Abstract:

Human activities, including reservoir construction, river diversion, embankment construction, and hydrological regulation in the upper reaches of the Yangtze River, have severely impacted fish habitats, causing environmental degradation and substantial habitat loss. To gain deeper insights into this issue, we selected habitat data over the past three years from four typical river sections at Zhutuo Station, which is in the middle part of the Yangtze River protection zone. We analyzed the hydrological features, water environment quality, flow velocity, water depth, and spatial distribution patterns of rare and endemic fish species to comprehensively characterize fish habitats. Based on the analysis results, we propose to establish comprehensive measures for the proliferation and release of rare and endemic fish species. Our research shows that 99% of the rare and endemic fishes aggregate in areas with flow velocities of 0.0-1.4 m/s, among which approximately 80% gather in slow-flow zones with velocities below 0.8 m/s. During the wintering period, the average water depth where fishes gather is 44.28 meters, with a minimum of 15 meters and a maximum of 57.47 meters. When the absolute water depth in the upper reaches of the Yangtze River ranges from 23 to 56 meters, it fails to provide suitable fish habitats. However, during the water-storage period, raising the water level can improve the living conditions of rare and endemic fish species while meeting requirements for flow velocity, water depth, and minimal interference. Studying the habitat characteristics of rare and endemic fish resources in the upper reaches of the Yangtze River enables us to better understand fish distribution and migration patterns, facilitating the rational planning and management of fishery resources. Simultaneously, researching proliferation measures can guide management actions such as artificial release, aiding in the restoration and enhancement of fish populations and ensuring the sustainable development of fisheries.

Key words: upper reaches of the Yangtze River, rare and endemic fishes, habitat characteristics, fish habitat, proliferation pathway