Management of fish health in broodstock and larvae of milkfish, sea bass and grouper
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Historically, reports on the occurrence of disease problems in milkfish, seabass and grouper were mainly on the isolation and identification of etiological agents. Studies on the tolereance of fish to chemotherapeutants were also conducted. Various species of vibrios and gill-infesting parasites have been associated with diseases in all life stages of these fish. Presently, mortalities due to diseases of unknown etiology, environmental failure and nutritional or husbandry shortfalls affect successful fry production in the hatchery. Morphological deformities in hatchery-produced milkfish fry is a major problem to be solved. In seabass fry production, swim-bladder stress syndrome occasionally occurs and results in mass mortalities. In larval grouper culture, the problem of low survival is being addressed through improved husbandry and nutrition. For cage-held broodstock that naturally spawn in captivity, such as milkfish and grouper, the main problem is fouling of net enclosures in the cages. However, for fish that need hormonal manipulation to spawn, such as seabass and snapper, stressful handling procedures during sampling and hormone injection may lead to injuries and scale loss. The damaged areas become focal points for secondary bacterial infection. Future fish health management strategies in these fish should incorporate a holistic approach to include environmental monitoring, nutritional manipulation, immunostimulants and vaccine use, and biological control in addition to pathogen exclusion in the rearing system and the fish.
Emata, A. C., Lavilla-Pitogo, C. R., Duray, M. N., & Toledo, J. D. (1996). Management of fish health in broodstock and larvae of milkfish, sea bass and grouper. In K. L. Main & C. Rosenfeld (Eds.), Aquaculture health management strategies for marine fishes?: proceedings of a workshop in Honolulu, Hawaii, October 9- 13, 1995 (pp. 47-56). Walmanalo, Hawaii: The Oceanic Institute.
PublisherThe Oceanic Institute
- Conference Proceedings 
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Larval and early juvenile development of silver therapon, Leiopotherapon plumbeus (Actinopterygii: Perciformes: Terapontidae), reared in mesocosms FA Aya, MNC Corpuz, MA Laron & LMB Garcia -
Acta Ichthyologica et Piscatoria, 2017 - Szczecińskie Towarzystwo NaukoweThe silver therapon, Leiopotherapon plumbeus (Kner, 1864), is an endemic and economically important freshwater food fish in the Philippines. The natural populations of this species have been declining during the past years, mainly due to intense fishing pressure, habitat degradation, and introduction of invasive alien species. At present, it is considered a target species for domestication and conservation efforts. Despite several attempts of artificial reproduction and larval rearing, little is known on larval and early juvenile development of silver therapon. The presently reported study was therefore intended to fill this gap in the knowledge by determining the growth and describing body proportions, pigmentation, and fin formation of this fish. Newly hatched larvae were reared in mesocosm tanks at a mean temperature of 29.5°C. Larvae up to 30 days after hatching were sampled at irregular intervals and preserved in 5% buffered formalin. Early development stages for 245 preserved specimens were described in detail with reference to changes in morphology, growth and body proportions, pigmentation, and fin formation. Five developmental stages of silver therapon were identified: yolk sac larva (1.88 mm TL), preflexion (2.51 mm TL), notochord flexion (4.50-8.27 mm TL), postflexion larva (6.90-12.21 mm TL), and early juvenile (>13.40 mm TL). Growth was isometric for eye diameter and gape size whereas positive allometry was observed for body depth, head length, and preanal length. Some body proportions showed abrupt changes from preflexion to postflexion larvae before it stabilized during the early juvenile stage. Pigmentation in the form of stellate and punctate melanophores increased with developmental stage, with larvae becoming heavily pigmented from postflexion to early juvenile stage. These morphological changes, together with the full complement of fin rays and squamation observed in specimens larger than 13.4 mm TL, suggest the attainment of the juvenile stage of this species. These morphological changes may explain the food and feeding habits during the early life stages of silver therapon which is critical to their survival and recruitment in the wild and in a mesocosm hatchery environment.
Conference paperK 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 - Aquaculture Department, Southeast Asian Fisheries Development CenterAquaculture 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 paperMZ Muhammad - In CT Villegas, MT Castaños & RB Lacierda (Eds.), Proceedings of the Aquaculture Workshop for SEAFDEC/AQD Training Alumni, 8-11 September 1992, Iloilo, Philippines, 1993 - Aquaculture Department, Southeast Asian Fisheries Development CenterAquaculture especially brackishwater fish culture in Malaysia has a very high potential for development. It is also a very important source of protein. The three major species cultured in cages are sea bass, grouper, and snapper. They are very popular, especially sea bass which is a highly esteemed delicacy. Sea bass culture started in the mid-1970. The fry was obtained from the wild or imported from Thailand or Singapore. This industry developed slowly because of inadequate supply of seed. During this period also, the culturist had very little experience in managing the cages. As an answer to the problems of the industry, the Fisheries Research Institute (FRI) of the Department of Fisheries, Ministry of Agriculture, Glugor, Penang, established a unit responsible for research on hatchery propagation, larval feed development, and cage culture of sea bass. The Brackishwater Unit of FRI situated in Gelang Patah, Johor is responsible for research and development of sea bass grow-out in coastal ponds. The Marine Finfish Production and Research Centre (MFPRC) situated in Tanjung Demong, Terengganu was set up in 1982 for marine fish fry mass production. The Extension Branch of the Department of Fisheries in Kuala Lumpur is responsible for all extension services, including promotion of sea bass aquaculture as well as other species. The Extension Branch also operates the MFPRC and organizes training on coastal aquaculture at the Brackishwater Aquaculture Centre in Johor. The Fisheries Development Authority of Malaysia (LKIM), a government statutory body formed in 1971 with the objectives of upgrading the socioeconomic status of fishermen and developing the fisheries industry, is also involved in marine fish culture, especially in setting up commercial culture projects involving local fishermen. In addition to government bodies, some universities in Malaysia also carry out activities related to marine fish culture, especially disease studies.