Hydrodynamic Characteristics of Chinese Sturgeon Spawning Ground in Yangtze River*

Since the construction of the Gezhouba Dam on the Yangtze River in 1981, it has been found that the Chinese Sturgeon, Acipensor sinensis, performs natural propagation annually in a narrow reach downstream close to the Gezhouba Dam site. This might allow one to better investigate the river hydrodynamic conditions of the Chinese Sturgeon spawning ground. In this article, spatial Kinetic Energy Gradient (KEG) and absolute value of vorticity were computed along the river sections from measured data. The relation between Spawn Density per Unit Area (SDUA) and vorticity strength and between SDUA and KEG were worked out. The Results showed that the vorticity and KEG were both effective parameters for describing the hydrodynamic characteristics of Chinese Sturgeon spawning ground. The Chinese Sturgeons prefer to spawn in the river sections where the value of vorticity strength is larger than 0.4 s−1 and KEG is larger than 0.029 Jkg−1m−1.