The effect of the river embankment on the natural reproduction of Chinese sturgeon

摘要

The number of Chinese sturgeon in the Yangtze river had sharply decreased after its migration path was cutoff by the Gezhouba dam. In order to improve the navigation in the downstream area of the Gezhouba dam, a river embankment was built again in the spawning site of Chinese sturgeon in December of 2004. This embankment changed the environment of Chinese sturgeon's upstream spawning site, and could lead to some severe effects on Chinese sturgeon. This paper presents a new method used to evaluate the effect of Gezhouba river embankment to Chinese sturgeon. The method coupled a three-dimensional hydrodynamic model and a habitat suitability model to simulate the spawning ground suitability of Chinese sturgeon. The simulated result shows that the construction of the river embankment has strongly affected the spawning ground of Chinese sturgeon. The upper spawning ground almost disappeared and the suitability of the lower spawning ground decreased. The position of spawning ground offsets to the right bank of the Yangtze river. In addition, the impact of the river embankment on spawning ground varies with different operating conditions of the Gezhouba dam, thus a better ecological operation could be found and used to relieve the negative effects on the natural reproduction of Chinese sturgeon.