Now showing items 1-10 of 10

    • Conference paper

      A brief account of the experience of Sabah Fisheries Department in fish larval rearing 

      CF Komilus & FD Parado-Estepa - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Venturing into the aquaculture sector especially in pond and cage culture is a step that has been taken up by entrepreneurs and traditional fishermen of Sabah. However, shortage in the supply of fish fry is a stumbling block to the progress of the industry.

      The Sabah Fisheries Department has taken steps to overcome this problem by setting up a hatchery with the objectives to transfer know-how on hatchery technologies to the private sector besides producing fry for distribution.

      The Tanjong Badak multi-species hatchery is a newly established hatchery, completed in mid-1990. The species reared for production purposes are tiger shrimp and finfish which include red snapper, grouper, sea bass and polkadot grouper. The Department has not close to producing sea bass fry. Shrimp fry at juvenile stages (PL 40) are distributed as subsidies to local fish farmers while some are reared at the Department's various cage and pond culture projects. Limited success in producing grouper and red snapper fry have been achieved to date. The incidence of very low fertilization rates of eggs coupled with low survival rates are major problems facing the hatchery.

      In conclusion, the Sabah Fisheries Department's experience in fish larval rearing is still limited. Greater scientific research and studies need to be carried out to improve further the performance of the hatchery to achieve the target of fry sufficiency for the aquaculture industry.
    • Conference paper

      Effects of different fat sources on the egg quality of grouper, Epinephelus suillus 

      GF Quinitio, RM Coloso, A Duller & D Reyes - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The effect of different fat sources on the egg quality of grouper, Epinephelus suillus eggs was evaluated. Fish in three tanks, each containing 3 females and 1 male, were fed various types of feeds namely: trash fish (control), trash fish + cod liver oil (treatment 1) and trash fish + SELCO, a lipid emulsion containing high levels of highly unsaturated fatty acid (HUFA) (treatment 2).

      Approximately 77.9 million eggs spawned from January to October 1992 by the control group, 40.0 million by fish in treatment 1, and 36.4 million by the treatment 2 group. Egg production (0.45 million eggs/kg BW) among the control group was significantly higher than treatment 2. Egg production of treatment 1 (0.06-0.36 million eggs/kg BW) was not significantly different (P<0.01) from the control group nor treatment 2 (0.02-0.30 million eggs/kg BW). Fertilization and hatching rates showed significant differences among the three groups with control > treatment 1 > treatment 2. There were no differences detected in the egg and oil globule diameters among the treatments. Crude protein and lipid levels of floating (good) and sinking (bad) eggs collected in February to March 1992, and August to September 1992 were similar in all treatments. Unfed larvae from treatment 1 survived until the fifth day after hatching while those in the control and treatment 2 groups lasted only until the third day. These results suggest that supplementation of cod liver oil and SELCO in the trash fish diet of E. suillus broodstock does not influence egg production, fertilization and hatching rates, and egg quality.
    • Conference paper

      Feeding habits of hatchery-reared grouper, Epinephelus suillus larvae 

      MN Duray - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The feeding habits of hatchery-reared Epinephelus suillus larvae were determined by examining their gut contents. The larvae (2.6 mm TL) were initially fed rotifers on day 2 and newly-hatched Artemia nauplii on day 21 (9.1 mm TL). The amount of rotifers initially ingested averaged 1.3 individuals/larva. The ingestion rate increased as larvae grew. Larvae immediately showed strong preference for Artemia to rotifers on the first day of introduction. E. suillus larvae showed diurnal feeding pattern at day 7 (3.6 mm TL), day 14 (4.9 mm TL), day 21 (9.1 mm TL) and day 28 (11.1 mm TL). Feeding incidence decreased in the evening and was nil at 2100-2200 h. Active feeding started earlier in older larvae and satiation was between 0900-1000 h. The results of this study will be used as a basis in developing a good feeding scheme for E. suillus larvae.
    • Conference paper

      Flounder metamorphosis: its regulation by various hormones 

      EG de Jesus, T Hirano & Y Inui - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The elongation and shortening of the flounder fin rays during its metamorphosis may be parallel to the appearance and resorption of the tadpole tail during amphibian metamorphosis. The dorsal fin rays of the Japanese flounder (Paralichthys olivaceus) elongate during the time when thyroid hormone levels are low and are resorbed during climax of metamorphosis when thyroid levels are elevated. Using an in vitro system for culture of isolated flounder fin rays, we examined how various hormones affect the process of resorption. Both T4 and T3 directly stimulated fin ray shortening, T3 being more potent than T4. Other hormones did not directly affect the resorption process but modified the tissue's response to thyroid hormones. Cortisol enhanced the stimulatory effects of both T4 and T3. On the other hand, estradiol and testosterone were inhibitory. Ovine prolactin (oPRL) also diminished the effect of T3 while ovine growth hormone (oGH) was without effect. Similar observations were observed from the in vivo studies.

      Thyroid hormone levels, especially T4, were low during premetamorphosis, increased during prometamorphosis, to peak levels during metamorphic climax, and declined in the juveniles. The changes in whole body concentrations of Cortisol paralleled the changes in thyroid hormone concentrations. On the other hand, whole body estradiol and testosterone concentrations did not show significant change and remained low throughout the larval period. The expression of GH and PRLmRNA, as assessed by in situ hybridization using cDNA for flounder PRL and GH also increased during the metamorphosis. However, the increase in the expression of GH and PRL genes was observed later than the increases in tissue levels of thyroid hormones and Cortisol. At late climax, the flounder larvae have undergone considerable transformation, presumably triggered by both hormones, hence the increase in PRL could hardly be antimetamorphic but may have other physiological implications.
    • Conference paper

      Growth and survival of milkfish (Chanos chanos) larvae reared on artificial diets 

      IG Borlongan, CL Marte & J Nocillado - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A preliminary feeding experiment was conducted to determine growth and survival of milkfish larvae reared on various feeding regimes involving the use of artificial diets. Two larval diets (Feed A and Feed B) containing 45% protein and 10% lipid were fed either alone or in combination with Brachionus from day 8 to day 21. The feed in the control treatment were Brachionus (10 ind/ml) from day 8 to day 14 and Artemia (2-3 ind/ml) from day 15 to day 21. Larvae in all treatments were fed Brachionus (10 ind/ml) from day 2 to day 7.

      No significant differences were observed in survival rates, total length, wet weight and dry weight among fish fed combination of Brachionus and Feed B and the control feed (Brachionus and Artemia). These promising results indicate the possibility of using Feed B as partial replacement or supplement to live food. However, lowest survival rates, total length, and weight were obtained in fish fed either Feed A or Feed B alone, indicating that the test artificial diets given solely to milkfish larvae starting from day 8 can not support good growth and survival. Further studies on the development of improved artificial diets for larval milkfish need to be done.
    • Conference paper

      Larviculture of milkfish (Chanos chanos) in outdoor tanks 

      MN Duray - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      In the past, larviculture of milkfish depended entirely on the use of rotifers and brine shrimp nauplii and rearing trials were done under roofed facilities. Since the dietary value of live food varies according to culture and feeding conditions, rotifers were enriched with SELCO, a lipid emulsion containing high levels of highly unsaturated fatty acids (HUFA) prior to feeding the larvae. Alternatively, a microbound larval feed (Nosan R-1) was given as a supplement to rotifers during the first two weeks of culture. Larval growth was enhanced and survival was significantly improved when rotifers were enriched or supplemented with these diets. All rearing trials were conducted in 5-10 tons concrete circular/rectangular outdoor tanks.

      Verification runs on the use of HUFA-enriched rotifers to milkfish larvae were tried in two nearby private hatcheries. Results from mis collaborative work are presented.
    • Conference paper

      Mass larval rearing technology of marine finfish in Japan 

      K Fukusho - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      With economic development and increased demand for high price fish, industrial scale marine finfish culture in Japan was started in 1960-1965 for yellowtail Seriola quinqueradiata. Sustainable supply of wild juvenile and development of floating cage with synthetic fiber net have spurred the culture of nearly 30 species and total production in 1991 is 265 x 103 metric tons (nearly 25% of total aquaculture production). Although salmon ranching had been started in 1888, a national project of ocean ranching was only initiated in 1963 with the present target of 26 species of marine finfish. Ocean ranching aims to increase fisheries resources in coastal sea by stocking hatchery-reared juveniles and preservation of environmental capacity and habitat. Therefore, mass production of marine finfish juveniles is being done for the intensive culture in net cage and for stocking coastal sea in Japan.

      Nearly 200 million juveniles are produced by ocean ranching centers (14 national, 49 prefectural, 21 city and town, 53 fishermen's association). The number of target fish is about 60 species (excluding salmon and trout). The main species produced are red sea bream, Pagrus major, flounder, Paralichthys olivaceus, puffer, Takifugu rubrapes, rockfish, Sebastes shlegeli, and mud dab, Limanda yokohamae. More than one million juveniles of these species are produced at one hatchery or ocean ranching center per one fry production season. About 70% of total production of juveniles consist of red sea bream and flounder. Red sea bream could be used to introduce mass larval rearing technology in Japan since its mass production is well developed. The focus of the present paper is the present status and short history of the development in larval rearing technology for red sea bream.
    • Conference paper

      Oral administrations of chemotherapeutics via the bioencapsulation technique: A tool for therapeutic treatment in larviculture 

      RSJ Gapasin, HJ Nelis & P Sorgeloos - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The application of the bioencapsulation technique as a tool for curative treatment in fish larvae was investigated. Antibacterials, trimethoprim (TMP) and sulphamethoxazole (SMX), incorporated in an oil emulsion (SELCO, Artemia Systems N.V., Ghent, Belgium) were bioencapsulated at different concentrations (20% and 40%) in Artemia (Instar II) nauplii. Chemotherapeutics-loaded nauplii were fed to European sea bass (Dicentrarchus labrax) larvae only once at 5 individuals/ml. Larvae were sampled after feeding at time intervals 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 12, 16, 20, 24, 36, 48, 60, 72 h. Drug concentrations in the larval tissue were analyzed by high-performance liquid chromatography (HPLC). Results indicated that larvae fed 40% "medicated"-Artemia assimilated significantly higher levels of chemotherapeutics in the tissue as compared with those fed 20% "medicated"-Artemia. Chemotherapeutics given at higher concentration (40%) reached peak levels (19.3 µg TMP/g DW, 23.32 µg SMX/g DW) in the larval tissues within 2 h while at lower concentration (20%) peak levels (8.74 µg TMP/g DW, 6.73 µg SMX/g DW) were observed within 5 h. Moreover, TMP persisted longer (>72 h) in the tissues than SMX (12-16 h) suggesting a more efficient uptake and retention of TMP and/or faster metabolism and elimination of SMX.
    • Conference paper

      A review of grouper (Epinephelus suillus) fry production research in Malaysia 

      HM Ali - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Research on grouper (Epinephelus suillus) fry production in captivity has been carried out in Malaysia since 1986 at Tanjung Demong Marine Finfish Production and Research Centre (TDMFPRC) but the breakthrough was only achieved four years later in 1990. Eggs were obtained through natural and induced spawning in tanks. Natural spawning of grouper in captivity seldom occurred and was unpredictable. However induced spawnings were successfully carried out by injecting human chorionic gonadotropin (hCG) intramuscularly at a dose of 500-1000 IU/kg fish.

      The results from several trials on larval rearing conducted since 1989 until recently showed that larvae obtained from natural spawnings survived longer with some reaching the juvenile stage. The highest recorded survival rate of 43 days posthatch (32.5 mm total length) was 12.1% at 28-32 °C water temperature. On the other hand, 100% mortality usually occurred in larvae obtained from induced spawning 7 days after hatching.

      The major constraints of grouper fry production in Malaysia are lack of male spawners, inconsistent and unpredictable natural spawning, small quantity of eggs released every spawning day, poor fertilization and hatching rate, weak hatchlings, and high mortality rate at the early stages of larval development. The latter is probably due mainly to problems on initial feeding.
    • Conference paper

      Successful use of cryopreserved oyster trocophores as a live first feed larval marine fish and invertebrates 

      BJ Harvey - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Trochophore-stage larvae of the Pacific oyster Crassostrea gigas were cryopreserved in bulk and stored in liquid nitrogen for periods up to two years before thawing and feeding to a variety of warmwater and coldwater larval marine fish, as well as to marine shrimps and other invertebrates. The commercial product ("TrochoFeed"), marketed in both pre-thawed and cryopreserved versions, has been used successfully in the early rearing of cultured species including red drum, snook, grouper, and black cod, as well as for numerous warmwater and coldwater aquarium display fish.

      This paper describes the nutritional profile of the cryopreserved trochopores and presents a summary of the available growth and mortality data.