Title: The effect of stocking density on growth rate, survival and yield of GIFP tilapia (Oreochromis niloticus) in Cuba: case study fish fram La Juventud

An experiment was conducted to examine the effects of stocking density on growth performance and production of male GIFT tilapia (Oreochromis niloticus) in the La Juventud fish farm in Cuba. In the study three different densities D1, D2 and D3 (3, 3.2 and 3.5 fish /m² respectively) were tested three each with three replications in nine 2 hectare earthen ponds. The oxygen concentration, temperature and pH in the ponds were measured biweekly. The mean final weight was not significantly different for the D1 (386g) and D2 (389g), but the lower growth corresponded at high density D3. The net production was significantly higher at the D2 density (23390±1703 kg/ ha) than at either D1 (21104±434kg/ha) or D3 (20299±868 kg/ha) density. There was no significant difference in survival rate at different densities. The FCR was highest at the D3 (1.9±0.15) and D2 (1.7±0.02) stocking densities and significantly higher than at the D1 density (1.5±0.13). Stocking density significantly affected water quality, with significantly higher dissolved oxygen and pH at the D1 and D2 than the D3 density. Simple modeling of production costs suggested that the highest gross revenue and net profit contribution were attained at the medium density.