葛洲坝下游江段中华鲟产卵场食卵鱼类资源量估算

为定量评估食卵鱼类对中华鲟资源的危害，1997－2001年间，对中华鲟产卵场所在的葛洲坝水利枢纽坝址至下游庙嘴之间长约5km的江段，进行了渔业捕捞样本抽样和解剖检测，运用体长股分析方法并结合淦获物中不同种类的相对数量比例估算出食卵鱼类资源量，研究结果表明，吞食中华鲟卵的主要有圆口铜鱼，铜鱼，瓦氏黄颡鱼等11种鱼类，其年度资源量为197487－744487尾，多年平均444822尾。

ESTIMATION ON ABUNDANCE OF BENTHONIC FISHES PREYING ON EGGS OF CHINESE STURGEON IN REACH BELOW THE GEZHOUBA DAM IN THE YANGTZE RIVER

From 1997 to 2001, assessment on the annual abundance of benthonic fishes which prey on eggs of Chinese sturgeon were undertaken through commercial fisheries surveys in the reach below the Gezhouba Dam where the spawning ground of Chinese sturgeon located in the Yangtze River. Eleven species of benthonic fishes were confirmed to be egg predators through the examination of gut contents. The dominant species of egg predatory fishes were Coreius guichenoti, C. heterodon and Pelteobagrus vachelli. First of all, by applying Jones Length based cohort analysis, annual abundance of C. heterodon was estimated with fishing data collected in springs and autumns. Then, abundance of the rest egg predatory fishes were counted according to the quantitative ratios of them to C.heterodon in catches. Summarily, annual abundance of egg predatory fishes fluctuated from 197 487 to 744 487 with an average of 444 822 individuals within the research period. Due to assemblage for preying on eggs, abundances of egg predatory fishes were obviously higher in course of egg deposition of Chinese sturgeon, and numbered from 335 005 to 2 064 607 with an average of 486 750 individuals annually. It was estimated also that approximately 2 565 172 eggs, corresponding to the fecundity of 4 females, were eaten by egg predatory fishes daily in the egg deposition periods of Chinese sturgeon.