Standardization of stocking density for maximizing biomass production of Pangasius pangasius in pond cage aquaculture

Abstract

Aim: Pangasius pangasius, a species of freshwatershark catfish native to Mekong River is highly resistant to crowding and low oxygen therefore, can be a suitable species for cage aquaculture. The objective of the present study was to standardize the stocking density of catfish P. pangasius in pond cage aquaculture for maximizing biomass per unit water area. Methodology: A comparative study was conducted in fish cages (2.0 m×2.0 m × 1.0 m) installed in earthen pond of 600 m-2 area and depth of 2.0 m. Stocking density of P. pangasius fingerlings was maintained @ 15 m-3 (C1), 20 m-3 (C2), 25 m-3 (C3) and 30 m-3 (C4), respectively. Fish seed was procured from, Kolkata, West Bengal. The experiment was conducted for 120 days. Fish (in cages) were fed with formulated diets (30.0 % crude protein on dry weight basis) @ 3% body weight twice a day. Physico-chemical parameters of water and growth parameters were calculated. Results : Maximum biomass was produced in C3 which was 60.14 %, 22.72% and 12.21 % higher than C1, C2 and C4, respectively, with cent percent survivability in all the cages. Better feed conversion ratio was noted in C3 (1.541) as compared to C1 (1.825), C2 (1.645) and C4 (1.956), indicating higher the stocking density better feed conversion ratio up to stocking density of 25m-3, and afterwards (@ 30 m-3) food conversion efficiency decreased. The experimental fish recorded the value of exponent 'b' in the range of 2.868 to 3.063 revealing both negative, as well as positive allometric growth pattern and condition factor 'K' of all experimental fish was above 1.0 (1.344 - 1.825) indicating robustness or well-being of experimented fish. Interpretation : The appreciable growth rate exhibited byfish during rearing period indicated that the species is suitable for cage culture at higher stocking density as food fish to meet the increasing nutritional demand.