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Abstract

Two experiments were conducted co evaluate the use of small tanks as a hatchery for the production of tilapia fry and fingerlings. The effect of stocking density of brood fish on fry production was evaluated using a sex ratio of four females to one male. Brood fish (Tilapia aurea) were stocked at rates of 2.7, 5.4 and 8.1 Fish/m2 in nylon spawning nets (hapas) suspended in tanks. Fry were collected seven times at 2-week intervals. Mean fry production was 12.2, 15.1 and 23.8/m2/hapa/day or 5.3, 3.9 and 3.8/female/day, respectively. The fry were stocked at races of 26, 52, 78, 104, 130 and 155/m2 to determine the optimum rate for fingerling production. The fry were fed four times daily for 63 days. The daily feeding rate was 15% of initial body weight for three weeks followed by weekly adjustments to 5%. Predation by dragonfly larvae caused wide variation in survival (23-88%). Fry at the 26/m2 rate grew fastest, averaging 2.3 g with 37% survival. 13.5% actual feeding rate and 2.3 feed conversion ratio. Fry at the 104/m2 rate weighed 1.2 g with 88% survival, 6% actual feeding rate and 0.75 feed conversion ratio. The data indicates that the daily feeding rate should be higher than 5% of body weight for maximum growth but should not exceed 40 kg/ha/day in small static tanks.

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