长江中游监利江段鱼类早期资源及生态调度对鱼类繁殖的影响

为了解三峡水库开展试验性生态调度后长江中游监利江段鱼类早期资源现状，本研究于2018年、2019年的5—7月对该江段卵苗种类组成、资源量、产卵场及生态水文指标开展了调查，共鉴定出鱼类7目14科54种（属），其中产漂流性卵鱼类26种。仔鱼组成以贝氏䱗（）（占15.2%）、沙鳅属（粒、324.2×10⁸尾；2019年分别为35.9×10⁸粒、1140.7×10⁸尾。监利江段成为鳊（）等鱼类的重要产卵场。生态调度对监利江段贝氏䱗、鳊、银鮈等鱼类的自然繁殖有明显促进作用。产卵量与涨水持续时间、流量累积涨幅呈正相关。监利江段涨水持续时间4 d及以上，流量累积涨幅3500 m³/s及以上时，产卵量可占当年调查期间鱼卵总规模的8.4%以上。建议继续开展并优化生态调度，加强对监利江段鱼类早期资源的基础研究。

The early-stage fish resources and effects of ecological regulation on fish reproduction at the Jianli section of the Yangtze River

An investigation into the status of early-stage fish resources was carried out at the Jianli section, in the middle reaches of the Yangtze River, from May to July in 2018 and 2019. The survey focused on the changes in species composition of fish eggs and larvae, the amount of eggs and larvae, spawning site, and the ecological hydrology index following the experimental ecological operation of the Three Gorges Reservoir. About 49 species of fish eggs and larvae belonging to 14 families and 7 orders were identified, and among these fish, there were 26 species spawning drifting eggs. (44.9% of the total count) was shown to have an absolute advantage in the species composition of larvae, followed by sp. (12.5%). In 2018, it was estimated that the total runoff of fish eggs and larvae were 33.3×10⁸ ind and 324.2×10⁸ ind, respectively. In 2019, there were 35.9×10⁸ ind and 1140.7×10⁸ ind, respectively. The Jianli section has become an important spawning ground for , and other fish. Ecological regulation played an obvious role in promoting the natural reproduction of at the Jianli section. There was a positive correlation between the quantity of fish eggs and the time of flow increase, and a positive correlation between the quantity of fish eggs and the flow increase. When the duration of flow increase is four or more days, and the flow increase is 3500 m³/s or more, the spawning quantity could account for more than 8.4% of the annual survey total. We suggest continuing and optimizing the ecological flow scheduling to strengthen basic research on early-stage fish resources at the Jianli section.