Author(s): Jiangping Tao; Xiang Wang; Ye Qiao; Jianbo Chang
Linked Author(s):
Keywords: Changzhou fishway; Pearl River; Water level regulation; Passage effectiveness
Abstract: The Changzhou fishway (CFW) on the Pearl River is the largest fishway in China. Tao et al. (2013) studied the passage ability and fish behavior in the CFW under the flood control levels. However, studies have yet to be conducted on the passage effectiveness of the CFW under various operating modes to optimize and manage the fishway. In the present study, the effectiveness was monitored for two regulated water levels, i. e., a flood control level and the normal pool level to determine the passage effectiveness of the CFW. A total of 28 fish species were collected in the fishway basins at both water levels. These species shared a proportion of 34. 57% of the total species downstream of the Changzhou Dam on the Pearl River. Specifically, 18 fish species were collected at flood control levels, with Spualiobarbus curriculu, Pelteobaggrus vachelli, and Cirrhinus molitorella as the dominant species. At normal pool levels, 22 fish species were collected, with P. vachelli, Hemicculter leuciclus, and Pseudolaubuca sinensis as the dominant species. Fish lengths at normal pool levels were significantly greater than those at flood control levels (P < 0. 05). The number of fish ascending through the fishway at normal pool levels was also significantly higher than that at flood control levels (P < 0. 05). Results showed significantly different passage effectiveness of the fishway at both water levels. Fish communities, fish length, and the number of ascending fish varied significantly with the change of water level. The pelagic species were conditioned to use the CFW at normal pool levels, whereas the demersal species were conditioned to use the CFW at flood control levels. This alteration was attributed to changes in velocity gradients in the CFW that resulted from changes in the water level.
Year: 2013