2002). Both hull maintenance practices and usage patterns of ocean-going vessels influence the susceptibility of ship hulls to colonisation by marine sessile organisms.

(ii) Characteristics of source ports

Vessels acquire the majority of hull fouling while stationary and moored in coastal ports and marinas. These environments act as hubs of domestic and international shipping movements (Carlton, 1987) and, correspondingly, many non-indigenous marine species have disjunct distributions that are centered on ports and marinas (Cranfield et al., 1998; Hewitt et al., 1999; Hutchings et al., 2002). Most ports and marinas contain a large amount of artificial habitat in the form of buoys, harbour walls, pontoons and pilings (Carlton, 1996, Minchin & Gollasch, 2003). These surfaces often comprise > 3,500 m

2 in area, and are commonly occupied by

large populations of marine sessile organisms (Glasby & Connell, 1999; Floerl & Inglis, in review).

Both the physical structure and the geographic location of port environments can influence fouling on the hulls of resident ships. Reproduction of sessile organisms in temperate latitudes occurs seasonally and in conjunction with bursts of primary production (Crisp, 1965). Ship fouling during winter months in temperate ports can thus be negligible or absent. In contrast, production and availability of propagules occurs throughout the year in the tropics, and vessels visiting tropical ports can become colonised at any given time (Millard, 1952, Crisp, 1965). For example, recruitment of fouling organisms to artificial surfaces in two tropical marinas in Queensland, Australia, occurred at 250 – 4,100 recruits per 225cm2 over a 4 -week period, and did not differ consistently between surfaces immersed during summer and winter (Floerl & Inglis, 2003). Exceptions to these patterns can occur in tropical ports that are influenced by freshwater disturbances associated with monsoonal rainfall. In a tropical marina in Cairns, Australia, which is directly connected to a seasonal creek, Floerl (2002) documented a drop in surface salinities from 36 ppt to 9 ppt following heavy rainfalls associated with a cyclonic storm. The drop in salinity was accompanied by the mortality of nearly 100% of all fouling organisms on pontoons, pilings and vessel hulls within the marina, and the recovery of the system occurred only months later. Similar patterns have been documented in other tropical and sub-tropical locations affected by freshwater disturbances (Andrews, 1973; Coates & Byron, 1991; Paerl et al., 2001).

The construction of ports and marinas locally disrupts coastal hydrodynamics through the excavation of channels and construction of barrages and walls. These features modify wave propagation and tidal currents and thereby affect the delivery and settlement of planktonic propagules in surrounding habitats (Eckman, 1983; McNeill et al ., 1992; Archambault & Bourget, 1999) . Ports and marinas exposed to prevailing waves or wind fetch are often enclosed by solid rock or cement breakwalls that provide protection from the direct force of waves. Tidal exchange between the port and adjacent coastal waters is restricted to a narrow entrance channel that allows the passage of vessels but limits flushing of the marina basin by outside waters (see chapters in Blain,1992). In a recent study, Floerl and Inglis (2003) found that the enclosure of coastal marinas by breakwallscreates an eddy system within the marina basin that locally entrains water and propagules of marine organisms during periods of incoming tides. This entrainment significantly elevates rates of recruitment to artificial surfaces including unprotected vessel hulls (see above). Up to 19 times more recruitment (>4,000 recruits per 225 cm

2)

occurred on surfaces immersed in enclosed marinas over a 4-week period than in open marinas that lacked breakwalls (Fig. 2; Floerl & Inglis; 2003). Port designs that provide protection for berthed vessels but at the same time ensure maximum flushing rates are likely to reduce the amount of fouling acquired by visiting vessels during their stay.

(iii) Biology and physiology of fouling organisms

The movement of vessels between destination ports exerts considerable physical force on organisms attached to their hulls. Organisms that are likely to be most favored on hull surfaces are those that (1) are able to tolerate residual amounts of antifouling biocide, and (2) are either sheet-like and encrusting or rigid or flexible and able to attach themselves firmly so as to prevent dislodgement (Koehl, 1984). For example, large-bodiedstoloniferous solitary ascidians are rarely found on vessel hulls, presumably as a consequence of their small attachment area to the substratum and the ease with which they can be dislocated (Floerl, 2002).

10

Figure 2. Recruitment of fouling organisms to artificial surfaces submerged in A, port environments enclosed by breakwalls and B, unenclosed (open) ports.

Some specie s within the genera Enteromorpha, Ectocarpus (both macroalgae) and Watersipora (bryozoa) exhibit a physiological tolerance to antifouling biocides, including copper, and continue to use submerged hull surfaces as a substratum for settlement (Wisely, 1 962; Callow, 1986; AMOG Consulting, 2002). The exact mechanism for this tolerance is not known but it is thought to occur either by internal detoxification or selective exclusion (Wisely & Blick, 1967; Russell & Morris, 1973) . Watersipora subtorquata and W. arcuata are common fouling organisms in shipping ports around Australia, New Zealand and California (USA), where their current distribution has most likely been achieved via vessel movements (Allen, 1953; Banta, 1969; Gordon & Matawari, 1992). During ecological surveys in recreational boating marinas in Australia, W. subtorquata was encountered on a considerable number of yacht hulls from which other fouling organisms were absent (Floerl,2002). Similar observations have been made in several New Zealand ports and marinas (A. Coutts, unpubl. data; O. Floerl, unpubl. data). Frequently, one or several other species grew epibiotically on colonies of W. subtorquata. Experiments from Australia showed that W. subtorquata can act as a ‘foundation species’ on toxic antifoulant surfaces and facilitate the recruitment of up to 22 epibiotic taxa to these surfaces (Pool, 2002,Floerl et al., in review). The tolerance of some species to toxic antifoulants may be an evolutionary process and the result of continual artificial selection (Russell & Morris, 1973). Even meticulously maintained vessel hulls may become colonised by these organisms until effective biocides have been developed.

Conclusions

Free settlement space is a major limiting resource in marine benthic communities (Dayton, 1971, Petraitis, 1995). Marine sessile organisms are therefore extremely successful at colonising any available surface. Ship hulls present large areas of settlement space comprised of a variety of micro-habitats and far from benthic predators. If not adequately protected, submerged hull surfaces will become colonised by a variety of species, and movements of vessels between distant ports can facilitate the introduction of species into areas outside their native range. The amount of fouling that accumulates on ship hulls is influenced by a multitude of factorsassociated with hull maintenance, location and design of port environments, and the physiology and biology of organisms that come into contact with submerged hull surfaces.

Acknowledgments

Data and ideas presented in this paper greatly benefited from dis cussions with Graeme Inglis (NIWA), Helene Marsh (James Cook University), Isla Fitridge (NIWA), Ashley Coutts (Cawthron Institute) and Scott Godwin (Bishop Museum).

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14

Hull Fouling as a Mechanism for Marine Invasive Species Introductions.

Proceedings of a Workshop on Current Issues and Potential Management Strategies February 12-13 2003. Honolulu, Hawaii. Edited by L.S. Godwin.

Biofouling on Merchant Vessels in New Zealand

ASHLEY D. M. COUTTS& MICHAEL D. TAYLOR

Marine Biosecurity Section, Cawthron Institute, Private Bag 2, Nelson, New Zealand; E-Mail: ashley.coutts@cawthron.org.nz

Abstract

Shipping is considered an important vector for the inadvertent transfer of non-indigenous biofouling species around the globe despite the perception that faster speeds, utilization of effective anti-fouling coatings, frequent hull cleaning and shorter residency periods has reduced their biosecurity risk. This paper describes the nature and extent of biofouling on 30 merchant vessels (ranging from 1,400 to 32,000 gross registered tonnes) based on analysis of hull inspection video footage collected by two New Zealand commercial diving companies. A new method for measuring biofouling communities is applied, which aims to incorporate the potential for various hull locations to house non-indigenous marine species. Our analysis revealed that vessels plying trans-Tasman routes and out-of-servicevessels, possessed greater levels of biofouling than more active vessels. Dry-docking support strips and sea-chest gratings generally had the highest levels of biofouling and may pose relatively high biosecurity risks. Therefore, any future biosecurity surveillance should target these hull locations for non-indigenous species

Introduction

The frequency at which non-indigenous marine species (NIMS) are being spread around the world appears to be dramatically increasing (Cohen & Carlton, 1995; Ruiz et al., 1997; Hewitt et al., 1999; Ruiz et al., 2000). Ships are considered an exacerbator for the inadvertent transfer of NIMS around the globe (Carlton, 1987; Nehring, 2001; Minchin & Gollasch, 2002). International shipping plays a vital part of New Zealand’s economy as approximately 95% of the countries exports by value travel by ship. It is thought that at least 148 NIMS have been deliberately or accidentally introduced to New Zealand through international shipping activities (Cranfield et al., 1998).

Modern-day shipping can introduce NIMS via a variety of mechanisms including ballast and bilge water discharges, biofouling or hull fouling (including de-fouling activities), sea-chests, sea-sieves, anchors, chain lockers, and piping (Carlton et al., 1995; Schormann et al., 1990). Recent studies suggest that biofouling even to the present day remains a significant mechanism for introduction, possibly more than ballast water (Cranfield et al., 1998; Thresher et al., 1999; Gollasch, 2002; Hewitt, 2002). However, what is not presently known is which vessel typeposes the greatest risk of dispersing biofouling species.

Modern-day merchant vessels were thought to pose less of a risk than other vessel types (e.g. barges, fishing vessels, oil exploratory rigs, and recreational craft) owing to their faster speeds, the utilization of tributyltin (TBT) anti-fouling coatings, frequent hull cleaning and shorter residency periods in port (Carlton & Scanlon, 1985; Campbell & Hewitt, 1999). However, relatively high levels of biofouling, including NIMS, have been witnessedwithin small areas of the hull of modern-day merchant vessels (i.e. areas lacking effective anti-fouling paint and in areas protected from strong laminar flows) (Rainer, 1995; Coutts, 1999; James & Hayden, 2000; Schultz & Swain, 2000). It is not currently known what level of biofouling (e.g. species richness, abundance, biomass etc) constitutes a significant biosecurity risk. However, “nooks and crannies” on fast moving international vessels arriving to ports worldwide could house sufficient populations of NIMS that could spawn and produce the concurrent inoculation pressure required for certain species to establish (Minchin & Gollasch, 2002).

The Ministry of Fisheries is the main government agency with the responsibility of managing marine biosecurity in New Zealand. While New Zealand does not presently have any regulations mandating the hygiene of vessel hulls, it does propose to develop a management regime for biofouling on visiting international vessels.Therefore, this paper quantifies the nature and extent of biofouling within anomaly areas of the hulls of various merchant vessels operating in and visiting New Zealand. The potential of different areas of the hull to house biofouling is then used as a basis for interpreting biosecurity risk. The approach assumes: (1) a greater diversity of biofouling taxa (i.e. , in terms of both taxa richness and relative abundance) equates to a higher likelihood of NIMS being present and that (2) more established biofouling communities constitute a greater biosecurity risk than undeveloped communities. The results have application for biosecurity managers in their need for efficient biofouling surveillance methods and for techniques to assess biosecurity risk at the border.

15

Materials and Methods

Underwater videos of the hulls of 30 merchant vessels (17 container vessels, 7 bulk carriers, 2 tankers, 2 roll-on/roll-off vessels, a supply vessel, and a passenger ferry) were randomly selected from libraries held by two New Zealand commercial diving companies. The vessels either visited New Zealand on a regular basis or were resident there and ranged from 1,400 to 32,000 gross registered tonnes (GRT). The vessels had been videoed in situ between 1992 and 1999 immediately prior to in -water cleaning in Auckland, Tauranga, or Wellington. Information on vessel type, maintenance history and voyage details of the vessels were obtained from records held by the diving companies, Maritime Data Services and the New Zealand Ship and Marine Society.

Video footage targeted for quantitative sampling included areas of the hull (hull location) lacking anti-fouling paint (propeller), areas with inactive or old anti-fouling paint (dry-docking support strips – DDSS); areas that often had damaged paint (bulbous bow) and areas thought to provide relatively protected habitats from strong hydrodynamic flows (bilge keel; rudder; rope guard, and sea-chest gratings). The area outside of the DDSS (OutDDSS) on the bottom of vessels was also included for comparative purposes. Quantitative sampling of the bow thrusters and sides of the hull was not possible owing to insufficient video footage of these areas (Fig. 1).

Figure 1. Position of various hull locations sampled during this study (DDSS – the positions under a vessel that cannot be painted with fresh anti-fouling paint during a dry-docking because of the position of docking blocks).

During viewing, the video was paused at random (five times) within each of the 8 hull location on as many of the vessels as possible. Taxa richness (number of biofouling taxa) and percentage cover data was derived using 50 random points marked on a 0.33 m television monitor. Bare metal, anti-fouling paint, and fifteen biofouling taxa (i.e. higher taxonomic groups) corresponding to four biofouling categories, as shown in Table 1, were used as a basis for describing the nature and extent of the biofouling within and among the vessels. Only those hull locations described above were analyzed, hence levels of biofouling outside these locations were not considered (i.e. such as along the waterline or the flat sides where certain taxa such as algae are more likely to be present).

Table 1. Biofouling categories used in the study.

A B C D

Bare metal Fine green algae Acorn barnacles Solitary ascidians

Anti -fouling paint Fine brown algae Tubeworms Compound ascidians

Filamentous green algae Coralline algae Sea anemones

Filamentous red algae Bryozoans Mussels

Hydroids Oysters

Macrolagae

The 4 biofouling categories correspond to a combination of the general succession and survivorship of biofouling observed and documented on artificial structures in the literature (e.g. Marine Corrosion Sub-Committee,1944; Bishop et al., 1949; Pyefinch, 1950; Woods Hole Oceanographic Institution, 1952; Skerman, 1960; Coutts, 1999; Lewis, 2002a). Diatom and bacterial slimes could not be distinguished from bare metal and anti-fouling paint with any certainty and hence were not included in the study as separate taxa. Furthermore, owing to insufficient

Super-structure

Bow thruster

Bilge keelsSea-chest

gratings

Rope guard

Propeller

Upper anti-fouling paint margin

DDSS OutDDSS

Rudder

Bulbous bow

16

clarity of the video footage, no mobile biofouling organisms were observed and were therefore not included in the study.

The percentage cover data was also used to identify vessels and hull locations that contained a relatively high percentage cover of the higher taxonomic groups (i.e., biofouling categories C and D in Table 1). The percentage cover data for all taxa in categories C and D was weighted by 1, whereas the percentage cover data for categories A and B was weighted by 0. This weighted percentage cover data was used as a simplistic basis for interpreting biosecurity risk under the assumptions described previously. Data was analyzed using general linear models and multivariate analyses in SAS/STAT (1990) and PRIMER–E Ltd Version 5.0. (1998).

Results and DiscussionBiofouling patterns - vessels

The archived video footage of underwater hull assessments proved to be a cost-effective way of quantifying levelsof biofouling taxa at selected hull locations on a wide range of merchant vessels visiting or operating in New Zealand waters. It is important, however, to note that the majority of the 30 vessels analysed probably possessed anti-fouling paint that was in excess of 36 months old given that these vessels were either requiring an in-water hull clean or a dry-docking extension. Therefore, considering that the effectiveness of modern-day anti-fouling paints at resisting biofouling declines with age, the levels of biofouling encountered in this study were probably approaching worst-case biofouling scenarios typical of merchant vessels.

In light of the above, it was therefore not surprising that all 30 vessels surveyed were fouled with at least one of the 15 taxonomic groups used in the study. Of the 3 vessel types, the 6 vessels classified as ‘other’ were the most fouled, having the highest mean taxa richness (per vessel), mean percentage cover and mean weighted percentage cover of biofouling taxa. All 6 vessels in this category traded either domestically throughout New Zealand or across the Tasman Sea (between Australia and New Zealand). Furthermore, all vessels with category D taxa present were domestic or trans-Tasman vessels. Generally this is because vessels plying similar latitudes with relatively short voyage durations are known to possess higher levels of biofouling than vessels that visit ports separated by vast latitudinal distances (Visscher, 1928; Woods Hole Oceanographic Institution, 1952; Skerman, 1960; Coutts, 1999; Lewis, 2002a).

In contrast, many of the international container and bulk carrier vessels that possessed relatively low mean taxa richness and percentage cover of biofouling organisms were often restricted to category B and C taxa (Fig. 2).Such international vessels generally expose biofouling organisms to long voyages at fast speeds, as well as relative extremes in temperature and salinity levels (e.g. crossing the equator). Hence, only the more hydrodynamic-insensitive (e.g. cosmopolitan algae, acorn barnacles, tubeworms, and encrusting bryozoans) are able to survive upon such vessels. Two container vessels in particular possessed the highest levels of biofouling across hull locations out of all the vessels surveyed, and both vessels had category B, C and D taxa present. Significantly, these were also trans-Tasman vessels and each had spent a minimum of 3 months laid-up in Auckland Harbour since their last dry-docking. Considering most merchant vessels presently utilise self-polishing copolymers (SPC) paints, which require water movement to expose a fresh surface from which the toxic biocide is released, such extended inactivity results in insufficient biocide release needed to prevent biofouling.

Biofouling patterns - hull locations

Multivariate analysis grouped the 8 hull locations amongst vessels into 3 main groupings: 1) propeller; 2) bulbous bow, bilge keel, rudder and rope guard, 3) OutDDSS, DDSS and sea-chest gratings according to similarities in the presence, absence and abundance of anti-fouling paint, and the 15 biofouling taxa. Patterns of biofouling amongst these hull locations can generally be explained by one or a combination of the following factors: the presence, absence or effectiveness of anti-fouling paint, availability of sunlight and exposure to hydrodynamic flow.

17

Figure 2. Percentage cover of the 4 biofouling stages (see Table 1) within each hull location for the 3 vessel types used in the study. n refers to number of vessels surveyed within each vessel type category. Gratings refers to sea-chest gratings.

Propellers for instance, are a unique hull location because they do not possess anti-fouling paint, just a non-toxic brass surface. However, the challenge for biofouling organisms is not to just colonise such a structure, but to survive the harsh turbulent environment while the propeller is in motion. This might explain the dominance of hydrodynamic-insensitive taxa with high percentage cover (i.e. brown and green surface algae, acorn barnacles, tubeworms and coralline algae), particularly towards the centre of propellers where hydrodynamic forces are much lower than at the extremities of the blades.

Bulbous bows, bilge keels, rope guards and rudders formed a second grouping owing to the presence and similar abundance of predominantly the three algal taxa (i.e. fine brown, fine green and filamentous green algae).Not surprisingly, this is largely explained by such locations receiving a plentiful supply of sunlight. Although bilge keels are often at depth, the angle of the bilge keels to the hull is such that the upper facing surface receives more available light than the adjacent flat surfaces. Furthermore, invertebrates were also noted living on the edges and onthe undersides of the keels. According to Godwin & Eldredge (2001) and Godwin (2003) anti-fouling paint often wears off along the edges of bilge keels and weld seams making these surfaces susceptible to biofouling, and paint manufactures stress that premature drying of anti-fouling paint can cause the anti-fouling paint to peel off around such areas. Moreover undersides of the bilge keels provide sheltered areas where various biofouling organisms can survive.

A

B

C

D

0

20

40

60

80

100

0

20

40

60

80

100

0

20

40

60

80

100

Bulb

ous b

ow

Bilg

e k

ee

l

D

DS

S

OutD

DS

S

Pro

pelle

r

Ru

dd

er

Rope g

uard

Gra

tings

Hull location

%

Co

ver

Container vessels (n = 17)

‘Other vessels’ (n = 6)

Bulk carriers (n = 7)

Biofouling Category

18

Interestingly, rope guards and rudders in particular also possessed a variety of invertebrate taxa. Similarly, although bulbous bows are probably subjected to some of the greatest hydrodynamic forces on merchant vessels, the anchor chains often remove the anti-fouling paint from this location while the vessels are at anchor, thus providing a non-toxic surface for biofouling organisms to colonise. However, only those biofouling taxa that are hydrodynamically -insensitive are capable of surviving in such areas (i.e. category B and C taxa: Koehl, 1982;Denny, 1988).

The third grouping of hull locations (i.e. OutDDSS, DDSS and sea-chest gratings) were grouped together due to their relatively low abundance of algal taxa and high abundance of anti-fouling paint. This is because these locations, especially OutDDSS and DDSS receive very little sunlight due to the shading effects of bilge keels.OutDDSS were the least fouled hull location on average because these areas usually possess effective anti-foulingpaint due to their exposure to strong hydrodynamic forces as well as being shaded from light by the bilge keels, especially in turbid waters. In contrast, however, the OutDDSS of the two most heavily fouled vessels mentioned previously were colonised by a range of biofouling taxa. It seems that the inactivity of these vessels resulted in the SPC paints being ineffective. In a similar context, Preiser & Ticker (1985) found that DDSS provided a nucleus for invertebrates to migrate into surrounding areas (OutDDSS) as a result of the leaching rates of the anti-fouling paints declining with time.

Although DDSS may be subjected to relatively strong hydrodynamic forces, this location was often colonised by category C and D taxa, including a relatively high mean weighted percentage cover for all 3 vessel types. Such areas usually possess old and ineffective anti-fouling paint, providing invertebrates with a suitable non-toxic surface to colonise. Furthermore, given DDSS are located at depth (5-10 meters), they are not as frequently exposed to freshwater as upper regions of the hull (e.g. when visiting freshwater dominated ports), which may also contribute to the prolonged survivorship of particular biofouling organisms within this location.

Statistical modeling showed that differences in the mean weighted percentage cover data were dependent on vessel type. DDSS, propeller, rope guard, sea-chest gratings and rudder locations all had relatively high mean values for the ‘other’ vessel type category, and DDSS had relatively high mean values for all 3 vessel types (Fig. 3).DDSS and sea-chest gratings had the highest mean weighted percentage cover of the higher taxonomic groups (i.e.

categories C and D), which suggests that these locations may have the greatest likelihood of possessing NIMS.Interestingly, Coutts (1999) also found that in a sample of merchant vessels visiting Tasmanian waters, DDSS had 89% of the taxa encountered, including all of the NIMS. Therefore, future surveillance of vessels should focus their attention on these protected areas.

Figure 3. Mean (±1 se) weighted percentage cover within each hull location for the 3 vessel types used in the study.See text for definitions of weighted percentage cover and hull locations. Gratings refer to sea-chest gratings.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Bilg

e k

eel

D

DS

S

OutD

DS

S

Pro

pelle

r

Rudder

G

ratings

Rope g

uard

Container

Bulk carriers

Other

Bulb

ous

bow

Mea

n

wei

gh

ted

% c

over

Hull location

19

Biosecurity risk

Determining biosecurity risks from biofouling is a complex task. Many tools such as dried biomass, species richness, species diversity and percentage cover of biofouling organisms upon vessels’ hulls have been used to assess either the performance of anti-fouling paints and better understand biofouling processes (Visscher, 1928; Pyefinch, 1950; Woods Hole Oceanographic Institution, 1952; Cologer & Preiser, 1984), or to identify vessels and hull locations that present biosecurity risks (Skerman, 1960; Huang et al., 1979; Rainer, 1995; Coutts, 1999; James & Hayden, 2000; Godwin & Eldredge, 2001; Gollasch, 2002; Minchin & Gollasch, 2002; Godwin, 2003). However many of these assessments have been descriptive only.

The weighted percentage cover response variable used in this study provided an alternative approach as it took into account not only the nature and extent of the biofouling, but also the development and growth of the biofouling community. However, this variable is clearly simplistic in terms of the information it provides or biosecurity risk. Importantly, the presence of biofouling and NIMS upon the hulls of vessels in New Zealand does not equate to a significant biosecurity risk. Risk also depends on whether the NIMS are already present in the country or at any new location, as well as the potential for establishment and any negative (and positive) impacts.

Management

Unfortunately biofouling within DDSS is an inevitable consequence of the dry-docking procedure, unless vessels are re-floated and the docking blocks relocated. While many naval vessels around the world can justify the cost of this re-floating procedure, the cost of re-floating merchant vessels at present exceeds the cost of the increased fuel consumption imposed by leaving such areas unpainted. Both the shipping industry and marine biosecurity agencies would welcome a solution to prevent biofouling within DDSS. These areas can represent between 5-20% of the submerged area of the hull, and significantly contribute to fuel consumption (Preiser & Ticker, 1985).

Furthermore, Preiser & Ticker (1985) devised a way of applying adhesive anti-fouling paint pads to the docking blocks prior to a vessel’s docking, so that when the vessel departed the dry-dock these normally unprotected areas were treated with anti-fouling paint. As far as the authors are aware, this technology has not been pursued any further. Also, there are anti-fouling paints that can be applied underwater, and these could be used to protect DDSS as well as damaged regions of the hull.

Inner regions of propellers could be painted with anti-fouling paint, although the paints would need to be slow-polishing and may only last for a short period of time. Fortunately, it is common practice for vessels in some countries to undergo a propeller polish as required. However the biosecurity risks of de-fouling are currently being evaluated in New Zealand, and managed in some states of Australia (i.e. Victoria) by prohibiting in-water cleaning of vessels over 200 gross tonnes (EPA, 1999).

It is common practice for the same type of paint to be applied to the entire submerged area of the hull.However, various types of anti-fouling paints such as soluble matrix, contact leaching SPC, controlled depletion polymer, fouling-release and non-toxic coatings (see Lewis, 2002b) are being trialed on a variety of vessels within various locations to better prevent biofouling (John Lewis, pers. comm.). It is significant to note that the most effective anti-fouling paint produced to date, tributyltin (TBT), will be phased out of use by 1 January 2008 (IMO, 2001). This means that the application of anti-fouling paints that have been specially formulated for use on various types of vessels and hull locations, is of paramount importance from a biosecurity perspective (Lewis, 2002b).

Acknowledgements

We would like to acknowledge the assistance of the two diving companies, Divers Services Ltd and New Zealand Diving and Salvage Ltd, who provided the underwater hull inspection video assessments of the vessels used in this study. Furthermore, we would like to extend our thanks to Michael Pryce from the New Zealand Ship and Marine Society in providing valuable information on each of the vessels. Thank you also to DMP Statistical Solutions(University of Auckland) for statistical advice. Useful comments on the manuscript were provided by Barrie Forrest (Cawthron) and Chad Hewitt (Ministry of Fisheries). This research was funded by the New Zealand Foundation for Research, Science and Technology (FRST).

20

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Hull Fouling as a Mechanism for Marine Invasive Species Introductions.

Proceedings of a Workshop on Current Issues and Potential Management Strategies February 12-13, 2003. Honolulu, Hawaii. Edited by L.S. Godwin.

Potential for the introduction and spread of marine pests by private yachts

OLIVER FLOERL & GRAEME J. INGLIS

National Centre of Marine Biodiversity and Biosecurity, National Institute of Water and Atmospheric Research, P.O. Box 8602, Christchurch, New Zealand; Email: O.Floerl@niwa.co.nz

Abstract

Recreational boating is a booming industry worldwide, and movements of domestic and international yachts constitute the majority of inshore vessel movements in many coastal countries. Hull fouling on private ocean-going yachts has been implicated as a vector in the introduction and secondary spread of a number of aquatic nonindigenous species (NIS). Despite this, there are no existing quarantine procedures for international yachts to prevent the introduction of fouling organisms into native marine systems. The development of predictive tools that allow quarantine officials to efficiently discriminate low-risk vessels from those that may pose a risk to marine biosecurity would help reduce the number of propagules that reach native environments and, therefore, the number of marine NIS that may establish and become spread.

Private craft as transport vectors for marine organisms

In freshwater environments, private (recreational) vessels are known to facilitate the spread of both aquaticinvertebrates and plants. Trailered overland boat traffic between rivers and lakes is the major mode by which recreational vessels facilitate the spread of the zebra mussel Dreissena polymorpha and exotic macrophytes through New Zealand and the U.S.A. (Johnstone et al., 1985; Johnson & Padilla, 1996; Buchan & Padilla, 1999, Johnson et

al., 2001). Transport of these taxa occurs primarily by entanglement of fragments or individuals in fishing gear, anchor chains, and boat trailers.

Movement of marine organisms by recreational vessels is likely to occur primarily by hull fouling. In contrast to freshwater environments, the majority of large recreational vessels in marine environments are not kepton trailers but are moored permanently in coastal boat harbours (“marinas”). The permanent exposure of these boats to marine waters means that they will develop substantive fouling assemblages on their hulls if these are not adequately protected (see paper by Floerl in this volume and references therein). In contrast to commercial ships, there are no profit-related incentives (e.g. deadlines, competition, speed) for regular paint renewal on recreational vessels. Therefore, the intervals at which owners of recreational vessel renew the antifouling paint on their vessel are more variable, and more often exceed the recommended service life of the paints, than those of commercial ships. In Australia, Floerl (2002) sampled the hulls of 70 domestic and international yachts that had been continuously exposed to marine waters for periods ranging from one week to ten years. On average, boats that had not been cleaned within the last 20 months and which had resided in a marina for >8.5 months (38 % of sample) had 75.5 %of their submerged hull surfaces covered by fouling organisms (Floerl, 2002). In total, 47 different taxa were encountered on the hulls that were sampled. Similarly, of 27 international yachts surveyed in a marina in Auckland, New Zealand, all had some type of growth on their hulls, with between 0.02 % and 88 % (mean = 42 % cover) of available hull surfaces covered by fouling assemblages consisting of at least 30 different taxa (James & Hayden, 2000).

Recreational vessels have been implicated in the transport of several well known non-indigenous marine species. Below we provide a short summary on some notable species and studies:

1. The Japanese kelp, Undaria pinnatifida, was first observed in New Zealand in 1987, and is thought to have arrived on fishing vessels from Korea, Japan or Taiwan (Hay & Luckens, 1987; Hay, 1990). Since its initial discovery, U. pinnatifida has spread to at least 15 other ports and harbours around New Zealand. Natural rates of spread of this species are in the order of 10’s to 100’s of metres per year, but long distance transport (km’s to 100’s of km’s) is thought to occur primarily by hull fouling on domestic vessels including fishing boats and yachts (Hay,1990; Forrest et al., 2000). U. pinnatifida was found on the hulls of 25% of recreational vessels moored within

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Lambton Harbour (Wellington), and its spread in this region was attributed, at least in part, to the movement of vessels that had been laid up for long periods (Hay, 1990). The impact of the invader on native plants and animals is not fully understood, but it is suspected that the prolific growth and competitive ability of the species enables it to displace dominant native macroalgae (Talman et al., 1999). U. pinnatifida is also spreading around parts of the coastlines of Australia, France, and England. Especially in England, boating marinas are often “hot spots” of abundance, and recreational vessels appear to be the principal means by which Undaria has been spread (Fletcher & Farrell, 1998).

2. The broccoli weed, Codium fragile spp. tomentosoides, is native to South East Asia, but has been spread throughout the North-East Atlantic, the Mediterranean and, more recently, along the North American shore from Nova Scotia to North Carolina (Trowbridge, 1998, Chapman, 1999). Hull fouling is though to be one of its main spreading mechanisms (Carlton & Scanlon, 1985). Codium’s establishment in Nova Scotia has been attributed to a yacht arriving from overseas (Bird et al., 1993). Its impacts include fouling of fishing nets, fouling and displacingnative and commercial shellfish species, changes in sedimentation rates and nutrient cycling, and heavy fouling of manmade structures such as wharfs and pilings (Trowbridge, 1998, Talman et al., 1999).

3. The black striped mussel, Mytilopsis sallei , and the Asian green mussel, Perna viridis. Recreational vessel movements have also been implicated in the introduction and spread of these two extremely prolific bivalves. The black striped mussel is an estuarine relative of the zebra mussel Dreissena polymorpha , whose invasion into the North American Great Lakes and river systems causes ecological and economic impacts amounting to 100s of millions of U.S. dollars per year (Nalepa & Schloesser, 1993; Pimentel et al., 2000). M. sallei is native to Central America and the Caribbean, and was introduced to a number of marinas around Darwin, Australia, in March 1999 by overseas yachts (Thresher, 1999; Field, 1999; Centre for Research on Introduced Marine Pests, 2001).Eradication of the black striped mussel was successful but costly: it involved the tracking and sterilisation of more than 400 recreational fishing boats and yachts that had resided within the infected marinas during the months preceding the pest outbreak (Bax et al, 2001; Marshall pers. comm. , 2000). M. sallei has also invaded coastal waters of India, where it has heavily colonised and damaged submerged manmade structures (Ganapati et al., 1971; Rao et

al., 1989).

Perna viridis was recently introduced to the port of Cairns in Queensland, Australia. Its local distribution is currently restricted to a small population in the vicinity of marinas and on the hulls of recreational vessels. However, regional environmental authorities are on alert as the species can cause impacts similar to M. sallei (Neil pers.

comm., 2002). P. viridis has also been introduced into the Gulf of Mexico, the southern Caribbean, Florida, and Japan (Benson et al., 2001; Ingrao et al., 2001).

4. The serpulid tubeworm Ficopomatus enigmaticus. The native origin of this species is unknown but, during the past century, F. enigmaticus has been introduced to the coastal waters of Europe, the U.S.A., and New Zealand (Read & Gordon, 1991; Cranfield et al., 1998). It appeared in New Zealand in the 1960s and the location of its discovery – on piles, pontoons and pleasure boats in Whangarei Harbour – suggested it had been introduced in the fouling assemblage of an overseas yacht. Extensive nuisance growths occurred within Whangarei Harbour, with encrustations up to 23 cm thick observed on some vessel hulls (Read & Gordon, 1991). F. enigmaticus was subsequently spread - most likely by domestic boat movements - to more southern locations around New Zealand where it caused problems by fouling water intakes of power and flood protection stations (Read & Gordon, 1991; Probert, 1993). Dense aggregations of F. enigmaticus can also influence water quality of coastal ports and marinas (Davies et al., 1989).

The list of species presented above is not exhaustive. Recreational yachts have also been implicated in the transport of the invasive alga Caulerpa taxifolia and non-indigenous ascidians and bryozoans in Europe, Australia, and the U.S.A. (Meinesz et al., 1992; Sant et al., 1996; Lambert & Lambert, 1998; Lützen, 1999; Floerl, 2002).

Recreational boating – a growing pastime, lifestyle and industry

In recent years there has been an increase in the number of recreational vessels such as yachts and cabin cruisers in countries like Australia, New Zealand, and the U.S.A, as well as in the number of boats traveling between continents (Freedonia, 1998; Floerl & Inglis, 2000). In the state of Queensland, Australia, the number of permanently moored vessels (> 6 m) doubled between 1985 and 2000, from ~ 8,000 to ~16,000 (Floerl, 2002; Fig. 1). By 2002, there were more than 76,000 such vessels (annual reports of Australian State maritime registration authorities). A similar trend has occurred in New Zealand, where the exact number of private vessels is not known, as registration is not

24

mandatory, but it has recently been estimated at approximately 16,500 (New Zealand Marine Safety Authority, 1999).

Figure 1. Numbers of coastal boating marinas (circles) and registered recreational vessels of >6m length (diamonds) in Queensland, Australia (Figure from Floerl, 2002).

Marinas provide ideal conditions for the incubation and spread of fouling organisms. They are often protected from wind and waves, and the movement of water within marinas occurs at velocities of 1-20 % of those observed in adjacent coastal locations (Floerl & Inglis, 2003). Marinas generally contain an abundance of differenttypes of hard surfaces (e.g. vertical pilings, horizontal floating pontoons, rock breakwalls) that are ideal for organisms to colonise and can amount to > 3,500m2 in area. In many cases, nearly 100 % of submerged pontoon and piling surfaces in marinas are covered in assemblages of sessile organisms (Floerl, 2002). In addition, most marinas contain a large number (100 – 1,200) of boats, many with hulls susceptible to colonisation by fouling organisms. Coastal boating marinas are the main hubs of yacht movements, with vessels arriving and departing at all t imes.The number of coastal boating marinas has increased in accordance with the increase in recreational vessels. In Queensland, for example, the number of marinas has risen from ~ 5 in 1960 to ~ 59 in 2001 (Floerl, 2002; Fig. 1).Similar trends have occurred in New Zealand and other parts of the “developed” world (Richardson & Ridge, 1999).A recent industrial survey carried out in 1998 forecasted an annual market increase of 7.3 % for the United States recreational boating industry, resulting in a US$14.2 billion market in 2002 (Freedonia, 1998). Globally, an increasing number of people are moving to the seacoast and, consequently, the numbers of recreational boats and marinas are likely to continue to rise.

Biosecurity risks of international yachts

Private yachts can pose different types of risk to the marine biosecurity of coastal countries: (1) the introduction of previously absent marine NIS, and (2) the secondary spread of already established marine NIS. While new introductions to a country (or native ecosystem) can only be facilitated by boats arriving from overseas (or from locations outside the native ecosystem), the secondary dispersal of established marine NIS can be accomplished by both domestic and foreign vessels (Inglis & Floerl, 2002).

International arrivals (or arrivals from outside the native system)

Many countries worldwide are frequented by visiting international yachts. For example, 650 - 950 and 400 - 550international recreational vessels enter Australian and New Zealand waters every year, respectively (Grant & Hyde, 1991; Floerl, unpubl. data, 2002-2003). In the case of Australia, these arrivals are evenly spread between the 35 designated ports of entry, although more boats tend to arrive on the east coast of the country (Australian Customs Service, pers. comm., 2002). In New Zealand, in contrast, where there are 16 designated ports of entry,approximately 85 % of all international arrivals clear customs in a single port, the Opua Marina located in the northwest of New Zealand’s North Island (Grant & Hyde, 1991; Floerl unpubl. data, 2002-2003). A large number of

25

boat arrivals in a given location may be associated with a relatively high delivery of propagules, and increase the risk of unwanted introductions (Minchin & Gollasch, 2003).

Of course, the arrival of viable organisms on the hulls of overseas boats is in part dependent on: (1) the recent travel history of the vessels (i.e. which other ports or locations have been visited) and (2) the physiological tolerance range (e.g. temperature, salinity) of the organisms on the hull. Between October 2002 and December 2003, the 339 international vessels that entered New Zealand had previously departed from a total of 42 different ports, most of which were located within the tropics (Floerl unpubl. data, 2003). It is likely that in this and other, similar situations a large proportion of hull assemblages may perish en-route by a large drop in water temperature (Minchin & Gollasch, 2003). However, when boats travel between tropical ports (e.g. Hawaii to Fiji or Papua New Guinea to NE Australia) the chances of survival will be better. There have been numerous accounts of fouling organisms surviving extensive coastal or inter-oceanic voyages of long duration and between different physical environments and therefore, survival of some taxa during voyages across physical gradients can not be ruled out entirely (Bertelsen & Ussing, 1936; Allen, 1953; Crisp, 1958; Foster & Willian, 1979; Carlton & Hodder, 1995; Gollasch & Riemann-Zuerneck, 1996; Apte et al., 2000).

Domestic vessel movements

Studies of the spread of marine NIS by recreational boats in freshwater environments show that the risk of invasion of an area is not simply a function of how many vessels an area receives. The frequency with which boaters move between regions containing problem species is also of importance (Padilla et al., 1996; Johnson et al., 2001). This is also likely to be true of marine environments. Individual transport events often fail to result in the establishment ofnew populations. The likelihood of success is related more to the frequency of transport events between infested and susceptible locations (Ruiz et al,. 2000).

A questionnaire survey of boat owners in north-eastern Australia showed a relatively high incidence of regional movement by cruising yachts around the eastern Australian coastline (Floerl, 2002; Fig. 2a). Although most (70 %) trips by domestic vessels did not extend more than 100 km from the vessels’ homeport, respondents to the survey had visited a total of 41 different locations throughout Australia in the previous 18 months. There was particularly high exchange of boats between ports separated by 300 to 400 kilometres of coastline, and a high degree of ‘connectivity’ between the various coastal ports and marinas (Floerl ,2002; Fig. 2b). This high frequency of domestic boat movements is a main reason for the concern of environmental managers about the risk of rapid, human-mediated spread of aggressive invaders such as the black striped mussel and the Asian green mussel, both of which have established populations close to centers of boating activity (A. Marshall & K. Neill pers. comm., 2002).Secondary spread of marine NIS can be facilitated by both domestic and international boats cruising between points of infestation and uninvaded habitats. Following their arrival in a port, many international yachts spend extended periods moored alongside domestic yachts. In Australia and New Zealand, for example, residency times of overseas yachts in coastal marinas typically range from a few days to eight months or longer (James & Hayden, 2000; Floerl, 2002; Floerl unpubl. data, 2002-2003).

Prevention and management of biosecurity risks posed by overseas yachts

With the exception of ports and marinas around Darwin, Australia, there are no existing quarantine procedures for arriving yachts to prevent the transport of fouling organisms into New Zealand, Australia or any other country. In both New Zealand and Australia quarantine officials check arriving vessels for insects, plant seeds and pets (and their diseases) to limit quarantine risks to human health, agriculture and terrestrial environments (Grant & Hyde, 1991; New Zealand and Australian Customs Services pers. comm., 2001-2003). However, upon entry into Darwin’s four marinas, internationally traveled vessels are required to go through another inspection by the Northern Territory Fisheries Department. Any vessel that has not renewed its antifouling paint since its arrival in (or return to) Australia is slipped and the hull inspected. If the tides or boat structure do not make this feasible then the hull is inspected by divers. In addition, the internal plumbing systems of internationally travelled vessels are subjected to a 5%detergent treatment held in by seacocks for a 14 hour period. To date, approximately 30 potential pest introductions have been intercepted by the inspection of over 700 yachts (A. Marshall, pers. comm., 2003). In all other Australian and New Zealand ports of entry, submerged hull surfaces of yachts are occasionally checked for illegal objects or attachments, but never for potential problem species they may carry.

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Figure 2. A, Coastal ports and marinas visited over an 18-month period by 118 domestic and international yachts surveyed in six coastal marinas in Queensland, Australia (white circles). B, Twenty-one yachts surveyed in the Townsville marinas that had previously visited 23 ports and marinas up to 3, 500 km away.

Screening systems and risk assessment models have been developed for ballast water (e.g. the Australian Ballast Water Decision Support System (BWDSS); Australian Quarantine & Inspection Service, 2001) and imports of terrestrial plants and animals (e.g. Ruesink et al., 1995; Daehler & Carino, 2000). Similar tools are required for managing the risk of introducing and spreading marine NIS on the hulls of ocean-going vessels. The development of predictive tools that allow quarantine officials to effectively discriminate low-risk vessels from those that may pose a risk to marine biosecurity would help reduce the number of propagules that reach native environments and therefore, the number of marine NIS that may establish and (become) spread.

Failure to incorporate hull inspections into standard quarantine procedures and to develop predictive tools for the quantification and management of biosecurity risk factors of private yachts will have two important consequences. First, it will leave a loophole for marine NIS to enter native ecosystems. Given that an enormous amount of effort and money are being spent on the prevention or limitation of ballast water mediated marine NIS introductions, this loophole is counterproductive. Second, failure to quantify the biosecurity risk posed by private yachts and to reliably discriminate between low and high-risk vessels may result in subjective perceptions of biosecurity risks posed by both international and domestic yachts rather than estimates supported by empirical data.

Acknowledgments

The collection of field data in Australia (1999-2002) was made possible through the help of many volunteers. The ongoing data collection in New Zealand is facilitated by the MAF Quarantine Service and the New Zealand Customs Service. Special thanks are due to Kevin Kennett and Mike Cartwright (MAF Quarantine) and Grant Horneman and Geoff Wilson (NZ Customs). Thanks are due to Nick Gust and Barbara Hayden for commenting on an earlier draft.

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29

Hull Fouling as a Mechanism for Marine Invasive Species Introductions.

Proceedings of a Workshop on Current Issues and Potential Management Strategies

February 12-13 2003. Honolulu, Hawaii. Edited by L.S. Godwin.

Slow-moving barge introduces biosecurity risk to the Marlborough Sounds, New Zealand

ASHLEY D. M. COUTTS

Marine Biosecurity Section, Cawthron Institute, Private Bag 2, Nelson, New Zealand; E-Mail: ashley.coutts@cawthron.org.nz

Abstract

The movement of non-indigenous marine biofouling organism s around the world has largely been associated with international shipping. However, slow-moving vessels, particularly towed structures have clearly illustrated their potential to disperse marine biofouling organisms. In December 2001, Cawthron Institute discovered an extensively fouled barge while undertaking a routine biosecurity survey of Shakespeare Bay, Marlborough Sounds, New Zealand. Upon closer inspection, divers estimated a total of 25,941 kg of wet biomass weight of biofouling was present on the hull of the Steel Mariner, including a newly recorded colonial ascidian Didemnum vexillum behaving in an invasive manner (i.e. 1,397 kg present on the hull and a further 460 kg established on the seabed below). D. vexillum is considered a serious biosecurity threat to New Zealand’s Greenshell™ mussel aquaculture industry given the species preference for artificial structures and its smothering/biofouling capabilities. The species has also naturally spread to a neighboring barge and infected 70 of 173 (40%) of the Waimahara wharf piles 500 m away. Controversy exists over the species origin, hence the responsibility for managing the spread is unclear and unprecedented, and hence little has been done to date to manage the species.

IntroductionThe accumulation of marine growth on the outside of ships’ hulls (biofouling) is beginning to be acknowledged, particularly in the southern hemisphere, as one of the single most important vectors for the dispersal of non-indigenous marine organisms (NIMS) (Cranfield et al., 1998; Thresher et al., 1999; Hewitt, 2002; Gollasch, 2002). The New Zealand Ministry of Fisheries (MFish) is the lead government agency responsible for protecting New Zealand from the arrival and adverse impacts of NIMS. MFish largely focuses on preventing introductions of marine pests, because eradicating or managing pests is extremely difficult once they become established. However, for MFish to effectively prevent the introduction of unwanted biofouling organisms to New Zealand, they must firstly know which vessels possess the greatest biosecurity risk.

In 2002, there were approximately 3,421 international vessel visits to New Zealand: 2,581 merchant vessels, 794 pleasure craft, 34 passenger ships and 12 barges/tugs (Biosecurity Council, 2003). Unfortunately, it is not currently known which of these vessel types pose the greatest biofouling biosecurity risk. For instance, relatively high levels of biofouling, including NIMS, have been witnessed within small areas protected from strong laminar flows and in areas lacking effective anti-fouling paint of fast-moving merchant vessels (Rainer, 1995; Coutts, 1999; James & Hayden, 2000; Schultz & Swain, 2000). Furthermore, the high frequency of visits by such vessels may increase the likelihood of biofouling organisms experiencing suitable environmental conditions for spawning and successful establishment (Minchin & Gollasch, 2003).

Alternatively, the biosecurity risks might be greater on slow-moving vessels such as barges, oil exploration rigs, floating dry-docks, chartered fishing and recreational vessels. For instance, such vessels typically spend prolong periods of time stationary, during which time their anti-fouling paints become inactive and are colonized by a wide range of organisms. As a consequence of their slow-movement, large accumulations of biofouling, including NIMS are capable of surviving long voyages to new locations (Foster & Willan, 1979; Hay, 1990; Hay & Dodgshun, 1996; DeFelice, 1999; Field, 1999; Apte et al., 2000; Godwin & Eldredge, 2001; Coutts, 2002a; Godwin 2003).

While the frequency of visits of such vessels around the world could be considered relatively low, because of their long residency periods, mature biofouling communities may undergo several spawning events during their visitto foreign locations, thus increasing the probability of a successful incursion (Foster & Willan, 1979; Field, 1999; Apte et al., 2000; Coutts, 2002a). Furthermore, such slow-moving vessels are also known to be responsible for the secondary spread of unwanted biofouling organisms after their initial establishment, such as, the Japanese seaweed Undaria pinnatifida throughout New Zealand (Hay, 1990), and the zebra mussel Dreissena polymorpha throughout Europe and northern America (Minchin et al., 2002).

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The following paper documents a case study about how a slow-moving barge successfully translocated a variety of biofouling species from the North Island to the South Island of New Zealand. One of these species in particular, a sea squirt, Didemnum vexillum has never been recorded before and its introduction to the Marlborough Sounds poses a serious biosecurity threat to the Greenshell™ mussel (Perna canaliculus) aquaculture industry in New Zealand.

The discovery of the Steel MarinerOn 18 December 2001, Cawthron Institute divers noticed the heavily fouled dumb (not powered) barge Steel

Mariner moored west of Kaipupu Point, Picton (Fig. 1) during a routine biosecurity survey of Shakespeare Bay, Marlborough Sounds. Upon inspection, divers observed a colonial ascidian of the genus Didemnum smothering the bottom of the barge and the seabed immediately below. Further quantitative surveys on 26 February 2002 revealed a total of 6 different algal species and 70 animal taxa identified from the hull. During these quantitative surveys as many as 41 different marine organisms were identified from a single 0.25 m2 quadrat area with an average of 28 species per 0.25 m2.

The wet biomass weight of biofouling on the hull of the Steel Mariner varied from as little as 3.28 kg to58.32 kg per m2. A total of 25,941 kg of wet biomass of biofouling was estimated to be present on the hull of the Steel Mariner at the time of the survey. Moreover, an estimated total of 1,397 kg of the Didemnum was also present on the barge and a further 460 kg was present on the seabed within an approximate 80 x 40 m area surrounding the barge. Two North Island species that do not occur in the South Island, the ribbed slipper limpet Crepidula costata

and the red alga Cladhymenia lyallii, were also found amongst the extensive biofouling. The abundance of the ribbed slipper limpet was found to be as high as 560 individuals per 0.25 m2. Both species were also noted surviving on the seabed underneath the Steel Mariner. It appeared the presence of the Didemnum and the two aforementioned species on the seabed had come about as a result of them being naturally de-fouled from hull of the Steel Mariner

during the barges’ ‘to and fro’ movements during windy conditions.

The history of the Steel MarinerThe Steel Mariner (formally known as the Intermac 256) is a 2,651 gross weight tonnes (GWT), 72 x 21.6 x 4.17 m dumb deck barge built in Australia in 1969. The Steel Mariner is believed to have arrived in New Zealand from the Philippines prior to 1991. The barge has largely been unemployed and has only moved five times in its 12-yearhistory in New Zealand (Figs. 2a and b). The barge was initially employed at an oil rig off Taranaki, North Island, before it was damaged on 16 March 1992 (Fig. 2a). The Steel Mariner was then towed to Nelson and purchased in a damaged condition by David Brown Construction Ltd and subsequently towed to Tauranga for repairs in May 1992.Repairs were undertaken by John Dennis of the Gemini Barge Company Ltd, however the cost of the repair work was not paid. As a consequence the barge remained under arrest in Tauranga Harbour, until 8 May 1998 where it was refloated and berthed alongside a wharf, where preparations were completed for a tow to Auckland (Fig. 2a).The Steel Mariner left Tauranga on 12 May 1998 and was anchored west of Rangitoto Island in the Hauraki Gulf, Auckland. Apparently Mr. Dennis secured the ownership of the Steel Mariner from David Brown Construction Ltd in compensation for the unpaid repair work. Sometime in the middle of 2000, Heli Harvest Ltd, a helicopter forest harvesting company based in Auckland, successfully negotiated a lease to use the Steel Mariner as a landing platform for harvesting logs in remote areas of the Marlborough Sounds. In late June 2000, the Steel Mariner was towed back to Tauranga for some necessary structural modifications in preparation for her logging work in the Marlborough Sounds (Fig. 2b). The Steel Mariner spent around seven months berthed next to the Tauranga bridge marina while undergoing structural modifications. The barge left Tauranga for the Marlborough Sounds in late January 2001 (Fig. 2b). Owing to a drop in log export prices logging operations have been put on hold, hence the barge has remained west of Kaipupu Point, Picton since her arrival (Fig. 1).

The discovery of a mysterious sea squirt in Whangamata HarbourInterestingly, in October 2001, the Whangamata Harbour Master noticed a colonial ascidian dominating wharf piles in Whangamata Harbour (Coromandel Peninsula, North Island) (Fig. 2a). Environment Waikato immediately commissioned marine scientist Dr. Brian Coffey, to identify and describe the distribution and pest potential of the organism. The ascidian was identified as a Didemnum species and Dr. Coffey advised that the species posed aserious biosecurity threat to the New Zealand Greenshell™ mussel aquaculture industry given its preference for artificial structures and smothering capabilities (Coffey, 2002). Interestingly, Dr. Coffey, along with taxonomists at Te Papa Museum and at the National Institute of Water and Atmospheric Research (NIWA), had never witnessed this particular Didemnum species in New Zealand waters before (B. Coffey, pers. comm.).

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Figure 1. Location of the Steel Mariner moored west of Kaipupu Point, Picton, New Zealand.

Figure 2. A, the voyage history of the Steel Mariner in New Zealand between 1991 and 1998 and B, the voyage history of the Steel Mariner in New Zealand between 2000 and 2003.

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MFish subsequently contracted Dr Coffey to send samples to two world authorities on ascidian taxonomy: Dr. Patricia Mather (Queensland Museum, Australia) and Dr. Gretchen Lambert (Californian State University, Department of Biological Sciences, Fullerton, California). While both taxonomists agreed that the ascidian was a species of Didemnum, their views on its origin differed. For instance, Dr Mather believed the ascidian was not recognizable as any of the more than 100 species of the genus known from Australia and Indo-West Pacific waters, or as any described species from elsewhere in the world (Mather, 2002). Dr. Mather reported that the undescribed Didemnum is likely to be an indigenous species of New Zealand that has had an extraordinary season due to favorable environmental conditions (Mather, 2002).

Alternatively, Dr. Lambert believed the Didemnum was undoubtedly not indigenous to New Zealand because the species appears to be identical to one recently discovered in the northeast United States and Canada, which is continuing to spread. She suggests that the species might be of Japanese origin, however supporting evidence is still being sorted out (G. Lambert, pers. comm .). Based on the evidence supplied by the two taxonomists, MFish believethe species is most likely to be native species of New Zealand that has an extraordinary season due to favorable environmental conditions. The ascidian was later described and labeled Didemnum vexillum in February 2002 (Kott, 2002).

Distribution of Didemnum vexillum in New Zealand

The Chief Technical Officer for MFish Marine Biosecurity contracted NIWA to collect and DNA sequence specimens of D. vexillum look-alikes from the hull of the Steel Mariner, the seabed below, and from the surrounding Marlborough Sounds. DNA sequencing of the 18S rRNA gene revealed that the Didemnum sp. on the Steel Mariner

and seabed below were the only samples that matched those in Whangamata Harbour (i.e. D. vexillum) (Page & Webb, 2002). Baseline surveys of ports around New Zealand undertaken in 2001/02 by NIWA revealed that similar looking species to D. vexillum have been found in Tauranga, Wellington, and Nelson (Fig. 2). Further delimitation surveys of the Shakespeare Bay area between January and July 2002 revealed that D. vexillum had successfully colonized a neighboring barge, the Waimarie I (Coutts, 2002b). Considering this vessel is an active barge that has visited the north Island of New Zealand on several occasions, including mussel farms throughout the Marlborough Sounds, the potential for this species to be rapidly spread via mobile artificial structures is clearly demonstrated. On-going inspections of Greenshell™ mussel lines in the Marlborough Sounds have yet to detect D. vexillum.

Stakeholder meeting and trial eradication

A group of stakeholders met on 16 July 2002 to discuss management options for reducing the species spread. The consensus was a trial for the use of an underwater vacuum device to remove the bulk of D. vexillum from the hulls of the Steel Mariner and Waimarie 1 , and the seafloor below. Both barges would then be towed to the mouth of a nearby river to kill the remaining D. vexillum colonies given the species intolerance to salinities below 25 ppt (G. Lambert, pers. comm .).

In late July 2002, New Zealand Diving and Salvage Ltd (NZDS) in Wellington was commissioned by MFish to design, test, and document the efficacy of an underwater vacuum and filtering system for the removal of the bulk of the D. vexillum from the two barges and seabed. The divers completed vacuuming the bulk (approximately 473 kgs) of the D. vexillum, as well as other biofouling organisms from the hull of the Steel Mariner in just two days (2-3 August 2002). A post-vacuuming quantitative survey revealed that the vacuuming operation removed an estimated 80% of the original D. vexillum wet biomass weight (Coutts, 2002c). Approximately 200 g of D. vexillum

was also hand-scraped from the hull of the Waimarie 1 . Vacuuming attempts to collect colonies on the seabed below the Steel Mariner proved to be inefficient and were abandoned after two days (Coutts, 2002c). Both barges were not towed to the mouth of a nearby river as planned because the local Harbour Master believed they would be a navigational hazard, hence they remained at their original location.

Further spread

On 13 August 2002, an additional survey revealed that D. vexillum had spread to the Waimahara wharf, some 500 m around the corner from the Steel Mariner (Fig. 1). A total of 70 (40 %) of the 173 available wharf piles had been infected with the species (Coutts, 2002b). Some piles possessed coverage of up to 95% from the waterline to the seabed (i.e. 16 m). Furthermore, percentage cover estimates were greatest amongst piles closest to the Steel Mariner

indicting the source of inoculation probably originated from colonies on the Steel Mariner.Discussion

The on-going surveillance efforts of Shakespeare Bay by Cawthron Institute for NIMS have proven worthwhile given the detection of D. vexillum on the Steel Mariner. The Steel Mariner was targeted because from the author’s

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experience, vessels poorly maintained above the waterline are a good indication that the submerged area of the hull is also in poor condition. This is because during dry-docking, most large vessels refurbish the areas above the waterline, while their submerged hull is being anti-fouled. Therefore, given that the above waterline portion of the hull was poorly maintained, this indicated that the vessel had not been dry-docked for some considerable time, the anti-fouling paint would be spent and extensive biofouling communities could be present. Not surprisingly the vessel has not been dry-docked since its arrival in New Zealand prior to 1991 and a total of 25,941 kg of wet biomass of biofouling was estimated to be present on the hull of the Steel Mariner at the time of the survey.Interestingly, given the size and dimensions of the barge, it is too large for any of New Zealand’s dry-docks.Therefore, serious considerations should be given in future to vessels that intend to immigrate to destinations where they cannot be adequately maintained.

The origin and management of Didemnum vexillum

The Steel Mariner never visited Whangamata Harbour; only Nelson, Tauranga and Auckland. While D. vexillum

look-alikes have been found in Nelson and Tauranga, they have not yet been DNA sequenced and matched with the Whangamata Harbour D. vexillum. If DNA sequencing shows that the D. vexillum also occurs in Nelson, then there is a possibility that the Steel Mariner may have been colonized by D. vexillum in Nelson and the barge subsequently transported it to Tauranga as early as 1992. Dr. Coffey, who was originally commissioned by Environment Waikato to identify and assess the pest potential of D. vexillum in Whangamata Harbour, believes he has observed D.

vexillum on wharf piles at the Tauranga bridge marina (B. Coffey, pers. comm.). Therefore, given that the Steel

Mariner was berthed next to the marina for seven months (June 2000 to January 2001) while undergoing structural modifications in preparation for the logging work in the Marlborough Sounds, it is most likely that the Steel Mariner

was infected by D. vexillum at this location and survived the week long voyage at < 5 knots to the Marlborough Sounds.

Interestingly, D. vexillum was first detected in Whangamata Harbour in October 2001. Considering the Steel

Mariner was most likely colonized in Tauranga Harbour between June 2000 and January 2001, it is possible that D.

vexillum may have been introduced to New Zealand via the hull of a foreign vessel to Tauranga Harbour first, and then translocated to Whangamata Harbour by a pleasure boat or fishing vessel thereafter. MFish have requested samples of the Didemnum species from Connecticut, United States, to undertake genetic analysis to confirm whether it is the same species as the one from Whangamata Harbour. These samples will undergo DNA sequence analysis and confirm whether the Didemnum species in the United States is D. vexillum. This will move the process one step closer to identifying the species’ origin but like many marine species, its true origin may never be confirmed.Therefore, the species should be classified as cryptogenic (i.e. origin unknown) until its true origin is confirmed, and a precautionary approach adopted towards its management.

Despite the on-going debate over the species origin, D. vexillum is still considered by some stakeholders as an undesirable species that should be managed. However, as a consequence of MFish declaring it as a native species of New Zealand, the responsibility for managing the species lies with the Marlborough District Council (MDC) or local council. Owing to a lack of experience and finances, the MDC are reluctant to take any action, hence little has been done about managing the spread of the species. MFish chose to fund the vacuuming operation to remove the bulk of D. vexillum because they saw it as an opportunity to design, test, and document the efficacy of an underwater vacuum system and filtering system that could have a variety of useful applications as an incursion response tool.

Potential spread of Didemnum vexillum

Owing to the Steel Mariner remaining west of Kaipupu Point for close to two years, D. vexillum had the potential to undergo at least two reproductive cycles. Therefore, it is not surprising that the species spread to the Waimarie 1

barge and Waimahara wharf piles. Considering there are limited currents and artificial structures in the area (which the species appears to prefer), the species is not expected to naturally spread beyond Shakespeare Bay. This is because Didemnum larvae are known only to disperse from a few minutes to a few hours before settling (Morgan, 1995; Mather, 2002; G. Lambert, pers. comm.). Interestingly, Lambert (2001) states that introduced ascidians that persist and flourish usually remain restricted to harbours, even many years after their introduction. Therefore, the species is most likely to spread via human-mediated vectors to mussel farms such as slow-moving vessels. Considering D. vexillum at this point in time appears to be confined to the Steel Mariner, Waimarie I, the area immediate below the barges, and 70 of the Waimahara wharf piles, the opportunity may now exist to successfully eradicate the species from the area. This attempt would need to be undertaken before late winter, early spring, as this is the time that the species is most likely to sexually reproduce.

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Biosecurity risks of towed vessels

Slow-moving towed vessels have been documented as being a serious biosecurity threat for some years. Foster & Willan (1979), for instance, documented the survival of 12 barnacle species on the hull of the oil platform Maui after it was towed from Japan to New Zealand in 1975. DeFelice (1999) recorded 20 exotic biofouling organisms on the hull of the floating dry dock USS Machinist, which was towed from Subic Bay, Philippines, to Pearl Harbour, Hawai‘i, in May 1992. More recently, Apte et al. (2000) documented the successful translocation of the smooth shelled blue mussel Mytilus galloprovincialis from the hull of the USS Missouri to a submarine ballast tank in Pearl Harbour, after it was towed from Bremerton, Puget Sound, in the northwestern United States. In light of these events, including the results of this paper, the biosecurity risks of biofouling on towed vessels could be significantly underestimated. As far as the author is aware, no studies have quantified the biosecurity risk of such vessels. To this end, Cawthron Institute is currently investigating the en route survivorship of biofouling organisms on various vessel types at different hull locations.

AcknowledgementsFirstly, thank you to Qwilton and Grant Biel, Heli Harvest Ltd for their cooperation and support for granting us permission to undertake a survey of the Steel Mariner. Secondly, I wish to thank the following Cawthron staff; Barrie Forrest, Kathryn Blakemore, Kevin Heasman and Rod Asher, who assisted with data collection for this report. I also wish to thank the following people for their invaluable assistance with determining the movements of the Steel Mariner and other barges since their arrival in New Zealand including: Qwilton and Grant Biel, John Dennis (Gemini Barge Company Ltd), Michael Pryce (New Zealand Marine News), Michael Donavon (MONEÕ Associates, Tauranga), Dr Brian Coffey (Brian Coffey and Associates Ltd), Andrew Campbell (The Bay Times Newspaper, Tauranga), Peter McManaway (McManaway Marine Ltd) and Dick Mogridge (Sea-Tow Marine/Fleet Superintendent).

Thank you to Dr Patricia Mather (Queensland Museum, Australia), Dr Gretchen Lambert (Californian State University, Department of Biological Sciences, Fullerton, California) and Heather A. Fried (Graduate Student at the University of Connecticut, Department of Ecology and Evolutionary Biology) for on-going assistance with attempts to ascertain the origin of D. vexillum in New Zealand. Thank you to Chris O’Brien (Ministry of Fisheries, Chief Technical Officer, Marine Biosecurity) for his support throughout this study. Useful comments on the manuscript were provided by Barrie Forrest (Cawthron) and Chad Hewitt (Ministry of Fisheries). This research was funded by the New Zealand Foundation for Research, Science and Technology (FRST).

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transfer of non-indigenous species via a potentially unsuitable environment. Biological Invasions. 2: 75-79.Biosecurity Council. 2003. Protect new zealand: The biosecurity strategy for New Zealand. Prepared by the

Biosecurity Council, August 2003. 63 pp.Coffey, B. 2001. Potentially invasive compound ascidian – Whangamata Harbour – Progress Report No. 1 .

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vessels visiting northern Tasmania. Unpublished MSc. thesis, Australian Maritime College, Launceston, Australia. 283 pp.

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— — —. 2002c. The development of incursion response tools - underwater vacuum and filtering system trials.Cawthron Report No. 755 for New Zealand Diving and Salvage Limited, Wellington, August, 2002.

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DeFelice, R. C. 1999. Fouling marine invertebrates on the floating dry dock USS Machinist in Pearl Harbour to its

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Field, D. 1999. Disaster averted? Black striped mussel outbreak in northern Australia. Fish Farming International

26: 30-31.Foster, B. A. & R. C. Willan. 1979 Foreign barnacles transported to New Zealand on an oil platform. New Zealand

Journal Marine Freshwater Research. 13: 143-149.

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Godwin, L. S. & L. G. Eldredge. 2001. South Oahu marine invasions shipping study (SOMISS). Hawaii Biological Survey, Bishop Museum, Honolulu, Hawaii, Technical Report No. 20.

_ _ _, 2003. Hull fouling of maritime vessels as a pathway for marine species invasions to the Hawaiian Islands. Biofouling 19 (Supplement): 123-131.

Gollasch, S. 2002. The importance of ship hull fouling as a vector of species introductions into the North Sea. Biofouling 18(2): 105-121.

Hay, C.H. 1990. The dispersal of Undaria pinnatifida by coastal shipping in New Zealand, and implications for further dispersal of Undaria to France. British Phycological Journal. 25: 329-313.

– – – & T. Dodgshun. 1997. Ecosystem transplant? The case of the Yefim Gorbenko. Seafood New Zealand, May 1997, pp. 13-14.

Hewitt, C. L. 2002. The distribution and biodiversity of tropical Australian marine bioinvasions. Pacific Science

56(2): 213-222.James, P. & B. Hayden. 2000. The potential for the introduction of exotic species by vessel hull fouling: A

preliminary study . NIWA Technical Report No. 16.Kott, P. 2002. A complex didemnid ascidian from Whangamata, New Zealand. Journal of Marine Biology

Association United Kingdom 82: 625-628.Lambert, G. 2001. A global overview of ascidian introductions and their possible impact on the endemic fauna. In:

Sawada, H.; Yokosawa, H.; Lamb ert, C.C. eds. The Biology of Ascidians. Springer-Verlag, Hong Kong. 249-257.

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Morgan, S.G. 1995. The timing of larval release. In : McEdward, L. ed. Ecology of marine invertebrate larvae. CRC Press. 157-191.

Page, M. & V. Webb. 2002. Collection, DNA sequencing and species verification of Didemnum sp. from Picton

Harbour and surrounding environment. National Institute of Water and Atmospheric Research Report ZBS2001/08B.

Rainer, S. 1995. Potential for the introduction and translocation of exotic species by hull fouling: A preliminary

assessment No. 1 . CRIMP Technical Report No. 1.Schultz, M. & G. W. Swain. 2000. The influence of biofilms on skin friction drag. Biofouling 15 (1-3). 129-139.Thresher, R. E., C. L. Hewitt, & M. L. Campbell. 1999. Synthesis: Introduced and cryptogenic species in Port

Phillip Bay. In: Hewitt, C.L., Campbell, M.L., Thresher, R.E, & Martin, R.B. eds. Marine biological

invasions of Port Phillip Bay, Victoria . Centre for Research on Introduced Marine Pests. Technical ReportNo. 20: 283-295.

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Hull Fouling as a Mechanism for Marine Invasive Species Introductions.Proceedings of a Workshop on Current Issues and Potential Management Strategies

February 12-13 2003. Honolulu, Hawaii. Edited by L.S. Godwin.

Managing Marine Biosecurity in New Zealand: From a Research Provider’s Perspective

ASHLEY D. M. COUTTS1

Marine Biosecurity Section, Cawthron Institute, Private Bag 2, Nelson, New Zealand. Tel. (+64) 3 548 2319, Fax. (+64) 3 546 9464,

E-Mail: ashley.coutts@cawthron.org.nz

(1 Mr Coutts is not a member of the New Zealand Government nor do his views necessarily reflect the directions, policies or intentions of the New Zealand Government or the Ministry of Fisheries.)

Abstract

New Zealand’s isolation has given rise to a high level of endemic biodiversity that is of great value to the quality of life of New Zealand’s citizens and their sense of identity as a nation. Furthermore, this unique endemism makes a significant contribution to global biodiversity and places an important obligation on New Zealanders to ensure its continued existence. However, this legacy of New Zealand’s evolutionary isolation is particularly vulnerable to the increasing pressure from the introduction of marine pests because of the countries reliance on shipping for trade. Recognizing the need to protect New Zealand from future incursions of marine pests, the New Zealand government has allocated $NZ9.8 million over five years (2000–2005) to aid the development of information and management systems to enhance New Zealand’s marine biosecurity. The New Zealand Ministry of Fisheries is responsible for managing marine biosecurity in New Zealand and essentially focuses on preventing introductions of marine species, because eradicating or managing pests is extremely difficult once theybecome established. Accordingly, most effort is directed towards pre-border and border controls, and towards the greatest risks, which at this point in time are ballast water and biofouling.

IntroductionNew Zealand’s evolutionary isolation has given rise to a high level of endemic biodiversity that is of great value to the quality of life of New Zealand’s citizens and their sense of identity as a nation. Estimates suggest that up to 80% of New Zealand’s indigenous biodiversity occurs in the sea (i.e. 95% sponges; 90% mollusks; 60% bryozoans and crabs; 35% macroalgae; 20% of fish) (Towns & Ballantine, 1993; Myres, 1997). Furthermore, this unique endemism makes a significant contribution to global biodiversity and places an important obligation on New Zealanders to ensure its continued existence.

While New Zealand’s isolation provides a natural defense against the arrival of many serious marine pests and a unique ability to control the borders, such isolated islands that contain a large proportion of endemic species are also considered vulnerable to incursions by non-indigenous species (MacArthur & Wilson, 1967; Ruiz et al.,1997). New Zealand is particularly vulnerable to pest introductions via shipping because of its reliance on international shipping for trade (i.e. approximately 95% of the countries exports by value travel by ship and five times more is exported than is imported).

It is therefore not surprising that at least 148 non-indigenous marine species (NIMS) are known to have been either deliberately or accidentally introduced to New Zealand (Cranfield et al., 1998). Fortunately only a small percentage of these are considered pests (e.g. the Pacific oyster Crassostrea gigas; the polychaete Ficopomatus

enigmaticus; the Asian date mussel Musculista senhousia; the Asian kelp Undaria pinnatifida ; the swimming crab Charybdis japonica; the sea squirt Ciona intestinalis). However, there remains a clear and present threat of some of the world’s most renowned marine pests (e.g. the European green crab Carcinus maenas; the northern Pacific seastar Asterias amurensis; the Mediterranean fanworm Sabella spallanzanii ; the green seaweed Caulerpa taxifolia)establishing in New Zealand given their presence in Australia.

Recognizing the need to protect New Zealand from future incursions of NIMS, the New Zealand government announced that $NZ9.8 million would be spent over five years (2000–2005) to develop information and management systems to enhance New Zealand’s marine biosecurity. The word “Biosecurity” refers to – “the exclusion, eradication or effective management of risks posed by pests and diseases to the economy, environment and human health” (Biosecurity Council, 2003). The purpose of this paper is to outline from a research provider’s perspective how the New Zealand government, specifically the New Zealand Ministry of Fisheries (MFish), presently manages marine biosecurity.

Legislative EnvironmentNew Zealand is party to many international multilateral agreements aimed at reducing the risk of importing/exporting marine pests (Table 1). While these agreements are binding on the government of New Zealand,

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they do not impose obligations on individual citizens, except in so far as they are implemented into the laws of New Zealand. The domestic laws that are most relevant to meeting New Zealand’s international biosecurity obligations are the Biosecurity Act 1993 (BSA), the Resource Management Act 1991 (RMA) and to a lesser extent, the Local Government Act 1971 and the Maritime Transport Act 1994.

Table 1. Examples of some of the international multilateral agreements recognized by the New Zealand government.

• The 1992 Earth Summit

• Agenda 21 (i.e. considering the adoption of appropriate

rules on ballast water discharge).

• The Convention on Biological Diversity 1992 (CBD).

• The UN Convention on the Law of the Sea 1982

(UNCLOS).

• The Basel Convention on the Control of Trans -boundary

Movements of Hazardous Wastes and their Disposal.

• Convention on the Prevention of Marine Pollution by

Dumping of Wastes and other Matter 1971 (London Dumping

Convention).

• The International Convention for the Prevention of

Pollution from Ships 1973 (MARPOL).

• International Maritime Organisation (IMO) (i.e. ballast

water management).

• The Convention for the Protection of the National

Resources and Environment of the South Pacific Region 1986

(SPREP).

The Biosecurity Act 1991 (BSA)The BSA is the main legislation used to achieve biosecurity objectives i.e. exclusion, eradication and effective management of pests and “unwanted species” (see definition below) in New Zealand. The BSA is designed to provide 3 levels of response to biosecurity threats – national, regional and individual responses. The BSA is an empowering act rather than prescriptive, enabling various bodies to treat, destroy and take steps to prevent the spread of any pest or “unwanted organism”. An “unwanted organism” refers to any organism that a Chief Technical Officer (CTO) for Biosecurity believes is capable or potentially capable of causing unwanted harm to any natural and physical resources or human health.

The Resource Management Act 1991 (RMA)As far as marine biosecurity is concerned, the RMA provides for the management of natural resources and effects on the environment of New Zealand’s land, air and sea, within the “Coastal Marine Area” (CMA). The CMA includes the foreshore, seabed, coastal water and the airspace above the water out to the outer limit of the territorial sea (i.e.

within 12 nautical miles off New Zealand’s shoreline) and does not apply within New Zealand’s Exclusive Economic Zone (i.e. the sea beyond the territorial sea out to the 200 mile limit).

Operating EnvironmentMFish is the lead government agency responsible for managing marine biosecurity in New Zealand. MFish’s primary biosecurity responsibilities in the marine environment are to: 1) develop policy on all aspects of the marine biosecurity system, such as border/vector measures, 2) undertake surveillance, 3) lead incursion responses, and 4) identify and contract appropriate research. MFish is assisted by other New Zealand government departments such as the Ministry of Agriculture and Forestry, Department of Conservation and the Ministry of Health. MFish manages marine biosecurity in the operating environment in three main areas: 1) Pre -border (preventing entry); 2) Border controls (detection and interception); and 3) Post-border controls (eradication/control).

MFish focuses on preventing introductions of marine pests, because eradicating or managing pests has proven to be extremely difficult and costly once they become established. In particular, MFish has publicized 6 “unwanted” marine species that could cause serious problems if they were introduced to New Zealand and has surveillance in place for these organisms (i.e. the Mediterranean fanworm Sabella spallanzanii; the European green crab Carcinus maenas; the Chinese mitten crab Eriochier sinensis; the northern Pacific seastar Asterias amurensis;

38

the Asian clam Potamocorbula amurensis; the Green aquarium seaweed Caulerpa taxifola). Effort is largely focused on pre-border and border controls, and towards the internationally agreed greatest risks, which are currently ballast water and biofouling.

Pre-border ControlsPre-border controls consist of measures taken to prevent “unwanted” NIMS entering New Zealand (e.g. restrictions on pathways of species transfer).

Ballast water

The impact of organisms contained in ballast water on New Zealand’s marine environment is potentially highly significant. While New Zealand’s marine environment is considered relatively free of marine pest species and diseases, this could easily change given the countries reliance on international shipping. Therefore, the easiest method to prevent the introduction of NIMS in ballast water is to avoid discharging ballast in New Zealand’sterritorial seas. In May 1998, voluntary guidelines for ballast water were replaced with an Import Health Standard (IHS) enforceable under the BSA. Under the IHS, ballast water loaded within the territorial waters of a foreign country cannot be discharged into New Zealand waters without the permission of a Quarantine Officer. Permission to discharge ballast water will only be granted if: 1) the ballast water has been exchanged en route to New Zealand in areas free from coastal influences, preferably on the high seas, 2) the ballast water is fresh water, or 3) the weather conditions on the voyage in combination with the construction of the vessel have precluded safe ballast water exchange. Emergency discharge is permitted as ship and crew safety is paramount. On average, 1 vessel every 6 months is refused permission to discharge its ballast in New Zealand waters (Biosecurity Council, 2003).

The IHS has also identified 2 regions; Tasmania, Australia and Port Phillip Bay, Victoria, Australia; referredto as Annex 1 regions that are considered ‘higher risk areas’ due to the presence of A. amurensis (Fig. 1). For this reason, ballast water loaded in these 2 areas may not be discharged into New Zealand waters under any circumstance. Providing incorrect information to an inspector or authorized persons is an offence under the BSA and carries a penalty for individuals of up to 12 months imprisonment and/or a fine not exceeding NZ$50,000, and for corporations a fine not exceeding NZ$100,000.

Biofouling

At present there are no regulations mandating vessel hull hygiene. However, on 30 May 1994, a New Zealand Fishing Company chartered a Russian Bartm Class super trawler; the F.V. Yefim Gorbenko; which arrived in New Zealand from the Black Sea with approximately 90 t of NIMS on its hull (Hay & Dodgshun, 1997). This event prompted the New Zealand Fishing Industry to develop a ‘Code of Practice’ in December 1996 requesting that all chartered foreign owned or foreign sourced fishing vessels must be substantially free from plant or animal growth prior to entering New Zealand’s EEZ (Pfahlert, 1997). If no such assurance can be given, vessels must be inspected and cleaned before departure. Alternatively, vessels should be inspected in New Zealand and if deemed necessary,biofouling removed in a manner that no foreign organisms enter the marine environment.

Border ControlsBorder controls consist of measures taken to prevent unwanted NIMS reaching native ecosystems (e.g. domestic or internal quarantine).

Surveillance

Surveillance plays an integral part of pest control. Successful eradication and control programs for “unwanted” species depend on their early detection while their distribution and abundance is small (Moody & Mack, 1998; Culver & Kuris, 2000; Field, 1999; Clout & Veitch, 2002). MFish has contracted the National Institute of Water and Atmospheric Research (NIWA) to develop a national surveillance program for marine pests. The program consists of 2 major areas: 1) baseline surveys of shipping ports and high-risk points of entry, and 2) surveillance for high-risk marine pests.

39

130 °E 150 °E 170 °E

40 °S

20°S

Port Phillip

Bay

Australia

Figure 1. Justification of Annex 1 regions for ballast water exchange.

NIWA is undertaking comprehensive baseline surveys of the marine organisms that are present in 13 of New Zealand’s shipping ports and main points of entry for international yachts and launches (see Floerl et al., in these proceedings). The surveys use an internationally accepted standard and will identify the range of marine species,their origins and distribution in New Zealand ports and will form a baseline for future monitoring of port environments in New Zealand. Furthermore, this information will also provide a basis for international risk profiling of “unwanted species” through the sharing of information with other shipping nations.

In addition to the port surveys, NIWA is continually developing more targeted surveillance for the 6 “unwanted species” stated previously, based on a risk assessment approach. This surveillance is focusing on 8 ports (i.e. Whangarei; Waitemata; Tauranga; Wellington; Nelson; Lyttelton; Otago; Bluff) (see Floerl et al. in these proceedings) that have been identified as being high-risk locations for the arrival of NIMS based on their past history of invasion, current international shipping movements, the variety of habitats available, and restricted exchange of water with oceanic environments (Inglis, 2001, in press). MFish is also establishing a public surveillance network via the distribution of pamphlet and posters to clubs, shops, councils, associations, researchers and agencies associated with the marine environment. Furthermore, a toll free Marine Invaders Hotline has been established by MFish for anyone who finds or suspects the presence of an exotic organism (i.e. 0800 INVADERS [0800 468 233] or e-mail biosecurity@fish.govt.nz).

Proposed hull cleaning regulations

The release of de-fouled material back into the marine environment, particularly from foreign vessels is a serious marine biosecurity risk. MFish is considering regulations under the BSA to minimize the biosecurity risk from hull cleaning activities by controlling the release of de-fouled material from vessel hulls into the coastal environment. The proposed regulations will require cleaning facilities (i.e. dry-docks; travel lifts; floating docks; slipways; sealifts; boat repair yards; hardstands; cradles; rails) to collect and contain all de-fouled material and treat any

Distribution of A. amurensis

Shipping routes

Adelaide

Brisbane

Sydney

Tasmania

New Zealand

40

discharge prior to its entering the marine environment. In-water cleaning of vessel hulls (by divers or using remotely operated vehicles) is also considered. MFish is considering three options to manage hull cleaning: 1) prohibit in-water cleaning, 2) regulations targeted at higher risk vessel only, and 3) guidelines/Code of Practice for hull cleaning facilities and diver services. MFish also promotes maintenance of 'clean' hulls through public education on the use of effective anti-fouling paints, their correct application and the need for frequent cleaning of the initial slime layer so that biofouling does not develop between regular (e.g. annual) slipping of vessels for cleaning and anti-fouling.

Post-Border ControlsPost-border controls consist of measures used to manage the impacts of species that have escaped into native environments (e.g. eradication; maintenance controls).

Incursion Response

Eradication of NIMS is typically very difficult, largely because there are few tried and proven methods that are capable of effectively combating species in the marine environment. MFish are gradually building an incursion response 'toolbox' (i.e. Incursion Response Options and Systems) to assist with the success of any future control or eradication attempts (see Stuart, 2002; Bax et al., 2003). The CTO for Marine Biosecurity at MFish is responsible for driving the initial response to new incursions in the marine environment, although the organisation does not have field staff it can deploy for this purpose. Therefore, MFish is reliant on private contractors to undertake anyincursion response. MFish have a proposed “Marine Biosecurity Incursion Response Protocol” that has yet to be confirmed.

Containment and Pest Management

If an incursion response is unsuccessful or a marine pest is detected too late (i.e. the species is well established and wide-spread), a national or regional pest management strategy can be implemented by MFish and/or regional councils. However, in order for this to occur the CTO, MFish must deem the species an “unwanted organism” under the BSA. For exa mple, in January 2002, MFish implemented a Framework focusing on a vector management program to reduce the spread of the invasive seaweed U. pinnatifida around New Zealand. The programme primarily focuses on vessel and marine farming vectors of U. pinnatifida and will run until June 2004.

ResearchMuch of the research has concentrated on the risks posed by ballast water (i.e. determining which species are surviving in the ballast water; determining the effectiveness of ballast water exchange to reduce the number of organisms arriving in New Zealand; establishing suitable areas for ballast water exchange). Researchers are also attempting to predict which marine pests are likely to reach New Zealand, and of these, which are likely to spread rapidly and become pests.

The FutureDespite New Zealand possessing what might appear to be an effective marine biosecurity management system, the country’s national biological assets are under increasing pressure from NIMS as New Zealand increases its trading relationships with other countries. Fortunately the New Zealand Biosecurity Council is in the process of developing a ‘Biosecurity Strategy for protecting New Zealand’, which will identify any shortfalls in New Zealand’s ability to manage biosecurity. This strategy should be available by August 2003.

AcknowledgementsWe would like to acknowledge the New Zealand Foundation for Research, Science and Technology (FRST) for funding the development of this paper.

Literature Cited

Bax, N. K. Hayes, A. Marshall, D. Parry & R. Thresher. 2002. Man-made marinas as sheltered islands for alien marine organism: Establishment and eradication of an alien invasive marine species. In: Veitch, C. R. & Clout, M. N. eds. Turning the tide: the eradication of invasive species. IUCN SSC Invasive Species Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK. 26-39.

Biosecurity Council. 2003. Protect New Zealand: The biosecurity strategy for New Zealand. Prepared by the Biosecurity Council, August 2003. 63 pp.

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Clout, M. N. & C. R. Veitch. 2002. Turning the tide of biological invasions: the potential for eradicating invasive species. In: Veitch, C. R. & Clout, M. N. eds. Turning the Tide: Tthe eradication of invasive species.Proceedings of the International Conference on eradication of island invasives. The World Conservation Union. No 27.

Cranfield H.J., D.P. Gordon, R.C. Willan, B.A. Marshall, C.N. Battershill, M.P. Francis, W.A. Nelson, C.J.

Glasby & G.B. Read. 1998. Adventive marine species in New Zealand. National Institute of Water and Atmospheric Research, Technical Report 34. Wellington, New Zealand. 48 pages.

Culver, C. S. & A. M. Kuris. 2000. The apparent eradication of a locally established introduced marine pest. Biological Invasions 2: 245-253.

Field, D. 1999. Disaster averted? Black striped mussel outbreak in northern Australia. Fish Farming International

26: 30-31.Hay, C. H. & T. Dodgshun. 1997. Ecosystem transplant? The case of the Yefim Gorbenko. Seafood New Zealand,

May 1997, 13-14.Inglis G.J. 2001. Criteria for selecting New Zealand ports and other points of entry that have a high risk of invasion

by new exotic marine organisms. Report for Ministry of Fisheries Research Project ZBS2000/04. National Institute of Water and Atmospheric Research, Christchurch, New Zealand. 27 pages.

MacArthur, R. H. & E. O. Wilson (eds.). 1967. The Theory of Island Biogeography. Princeton University Press, Princeton, N.J. 203 pp.

Moody, M. E. & R. N. Mack. 1988. Controlling the spread of plant invasions: the importance of nascent foci. Journal of Applied Ecology 25: 1009-1021.

Myres, A. A. 1997. Biogeographic barriers and the development of marine biodiversity. Estuarine, Coastal and

Shelf Science 44: 241-248.Pfahlert, J. 1997. Avioding hull contamination of the New Zealand environment by fishing boats. Seafood New

Zealand. 5 (May): 15. Ruiz, G. M. J. T. Carlton, E. D. Grosholz & A. H. Hines. 1997. Global invasions of marine and estuarine habitats

by non-indigenous species: mechanisms, extent, and consequences. American Zoologist 37: 621-632.Towns, D. R. & W. J. Ballantine. 1993. Conservation and restoration of New Zealand island ecosystems. Trends

in Ecology and Evolution 8: 452-457.

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Hull Fouling as a Mechanism for Marine Invasive Species Introductions.Proceedings of a Workshop on Current Issues and Potential Management Strategies February 12-13, 2003. Honolulu, Hawaii. Edited by L.S. Godwin.

Current research in marine biosecurity undertaken by the National Institute of Water

and Atmospheric Research, New Zealand

OLIVER F LOERL, GRAEME INGLIS, NICK GUST, BARBARA HAYDEN, ISLA FITRIDGE AND GRAHAM FENWICK

National Centre of Marine Biodiversity and Biosecurity, National Institute of Water and Atmospheric Research, P.O. Box 8602,

Christchurch, New Zealand; Email: O.Floerl@niwa.co.nz

Abstract

The National Institute of Water and Atmospheric Research (NIWA) is involved in research on marine pests around New Zealand. Its main current research areas are the development and implementation of effective and efficient survey and surveillancetechniques for introduced marine species. These techniques will help to (1) assess the current range and distribution of marine aquatic invasive species around New Zealand, and (2) detect newly established species before they have had an opportunity to spread widely and become abundant.

IntroductionOver the past century, nearly 160 marine nonindigenous species (NIS) have become established in New Zealand’s coastal marine environments at a rate of approximately one every nine months (Cranfield et al. 1998).Being a small island nation, New Zealand is heavily dependent on shipping of commodities. Because of the consequently large number of ships that visit the numerous ports around the country, New Zealand is at a constant risk of new introductions of NIS (Williams, 2000) . Current indications are that the rate of new introductions is accelerating rather than slowing, as the volume of international shipping trade increases and commercial cargo vessels get bigger and faster. For example, it has been estimated that, on any given day, more than 3,000 marine species may be in transit around the world in the ballast water of ships or attached to their hulls (Carlton, 1996). Therefore, the development of preventative measures to avoid new introductions is of uttermost importance to the integrity of the country’s native ecosystems. The National Institute of Water and Atmospheric Research (NIWA) is a Crown Research Institute with research campuses located across both of New Zealand’s main islands, as well as in Australia and the United States (for details see www.niwa.co.nz). Over the past few years, NIWA’s National Centre of Marine Biodiversity and Biosecurity has been actively involved in baseline surveys of New Zealand’s coastal biodiversity and invasion status, and in the development of techniques to identify new introductions before they reach pest status. Much of this research has been funded by the New Zealand Ministry of Fisheries, the main governmental authority for marine biosecurity. In 2004, the responsibility for marine biosecurity in New Zealand was transferred to a new government agency, Biosecurity New Zealand (Ministry of Agriculture and Forestry). In this paper, we provide a brief overview on NIWA’s marine biosecurity research in New Zealand for the period of 2000 - 2004. Our summary is not exhaustive, and restricted to a description of national port surveys and surveillance for target species. It does not include research on biosecurity risks of private pleasure craft, which is covered in a separate article in this volume.

Baseline surveys and target surveillance for marine NISThe chances of controlling or eradicating an outbreak by an exotic species are greatest if the interloper is detected early, before it has had an opportunity to spread widely and become abundant (Moody & Mack, 1 988;Sakai et al., 2001). NIWA is working with the New Zealand Ministry of Fisheries to develop a national surveillance programme for marine pests so that they can be detected soon after their arrival in the country. The programme is funded as part of the government’s comprehensive five-year Biodiversity Strategy package on conservation, environment, fisheries and biosecurity. It consists of two major elements:

(i) Surveys of shipping ports and high-risk points of entry

International shipping is the principal means by which marine species are transported around the world (Ruiz et

al., 1997; Ruiz et al., 2000). Ports and marinas are major hubs of shipping activity and, therefore, particularly important sources of exotic species and sites for their introduction (Hewitt et al., 1999). In 1997, the International Maritime Organisation (IMO) released a set of guidelines (Resolution A868(20)) for ballast water management which, among other things, encouraged states to undertake biological surveys of port environments. NIWA is undertaking comprehensive surveys of the marine organisms that occur in New Zealand’s shipping ports and main points of entry for international yachts and launches. A total of 13 ports and three yachting marinas (Fig. 1) were selected from a larger pool of sites for sampling based on various parameters, including the numbers, types and sizes of international vessels that enter the ports, the number of

43

source countries the vessels originate from and the frequency of visits of vessels from the same source location (Inglis, 2001). The surveys will provide an initial inventory of the range of species (both introduced and native) that are present in New Zealand ports and an indication of how widespread they are within the country. This will form a baseline for future monitoring of port environments in New Zealand and a basis for international risk profiling of problem species through the sharing of information with other shipping nations. A number of other countries, including Australia, United Kingdom, USA, Brazil, India, South Africa, Iran, and Ukraine have also recently implemented port surveys using similar standardized sampling techniques.

In New Zealand, the port surveys are based on protocols developed by CRIMP (Hewitt & Martin, 2001) and incorporate a range of techniques to cover all major habitats and lifestyles of marine organisms in port environments :

• Quadrat sampling of fouling organisms on wharf piles and other hard surfaces; • Video transects and video quadrats of organisms on wharf piles and other hard surfaces;• Visual searches by scuba divers of marine and intertidal habitats within the ports;• Benthic grab samples for soft-sediment fauna;• Epibenthic sled tows to capture large surface-dwelling organisms;• Trapping using four different types of traps, designed to capture starfish, crabs, fishes and small

crustaceans, and• Core samples to detect dinoflagellate cysts.

Between 2001 and 2003, NIWA surveyed all 13 of New Zealand’s major trading ports and three marinas that are the principal points of entry for international yachts and other recreational boats that enter New Zealand. Repeat surveys of some o f these ports will be undertaken in 2004 and 2005.

Figure 1. Commercial shipping ports around New Zealand selected for invasive species surveys. International yachting marinas selected for additional surveys are located around Opua (marina only), Whangarei and Auckland.

44

Table 1. Target species identified by the New Zealand Ministry of Fisheries.

(ii) Surveillance for high-risk marine pests

In addition to the port surveys, NIWA carried out more targeted surveillance for seven species that the New Zealand Ministry of Fisheries had identified as being a significant risk to the native marine environments of New Zealand. Each of these species has a notorious track record of invasion overseas and has caused large ecological and/or economic impacts (Table 1). Only one – the Japanese kelp, Undaria pinnatifida – has become established in the wild in New Zealand, although five of the species are already present in southern Australia.This list of “target species” may eventually be expanded as more information comes to light about the relative risks of other harmful invaders reaching New Zealand waters.

New Zealand has a long history of quarantine and surveillance for agricultural pests (Hackwell & Bertram, 1999; Williams, 2000) but, until now, little consideration has been given to how surveillance programmes should be designed for marine pests. In fact, New Zealand was the first country in the world to develop a national programme of surveillance for unwanted marine species. Planning such a programme is not a trivial issue, as marine ecological surveys are generally time -consuming and expensive. Moreover, initial populations of pest species are likely to be sparse and aggregated (Crooks & Soulé, 1999; Mack et al., 2000),making them easy to miss using conventional marine survey designs. NIWA took a risk-based approach in developing the surveillance programme. The initial focus was on eight harbours (Whangarei, Waitemata, Tauranga, Wellington, Nelson, Lyttelton, Otago, and Bluff; Fig. 1) that had been identified as high-risk on the

The Mediterranean Fanworm, Sabella spallanzani , is a large (up to 40 cm length), tube building poly chaetethat has invaded a number of sheltered harbours and bays in Western Australia, Victoria, Tasmania, New South Wales and South Australia. It has also been recorded from Indonesia (Java) and Brazil (Rio de Janeiro). The fanworm has a rapid growth rate and can form high density beds, displacing other species and fouling boats and other marine structures.The European Green Crab, Carcinus maenas, has been introduced to the Atlantic Coast of USA, California, Washington, southern Australia (Victoria, South Australia, and New South Wales), and South Africa. It is a voracious predator with a broad diet that is able to live in a wide range of estuarine environments. In California, the green crab has been implicated in the decline of native shellfish populations.The Chinese Mitten Crab, Eriochier sinensis , is a catadromous species whose juveniles dig burrows in riverbanks within the brackish and freshwater reaches of estuarine tributaries. Large densities of these burrows can undermine the banks and accelera te erosion. Adult mitten crabs undertake mass migrations into estuarine environments to breed and can occur in such numbers that they can block weirs and fish screens. Adults are alsoknown to carry parasitic lung flukes, which infect humans. The mitten crab has been introduced to northern Europe and San Francisco Bay.The Northern Pacific Seastar , Asterias amurensis, was accidentally introduced into the Derwent River Estuary in Tasmania in the early 1980’s and has since spread to other parts of Tasmania and to Port Phillip Bay, Victoria.Adults are capable of producing millions of offspring and can occur in very large aggregations. They are major predators of shellfish and other molluscs.The Asian Clam, Potamocorbula amurensis, was first found in San Francisco Bay in 1986, but by 1988 had reached average densities of up to 2000 animals per square metre over large areas of the bay. P. amurensis is a filter feeder and the large densities of this bivalve appear to have dramatically altered phytoplankton populations in the upper reaches of the bay. It has also had a major impact on other benthic animals. The Japanese Kelp, Undaria pinnatifida , was discovered in New Zealand in the late 1980’s and has since spread around most of its coastline. It is a la rge (1 -2 m tall) kelp that grows on a range of natural and artificial (e.g. boats, ropes, pontoons, moorings) hard surfaces and can dominate reef assemblages. Despite its rapid geographic spread, in many areas it is still confined to harbour environments and large areas of natural coastline remain uninfested.The Green Aquarium Weed, Caulerpa taxifolia , is a tropical alga native to native throughout many areas of thetropical Pacific and Caribbean. It is a popular aquarium plant, and prolonged breeding in aquaria has thought to have produced a hardier strain that differs from native plants genetically and has a higher tolerance to cold water temperatures. C. taxifolia has been introduced to at least three geographical regions outside its native range: the Mediterranean Sea on the coasts of Croatia, France, Italy, Monaco, and Spain, (2) the southern Californian coast near San Diego, and (3) parts of the coasts of New South Wales and South Australia. It has the capacity to overgrow all other benthic organisms and is causing devastating impacts in large parts of the Mediterranean coast.

45

basis of their past history of invasion, current international shipping movements, the variety of habitats available, and restricted exchange of water with oceanic environments (Inglis, 2001).

In each harbour, two techniques were used concurrently to identify high-risk sites where field surveys can be targeted. First, hydrodynamic models were used to simulate where discharged ballast water and the larvae of pest species are most likely to be dispersed to within the harbours. Second, detailed data and published information were collected on the preferred habitats and environmental tolerances of each of the target species. This information was used to map the distribution of suitable habitat for each species in each of the eight harbours using ‘habitat suitability indices’ (Norcross et al., 1999; Rubec et al., 1999; Brown et al., 2000). Field surveillance commenced in August 2002 using a variety of techniques, including trapping, benthic sledding, and diver and shore searches that have proven efficient for sampling the target species. The surveys were stratified within each harbour to reflect the distribution of high-risk zones identified by the initial modelling and mapping. Between 2002 and 2004, NIWA carried out a total of four series of target surveys, two during summer months and two during the winter.

Research on the invasive paddle crab Charybdis japonica

An introduced paddle crab, Charybdis japonica, has been found at considerable densities throughout Auckland’s Waitemata harbour (Gust et al., 2002) . The species first attracted scientific attention in November 2000 when two fishermen began capturing the crab from flounder nets set in the Rangitoto channel near downtown Auckland. They noticed a portunid crab with different markings and far more pugnacious attitude than the native paddle crab Ovalipes catharus they were used to. Specimens were sent to the national museum Te Papa (Wellington) where they were identified as Charybdis japonica, whose distribution was previously restricted to coastal regions of China, Korea, Taiwan and Malaysia (Kim & Ko, 1990, Jiang et al., 1998). Since these first specimens were discovered, a reproductive population of Charybdis has apparently established within the harbour in the last two years.

Since 2001, NIWA has undertaken research into the distribution and demography of Charybdis in New Zealand. Crabs were caught in two types of baited traps and were found at over 70 locations within Waitemata Harbour. Within this area, Charybdis was trapped in a wide variety of habitats throughout the harbour in depths varying from 0.5 to 12 meters, although it was more abundant in water less than 6 m deep. In 2001 and 2002, the invasive paddle crab was more widely spread and approximately twice as abundant as the native paddle crab within Waitemata Harbour. Charybdis occurred on a variety of substratum types including soft and hard bottoms (Gust et al., 2002). Since 2002, catch rates for Charybdis have dropped significantly.Ultimately the New Zealand public will want to know if this invasive crab can be managed or eradicated. While precedents do exist for the eradication of locally established marine pests (e.g. Culver & Kuris, 2000), crabs are highly mobile and very difficult to remove once widely established. C. japonica has potentially serious consequences for native biodiversity and existing ecological processes in the Auckland region.

Summary

NIWA is actively involved in the protection of New Zealand’s native marine biota through the development and implementation of effective and efficient survey and surveillance techniques for a range of introduced marine species, including both sessile and motile taxa. These techniques will help to (1) assess the current range and dis tribution of marine NIS around New Zealand, and (2) detect newly established species before they have had an opportunity to spread widely and become abundant (Crooks & Soulé, 1999, Sakai et al., 2001). Other research is aimed at the development of preventative measures that help reduce the chances for establishment of further AIS (see article on private pleasure craft in this volume). Detailed information can be obtained from the corresponding author or the NIWA website at www.niwa.co.nz.

Acknowledgments

Funding for the research described in this paper has been provided by the New Zealand Ministry of Fisheries (port surveys, target surveillance, Charybdis) and NIWA (Charybdis; NSOF project PDD035).

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nursery areas in Alaskan waters. Fisheries Oceanography 8: 50-67.Rubec, P. J., J. C. W. Bexley, H. Norris, M. S. Coyne, M. E. Monaco, S. G. Smith & J. S. Ault. 1999.

Suitability modelling to delineate habitat essential to sustainable fisheries. American Fisheries Society

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Hull Fouling as a Mechanism for Marine Invasive Species Introductions.Proceedings of a Workshop on Current Issues and Potential Management Strategies February 12-13 2004. Honolulu, Hawaii . Edited by L.S. Godwin.

Development of an Initial Framework for the Management of Hull Fouling as a Marine Invasive Species Transport Mechanism

L. SCOTT GODWIN

Hawai ´i Biological Survey, B. P. Bishop Museum, 1525 Bernice St., Honolulu, Hawai ´i 96817 USA. Email: sgodwin@bishopmuseum.org, Fax: 808-847-8252

Abstract

Hull fouling is a new management issue, and requires expert opinions from various stakeholders connected to maritime shipping, marine resource management, and marine science community. Work in Hawai ´i has focused on collaboration with an assembled group of stakeholders concerned with formulating a framework of information that will assist future management efforts for marine AIS associated with hull fouling.

IntroductionThe native species of the marine and terrestrial environments of Hawai ´i arrived as natural biological invasions through historical time, and through evolution and adaptation became the present communities associated with the archipelago. The islands of Hawai ´i are one of the most isolated areas in the world and all native plants and animals exist due to the pioneering species that settled here originally. The advent of modern history has created a new type of biological invasion by aquatic invasive species (AIS) mediated by anthropogenic mechanisms. Maritime vessel activity is the primary means of marine AIS transport to the Hawaiian archipelago and it has been determined that the biofouling associated with the hulls of these vessels is an extremely important vector (Godwin and Eldredge 2001; Eldredge and Carlton 2002; Godwin 2003). A considerable amount of management effort has focused on ballast water as a vector for marine AIS but hull fouling has received little attention. Hull fouling is a new management issue, and requires expert opinions from various stakeholders connected to maritime shipping, marine resource management, and the marine science community. This paper will focus on efforts with an assembled group of stakeholders tasked with formulating a framework of information to assist future management efforts for hull fouling. The process was conducted in conjunction with the development of the Hawai ´i Aquatic Invasive Species Management Plan in 2003.

State of Hawai ´i Aquatic Invasive Species Management Plan (HAISMP)The Division of Aquatic Resources (DAR), under the State of Hawai ´i Department of Land and Natural Resources (DLNR), initiated the development of the comprehensive Hawai `i Aquatic Invasive Species Management Plan (HAISMP). The DLNR-DAR subsequently contracted with The Nature Conservancy of Hawai ´i (TNC) to coordinate the development of the plan. Prior to this effort a Hawai ´i stakeholder group made up of representatives from the maritime industry, aquatic resource management, and the marine science community was formed inOctober 2002. This group was named the Alien Aquatic Organism Task Force (AAOTF) and it began efforts to develop administrative rules for ballast water and ballast water sediments, while also developing a preliminary information framework for hull fouling.

Collaborative process for the development of management strategiesCollaborative efforts were begun in August 2002 to form the AAOTF. The DLNR-DAR worked directly with the principle investigator (Godwin) to develop an initial list of stakeholders that were felt to represent the broadest possible expertise and representation for the maritime, scientific and aquatic resource management communities. The AAOTF was assembled in October 2002 for the first meeting, which focused on the familiarization of

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participants with one other and with the issue of marine AIS. The task force process was structured so that it was a partnership with the DLNR-DAR and TNC. Representatives from the DLNR-DAR were responsible for all activities that focused on the crafting of administrative rules for ballast water and ballast sediments, while the principle investigator was responsible for eliciting information and developing a preliminary information framework for hull fouling. These duel activities were conducted at monthly meetings and active correspondence between meetings was conducted through e-mail and phone contact. In addition, a workshop with researchers from outside of Hawai ´i was conducted in February 2003 that focused exclusively on hull fouling issues. Invitation to this workshop was extended to individuals outside of the AAOTF to achieve a greater outreach effort.

Once the workshop was conducted and AAOTF members became immersed in the issue the following months were used as an exercise in gathering and structuring information. The methodology used throughout the process with stakeholders involved standard group interview techniques facilitated by the principal investigator. An assistant recorded information that was elicited during the process on large flip charts. The first step was to establish a goal that was agreed upon by a consensus of stakeholders. This was followed by the elicitation of criteria and concerns that supported the goal, through an iterative process that spread over a period of six months. During thisprocess all the criteria and concerns were condensed into a series of generic categories and supporting sub-categories. During each meeting the material covered and recorded was posted at the front of the room on flip chart pages to allow viewing by task force participants. The information gathered at each meeting was continually condensed and categorized and presented at the beginning of each following meeting. This iterative process allowed constant updating and editing by all task force members as a group. The final process was for the facilitator to form all the information into a framework. A hierarchical framework was chosen to present the information visually but the information was further decomposed into subcategory frameworks with accompanying descriptions. As stated previously, the goal of the process was to elicit information and develop it into a framework that can be used by management professionals to develop administrative rules and management strategies.

ResultsThe overall hierarchy of information is shown in Figure 1. The hierarchy in Figure 1 represents a compilation of the criteria and concerns elicited from AAOTF members, which was then converted to generic terminology. The categories of the hierarchy will be explained in the following sections.

Generation of a goal

The creation of a goal was the first step in this collaborative process. The challenge was to create a realistic goal that could be used to guide the AAOTF throughout the entire process. This was not attempted until the end of the second day of the workshop and the group agreed upon the following goal: “Minimize marine alien species introductions by hull fouling.” It was determined by the group that the use of the word “minimize”, as opposed to “prevent,” created a more realistic goal for the process. This was based on the fact that it is impossible to prevent marine AIS associated with hull fouling with the present status of administrative rules and inspection technologies. This goal was used to guide the process of creating a framework of information that could be used to develop management strategies. The level below the goal displays the criteria that must be satisfied to achieve the goal. These are a generic representation of the concerns voiced by all AAOTF members concerning the impact of any activities that attempt to manage hull fouling as a marine AIS transport mechanism. In general, resource managers were concerned with the level of effectiveness any management strategy but at the same time the maritime industry wanted to minimize the impact to their industry and the economy of the State of Hawai i.

AIS Central Authority

Once a consensus was reach for the goal and its qualifying criteria the task of laying out a management framework was undertaken. The members of the AAOTF were told to assume an environment where monetary and personnel resources were not a limiting factor when suggesting strategies for the management framework. A consistent issue that was brought up was the need for an AIS central authority to carry out the components of any management plan. It was stated many times by the task force that such a central authority was needed to successfully handle AIS from the standpoint of maritime transport mechanisms.

Comments by AAOTF members pertaining to this issue were compiled and reviewed and a picture of a hypothetical AIS central authority took shape, which is shown in Figure 2. According to AAOTF members, if there were no resource constraints, the best approach would be the creation of a new division within the DLNR that deals only with alien species issues (terrestrial and aquatic). Existing personnel, programs and resources from within DLNR presently dealing with alien species in all terrestrial and aquatic environments would be put under the authority of this new division. The issues of AIS transport through maritime activities would be the responsibility of

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the marine AIS coordinator through federal, state and maritime industry partnerships. This scheme would also be applicable to all maritime industry transport mechanisms for AIS. This AIS central authority would use a series of pro-active, reactive and post-event measures to achieve the goal set by the AAOTF.

Figure 1. Framework for the management of marine AIS transported by hull fouling.

Figure 2. Hypothetical AIS central authority.

Pro-active Measures

These measures are geared to the task of minimizing the risk of introduction of marine AIS through hull fouling. The basis of this category is the increase of knowledge and awareness concerning marine AIS by individuals in a variety of stakeholder groups. The majority of resources available to the AIS central authority would be committed to this component.

Monitoring ProgramThe activities included in this component would be focused on monitoring maritime activities for the purpose of identifying and responding to perceived threats. Such a monitoring effort requires partnerships that can provide vessel arrival data and points of contact for follow-up investigation. These partners in Hawai ´i are: The State of Hawai ´i Department of Transportation (DOT), Harbors Division, which is responsible for managing the daily vessel activities in all commercial harbors and is responsible for keeping logs of scheduled arrivals. Similar duties focusedon marinas and personal craft are carried out by the State of Hawai ´i Department of Land and Natural Resources (DLNR), Division of Boating and Ocean Resources (DOBOR). The difference between Harbors Division and

Maximize effectiveness to

the State of Hawaii

Minimize impact to maritime

industry and state economy

Monitoring

Program

Risk Assessment

Matrix

Outreach &

Education

Pro-active

Measures

Rapid Response

Strategy

Reactive

Measures

Management

Plan

Post-event

Measures

AIS Central

Authority

Goal

Minimize marine alien species

introductions by hull fouling

Marine AIS

Coordinator

Freshwater AIS

Coordinator

Field

Technicians

Chief TechnicalOfficer (Aquatic)

Chief TechnicalOfficer (Terrestrial)

Director

New

Division

DLNR

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DOBOR is that DOBOR rarely receives prior notice for arrivals. If the log of scheduled arrivals is provided regularly to the AIS central authority by the Harbors Division, this would be a first step in managing the risk associated with hull fouling associated with commercial vessel platforms . In the case of DOBOR, notification would be after the vessel has arrived but timely notification to the marine AIS central authority would be valuable to the monitoring program.

In addition to arrivals data from both Harbors Division and DOBOR, further points of contact also could be provided. These points of contact are a necessary step in determining basic information for any vessels. Procedures for this step differ between commercial vessels and personal craft. The point of contact for all commercial arrivals is the local vessel agent, whose job is to handle all aspects of a vessels needs once cleared for arrival to the commercial harbor. All commercial vessels not associated with local operators are required to have a local vessel agent. The identity of the agent for each vessel arrival is recorded by the Harbors Division on the arrivals log. This agent can be contacted by the AIS central authority to acquire information concerning the vessel of interest. A profile of the operations of a vessel before its arrival and its intentions while in port can be determined through a brief interview. In most cases, the vessel agent will possess enough information on the particulars of the vessel that judgments can be made concerning its risk before its entry into the port.

Although not mentioned above, information can also be obtained through collaborative agreements with the partnership agencies. Agencies such as the U.S. Coast Guard and U.S. Customs conduct inspections of overseas arrivals and could collaborate by providing on-site information to the AIS central authority. This type of collaboration could provide another layer to monitoring and make the most of limited resources.

Risk Assessment MatrixThroughout the previous section the subject of risk determination is mentioned. It is not realistic to assume that every vessel entering the port system will be considered and investigated, which is reflected in the goal statement of this process (i.e., minimize vs. prevent). To narrow the focus and make the best use of resources it is necessary prioritize. Prioritization is accomplished through the practice of risk assessment, which is guided by a matrix based on simple binary choices. A draft risk matrix was formulated through the collaborative process with AAOTF members and is shown in Figure 3. This matrix is a simple representation based on factors developed by stakeholders and is not considered a final product.

The direction of flow for the matrix represented in Figure 3 is top to bottom. Each step has a binary choice that either directs the process to the next step or instructs the user to stop. If the particulars of a vessel carry the process to the end, further investigation is warranted. Each step will be described in the remainder of this section.

Figure 3. Hypothetical risk assessment matrix.

Towed Barges & Work Platforms

Floating Drydocks

Unique Arrivals

ISM Convention

Local Codes of PracticeSTOP

NO

STOP

< Time X

STOP

Acceptable

Response and Action

Unacceptable

Ranking System

Investigate

> Time X

? Lay-up or Inactivity Period

NO

STOP

YES

? Compliance to Standards

YES

? LPOC Outside

Hawaii

Priority Vessels

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High priority vessels and events

The first task is to form a list of priority vessels that are described below:

1. Towed vessel platforms: this category includes a variety of platforms towed by tug boats such as cargo and crane barges, drilling platforms and pontoon bridges. The tug boats for this and the second category would also be included as high priority vessels for the risk matrix.

2. Floating Drydocks: a category of large towed vessel platforms that can change ownership quite frequently and are subsequently moved throughout the oceans of the world. Purchasing and transporting floating dry docks to new locations is a cheaper alternative to constructing new shipyard facilities.

3. Stochastic Events: a general category that puts focus on arrivals that are not part of the regular suite of vessel arrivals to a port system. Examples would be unscheduled arrivals for medical and mechanical emergencies, salvaged vessels and decommissioned military vessels. Personal craft from overseas locations are also included in this category due to the fact that arrivals are quite unpredictable.

The justification for the first two high priority vessel descriptions is that these are slower-moving vessels with long port residence times. These factors create a situation in which the settlement and establishment of fouling organism is more likely. The third category was developed to stress the importance of random events that otherwise might be ignored by port officials and aquatic resource managers.

Step 1: Last port of call outside Hawai i

Once a high priority vessel is identified it needs to be determined whether it is arriving from outside of Hawai ´i.

Step 2: Compliance Standards

There are industry standards for the safe operation of vessels, which include maintenance of the overall vessel structure. These standards are stated in the International Management Code for the Safe Operation of Ships and for Pollution Control, referred to as the ISM Code (http://www.imo.org/home.asp?topic_id=182). The ISM Code addresses the responsibilities of those who operate and manage commercial ships (above 500 gross tonnage). This code provides an international standard for the safe management and operation of these vessels and provisions for pollution prevention. Under the ISM Code ship owners and operators are required to conduct regular safety checks and audits, which include preventative maintenance of ship structures, generically referred to as ship husbandry. The use of this as a prioritization was suggested by AAOTF maritime industry members. The justification is based on the premise that if an owner/operator of a vessel complies with the ISM Code, it is more likely that the vessel has been maintained properly, and therefore is less likely to have extensive fouling growth. The care and maintenance of the hull of a vessel is an important factor in safety and operating cost. A company that is ISM Code compliant will tend to view hull maintenance as a typical cost of operation. The U.S. Coast Guard has access to the database of ISM Code compliant vessels throughout the world and uses the lack of compliance as prioritization criterion for choosing vessels for safety inspections. Collaboration with the U.S. Coast Guard by the AIS central authority would provide access to this information for the risk matrix.

In combination to using ISM Code standards, local industry standards could be developed by the maritime community. These local standards could be disseminated to the regional maritime community to inform mariners on both commercial vessels and personal craft about this issue for Hawai ´i. Personal craft are not covered by ISM Code standards and assumptions cannot be made for hull maintenance practices. Collaboration between maritime community leaders to develop local codes of practice could only bolster international standards and provideguidance to mariners on both commercial vessels and personal craft.

Step 3: Lay-up or inactivity period

This is a step in the matrix that needs further development. The binary choice involves a temporal scale for lay-up or inactivity periods. If the set maximum value is exceeded then the matrix directs the flow to the next step. There was much debate over the maximum temporal value in the AAOTF venue and an actual value was not set. It was decided by the facilitator that a value should be based on research or standards established through experimental means. Much research has been conducted by military and private industry on fouling rates and this should be consulted to develop this step further.

Step 4: Investigate

This step involves actual investigation by the AIS central authority of a vessel determined to be a risk for marine

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AIS through hull fouling. The approach should be a gradual process that begins with a field ranking system that can be used pier-side or from a boat. This can be accomplis hed through a visual approach or by use of a remotely operated underwater camera system. The visual approach can be done through a numerical scale that ranks levels of fouling visible from the surface. This ranking system could be adopted by other agencies such as the U.S. Coast Guard or State of Hawai i Department of Agriculture, Plant and Animal Quarantine and Inspection to be used by their field personnel if they encounter a suspect vessel. DOBOR staff could also use this system to classify personal craft when communicating with the AIS central authority. This type of visual ranking system has shown promise in New Zealand when used by national inspection officers (Floerl 2004, In press), and can be used to make a quick judgment on whether to conduct more a more rigorous investigation. Another method for on-site judgments would be a remote underwater video camera system. Use of either of these methods would allow the AIS central authority to determine whether the process needs to move from pro -active measures into reactive measures that involve rapidresponse. Rapid response measures will be covered in a later section.

Outreach and EducationThis component is included here since the objective of the pro-active measures is to increase knowledge and awareness of marine AIS transported by maritime vessel activity. The monitoring and risk assessment components increase the knowledge and awareness of a specific group within the aquatic resource community and provide tools for management. An additional tool for management would be an outreach and education initiative broadly aimed at the aquatic resource community, the maritime industry and private citizens. This would allow a relatively new issue such as marine AIS transport by hull fouling to be understood by a greater number of individuals. This understanding empowers a greater pool of individuals to assist managers tasked with carrying out measures to minimize marine AIS. The AIS central authority would benefit from a raised awareness with vessel agents and Harbors Division staff since they would be passing this awareness along to vessel owners and operators that use Hawai ´i as a port of call. This would also be true with DOBOR and private marine facilities, which could inform the operators of personal craft to be more aware of hull maintenance. Outside of Hawai ´i, efforts by the AIS central authority could inform mariners and harbor authorities regionally to be more pro -active concerning hull fouling and other potential mechanisms for marine AIS transport associated with maritime vessel activity. Through the outreach program mariners will also informed of whatever existing administrative rules and penalties exist.

Reactive Measures

This aspect of the management effort would simply involve designing a scheme for reacting to events that are deemed high risk during the pro-active phase. The key to the reactive measures would be partnerships with the state and federal agencies that have both jurisdiction and management interests in minimizing marine AIS introductions.A response team (or teams) composed of personnel from these partners would be needed to investigate high risk events and recommend actions to minimize the effects of a high risk vessel.

A preliminary attempt by AAOTF members to compose scenarios and responses is shown in Table 1.Thebasic premise behind this effort by the AAOTF was to minimize the time in port for commercial and private vessels. If the vessel identified is a standard cargo vessel or a personal craft arriving from overseas, its time in port would be restricted. A standard cargo vessel would be restricted to cargo operations and then instructed to get underway. If the vessel is a personal craft it would be required to leave port once it has conducted essential activities such as fueling, maintenance and loading stores. In the case of vessels or vessel platforms intent on a long or permanent port stay, such as the examples in Table 1, different measures would be required. In these instances the vessel or vessel platform would be subject to quarantine procedures and an out-of-water hull cleaning at the vessel owner’s expense. If such measures are adopted by the State of Hawai ´i, the AIS central authority would use the outreach and education component to inform mariners locally and regionally. The possibility of incurring large costs for hull cleaning would be incentive for preventative measures before arrival to Hawai i.

Post-event Measures

The last category within the draft framework of information is the management aspect. Efforts would move in this direction once it is determined that a long term solution must be put into effect.

The main tool for managing a high risk hull fouling event is to initiate quarantine procedures. This was mentioned in the previous section without elaborating on the particulars. Quarantining would involve steps that would isolate the vessel within a discrete area in a controlled setting. Suggestions for such measures were elicited from AAOTF members.

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Table 1. Hypothetical response and action for high risk event

The only choice for isolating a large vessel is a commercial dry dock within a local shipyard facility. A dry dock would allow safe removal and disposal of fouling organisms. In the case of a personal craft, it could be immediately hauled and cleaned at a local boatyard. For this to be possible the AIS central authority, through authority of the State of Hawai ´i, could designate facilities for such operations and contract their services when the need arises.

Standard in-water cleaning of vessels is not a desired choice because this activity would serve to introduce organisms into the marine environment. This would only be a valid choice if a containment system for material removed from a vessel hull could be designed. Partnering with commercial dive companies and shipyards would be necessary to determine the feasibility of such control measures.

There is much more that needs to be done to develop an effective response to a marine AIS hull fouling event. There are few cases, except those covered in this volume, in which hull fouling has been dealt with as a management issue. Early discovery and quick response is the key to any incursion by an alien species to Hawai ´i. This is only possible through the design of strategies that clearly shown the type of response for various scenarios. This is where the multi-agency rapid response team comes into play. Overall coordination would be handled by the marine AIS central authority, which would have a set of administrative rules for guidance.

DiscussionThe efforts presented in this section are an initial step towards developing a more concrete strategy to minimize theintroduction of marine AIS to Hawai ´i through hull fouling. All information presented was elicited through a collaborative process with multiple stakeholders participating in the AAOTF. The information gathered is intended as a starting point for resource managers tasked with dealing with marine AIS for the State of Hawai ´i.

If hull fouling is viewed in the same way as any other mechanism for the transport of alien species, then the key would be the development of strategies that rely on inter-agency cooperation and partnerships with the private sector. Multi-agency cooperation is the key to present efforts concerning terrestrial alien species in Hawai ´i. The efforts conducted by state and federal agencies concerning early detection and rapid response in terrestrial environments should be used as examples in addition to the information developed in this study.

Awareness of the marine AIS issue and its connection to maritime shipping activities, both domestic and international, is an important component in the future efforts in protecting the marine environment of Hawai ´i in the face of a growing global economy. Outreach to the public sector areas tasked with the management of aquatic resources and private sector interests that conduct operations with the potential for transporting marine AIS is a required component for success. Collaborative efforts between multiple stakeholder groups will continue to be the basis for effective and useful tools to minimize the impact of marine AIS. The mindset of industry and government concerning marine AIS transport by maritime vessel activity is more complex than just regulating obvious vectors such as ballast water, and it will take awareness by both sectors to achieve the maximum positive effect for the environment and minimal impact to industry.

AcknowledgementsThis project was funded by the Hawai ´i Coral Reef Research Program 2003 Grant #Z616358. Contributions of funding, facilities and personnel were provided by The State of Hawai i Department of Land and Natural Resources-Division of Aquatic Resources, State of Hawai ´i Department of Agriculture-Plant and Animal Quarantine Branch, and The Nature Conservancy of Hawai ´i. Special thanks to Dale Hazelhurst of the Matson Navigation Co. for supplemental monetary support for workshop activities. Mahalo to all AAOTF members for their time and expertise.

High Risk Event Identified within Port

1) Standard Commercial Vessel (barge, container ship, RoRo, fishing vessel)

ACTION: Restrict time in port to cargo operations

2) Vessel platform intent on long port stay (work barges, drilling platforms,floating drydocks, decommissioned vessels)ACTION: Quarantine procedures and out of water hull cleaning

3) Personal craft (overseas arrivals)

ACTION: Restrict time in port or require out of water hull cleaning

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Literature CitedEldredge, L. G. & J. T. Carlton. 2002. Hawaiian Marine Bioinvasions: A Preliminary Assessment. Pacific Science

56: 211-212.Godwin L.S. & L.G. Eldredge. 2001. South Oahu marine invasions shipping study (SOMISS). Final report

prepared for the Hawai ´i Department of Land and Natural Resources Division of Aquatic Resources. Hawai iBiological Survey, Bishop Museum. Technical Report No. 20. 104 pages.

Godwin, L. S. 2003. Hull fouling of maritime vessels as a pathway for marine species invasions to the Hawaiian Islands. Biofouling 19 (Supplement): 123-131.

Floerl, O., G. J. Inglis & B. J. Hayden. 2004. A risk-based predictive tool to prevent accidental introductions of nonindigenous marine species. In Preparation.