Growth and production of endangered Indian butter catfish,Ompok bimaculatus(Bloch) at different stocking densities in earthen ponds

Abstract

Growth, survival and production of endangered Indian butter catfish (Ompok bimaculatus) fingerlings were examined at different stocking densities. The experiment was conducted for 8 months in nine earthen ponds having an area of 0.03 ha each. 30-day-old fingerling, stocked at 40 000 ha−1 was designated as treatment-1 (T1), 50 000 ha−1 as treatment-2 (T2) and 60 000 ha−1 as treatment-3 (T3). At stocking, all fingerlings were of same age group with a mean length and weight of 3.36 ± 0.08 cm and weight of 0.83 ± 0.02 g respectively. Fish in all the treatments were fed with a mixture of rice bran (50%), mustard oil cake (30%), fish meal (19%) and vitamin-mineral premix (1%). Physicochemical parameters, plankton populations and soil parameters were at the optimum level for fish culture. Highest weight gain was observed in T1 and lowest in T3. Final length, weight and survival of fish also followed the same trend as weight gain. Highest specific growth rate was observed in T1 followed by T2 and T3. Feed conversion ratio was significantly lower in T1 followed by T2 and T3 in that order. Significantly higher amount of fish was produced in T1 than T2 and T3 respectively. Higher net benefit was obtained from T1 than from T2 and T3. Overall, the highest growth, survival and benefit of fish were obtained at a density of 40 000 fingerlings ha−1. Hence, of the three stocking densities, 40 000 fingerlings ha−1 appears to be the most suitable stocking density for culturing of Indian butter catfish in grow-out system.