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.

中文翻译：

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在印度北部一个大型热带水库中评估鱼种放养和生态观点在提高鱼类产量方面的有效性

本研究评估了放养恒河鲤鱼的有效性，即。Labeo catla、Labeo rohita 和 Cirrhinus mrigala，位于印度北方邦的一个大型热带水库中。从北方邦政府渔业部收集了 22 年（1998 年至 2019 年）鱼种放养和鱼类收获的时间序列数据。年平均放养量为 36 nos.ha−1 yr−1，鱼种放养规格在 10 到 90 毫米总长度 (TL) 之间，平均 30 毫米 TL。水库的平均鱼类生产潜力估计为 77.15 kg ha-1 yr-1。分析表明，水库的鱼类产量从 75.02 吨逐渐增加到 297.39 吨，平均为 148.82 ± 69.45 吨。放养密度与放养品种产量之间的回归分析表明，在水库中的关系不显着（R2 = 0.0873，p = 0.2495）。1998 年至 2019 年间，放养物种产量与上一年相比的百分比变化为负，12 年表明趋势不稳定。研究结果表明，放养密度低、放养时体型非常小、光合能对鱼类的转化效率低（0.016%）以及鲶鱼占优势是导致鱼类生产力低下的主要原因。我们建议增加 500 条鱼种的放养密度 ha−1 yr−1，放养鱼种（> 100 mm TL），在网箱和网栏中进行原位繁殖和饲养，采用网箱养殖技术，