Effectiveness of carp seed stocking in large reservoir ecosystems of India

Tropical reservoir ecosystems cover more than 3.51 million ha in India which are the major sources of fish production from inland open waters and supports rich diversity of fish. The present study quantifies fisheries enhancement and evaluates the impact of stocking of Indian major carp fingerlings in six large reservoir ecosystems of India. Analysis of time series data revealed a significant increase (p < 0.05) in fish yield from 12.3 kg ha⁻¹ year⁻¹ in 2004–2005 to 52.4 kg ha⁻¹ year⁻¹ in 2016–2017 due to stocking. The average fish yield of these six reservoirs was estimated to be higher than the national average of 33 kg ha⁻¹ year⁻¹ recorded for large Indian reservoirs. Fingerling stocking had a significant positive impact on fish yield (r = 0.238, p = 0.035). The reservoir water storage level was positively correlated (r = 0.621, p < 0.05) to fish production. The study also shows that the reservoir habitat support 99 finfish species in the central Indian reservoirs of which two species belong to endangered category warranting conservation efforts. This study is the first of its kind on assessing the impact of stocking in large number of tropical reservoirs including the largest reservoir in the country revealing positive effect on fish yield. The fish yield of 85.8 kg ha⁻¹ year⁻¹ obtained in Gandhisagar reservoir (72,300 ha), India revealed that fisheries enhancement is effective and remunerative. The study also highlights the global status of stocking impact in large reservoirs and deliberates issues and suggests management strategies for sustainable fisheries enhancement in large tropical reservoirs.