Experimental study on ecological operation of Three Gorges Reservoir to promote natural reproduction of four major Chinese craps (PPT)

摘要

The four major Chinese craps (FMCC) which spawn mainly from May to July are typical species of complex ecosystem in the middle Yangtze River. The hydraulic conditions necessary for natural reproduction of FMCC have been changed because of the cascade reservoirs operation in the upper reaches of Yangtze River. In order to study the effect of ecological operation of Three Gorges Reservoir(TGR) on natural reproduction of FMCC, ecological operation experiments have been carried out seven times from 2011 to 2015 and the hydrodynamic conditions required for the natural reproduction of FMCC were artificially created by controlling the discharge of TGR. According to the monitoring results of water temperature, hydrodynamic characteristics and spawning amount in Yichang and Shashi sections during the ecological operation period, the dynamic response relationship between natural reproduction of FMCC and ecological operation was analyzed. The results showed that there is a significant correlation between the reproduction of FMCC and the ecological operation of TGR. The daily increase of river flow and the continuous time of water rising are the key indexes affecting the reproduction of FMCC if the water temperature and spawning ground are suitable. The results can provide important technical basis for optimization of ecological operation during normal operation period of TGR.