Responses of spawning thermal suitability to climate change and hydropower operation for typical fishes below the Three Gorges Dam

River thermal regime is a critical factor affecting the initiation of spawning and breeding success in freshwater fish species. The four main domestic carps (FMDCs) Chinese sturgeon are representative warm-water cool-water fishes with different requirements Yangtze Basin, China. This study focused on these two types species below Three Gorges Dam (TGD), response curves were constructed. daily suitability index (TSI) was simulated based scenario analysis climate-induced water warming cooling. variation TSI-based indicators then analyzed to evaluate climate change hydropower operation. results showed that time likely be advanced by 1.3 days average for FMDCs delayed 2.1 0.2 °C increase temperature. For FMDCs, would narrow window, although it may advance has been postponded TGD operation, cooling widen window but further postpone spawning. sturgeon, aggravate negative impacts operation narrowing delaying spawning, while offset We suggest adjusting rules, e.g., elevating temperature early period expand reducing at least 1.2 during essential maintaining restoring natural process populations. Our also beneficial inferring cumulative cascading operations provides insights management conservation tolerances other hotspot regions.