丹江口水利枢纽兴建后汉江中下游四大家鱼等早期资源及其演变

The early evolution of the four major Chinese carps resources in the middle and lower reaches of Hanjiang River after the construction and operation of Danjiangkou Reservoir

2006～2007年对汉江中下游四大家鱼早期资源进行了调查,并结合1977～1978年、2004年汉江中下游的历史调查资料进行分析。研究表明:汉江中下游四大家鱼卵苗径流量下降明显,从20世纪70年代末的近5×108粒(尾)下降到2004年以后的不足1×108粒(尾),四大家鱼卵苗径流量占鱼类卵苗总径流量的比例也从19.0%下降到了1%以下;产卵场数量减少了1处,产卵场位置也发生了变化。

Surveys on reproduction of the four famous Chinese carp were conducted at the middle and lower reaches of Hanjiang River during spawning season from 2006 to 2007. The result shows the current egg production is less than 1×10^8 ind, which had been almost 5 ×10^8 ind. at the end of 1970s; the proportion of the famous Chinese carps is descending 19.0% to 1% of the tatal runoff. According to the calculation of the spawning sites, one of them is eliminated now because of the construction of the Danjiangkou Reservoir, and the location of the others are changed when comparing to the historical data.