Exploitation and Management of Brown Mussel (Modiolus philippinarum) Resources in Iloilo,...

Philippine Journal of Social Sciences and Humanities University of the Philippines Visayas Volume 16 No. 2, (2011) 22-34

-------------- * For correspondence email: [email protected]

Copyright © 2011 Napata, RP & Andalecio, MN

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Original Research

Exploitation and Management of Brown Mussel (Modiolus philippinarum)

Resources in Iloilo, Philippines

Ruby P. Napata* and Merlina N. Andalecio

Institute of Fisheries Policy and Development Studies

College of Fisheries and Ocean Sciences

University of the Philippines Visayas, Miagao, Iloilo

Abstract

This study examined the status of the brown mussel (Modulus phillipinarium) resources in

Dumangas, Iloilo. The coastal area of Dumangas has been known for the production of brown

mussels, but stock management has been hampered by lack of information on its exploitation.

A face to face survey interview was conducted to determine the characteristics of gatherers,

harvesting methods, production data, and perceptions on the management and conservation of

the brown mussel resources. A total of 34 gatherers, between 24 to 67 years old ( =40 + 10.3

years old), were interviewed. Involvement in this small-scale industry was not limited to male

fishers, even women and children were involved. The respondents have been harvesting

brown mussels for an average period of 9.2 + 9.5 years. Gathering was done throughout the

year, typically once a day at three hours a day and six days a week. The methods utilized were

handpicking and diving in deeper waters. The average volume of brown mussels harvested

was 43.0 + 26.2 kg per gatherer per day. This study revealed that the volume of commercial

harvest was 74% more than small-scale harvest. The estimated price of PhP3.80/kg is very

much lower than the recorded price of green mussels. Harvesting of brown mussels for food

on a subsistence basis is common in Dumangas, but they have also been used as cheap source

of aquaculture feeds. Respondents were aware of the negative consequences of resource

depletion and recommended implementation of regulatory measures including size limit,

maximum volume of harvest, and frequency of harvesting. This study found the need to enact

a municipal-wide ordinance relating to the management and conservation of brown mussel

resources. The ordinance should provide for the establishment of brown mussel conservation

zone and creation of a management body.

.

Keywords: Modiolus philippinarium, brown mussel, shellfish harvesting, Dumangas, Iloilo

In recent years, increasing global interest on

the sustainable management of marine resources

focuses on the implementation of development

policies and programs in line with precautionary

principle, adaptive management, and ecosystem-

based management. This is to veer away from the

common property problems in fisheries such as

excessive fishing fleets and effort, overexploited fish

Napata and Andalecio/ Phil. J. Soc. Sci. Hum.16, 2 (2011) 22-34

23

stocks, by-catch, unprofitability and low incomes,

low contribution to national economy, threat to the

sustainability of the fishery, and human habitation

(Arnason, 2009; Pomeroy et al., 2007; Bhat & Bhatta,

2006). According to Cole, McQuaid & Nakin (2011),

habitat destruction is not necessarily a direct

alteration of environmental conditions, but loss of

biogenic habitat and subsequent alteration of habitat

structure and abiotic conditions. To address these

concerns, management measures then become

imperative and have been widely applied. These

include area and seasonal closure, establishment of

marine protected areas and fishery reserves, habitat

restoration, and community-based governance

approaches (Wiber et al., 2010; McLaughlin, Portig &

Johnson, 2007). The effects of management are

varied across spatial and temporal scales.

Among the most important aquatic resources

in the world are molluscs. In 2008, the global

production of molluscs, which reached 13.1 million

tons, was composed of 31.8% oysters, 24.6% clams,

12.4% mussels, and 10.7% scallops (FAO, 2010).

Molluscs are mostly found in rocky and intertidal

communities, yet many of them have been subjected

to intense exploitation by coastal communities.

Previous studies have shown that intertidal molluscs

are the main target taxa for small-scale fishers (e.g.,

Jimenez et al., 2011; Colonese et al., 2011; Szabó &

Amesbury, 2011). Bivalves such as oysters, mussels,

and scallops belong to the family of molluscs.

Compared to finfishes, which are highly mobile,

bivalves are sedentary in nature and lack a well-

defined defence mechanism against predators,

especially humans, which make them more prone to

overharvesting. Of the very few bivalve species and

despite commercial significance, mussel receives very

little attention in terms of conservation and

management. Mussels make up the hard bottom

communities in coastal waters, often forming

extensive biomass accumulations on rocks, jetty piers,

and navigation buoys (Rajagopal et al., 2006). Several studies have indicated ecological services of

mussels such as ecosystem engineers or habitat

forming species (Cole, McQuaid & Nakin, 2011;

Borthagaray & Carranza, 2007; Cranfield et al.,

2003), responsible for removing large phytoplankton

biomass and wastes as well as cycling of nutrients

(Strogyloudi et al., 2006; Gao et al., 2008; Peterson &

Heck, 1999).

In the Philippines, mussels are cheap sources

of animal protein. Although many species are

reported globally, only three species of mussel are

being utilized as food in the country, namely, Perna

viridis (green mussel), Modiolus metcalfei and

Modiolus philippinarum (brown mussels). The green

mussel is the only species farmed commercially, and

its significant volume of production is sustained

entirely by the abundance of wild seeds as there are

no commercial hatchery facilities in the country.

Conversely, the two species of brown mussels are not

suitable for farming because they are not known to

attach on substrates other than living adults growing

in dense mats on muddy bottoms (FAO, 1988; Yap,

1978). From 2004 to 2013, green mussels contribute

annual landings of 19,936.50 to 22,442.71 mt (BAS,

2012), whereas no production statistics are available

for brown mussels.

Many species of brown mussel of the genus

Modiolus are mostly found in the Indo-Pacific

Region, specifically, at the intertidal and very

exposed shores where they can form extensive beds.

More information on various species of Modiolus is

available in other areas. For example, findings on the

impacts of fishing, heavy metal pollution,

biodeposition, and energy budget of Modiolus

modiolus have been discussed by Magorrian &

Service (1998), Kenchington et al., (2007), Kavun &

Podgurskaya (2009), and Navarro & Thompson

(1997). Whereas, Barile et al., (2011), Ezgeta-Balic et

al., (2011) and Lesser & Kruse (2004) have examined

artificial reproduction technology and energy budget

of Modiolus barbatus. Information on the toxicity of

heavy metals on Modiolus philippinarium have been

established by Rajagopal et al. (2006) and

Ramakritinan, Rathishri, & Kumaraguru (2012).

Brown mussels are also the preferred food of cultured

species like prawns (Penaeus monodon) and mudcrab

(Scylla serrata) (Rochanaburanon, 1980). Despite

their ecological importance, the literature on

Modiolus in the Philippines is scarce. The limited

information available on their distribution, biology,

and settlement are found in Tumanda et al. (1997) and

Yap (1978). Also, the extent of exploitation and

effects of harvesting are poorly documented, but

ongoing anthropogenic activities in the coastal areas

may indicate steady exploitation that threatens

resource recovery. Thus, in order to recommend

appropriate management measures, this study

examined the status of the brown mussel resources in

one of the coastal areas in the province of Iloilo.

In Iloilo, two areas are known for the

production of brown mussels, and these are Banate

Bay and Dumangas. However, no studies were

conducted on the exploitation and management of the

brown mussel in both areas. An assessment of the

effects of exploitation has been hindered by lack of

data on natural fluctuations of stocks. The only

available information from Banate bay was the brown

mussel’s settlement preference. The municipality of

Anilao which is situated in the bay regulated the

collection in an attempt to prevent overharvesting that

may ultimately lead to species disappearance. In

Dumangas, baseline information is also very

inadequate. Based from historical accounts, the

gathering of brown mussels in Dumangas has been

practiced as early as the 1970s. With increasing


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aquaculture demand, brown mussels were used as

feeds for cultured mudcrabs.

Methodology

Study Site

This study was conducted in the

municipality of Dumangas, which lies 122°42’34”

longitude and 10°49’22” latitude, and has a total

coastline of about 21.6 km (Figure 1). Aside from

several creeks and springs, seven major rivers which

traverse the municipality provide the residents of the

locality with important fisheries resources. The

coastal area has extensive seagrass beds estimated to

be about 450 to 750 ha along 1.5-2 km shoreline at a

depth of 3-5 m, and diverse species of mangroves

(CRM Plan, 2009). Several man-made structures were

established on the coast namely, fishpens, cages,

oyster and mussel farms, and fish traps. Various

species of finfish and shellfish are caught in the

coastal waters including, slipmouths, croakers,

siganids, mackerels, groupers, nemepterids, crabs,

and shrimps. Of the shellfish fishery, mollusc is an

important group which has been exploited in great

volume from the intertidal areas, riverbanks,

mangroves and seagrass beds. The southern side of

the coastal area has been regarded as rich in mussel

resources.

Data Collection and Analysis

A face to face survey interview was

conducted using a pre-tested questionnaire which was

translated to the local language Ilonggo. The survey

questionnaire included socio-demographic profile,

harvesting methods, production data, and perceptions

on the management and conservation of the brown

mussel resources. The interviews were conducted

from August to November 2007 in six coastal

barangays namely, Bacay, Bolilao, Dacutan,

Lacturan, Paloc Sool and Sapao. Focus group

discussions with barangay captains, Barangay

Fisheries and Aquatic Resource Management

Councils (BFARMCs) chairpersons, and Agriculture

Technician for fisheries were also conducted to solicit

additional information and validate the information

collected from the interviews. The location of brown

mussel beds was identified from the interviews, and

the area covered was estimated using the Garmin 76

Mariner Global Positioning System (GPS). The

species of brown mussels were identified through the

assistance of Dr. Liberato Laureta of the Institute of

Aquaculture, College of Fisheries and Ocean

Sciences, University of the Philippines Visayas. The

primary data were supplemented with secondary

information such as municipal fisheries profile and

ordinances, memoranda of agreement, and technical

reports. Descriptive statistics was used to describe the

demographic characteristics of the respondents and

production data.

Figure 1. Location of Dumangas, Iloilo.


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Results

Profile of Brown Mussel Gatherers

The brown mussel beds in the municipality

of Dumangas were found in the 13.3-km stretch of

coastline covering an estimated area of 26.4 ha

(Figure 2). Mussel harvesting supports the livelihood

of about 150 gatherers from six barangays namely

Bacay, Lacturan, Dacutan, Sapao, Paloc Sool, and

Bolilao. A total of 34 respondents were interviewed,

representing 23% of the total brown mussel gatherers.

Their socio-demographic profile is shown in Table 1.

Most respondents were married males (70%), and

whose main sources of income were brown mussel

harvesting and fishing (Figure 3). The age of the

respondents ranged from 24 to 67 years old ( =40 +

10.3 years old). They have been involved in brown

mussel gathering from less than one year to 31 years

(( =9.2 + 9.5 years). For the respondents, engaging

in brown mussel harvesting has been an important

means to augment their family’s daily needs and

provide for their children’s education, especially for

those who have been in the business for 31 years. The

respondents who have been harvesting brown mussels

for over ten years were mostly from barangays Bacay

and Lacturan. Some who were new in the business

became gatherers only when the comprador or traders

entered the municipality and purchased huge

quantities of brown mussels.

Brown Mussel Species and Harvesting Methods

The species of brown mussel in the coastal

waters of Dumangas was identified as Modiolus

philippinarum. This species is known to attain sexual

maturity in three months, and spawns all year round.

Figure 4 shows M. philippinarum measuring between

1.0 to 1.25 inches that were sold to a comprador from

Capiz. These brown mussels were used as feeds for

high valued culture species like mudcrabs. The results

of the interviews revealed that brown mussels were

mostly harvested in barangays Paloc Sool, Bacay,

Sapao, and Dacutan. Family members were involved

in gathering, including women and children, either

individually or in groups. Each gatherer would

usually cover an average area of about 5 + 6.3 ha.

One respondent who was also a trader disclosed that

he contracted ten unlicensed gatherers to sell all their

harvests to him. Harvesting was done throughout the

year, with most respondents (74%) doing it once a

day (especially during low tide) at an average of three

hours a day and six days a week. The methods

utilized were handpicking or collection using bare

hands (74%) in the intertidal or shallow areas, and

diving (26%) in deeper waters. Small-scale gatherers

would select only big mussels (>2.5 inches) and in

small amount (e.g., one pail equivalent to 3-6 kg).

With diving method, brown mussels were harvested

in commercial quantity. Harvesting was done by

removing lumps of mussel from the substrate and

transferring them inside a rectangular collection box,

locally known as ‘ayagan.’ Ayagan, which measures

1.2m x 1.8 m, is made up of bamboo slats and plastic

containers as floaters (Figure 5). When the ayagan is

filled, the lumps of mussel are shaken thoroughly to

remove the mud and byssal threads. This process then

separates the mussels individually. The bamboo slats

were designed to allow the removal of debris, byssal

thread mass, and very small mussels. However, the

young mussels dislodged from the mats could have

been severely stressed with the removal of their

byssal threads, and are unlikely to survive when they

settle back to the substrate. This method of harvesting

may be considered non-selective and inefficient.

Also, when ‘ayagan’ is used, no sorting or size

selection is done compared to handpicking. Male

respondents mostly employed the diving method,

whereas women and children were into handpicking.

Brown mussel gatherers claimed that the growing

areas have become sparse or “patchy”, which may

indicate an overexploited condition contrary to what a

healthy mussel bed should look like i.e., forming a

dense mat.

Production Data

In this study, the total volume of production

was estimated with a degree of caution. Because the

distribution of mussel beds has become patchy, the

estimated daily and annual production data were

computed based on the quantity collected by

individual gatherers per unit time and not on the total

area gleaned. The volume of brown mussels harvested

was between 4.5 kg to 125.0 kg per gatherer per day,

averaging about 43.0 + 26.2 kg per gatherer per day.

The mean harvest by diving was 61.6 + 34.7 kg per

gatherer per day, whereas that of handpicking was

35.43 + 17.8 kg per gatherer per day. So with 150

gatherers and 6 days a week harvesting, the total

volume of mussels collected from the waters of the

Dumangas was estimated to be about 6.5 + 3.9 tons

daily, or 2,019 + 1,230 tons per year. Brown mussels

were sold fresh or processed. When sold fresh, they

can either be shell-on or without shell locally termed

as ‘tinala.’ Children ages 7 to 10 were also involved

in the activity called ‘tala’ (Figure 6). The average

selling price of shell-on was PhP190.8+107.8 per

sack (price range: PhP30-400 per sack) or PhP50 per

tray or pail. A sack and pail of brown mussels

weighed about 50 kg and 6 kg, respectively. Thus, the

estimated price of brown mussel was PhP3.80 + 2.20

per kg. The processed mussels called ‘ginamos’ were

sold at PhP25.00 per bottle. The female members of

the family mainly market brown mussels within

Dumangas, neighboring municipalities, and Roxas

City in the province of Capiz (Figure 7).


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Figure 2. Harvest areas of brown mussels in Dumangas.

Table 1. Demographic characteristics of the brown mussel gatherers in Dumangas. Characteristics Category All samples (N=34)

Gender Male 24

Female 10

Age (years) Mean 40

Maximum 24

Minimum 67

Marital status Married 33

Single 1

Location of residence of brown mussel gatherers

Bacay 9

Bolilao 1

Dacutan 9

Lacturan 10

Paloc-sool 2

Sapao 3


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Figure 3. Major and minor sources of income of brown mussel gatherers.

Figure 4. Brown mussel species collected from barangay Bacay.


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Figure 5. A rectangular collection box, locally known as ‘ayagan’, used in commercial harvesting of brown

mussels.

Figure 6. Children involved in harvesting activity called ‘tala’.


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Figure 7. Areas where brown mussels from Dumangas were marketed (multiple responses).

Management and Regulatory Aspects of Brown

Mussel Resources

More than half of the respondents (56%) had

paid the annual municipal permit (PhP150 to PhP260)

and barangay clearance (PhP20) allowing them to

harvest shellfish. In addition, they also paid the

required PhP5 for every sack of brown mussels

transported outside the municipality. However, those

who refused to pay the permits reasoned that brown

mussel is an open resource and anyone from

Dumangas should be allowed to collect it at no cost.

Most respondents (91%) indicated that they were not

receiving assistance from the government for the

brown mussel industry. Over 80% of the respondents

were knowledgeable of existing fishers organizations

such as Barangay Fisheries and Aquatic Resource

Management Councils (BFARMCs) and Dumangas

Federation of Fisherfolks, Inc. (DUFFI), but only

47% were members of these organizations. More than

half (62%) of the respondents were familiar with

regulations on the harvesting of brown mussels,

which include size limit (i.e., more than 1.5 inches

should be harvested), frequency of harvesting which

is three times a week, restricted to the residents of

Dumangas, and issuance of the required permit to

gather. Some respondents mentioned that they have

known about the harvest size restriction only from

other gatherers. The gatherers were also prohibited

from completely harvesting all stocks. According to

them, the officials and members of BFARMCs collect

the barangay tax, and would normally monitor the

area to deter encroachment by outsiders.

All respondents agreed that there is a need to

manage and conserve the brown mussel resources,

and they recommended that management should

focus on the following:

Setting size limits

Specific ordinance on brown mussel

harvesting

Delineation of the municipal waters of

Dumangas

Leaving at least 10% of spawner or adult

brown mussel

Presence of active law enforcement team

Strictly implementation of the regulation that

brown mussel is exclusively for the residents

of Dumangas

Limit on the volume of harvest (e.g., 1 sack

per person per day)

In Dumangas, there was no specific policy

exclusive to brown mussel resources, but the

information in Table 2, although insufficient, may

address some regulatory concerns. Because of

extensive collection and increasing volume of

harvest, the barangay officials of Bacay were


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prompted to formulate Ordinance No. 02-2006. The

ordinance imposes collectible tax and requires all

brown mussel gatherers and traders/buyers operating

in the coastal vicinity of the barangay to secure a

barangay clearance and Mayor’s permit. In addition,

the ordinance sets the following provisions:

Brown mussels found in the coastal vicinity

of barangay Bacay is for all Dumangasanon

only;

The barangay imposes PhP5.00 tax for every

sack of brown mussel, and a maximum of

two (2) sacks per gatherer;

The harvested brown mussel will be subject

for inspection by an authorized person from

the Barangay Council;

The allowable size for harvest should be two

(2) inches and above.

Table 2. Some policies of the municipality of Dumangas related on management and conservation of brown mussel

Classification Ordinance Provision

Permitting/Licensing Ordinance No.2004-01, Chapter IV, Section 19

Gives priority to resident municipal fisherfolk

Ordinance No.2004-01, Chapter IV, Section 17

There should be a registry of municipal fisherfolk and fish worker

Ordinance No.2004-01, Chapter VI, Section 34

No person, partnership, association, corporation, cooperative shall gather or culture oyster and mussel within the municipal waters without permit or license issued by the Mayor in accordance with the provision of this Ordinance

Ordinance No. 2005-22, Section 39E

Shell gathering with Mayor’s permit of PhP150.00.

Ordinance No. 2005-22, Section 39N

Registration fee for fisherfolk/fishworker of P5.00

Prohibitions on Illegal Activities

Ordinance No.2004-01 Chapter 5, Section 22.6

Protection of the marine environment and imposition of appropriate penalties for acts which endanger the environment, such as dynamite fishing and other activities, which result in population or ecological imbalance

Ordinance No.2004-01, Chapter X, Section 75

It is unlawful for any person or entity to collect, gather or sell scallop locally known as “tikab” less than five (5) inches measures from the hinge of the shell, and other mollusks or shelled-fishes which does not reached the maturity stage, or as may be determined by the national government and or accredited institutions

Protection/Conservation Measures

Ordinance No.2004-01, Chapter X, Section 45b

The vicinity of the Lapuz-lapuz islet in Brgy. Bacay and Paloc Sool containing an area of 89.134 hectares is designated as fish and marine sanctuary. The area is designated for the exclusive use of the government for the propagation, education, research and scientific purposes. It is hereby prohibited for any person to fish, extract/collect shells, seaweeds or conduct any form of activity such as boating, mooring, and various fishing techniques or other activities harmful to the ecosystem in the area.

Ordinance No.2004-01, Chapter X, Section 61

It shall be unlawful for any person, association or corporation to gather, collect, or kill marine life inside the marker where the marine sanctuary is established. That within the core of the fish sanctuary and breeding area, fishing or collection of marine life is not permitted.


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There were cases when the implementation

of the said Ordinance was challenged. One of these

transpired on September 2007 when the local

Philippine National Police (PNP) confiscated a truck

load of brown mussels in Bacay. In view of this, a

joint Memorandum of Agreement (MOA) was

formulated between the local government through the

Mayor, gatherers, traders and the barangay captain.

Based on interviews, the agreement contained the

following provisions: a) Gatherers may only harvest

brown mussel of mature and marketable size, ranging

from 1.5-2 inches; b) Harvesting may be be done on

Mondays, Wednesdays, Fridays, Saturdays, and

Sundays; c) Harvest is limited to no more than two

(2) sacks per person per day. In Lacturan, a MOA

was also signed between the barangay captain,

president of Brown Mussel “tahong” Hunters

Association and the local government. The agreement

included: a) Gatherers may only harvest brown

mussel of mature and marketable size, ranging from

1.5-2 inches; b) Harvesting may be done throughout

the week (Mondays to Sundays); c) Harvest is limited

to no more than one (1) sack per person per day.

Because Lacturan residents would also gather brown

mussels in front of Bacay, the municipality has

designated harvest areas for these two barangays so as

to avoid conflicts among gatherers. The barangays

were then expected to be responsible in managing the

brown mussel resources in their respective areas.

Discussion and Conclusion

The fishing communities of Dumangas have

been engaged in brown mussel harvesting for several

years now. Although the industry does not contribute

much to the local economy compared to other

fisheries and aquaculture industries (e.g., milkfish and

prawn culture), it is a secondary source of income for

fishers and their families. Involvement in this small-

scale industry was not limited to male fishers, even

women and children were involved. This situation is

similar to the studies of Frangoudes, Marugán-Pintos,

& Pascual-Fernández (2008), Aswani & Weiant

(2003), and Kyle, Robertson, & Birnie (1997), which

indicate that women and children are also actively

involved in shellfish harvesting. Harvesting of brown

mussels for food on a subsistence basis is common in

Dumangas, but they have also been used as cheap

sources of aquacultures feeds. The study of

Rochanaburanon (1980) has demonstrated that

marketable size and small brown mussels (Modulus

metcalfei) have higher protein content (71.49% and

67.10% dry weight, respectively) than the marketable

size green mussel (Perna viridis), 63.94%. This may

be comparable to the protein content of trash fish and

the highly expensive formulated feeds for finfish.

Although two species of brown mussels

were found in the Philippines, only Modulus

philippinarium was identified in Dumangas. Jimenez

et al. (2011) described harvesting of intertidal fauna

as an informal and opportunistic activity that is

difficult. Among the potential impacts they identified

include decreases of catch densities, trampling related

degradation of habitats, and changes in community

composition. In general, harvesting mussels from

their natural habitat involves cutting of byssus threads

(Rajagopal et al., 2005). Compared to other species of

mussels which when manually detached would

quickly produce byssus threads and re-attach to any

solid surface (Rajagopal et al., 2005), Modiolus once

removed from a living surface will unlikely to re-

attach themselves, and will eventually die. This

would mean that precautionary measures should be

considered during harvesting. Indiscriminate

harvesting may compromise the integrity and

recovery of seabed which according to Trigg &

Moore (2009) may be an important function of byssal

threads of bivalves. In this present study, the two

harvesting methods (i.e., hand picking and diving

using ‘ayagan’) have some disadvantages. Although

handpicking is small-scaled and more selective

because gatherers may only collect the prescribed size

of 1.5 to 2.0 inches, there is still a possibility that

when gatherers are not cautious in harvesting, this

would create disturbance that will have the potential

to cause physical changes to the mussel beds. This is

especially the case when children are involved. On

the other hand, the diving method is non-selective,

and therefore, even smaller mussels are being

collected.

It is believed that spawning of brown

mussels is throughout the year because spat can be

found in significant quantities in the environment.

Such availability could have resulted to more

commercial harvesting, as revealed in this study that

the volume of commercial harvest was 74% more

than small-scale harvest. Should the demand for

brown mussels from aquaculture continue to increase,

commercial harvesting will most likely intensify. The

presumed abundance in the wild could have also

lowered the market price of brown mussels. In fact,

the estimated price of PhP 3.80/kg is very much lower

than the PhP 14.5/kg price of green mussels in Iloilo

in 2010 (BAS, 2012). However, without baseline data

on price trend, this assumption requires further

validation.

The notion that a natural resource is infinite

and its use is not supposed to incur a corresponding

fee is still prevalent among coastal fishers. But

respondents who were aware of the negative

consequences of resource depletion opted for the

implementation of regulatory measures. Respondents

who recognized the need to set harvest size restriction

mentioned that too many gatherers have been

harvesting smaller sizes of brown mussels. Also,

there was no restriction on the number of brown

mussel gatherers. Harvest control regulations were


32

only implemented in barangays Bacay and Lacturan

through Memoranda of Agreements. The salient

features of the agreements are size limit, maximum

volume of harvest, and frequency of harvesting.

There was no mention as to the basis for these

regulations. However, the size limit of 1.5-2.0 inches

is similar to the minimum length of 50 mm (or 2

inches) permitted for harvesting Modiolus barbatus in

the Mediterranean coast, which is attained on the

third year of life (Barile et al., 2011). The two

agreements have limitations because these are not

legally binding. But these can serve as bases for the

enactment of a municipal-wide ordinance relating to

the management and conservation of brown mussels,

as suggested by the respondents. The ordinance

should provide for the establishment of brown mussel

conservation zone and creation of a management

body. The management body shall be responsible in

the issuance of permits, prioritization of gatherers,

and law enforcement in the conservation zone.

Management strategies to be identified should be

based on stock assessment studies and detailed

surveys. These shall include among others, size limit,

frequency of harvest, permissible volume of harvest,

maximum number of gatherers at any given time, and

issuance of limited number of permits or licenses. If

the harvesting is whole year round, it may be

appropriate to designate closed season. Albeit the

municipality has not yet delineated its municipal

waters, this should not be an impediment in the

formulation of this ordinance. The recommendation

of the respondents to retain 10% spawners or mature

brown mussels may be conservative, and its

implication should be further examined. The findings

of this study provided a starting point from which

further management of brown mussel resources could

be done.

Acknowledgment

This study was conducted as part of the

CIDA-funded project “Principles in Practice (PIP):

Ocean and Coastal Governance in Vietnam and the

Philippines”. We would like to express our gratitude

to the following for their assistance in the conduct of

the study: Alan Dino Moscoso, Micah Espia and

Alvin Bandorio for their help during data collection;

Dr. Liberato Laureta, for his assistance in species

identification; local government officials especially

Marlene Amora; brown mussel gatherers from

barangays Bacay, Bolilao, Dacutan, Lacturan, Paloc

Sool and Sapao as my respondents; and Recardo

Mieux for his comments on the manuscript.

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