The aim of this study was to investigate the impact of different stocking populations of tilapia nilotica fish in their aquaculture on some maintenance behavior, performance, economic values and hormonal concentration levels. On this research, 300 tilapia nilotica fish were distributed into different densities (15, 20,25 and30 fish per aquaria 40*30*80cm) 3 replica for each population and distributed in 70 Litter water in aquaria. 30 fish kept as aspare. After 2 weeks from the start of the experiment and at the end of the experimental periods, blood samples were collected for serum cortisol and growth hormones assay. From the obtained results we found that, The feeding and foraging behavior time and frequency (94.00+3.55 & 144.00+9.79) were improved with stocking density (15 fish in aquaria) and the aggressive behavior was at high level with overcrowding. (26.80+1.83 & 105.00+4.68), on the other hand the surfacing, swimming and resting time were increased with higher stocking rate. The growth hormone was increased with decreased stocking density. The stress indicating hormone (cortisol) was increased with high stocking populations. The return and profit were significantly increase with decreased stocking density.
Key words: Tilapia Nilotica fish, Welfare, behavior, performance stocking density, profitability, economic indices
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