Larviculture of milkfish (Chanos chanos) in outdoor tanks
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Abstract
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.
Suggested Citation
Duray, M. N. (1996).Larviculture of milkfish (Chanos chanos) in outdoor tanks. In C. L. Marte, G. F. Quinitio, & A. C. 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 (pp. 150-158). Tigbauan, Iloilo, Philippines: Aquaculture Department, Southeast Asian Fisheries Development Center.
Type
Conference paperISBN
9718511326Related items
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Research on marine and freshwater fishes
(Aquaculture Department, Southeast Asian Fisheries Development Center, 1995)Most of the fish research at SEAFDEC AQD in 1992-1994 was on milkfish. Studies were conducted on year-round spawning through hormonal or environmental manipulation; optimum lipid and protein levels and ration size for captive broodstock; and the influence of spawner age on reproductive performance. The economics of hatchery operations, alone or integrated with broodstock as a commercial enterprise, was assessed. Mass production of larvae was refined with the use of commercial or SEAFDEC-formulated larval diets. Alternative rearing schemes in large tanks and ponds were tried. Hatcheryproduced and wild-caught larvae were compared in terms of growth and production in experimental nursery and grow-out ponds. Supplemental diets for brackishwater grow-out culture were formulated. Studies on broodstock management of grouper Epinephelus spp. included lipid enrichment of the diet and hormonal induction of sex inversion. Seed production techniques were developed but survival rates were low. Grouper culture was found economically feasible in experimental ponds with 'trash' fish as feed. The mangrove red snapper Lutjanus argentimaculatus was successfully induced to spawn with injection of human chorionic gonadotropin. Initial larval rearing trials were successful but survival rates must be improved. Hormonal manipulation of spawning of the Asian sea bass Lates calcarifer allows seed production during most of the year. Photoperiod manipulation leads to maturation of females, but not males, beyond the natural breeding season (April-November). Nursery rearing of 9 mm juveniles is feasible in floating net cages with night lights that attract food zooplankton. The requirements of sea bass for lipid, protein, carbohydrates, and essential amino acids were determined. In the rabbitfish Siganus guttatus, weekly injections of luteinizing hormone releasing hormone analogue (LHRHa) sustains milt production for three weeks. Thyroid hormones injected into broodstocks improved the growth of larvae to day 7. Induced spawning techniques for the Asian catfish Clarias macrocephalus were refined by determining the seasonal responsiveness to LHRHa and pimozide injections and testing for pheromonal induction of spontaneous spawning. The optimum insemination rate was determined and egg hatchability was enhanced by removal of the adhesive coat before incubation. Several practical diets for catfish during grow-out culture were tested against 'trash' fish. The broodstock management for bighead carp Aristichthys nobilis was studied. Cage-reared juveniles from cage-reared broodstock showed the best growth. To improve the reproductive performance, the broodstock diets were supplemented with vitamins A, C, and E. Research on tilapias focused on genetics and strain selection. Several strain testing procedures for Nile tilapia were evaluated in their efficiency to detect economically important strain differences. Reference lines were developed from two existing red tilapia strains to measure and reduce the effects of uncontrolled nongenetic variables in strain evaluation experiments with Nile tilapia. The tolerance of two Nile tilapia strains to heavy metals was similar when gauged by the 24-hour and 96-hour lethal concentration and by fish growth, survival, and reproductive performance. In a separate study, four strains of red tilapia showed generally higher seed production when reared in tanks than in cages. Improvements in the feed and feeding management for Nile tilapia were also studied. Intensive tilapia farming and feeding have led to oxygen depletion and fish kills in Sampaloc Lake. To rehabilitate the lake, it is imperative to reduce the farming area from 30 to 6 hectares; stop the use of commercial feeds; and remove the water hyacinths and other debris. Fish kills in Laguna de Bay have also become serious in recent years, and a review of the occurrences, losses, and possible causes is currently being conducted. Studies on the epizootic ulcerative syndrome of snakeheads in Laguna de Bay have yet to pinpoint the pathogen. Skin lesions in tilapias in several ponds and lakes in the country were found to be due to bacteria. -
Studies on breeding and seed production of the new species of fish with high commercial value
(Japan International Research Center for Agricultural Sciences, 2001)Aquaculture contributes significantly to food production and provides the means to generate increased revenue for countries in Southeast Asia. As the catch from the capture fisheries stagnate and population growth rate in the region continue to be among the highest in the world, the requirement for cheap sources of protein is expected to come from increased production of low trophic level species such as milkfish (Chanos chanos) and tilapia (Oreochromis spp.). There is also an increasing demand for high value fish species such as groupers and snappers particularly for the live food fish markets of affluent and developing countries in Asia. In order to meet the demand for more food fish and to develop new products for the export market, the most important component of any culture system must be met - that of adequate supply of fry and juveniles for culture Fry availability has been a major constraint in the development of culture systems for new species and in further increasing production of established culture species. The SEAFDEC Aquaculture Department is addressing the problem of fry availability through its research on breeding and seed production of several marine species. To date, commercially viable technologies for breeding and. seed production of milkfish, sea bass (Lates calcarifer) and rabbitfish (Siganus guttatus) have been developed and continue to be refined. Captive breeding and experimental hatchery production of grouper (Epinephelus coiodes) and the mangrove snapper (Lutjanus argentimaculatus) have also been achieved. Another major focus of SEAFDEC AQD’s research is the development of breeding and seed production technologies of endangered marine species such as the sea horse (Hipocampus spp.) and other marine ornamental fish. The Philippines and other Southeast Asian countries are the major suppliers of marine ornamental fish for the aquarium trade and for medicinal use. These fish species are caught from coral reefs and seagrass beds using destructive fishing techniques such as cyanide fishing that has resulted in the destruction of vast areas of the marine coastal environment. Captive breeding of these endangered species will pave the way for future restocking and conservation programs to ensure their survival. This paper provides an overview of research accomplishments in marine fish breeding and seed production, current activities, and future directions for research at SEAFDEC AQD. -
The Philippine aquaculture industry
(Aquaculture Department, Southeast Asian Fisheries Development Center, 1988)The aquaculture sector of the Philippine fishing industry registered the highest growth rate of 12.5% in 1977-1986. The contribution of aquaculture to the total fish production was equivalent to 24% in 1986 compared to only 85 in the early 1970's. In terms of quantity, the mariculture subsector registered the highest growth rate of 10.2% in 1982-1986, whereas in terms of value the brackishwater fishpond subsector showed the highest growth rate of 33%. Meanwhile, freshwater aquaculture production exhibited a negative growth rate due to reduction of activities in Laguna de Bay and the slow expansion in hectarage of the commercial freshwater fishponds. Research by several agencies concentrated heavily on the culture of milkfish (Chanos chanos), tilapia (Oreochromis niloticus), Chinese carps (Aristichthys nobilis and Hypophthalmichthys molitrix), tiger prawn (Penaeus monodon), and sea bass (Lates calcarifer). Innovations in seaweed, oyster, and mussel farming are also discussed. Research directions are presented to assure an ecologically sustainable growth in aquaculture with emphasis on countryside development.
