Culture of hormonal sex reversal nile tilapia in earthen pond at different stocking densities
2002
Watcharin Rattanachoo(Department of Fesheries, Bangkok (Thailand). Trang Inland Fisheries Station) | Paiboon Wattanakich(Department of Fesheries, Bangkok (Thailand). Trang Inland Fisheries Station)
Effects of stocking densities on growth, production and flesh quality of hormonal sex reversal nile tilapia reared in earthen ponds were investigated. Fish with average body weight of 1.65 gram and average body length of 3.76 centimeter were stocked at 15 and 30 fish/square m in 300 square m earthen ponds supplied with aeration by means of paddle wheel. Fish were fed with catfish pellet containing 25.35 percent protein. The results of the experiment showed that average body length and body weight of fish stocked at 15 fish/square m were significantly (p LT 0.05) higher than those of fish stocked at 30 fish/square m. The average body length, body weight and production/pond of fish stocked at 15 and 30 fish/square m were 27.93+-0.12 and 26.11+-0.99 centimeter, 440.91+-2.44 and 336.62+-0.72 gram and 1\}525.00+-49.50 and 2,183.00+-94.75 kilogram/pond respectively. Percentage of male fish were 97.50+-0.71 and 97.00+-1.41 percent and the percentage of female fish were 2.50+-0.71 and 3.00+-1.41 percent, respectively. Survival rate and food conversion rate of fish at the two stocking densities were very similar which were 76.89+-1.88 and 72.00+-2.83 percent, and 1.27+-0.02 and 1.38+-0.08, respectively. The lowest break-even price for long-term operation of two groups of fish was 21.83+-0.55 and 21.85+-1.20 baht/kilogram, respectively. Quality of fish flesh indicated by gel strength, brix and moisture levels were 594.60+-38.18 and 536.14+-44.01 g. cm, 9.97+-0.33 and 9.50+-1.20 percent brix, 80.75+-0.65 and 79.80+-0.90 percent for the fish stocked at 15 and 30 fish/square m, respectively. These values were in the range which are suitable as raw material for processing industry. The results of culture and fish size production, fish stocked at 15 fish/square m gave a better results than those stocked at 30 fish/square m.
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