Now showing items 2374-2393 of 3185

    • Conference paper

      Qualitative and quantitative comparison of bacterial flora associated with hatchery-reared and wild-caught shrimp postlarvae 

      CR Lavilla-Pitogo, LD de la Peña & MG Paner - In Proceedings of the International Workshop: Antibiotic Resistance in Aquaculture Environments, 24-25 February 2005, Chiang Mai, Thailand, 2005 - ASIARESIST
      Because of high mortality recorded in pond-reared shrimps due to luminescent vibriosis infection, a study was conducted to determine if postlarvae (PLs) could be major sources of luminescent bacteria (LB). Batches of hatchery-reared (PL12 to 18) and wild-caught Penaeus monodon PLs were examined to determine their bacterial load. Results show that although all PLs have associated Vibrio spp., not all of them harbored detectable levels of LB. Fifty eight percent of wild-caught postlarval batches did not have associated LB compared with only 23-44% of hatchery-reared postlarvae. A significant difference in quantitative LB load was noted between hatchery reared and wild-caught PLs with the former harboring up to 3.0 x 105 cfu LB/postlarva. Wildcaught PLs had only up to 3.5 x 102 cfu LB/postlarva. Antimicrobial sensitivity tests using disc diffusion method show significant resistance to Chloramphenicol and Oxytetracycline among isolates from hatchery-reared PLs (33 and 44%) compared with bacteria from wild-caught PLs (3 and 6%) and near shore seawater (0 and 12%). The differences between the quantitative and qualitative bacterial flora of hatchery-reared and wild-caught PLs may have contributed to the occurrence of luminescent vibriosis in grow-out ponds, which generally make use of hatchery-reared postlarvae.
    • Article

      Quality assessment of newly hatched mud crab, Scylla serrata, larvae 

      ET Quinitio, JJ dela Cruz-Huervana & FD Parado-Estepa - Aquaculture Research, 2018 - Wiley
      Starvation and exposure to formalin were investigated as possible stress tests for evaluating the quality of mud crab, Scylla serrata, larvae. For the starvation stress test, newly hatched zoeae stocked in 150-ml containers were either starved or fed rotifers. Similarly, newly hatched zoeae were stocked in containers with seawater of 0 (control), 20, 30 and 40 mg/L formalin for the formalin stress test. The zoeae from the same batches were used for seed production to monitor their performance and validate the results of stress tests. Starvation was found to be unsuitable for larval quality evaluation. However, the impact of initial food deprivation on the newly hatched larvae indicates that feeding immediately after hatching is necessary for mud crab larvae. Exposure of larvae to 40 mg/L formalin for 3 hr appeared to be a reliable and practical method for larval quality assessment as the survival of larvae in the mass production tanks validated the classification of good and poor quality batches in the stress tests. On this basis, a hatchery operator can decide which batch should be cultured further. Finally, there appears to be a link between the quality of larvae and the performance at the megalopa and early juvenile crabs.
    • Article

      Quality of hatchery-reared juveniles for marine fisheries stock enhancement 

      L Le Vay, GR Carvalho, ET Quinitio, JH Lebata, VN Ut & H Fushimi - Aquaculture, 2007 - Elsevier
      The potential for stock enhancement by release of hatchery-reared juveniles continues to be a topic of interest to researchers and fisheries managers. While, in many studies, the focus has tended to be on the technology for production of juveniles, the need for a more multidisciplinary approach is now becoming accepted. Ideally, this includes studies of population dynamics and recruitment-limitation of wild stocks, environment–stock interactions, habitat availability, genetic studies of wild and released stocks and integration with appropriate fisheries management. While it may be relatively straightforward to culture large numbers of seed animals, the quality of hatchery-reared juveniles may limit the effectiveness of any release programme. The quality of juveniles may be defined either by their ability to attain the age and size to recruit to a commercial fishery or their fitness to survive to contribute to the spawning stock. Many factors will inevitably influence batch–batch variability in the viability of hatchery-reared juveniles and their ability to recruit and compete in the wild. Some effects of nutrition and environment in the hatchery are well-known or at least recognised and their manipulation offers the potential for improvement of survivorship of juveniles post-release. The choice and utilisation of broodstock also represent a crucial stage in enhancement programmes, and considerations of bottleneck effects arising from reduced effective population size due to skewed parental and family contributions must be given careful consideration. A broodstock design that encompasses sufficient numbers of animals that reflect the genetic, and preferably ecological, identity of the stocks to be enhanced should be adopted. In addition, environmental conditions and husbandry practices within the hatchery as well as broodstock and larval nutrition can all influence the quality of offspring. Further conditioning and/or selection during nursery culture may also be critical in maximising the physiological and behavioural fitness of hatchery juveniles post-release. Although evaluation of long-term performance of individual batches of juveniles requires considerable effort or may be impossible in some cases, this type of quantification is likely to be an important component in the determination of the effectiveness of release programmes. This paper reviews the effects of hatchery and nursery practice on larval and juvenile fitness for stock enhancement and presents examples of comparisons of the quality of wild and hatchery-reared juveniles and the effect of pre-release conditioning on subsequent survival and growth.
    • Article

      Quantitative and qualitative analyses of the bacterial microbiota of tilapia (Oreochromis niloticus) cultured in earthen ponds in the Philippines 

      R Pakingking Jr., P Palma & R Usero - World Journal of Microbiology and Biotechnology, 2015 - Springer Verlag
      The quantity and composition of the bacterial microbiota in the rearing water, sediment, gills and intestines of tilapia Oreochromis niloticus collected every 2 weeks from Day 30 to Day 120 after stocking for grow-out culture in 6 earthen brackish water ponds in the Philippines were examined. The total heterotrophic aerobic bacterial counts obtained in the water, sediment, gills and intestines of tilapia ranged from 103 to 104 c.f.u. ml−1, 103–105, 105–107 and 104–107 c.f.u. g−1, respectively. In terms of composition, a total of 20 bacterial genera and 31 species were identified with the preponderance of gram-negative bacteria constituting 84% of all bacterial isolates examined. Aeromonas hydrophila, Bacillus spp., Plesiomonas shigelloides, Shewanella putrefaciens, Pseudomonas fluorescens, Staphylococcus spp. and Vibrio cholerae were the dominant bacteria identified in the gills and intestine of tilapia. These bacteria also dominated in the pond sediment and rearing water, except for the nil isolation of S. putrefaciens and V. cholerae in the water samples examined, indicating that resident bacteria in the pond water and sediment congruently typify the composition of bacterial microbiota in the gills and intestine of tilapia which under stressful conditions may propel the ascendance of disease epizootics.
    • Article

      The quantitative dietary protein requirements of Penaeus monodon juveniles in a controlled environment 

      VR Alava & C Lim - Aquaculture, 1983 - Elsevier
      Penaeus monodon juveniles (average weight = 1.32 g) were kept in individual 2 l perforated plastic containers, 10 of which were placed in each of the twenty-four 50 l rectangular wooden-glass aquaria supplied with seawater filtered through a sand-gravel filter (32–34 ppt; 26.5–29.0°C; pH, 7.6–8.2) at 0.8–1.01 l/min. Eight diets were prepared containing 25–60% protein and fed at 10% of the body weight/day for the first 2 weeks and 8% for the succeeding 4 weeks.

      Shrimps fed the 40% protein diet produced the best growth, feed conversion ratio (FCR), protein efficiency ratio (PER) and survival rate. However, shrimps fed the 30, 35 and 45% protein diets produced comparable results. The protein content of the shrimps was directly related to the level of protein diet up to 50%; whereas fat content seemed to be inversely related up to 50% protein diet.
    • Article

      Quantitative dietary requirements of postlarval tiger shrimp, Penaeus monodon, for histidine, isoleucine, leucine, phenylalanine and tryptophan 

      OM Millamena, MB Teruel, A Kanazawa & S Teshima - Aquaculture, 1999 - Elsevier
      The quantitative requirements of postlarvae Penaeus monodon for essential amino acids were determined through a series of feeding experiments. Test diets contained casein–gelatin as natural proteins supplemented with crystalline L-amino acids (CAAs) at levels based upon the tissue amino acid profile of postlarvae tiger shrimp. Each set of experimental diets contained graded levels of the test amino acid in a range below and above those found in shrimp muscle protein. The dietary CAA mixture was pre-coated with carboxymethylcellulose (CMC), and the diets were additionally bound with CMC, corn starch, and K-carrageenan to prevent leaching of amino acids and other nutrients. P. monodon postlarvae, PL20, mean body weight of 20 mg, were randomly distributed to 30-l fiberglass tanks at a density of 10/tank and each group was fed a particular diet for 56 days. A one-way analysis of variance was used to determine if there were any significant differences in weight gain, survival, and feed conversion among the dietary treatments for each experiments. Regression analysis of the weight gain responses against dietary amino acid levels was used to estimate the amino acid requirements. The optimum dietary requirements for essential amino acids, in percent of the diet, were: 0.8% histidine, 1.01% isoleucine, 1.7% leucine, 1.4% phenylalanine, and 0.2% tryptophan. Expressed as percent of the dietary protein, the requirement values were: 2.2% histidine, 2.7% isoleucine, 4.3% leucine, 3.7% phenylalanine, and 0.5% tryptophan. This information is crucial in optimizing growth and feed efficiency and in developing cost-effective diets for P. monodon.
    • Article

      Quantitative lysine requirement of milkfish (Chanos chanos) juveniles 

      IG Borlongan & LV Benitez - Aquaculture, 1990 - Elsevier
      A feeding experiment was conducted to determine the quantitative dietary requirement of milkfish juveniles for lysine. Milkfish (Chanoschanos Forsskal) of mean weight 5.92±0.14 g were fed diets containing 7.0, 11.0, 15.0, 19.0, 23.0 and 27.0 g lysine/kg dry diet for 12 weeks. The amino acid test diets contained white fish meal and zein supplemented with crystalline amino acids to provide an amino acid profile similar to milkfish proteins except for lysine. Each of the six diets was fed to four replicate groups of 25 fish in a completely randomized design and at a feeding rate of 5% of the fish body weight per day. On the basis of the growth response, lysinerequirement of juvenile milkfish was found to be 20 g/kg diet. This value corresponds to 4.0% when expressed as a percentage of the dietary protein. Survival (94–97%) was consistently high in all treatments. Except for loss of appetite resulting in low food intake and depressed growth, no nutritional deficiency signs were observed in fish given the lysine-deficient diets.
    • magazineArticle

      Quo vadis, shrimp? 

      Southeast Asian Fisheries Development Center, Aquaculture Department - Aqua Farm News, 1996 - SEAFDEC Aquaculture Department
      The paper discusses the shrimp culture practices of Thailand, the top producing country of cultured shrimp. These shrimp culture techniques include the use of reservoirs for better waste management, utilization of undiluted seawater for culture, low-cost pumping systems, measures to neutralize acid sulfate soils, proper treatment of pond bottom, and solutions to disease problems.
    • Book chapter

      The rabbitfishes 

      MN Duray & JV Juario - In CE Nash & AJ Novotny (Eds.), Production of aquatic animals: fishes, 1995 - Elsevier
    • Book

      Raft culture of mussels 

      HS Sitoy, AL Young & MY Tabbu - 1983 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 8
    • Conference paper

      Rapid adaptation to a new environment: is it reversible? 

      H Araki - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Accumulating evidence suggests rapid adaptation of fish populations when they are exposed to artificial hatchery environments. However, little is known if rapidly-adapted populations can readapt to their original, natural environment at the same rate. Here, I review recent studies on salmonid fish that address this issue. They indeed suggest rapid adaptation of hatchery populations, in which reproductive fitness under a natural environment became much lower than that in the wild population after only 1-2 generations of captive breeding. However, the reproductive fitness did not recover after one generation of natural rearing, implying that rapid adaptation to a new environment was not reversible at the same rate. I discuss potential consequences of the irreversible fitness reduction in extensively stocked fish species. Understanding the mechanism behind the irreversible rapid adaptation in fish populations will help us figure out a better, nature-friendly, and hence sustainable means of hatchery operations for human welfare.
    • Article

      Rapid rural appraisal and participatory research in the Philippines 

      WG Gallardo, VC Encena II & NC Bayona - Community Development Journal, 1995 - Oxford University Press
      Rapid Rural Appraisal (RRA) was conducted in the fishing village of Lakaran, in the municipality of Dumangas, Iloilo province to identify the resources, livelihood, problems, opportunities, and socioeconomic condition of the villagers prior to the conduct of farmer participatory research on mussel farming. RRA tools such as the construction of the village transect, seasonal calendar and wealth ranking were used.
    • Article

      Rapid wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid 

      G Erazo-Pagador & MS Din - The Israeli Journal of Aquaculture-Bamidgeh, 2001 - Society of Israeli Aquaculture and Marine Biotechnology
      Wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid was studied under laboratory conditions. Fish weighing approximately 80-110 g were stocked in 500 l aquaria in a static water system and fed one of five test diets containing different levels of microencapsulated ascorbic acid (0, 0.06, 0.10, 0.30 and 0.70 g AsA/100 g feed). After two weeks, all experimental fish were wounded by making a 1 x 1 cm dorso-lateral incision above the lateral line of the fish. Wounded tissues were sampled for histopathological analysis 4, 8, 24, 48 and 96 hours, 6, 8, 10, 12 and 14 days after making the incision. There were significant differences in weight gain, specific growth rate (SGR) and feed conversion ratio among the dietary treatments. Weight gain and SGR of fish fed the ascorbic acid free diet were lower than those of fish fed diets supplemented with ascorbic acid. The wound healing response showed a direct correlation to ascorbate level in the diet. Fibroblasts were present at 96 h irrespective of the ascorbic acid level. As 14 days, fish fed no ascorbic acid had some regeneration of muscle tissues, whereas fish fed diets containing supplemental ascorbic acid had a normal epidermis, dermis and muscle structure. There was no mortality during the experimental period, and fish fed ascorbic acid free diets did not exhibit any deficiency signs. Results of this study indicate that about 0.10-0.70 g AsA/100 g feed is needed for wound repair in African catfish.
    • Conference paper

      Reaching the poor through aquaculture: The case of technology adoption in rural communities at west central Philippines 

      DB Baticados - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Aquaculture is promoted for food security and poverty alleviation in developing countries. This study examines the socio-economic impact of aquaculture technologies extended to calamitystricken rural communities in Nueva Valencia, Guimaras, representing the marine water fishery and in Dumarao, Capiz, representing the inland freshwater fishery at west central Philippines. The adoption pathway employed in both sites was community-based and participatory. The survey was conducted among cooperators and non-cooperators, randomly selected in equal numbers in two sites with 60 respondents each per site using a pre-tested interview schedule.

      Results showed that aquaculture is an acceptable technology both for cooperators and noncooperators. The venture is a profitable business either done individually or collectively through an association, if managed properly. Milkfish cage culture, however, needs big capital that technology adoption among local fisherfolk (Guimaras) is limited. In contrast, tilapia cage culture enables small farmers/fishers in Dumarao to venture on their own. Dumarao growers were able to innovate using local materials like bamboo poles to make their cages afloat instead of drums or plastic containers as buoys. There were, however, environmental, technological and institutional issues deterring technology adoption in both sites. Climate change and institutional issues were the more prevalent concerns of Dumarao growers. The technological issues like fluctuating market price, cost of feeds, and fry supply were more enunciated in Guimaras.
    • magazineArticle

      Realizing green aquaculture 

      AP Surtida - SEAFDEC Asian Aquaculture, 2000 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Rearing of the larval stages of prawn, Penaeus japonicus Bate, using artificial diet. 

      CT Villegas & A Kanazawa - Memoirs of the Kagoshima University Research Center for the South Pacific, 1980 - Kagoshima University Research Center for the South Pacific
      Survival and growth rates of the zoeal and mysis stages of the prwn, Penaeus japonicus Bate, were studied using natural and artificial diets.

      The highest survival rate, 34.2%, was obtained in the larvae fed with the artificial diet, Diet-B. Larvae fed with the diatom, Chaetoceros gracilis, plus Artemia nauplii did not give the best survival; however, growth was the fastest in this group. The larvae metamorphosed into the mysis3 stage in 8 days. The results thus seem to demonstrate tat Diet-B is an effective diet for the early larval stages of the prawn, P. japonicus.
    • Conference paper

      Recent Asian initiatives under the NACA regional programme on aquatic animal health management 

      MG Bondad-Reantaso - In Y Inui & ER Cruz-Lacierda (Eds.), Disease Control in Fish and Shrimp Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques: Proceedings … Aquaculture in Southeast Asia - Diagnosis and Husbandry Techniques, 4-6 December 2001, Iloilo City, Philippines, 2002 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The activities of NACA in support of improving aquatic animal health management within Asia dates back since 1986 when it was first involved in the UNDP/FAO/ODA (and subsequently DFID) sponsored program on Epizootic Ulcerative Syndrome (EUS). Consequently, in cooperation with relevant governments and institutions, NACA implemented a Regional Research Program on Ulcerative Syndrome in Fish and the Environment, from 1986 to 1989, which produced most of the scientific data on environmental parameters associated with EUS outbreaks in the Asia-Pacific region. Between 1989-1990, NACA and ADB implemented the Regional Study and Workshop on Fish Disease and Fish Health Management which revealed a scenario of environment-linked disease problems, product contamination, and environmental impacts on aquaculture, and for the first time losses suffered by Asian aquaculture from fish diseases were quantified. The study provided the first broad guidelines to regional and national strategies for developing capacities in fish health management. In 1991, OIE Tokyo approached NACA to initiate cooperation with respect to aquatic animal disease reporting which eventually led to an Expert Consultation on Aquatic Animal Disease Reporting in 1996. Between 1992 to 1996, NACA was involved in the following regional activities: (a) collaborating with IDRC and UPM in a Tropical Fish Health Management course, that ran for two intakes of students at UPM; (b) participating in the FAO 1994 Expert Consultation on Health Management held at UPM in Malaysia; and (c) the 1996 Consultation on Quarantine and Health Certification of FAO and AAHRI through the ODA-funded SEAADCP project. In l998, a joint publication - 'EUS Technical Handbook' with ACIAR, DFID, NSW Fisheries, AAHRI through SEAADCP and NACA - was completed.

      The major recommendations of the various regional meetings/consultations became the basis for the development of a strong multi-disciplinary Asia-Pacific regional programme on aquatic animal health management. At the request of Asian governments, NACA and FAO developed a Regional Technical Cooperation Programme on "Assistance for the Responsible Movement of Live Aquatic Animals" (FAO RTCP/RAS 6714 and 9605). The project was implemented from 1998 to 2001 in cooperation with 21 governments/territories in Asia-Pacific region, OIE FDC, OIE Tokyo, AFFA, AusAID/APEC and AAHRI.

      The programme and its outputs were developed through three years (1998 to 2001) of awareness raising and consensus building through various national and regional level activities (e.g. workshops, training courses, expert consultation, health assessments, etc.). This multidisciplinary Regional Aquatic Animal Health Management Programme has now been adopted by Asian governments (including NACA members and participating governments within ASEAN) as an important element of NACA's Third Five Year Work Programme (2001-2005). The current thrust of the programme is to assist countries in implementing the 'Technical Guidelines', giving special emphasis to the concept of "phased implementation based on national needs", including monitoring and evaluation of its implementation. One of the mechanisms to support Asian governments in the implementation of the 'Technical Guidelines' is through regional cooperation where effective partnership with relevant organizations will be continuously established and strengthened. Designated National Coordinators will continue to be the focal points for its implementation.

      A Regional Advisory Group on Aquatic Animal Health has been established which will function as an official regional expert group that will ensure the provision of expert advice to Asian governments in the implementation of the 'Technical Guidelines', with NACA providing institutional support and FAO and OIE providing technical guidance. The main elements for regional cooperation include: (a) Promoting effective cooperation through regional resource centers on aquatic animal health; (b) Harmonization of procedures for health certification, quarantine and diagnostics; (c) Support to capacity building; (d) Awareness raising, communication and information exchange on aquatic animal health; (e) Regional disease reporting; (f) Emergency response; and (g) Joint activities for risk reduction in shared watersheds.The paper also briefly include other health related projects jointly being developed and/ or currently carried out by NACA with other organizations (e.g. ACIAR, APEC, ASEAN, CSIRO, DANIDA, IDRC, MPEDA, MRC and SEAFDEC-AQD).
    • Conference paper

      Recent developments and enhancing transfer of the nursery technology for the mud crab Scylla serrata 

      FD Parado-Estepa, V Alava, E Garibay, C Bejemino, J Sumile, J Silvestre & ET Quinitio - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The development of hatchery techniques for seed production of mud crab is expected to address the present problem on the depletion of wild seedstock supply for stocking in grow-out ponds. The nursery serves as the link between the two phases of culture as this involves growing of juvenile crabs produced in the hatchery to sizes that are suitable for stocking in the ponds.

      Nursery rearing involves the use of net cages installed in ponds as holding system for ease in harvest and retrieval of crabs. In the first nursery phase, 0.3-0.5 cm carapace width (CW) juvenile crabs are reared to 1.5-2.0 cm CW for 3-4 weeks and stocks are harvested for selling or are grown further in a second nursery phase in which crabs reach 2.5-3.0 cm after another 3-4 weeks. This paper includes a review of techniques initially developed for the nursery and more recent refinements which involve the use of higher crab instar densities, provision of suitable shelters, trimming of claws and sorting. In addition, production results in farms of collaborators are presented to highlight the efficiency of dissemination and also discusses the challenges faced by the potential nursery industry.
    • Conference paper

      Recent developments in aquaculture in Japan 

      K Fukusho - In TU Bagarinao & EEC Flores (Eds.), Towards sustainable aquaculture in Southeast Asia and Japan: Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia, Iloilo City, Philippines, 26-28 July, 1994, 1995 - SEAFDEC Aquaculture Department
      Aquaculture production in Japan in 1993 was 1,351,000 tons, 15.6% of the total fisheries production. About 93.6% came from mariculture and 6.4% from freshwater aquaculture. The per cent contribution of aquaculture to total production has increased in recent years but partly because marine fisheries,especially of sardine and pollack, have decreased. Aquaculture has reached a plateau, and decreased slightly between 1992 and 1993. Diverse marine and freshwater species are cultured in Japan — various fishes, crustaceans, mollusks, seaweeds, sea squirt, sea urchin, and others. Research and development in mariculture focus on finding substitutes for animal protein in feeds, improvement of fish quality, protection of the culture environment, use of offshore floating culture systems, and protection from diseases. Research in freshwater aquaculture has expanded to include recreational fishing, the propagation and preservation of endangered species, and the construction of fish ladders for salmonids and other migratory species.
    • Conference paper

      Recent developments in design and management of small-scale hatchery for Penaeus monodon in the Philippines 

      PG Gabasa Jr. - In Working Party on Small-Scale Shrimp/Prawn Hatcheries in Southeast Asia, Semarang, Central Java, Indonesia, 16-21 November 1981, 1982 - South China Sea Fisheries Development and Coordinating Programme
      It is a common belief that the zoea of Penaeus monodon are completely filter feeders. Thus, diatoms like chaetoceros and phytoflagellates are maintained at high feeding densities as much as 80 000 cells/ml in hatchery tanks during the zoeal states of the P.monodon. This feeding scheme often results in the reddening of the larvae followed by weakening, loss of appetite and eventual mass mortality.

      It was found out recently that zoea larvae are not completely filter feeders. It was observed as early as Zoae 1, the mouth parts of the larvae are already functional and can eat food particles as big as Artimeia and Brachionus.

      Based on this observation, a new feeding scheme was developed. Boiled egg yolk is fed to the larvae at 15-22 particles (as big as Brachionus) per ml from Zoea 2 to Mysis 3 stages. Tetraselmis is given from Zoea 1 to Mysis 3 stages at a low density level of 5 000 cells/ml. Artemia is also fed at 10-15 individuals/ml from Mysis 1 to Postlarvae 5. If Tetraselmis is not available, bread yeast is given from Zoea 1 to 3 at 0.1-03 g/ton as supplementery feed. With this new feeding scheme, the hatchery producers have been greatly simplified considering that the most difficult and tedious part in larval rearing is the maintenance of algal food especially diatoms.

      This feeding scheme was tested in a private hatchery in Bataan, Aklan province by the SEAFDEC Aquaculture Department from July to October 1981. All 44 runs were successful, yielding survival rates ranging from 22 to 75 percent and an average rate of 52.9 percent.

      The hatchery system was further simplified when experiments at the Bataan Substation of the SEAFDEC AQD revealed that as high as 60 percent survival can be attained with minimal aeration. Instead of centralized aeration system using compressors or blowers, portable aquarium-type aerators (5-watt) could be use thus minimizing energy consumption.

      Based on these developments, a new model for a small-scale hatchery system is proposed.

      based