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Sex-reversed all-male Nile tilapia (Oreochromis niloticus) fry (mean weight 0.15 g) were stocked at six densities (12, 25, 50, 100, 200 and 400 fish.m-2) in hapas (2 x 3 x 1.2 m) placed in a 400 m2 earthen pond. Fish were fed with mixed-feed containing 32.9% crude protein and 9.5% crude fat. After six weeks, mean weights were 29.32±0.17, 19.05±0.07, 14.80±0.57, 10.20±0.14, 5.80±0.57 and 4.65±0.35 g, respectively. Specific growth rates were 12.44±0.79, 11.43±0.69, 10.80±0.85, 9.87±0.95, 8.41±1.18 and 7.83±1.24%.day-1, respectively. The negative relationship between stocking density and specific growth rate was expressed as SGR = 15.887-1.354lnD (r2 = 0.9870, p = 0.00). Low feed conversion ratios were achieved at low stocking densities (12 to 50 fish.m-2) and increased at the high stocking densities of 200 and 400 fish.m-2. The highest condition factor was found at the lowest stocking density (12 fish.m-2) and lowest condition factor was found with the high stocking densities of 200 and 400 fish.m-2. The highest coefficient of weight variance was also achieved at 200 and 400 fish.m-2, while less size variation was found with stocking between 12 and 100 fish.m-2. The stocking density of 100 fish.m-2 was apparently an optimum density for nursing all-male Nile tilapia fry in hapas. This density also resulted in the highest standing crop of Nile tilapia fingerlings in hapas at 1.01 kg.m-2.
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