Standardizing Pen Culture of Small Indigenous Fish Labeo bata in the Tropical Floodplain Wetland of the North Eastern Region, India: A Step towards Sustainable Fisheries Management

Abstract

Labeo bata fry were reared in high-density polyethylene (HDPE) pens at different stocking densities to determine growth, survival, feed utilization efficiency and economics in Borkona beel, Barpeta, Assam. Pens (500 m2 each) were stocked with fry at four stocking densities, 3 (SD3), 5 (SD5), 7 (SD7) and 9 (SD9) no. m−2 in triplicates. Feeding was performed twice a day at a rate of 3–5% body weight with floating pelleted feed containing 28% crude protein. Fish grew from 2.38 ± 0.30 g to 82.78 ± 3.18, 75.94 ± 0.89, 71.94 ± 0.89 and 61.81 ± 3.35 g at stocking densities of 3, 5, 7 and 9 no. m−2, respectively. Weight gain per cent ranged from 2491.85 ± 140.56 to 3371.33 ± 133.16 and specific growth rate from 1.41 ± 0.02 to 1.55 ± 0.02, both of which decreased with increasing stocking density. The net and gross yields increased with increasing stocking density and were highest at SD9. The benefit-cost ratio was maximum at SD7 (1.42), followed by SD9 (1.41). Post-pen culture, the monthly income of fishers increased by 6.10% (SD3) to 40.50% (SD9). Significant differences (p > 0.05) in water quality parameters were not observed between treatments (inside pens) and reference site (outside pen at 10 m distance). Weight gain exhibited a significant positive correlation with temperature (r = 0.92; p = 0.029) and alkalinity (r = 0.95; p = 0.014). The present study can provide impetus towards species diversification in pen enclosures, income enhancement of small-scale wetland fishers and sustainable ecosystem-based floodplain wetland fisheries management.