天然河道中鱼类对水深、流速选择特性的初步观测——以长江江口至涴市段为例

将长江江口至涴市天然河道的鱼类水声学调查数据和水文学观测数据相结合，在对流速和水深空间插值基础上，提取不同鱼类规格和密度对应水深和流速的特征值，从而研究鱼类对天然河道中水层平均流速、水深2个环境因子的选择特性。研究结果表明：①不同规格的鱼对流速和水深的选择存在差异，规格小的鱼选择了较低的流速和较宽的流速范围，规格大的鱼选择了较高的流速和较窄的流速范围；规格小的鱼选择的水深明显高于规格大的鱼，喜好的水深范围也宽于规格大的鱼。②鱼类密度对流速的选择性不明显，但对水深的选择性明显，即深水区鱼类密度较高。③研究江段范围内江口镇附近江心洲两侧流速变幅范围较其上、下游江段宽，并且江心洲两侧鱼类的分布密度也高于其邻近上、下游段鱼类密度。可见，江心洲的存在提供了流速多样性格局，丰富了鱼类生境的多样性。本研究方法可为评价河流栖息地适宜性及生态功能提供借鉴。

Preliminary Observation on Preference of Fish in Natural Channel to Water Velocity and Depth:Case Study in Reach of Yangtze River from Jiangkou Town to Yuanshi Town

 On the basis of the hydrology observed data and hydro-acoustically surveyed data in the reach of Yangtze River from Jiangkou Town to Yuanshi Town, the preference of the fish in the natural channel to the water velocity and depth is analyzed by the method of interpolation in air space of water depth and velocity corresponding to the fish density and fish size. The results show as follows: Different sized fishes have different preferences to the water velocity and depth. Smaller fishes prefer lower velocities and wider range of velocity, while larger fishes prefer higher relocities and narrower range of velocity. The depths smaller fishes enjoy are higher than those larger ones do; the range of the depths smaller fishes enjoy is more than that larger ones do. The fish density is not directly related to the water velocity, but to the depth, fish density is higher in the deeper water. The distribution features of the water velocity and fish density are different around the island in the reach of Jiangkou Town, which shows due to the diversity existence of velocity near the island may supply more suitable environments for fish. This preliminary study could provide some references to the assessment of the habitat suitability and ecology function of a river