Partial replacement of slow growing mrigal with common carp and amur carp: Its impact on fish yield and economics in composite fish culture system

An experiment was conducted in Mid-Central Table Land zone of Odisha to assess different stocking ratios of fish with partial replacement of slow growing mrigal by common carp and amur carp in composite fish culture system. In this experiment, five different treatments including farmers’ practice was taken with four replications. The different stocking ratio taken with / without substitution of mrigal were: catla : rohu : mrigal = 3:4:3 (T1), catla : rohu : mrigal : common carp = 3:4:1.5:1.5 (T2), catla : rohu: mrigal : amur carp = 3:4:1.5:1.5 (T3), catla : rohu : mrigal : common carp = 3:4:2:1 (T4) and catla : rohu : mrigal : amur carp = 3:4:2:1 (T5). Out of the five treatments, maximum yield, FCR, Net return, Net Present Value, BC ratio, Internal Rate of Return and minimum payback period was observed in case of T3 followed by T2. Minimum yield, FCR, Net return, Net Present Value, BC ratio, Internal Rate of Return and maximum payback period was found in case of T1. Replacement of mrigal by common carp or amur carp showed more yield. Replacement by amur carp showed better result than that by common carp. Also 50% replacement showed better result than 33%.