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No Thumbnail AvailableProjectPreliminary studies on the effects of three animal manures on the ecological conditions of pond water and fish growth
Establishment of a Network of Aquaculture Centres in Asia
1983Also available in:
No results found.The use of organic manure in aquaculture is one of the main inputs in the Chinese system of integrated fish farming. Although many scientists in China and elsewhere have done much work on the effects of animal manure on aquaculture production (Chen Qiyu et al, 1982, Buck, 1978. 1979; Schroeder 1978, 1980; McGeacin et al, 1982; Stickney, 1977; Jhingran et al, 1980; Edwards, 1980; Zweig, 1981), little is known of the series of physical, chemical and biological processes which are taking place in a pond after application of manure. The complexity of energy recycling needs further studies. The aim of this study is to determine the independent contribution of three animal manures to changes in the ecological condition of pond water and fish production. The results to be obtained may provide the scientific basis for further research on the use of organic manure in fish culture. -
No Thumbnail AvailableProjectWater quality conditions as disease related stressors in Clarias pond culture
Programme for the Development of Pond Management Techniques and Disease Control
1981Also available in:
No results found.Quality characteristics of water in two Clarias culture ponds were monitored through a grow-out cycle then assessed as stressors relating to disease and mortality. The two ponds were part of a small-scale commercial fish farm growing Clarias and Ophicephalus. The culture system was representative of the Clarias practice in Thailand where distressed fish and relatively high mortalities are typical. The two Clarias ponds, about 1,000 m2 each, were stocked with 0.6 g. fingerlings at the rate of 7 7 and 78/m2 on March 1, 1980. The fish were fed a mixture of ground trash fish and rice bran (9:1) then harvested after 5 months giving yields of 3,931 (3.73 kg/m2) and 5,088 kg (5.3 kg/m2) from pond No. 1 and pond No, 2, respectively. Correspondingly, average weights of harvested fish were 122 and 144 g, food conversion ratios were 6.4 and 4.9, and survival rates were 40.3 and 47.4%. Two incidences of relatively high mortalities were observed at the same time in each pond; the first occurred 49 to 53 days after stocking and the second was during the period 120 to 150 days after stocking. Pathological examination of the distressed and dead fish revealed that they were highly infested with Aeromonas sp. bacteria. Water conditions in the ponds were characterized by low Secchi disc transparency (av. 9 and 10 cm. through the grow-out period), very little DO (av. late afternoon values over the last 3 months of 0.8 and 1.3 mg/1), generally high CO2 values (in excess of 20 mg/1 through abou t 60 days of the cycle), high BOD (av2. 8.5 and 8.8 g O2/m3/day), and high un-ionized ammonia (2.2 and 3.0 mg/1, av. through the first 60 days). -
No Thumbnail AvailableProjectEffects of different animal manures on the ecological factors and fish yield in fish ponds
Network of Aquaculture Centres in Asia
1988Also available in:
No results found.Different animal manures were used in the experiment. Fish yield of the chicken-manured pond was the highest, followed by that of the duck-manured pond, the pig-manured pond and the cow-manured pond. The factors which affected the fish yield were the inorganic nitrogen, phosphorus, and the biomass of zooplankton and phytoplankton.
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