2023年三峡水库生态调度对四大家鱼生境面积的影响

Effect of Ecological Operation of Three Gorges Reservoir on Spawning HabitatArea of the Four Major Chinese Carps

为量化生态调度对四大家鱼生境面积的影响,2023年在三峡水库开展了针对葛洲坝下游四大家鱼自然繁殖的生态调度试验,以葛洲坝至枝江江段为研究区域,选择水位变幅、水深、流速、水温4个主要生境因子,建立了耦合平面二维水动力学模型和产卵栖息地适宜度曲线的四大家鱼产卵生境质量评估模型,实现了产卵综合适宜度指数时空分布的精细化模拟。结果显示,2023年三峡水库生态调度期间,约60%研究区域四大家鱼产卵综合适宜度指数呈现增加趋势,其产卵加权可利用面积占研究区域总面积比例由30.45%增加至约55%;适宜四大家鱼产卵区域(综合适宜度指数0.6~1.0)明显增加,占研究区域总面积比例由4.67%增加至约60%。研究表明,三峡水库生态调度显著改善了葛洲坝至枝江江段四大家鱼产卵的生境质量。

Ecological operation of hydropower facilities is necessary to protect fishery resources and the effect of the ecological operation can be evaluated by monitoring the scale of spawning hab⁃itat for target fish species.From May 27 to June 3,2023,an ecological operation experiment at Three Gorges Reservoir(TGR)was carried out,aiming to increase natural reproduction of the four major Chinese carps downstream of Gezhouba Dam,a run-of-the river dam below TGR at Yichang.In this study,a section of the Yangtze River from Gezhouba Dam to Zhijiang was investi⁃gated.The impact of ecological regulation on the spawning habitat area of the four major Chinese carps was estimated based on model simulations.The quality assessment model for spawning habitat was established by coupling a two-dimensional hydrodynamic model to the spawning habitat suit⁃ability index(HSI)curve.Four major habitat factors(water level amplitude,water depth,flow rate,and water temperature)were selected as model parameters.The spatial and temporal distribution of the comprehensive spawning HSI was simulated and the change in suitable spawning habitat area was analyzed.Results show that during ecological operation in 2023,the comprehensive spawning habitat suitability index increased by 60%in the study section,and the proportion of suitable spawn⁃ing habitat area(weighted available area)increased from 30.45%to 55%.The areas suitable for spawning for the four major Chinese carps,with a comprehensive spawning habitat suitability index ranging from 0.6 to 1.0,have significantly increased from 4.67%to 60%of the total study area.In conclusion,the ecological regulation of Three Gorges Reservoir in 2023 significantly improved the quality of spawning habitat for the four major Chinese carps from Gezhouba dam to Zhijiang.