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Southeast Asian Fisheries Development Center Aquaculture Department SEAFDEC/AQD Institutional Repository http://repository.seafdec.org.ph Journals/Magazines SEAFDEC Asian Aquaculture 1997 SEAFDEC Asian Aquaculture Volume 19(4) October 1997 Aquaculture Department, Southeast Asian Fisheries Development Center http://hdl.handle.net/10862/802 Downloaded from http://repository.seafdec.org.ph, SEAFDEC/AQD's Institutional Repository B405342 AsianAquaculture In this issue Seabass Culture inside AQD News and R&D Updates, p 2 AQD journal publications, p 6 Nature matters by TU Bagarinao, p 9 People in aquaculture SEAFDEC Sec-Gen Udom Bhatiyasevi, p 11 Stamps: a hobby of 2 biologists, p 12 Aquafarm news / special feature SEABASS CULTURE, p 13 Introduction, p 13 The culture of seabass, p 14 AQD's breeding-hatchery techniques, p 18 A feed for seabass, p 23 The seabass market, p 25 Lessons from Australia, Malaysia and Thailand, p 27 Postscript, p 29 Aquaculture clinic, p 30 AQD's 1998 training courses, new publications, p 34 ON THE COVER A bountiful harvest of seabass in Iloilo PHOTO By R Buendia A publication of the Aquaculture Department of the Southeast Asian Fisheries Development Center Volume XIX Number 4 October 1997 ISSN 0115-4974 Aquaculture Department NEWS, R&D UPDATES AQD cited for best research TWO AWARD-WINNING PAPERS EXCERPTED BELOW Intensive tilapia cage in Sampaloc Lake suggests that farming may cause growth of fish is confined between the surface and 2 m depth layer. Be- the death of low this depth, the water quality is Sampaloc Lake unfit for fish culture. For Sampaloc Lake to recover, By MB Surtida the study recommends a morato- The paper by AQD researcher rium on feeding and reduction of Alejandro Santiago and Rene total cage area. Based on the find- Arcilla tilled Tilapia cage culture ings that cage area and tilapia and the dissolved oxygen trends growth rate are related, a 5 ha cage in Sampaloc Lake, Philippines area will yield a tilapia growth in- published in the journal Environ- crement on natural food to be mental Monitoring and Assess- 0.838g per day and 0.699g per day ment Vol. 24, No. 3, pp 243-255, at 10 ha. A 5-gram tilapia fingerling won the 11th Dr. Elvira Tan Me- should grow to market size of 150 morial Award for 1997 in the g and 120 g in 6 months at 5 ha and aquaculture category. The paper 10 ha respectively. discussed Sampaloc Lake vis-a- The study has two recommen- vis the use of aquaculturists and dations for the recovery and reha- Sampaloc Lake in northern Philippines: x indicates sampling other users. station, boxes are tilapia cages [map from the Envi. Monitor. bilitation of the Sampaloc Lake. (1) The tilapia floating cage cul- Assess. 24(3): p. 245] A master plan should guide the re- ture industry in Sampaloc Lake duction of fish cages in Sampaloc (for open fishery and tilapia aquaculture, or a total 5,250 tons from the 28 ha cage Lake as approved by big and small opera- sec illustration) has expanded from 6 hec- area. Uneaten feeds being unavoidable in tors. (2) Powerful aerators in the middle of tares in 1981 to 28 ha in 1989. But occur- intensive cage farming, potential feed loss the lake should be installed to temporarily rences of fish kills with an estimated loss ranges between 157.5 and 1,575 tons (esti- solve the oxygen depletion. This will break of 1.2 million pesos aroused national con- mated at 5-30% total feed input). the thermal layering and aerate the water. cern over the conditions of Sampaloc Lake If the lost feed can be considered as But a civil or sanitary engineer must first and prompted investigations. sewage organic matter then the theoretical be consulted. Investigations showed that as the demand for oxygen is 249 to 2488 tons tilapia operations intensified, commercial annually. This estimate does not include the fish feeds were used. Cages measuring 10 total amount of fish feces and fish respira- Soybean oil improves x 20 x 5 meters (the most common size) tion which also extract oxygen from the reproductive performance with 3,150 pieces tilapia consume 1.25 tons lake. of commercial feeds for 120 days cropping. The pattern of oxygen depletion (<1 of Nile tilapia The feeds are broadcast or placed in feed- milligram per liter) shows the slow biologi- ing trays. Fish yield at 95% recovery is 0.6 cal death of the lake for fishery. What is By ET Aldon tons with fish averaging 200 g each. left in the lake for aquaculture is the upper "Lipid source affects the reproductive per- Extrapolated per hectare, the total 2 m because critical oxygen tension for formance of Nile tilapia and soybean oil is feeds delivered per cropping is 62.5 tons. tilapia is around 3 ppm. The present dis- the best lipid source," reports Dr. Corazon Thus the lake receives 187.5 tons per ha solved oxygen level and saturation value Santiago and Ofelia Reyes in their research 2 SEAFDEC Asian Aquaculture Vol XIX No. 4 October 1997 aqd news, r&d updates paper titled Effects of dietary lipid source The first graduates of the revised Coastal Aquaculture and Resource Management on reproductive performance and tissue training course pose with AQD Chief Dr. Rolando Platon (seated, 4th from the left) and lipid levels of Nile tilapia Oreochromis Training and Information Head Renato Agbayani (seated, 2nd from right). niloticus (Linnaeus) broodstock. In their experiment, Nile tilapia were fed diets with one of the following lipid sources at 5% level: cod liver oil, corn oil, soybean oil, a coconut oil-based cooking oil, or a combination of cod liver oil and corn oil (1:1). The control diet had no lipid supplement and had fish meal and soybean as protein sources. Their results showed that supplemen- tal lipid sources in the diets, corn oil, and the coconut-based cooking oil increased at varying degrees the number of females that spawned, number of fry per spawning, and total number of fry per spawner. The total fry production was markedly high for fish fed the soybean oil diet. This shows that high production in tilapia hatcheries may be achieved not only by increasing spawn- AQD improves curriculum of the coastal ing frequency but also increasing the number of females that spawn. aquaculture training course Data on gonadosomatic index (GSI), hepatosomatic index (HSI), and weight By AP Surtida gain showed no significant differences AQD revised the curriculum of the two- The curriculum changes are: among treatments. Fish fed the cod liver month training course on Coastal Aqua- • discussion of the conceptual framework oil has a poor reproductive performance but culture, adding a new module on coastal for coastal resource management is comparable with fish in all treatments in resource management. The changes are in • the new module on coastal resource terms of GSI and HSI and gave the highest response to the need for reconciling tech- management includes ten lecture weight gain. nology with the sustainability of develop- topics: (1) resource assessment and Fat content of liver and gonads of Nile ment. management; (2) coastal ecosystems tilapia broodstock was much higher than The training course results from the and biodiversity; (3) mangrove that of the muscle. However, fat levels in collaboration of the Governments of Japan management and silviculture; (4) fish liver, ovaries and testes as well as the GSIs and the Philippines. AQD conducts the sanctuary and marine reserves; (5) and HSIs did not clearly indicate which course with the support of the JICA Third socioeconomic considerations in dietary treatment enhanced reproduction. Country Training Programme. The course sustainable aquaculture; (6) Nile tilapia fingerlings given vegetable oils is held once during the Japanese fiscal year community organization and reportedly had better weight gain and feed 1994 to 1998. efficiency than those given beef tallow or next page pollack liver oil. However, Santiago re- ported that broodstock fed vegetable oils for essential fatty acids and energy for Nile This paper published in the Journal of influenced reproductive performance of tilapia broodstock diet. Applied Ichthyology, Vol. 9 (1993) pp 33- mature fish. The study was conducted at AQD's 40 won for the authors a special award dur- Santiago also noted that supplemental Binangonan Freshwater Station where stud- ing the 11th Dr. Elvira O. Tan Memorial oils may not be necessary if adequate lev- ies on freshwater species are done. San- Awards. The award is annually given by els of residual oils rich in n-6 fatty acids tiago, a scientist, holds a Ph.D. in Fisher- the Philippine Council for Aquatic Marine and n-3 fatty acids can be provided by the ies and Allied Aquacultures from Auburn Resources and Development (PCAMRD) major feed ingredients. Among the vegeta- University (USA) while Reyes, an associ- in recognition of Dr. Tan's contribution to ble oils tested, soybean oil is the best source ate researcher, holds an MS in Aquaculture aquaculture development. from the University of Ghent (Belgium). SEAFDEC Asian Aquaculture Volume XIX No. 4 October 1997 3 aqd news, r&d updates institutional building of fisherfolk cooperatives; (7) management of cooperatives; (8) property rights in fisheries; (9) institutional and policy analysis of coastal resource manage- ment: and (10) economic resource valuation. • addition of abalone to the lecture on mollusc culture. This reflects the strides AQD has taken in abalone R&D. Abalone culture is discussed alongside oyster, mussel and giant clam culture. The training course has a new name, Coastal Aquaculture and Resource Man- agement. The course is aimed at providing par- ticipants from Asian countries the oppor- tunity to improve knowledge and tech- AQD on the move niques of coastal aquaculture and resources management anchored on sustainable de- velopment.