EFFECT OF DIFFERENT STOCKING DENSITIES ON THE GROWTH PERFORMANCE, SURVIVABILITY AND LENGTH-WEIGHT RELATIONSHIP OF JUVENILE CHOCOLATE MAHSEER, NEOLISSOCHILUS HEXAGONOLEPIS (McClelland, 1839)

Abstract

This study examined the effect of different stocking densities on the growth performance, survivability, and length-weight relationship of juvenile Chocolate mahseer (Neolissochilus hexagonolepis). Three 74m³ concrete tank (10m × 4.9m × 1.5m) were assigned to treatments: T1(1 juvenile/m³; n = 74), T2 (2 juvenile/m³; n = 148), and T3 (3 juvenile/m³; n = 222) in a completely randomized design. Juveniles were fed twice daily at 2% of their total biomass. The body weight and body lengths were measured at day 0 and after every 30 days for 90 days. Likewise, pH, dissolved oxygen_, and temperature of the water were recorded twice daily for all treatments. Survivability reached 100% across treatments.  The overall mean percentage weight gain was significantly higher in T1 (26.02 ± 4.52 %) and T2 (26.02±4.99 %) compared to T3 (8.34±1.29 %) (p >.05). The overall mean percentage length gain was significantly higher in T1(12.71±2.17%) followed by T2 (6.49±1.34%) (p < 0.05). Likewise, specific growth rate (%/day) was significantly higher in T1 (0.20±0.04 %) and T2 (0.14±0.04 %) compared to T3 (0.07±0.01 %) (p < 0.05). Overall feed conversion ratio was significantly lower in T1 (6.47) and T2 (6.81) compared to T3 (29.26) (p < 0.05). The juveniles showed different degrees of negative allometry. The allometric form of the length-weight relationship equation was established as W = e^−1.62 × L^2.01 for T1, W = e^−3.81 × L^2.74 for T2, and W = e^0.28 × L^1.40 for T3. Observed water quality parameters did not differ significantly among treatments (p > 0.05). A cross-sectional cost-benefit analysis showed T1 had a better economic benefit than T2 and T3. The study recommends T1 as the optimal stocking density for better growth performance, feed conversion, and economic return.