Author(s): Yuhong Zeng; Yunge Li
Linked Author(s): Yuhong Zeng
Keywords: Ecological water level habitat suitability lake-resident fish East Dongting Lake
Abstract: Dongting Lake is the second largest freshwater lake in China, an important flood regulating and storing area in the Yangtze River basin, and its ecological value is significantly high. Affected by the operation of the Three Gorges Reservoir and the inflow of four rivers (e. g., Xiang, Zi, Yuan and Li river), the water level of the East Dongting Lake fluctuates seasonally, which has an obvious effect on the spawning habitat of lake-resident fish like common carp and crucian carp. A 2D hydraulic hydrodynamic model of the East Dongting Lake has been constructed using the Mike 21, and then the fish habitat suitability assessment was conducted based on hydrodynamic characteristics of East Dongting Lake in 2018. The impact of water level fluctuations on the suitability of spawning habitats was quantified, and two ideal ecological water level ranges of 22.74–23.90 m and 25.18–26.98 m for East Dongting Lake were suggested. Then the hydrological data from 2000 to 2020 was analyzed, and the habitat quality for lake-resident fish in East Dongting Lake was assessed from 2000 to 2020. The result shows that the fish spawning habitats were of lower quality in 2007 and 2011, which has been validated by the collected survey data of the spawning site in East Dongting Lake. Further correlation analysis showed that both the mean water level and the daily rise rate of water level have significant impact on the spawning area of lake-resident fish. The proposed quantitative relationship between fish habitat suitability and water level can provide crucial guiding to the conservation of fishery resources in the Dongting Lake.
Year: 2025