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作 者 ：杨德国,危起伟,陈细华,刘鉴毅,朱永久,王凯

期 刊 ：生态学报 2007年 27卷 3期 页码：862~869

关键词：中华鲟；产卵；水文条件；水电站；长江；

摘 要 ：国家一级保护动物中华鲟为江海溯河产卵的洄游性鱼类，1981年即葛洲坝截流前，其产卵场分布在金沙江下游和长江上游的约600km江段。葛洲坝水电工程阻断了其产卵洄游通道，调查发现自1982年以来，中华鲟在葛洲坝下游江段的狭小范围成功产卵。对中华鲟繁殖季节葛洲坝下中华鲟产卵场的水温、流速、流量、含沙量和水位等水文数据进行了分析，并对其与中华鲟产卵的关系进行了探讨。结果表明，葛洲坝截流后，宜昌中华鲟产卵场江段10~11月份的月平均流速及11月份的月平均含沙量发生明显变化（P﹤0.001），而月平均水位、流量及水温的变化不明显。多年观察结果显示，中华鲟产卵时，5种水文因子的参数均有一定的变动范围。1983~2004年期间，37次中华鲟产卵时的日平均水温范围为16.10~20.60℃，平均为18.63℃；日平均水位范围为40.69~47.32m（黄海高程），平均为43.91m；日平均流量范围为7170~26000 m³/s，平均为13908 m³/s；1983~2000年31次中华鲟产卵时的日平均含沙量范围为0.10~1.32 kg/m3 ,平均为0.46kg/m³ ；日平均流速为0.81~1.98m/s，平均为1.30 m/s。分析得到较适宜中华鲟产卵的水温是18.0~20.0℃，流量是14100 m³/s，水位是42.0~45.0m，含沙量是0.2~0.3 kg/m³，底层流速是1.0~1.7m/s。水温是中华鲟产卵的必备条件，水温适宜的情况下，水位、流速和含沙量出现逐渐从高位下降的趋势、而且各水文要素值均达到其适宜范围时，中华鲟即产卵繁殖。三峡工程运行后，下游江段水温的变化可能会对中华鲟的性腺发育和产卵繁殖产生不利影响，而江水含沙量下降对其产卵繁殖较有利。

Abstract:

It was believed that the historical spawning grounds of the anadromous Chinese Sturgeon (Acipenser sinensis) were located along an about 600 km long river section reaching from the lower reaches of the Jinshajiang River to the upper reaches of the Yangtze Rive.

As a result of the construction of the Gezhouba Hydroelectric Dam was built in 1981, the upstream spawning migration route was blocked by the Dam. Successful natural reproduction, however, has been observed in small areas below the dam since 1982. Some biologists held that there was a certain relationship between the spawning of Chinese sturgeon (CS) and the hydrology as well as the substrate types of the river bottom. In total, spawning runs of the CS were observed 37 times between 1983 and 2004. Five hydrological factors (water temperature, water level, flow discharge, silt content and current velocity) were monitored on a daily basis at the spawning ground between October and November for 22 years (1983 to 2004). The current velocity on the spawning ground at the river bottom was measured while CS were spawning during 4 years (1996 to 1999). The authors analyzed the relationship between five hydrological factors and the respective spawning runs. The results showed that mean current velocity during October and November and the resulting mean silt content in the sediment in November in the reach of spawning ground were significant differences (P<0001) from those immediately after the construction of the Gezhouba Dam. However, monthly mean water level, flow discharge and water temperature had no obvious effects on the bottom conditions. The 22-years of observations indicate that the daily mean values of all of the 5 hydrological factors fluctuated within a certain range while CS were spawning. It is concluded that the optimal values for the hydrological factors during the spawning run are 18.0 to 20.0℃ for temperature, 14100 m³/s discharge volume, a water level of 42.0 to 45.0m above sea level, and a silt content in the water of 0.2 to 03 kg/m³ while the current speed above the bottom to stimulate the fish to spawn should be between 1.0 to 1.7m/s. The optimal water temperature might provide an essential pre-condition for the other factors becoming a valid trigger for spawning. As water temperature arrive approaches the optimal values and most of the other parameters are at the brink to deviate from their optimal range values (water level, current velocity, silt content in the water), CS would begin to spawn. By 2009, when the Yangtze Three Gorges Project, which is located 45 km upstream the Gezhouba Dam, is completed and begins to operate normally, changes in the downstream water temperature are expected and these may have a negative effect on the gonad development and the stimulation of spawning of CS, however, the anticipated decline of silt content in the water may be considered as favourable for the performance of the spawning site.

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