Standardization of stocking density on genetically improved farmed tilapia (GIFT) Oreochromis niloticus in pond cage aquaculture system

Aim: To standardize the stocking density of GIFT strain of Nile tilapia (Oreochromis niloticus) to optimize survival, growth, biomass production and maximum economic gain in pond cage culture system. Methodology: Study was conducted in triplicate for 180 days in fish cages installed in cemented pond of 726 m(-2) area and depth of 2.0 m. Stocking density of GIFT Tilapia was maintained @ 40 m(-3) (C1), 50 m(-3) (C2), 60 m(-3) (C3), 70 m(-3) (C4), 80 m(-3) (C5) and 90 m(-3) (C6), respectively. Water quality and growth parameters were studied at fortnight basis. Supplementary diet (D-1) (30.0 % crude protein on dry weight basis) was provided @ 2% body weight. Survival rate, average growth rate, biomass production, specific growth rate (SGR), feed conversion ratio (FCR), length-weight relationship, condition factor, economics and benefit cost ratio were evaluated. Results: All water quality parameters were within the limit suggested for aquaculture. Maximum survival was achieved in C1 (96.25%) and survival rate reduced with increasing stocking density in cages. Decrease in SGR was observed with increasing stocking density. The average growth rate was highest in C1 (112.20 g) and lowest in C6 (61.80 g) whereas the maximum biomass (23.136 kg) was harvested from C4 with stocking density of 70 m(-3) with best FCR (1.32). Benefit cost ratio was evaluated best in C4 (0.39). Interpretation: Pondcage aquaculture with improved stockingcondition is suitable for GIFT tilapia growth,biomass production and maximum economic gain.