SEAFDEC AQD 1996-1997 Report...commercial farms. Nine studies on commercial production of milkfish...

SEAFDEC AQUACULTURE DEPARMTMENT

1996-1997 REPORT

FOOD SECURITY

THROUGH AQUACULTURE:

TOUCHING MORE LIVES

IN THE NEXT MILLENNIUM

SEAFDEC-AQD

The Southeast Asian Fisheries Development Center (SEAFDEC) is a regional treaty organization established in 1967 that aims to promote fisheries development in the region. Its member countries are Japan,

Brunei Darussalam, Malaysia, the Philippines, Singapore, Thailand, and Vietnam.

SEAFDEC is headed by a Secretary-General. The SEAFDEC Secretariat is based in Bangkok, Thailand. A Council of Directors composed of representatives from the member countries serves as SEAFDEC's policymaking body.

The Aquaculture Department (AQD), based in Tigbauan, Iloilo, Philippines, is one of four departments established that constitute SEAFDEC. The other departments are the Training Department in Samut Prakan, Thailand, the Marine Fisheries Research Department in Changi, Singapore, and the Marine Fishery Resources Development and Management Department in Kuala Terengganu, Malaysia.

AQD is mandated to promote and undertake aquaculture research relevant and appropriate to the region, develop human resources for the region, and disseminate and exchange information on aquaculture.

AA QQ DD HHEEAADDQQUUAARRTTEERRSS:: Tigbauan, Iloilo 5021 Philippines Telephone: (63-33) 335-1009, 336-2891, (0912) 304-8302 Cable: SEAFDEC. Iloilo Email: [email protected]

MANILA OFFICE: Metro Manila, Philippines Telephone: (63-2) 372-3980 to 3982 Cable: SEAFDEC, Manila Telex: 29750 SEAFDEC PH Fax: (63-2) 372-3983

Food Security Through Aquaculture: Touching More Lives in the Next Millennium. 1996-1997 Report, 1998. Aquaculture Department, SEAFDEC, Tigbauan, Iloilo, Philippines. 64 pp. ISSN: 97-8511-34-2

Produced by the Training and Information Division, AQD

Writers: Eva T. Aldon Romeo Y. Buendia Milagros T. Castaños Nelly Joy P. Dagoon Augusto P. Surtida Marilyn B. Surtida

Photography: Romeo Y. Buendia Isidro T. Tendencia

Publication Design: Augusto P. Surtida

Development Communication Consultant:

Antonio S. Frio

FOOD SECURITY THROUGH AQUACULTURE: TOUCHING MORE LIVES IN THE NEXT

MILLENNIUM

1996-1997 REPORT AQUACULTURE DEPARTMENT

SEAFDEC

Contents FForeword i

Executive Summary 1

Introduction 2

Research Output 3

Number of studies conducted 3

Research work published and presented in scientific meetings 5

Best paper awards 5

Collaborative research 6

Thesis research 8

Service Laboratories 8

Research Findings 9

Marine and Brackishwater Fishes 9

Freshwater Fishes 19

Crustaceans 23

Molluscs 27

Seaweed 29

Environment, Ecology and Other Studies 30

Socio-economics Research 38

Technology Verification 42

Training Activities 45

Information Dissemination 49

Administration 56

Looking Ahead 59

Annex 60

FOREWORD

This 1996 and 1997 biennial report highlights the research and development activities of the Aquaculture Department (AQD) of the Southeast Asian Fisheries Development Center (SEAFDEC).

During this time, AQD's new management embarked on reinvigorating its task in reaching out to more users and beneficiaries of the Department's generated aquaculture technologies in the Southeast Asian region.

The Department's thrust focused on aquaculture technology verification and technology transfer, an important component of the research-extension continuum. With this new emphasis, AQD actively pursued its research, training and information activities on identified targets and priorities.

Following this direction, nine technology verification projects were conducted in selected aquaculture farms and other sites. In addition, the milkfish hatchery technology developed by AQD is now being applied in private hatcheries. This is being implemented through the accelerated milkfish hatchery technology project spearheaded by AQD in collaboration with the private sector. This early, AQD's technology verification projects are achieving very encouraging results. One study showed that grouper culture in brackishwater ponds is a commercially viable alternative to shrimp production.

The AQD's research and development activities address four critical areas of national and regional concern: poverty alleviation, food security, environment-friendly technology, and export and cash crops

Along these lines, AQD has started to address the poverty alleviation agenda of small fisherfolk. AQD's community fishery resource management (CFRM) project mainly focuses on these technology users. Now in its sixth year, the project utilizes participatory techniques and community-based management principles in developing technologies suitable to small fisherfolk. Results of some studies in this project have proved promising. Potential collaborative projects with other SEAFDEC member countries are now being studied.

Other AQD research efforts aim to contribute to the poverty alleviation concern. These include development of technologies for mud crab culture in mangroves, and tilapia culture in cages in small water impounding systems.

Food security is another concern that AQD vigorously responds to. AQD's studies on efficient and cost-effective tilapia culture and production are designed to address the food security concern.

AQD also addresses environmental problems brought about by intensive shrimp culture. Current research is aimed at developing both short- and long-term solutions. As a short-term remedy, AQD is encouraging shrimp growers to shift to or rotate their crops with other commodities like grouper, milkfish and mud crab. Meanwhile, several environment-friendly studies are being undertaken to minimize or eliminate the problem. These are in the areas of efficient feed

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FOREWORD AQD 1996-1997 REPORT

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formulation, better culture techniques, and effective waste management. One major ongoing environmental study is the Laguna de Bay research project. This is intended to develop a predictive model for an ecosystem approach to sustainable management of the lake.

Several projects are also being conducted on aquaculture export and cash crops. These are studies on improved technologies for production of mud crab, giant tiger shrimp, grouper, sea bass, and red snapper.

In view of all these developments, AQD views the coming years with much enthusiasm. Looking ahead, AQD shall consciously strive to achieve more breakthroughs for the region's aquaculture industry. Aquaculture in the near future shall become more intensive and demand for technology will expand much more. AQD's response will revolve around the development, application and use of advanced scientific methods in generating more relevant technologies. This way. AQD shall be able to perform its technology development mandate with due consideration of economic viability, social equitability and environmental sustainability. •

ii

EXECUTIVE SUMMARY

In 1996 and 1997, the Aquaculture Department (AQD) of the Southeast Asian Fisheries Development Center (SEAFDEC) conducted 27 research projects consisting of 112 individual studies. Complementing these activities were projects

conducted in collaboration with several international and national institutions and private organizations.

During the reporting period, AQD researchers produced 71 papers which were published in international journals and in proceedings of scientific meetings.

AQD's generated technologies are being tested in technology verification studies in commercial farms. Nine studies on commercial production of milkfish hatchery-reared fry, mud crab, grouper, shrimp, tilapia, oyster and mussel were conducted in cooperation with 24 private farms and government institutions in the Philippines. At this time, the grouper, mud crab and milkfish verification projects show promising commercial viability.

In previous years, AQD has achieved much progress in developing better diets for aquaculture. Thus, several studies are focusing on feed development. Other research activities generated new information related to crop protection. Bacteria, viruses, and snail pests are a prime concern in fish health and farm management studies.

Improved hatchery techniques continue to be developed and tested. Work on freshwater fishes highlights some promising results in more efficient ways of broodstock management.

Inroads to better understanding of the behavior of Laguna de Bay lake in the Philippines have been established. A simulation model to predict water quality of the lake has been developed.

AQD is also into research on fishery resource management methods for coastal communities. A development-oriented research project implemented by AQD in a fishing community in Malalison Island, Philippines, has come up with very encouraging results. The project has proven that communities can develop and benefit from their action programs through technical assistance from research institutions like AQD and the local government institutions. The project's experience will be shared with other countries in the region.

The training and information dissemination activities of the Department also continue to be implemented. For the first time, AQD conducted a training course outside the Philippines. This was the two-week training on coastal aquaculture and resource management held in Vietnam. In addition, fourteen regular and special training courses on various aspects of aquaculture were conducted. Some 320 participants from SEAFDEC member countries and other countries attended these courses.

AQD is now in cyberspace. It has a web page in the Internet, which features AQD's current research and development activities. Since its inception in 1997, the web page has registered more than 500 website visitors.

The Department also continued to produce more publications and other extension materials. It has come up with 9 new publications and a motivational videotape on mangrove conservation. It also reprinted 9 extension manuals and pamphlets. Several articles about AQD activities were likewise written and published in the local mass media. •

1

INTRODUCTION

AQD started its 1996 and 1997 research and development activities

with a more focused effort in its technology verification studies. It actively continued its commodity research on the major marine and brackishwater fishes, freshwater fishes, crustaceans, molluscs and seaweed along several priority problem areas. In addition, the Department conducted several studies that dealt with community fishery resources management, environment, and other important research areas.

RESEARCH OUTPUT

Number of Studies Conducted

In 1996 and 1997, AQD implemented 27 research projects consisting of 112 studies (Table 1). Of these, 45 were new-studies, which were started in 1996 and 1997. Continuing studies numbered 77. These were the studies that were started before 1996 and were continued during the reporting period.

Fifty studies were completed and the rest are ongoing (Table 2). Of the completed studies. 15 were new studies and 35 were continuing research.

AQD's research program continued to focus heavily on three economically important commodities: tiger shrimp, milkfish and grouper (Table 3). Ther

TTable 1. Projects and s tudies conduc t ed by A Q D in 1996 and 1997.

Project Title Number of Studies

Marine and brack ishwater f ishes 1. Milkfish broodstock management 2. Milkfish seed production 3. Milkfish culture 4. Broodstock management and seed production of grouper 5. Nursery and grow-out culture of grouper 6. Broodstock development and seed production of mangrove red snapper 7. Nursery and grow-out culture of red snapper 8. Nursery and grow-out culture of sea bass 9. Breeding and seed production of ornamental fishes

10. Seed production and growth enhancement in the rabbitfish

Freshwater F ishes 11. Selective breeding and broodstock management of tilapias 12. Breeding and seed production of the Asian catfish 13. Broodstock management and genetic improvement of bighead carp

Crus taceans 14. Shrimp broodstock development 15. Refinement of shrimp culture system 16. Shrimp health management 17. Mud crab broodstock and seed production 18. Mud crab culture

Mol luscs 19. Broodstock management, seed production and grow-out culture of the

tropical abalone

Seaweed 20. Monoculture and polyculture of Gracilaria and Gracilariopsis

Gene t i cs 2 1. Genetic characterization of hatchery-bred, farmed finfishes, shellfish

and endangered finfishes and shellfishes

Soc io - e conomics 22. Impact analysis of the community fishery resource management (CFRM)

project on Malalison Island 23. Socio-economic indicators in evaluating the CFRM project on Malalison Island

Environment , e co logy and o ther s tudies 24. Laguna de Bay, Philippines: an ecosystem approach to sustainable management 25. Larval food project 26. Mangrove aquasilviculture 27. Viral and bacterial etiology of the epizootic ulcerative syndrome (EUS) In fish

2 8 9 6 3 4 1 8 1 1

4 4 1

4 9 7 4 4

7

4

2

3 4

6 3 2 1

Tota l 112

3

RESEARCH OUTPUT AQD 1996-1997 REPORT

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* 3 studies were deferred. 3 were merged with other studies. New studies are those started in 1996 or 1997: continuing studies are those started before 1996 and are currently ongoing.

*Socio-economics, environment and ecology, genetics, etc.

TTable 2 . Comple t ion s ta tus o f n e w and con t inu ing A Q D studies , 1996-1997.

Status*

Completed Ongoing

Continuing Number

35 42

Total 112

Percent

31.2 68.8

100.0

New Number

15 30

45

Percent

33.3 66.7

100.0

Number

50 72

115

Total Percent

44.6 55.4

100.0

Table 3. Commodi t i e s covered in research s tudies conduc t ed in 1996 and 1997.

Commodity

Tiger shrimp Milkfish Grouper Mud crab Sea bass Molluscs Red snapper Tilapia Seaweed Catfish Rabbitfish Bighead carp Marine ornamental fish Others*

Total

Number of Studies

Number

20 19 9 8 8 7 5 4 4 4 1 1 1

21

112

Percent

17.9 16.9 8.0 7.2 7.2 6.2 4.4 3.6 3.6 3.6 0.9 0.9 0.9 18.7

100.0

Table 4. Problem areas inves t i g a t ed in AQD research, 1996-1997.

Problem Area

Hatchery and nursery techniques Farming systems and ecology Breeding, broodstock development

and management Feed development and nutrient

requirements Fish health Socio-economics

Total

Number of Studies

29 25

22

21 8 7

112

Percent

25.8 22.3

19.6

18.8 7.1 6.4

100.0

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were also 21 research studies on socio-economics, environment and ecology, and genetics.

Six problem areas in aquaculture research continued to be investigated (Table 4). A fourth of the research activities was devoted to hatchery and nursery techniques. On the other hand, research efforts were about equally distributed in areas on farming systems, breeding, broodstock development and management, and feed development and nutrient requirements. The studies on fish health lay emphasis on the current disease problems of the prawn industry.

Research Work Published and Presented in Scientific Meetings

AQD continued to publish its research in scientific journals and proceedings of scientific meetings (Tables 5. 6. Annex). A total of 71 papers was published in both international and local publications. Research papers on tiger shrimp contri-buted the highest number of 17 articles. This was followed by papers on milkfish and seaweed with 9 publications each.

Several research papers were likewise presented by AQD researchers in local and international scientific conferences. Sixteen papers on studies on tiger shrimps were presented. On the other hand. 18 papers, mostly on socio-economics research, were also discussed in these meetings.

Best Paper Awards

In 1996 and 1997. AQD researchers again received recognition from the scientific community for papers they presented in scientific meetings. During these two years, AQD research papers consistently earned the Elvira Tan Memorial Award sponsored by the Philippine Council for Aquatic and Marine Research and Development (PCAMRD). This award honors outstanding research in various fields of fisheries development.

The following authors and their papers were cited:

1) T.R. de Castro and N. G. Guanzon Jr., "Growth of Gracilaria sp. (Gracilariales. Rhodophyta ) in brackish water ponds at different stocking densities"

2) E. C. Amar. R. M.T. Cheong and Ma. V. T. Cheong, "Small-scale fisheries of coral reefs and the need for community-based resource management in Malalison Island. Philippines"

3) A.E. Santiago and R.P. Arcilla. 'Tilapia culture and the dissolved oxygen trends in Sampaloc Lake, Philippines"

4) C.B. Santiago and O.S. Reyes, "Effects of dietary lipid source on reproductive performance and tissue lipids of Nile tilapia. Oreochromis niloticus (Linneaus) broodstock"

A.E. SANTIAGO C.B. SANTIAGO

DE CASTRO GUANZON AMAR

5


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* Includes research on community-based fishery management, diseases, environment and ecology, etc.

* Includes research on community-based fishery management, diseases, environment and ecology, etc.

Collaborative Research

AQD conducted collaborative research work with several international, regional and national organizations, and the private sector from foreign countries (Table 7).

Twenty (20) studies are being conducted in cooperation with 8

international institutions. 5 national institutions and with 3 private sector organizations from Switzerland. Denmark and the Philippines. Two research projects are planned to be implemented in collaboration with two SEAFDEC Departments: Malaysia's Marine Fishery Resources Development and Management Department and Singapore's Marine Fisheries Research Department.

TTable 5 . Number of research papers publ ished by commodi t y .

Commodity

Tiger shrimp Milkfish Seaweed Grouper Sea bass Catfish Red snapper Tilapia Abalone Others*

Total

Number of Papers Published

Journals

13 5 7 4 5 3 1 2 1 8

49

Proceedings

4 4 2 1 0 1 1 0 0 9

22

Total

17 9 9 5 5 4 2 2 1

17

71

Table 6. Number of research papers presented in local and international scientific meetings.

Commodity

Tiger shrimp Tilapia Mud crab Catfish Milkfish Grouper Abalone Others*

Total

Number

16 4 4 3 2 2 1

11

43

6


.

TTable 7 . Ins t i tu t i ons co l laborat ing w i t h AQD research and deve l opmen t ac t i v i t i e s .

Name of Institution

Australian Center for International Agricultural Research (ACIAR)

European Union (EU)

International Center for Living Aquatic Resources Management (ICLARM)

International Foundation for Science

(IFS)

Japan International Cooperation Agency (JICA)

University of Hohenheim. Germany

Tufts University. U.S.A.

Lonza, LTD. Switzerland

Hamlet Protein A / S . Denmark

International Development Research Centre (IDRC). Canada

Marine Fishery Resources Development and Management Department. SEAFDEC. Malaysia

Marine Fisheries Research Department. SEAFDEC. Singapore

Bureau of Fisheries and Aquatic Resources (BFAR). Philippine Council for Aquatic and Marine Resources Research and Development (PCAMRD). ICLARM

Oplan "Sagip Sugpo" (Shrimp) Task Force composed of BFAR. PCAMRD. U.P. Visayas. Mindanao State University (MSU). Central Luzon State University (CLSU). Negros Prawn Producers Marketing Cooperative. Inc. (NPPMCI).

Research Area

Mud crab research

Ecosystem studies of Laguna de Bay

Institutional arrangements in f isheries co-management

Nutrition and feed development for sea bass and shrimp

Semi-intensive method of seed production in grouper and milkfish: Modeling of eutrophication of Laguna de Bay

Nutrition and feed development for milkfish and shrimp

Genetic diversity of wild and cultured tiger shrimp

Metaldehyde as chemical control of snail pests in milkfish ponds

Hamlet Protein (HP300 and HP960) as protein source for shrimp feed

Genetic diversity in aquaculture

Shrimp culture in mangroves

Antibiotic residue in aquacultured fish

Bangus fry resource assessment of the Philippines

Number of Projects

3

5

1

2

2

2

2

2

1

1

Proposed

(1)

Proposed (1)

1

Rapid assessment of the status of the shrimp industry: verification study of environment-friendly shrimp culture techniques

Tota l =

1

22

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Thesis Research Service Laboratories

As in the past, AQD's research is complemented with thesis work being conducted in its stations and laboratories by AQD staff and other students working for their advanced degrees. As mentioned earlier, several academic institutions are conducting collaborative research with AQD. Staff members and students of these institutions perform their thesis experiments at AQD. During the reporting period, there were eleven AQD studies, which were conducted as thesis research.

The Department maintains six service laboratories: the larval food laboratory, centralized analytical laboratory, feed mill pilot plant, fish health laboratory, and the microtechnique and disease diagnostic laboratory. These facilities continued to serve the Research Division in its requirements for laboratory analyses of research samples and other materials.

Other clientele served by the Service Laboratories included the private sector and some government institutions which are charged at cost. These facilities also provided the laboratories for various training activities of the Department. •

Fish Health Laboratory Microtechnique Laboratory

8

RESEARCH FINDINGS

MARINE AND BRACKISHWATER FISHES

MILKFISH

AQD's research program on milkfish (Chanos chanos) continues to focus on three areas: broodstock development and management, seed production, and culture.

Broodstock Management

This project aims to develop an improved broodstock diet and a reliable transport and handling technique for broodstock and eggs. It also seeks to evaluate the reproductive performance of milkfish broodstock that are kept in various holding facilities.

In 1996 and 1997. feeding studies on vitamin supplementation of broodstock diet were conducted. Initial findings confirmed the benefits of using vitamins as supplement to milkfish broodstock diets. More spawning occurred in milkfish given vitamin C and vitamin E supplements. On the other hand, there were more normal larvae produced from spawns of broodstock fed diets with vitamin C supplement. This ongoing study is analyzing other factors to obtain a complete picture of the effects of dietary vitamin supplements on egg production and quality of milkfish egg.

A second study investigated the effect of adding dexamethasone, a synthetic steroid hormone, to feed of milkfish broodstock a day before fish gets handled or transported from fishponds or sea cages. Initial results show that treatment of feed may not be necessary when milkfish broodstock are handled, confined and transported in chilled water.

Milkfish Seed Production

The project is aimed at refining and improving the existing hatchery

technology for milkfish and determining its economic viability. It also aims to develop criteria for fry quality evaluation.

Several studies were conducted to determine the effects of handling and transport of milkfish eggs and fry. One study indicated that more eggs survived and more larvae hatched when eggs are transported at the late embryonic "eyed" stage than at earlier stages (cleavage, blastula or gastreula). Although there was no significant difference in survival of fry from eggs transported at different embryonic stages, there were fewer abnormalities found in 45-day old fry from eggs transported at the "eyed" stage or as newly hatched larvae. The most common abnormalities found in hatchery-bred milkfish fry occur in the gill region, appearing as cleft branchiostegal membrane (DBM) or deformed opercula.

Egg collection of milkfish at Igang Station. Guimaras.

Milkfish eggs collected at the AQD's Igang Marine Substation are packed for transport to the hatchery at its Tigbauan Main station when these are in an advanced stage of embryonic development (C-shaped embryo stage). During packing and transport, eggs are subjected to varying degrees of mechanical stresses. To simulate these mechanical stressors. C-shaped embryos were subjected to a free fall from varying drop heights of 10. 50.

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RESEARCH FINDINGS AQD 1996-1997 REPORT

.

and 100 centimeters before transport to the hatchery. The results showed that hatching rate of transported eggs were high, and percentage of deformed larvae was low. However, 30 to 40% of the larvae died and most of the 25-day old fry that survived the treatments were deformed.

These results suggest that milkfish eggs are particularly sensitive to mechanical stressors at early larval stages and should be handled and transported during the late embryonic stages to minimize mortality and incidence of abnormalities in the fry. Feeding larvae with live food enriched with highly unsaturated fatty acids (HUFA) and vitamin C however, can lower the incidence of opercular deformity in fry. Growth of larvae fed enriched food was also better.

Hatchery techniques are continuously being refined at AQD not only to improve survival rates of fry but also to lower production costs. A flaked diet for milkfish larvae has been formulated to replace the expensive brine shrimp Artemia used as feed for older larvae. Results of laboratory experiments using this microbound milkfish diet (MBMD) indicated that the diet can be fed together with rotifer to 8-day old larvae and can completely replace Artemia when fed to 15-day old and older larvae. These results have been verified in commercial hatcheries. The feeding scheme using MBMD gave comparable survival and growth rates to the all-live food feeding scheme earlier developed by AQD researchers.

Meanwhile, semi-intensive rearing of milkfish larvae in large tanks is an alternative method of producing fry with minimum inputs. Larvae stocked at 5 to 10/liter are fed copepod nauplii collected from the sea or nearby ponds together with some rotifers until these are able to utilize artificial feed. High survival rates up to 8 0 % and bigger fry were obtained with this method.

AQD researchers, in collaboration with BFAR and ICLARM, also assessed the milkfish fry resources in selected areas. A survey and actual fry collection using a standardized sweeper was conducted among 194 fry gatherers in five selected provinces in the Philippines. The study indicated that the occurrence of milkfish fry was highly seasonal. The peak season lasts for 2-3 months, that is from April to May and may extend to June. Fry prices during these months are usually low due to abundant supply. Fry gatherers devote more time to fry gathering during these peak months. The survey respondents perceived that the production is declining. Similarly, time series data on fry collection gathered from the five selected sites also revealed an apparent decline in production. Pollution, degradation of coastal habitats, overexploitation and decline in sabalo (mother fish) population were perceived by respondents to be the possible causes of the decline.

Milkfish Culture

The project continued to address basic problems in milkfish farming. Most recent studies were on the problem of snail infestation in brackishwater ponds and on the refinement of feeds and feeding management for milkfish.

Studies on the ecology, environmental tolerance, and reproduction of snails (Cerithidea cingulata) in milkfish and shrimp ponds were conducted. The data suggest that the absence of natural competitors and predators and the presence of a rich food supply favor a population explosion of snails in milkfish and shrimp ponds.

Findings also indicate that snails feed the whole day, during low or high tide. Snails taken from a site with fine mud and a thin surface layer of diatoms and 'lablab'1 filaments, all had in their guts a

1 Local name for the mat-like, water surface layer of natural fish food composed of algae, etc.

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Cerithidea cingulata

soft, yellowish-brown 'mush' with no discernible filaments or animal parts, but some fine mineral particles. Snails stocked at 1,200/m2 in ponds with lablab' stayed mostly in the pockets of mud and did not affect lablab' growth. Earlier studies have shown that C. cingulata are deposit-feeders and assimilate both unicellular algae and bacteria. High organic matter in sediments favors the population explosion of snails.

The snails grow, reproduce, and settle in ponds and the surrounding mudflats year round in a closed cycle. They are sexually mature in just over a year, when their size reaches 15-17 millimeters.

Snails are not easily affected by normally occurring fluctuations in dissolved oxygen, salinity, ammonia, pH, desiccation, and sunlight exposure. But experimental data suggest that some environmental factors act together in nature, and these can be used to design effective control measures. For instance.

the studies showed that pond conditions have to be really bad (no oxygen, high ammonia, and high sulfide) for long periods for snails to be killed at all. Also, snails cannot thrive in fresh water and in seawater at salinity levels of 48 -70% ppt. Snails placed under the sun without water and with and without sediment died in two weeks, while those in the shade survived four weeks. High ammonia at high pH can kill snails. Snails stocked 100/liter in static sea water produced 100 ppm ammonia after 11 days. Snails kept in static seawater at different pH for 12 days had 76-96% mortality at pH 3-4 and pH 10-11.

A series of experiments was also conducted to design effective measures against the snail problem in milkfish ponds. META metaldehyde, a biodegradable chemical used to control snails in agricultural fields, was found effective when applied in milkfish ponds at 30 kilograms per hectare. The chemical is applied in pellet form and contains 7.5 to

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20% active ingredient. During the dry season, ponds with snail populations less than 2,000 per square meter required 80 kilograms of metaldehyde per hectare. In the wet season, ponds need 120 kilograms of the chemical. For both seasons, 120 kilograms of metaldehyde proved effective against snails in ponds with over 2,000 snails.

Earlier tests have shown that META metaldehyde did not kill milkfish even when the chemical was applied at concentrations up to 175 kilograms per hectare with the fish exposed to the chemical for 7 days. Thus, to kill snails immediately, the lethal concentration (80-120 kg/ha) of the active ingredient must be applied.

Technical grade (99% pure) metaldehyde was also tested against snails (600/m2) at different salinities in the laboratory. At 20-25 ppt salinity, 30 ppm metaldehyde was lethal to almost all (99%) of the snails after 3 days. However, the chemical was found to be more effective at a higher salinity level of 40-50 ppt than at 5-10 ppt and 20-25 ppt.

Tests were also made on the use of high concentrations of common farm inputs as possible toxicants against snails. Chicken manure, when applied in the pond at 1-100 g/liter, killed 55-71% of the snails in 4-7 days where total ammonia reached 83-139 ppm. Application of commonly used fertilizers ammonium phosphate and urea performed similar effects. Ammonium phosphate at 10-100 g/liter killed 80-100% of the snails in 24 hours, when ammonia was 446-15,000 ppm and oxygen was 5 ppm. Urea at 5-50 g/liter killed nearly all snails in 24 hours when ammonia was 34-1,800 ppm and oxygen was 2-3 ppm. In all these tests, the pH was between 7.2 and 8.2.

Based on the results of the studies, a workable pond management scheme aimed at effectively controlling snail

infestation in milkfish ponds can be recommended.

Meanwhile, as part of a continuing effort to design a cost-effective and environment-friendly diet for milkfish in grow-out ponds, the phosphorous requirement of milkfish was investigated. Diets with 0.85% phosphorous were found to be optimum for growth, survival, and bone and scale mineralization.

Another study examined the effects of salinity and the ratio of natural food (N) to formulated feeds (F) on the growth of milkfish (3.7 grams). The food intake and oxygen consumption of milkfish given three food ratios (75N:25F, 50N:50F, 25N:75F, where the crude protein of the dried combinations were 31, 25, and 14%) at either 15, 25 or 34 ppt) were determined. Results showed that all groups of milkfish had similar oxygen consumption rates of 3.4-3.8 grams oxygen, and daily energy turnover of 66-75 kJ, per kilogram metabolic body weight per day.

Other studies on food and feed intake of milkfish in ponds show that feeding the milkfish early in the morning and at a ration of 3.75% of body weight is wasteful of good quality feeds. The milkfish eat mostly during the later part, around 1100-1500 h and 1600-1800 h. They empty their guts in 6-7 hours. Where natural food is limited, plankton is eaten in the morning and evening but this makes up only a small part of the total intake. Where natural food is abundant, milkfish tend to eat detritus, the decomposed material in the pond, which accounts for 70% of their food intake.

GROUPER

Broodstock Management and Seed Production

The project is aimed at enhancing the egg quality of the grouper (Epinephelus

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coioides) through improved broodstock nutrition and increasing survival of the larvae in the hatchery through improved feeding management, hormonal manipulation and improved culture techniques.

Nutrition and feed studies were conducted. One study found that spawning was not consistent in grouper fed with artificial diet containing different lipid sources or those given fish by-catch (trash fish). However, grouper fed fish by-catch seemed to give better egg production. Both floating eggs and those in the bottom of the water showed similar fatty acid composition although the mean total lipid was higher in floating eggs. In a related experiment, broodstock fed a diet of trash fish mixed with an artificial diet gave a higher number of spawning, more eggs and a higher percentage of good eggs.

Another study found that best growth and survival of grouper fry were obtained in diets containing 42% protein. 10% lipid and a supplementation of 1.0% highly unsaturated fatty acid (HUFA.) Poorest weight gain was observed in the diet with no HUFA supplementation. On the other hand, the diet containing the highest HUFA supplementation produced the lowest survival.

Experiments were also conducted to determine the effects of feeding HUFA-enriched rotifers on the growth and survival of grouper larvae. The first run of the study showed no significant difference in the larvae fed with a HUFA-enriched diet and those fed with other diets. During the second run. survival was significantly higher in fry fed the HUFA-enriched diet than those fed with rotifers reared on the Chlorella algae. On the third run, fry survival was again higher in the HUFA-enriched diet. Growth of the fry did not differ among treatments. Salinity stress tests showed higher survival in larvae fed with the enriched diet and artificial diet.

The semi-intensive method of seed production and the use of thyroid hormones to accelerate metamorphosis in grouper were verified in 10-ton tanks. A daily addition of the thyroxin hormone T3 at 0.01 ppm for 7 days into the rearing tank of 21 -day old grouper larvae previously provided with copepod nauplii and rotifer as early food, advanced full metamorphosis of the larvae characterized by the appearance of their distinctive body coloration.

Meanwhile, another experiment studied how grouper adapt itself to salinity and temperature changes. Twenty-day old larvae, forty-day old larvae and sixty day-old juveniles reared under ambient condition (32 ppt, 26.5-28.5°C) were

Grouper seed production and causes of high mortality on larval stages are major areas of study.

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abruptly transferred to different test salinities and temperature levels. Results showed that after 48 hours of exposure to treatments, survival of the 20-day old larvae was higher at 8 and 18 ppt salinity level than at 32 and 40 ppt regardless of temperature. Survival was also higher at 25"C than at 3 0 C at all salinities. On the other hand, survival of the 40-day old larvae was higher at 30°C than at 25°C regardless of salinity. The survival rates of grouper juveniles were similar in all treatments. Histological preparations for the determination of chloride cell morphology, density, and size are ongoing.

Nursery and Grow-out Culture

The project aims to develop techniques for collection, handling and transport of grouper fry: develop and refine nursery techniques: and to refine grow-out culture techniques with emphasis on feeding management, environmental monitoring and disease prevention.

A study determined the effect of various phospholipid sources of grouper larvae weaning diet on the growth, survival, feed efficiency and fatty acid composition. Preliminary results showed that feeding artificial diet improved weight gain (748-780%) compared to those fed newly-hatched Artemia (445%). Highest weight gain was observed in larvae fed diet supplemented with phospholipid extracted from marine fish egg. However. survival was highest in larvae fed a diet supplemented with newly hatched Artemia while larvae fed a diet with soybean showed the lowest survival.

Successful grouper fry production is hindered by the lack of a standard larval rearing technique that ensures consistent good growth and survival. Larvae are extremely sensitive to stress thus there is a need to know the zootechnical aspects (aeration, light intensity, and green water as medium) in order to develop a standard grouper larviculture technique that will stabilize survival rates.

Because of insufficient supply and high cost of trash fish for grouper, the use of formulated diets is necessary. A study to determine the digestibility of selected local feed ingredients for grouper is ongoing.

RED SNAPPER

Broodstock Development and Seed Production

The project aims to develop an effective and reliable broodstock management and seed production technique for the mangrove red snapper (Lutjanus argentimaculatus). The broodstock management technique will be developed based on data on the red snapper's reproductive biology and through the use of hormonal and nutritional interventions to guarantee the maximum production of highest quality eggs and larvae. Hatchery technology that can hasten metamorphosis and ensure consistent production of fast-growing, disease-resistant and high-survival fry must be generated.

Presently, a breeding protocol is being developed. Egg production estimates of up to 3 million eggs / f emale /spawn and up to

Broodstock of mangrove red snapper matured after 3 years in captivity.

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0.2 million eggs /kg body weight were obtained from induced spawning trials. Both human chorionic gonadotropin (hCG, 1.000 IU /kg body weight) and luteinizing hormone-releasing hormone analogue (100 mg /kg body weight) were equally effective when given as a single injection to mature males and females. The high fecundity implies that a lesser number of broodstock can adequately supply eggs for hatchery operations. Similar egg production estimates were also attained when natural spawning was observed in July to September 1995.

In broodstock development, it was confirmed that sexual maturation is attained at 3 years rearing from fry stage. Previously, the time of sexual maturation in mangrove red snapper was not yet known.

Salinity tolerance tests on eggs and larvae indicated that higher hatching rates and percentage of normal larvae (without deformities) were attained in eggs maintained at 32 ppt or abruptly transferred to 40 ppt than those transferred to lower salinities (8, 16, and 24 ppt). Consistent results were obtained in eggs transferred during the morula, embryonic, or eyed-stage.

Thyroxin or triiodothyronine at 0.01 ppm was equally effective in enhancing metamorphosis of 3-week old larvae after one week of treatment. None of the larvae in the control and thiourea-treated groups metamorphosed in the same period.

Initial results indicated increased larval survival at low stocking densities. In the first trial, larvae stocked at 1,000 individuals (ind)/ton initially in 1-ton tanks for one week and at 3-ton tanks thereafter survived better (20.5%) after 5 weeks than those stocked at 2,000 (3%) and 3,000 (6.1%) ind/ ton. In the second trial, larvae stocked at 100 ind/ ton in 3-ton tanks had higher survival rates (73.27%) after 5 weeks than those stocked at 200 (55.06%) and 300 (37.46%) ind/ ton.

Nursery and Grow-out Culture

The project aims at developing nursery and grow-out culture techniques for red snapper: determining the nutritional requirements of snapper juveniles: and developing practical diets for nursery and grow-out phases.

Currently, preparations are being made for experiments on development of practical diets. Hatchery-produced juveniles reared in A Q D tanks were acclimatized to pelleted feeds. Two fish sizes were maintained for experiments, which will commence, in early 1998.

SEABASS Seed Production and Culture

The project is aimed at verifying the use of SEAFDEC-formulated practical diets for grow-out culture and at assessing the economics of sea bass (Lates calcarifer) culture using these formulations. In addition, it intends to develop proper

Studies on seabass seed production and culture continue as a major AQD research activity.

feeding management and to evaluate the use of immune modifiers in enhancing non-specific immune response in fish using sea bass as model fish.

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Gut content analysis of seabass juveniles.

Methods to improve embryonic and larval survival may be formulated if egg quality parameters are identified. Using the sea bass as a model, morphometric, histological, and biochemical analyses are being conducted on egg samples collected from induced spawns from May to October 1997.

Fertilization was zero in May and in October. Eggs and oil globule diameters (0.72-0.80 and 0.23-0.31 mm, respectively) showed no specific trend within the season or between consecutive spawns. Egg wet and dry weights (0.18-0.32 and 0.02-0.03 mg, respectively) also showed no trend.

In fish that had two consecutive spawning, eggs during the second spawn had a significantly higher percentage of normally dividing and developing embryos. On the other hand the percentage of normal larvae and total length and oil globule diameter of newly hatched larvae were not significantly different in the first and second spawns. Analyses of lipids, fatty acids and total amino acids are ongoing.

The possible utilization of Diaphanosoma celebensis as partial or complete substitute for Artemia sp. as food for sea bass larvae was studied. Sea bass larvae (15-day old) were fed with Diaphanosoma alone, Artemia alone, or a combination of these two larval food types. Larvae fed with Diaphanosoma alone or the combination of Diaphanosoma and Artemia sp. were reared at 15 ppt salinity level while those fed with Artemia alone were reared at 32 ppt.

Results showed that after 15 days of rearing, survival was high (95-99%), and apparent loss due to cannibalism (0.2-4.1%) was low in all treatments and differences were not significant. However, those fed Artemia alone or the combination of Artemia and Diaphanosoma had significantly higher specific growth rates (18.7-19.1% per day) than those fed Diaphanosoma alone (16.3% per day). Furthermore, although Diaphanosoma had higher dietary crude protein and fat, the percentages of n-3 highly unsaturated fatty acids (particularly 20:5n3 and 22:6n3, eicosapentaenoic acid and

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docosahexaenoic acid, respectively) of Artemia were higher. These results indicate that Diaphanosoma. can be a potential partial substitute for Artemia in the larval rearing of sea bass.

Optimizing growth and minimizing food wastage are some of the means to improve growth and survival of juveniles in the nursery. A parameter frequently measured to characterize factors affecting the digestion in fish is the rate of gut evacuation (i.e., passage of food along the gut per unit time). This parameter is useful in estimating food consumption and food conversion rates.

In the study on the digestion and gut evacuation rates in the juvenile sea bass, results showed that fish fed enriched Artemia had an average gastric digestion time of approximately 1 hour. Those fed non-enriched Artemia and wild copepods had an average gastric digestion time of 4.5 hours. Analysis of stomach contents one hour after the onset of feeding showed an average ratio of intact vs partially digested foods as 4.3 (enriched Artemia-fed), 64.5 (non-enriched Artemia fed), and 3.1 (copepod-fed). It was also observed that sea bass juveniles with a length of 5.8 mm can ingest as much as four live tilapia or goby fry in the first hour of feeding. The average gastric digestion time was approximately 4.5 hours. Further analyses are being done to describe the process and instantaneous rates of gut evacuation in sea bass juveniles.

Studies were also conducted on fish health. One study was conducted on the effect of possible immune modifiers on the nonspecific immune response in sea bass. This was assessed by measurement of plasma lysozyme level and phagocytic ability of leukocytes.

Findings suggest that a drop in plasma lysozyme levels of 20% occurred a day after handling and transfer of sea bass to smaller containers. After 5 days, lysozyme

levels were still 10% less than that of the control group despite the resumption of feeding. After 10 days, the lysozyme levels were similar with the control.

The effect of different doses of levamisole on sea bass plasma lysozyme levels was also studied by immersing the fish for one hour in a bath containing either 0 ppm (control), 1.5 ppm, 3.75 ppm or 6.5 ppm levamisole. At 48 hr post-immersion, only fish in 3.75 ppm showed a significant increase in plasma lysozyme level compared with the control. In a time course study, a one-hour immersion of juveniles in 3.75 ppm levamisole brought plasma lysozyme values to 30% higher than the control at Day 2 post immersion; significantly high level (20% above control) was maintained until Day 5. However, at Day 10, lysozyme level was no longer significantly different from the control and by Day 17, lysozyme level dropped by 12% from control value.

Exposure of sea bass for one hour to formalin (100 and 300 ppm) and copper sulfate (50 and 100 ppm) neither increased nor decreased significantly their plasma lysozyme levels. Preliminary results showed that aluminum chloride (50 ppm) slightly increased while zinc chloride (50 ppm) slightly decreased plasma lysozyme levels.

Nutrition and feed development for sea bass is also a major thrust. To develop a cost-effective practical feed aimed at replacing the use of fish by-catch in sea bass culture, studies were conducted on the essential amino acid requirements of sea bass juveniles. Information obtained from these studies were used to design test diets based on indigenous and inexpensive ingredients. The requirements for isoleucine and valine were also studied in 1997.

Based on nutrient requirements of sea bass, a practical diet was formulated using indigenous ingredients. The most cost-effective diet resulting from a

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previous screening was tested in fish in cages and ponds. Locally available protein sources were used: fish meal, shrimp head meal, scrap squid meal, blood meal, poultry feather meal, leaf meals, soybean meal, and mungbean meal. The diets which contained combinations of animal and vegetable protein sources had essential amino acid compositions similar or close to that of sea bass muscle tissue. Crude protein was 4 3 % and fat was 10%.

In floating net cages, sea bass with initial average body weight of 5 g were stocked at 10 or 15 fish per cubic meter. Four formulated diets containing kangkong2 and ipil-ipil leaf meals and a control diet were fed ad libitum to sea bass for 16 weeks. The control diet seemed to promote the best growth, survival and feed efficiency ratio but the diets containing kangkong or ipil-ipil were more cost effective.

Results showed that the apparent protein digestibility (APD) values for diets containing dehulled cowpea (92.88%), dehulled mungbean (92.24%) and boiled cowpea (92.59%) were significantly higher than those of unprocessed cowpea (91.17%). boiled mungbean (90.33%) and unprocessed mungbean (91.07%) -based diets. However these were comparable with that of the control diet containing defatted soybean meal (94.12%).

On the other hand, processing of legumes had no significant effect on the growth performance of sea bass. The percentage weight gain (1445.3%) and specific growth rate (4.4%/day) of control diet fed-fish were higher than those given test diets (1216%-1286%: 4.2%-4.3%/day) : but the differences were not statistically significant. The feed conversion ratio for all diets ranged from 1.14-1.21.

The same diets were tested in brackishwater ponds (10 ppt). Sea bass were initially stocked at 4 fishes per square meter. Stocking density was reduced to 1 per square meter when the fish became bigger. The same feeding regime was applied. Results indicated that sea bass generally grew better in floating net cages than in ponds. Findings also showed that locally available agricultural and marine by-products could be used in feeds for juvenile sea bass and that sea bass reared in floating cages and in brackishwater ponds could require lower amounts of added vitamins and minerals in the feed. Finally, diets containing kangkong or ipil-ipil were found more cost-effective.

Meanwhile, white cowpea and green mungbean were selected based on in vitro protein digestibility. The legumes were boiled, dehulled. and incorporated in the sea bass diet for in vivo digestibility and growth experiments.

MARINE ORNAMENTAL FISH

Breeding and Seed Production

Increasing demand for exotic fishes for the marine ornamental fish trade has resulted in heavy exploitation of many coral reef species and degradation of their habitats. To reduce the impact on wild populations and their ecosystem.

2 Philippine term for Ipomoea acquatica. Studies on ornamental fish are geared to tap its potential for the export market.

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sustainable aquaculture of some important species must be developed.

The project initially aims to generate technology for breeding, hatchery production and juvenile rearing of seahorses (Hippocampus spp.) blue tang (Paracanthurus hepatus), and panther grouper (Cromileptes altivelis). Current studies focus on the biology, broodstock development and seed production of seahorses, tentatively identified as Hippocampus histrix and H. erectus or H. kuda of the family Syngnathidae.

In 1996, an initial stock of 32 pairs of the relatively smaller (3-9 g) and spiny seahorse H. histrix and 18 pairs of the lined seahorse (H. erectus or H. kuda, 10-22 g) were transported from an aquarium fish exporter facility in Manila to the SEAFDEC/AQD Tigbauan Main Station in Iloilo. At least 15 males were pregnant during transport and gave birth within nine days. However, most of the newly born juveniles were small, weak, and lightly pigmented, indicating premature birth. About 78% of the broodstock died within three months, most probably due to stress brought about by transport, hatchery confinement and parturition. Rematuration and breeding in captivity were observed three months after transport.

Breeding and seed production trials in 1997 have produced about 265 hatchery-reared H. histrix broodstock. 281 second-generation offspring from 17 breeders, and a few (39) third-generation offspring. Three pairs of wild lined seahorses have produced about 58 potential breeders and 42 second-generation juveniles. While established breeding pairs can produce broods every two weeks with intermittent gaps year-round, brood size and viability were highly variable. Further investigation on alternative food organisms, a suitable feeding scheme, and improved water management for broodstock and juveniles will be undertaken to enhance brood viability.

Rabbit fish (Siganus guttatus).

RABBITFISH

Seed Production and Growth Enhancement

The project aims to increase survival of larvae in the hatchery through improved feeding management and hormonal intervention, and to gather information on growth regulation in rabbitfish (Siganus guttatus) juveniles.

Brain and pituitary samples were collected in order to isolate, purify, and characterize growth hormone and other neuroendocrine factors of this species. These purified hormones will be used in studies aimed at understanding growth regulation and develop measures to hasten growth in this slow-growing fish. •

FRESHWATER FISHES

TILAPIA

Selective Breeding and Broodstock Management

The tilapias (Oreochromis niloticus) have become the focus of several genetic

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Tilapia progeny testing experimental set up in Tanay, Rizal.

improvement programs in the Philippines and other countries in Southeast Asia. Most of these are centralized, large-scale and quite expensive. Fish farmers depend on dispersal centers for improved fingerlings. A viable option for fish farmers is to engage in small-farm selection as an alternative to large-scale projects and make their fish economically competitive. Thus this project aims to develop appropriate and cheap selection procedures; develop a desirable red tilapia; and explore the potential of farmer-based participatory research on breed selection.

One generation of mass selection based on the collimation procedure (early culling of large fry) was applied on Nile tilapia in net cages in Laguna de Bay, Philippines. The selection resulted in a

significant positive response of 3% as measured by the percent differences of the lengths of selected offspring from the control offspring. This represents a projected 34% gain over 5 years in Laguna de Bay cage culture.

This modified mass selection has been applied on the second generation breeders. The progenies are scheduled for progeny testing in July 1998. This study has shown that collimated mass selection is simple enough to be a low-cost feature of artisanal farming practice, and is capable of generating economically significant improvement of a small population after a single generation. Even a small response of 3% should be considered economically important to the tilapia industry.

Fin-clipping tilapia fingerling prior to progeny testing

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This mass selection procedure is now being pilot-tested in collaboration with two commercial tilapia hatchery farms in the Philippines. The objective of this collaborative farmer participatory research on breed selection is to help farmers develop their own tilapia broodstock. In the Calauan Tilapia Hatchery Farm in Laguna province, the first and second directional selection applied on two "local" Nile tilapia strains were completed. The fry to be produced from the select breeders and control breeders will be used for the scheduled progeny testing. Likewise, in the Silangan Venture Farm in Tanay, Rizal province, the first and second directional selection applied on another "local" Nile tilapia strain were completed. The fry to be produced will be used for progeny testing.

An important implication of this collaborative project with farmers is that fish farmers would have more control over their choice of good quality spawners. They can design simple and cheap selection procedures using their own tilapia breeds. Dependence on a "franchise-dealer" type of seed production will be minimized and a socio-economically self-sustaining genetic conservation will also be achieved.

In another study to develop high yield red tilapia strain through introgressive hybridization with Nile tilapia. four distinct phenotypes were produced from the progenies of the F2 mass spawned introgressed red tilapia. The color types are bright red orange, red orange with blotches, pale pink and the normal grey color. One generation of introgression resulted in a significant response of 2.5% as measured by the percent differences of the lengths of introgressed red orange offspring from the normal red tilapia (progenies of the founder population of red tilapia). After several generations of introgression, a directional size-specific mass selection through early culling of large fry was applied on the F4 introgressed red orange tilapia. This was

aimed at selecting for a fast growing red tilapia strain. The progenies of the select breeders and the control breeders are scheduled for progeny testing in January 1998.

In another study, growth and survival of five Asian red tilapia strains in brackishwater and seawater were assessed. This study showed that mean specific growth rates of the fish indicated significant differences among the strains reared in seawater. The Philippine red tilapia strain grew best in seawater while the Thailand strain performed well in brackishwater. In the Philippines, red tilapias are farmed in intensive freshwater culture systems by few aquaculturists. Results of this study indicate that some Asian red tilapia strains can be developed for culture in more sustainable brackish and seawater systems.

CATFISH

Breeding and Seed Production

The breeding and seed production project on the Asian catfish (Clarias macrocephalus) is designed to prevent its permanent loss as fish for food. This species is getting scarce in its natural freshwater environment in the Philippines. Studies are conducted on

Catfish research aims to prevent its permanent loss as food fish.

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breeding, hatchery and nursery practices aimed at mass production of catfish fry.

In 1996-1997, studies on breeding focused on methods to minimize the existing practice of sacrificing males during artificial fertilization. Improvement of hatching efficiency of the eggs, as well as hatchery techniques developed in the previous years were carried out to produce fry for the nursery phase. Fingerlings were also produced in concrete tanks and net cages installed in ponds.

Captive males do not release milt (a hydrated suspension of sperm) naturally to fertilize the eggs. Hence, studies were conducted to induce milt release using hormones, and to maximize the use of milt by dilution.

While sperm production increased after hormone injection, milt was not released in treated males. Another study then used an artificial seminal plasma (ASP), prepared following the composition of the seminal fluid, to dilute the milt. Results showed that catfish sperm became motile upon activation when the milt was diluted with the ASP at 1:100 -1:200, but were irreversibly inactivated at higher ratios of 1:300 - 1:1,000. High fertilization and hatching rates were observed when milt diluted with catfish ASP at a ratio of 1:100 was activated with a 0.6% salt solution to fertilize 5 or 10 g of eggs.

To improve hatching efficiency of catfish eggs, experiments were conducted to determine the optimum stocking density, suitable containers, and optimum water hardness during egg incubation. It was shown that hatching rates were not significantly affected by stocking densities tested and type of incubators used. Findings suggest that eggs can be incubated at stocking densities up to 4,000 eggs/ l i ter using an inexpensive plastic basin as incubator.

Total water hardness during incubation was found to affect hatching rates. Hatching rates were significantly higher when catfish eggs were incubated in water that contained a total hardness of 0-100 ppm than when incubated in water of higher total water hardness (200 and 400 ppm).

In 1997. a study on catfish fingerling production in concrete tanks and net cages installed in ponds was conducted. At stocking densities of 200 and 300 fry per square meter, growth of catfish fry after 28 days of rearing was faster in ponds than in tanks. Survival rates however, were higher in tanks than in ponds. These results showed that size and survival rates were more uniform when catfish fry were grown in tanks than in net cages installed in ponds.

CARP

Broodstock Management and Genetic Improvement

The project aims at developing a sustainable and efficient technique for bighead carp (Aristichthys nobilis) broodstock development using its innate compensatory growth characteristic. It will also investigate the genetic structure of bighead carp population and correlate genetic diversity with sex ratio and

Bighead carp (Aristichthys nobilis).

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number of breeders used for spawning in different carp hatcheries.

The commercial production of bighead carp broodstock is hampered by the shortage of quality broodstock. There is a need to explore a cost-effective broodstock development strategy before any stock improvement program can be initiated. Likewise, there is also a need to study the genetic structure of the population. These will be the basis for proper broodstock management and a sound genetic improvement program.

In response to the shortage of quality broodstock and the need for a cost-effective broodstock development strategy, this project started a study on growth retardation of carp stocked in cages under natural lake conditions. Results indicated that after six months under natural lake conditions, fish grown in the cages attained higher weights than those cultured in restricted tanks. Average body weight per fish was about 1 to 1.5 kilos. Meanwhile, the stunted fish were subsequently reared in cages and after two months of rearing, an average weight range of 17.7 to 28.6 grams was attained from an initial weight range of 3.5 to 3.7 grams. •

CRUSTACEANS

GIANT TIGER SHRIMP

Shrimp Broodstock Development

This project focuses on establishing a reliable and sustainable supply of good quality captive shrimp (Penaeus monodon) broodstock for the hatchery.

An analysis of the genetic diversity in wild and cultured tiger shrimp using the random amplified polymorphic DNA (RAPD) technique was done in collaboration with Tufts University. USA. Wild and cultured samples from various regions were collected for DNA isolation.

Shrimp broodstock technology development is another important continuing study

Preliminary results showed that samples obtained from the wild were relatively more polymorphic than the cultured samples.

Meanwhile, studies on the reproductive performance of pond-reared shrimp were conducted. A feeding experiment showed that shrimps given formulated diets with 50 ppm astaxanthin (a red carotenoid) can significantly improve egg production (2,276 eggs / g female) compared with shrimps fed diets containing 2.3, 20 or 100 ppm astaxanthin supplement, or those fed all natural food (squid and mussel). However, hatching rates were similar in all dietary treatments. Broodstock fed all natural food matured and spawned more often than those fed diets with astaxanthin supplement.

In another development, sperm quality of shrimps transferred from pond to tank seemed to decline after 35 days in the tank. More abnormal sperm were

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observed in ablated than in unablated males although their respective sperm counts did not differ. Sperm quality seemed to improve in males with more than 65 g body weight.

Refinement of Shrimp Culture System

This project aims to develop ecologically sound and sustainable pond grow-out management methods that optimize the production capacity of various shrimp culture systems. During 1996 and 1997, nine studies were conducted. These centered mainly on improvements on artificial diets for shrimp grow-out culture, salinity tolerance in shrimp, and on environmental impact of semi-intensive shrimp culture.

Efforts to improve artificial diets were aimed at completing the amino acid requirement of shrimp. Preliminary data on phenylalanine and histidine amino acid requirements have been gathered while the study on tryptophan is ongoing. In the feeding experiments, a phenylalanine supplement of 1.22% to shrimp artificial diet gave the highest weight gain while a 0.87% histidine supplement similarly achieved the same result.

Two protein sources were evaluated for use in shrimp juvenile diets: HP 300 (a processed soya product containing 5 5 % crude protein) and HP 960 (HP 300 plus fish soluble products containing 6 0 % crude protein). Feeding tests show that HP 300 can be used as a protein substitute for fish meal (6 and 12%), soybean meal (4 and 8%), and shrimp head meal (5%) because growth of shrimps fed these diets were better compared with those given SEAFDEC-formulated diet and a commercial feed. At 4% replacement of soybean meal with HP 960, growth of test shrimps was comparably lower than those obtained for HP 300. However, growth was still comparable with shrimps given commercial feed.

Cost-effective shrimp diets are likewise being developed with sufficient dietary energy from the non-protein energy sources so that protein will be used solely for growth. Results of a study showed that shrimp diet must be formulated to contain 4 1 % protein and a 1:1 ratio of lipid and carbohydrate as energy source for optimum growth and feed efficiency.

A study was also conducted to determine the phosphorous requirement of shrimp juveniles. Based on a 90-day feeding test using diets with various phosphorous levels, shrimps best gained body weight when given diets supplemented with 0 .5% phosphorous.

The effects of different processing conditions (temperature and time of heating) on the urease activity (UA) levels in soybean meal as well as the resulting effects on the nutritional quality of feeds using growth and survival index of shrimp juveniles were determined. The most adequate heat treatment for soybean meal in order to be an effective feed ingredient is at 120°C for 20 minutes. Growth and survival were highest when shrimps were given diets with soybean meal processed under this condition. At this treatment, urease activity level was minimal (0-0.32 ppm) compared to unprocessed soybean meal (20-25 ppm).

Meanwhile, the newly implemented study on evaluation of impact of semi-intensive shrimp culture on the environment will monitor effects of excess feeds and animal waste generated by the system.

Shrimp Health Management

The project applies the epidemiological approach in defining disease problems in shrimp culture and aims to identify and develop environmentally sound methods of health maintenance, prevention and treatment.

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Shrimp samples were collected to determine the prevalence of viruses infecting shrimps and to examine how these are transmitted.

Results show that the dominant virus infecting shrimp postlarvae are monodon baculovirus (MBV) and hepatopancreatic parvo-like virus (HPV) as detected by light microscopy with prevalence rates of 32% and 30%, respectively. Among pond-reared and wild-caught broodstock the following viruses were detected: MBV. HPV, infectious hypodermal and hematopoietic necrosis virus (IHHNV), and lymphoid organ vacuolization virus (LOW) . Transmission experiments showed that the disease develops in healthy postlarvae by feeding them with HPV-infected shrimp carcasses. The study also found that mortality and effects of viruses were significant in shrimps stocked at 8 postlarvae/liter compared to those stocked at a lower density of 5 postlarvae/liter.

To understand the course of luminescent vibriosis infection in grow-out farms, a study to compare the qualitative and quantitative bacterial flora of hatchery-reared and wild-caught shrimp postlarvae was conducted. Results showed that hatchery-reared postlarvae harbor numerous potentially pathogenic vibrios in their gut. including luminescent strains of up to 2.3 x 103 colony forming uni ts / postlarva. A relatively lower count of up to 5 x 101 colony forming units/postlarva of luminescent colonies was obtained in wild-caught postlarvae. More samples from the wild need to be processed for comparison. Antimicrobial sensitivity tests using disc diffusion method showed significant resistance to chloramphenicol and oxytetracycline among isolates from hatchery-reared postlarvae (33 and 44%. respectively) compared to bacteria from wild postlarvae (3 and 6%) and from nearshore seawater (0 and 12%).

Meanwhile, a study to produce antiserum for rapid diagnosis of the shrimp vibriosis disease was conducted.

Two luminous bacterial isolates from near-shore seawater and two isolates from adult shrimp were chosen for the study. These were prepared as formalinized antigens and injected into rabbits for antisera production. An antiserum against a luminous bacterial strain from near-shore seawater exhibited a titer of 1.024 after the 5th booster injection. However, antigen from bacteria obtained in adult shrimp produced a low titer of 32 after the 6"' booster injection.

MUD CRAB

Broodstock, Seed Production and Grow-out

The research activities on broodstock development, larval rearing, nursery and grow-out of the mud crab Scylla serrata were aimed at developing sound technologies to promote consistent spawning and hatching of good quality larvae, increase survival and production of crablets, and improve pond yield.

Labeling for proper identification and monitoring of mudcrab.

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An appropriate technique to enhance maturation for mud crab using local materials was developed at AQD. Tanks were provided with sand substrate and a shelter for each female. When held in this maturation system, mud crabs fed artificial diets mixed with natural food gave the highest number of spawning, number of eggs, egg fertilization rate, larval production and quality, and broodstock survival. This suggests that artificial diet as supplement to natural food for mud crab broodstock promotes more consistent spawning and hatching of good quality larvae.

In another study, supplementation of natural food with artificial diet improved the survival of crab larvae and reduced dependence on natural food. Mass production runs using the best diet treatments are presently being carried out.

The major morphological changes found during larval development in mud crab (zoeae to megalopa) were observed through light and electron microscopy. These changes imply that complex food types may be suitable only at later stages. Different larval stages have preference for various food items and pulse-feeding is possible in the megalopa stage.

Studies on megalopa rearing focused on feeds, influence of various shelters, and stocking density on behavior, survival and growth of megalopa and juvenile crabs.

Survival and growth of megalopa were compared using a SEAFDEC-formulated larval diet, Artemia or various unprocessed natural food such as squid, trash fish, and mussel. Results showed no significant differences in survival rates among crabs fed various food items. Weight gain was significantly higher in crabs fed trash fish compared with those fed other food items.

It was shown in another study that stocking of megalopa directly in "hapa" nets3 installed in nursery ponds is feasible. The study will be replicated over time.

To minimize cannibalism among mud crab juveniles, experiments were conducted to determine shelter and substrate preferences of different size classes of crabs. Based on the results, gravel may be used to replace mud (clay soil) as substrate for rearing smaller juveniles, while sand may be used for rearing larger juveniles. The study further showed that the larger juveniles tended to use the net shelter more than the in-star, 10-day, and 15-day old crabs.

An experiment was conducted to determine the response of either all-male or all-female crabs to different diets (vitamin and mineral-supplemented diet, non-supplemented diet, fish by-catch) during culture in ponds. Results showed that while male crabs were significantly heavier than female crabs, their specific growth rate (SGR), feed conversion ratio (FCR), survival and production were not significantly different from each other. Regardless of sex, crabs fed fish by-catch were significantly heavier than those fed with non-supplemented feed. However, crab length, width, SGR, FCR, survival, and production were not significantly different in all treatments. Further, the economic viability of using a diet without vitamin and mineral supplements was comparable with that of a complete diet having an ROI of over 50%. Cheap pelletized feed could therefore be used, thus saving on feed cost, cost of storage equipment, and expenses on electricity. •

3 Filipino term for fine-meshed nylon net, much similar to the common mosquito net, used in an inverted position as enclosure for the aquacultured animal.

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AQD has successfully bred abalone in captivity.

MOLLUSCS

Broodstock Management, Seed Production and Grow-out Culture

of the Tropical Abalone

AQD's thrust in this project is the development of technologies for mass production of seed stock to enhance dwindling natural stocks of the tropical (donkey's ear) abalone (Haliotis asinina).

Specifically, the project aims to increase survival of abalone juveniles through refinement of the diatom culture system, and develop appropriate nursery rearing techniques that include artificial feeding schemes and stocking density.

Coastal aquaculture techniques such as cage culture of marketable-size abalone was also conducted.

In one study, the effect of stocking densities on the growth and survival of postlarval abalone reared with three different feeding conditions were investigated. Results showed that about

4,200 early juveniles were harvested from initial stocking densities of 150,000 to 180,000 larvae. Sixty percent of the harvested juveniles averaged more than 5 millimeters in shell length.

There seemed to be no differences in growth and survival of abalone juveniles reared with different feeding schemes, i.e., continuous fertilization of diatoms, diatom slurry supplementation or their combination. A major problem encountered in these rearing trials was the low larval settlement on the artificial substrate using the vertically suspended corrugated PVC plates. This led to a very low survival rate at harvest, with only about 105-1.120 abalones per one-ton tank. However, there were more survivors at the lower stocking density of 100 larvae per liter.

Meanwhile, another experiment used fertilizer to hasten growth of epiphytic diatoms, a natural food of abalone. Results showed that diatom slurries (75% Navicula, 22% blue-green algae, and 3% Nitzschia) with cell densities of 30x 103

cells per square cm can reach the exponential growth phase of 1.6 to 3.0x105 cells per square cm in 14 days. This was achieved when a commercial grade fertilizer mixed with sodium metasilicate was used and the cultures were placed under direct sunlight. In contrast, cultures placed indoors reached exponential phase in 50 days.

A study investigated the development of a practical feed as an alternative to seaweed. While seaweed is the natural diet of abalone in the wild, a feeding experiment showed that abalone juveniles fed the diet containing 3 2 % crude protein and 3.09 kcal per kg ME gained the most weight (341%) and had the highest specific growth rate (1.78% per day) than those fed the seaweed Gracilariopsis bailinae with 17% protein. Feed conversion ratio and protein efficiency ratio of the artificial diet ranged 1.5-2.3 and 9-11 and were much higher than the

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ratios for seaweed. Survival of the juveniles was generally high (75-100%) regardless of treatment.

The effects of photoperiod on food consumption, growth and survival of early juveniles are also currently being investigated. This study theorizes that since young abalones move and feed more during the night, long dark periods may encourage higher food consumption, and thus enhance growth and survival of the abalone.

Larvae fed a mixed diet of Isochrysis galbana and Chaetoceros calcitrans had the highest survival rate of 12%. However, this was not significantly different when using monoalgal species I. galbana (10.4%), C. calcitrans (8.7%), or mixed diet of I. galbana and T. tetrahele (8.7%). The highest growth increment in terms of shell height was attained in larvae given either Tetraselmis tetrahele or I. galbana as sole feed. The lowest survival rate was observed in larvae fed mixed diet of T. tetrahele and C. calcitrans.

To determine the optimum population that would produce a better and profitable harvest of marketable size abalones, experiments were conducted on stocking densities in floating cages. Results reveal that both small (15-20 mm) and large (35-40 mm) abalone juveniles stocked at 113 individuals or less per square meter grew better than those stocked at higher densities of 175, 338 and 450. These higher stocking densities restricted movement and feeding of the abalone. Moreover, it was observed that the larger-size abalone juveniles converted their feed into more flesh than did the smaller juveniles. Survival of the abalone was not affected by increased stocking densities.

Broodstock experiments using varying algal densities as food were also conducted. Tank-reared broodstock fed a high-density mixed diet of /. galbana (150,000 cel ls /ml ) and T. tetrahele (50,000 cells/ml) developed much better gonads compared with broodstock fed low algal density diet (50,000 cel ls /ml each of /. galbana and T. tetrahele) and those of the river-reared broodstock in the months of June-September, when plankton population in the river was at the lowest (100-700 cells/ml).

About 4 0 % of the tank-reared broodstock had ripe ovaries during the second to the fourth month of culture, with gonadosomatic index (GSI) of 300-410. However, during the months of

Studies on Window-Pane Shell

The mollusc research project also includes studies on the window pane shell Placuna placenta.

Growth and survival of the window-pane shell (Placuna placenta) larvae reared at different water salinity levels and fed different microalgal diets were determined. Survival until metamorphosis was observed in salinities 16-34 ppt. However, settlement was first observed on day 14 in salinities 22-34 ppt when larval shell length of 220 mm was reached. A highest survival rate of 12.6% was obtained in 34 ppt. Window pane shell (Placuna placenta).

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October-March, the river-reared broodstock showed consistently high GSI value (340-450). Fifty percent of these had ripe ovaries. The high GSI value was attributed to the abundance of multi-species plankton (400-5,700 cells/ml) during these culture months.

Broodstock were then induced to spawn by injection with serotonin or exposure to ultraviolet light-irradiated seawater. The tank-reared broodstock fed with high algal density mixed diets spawned less than 100,000 eggs per female. On the other hand, river-reared broodstock spawned 295,000-2.8 million eggs. Consequently, natural spawning was observed in the river as indicated by spats settled on artificial substrates. Thousands of P. placenta were also collected from a nearby prawn farm. •

SEAWEED

Monoculture of Kappaphycus and Polyculture of Gracilaria

and Gracilariopsis

This project aims to develop culture techniques for seaweed along coastal areas, evaluate finfish-seaweed culture, and test the efficiency of seaweed in serving as biological filter of waste and polluting products of intensive shrimp production.

In studies on seaweed culture, an experiment found that both brown and green strains of Kappaphycus alvarezii can be grown commercially in 60 days. Within this period, both strains showed faster growth and high biomass production. This can be achieved by using hanging polyethylene ropes where the seaweed can grow on or a combination of the hanging line and fixed-bottom line. An investment cost of US$255290 4 per

US$1 = 38 Philippine pesos (PHP)

Fixed bottom line-method of farming Kappaphycus.

hectare can bring back revenues of US$2,685-6,090 per hectare.

Another study revealed that three species of seaweed collected from the sea and grown in tanks at different salinity levels had differing external appearance, growth and agar properties. Likewise, each species could grow well under a wide range of salinity levels. Results show that Gracilaria firma grows best in marine waters, while G. changii and G. tenuistipitata are best-suited to brackishwater cultivation preferably pond, estuarine and discharge canal culture.

In addition to the culture studies, a research study showed that seaweed served as a biological filter for nutrients and heavy metals in shrimp aquaculture. The seaweed Gracilariopsis bailinae. when grown at the same time with shrimp in tanks, was found to improve the water quality because of lowered ammonia,

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nitrite, nitrate and phosphorous levels. The seaweed absorbed the excess ammonia and nitrite in semi-intensive culture of shrimps.

The same seaweed when grown with shrimps under intensive culture in ponds gave initial promising results. There was a consistent pattern of lower concentrations of ammonia, nitrite and phosphorous in ponds with shrimps and seaweed compared with shrimps cultured alone. Also, higher survival rate and total biomass of shrimp cultured with seaweed were obtained at harvest time. While the shrimps cultured alone had heavier weights, they suffered from diseases, which resulted in lesser total biomass. These diseases were not observed in shrimps cultured with seaweed. In the meantime, more replications of the study are to be conducted to achieve more conclusive results.

Meanwhile, an ongoing study seeks to understand how seaweed can reduce heavy metal pollutants of natural aquatic environments. Previous information shows that seaweed are able to synthesize metal-binding proteins which help transport metals across cell membranes. Expected results of this study have great potential in current efforts aimed at regulating environmental pollution and the recovery of useful metals from nature.

The natural seaweed products carageenan and agar were also studied. Best carageenan properties (yield, gel strength, viscosity, gelling and melting temperatures) of the green and brown strains of K. alvarezii were obtained when the seaweed were grown in the combined hanging line and fixed-bottom line compared with those cultured in either method. However, both strains were comparable in terms of yield and gel properties. Carageenan properties were also found to vary with the season where these peak during the dry season (October-April).

G. changii, G. firma and G. tenuistipitata demonstrated different agar properties when grown in tanks at different salinity levels. Agar properties of G. changii and G. firma are suitable for food applications while those of G. tenuistipitata have potential for microbiological or pharmaceutical applications.

The agarose properties of G. bailinae collected from wild populations showed seasonality with highest gel strength recorded in April and June with a corresponding lowest record in December. However, this was the reverse for agarose yield. Water salinity was the only factor found to be positively correlated with agarose properties. •

ENVIRONMENT, ECOLOGY, AND OTHER STUDIES

LAGUNA DE BAY, PHILIPPINES: AN ECOSYSTEM APPROACH

TO SUSTAINABLE MANAGEMENT

This ongoing project is a collaborative effort of A Q D with four European and two Philippine research institutions.

It has the following objectives: 1) obtain data for construction, validation and calibration of an ecological model, 2) determine changes in water quality, nutrients and plankton in the lake, 3) determine the food uptake by cultured and wild fish, 4) establish food webs, and 5) investigate other data needed to fill in gaps of information.

Project activities in 1996 and 1997 were varied. These were ultimately aimed at obtaining information on the biological processes occurring in Laguna de Bay that are needed in the formulation of an ecological model being developed.

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Hartmut Richter, a German visiting researcher analyzing water samples in the field.

Physico-chemical and Biological Aspects

Mass fish kills usually following plankton die-off did not occur partly because of the timely northeasterly winds that influenced mixing of the lake water. The 1996 monitoring of Laguna de Bay showed no significant differences among the 3 study stations on a monthly basis for most of the water quality parameters measured. Saltwater intrusion did not occur in the summer months of 1996. Hence, water was generally turbid throughout the year except during calm weather such as in September. This allowed some degree of clearing of the lake water followed by occurrence of plankton blooms.

Laguna de Bay was not directly affected by typhoons in 1996: thus, the relatively low water level of the lake in 1996 allowed the backflow of saltwater through the Pasig River in May 1997

during high tide in Manila Bay. This backflow was cut short due to the relatively early onset of heavy rains. The maximum chloride ion concentration in the lake water was lower than that in 1995. A significantly close relationship (P< 0.05) between chloride ion concentration (which indicated saltwater intrusion) and the clearing of the lake water was observed as in 1995. However, no algal bloom and related fish kills were observed in 1997. Phytoplankton and zooplankton biomass and composition were observed.

Monthly monitoring of the lake water ended in September 1997 in favor of more intensive sampling in times of rapid changes in the lake such as during saltwater intrusion, algal blooms and fish kills, and after the first heavy rains or typhoon.

A laboratory experiment demonstrated that salt water hastens sedimentation of suspended particles resulting in the clearing of the lake water. A direct relation between increasing levels of chloride ion concentration and settling rate and an inverse relation with turbidity have been observed. Resuspended sediments settled faster in treatments with saltwater than in the control.

Growth Kinetics of Dominant Algal Species

Laboratory cultures of three algal species (Microcystis aeruginosa, Pediastrum duplex, and Cryclotella menighiniana) isolated from the lake water were established. Axenic culture of Microcystis aeruginosa was obtained by treatment with a mixture of different antibiotics (oxytetracycline, streptomycin and chloramphenicol) at 10 m/l. Prior to the algal kinetics experiments. Microcystis cultures were incubated in nitrogen-free medium for nitrogen starvation. Preconditioned cells were then introduced into Microcystis medium with nitrate as the sole source of nitrogen at different concentrations (0.01, 0.1, 0.5, 1.0, 5.0,

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AQD staff sampling water in Laguna de Bay.

10. 20 and 50 mg/1). The experiment is in progress. The other two algal species are being processed to obtain axenic cultures.

To establish optimum conditions for growth, which will be used for the kinetics study, the effects of three light intensities (500, 1,000 and 3,200 lx) on Microcystis and Pediastrum were determined. For Microcystis, growth was highest at 1,000 lx with a specific growth rate (u) of 0 .40/ day. Pediastrum gave a maximum growth of 2.6 x 106 cells at the highest intensity, but higher light intensities are being tested.

Species and Proximate Composition of Laguna de Bay Phytoplankton Culture

in Three Different N:P ratios and Utilization by Nile Tilapia

Laboratory experiments using different nitrogen-phosphorus ratios (2N:1P, 6N:1P and 12N:1P) in the culture of natural phytoplankton in the lake water showed the dominance of green algae in all the treatments followed by the diatoms and blue-green algae. Although some studies showed that low nitrogen-phosphorus ratios tend to favor limitation by nitrogen thereby triggering blooms of N-fixing blue

green algae, this trend was not shown in the present study.

Proximate composition of algae from the different treatments did not differ significantly, except for crude protein as percentage of organic matter which was significantly higher in phytoplankton cultured in the two high N:P ratios. Feeding experiments showed significant growth in Nile tilapia given phytoplankton from the 6N:1P and 12N:1P ratios compared to the 2N:1P ratio.

Digestibility and Metabolizability of Two Commercial Feeds for Tilapia Culture

Experiments were conducted to determine the effect of commercial feeds on fish growth and the environment. In aquaria, the mean body weight, feed conversion ratio (FCR) and protein efficiency ratio (PER) as well as energy and nutrient retention (%) of young Nile tilapia given Feed 1 at 3 feeding rates (5, .5 and 10% daily) did not differ significantly (P> 0.05) after 8 weeks. With Feed 2 given at 5, 7 and 9%, the tilapia had similar growth but PER and energy and nutrient retention were significantly high in fish fed the lowest feeding rate. Results show

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that the 5% feeding rate was sufficient for the fish. Analysis of the external marker in the commercial feeds and in the feces of tilapia in order to estimate apparent digestibility is in progress.

With the use of respirometer chambers, growth and oxygen consumption of Nile tilapia were determined. In experiment 1, fish were given Feed 1 and Feed 2 at 2.5 and 5% daily feeding rate and a control diet (fish-meal based) at 2.5%. Fish on Feed 1 consistently grew faster than fish on Feed 2 at each feeding rate. As the feeding rate increased, growth of Nile tilapia also increased. At the lower feeding rate (2.5%), fish fed the control diet had significantly higher growth than fish given either Feed 1 or Feed 2. The control fish had the best FCR and PER, and the highest energy and protein retention. In Experiment II, the same feeds were tested in the same set up, but the fish were fed to satiation in 3 out of the 6 feedings per day. After 6 weeks, the control fish had the highest body weight, the best FCR, and highest PER.

Back calculated as % of the body weight, daily feeding rate decreased from about 5-6% to about 2 -3% as the fish size increased from 30 g to above 100 g. Feeding rate was lowest in fish fed the control diet, indicating that the amount of feed to be given to fish could be lesser if feed quality is higher. This has an important implication when considering both fish growth and the effect of feed on the environment.

For both experiments, analysis of oxygen consumption is ongoing. Hence, digestibility based on respirometry and metabolizability of the feeds have yet to be determined. N and P released by fish to the water will also be estimated based on carcass and feed analysis.

Analysis of Food Webs - Cultured and Wild Fishes

Samples of tilapia and bighead carp in cages were obtained hourly or every 2 hours over 24-hour periods in order to quantify the uptake of food and determine

Growth and oxygen consumption of tilapia are being studied.

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the major components of the diets of these fish. The quantitative analysis of the gut contents showed that tilapia feed mainly during daytime with only insignificant amounts of food being ingested throughout the night. In carp, this distinction was not so clear, although the anterior part of the gut (carp lacking a true stomach) was fuller during the day than the night. This suggests that either the carp continue feeding throughout the night, albeit at a reduced rate, or that their gut evacuation rate is comparatively slow. Qualitatively, the principal component in the diet of both species was found to be detritus, which made up well in excess of 50% of the gut contents of most fish samples. In view of the turbid water conditions in 1996, this is not surprising since under such conditions, primary productivity was at a minimum.

In 1997, milkfish samples showed that the fish commence feeding before dawn and continue until after dusk, and sometimes extending until midnight. There seemed to be little pattern in the feeding times between different months, although the daily ration tended to decrease as the year progressed. Overall, the majority of the gut content of fish samples in all months had a mixture of diatoms and detritus. Only traces of other algae were found at most times.

Data on food consumption of the culture fish have been analyzed using the MAXIMS program in order to estimate their ingestion and gut evacuation rates.

In another experiment, growth of tilapia and carp in cages without supplemental feeding was observed for about 225 days. Concurrently, Secchi disc readings were determined and water samples were collected in the vicinity of the fish cages for analysis of plankton, chlorophyll a, and estimation of the ash and ash-free components of the total suspended solids in order to explain the growth of the fish.

For wild fishes, samples were collected at two sites, one immediately next to a fishpen, the other in the open water. This was done to compare the effect of fishpens on the distribution and feeding behavior of the wild species. After several samplings, a large-meshed pushnet proved to be the most suitable gear for the capture of sufficient fish of as many different species as possible over a relatively short distance.

The most important fish species caught in terms of number and biomass was the silver perch (Therapon plumbeus), a native species commercially fished and principally used as feed for ducks or pigs. Despite its small size, this species makes up more than 50% of the biomass of wild fish in Laguna de Bay. The second most commonly captured species is the native Manila catfish (Arius manilensis) followed by the introduced Nile tilapia. Shrimps of various species and the commercially unimportant ornate sleeper (Ophiocara aporos) also form an important part of the catch. White goby (Glossogobius gurus) were also caught in some months. In general, the catch close to the fishpen outweighs that from the open water, suggesting that aquacultural structures have some beneficial effect on the wild fish populations. Qualitatively, silver perch and ornate sleeper feed mainly on molluscs and, to a lesser extent, crustaceans. Manila catfish also feed on these, but crustaceans form the greater part of their diet. Tilapia feed almost exclusively on plankton and detritus. The quantitative uptake of food by the various species is being analyzed.

A Modeling of Eutrophication in Laguna de Bay as a Tool for Rational

Resource Management

A lake model originally developed for Shin-Nippon Meteorological and Oceanographical Consultants Co., Ltd. (METOCEAN) was modified and used to simulate the water quality of Laguna de

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Bay. The METOCEAN model made use of the 1984 meteorological and water quality data collected from different government agencies. Hydraulic modeling was applied to obtain basic circulation patterns upon which the water quality modeling was based.

Results of the hydraulic modeling suggest that steady backflow of saltwater from Pasig River reaches deep inside the bottom layer of the lake although the lake water flows out through the Pasig River. Thus, the water quality model for Laguna de Bay focused on the unique role of the saltwater intrusions in limiting phytoplankton productivity. The result of saltwater intrusion was simplified as the change of depth of euphotic zone in the

Ecological study on Laguna de Bay in collaboration with foreign institutions continues.

lake water estimated from the Secchi disc readings. For simplicity and expandability of the model as a predicting tool. Secchi disc transparency was the only forcing function considered in the study.

Initial results of the water quality model differentiated conditions with and without saltwater intrusion. Without saltwater backflow, higher concentrations of total inorganic nitrogen and inorganic phosphorus and low dissolved oxygen especially in the bottom layer are predicted. Under this condition, release of large amounts of nutrients in the sediments is expected to be the dominant source of total inorganic nitrogen in the lake.

The study is the first attempt to model the lake. The model still needs calibration and validation with measured values of recent years before adopting its usefulness as a tool for predicting water quality of Laguna de Bay.

GENETIC CHARACTERIZATION OF HATCHERY-BRED, FARMED

FINFISHES, SHELLFISH AND ENDANGERED FINFISHES

AND SHELLFISH

The project aims to investigate genetic variation in cultured and natural populations of milkfish and hatchery populations of tilapia. It also looks into the correlation bet-ween gene-genotype dis-equilibrium and broodstock management in cultured populations and studies the genetic structure of two Philippine local fishes, "tawilis" and "sinarapan," in collaboration with other institutions.

Aquaculture activities, under certain circumstances, are known to impose untoward genetic effects either on wild populations or aquaculture stocks. Also, the loss of heterozygosity in hatchery stocks is well documented. Along this line, a study was conducted on genetic characterization of different generations of Nile tilapia.

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Nine enzymes and skeletal muscle protein were analyzed by starch gel electrophoresis in three generations of the tilapia strain from Thailand (NIFI) and two generations of selected Nile tilapia. Preliminary results showed that polymorphism or genetic variation is indicated in the sarcoplasmic protein and in six out of nine enzymes analyzed while monimorphism was revealed in three enzymes. A large number of parental fish (no less than 100 pairs) have been used in mass spawning of these three generations of Nile tilapia and two generations of selected Nile tilapia. This may be the reason for the presence of a high degree of genetic variation in the six enzymes and sarcoplasmic protein analyzed. More enzymes are going to be analyzed in 1998.

GENETIC DIVERSITY IN AQUACULTURE: A PROGRAM FOR

ECONOMICALLY AND SOCIALLY SUSTAINABLE CONSERVATION

AND DEVELOPMENT

The objectives of this completed collaborative project with Dalhousie University and St. Mary's University of Canada were: to investigate the existence of local strains of culture fish, their nature and their genetic, socio-cultural and economic value; to develop interdisciplinary tools for aquaculture decision making regarding the balance between genetic improvement and genetic conservation, and to explore the potential for, and the genetic and socio-economic sustainability of on-farm genetic conservation.

This project is the first to consider interdisciplinary methodology for the evaluation of various types of genetic improvement technology on overall farm productivity, on biodiversity and on the social, cultural, financial and economic aspects of human society. Using rapid rural appraisal-based analyses and DNA fingerprinting, studies revealed a geographic and socio-economic

structuring of genetic biodiversity and genetic quality of broodstock in Indonesia, China, Thailand, and Malawi. Results also showed that the "hatchery/mobile trader system" (which is developing as an indigenous solution to the adverse socioe-conomic consequences of declining natural fish stocks) affects the genetic quality and biodiversity of the silver barb in northeast Thailand.

LARVAL FOOD PROJECT

This project was started in 1997 with 3 studies being undertaken. It aims to develop better techniques in mass production of plankton as natural food for larval fishes, crustaceans and mollusks raised in hatcheries.

Initial activities focused on acquisition and isolation of selected microalgae. As of the reporting period, two species of Navicula sp. and one species of Chaetoceros sp. were isolated. Skeletonema tropicum stock culture was already purified. Isolation of Nitzchia sp. is also ongoing. The copepod Acartia and Oithonia were also isolated and mass produced.

Meanwhile, initial results of the study on the rotifer Acartia tsuensis showed that highest egg production was observed in copepods fed with a combination of Skeletonema and Tetraselmis. Further observation and analysis are ongoing.

MANGROVE AQUASILVICULTURE PROJECT

This project aims to develop or verify technologies that are compatible with mangroves, undertake economic analysis of the technologies, and incorporate the technologies in the overall mangrove conservation and rehabilitation program.

In an effort to contribute to mangrove conservation efforts, one study dealt on developing techniques to counter the ill

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The mangrove aquasilviculture project seeks to develop technologies as a contribution to the mangrove conservation and rehabilitation program.

effects of shrimp pond effluent emptying into adjacent mangrove ponds. It was found that flooding and subsequent

immersion of mangrove roots resulted in deaths of the mangrove Soneratia but not Avicennia.

The mangrove species Rhizophora was then planted in the pond and is now growing well, as the effluent flood could not affect its high roots. Preliminary data show that water quality in both the shrimp and mangrove ponds exhibit high salinity. The mangrove pond was also found to have a lower pH (more acidic) than the shrimp pond. There was a lower dissolved oxygen level in the mangrove pond because of decaying leaves in the pond. The shrimps grew slowly, which may be due to the high salinity levels in the shrimp pond.

In another study, the bivalve found in mangrove areas and locally called "imbao" in the Philippines, was identified as Anodontia edentula Linne. Some of its characteristics have been identified. Males and females can be distinguished when

The bivalve, locally known as "imbao" has been identified as Anodontia edentula.

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their shells are 3 mm long, and their gut can be seen when they are 5 mm long. The clams are found 48 cm below the mud with juveniles concentrated in the upper 25 cm. In the more muddy areas, the bivalve can be found 1 meter much deeper inside the mud.

SOCIOECONOMICS RESEARCH

COMMUNITY FISHERY RESOURCES MANAGEMENT

Started in 1991, the community fishery resources management (CFRM) project is a development-oriented research designed to help sustain and enhance the livelihood of people in the coastal areas. It aims to learn from the collaboration of community organizations, biologists, and social scientists in developing and adopting aquaculture technology and inshore fishery resource management techniques in a selected community in the Visayas (Malalison5 Island, Antique). Data generated from this project will be used to assess the replicability of the project's experience in other project sites in the Southeast Asian region.

The project has two sub-projects: one studies the fishery resources and development of appropriate technology and the other looks at the socio-economic aspects of the project.

The project's Phase I (1991-1993) involved community organizing efforts in Malalison Island, institution building and the introduction of seaweed farming as alternative livelihood for the island residents. Studies were made on the marine resources of the island, the traditional boundaries and territorial use rights, the economic utilization of resources, and cultivation techniques for seaweed.

Phase II started in 1994 with the implementation of the territorial use rights in fisheries and test deployment of prototype concrete artificial reefs. It also included economic, environmental and social impact assessment , institutional arrangements in fishery co-management, ethnographic studies, economics of seafarming techniques, and management of fishery cooperatives.

Impact Analysis of the Community Fishery Resource Management Project

in Malalison Island

This sub-project aims to evaluate the environmental and socio-economic impact of the project in the project site using measurable indicators.

In 1996, the CFRM project continued its resource assessment studies of selected marine communities in Malalison Island. The study showed that the coral community in the fringing reefs of Malalison Island is composed of 120 species of hard corals from about 50 genera. Mean cover of live hard coral (40%) is comparable with the state of many reefs in the Philippines.

Reef fishes were determined to be some 219-238 species from 30-34 families with damselfishes predominating. Fusiliers and surgeonfishes dominate the standing biomass of the community.

The three module-type concrete artificial reefs earlier deployed in 1995 in Gui-ob and Buganti reefs in the island have attracted fish to seek shelter and food in the reefs. Large surgeonfishes exploited by island fishermen aggregated abundantly in the Gui-ob artificial reef. Other reef organisms such as algae, sponges, hard corals, etc. have been observed.

The fishery practices in the island were also assessed. It was found that the catch per unit effort (kilos per fisher per hour) was highest for speargun with 5 Also spelled and pronounced as Mararison.

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Community resource assessment studies of selected marine communities in Malalison continue to be undertaken. (Photo by C.L. Marte)

compressor followed by drift gill net. drive-in gill net. set gill net. spear gun. hook and line. Each of these fishing equipment were designed to catch specific fish. The dominant species caught with these fishing gear were cuttlefish, squid and octopus, fusiliers, groupers, rock cod. needlefishes, half-beaked garfishes, flying fishes, herring, sardines and scads. Total fish yield was estimated at 9.73 tons per square kilometer per year.

A study is looking into the prospects of stock enhancement and searanching in the island. This study indicated there were no live top shell nor abalone in the islands sea grass, in rocky inter- and sub-tidal areas and reef flat. The study then introduced Tectus sp. shell in three sites. After two days, many of the shells (47-90%) were seen. However, quite a few shells were recovered (9-16%) after a month. No shells were recovered after six months. The study continued with transplanting the seaweed Sargassum sp. in two sites with little or no vegetation. The test transplantation failed but an improved method of attaching planting materials on concrete blocks was devised to solve the problem.

A technique to help divers in reliably estimating the length of fishes underwater

has been developed. The dive trials using bamboo sticks of different lengths and a reference scale demonstrated that such dive exercises can improve the diver's skill in obtaining reliable estimates of lengths of objects such as fish underwater. The project aims to teach this estimation technique to the island's divers.

Socio-Economic Indicators in Evaluating the CFRM Project

in Malalison island

The socio-economic aspects of the CFRM project were also studied. An analysis of the project activities and institutional arrangements of co-management of fisheries resources in Malalison Island was made.

Project participants conducted several meetings, consultations, and informal discussions that resulted in new organized groups and organizational interactions relating to project activities.

Presently, the island-based organizations participating in the project are the Fishermen's Association of Malalison Island (FAMI). Barangay Fisheries and Aquatic Resource Management Council (BFARMC), and the Barangay Council. On the other hand.

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Dr. Clarissa Marte. AQD Research Division Head, discusses marine reserve concepts with cooperators at Malalison Island. Antique.

those based in the municipality are the Culasi Sangguniang Bayan and the Municipal Fisheries and Aquatic Resources Management Council (MFARMC).

The most important achievement of Mararison was the formulation and eventual approval of an ordinance declaring the island's Gui-ob reef as a fish sanctuary. Representatives of community-based institutions (FAMI, FARMC, and the Barangay Council) are presently undertaking activities for the full implementation of the fish sanctuary, i.e. putting up markers in the site, repairing of pumpboat for monitoring fishing activities in the island, and conducting an information drive among the community residents.

The project also conducted a case study of the institutional arrangements in the fisheries co-management in the island. Results indicated that respondents with higher education significantly perceived the positive impact of the project. In addition, the higher the respondent's perception of an improved state of fishery conditions in the island,

the higher was the perception of the project's positive impact.

The study confirmed the success of the CFRM project in Malalison Island as respondents noted the significant and positive changes on the coastal ecosystem of the island. Improvements on the socio-economic conditions of the fishing community were also evident after the six-year project implementation.

However, the fisherfolks' satisfaction with their occupation and their total dependence on fishing for food had a low relationship with the total perceived impact of the project. This could be attributed to the fact that the fishermen are used to freedom in the exploitation of the sea, and that the open access nature of fishery resources reinforces this freedom. The exclusivity of access rights may have been perceived by the respondents as curtailing their freedom for they have been accustomed to fishing anywhere without intervention from government institutions. This could reduce their income especially if their subsistence is solely derived from fishing. This could also mean that the fishermen

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are still not satisfied with the present co-management arrangements and may want some improvements on them.

Apart from the above-mentioned studies in Malalison Island, another study is examining how people's access to and control of small-scale fishery resources have changed over time. This is being conducted in the Palawan province of the Philippines. A combination of qualitative and quantitative research techniques (e.g., free lists, pile sorts, key informant interviews, life histories, focused group discussions, mapping exercises, etc.) is being used.

The study will gather data on 1) content of knowledge about fishery resources and how these differ in terms of age and gender, 2) the major resource practices, how these differ in terms of age, gender, and class, and how these have changed over time, 3) how access to resources is determined, who control access, and how has this changed over time, and 4) how perceptions regarding changes in resource availability are influenced by changes in systems of control and access. Presently, key informant interviews with long-time residents of a village in the research site are ongoing. •

41

TECHNOLOGY VERIFICATION

AQD-generated technologies got a boost with the launching in June 1996 of an applied

research program through the technology verification and technology transfer project (TVP). The project aims to test aquaculture technologies and existing practices as to their economic and commercial viability.

The project went into real-life situations, using aquaculture farms and collaborating with fishfarmers and other institutions to validate selected technologies. In effect, AQD reinvigorated its efforts to bring technology to the end-users' doorsteps. It is thought that the TVP experience could ignite a more widespread interest in aquaculture technologies, and thus hasten adoption of these technologies. This way. AQD hopes

Crab culture in existing mangroves. Initial results of TVP studies are encouraging.

Grouper culture as an alternative to shrimp production is a viable option.

to contribute to the regions deep concern for food security.

In 1996-1997, AQD implemented 9 projects in 23 sites situated mostly in the Visayas region, Philippines. Twenty-four (24) collaborating private farms and government institutions assisted in the implementation of the studies (Table 9).

Four TVP projects, the study on grouper culture, hatchery-bred milkfish, and mud crab culture in tidal flats with existing mangroves and in brackishwater ponds were completed.

In the grouper project, results show that after 7 months of culture, a total harvest of 1,512 kilos was obtained from the 0.9-ha pond of the cooperator, Sanson Farm. The survival rate of grouper was recorded at 80%. The average weight of the fish was about 1.5 kg. Initial calculations showed that a gross revenue of US$11,140 and a net profit of US$4,177 were achieved. In the meantime. 30.000 grouper juveniles have been stocked in 12 selected half-hectare pond compartments for commercial production by the cooperator.

In the mud crab project, cost-return and partial budgeting analysis showed that on a per crop basis, a 1,200 sq m-pen with existing mangroves stocked with mud crab using a prescribed stocking density and feed types was economically viable. The return on capital investment was 72-86%. This 1,200-sq m area is recommended so that each family in a fishing village could have a share of the resources.

The technology verification project on the nursery and grow-out of milkfish derived from hatchery seeds was conducted at Gatuslao and Jalandoni farms in E.B. Magalona, Negros Occidental Province, Naranjo Farm in Carles, Iloilo province and Arches Farm in Capiz. The study showed significant results.

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TECHNOLOGY VERIFICATION AQD 1996-1997 REPORT

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Hanging raft method for oyster and mussel production is a continuing TVP study in Capiz and Aklan.

TTable 8 . A Q D t e c h n o l o g y v e r i f i c a t i on pro jec ts and pro jec t s i t es .

Title of Study

Grouper culture in brackishwater ponds

Nursery and grow-out culture of milkfish derived from hatchery seed

Cage culture of tilapia in small water impoundment 's

Environment-friendly schemes for disease prevention in prawn farms

Broodstock management of economically important and cultured finfishes Honda Bay Foundation

Culture of mud crab in brackish-water ponds

Biculture of seaweed and milkfish in brackishwater ponds

Mud crab culture in tidal flats with existing mangroves Manalo Multi -purpose Coop

Hanging raft method of oyster and mussel production

Cooperator

Sanson Farm

Jalandoni Farm Gatuslao Farm Naranjo Farm Arches Farm Capiz Institute of Technology lloilo State College of Fisheries (ISCOF) Department of Agriculture

Bingawan Mult i -purpose Cooperative Local Government of Bingawan

Santa Clara Farm Golden Prawn Farm Sanson Farm

Inland Fisheries and Searanching Station, Department of Agriculture Region IV

Senorita Island, Honda Bay, Palawan

Jalandoni Farm, Montel ibano Farm

Gargarita Farm

Iloilo State College of Fisheries (ISCOF)

KASAMA cooperative Local Government , Kalibo Puerto Princesa City, Palawan

Bureau of Fisheries and Aquatic Resources (BFAR)

Local Government , Local Government, President Roxas Local Government , Batan Local Government, New Washington

Project Site

Sum-ag , Bacolod City

E.B. Magalona, Negros Occidental Himamaylan, Negros Occidental Carles, Iloilo Roxas City Roxas City Barotac Nuevo, Iloilo

Iloilo City

Bingawan, lloilo

Talisay, Negros Occidental E.B. Magalona, Negros Occidental Sum-ag , Bacolod City

Tiniguiban Cove, Puerto Princesa City, Palawan

E.B. Magalona, Negros Occidental

Himamaylan, Negros Occidental

Barotac Nuevo, Iloilo

Kalibo, Aklan

Ivisan, Capiz

Ivisan, Capiz President Roxas, Capiz Batan, Aklan New Washington, Aklan

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TECHNOLOGY VERIFICATION AQD 1996-1997 REPORT

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Tilapia cage culture in small water impoundments is another TVP study being verified.

During the nursery phase of 60 days culture, fish stocked at 10 fishes per square meter in a 0.5-ha pond showed a 68 % survival rate. Very few were deformed (0.23%) and the relative growth increment was 0.17g/day/ f ish. Average body weight at harvest was 10.2 lg.

In the grow-out phase, milkfish were reared under a semi-intensive scheme. The stocking rate was 1 fish per sq.m. in 4 ponds with areas ranging between 0.6 to 0.8 ha. The average weight of the fish at stocking was 70g. Sixty days after, the fish was harvested. At harvest, the average survival rate was 93.75 %. Deformity was almost nil (0.05%). Relative growth increment was 3.71 g / f i sh /day . The body weight of fish averaged 290.97g. The average yield on a per-hectare basis was calculated at 2.98 tons.

In the grow-out phase following the progression system using two contiguous ponds (0.6 and 2.4 ha) stocked with 12.000 hatchery-bred milkfish fingerlings fed with natural food alone, results showed a very high survival rate (99%). an almost nil deformity (0.003 % ) . 1.66 g / f ish/day relative growth increment and an average body weight of 204 g. Total biomass after 105 days of culture was about 2.4 tons. With this method of culture, three stocking schedules can be done within a year. Production therefore, using this method would give an annual yield of 2.4 tons per hectare per year. This yield is comparable with, if not better than the milkfish culture scheme using wild fingerlings.

A series of verification runs on the culture of mud crab in brackishwater ponds using nylon net enclosures was

conducted in three sites: Jalandoni and Montelibano Farms in E.B. Magalona and Gargarita farm in Himamaylan, all in Negros Occidental province. Stocking density used was 1 crab /m 2 in 0.5-hectare ponds in each site. Findings showed an average production of 744.7 kg (or 1.489.4 kg per hectare) after a series of selective harvests during an average 130 culture days. The survival rate ranged between 63 to 72% and average body weight at harvest ranged from 285 to 389 g. Average total feed consumed using chopped trash fish was 3.297.3 kg with a feed conversion ratio of 4.52. Based on initial average body weight of 13.7 g, the mean relative growth increment was 2 .37g /day /crab. Further replications are planned to be conducted in other parts of the country.

The project experiences have been documented and written. Extension-type manuals on grouper and mud crab culture are now being prepared for mass distribution by 1998. It is expected that extension workers, teachers, aquaculturists. businessmen and others will be benefited with this publication.

Meanwhile, the rest of the technology verification projects are ongoing. In support of viable grow-out culture technologies, verification studies on broodstock management and seed production of cultured finfishes are being done. These are aimed at meeting the anticipated increase in demand for their seeds or fry in the near future. With respect to shrimp, environment-friendly and alternative production schemes are being tested to minimize occurrence of diseases in shrimp ponds. •

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TRAINING ACTIVITIES

AQD continued to train aquaculture specialists, technicians, researchers,

extensionists and educationists, farmers, and aquaculturists as part of its mandate to help develop the manpower for the aquaculture industry. It offered 14 training courses - 7 regular and 7 special training courses. During the reporting period, a total of 327 participants from SEAFDEC member countries and from 23 other countries attended the training courses.

Of the total number of 327 participants in all the AQD training courses, almost half 152 out of 327) came from the Philippines (Table 10). This was followed by 54 participants from Vietnam, 28 from Thailand, and 26 from Malaysia. Sixty (60) participants from 23 Asian and South Pacific countries also attended AQD's training courses.

A total of 186 participants attended the regular training courses while the special courses were held for 141 participants.

TTable 9. Regu lar t ra in ing courses c o n d u c t e d and number o f par t i c ipants .

Course Title Number of Participants

Regular Courses Aquaculture Management Fish Health Management Marine Fish Hatchery Freshwater Aquaculture Shrimp Hatchery Operations Fish Nutrition Culture of Natural Food Organisms

Sub-total

Special Training Courses Coastal Aquaculture and

Resource Management Milkfish Farming Shrimp Culture Seaweed Farming Brackishwater Aquaculture Aquaculture Technology Sustainable Aquaculture and Coastal Resource Management

Sub-total Total

37 27 33 29 15 32 13

186

65 9 1 1

32 14

14

141 327

Table 10. Distribution of training participants by country of origin.

Country Number

SEAFDEC member countries Philippines Vietnam Thailand Malaysia Brunei Darussalam Singapore

Other countries Cambodia Indonesia Sri Lanka China Iran Myanmar India Bangladesh Fiji Tuvalu Australia Jordan Kenya Kiribati Micronesia Nepal Pakistan Palau Papua New Guinea Saudi Arabia South Africa Tanzania Western Samoa

Sub-total

Sub-total Total

152 54 28 26 6 1

267

8 8 5 5 3 4 4 5 3 2

1 1 1 1 1 1 1 1 1 1 1 1 1

6 0 3 2 7

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TRAINING ACTIVITIES AQD 1996-1997 REPORT

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Training courses at AQD provide participants with hands-on experience in addition to classroom activities.

Special Training Courses

Aside from the regular training courses, AQD also offered and conducted special courses. These are the following:

11) Third-Country Training Program on Coastal Aquaculture and Resources Management

First conducted in 1995. this two-month course is a five-year collaborative effort of AQD and the Japan International Cooperation Agency (JICA). The course aims to provide the participants from Asian countries with the opportunity to upgrade their knowledge and skills on coastal aquaculture and resource management. This is part of AQD's effort to promote "south-south" cooperation.

In 1996. this course was attended by 14 participants from Bangladesh, Cambodia, China. India. Indonesia. Malaysia, Myanmar, the Philippines, Sri Lanka, Thailand and Vietnam.

For the 1997 session, the course coverage was expanded to include more topics in resource management anchored on sustainable development. It was likewise attended by 14 participants from Asian countries.

Subsequently, a two-week version of the course was held on-site in Vietnam in cooperation with Can Tho University in Can Tho City. The course was designed to introduce local government officials to the concept, methods and practices of coastal resource management (CRM) and

AQD held for the first time outside the Philippines its training course on Coastal Aquaculture and Re Management. This was conducted in Vietnam in collaboration with Can Tho University of Vietnam.

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acquaint them with participatory and gender-sensitive approaches. It also aimed to encourage participants to be able to situate aquaculture activities in their respective areas within the context and concerns of CRM and biodiversity conservation and management. Twenty-two (22) Vietnamese participants coming from academic, research and other government institutions in the whole country attended the course.

This collaborative training program will end in 1998. Negotiations are being made for the extension of the program beyond 1998 in order to cover more countries in Asia as well as in Africa.

22) Milkfish Farming

Two batches of this course were conducted in 1997 (07 May-16 June; 21 November-21 December) for 9 participants from 6 South Pacific countries (Fiji, Papua New Guinea, Western Samoa, Palau, Kiribati and Tuvalu). The first batch of the course was sponsored by the United Nations Development Programme's Food and Agriculture Organization (UNDP/FAO) while the second batch was financed by the Fiji Fisheries Division. The course covered major aspects of milkfish spawning, larval rearing, wild fry collection and fabrication of fishing gears, construction of cages, pond design and construction, and different culture practices.

3) Shrimp Culture

A one-month training course on shrimp culture was conducted for one participant sponsored by a private sector based in Saudi Arabia. The course was held 14 July to 12 August 1997.

4) Seaweed Farming

A two week-intensive training course on seaweed farming was conducted from 3-14 November 1997 for one Kenyan participant sponsored by the IOC-

UNESCO. The course focused on the culture, management and Postharvest of seaweed including extraction of agar and carrageenan.

5) Brackishwater Aquaculture

This course was conducted at Brooke's Point, Palawan, Philippines from 28-31 January 1997 for 32 participants. The training course was sponsored by the Philippine Department of Science and Technology, the local government units, and the Society of Aquaculture Engineers of the Philippines.

6) Aquaculture Technology

The course was conducted from 3-7 February 1997 with fourteen (14) participants from the Regional Agriculture and Fishery Council (RAFC)-Region IV attending. The course was under the auspices of the Agriculture and Fishery Council of the Philippines-Department of Agriculture. The objectives of the course were: (1) to orient the participants with the different aspects of aquaculture; (2) to promote interaction between government and non-government (NGO) administrators and the A Q D researchers; and (3) to acquaint the participants with the activities of AQD.

7) Coastal Aquaculture and Resource Management

Conducted on 3-14 November 1997, the two-week course was held as a response to the request of the Philippines' Department of Agriculture-Agricultural Training Institute (DA-ATI) based in Carmen, Cebu.

The course was attended by fifteen (15) participants from the different training centers of DA-ATI all over the Philippines. The course was designed to upgrade the knowledge and skills of the participants on coastal aquaculture and resource management.

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88) Sustainable Aquaculture and Coastal Resource Management

Conducted from 16 November to 6 December 1997, the three-week course had nineteen participants who were schoolteachers from several fishery schools in Region VIII of the Philippines. The training course was in response to the request of the Technical Education and Skills Development Authority-Region VIII, Tacloban City. The course was designed to upgrade the knowledge and skills of the fishery schools' teachers on sustainable and coastal resource management.

• Aklan National College of Fisheries, Kalibo, Aklan

• Iligan Institute of Technology, Iligan City

• St. Paul College, Iloilo City • Mindanao State University, Marawi

City • West Visayas College of Science and

Technology, Iloilo City • ABBA School of Electronics, Iloilo City • STI, Iloilo City •

Practicum and Internship Programs

AQD also continued to provide opportunities for one-month practicum and internship programs for graduating students and new graduates of B.S. Fisheries and Marine Biology. Program activities include various aspects of fisheries technology as these relate to the students' major field of interest.

In 1996 and 1997, a total of 119 students served their practicum and internship programs at AQD. These students came from the following schools:

• Tario-Lim Memorial Antique School of Fisheries, Tibiao, Antique

• University of the Philippines in the Visayas, Miag-ao, Iloilo

• Camarines Sur Institute of Fisheries and Marine Sciences, Camarines Sur

• Iloilo State College of Fisheries, Barotac Nuevo, Iloilo

• System Institute of Technology, Makati City

• System Institute of Technology, Iloilo . City

• Negros Occidental School of Fisheries, Bacolod City

• Mindanao State University, Naawan, Misamis Oriental

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INFORMATION DISSEMINATION

AQD stepped up its information activities in line with the Department's thrust of

reaching more of its target beneficiaries.

A major development was the launching of the AQD web page in the Internet on 09 July 1997. The web site is www\\seafdec.org.ph. The AQD web page has attracted more than 500 website visitors.

The AQD library served more readers compared to previous years. It has increased its holdings by more than 1.000 volumes of serials and books.

More than 15.000 visitors were briefed on AQD R&D programs, and viewed the exhibits at the AQD Museum and Biodiversity Garden.

Extension Publications

Prior to 1997, AQD published two newsletters: the quarterly SEAFDEC Asian Aquaculture (SAA) and the bimonthly Aqua Farm News (AFN).

SAA reported on all phases of aquaculture and was intended for researchers and policymakers. AFN served as production guide for fishfarmers and extension workers. In 1996, four issues of both SAA and AFN were printed and distributed.

In 1977, SAA and AFN were merged into a new SAA, published every two months. The new SAA reports on various topics on sustainable aquaculture. It targets fish-farmers, aquaculturists, extensionists, policy-makers, researchers, and the general public as its audience. The subsequent SAA issues featured topics on culture of abalone, mud crab, and sea bass and on integrated farming.

AQD likewise produced the following publications:

The AQD web page.

11) Life history of milkfish, Chanos chanos Forsskal, 1997.

This is a fully illustrated color poster produced by the AQD Museum and Biodiversity Garden. Some 50 copies have been distributed to fishfarmers, and to representatives of academic, research and extension institutions.

2) Proceedings of the seminar-workshop on breeding and seed production of cultured finfishes in the Philippines, 1997. Marte, C.L. , G.F. Quinitio and A.C. Emata, eds. Iloilo, Philippines. 182 p.

This documents the proceedings and 13 papers on breeding and seed production presented in a seminar-workshop of the same title hosted by AQD on 4-5 May 1993 in Tigbauan, Iloilo.

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INFORMATION DISSEMINATION AQD 1996-1997 REPORT

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AQD visitors Dignitaries continued to visit the AQD Tigbauan Main station. Notable among them were Philippine Senator Leticia Shahani (left): the Japanese Ambassador to the Philippines, His Excellency Hiroyaki Yushita who was accompanied by his wife (middle photo): and SEAFDEC Secretary General Mr. Udom Bhatiyasevi (bottom photo).

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Publications output AQD's major publications include the quarterly SEAFDEC Asian Aquaculture (top photo), the poster on the life history of the milkfish (middle photo) and other various reports and books of proceedings of scientific meetings and conferences (bottom).

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33) Feeds for small-scale aquaculture. 1996. Santiago, C.B., R.M. Coloso, O.M. Millamena, and I.G. Borlongan, eds. Iloilo, Philippines. 144 p.

This documents the proceedings of the first national seminar-workshop of the same title hosted by A Q D on 1-2 June 1994 in Tigbauan, Iloilo. It carries 11 full papers, and 19 abstracts.

4) Simpleng gabay sa pagtitilapya. 1996. R.V. Eguia et al., Iloilo, Ph i l ipp ines . p.

Two extension manuals ("Pagpapalaki ng tilapya" and "Pagpapaanak ng tilapya") written in Filipino and features details of tilapia spawning and culture methods .

5) 1997 Highlights. AQD. Iloilo, Philippines. 14 p.

This publication reports on AQD 's accomplishments in 1997 in the areas of poverty alleviation, food security issues, environment-friendly aquaculture, and research on export and cash crops. Also discussed are the Department 's activities in technology verification, training and information dissemination.

6) 1996 Highlights. AQD. Iloilo, Philippines. 12 p.

Like the 1997 highlights, this discusses very briefly AQD 's accomplish-ments in 1996. It features AQD's invigorated emphasis on technology verification and techno-transfer even as it continued its ongoing R&D programs.

AQD also reprinted the following:

1} Farming of prawns by JH Primavera et al.

2) Diseases of penaeid shrimps in the Philippines by MCL Baticados et al.

3) Broodstock of sugpo, Penaeus monodon by JH Primavera et al.

4) Important fish and shrimp fry in Philippine coastal water:

identification, collection, and handling by TU Bagarinao et al

5) Diseases of shrimps in the Philippines by CL Pitogo et al

6) Prawn hatchery operations by FD Parado-Estepa et al

7) Management of milkfish broodstock by AC Emata et al

8) Feeds and feeding of milkfish, Nile tilapia, Asian sea bass and tiger shrimp by OM Millamena et al.

9) Feeds and feeding for grow-out culture by FP Pascual and RV Rivera

AQD in The Mass Media

In 1996, 26 news articles on AQD's activities were published in Philippine national dailies. This increased to over 70 articles in 1997. The most extensive article was the full-page coverage of AQD's 23rd anniversary.

Due to this AQD exposure in the mass media, much interest was elicited from the public. Information on the community fishery resource management project, the Save-the-Shrimp task force that A Q D spearheads, hatchery-produced milkfish fry, the freshwater lake conference, and AQD's various training courses was much sought. A Q D also participated in 4 fairs and 2 exhibit occasions.

A Q D updated its briefing video for visitors, which includes a look on AQD 's 25-year history. The Department also continued its production of a video on the mangrove resource conservation program.

Other Extension-Type Activities

Aside from fulfilling its research, training and information dissemination functions, A Q D was also engaged in several extension-type activities. These include the following:

1) Oplan "Sagip Sugpo" (Shrimp) Task Force

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The Philippine Government created in September 1996 the Oplan "Sagip Sugpo" (Shrimp) Task Force consisting of specialists from BFAR, PCAMRD, AQD, University of the Philippines in the Visayas (UPV), Mindanao State University (MSU)-Naawan Campus, Central Luzon State University (CLSU), and the Negros Prawn Producers Marketing Cooperative, Inc. (NPPMCI).

The general objective of the Task Force is to rehabilitate the "sugpo" culture industry and make it sustainable through a focused effort to develop sound shrimp health management techniques. Specially, the Task Force shall set directions for research on shrimp health management and production aspects to be implemented by the different agencies.

In 1997, the Task Force conducted a nationwide rapid assessment of the shrimp industry. Subsequently it started implementing a field verification study of the shrimp culture techniques found to be environmentally friendly and which have been used successfully by commercial growers. Results of the rapid assessments yield an indicative status of the Philippine shrimp industry.

22) Accelerated Transfer of Milkfish Hatchery Technology

The project is likewise a collaborative effort among AQD, BFAR, and the private sector. It involves the accelerated transfer of milkfish hatchery technology to the private sector. The cooperators involved are former operators of shrimp hatcheries in neighboring communities around AQD's Tigbauan Main Station. The project utilizes the excess milkfish egg from broodstock maintained at AQD. As of the reporting period, some 33 million eggs and larvae were provided free to 5 private hatcheries collaborating with A Q D in this technology transfer project.

The project also held a one-day conference on the culture of hatchery-

produced milkfish fry. The activity was made part of the annual D.K. Villaluz Memorial Lecture series conducted during the 24th Anniversary of AQD. The conference was attended by 95 pond owners, hatchery operators, aquaculturists, representatives from the academe and government sectors, and A Q D researchers. Several recommen-dations were made regarding various aspects of hatchery production, extension and dissemination of information, continuing basic research on fry culture, nutrition, and other related matters.

3) Community-based Coastal Resource Management Project

A Q D collaborated with ICLARM, the SEAMEO Regional Center for Graduate Study in Agriculture (SEARCA), and the Tambuyog Development Center, a non-government organization based in Palawan, Philippines in implementing this project. The project is a spin-off of the favorable results of AQDs study on community fishery resource management (CFRM) which is ongoing.

A Q D is tasked to spearhead the dissemination and transfer of technology to Palawan-based institutional partners and fisherfolk organizations in two villages. An initial activity is an aquasilviculture study which aims at demonstrating the feasibility of crab farming in mangrove areas without destroying the mangroves. It is envisioned that when this pilot project proves successful in the Philippines, similar co-management schemes may be done in other SEAFDEC Member Countries.

Scientific Meetings

In 1996, AQD organized and hosted the Second International Conference on the Culture of Penaeid Prawn and Shrimps in Iloilo City. More than 300 participants from 30 countries attended the conference.

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Scientific meetings AQD organized and hosted 3 important scientific conferences. The first was the Second International Conference on the Culture of Penaeid Prawn and Shrimps which was held in Iloilo City in 1996 (left photo).

Also held in the same year in Iloilo City teas the Meeting on the Use of Chemicals in Aquaculture In Asia (AQUACHEM) (middle photo).

Bottom photo shows DENR Secretary Victor Ramos addressing participants during the opening ceremonies of the National Seminar Workshop on Ecological Management of Philippine Lakes in Relation to Fisheries and Aquaculture.

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The conference reviewed the shrimp researches in the past, identified research gaps, and proposed strategies to make the shrimp industry sustainable. Eleven papers presented in the scientific sessions were on biology, ecology and physiology, seed production, nutrition and feed development, diseases, genetics and biotechnology, and socioeconomics. Another 45 papers were presented orally and 30 were poster presentations.

The participants formulated various recommendations for research such as the establishment of breeding programs, formulation of diets to match composition of shrimp diets in the wild, finding alternatives to eyestalk ablation, environmental manipulation and culture techniques, early identification of vibriosis, study on the epidemiology of white spot disease in the region, environmental impact of culture systems and pond design and management.

The conference proceedings will be published in the Netherlands-based Elsevier's Aquaculture Journal.

AQD also hosted the Meeting on the Use of Chemicals in Aquaculture in Asia (AQUACHEM) at its headquarters in Tigbauan, Iloilo. Attended by more than 100 participants and observers from 21 countries, the AQUACHEM Meeting synthesized and updated information on the use of chemicals in aquaculture with emphasis on the various aquaculture systems and species utilized.

Presentations included antibacterial chemotherapy in aquaculture, ecological effects of chemical usage in aquaculture, transferable drug resistance plasmids in fish-pathogenic bacteria, use of chemicals in aquafeeds, effects of use of chemicals in aquaculture, on human health, regulations on the use of chemicals in aquaculture, and use of organic manure, fertilizers and soil and water conditioners in aquaculture. Also presented were 14 country overview papers on the use of "aquachemicals."

Following immediately was the ad hoc meeting of the Working Group on Environmental Impact of Aquaculture of the I M O / F A O / U N E S C O - I O C / W M O / A E A / U N / U N E P Joint Group of Experts on the Scientific Aspects of Marine Environment Protection of GESAMP. Discussed were environmental and human health issues related to the use of chemicals in coastal aquaculture as practiced worldwide. The ad hoc Meeting came up with baseline information out of which a set of guidelines for use of chemotherapeutants and pesticides in coastal aquaculture will be eventually formulated.

In 1997, A Q D organized the "National Workshop on Conservation and Ecological Management of Philippine Lakes in relation to Fisheries and Aquaculture" in cooperation the Bureau of Fisheries and Aquatic Resources and the Philippine Council for Aquatic and Marine Research and Development. The workshop was held 21-23 October at the SEAMEO INNOTECH headquarters in Diliman, Quezon City. The workshop aimed at assessing the present status of the of Philippine lakes with emphasis on their ecology and fishery resources and mapping out future strategies for lake conservation, management and research. Some 100 participants from academe, research and extension and other institutions attended the workshop.

The participants formulated both short- and long-term action plans. These included 1) publication of an updated list of Philippine lakes with basic data in each region, 2) conduct of rapid resource assessment studies on hydraulic retention time, dissolved oxygen, temperature pro-file, biological oxygen demand, 3) publica-tion of the lake workshop proceedings, 4) conduct of enhancement and evaluation studies including the socio-economic aspects, modeling studies, 5) promotion of land use planning and 6) initiation of stocking and rehabilitation of the lakes. •

55

ADMINISTRATION

A new set of officials comprises AQD management. Dr. Rolando R. Platon was appointed AQD chief on 08 April 1996 at the 28th SEAFDEC Council Meeting in Chiangmai, Thailand. Mr. Yasuho Tadokoro, AQD Deputy Chief, was also appointed on 08 July 8 1996.

AQD's management includes the following heads of divisions:

1. Dr. Clarissa L. Marte, Head, Research Division

2. Mr. Renato F. Agbayani, Head, Training and Information Division

3. Mr. Dan D. Baliao, Head, Administration Division

4. Mr. Rene V. Alger, Head, Finance Division

At present. AQD's permanent staff is composed of 350 technical and support staff. As a response to new developments affecting AQD functions, the administration commissioned the Sycip. Gorrez, Velayo, Inc. (SGV), a Manila-based management consulting firm to develop a new AQD organizational structure. The proposal has been completed and will be submitted for approval by the SEAFDEC Council .

The SGV also reviewed the compensation scheme of A Q D to make it more commensurable. In addition, SGV developed a new Employee's Performance Appraisal System. Both schemes are being reviewed prior to implementation.

Infrastructure And Facilities Development

The major project in AQD's infrastructure development is the construction of the Integrated Fish Broodstock and Hatchery Pilot Demonstration Complex at Tigbauan Main Station.

This complex is intended to showcase AQD's fish breeding and hatchery technologies and to demonstrate to fish farmers and entrepreneurs the commercial viability of these technologies. The complex will be inaugurated on 09 July 1998, AQD's silver anniversary.

As of this writing. 20 projects were completed while 17 are ongoing.

Staff Development

AQD continued to assist its staff in obtaining advanced degrees. Ten staff members have completed their MS and PhD degrees in foreign and local universities. On the other hand, 11 are currently pursuing their studies.

PLATON TADOKORO

BALIAO ALGER

MARTE AGBAYANI

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ADMINISTRATION AQD 1996-1997 REPORT

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Summer Work Appreciation Program

AQD continued to implement the Summer Work Appreciation Program (SWAP), a national program for out-of-school-youth that provides opportunity for them to engage in productive endeavor during summer vacation. This was implemented in cooperation with the Department of Labor and Employment.

In 1996 and 1997, A Q D enlisted 141 young people from the Stat ions nearby municipalities. They assisted A Q D in various day-to-day activities ranging from research to administrative assignments.

Finance

AQD's 1996 and 1997 operations were financed by a total US$14,242,155 (Table 11). Of this amount, the Philippine Government contributed US$11,322,129 while the Government of Japan gave a share of US$1,426,025. The rest was in the form of grants and other income. Major contributors to the grants were the Japan International Cooperation Agency (JICA), the Bureau of Fisheries and Aquatic Resources (BFAR) of the Philippines, the Lonza AG of Switzerland, the University of Hohenheim of Germany, and the Food and Agriculture

Organization (FAO). Total expenses incurred amounted to US$12,720,384 (Table 12).

DA Secretary Salvador Escudero III (foreground} presides over the ground breaking ceremony of the Integrated Fish Broodstock and Hatchery Pilot Demonstration Complex at the Tigbauan Station. The complex (below) is currently under construction and will be inaugurated during the 25th anniversary of AQD on July 9. 1998.

57

ADMINISTRATION AQD 1996-1997 REPORT

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TTable 11 . Contr ibu t ions , g ran ts and o the r i n c o m e rece i ved , 1996-1997 (US$).

Item

Contributions Philippine Government Government of Japan

Sub-total

Grants Japan International Cooperation Agency (JICA) Bureau of Fisheries and Aquatic Resources (BFAR, Philippines) University of Hohenheim, Germany Lonza AG, Switzerland Food and Agriculture Organization (FAO) The Canadian High Commission, Singapore Australian Centre for International Agricultural Research (ACIAR) Department of Agriculture, Philippines

Amount

11,322,129 1,426,025

12,748,154

100,273 56,817 43,627 27,852 20,919 15,226 14,419 12,706

Philippine Council for Aquatic and Marine Research and Development (PCAMRD) 10,967 Technical Education for Skills Development Authority (TESDA, Philippines) D.A.K.A. - A.M.B.A., Denmark Tufts University, USA Rockefeller Brothers Fund, USA International Center for Living Aquatic Resources Management (ICLARM) Dr. Ali Abed, Kingdom of Saudi Arabia Hamlet Protein, Denmark Simon Fraser University, Canada Cantho University, Vietnam St. Mary's University, Canada Dr. S. Recto, RAFC, DA Region IV, Philippines

Sub-total Other income

Total

9,553 8,621 6,613 5,000 2,762 2,094 1,588 1,337 1,123

933 304

342,734 1,151,267

14,242,155

Table 12. Expenses incurred in 1996-1997 (in US$).

Item

By Budget Item Personnel Operating expenses Capital outlay

Total By Off ice/Division

Research Training and Information Administration Finance Office of the Chief

Total

Amount

8,233,178 2,797,260 1,689,946

12,720,384

6,153,176 1,479,798 3,576,283

693,224 817,903

12,720,384

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LOOKING AHEAD

As the third millennium approaches, AQD faces a continuous challenge in

helping attain food security for the region. The immediate future shall usher increasing demands for aquaculture technology for better yields through improved hatchery techniques, better feeds, and better health management.

Food security through aquaculture impinges on the lives and livelihoods of the regions fishfarmers. Developing technologies for efficient production of export crops shall have to be intensified. This way. the region's aquaculture industry can be more competitive in the global scene. More work needs to be done too, in generating technologies that address the small fisherfolk's poverty cycle. In some way. making the small fisherfolk produce more and earn more also contributes to the overall picture of food security.

In doing so. AQD is guided by the concern for technologies that do not degrade the aquaculture environment. This AQD intends to pursue with much vigor in its research and development activities.

The increasing demand for aquaculture technology and the pressing concerns of more people for more food that can be produced through an environment-friendly manner shall shape AQD's driving force in the next millennium.

59

ANNEX

AAQD research papers published in scientific journals and in proceedings, 1996-1997

Scientific Journals:

Agbayani RF, Hatch U, Belleza E. 1996. Economic analysis of prawn (Penaeus monodon) culture in the Philippines, I: Hatchery operations. Asian Fish. Sci. 8:191-200.

Alapide-Tendencia EV, Dureza LA. 1997. Isolation of Vibrio spp. from Penaeus monodon (Fabricius) with red disease syndrome. Aquaculture 154:107-114.

Alava VR, Kanazawa A. 1996. Effect of dietary fatty acids on growth of milkfish Chanos chanos fry in brackishwater. Aquaculture. 144:363-369.

Almendras JME. 1996. Plasma osmolality and chloride regulation in the sea bass Lates calcarifer. Isr. J. Aquacult.-Bamidgeh. 48:28-34.

Amar EC, Cheong RMT, Cheong MVT. 1996. Small-scale fisheries of coral reefs and the need for community-based resource management in Malalison Island, Philippines. Fish Res. 25:265-277.

Basiao ZU, Doyle RW, Arago AL. 1996. A statistical power analysis of the 'internal reference' technique for comparing growth and growth depensation of tilapia strains. J. Fish. Biol. 49:277-286.

Bautista MN, Subosa PF. 1997. Changes in shrimp feed quality and effects on growth and survival of Penaeus monodon juveniles. Aquaculture. 151:121-129.

Capinpin EC Jr., Corre KG. 1996. Growth rate of the Philippine abalone, Haliotis asinina fed an artificial diet and macroalgae. Aquaculture. 144:81-89.

Catacutan MR, Coloso RM. 1997. Growth of juvenile Asian seabass, Lates calcarifer, fed varying carbohydrate and lipid levels. Aquaculture 149:137-144.

Chavoso EAJ, Hurtado-Ponce AQ. 1995. Effect of stocking density and nutrients on the growth and agar gel of Gracilariopsis bailinae (Gracilariales, Rhotophyta). Philipp. Scient. 32:27-33.

de Castro TR. 1996. Agar yield gel strength and sulfate content in Gracilariopsis heteroclada farmed in brackishwater canals. Isr. J. Aquacult. - Bamidgeh. 48:94-98.

dela Peña LD, Koube H, Nakai T, Muroga K. 1997. Detection of Vibrio penaeicida in Kuruma prawn after transport. Fish. Pathol. 32:233-234.

Dhert P, Bombeo RB, Sorgeloos P. 1993. Use of ongrown Artemia in nursery culturing of the tiger shrimp. Aquacult. Int. 1:170-177.

Duray MN, Alpasan LG, Estudillo CB. 1996. Improved hatchery rearing of mangrove red snapper, Lutjanus argentimaculatus, in large tanks with small rotifer (Brachionus plicatilis) and artemia. Isr. J. Aquacult.- Bamidgeh. 48:123-132.

Duray MN, Estudillo CB, Alpasan LG. 1996. The effect of background color and rotifer density on rotifer intake, growth and survival of the grouper (Epinephelus suillus) larvae. Aquaculture. 146:217-224.

Duray MN, Estudillo CB, Alpasan LG. 1997. Larval rearing of the grouper Epinephelus suillus under laboratory conditions. Aquaculture. 150:63-76.

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ANNEX AQD 1996-1997 REPORT

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Duray MN. 1995. The effect of tank color and rotifer density on rotifer ingestion, growth and survival of milkfish (Chanos chanos) larvae. Phllipp. Scient. 32:18-26.

Eguia MRR. 1996. Reproductive performance of four red tilapia strains in different seed production systems. Isr. J. Aquacult. - Bamidgeh. 48:10-18.

Fermin AC, Bolivar EC, Gaitan A. 1996. Nursery rearing of the Asian sea bass Lates calcarifer, fry in illuminated floating net cages with different feeding regimes and stocking densities. Aquatic Liv. Resour. 9:43-50.

Fernandez RD, Tendencia EA, Leano EM, Duray MN. 1996. Bacterial flora of milkfish, Chanos chanos, eggs and larvae. Fish Pathol. 31:123-128.

Gapasin RSJ, Nelis HJ, Chair M, Sorgeloos P. 1996. Drug assimilation in the tissue of European sea bass (Dicentratrehus labrax) fry delivered orally through bioencapsulation. J. Appl. Ichthyol. 12:39-42.

Garcia LMaB. 1996. Bioactivity of stored luteinizing hormone-releasing hormone analogue (LHRHa) in sea bass, Lates calcarifer Bloch. J. Appl. Ichthyol. 12:91-93.

Golez NV, Kyuma K. 1997. Influence of pyrite oxidation and soil acidification on some essential nutrient elements. Aquacult. Engr. 16:107-124.

Guanzon NG Jr, Fukuda M, Nakahara H. 1996. Accumulation of agricultural pesticides by three freshwater microalgae. Fish. Sci. 62:690-697.

Guanzon NG, Nakahara H, Yoshida Y. 1995. Inhibitory effects of heavy metals on growth and photosynthesis of three freshwater microalgae. Fish. Res. 60:379-384.

Hatch U, Agbayani RF, Belleza E. 1996. Economic analysis of prawn (Penaeus monodon) culture in the Philippines, I: Grow-out operations. Asian Fish. Sci. 9:127-141.

Hilomen-Garcia GV. 1997. Morphological abnormalities in hatchery-bred milkfish (Chanos chanos Forsskal) fry and juveniles. Aquaculture 152:155-166.

Hurtado-Ponce AQ, Agbayani RF, Chavoso EAJ. 1996. Economics of cultivating Kappaphycus alvarezii using the fixed-bottom line and hanging-long line methods in Panagatan cays, Caluya, Antique, Philippines. J. Appl. Phycol. 8:105-109.

Hurtado-Ponce AQ, Pondevida HB. 1997. The interactive effect of some environmental factors on the growth, agar yield and quality of Gracilariopsis bailinae (Zhang et Xia) cultured in tanks. Bot. Mar. 40:217-223.

Kohno H, Ordonio-Aguilar R, Ohno A, Taki Y. 1996. Morphological aspects of feeding and improvement in feeding ability in early stage larvae of the milkfish Chanos chanos. Ichthyol. Res. 43:133-140.

Leano EM, Lio-Po GD, Dureza LA. 1996. Virulence and production of extracellular proteins (ECP) of Aeromonas hydrophila associated with the epizootic ulcerative syndrome (EUS) of freshwater fish. UPV J. Nutr. Sci. 1:30-38.

Loya-Javellana GN, Fielder DR. 1997. Developmental trends in the mouthparts during growth from juvenile to adult of the tropical freshwater crayfish, Cherax quadricarinatus von Martens, 1868 (Decapoda, Parastacidae). Invertebr. Reprod. Dev. 32:167-175.

Luhan MRJ. 1996. Biomass and reproductive states of Gracilaria heteroclada Zhang et Xia collected from Jaro, Central Philippines. Bot. Mar. 39:207-211.

Millamena OM, Bautista MN, Reyes OS, Kanazawa A. 1997. Threonine requirement of juvenile marine shrimp Penaeus monodon Aquaculture. 151:9-14.

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Millamena OM, Bautista-Teruel MN, Kanazawa A. 1996 Methionine requirement of juveniles tiger shrimp Penaeus monodon Fabricius. Aquaculture. 143:403-410.

Mil lamena OM, Bautista-Teruel MN, Kanazawa A. 1996 Valine requirement of postlarval tiger shrimp, Penaeus monodon Fabricius. Aquacult . Nutri. 2:129-132.

Millamena OM, Trino AT. 1997. Low-cost feed for Penaeus monodon reared in tanks and under semi-intensive and intensive conditions in brackishwater ponds. Aquaculture 154:69-78.

Peñaflorida VD , Golez NV. 1996. Use of seaweed meals from Kappaphycus alvarezii and Gracilaria heteroclada as binders in diets for juveni le shrimp Penaeus monodon. Aquaculture. 143:393-401.

Peñaflorida VD, Virtanen E. 1996. Growth, survival and feed conversion of juvenile shrimp (Penaeus monodon) fed a betaine/amino acid additive. Isr. J. Aquacult.- Bamidgeh. 48:3-9.

Pondevida HB, Hurtado-Ponce AQ . 1996. Assessment of some agarophytes from the coastal areas of Iloilo, Philippines. I. Seasonal variations in the biomass of Gracilaria changii, Gracilaria manilaensis, and Gracilariopsis bailinae (Gracilariales, Rhodophyta). Bot. Mar. 39:117-122.

Pondevida HB, Hurtado-Ponce AQ . 1996. Assessment of some agarophytes from the coastal areas of Iloilo, Philippines. II. Seasonal variations in the agar quality of Gracilaria changii, Gracilaria. manilaensis, and Gracilariopsis bailinae (Gracilariales, Rhodophyta). Bot. Mar. 39:123-127.

Primavera JH. 1996. Stable carbon and nitrogen isotope ratios of penaeid juveni les and primary producers in a riverine mangrove in Guimaras, Philippines. Bull. Mar. Sci. 58:675-683.

Primavera JH. 1997. Fish predation on mangrove-associated penaeids - the role of structures and substrate. J. Expt. Marine Biology and Ecology. 215(2):205-216.

Primavera JH. 1997. Socio-economic impacts of shrimp culture. Aquacult . Res. 28:815-827.

Quinitio GF, Caberoy NB, Reyes DM, Jr. 1997. Induction of sex change in female Epinephelus coioides by social control. Isr. J. Aquacult . - Bamidgeh 49:77-83.

Santiago CB, Gonzal AC. 1997. Growth and reproductive performance of the Asian catfish Clarias macrocephalus (Gunther) fed artificial diets. J. Appl. Ichthyol. 13:37-40.

Tambasen-Cheong MVO, Tan-Fermin JD, Garcia LMB, Baldevarona RB. 1995. Milt-egg ratio in artificial fertilization of the Asian freshwater catfish, Clarias macrocephalus, injected salmon gonadotropin-releasing hormone analogue and domperidone. Aquatic Liv. Resources. 8:303-308.

Tan-Fermin JD, Pagador RR, Chavez RC. 1997. LHRHa and pimozide-induced spawning of Asian catfish Clarias macrocephalus (Gunther) at different t imes during an annual reproductive cycle. Aquaculture 148:323-331.

Toledo JD, Golez SN, Doi M. Ohno A. 1997. Food selection of early grouper, Epinephelus coioides, larvae reared by the semi-intensive method. Suisanzoshoku. 3:327-337.

Trino AT, Sarroza JC. 1995. Effect of a diet lacking in vi tamin and mineral supplements on growth and survival of Penaeus monodon juveni les in a modified extensive culture system. Aquacul ture. 136:323-330.

PProceedings:

Agbayani RF, Siar SV. 1994. Problems encountered in the implementation of a community-based fishery resources management project. Pomeroy RS (ed.) Proceedings of the Workshop on Community Management and Common Property of Coastal Fisheries in Asia and Pacific:

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Concepts, Methods and Experiences; 21-23 June 1993; Silang, Cavite, Philippines. (ICLARM Conf. Proc. 45); Makati, Metro Manila, Philippines: International Center for Living Aquatic Resources Management; 149-160.

Borlongan IG, Coloso RM, Blum RA. 1996. Use of metaldehyde as molluscicide in milkfish ponds. Henderson IF (chaired). Slug and Snail Pests in Agriculture: Proceedings of a Symposium on Slug and Snail Pests in Agriculture; The University of Kent, Canterbury, U.K.; 24-26 September 1996. United Kingdom: British Crop Protection Council; 205-212.

Cruz-Lacierda ER, Shariff M. 1995. Experimental transmission of epizootic ulcerative syndrome (EUS) in snakehead, Ophicephalus striatus. Shariff M, Arthur JR and Subasinghe RP(eds.) Diseases in Asian Aquaculture II, Proceedings of the Second Symposium on Diseases in Asian Aquaculture; 25-29 October 1993; Phuket, Thailand: Manila, Philippines: Fish Health Section, Asian Fisheries Society; 327-336.

Duray MN. 1996. Larviculture of milkfish (Chanos chanos) in outdoor tanks. Marte CL, Quinitio GF, Emata AC. (eds.). Breeding and seed production of cultured finfishes in the Philippines. Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, 4-5 May 1993. Tigbauan, Iloilo, Philippines: SEAFDEC/AQD; pp. 150-158.

Emata AC. 1996. Maturation and induced spawning of the mangrove red snapper (Lutjanus argentimaculatus) reared in a floating net cage in the Philippines. Arrenguin-Sanchez F, Munro JL, Balgos MC, Pauly D. eds. Biology, Fisheries and Culture of Tropical Groupers and Snappers; Proceedings of an EPOMEX/ ICLARM International Workshop on Tropical Snappers and Groupers; 26-29 October 1993; University of Campeche, Campeche, Mexico; ICLARM Conf. Proc. 48; Manila, Philippines: ICLARM and EPOMEX; pp. 378-384.

Fermin AC, Bolivar MEC. 1996. Weaning of the As ian catfish, Clarias macrocephalus Gunther, larvae to formulated dry diet. Santiago CB, Coloso RM, Millamena OM, Borlongan IG. eds. Feeds for small-scale aquaculture, Proceedings of the National Seminar-Workshop on Fish Nutrition and Feeds; 1-2 June 1994; SEAFDEC /AQD, Tigbauan, Iloilo; Tigbauan, Iloilo, Philippines: SEAFDEC Aquacul ture Department; pp. 83-86.

Garcia LMaB. 1996. A review of S E A F D E C / A Q D finfish breeding research. Marte CL, Quinitio GF, Emata AC. (eds.). Breeding and seed production of cultured finfishes in the Philippines. Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, 4-5 May 1993. Tigbauan, Iloilo, Philippines: SEAFDEC/AQD; pp. 54-64.

Hurtado-Ponce A. 1995. Module III. Assessment of the seaweed industry. Achieving International Competit iveness through Technology Development Transfer Assessment Reports. DOST-UNDP Project; Manila, Philippines :Department of Science and Technology; United Nations Development Programme; 137-176.

Hurtado-Ponce AQ. 1996. Gracilaria studies at SEAFDEC AQD. Proceedings of the Regional Workshop on the Taxonomy, Ecology and Processing of Economically Important Red Seaweeds; Bangkok, Thailand; 24-25 Jan 1995. NACA Environment and Aquaculture Development Series No. 3; FAO /NACA; Bangkok, Thailand: Network of Aquaculture Centers in Asia-Pacific;pp.311-117.

Lavilla-Pitogo CR. 1996. Shrimp health research in the Asia-Pacific: Present status and future directions. In:Subasinghe RP, Arthur JR Shariff M. eds. Health Management in Asian Aquaculture; Proceedings of the Regional Expert Consultation on Aquaculture Health Management in Asia and the Pacific; FAO Fisheries Technical Paper No. 360. Rome: FAO, Fish Health Section of the Asian Fisheries Society; pp. 41-50.

Lavilla-Pitogo CR, Emata AC, Duray MN, Toledo JD. 1996. Management of fish health in broodstock and larvae of milkfish, sea bass , and grouper. Main KL, Rosefeld C. eds. Aquaculture Health Management Strategies for Marine Fishes. Proceedings of a Workshop on Aquaculture Heal th Management Strategies for Marine Fishes; 1995

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October 9-13; U.S.A., Hawaii: The Oceanic Institute;47-56. Tigbauan, Iloilo; Tigbauan, lloilo, Philippines: SEAFDEC Aquacul ture Department; pp. 52-63.

Lavilla-Pitogo CR. 1995. Bacterial diseases of penaeid shrimps: an As ian view. Shariff M, Arthur JR and Subasinghe RP(eds.) Diseases in Asian Aquacul ture II, Proceedings of the Second Symposium on Diseases in As ian Aquaculture; 25-29 October 1993; Phuket, Thailand: Manila, Philippines: Fish Health Section, Asian Fisheries Society; 107-121.

Leano EM, Lio-Po GD, Dureza LA*. 1995. Siderophore detection among bacteria associated with the epizootic ulcerative syndrome (EUS). Shariff M, Arthur JR and Subasinghe RP(eds.) Diseases in Asian Aquaculture II, Proceedings of the Second Symposium on Diseases in Asian Aquaculture; 25-29 October 1993; Phuket, Thailand: Manila, Philippines: Fish Health Section, Asian Fisheries Society; 315-325.

Marte CL, Quinitio GF, Emata AC . eds. 1996. Breeding and seed production of cultured finfishes in the Philippines. Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, 4-5 May 1993. Tigbauan, Iloilo, Philippines: SEAFDEC/AQD;pp . 182.

Millamena OM. 1996. Review of SEAFDEC /AQD fish nutrition and feed development research. Santiago CB, Coloso RM, Millamena OM, Borlongan IG. eds. 1996. Feeds for small-scale aquaculture. Proceedings of the National Seminar-Workshop on Fish Nutrition and Feeds; 1-2 June 1994; SEAFDEC /AQD, Tigbauan, Iloilo; Tigbauan, Iloilo, Philippines: SEAFDEC Aquaculture Department; pp.52-63.

Primavera JH, Agbayani RF. 1997. Comparative strategies in community-based mangrove rehabilitation programs in the Philippines. Hong PH, Ishwaran N, Thi San H, Hoang Tri N, Sy Tuan M. eds. Community Participation in Conservation, Sustainable Use and Rehabilitation of Mangroves in Southeast Asia. Proceedings of the ECOTONE V; 8-12 January 1996, Ho Chi Minh City, Vietnam; pp. 244-255.

Quinitio ET, Parado-Estepa F, Mil lamena OM, Biona H. 1996. Reproductive performance of captive Penaeus monodon fed various sources of carotenoids. Santiago CB, Coloso RM, Mil lamena OM, Borlongan IG. eds,. Feeds for small-scale aquaculture, Proceedings of the National Seminar-Workshop on Fish Nutrition and Feeds; 1-2 June 1994; SEAFDEC/ AQD, Tigbauan, Iloilo; Tigbauan, Iloilo, Philippines: SEAFDEC Aquaculture Department; pp. 74-82.

Quinitio GF, Coloso RM, Caberoy NB, Toledo JD. 1996. Egg quality grouper Epinephelus coioides fed different fatty acid sources. Mackinlay D, Eldridge M. (eds). The Fish Egg: Its Biology and Culture Symposium Proceedings. International Congress on the Biology of Fishes; 14-18 July 1996; U.S.A.: San Francisco State University; 103-107.

Quinitio GF, Duray MN. 1996. Review of SEAFDEC /AQD finfish seed "production research. Marte CL, Quinitio GF, Emata AC. (eds.). Breeding and seed production of cultured finfishes in the Philippines. Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, 4-5 May 1993. Tigbauan, Iloilo, Philippines: SEAFDEC/AQD; pp. 119-131.

Santiago CB, Coloso RM, Mil lamena OM, Borlongan IG. eds. 1996. Feeds for small-scale aquaculture. Proceedings of the National Seminar-Workshop on Fish Nutrition and Feeds; 1-2 June 1994; SEAFDEC /AQD, Tigbauan, Iloilo; Tigbauan, Iloilo, Philippines: SEAFDEC Aquacul ture Department; p. 144.

Toledo TD, Doi M, Duray M. 1996. Viability of milkfish eggs and larvae after simulated and actual transport. MacKinlay D, Eldridge M (eds.). The Fish Egg: its Biology and Culture Symposium Proceedings: International Congress on the Biology of Fishes; 14-18 July 1996; United States of America:San Francisco State University; 51-58.

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