Environmental cues for natural reproduction of the Chinese sturgeon, Acipenser sinensis Gray, 1835, in the Yangtze River, China

Abstract

For effective conservation, it is important to explore the environmental cues initiating the spawning activities of a fish species. Based on monitoring data gathered between 1998 and 2011, the relationships between spawning activities of the Chinese sturgeon, Acipenser sinensis, and several environmental cues were analyzed using the rare events logistic regression Relogit' method, which indicated that water temperature, 1-day -discharge, and atmospheric pressure were among the key spawning cues for A.sinensis (P<0.05). It is suggested that Chinese sturgeon might have an optimal environment window of 17-20 degrees C water temperature, high day-to-day discharge increase, and low atmospheric pressure for spawning. In support of Chinese sturgeon reproduction, suggested modifications to the operational procedures for the Three Gorges Reservoir (TGR) to trigger spawning are: lowering the downstream water temperature to below 20 degrees C before mid-October and expanding the period with water temperatures of between 17 and 20 degrees C; to create a day-to-day intermittent increase in the discharge to an optimal spawning water temperature; and to regulate flow at nights with a low atmospheric pressure.