Stocking density of Nile tilapia fry during sex inversion phase
Keywords:
Cage, Hapa net, Oreochromis niloticus, Fish culture, TilapicultureAbstract
This aim of this study was to evaluate, by means of husbandry índices, Níle ti/apia fry of Taíwanese strain at different stocking densities, during the sex inversion phase. The experimental design was totally randomized with four stocking densities and three replications over a period of 30 days. Fish were stocked at 1, 3, 5 and 7 fry L-1 in hapa net cages. The fish were fed five times a day, with commercial animal feed containing 17a-methyltestosterone. The lowest densities resulted in the highest coefficients of variance for average values of weight and length. The averages of the fishes' final individual weights were inversely proportional to stocking density, with the occurrence of the quadratic effect. We concluded that fry growth rate was negatively influenced by a rise in stocking density. However, higher stocking densities show better growth homogeneity without impacting the survival and sex inversion rates.
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