Evaluating the effectiveness of fingerling stocking and ecological perspectives in enhancing fish harvest in a large tropical reservoir of Northern India

Abstract

The present study evaluated the effectiveness of stocking the Gangetic carps, viz. Labeo catla, Labeo rohita, and Cirrhinus mrigala, in a large tropical reservoir, Uttar Pradesh, India. Time series data of 22 years (1998 to 2019) on fingerling stocking and fish harvest were collected from the State Department of Fisheries, Govt of Uttar Pradesh. The average annual stocking was 36 nos.ha−1 yr−1, and the fingerling stocking size was ranged between 10 and 90 mm total length (TL) with a mean of 30 mm TL. The average fish production potential of the reservoir was estimated at 77.15 kg ha−1 yr−1. The analysis revealed that fish yield from the reservoir progressively increased from 75.02 t to 297.39 t with a mean of 148.82 ± 69.45 t. The regression analysis between the stocking density and yield of stocked species showed an insignificant relation in the reservoir (R2 = 0.0873, p = 0.2495). The percentage change in the production of stocked species in comparison with the previous year was found to be negative for 12 years between 1998 and 2019 indicated an unstable trend. The finding indicated that low stocking density, very small size at stocking, the low conversion efficiency of the photosynthetic energy to fish (0.016%), and the dominance of catfishes were the major causes for the low fish productivity. We suggest greater stocking density of 500 fingerlings ha− 1 yr−1, stocking of fingerlings (> 100 mm TL), in situ breeding and rearing in cages and pens, adoption of cage culture technology, and identification and conservation of the breeding ground of the Gangetic carps to optimize the management regime in utilizing the production potential of reservoirs vis-a-vis ensuring livelihood security and sustainability of the fishers. Keywords Gangetic carp · Stocking · Rihand reservoir · Production potentialNot Available