Author(s): Three Gorges Dam Regulation Scheme; Li Chong; Liao Wengen; Chen Daqing; Xu Tainbao; Liu Shaoping; Liu Jianhu
Linked Author(s):
Keywords: Chinese carp; Spawn; Hydrodynamic effects; Fish habitat modeling; TGD regulation scheme
Abstract: The four major species of Chinese carp (FCC), black carp (Mylopharyngodon piceus), grass carp (Ctenopharyngodon idellus), silver carp (Hypophthalmichthys molitrix) and big head (Aristichthys mobilis), are main fishes in the Yangtze River. Based on a fishery survey in 1986, there are 11 spawning sites located in the upper Yangtze River from Chongqing City to Sandouping where Three Gorges Dam (TGD) is at. Because of the major intervention of TGD construction and operation, hydrodynamic conditions within the impounded zone were altered, which accordingly will cause spawning and aquatic habitat change. In this research, a total of 622 cross sections in the Yangtze River and hydrology data from 1997-2003 were used. Also by extracting two supposed processes from TGD regulation scheme in Sandouping, three scenarios were simulated by using DHI software MIKE 11 in upper Yangtze River from Zhutuo gauge station to Sandouping. According to growth period of spawn or fry captured at Yunyang gauge station in 2002~2003, four spawning sites from Zhutuo gauge station to Yunyang gauge station were ascertained based on the hydrodynamic results, which is congruous with previous research. Based on previous experiments, safe floating time and distance from spawn to swimming fry were studied for the FCC. The results show that when TGD regulation scheme with 156m water level is carried, hydraulic characters at three of four spawning sites do not suit for spawning of the FCC. For the forth spawning site in Chongqing city, though there is no alternation in hydraulic processes, if rising flow in May is less than 8000 m3/s, there would be still not enough floating time and distance for the growth of spawn. If TGD regulation scheme with 175m water level is carried, there would be neither enough floating time nor distance for growth of spawn before the middle of June at the four spawning sites. After the middle of June, hydraulic processes’ effects on the forth spawning site in Chongqing city are negligible for both two TGD regulation schemes, and the floating time and distance are good for growth of spawn.
Year: 2007