乌江银盘水电站蓄水前后坝上和坝下江段的鱼类资源及其变动特征

Fish Resources and Their Variation Characteristics in the Upstream and Downstream of Yinpan Dam in Wujian River Before and After the Impoundment of the Reservoir

为了解乌江银盘水电站蓄水前后坝上和坝下江段的鱼类资源及其变动特征,于2009—2015年7—8月在乌江下游银盘水电站坝上和坝下江段开展渔获物调查。通过调查,在坝上和坝下江段共采集到鱼类100种。银盘水库蓄水后,坝上和坝下江段的鱼类种类数明显减少,种类组成发生变化,其中喜流水生境鱼类和产黏沉性卵鱼类的种类数减少较多;主要经济鱼类的种类组成及其相对丰度发生改变,并逐渐以中、小型鱼类为主;长江上游特有鱼类的种类数及其相对丰度减少明显。丰度生物量比较曲线显示,蓄水前后坝上和坝下江段的鱼类群落结构均已受到人类活动的严重干扰,且蓄水后捕捞到的鱼类个体规格相较之蓄水前更小。蓄水后坝下流水江段鱼类资源变动程度相较之库区江段要小。研究结果可为梯级水电开发背景下乌江下游鱼类资源的保护提供基础数据支撑。

In order to find the fish resources and their variation characteristics in the upstream and downstream of Yinpan Dam in the lower reaches of Wujian River before and after the impoundment of the Yinpan Reservoir,fishery catch survey was carried out from July to August in 2009—2015.The results showed that a total of 100 fish species were collected in the upstream and downstream reaches of Yinpan Dam before the impoundment.After the impoundment of Yinpan Reservoir,for the upstream and downstream reaches,the species number decreased significantly and composition of fish species altered obviously,herein the species number of fishes that prefer to the flowing water habitat,and fishes that spawn drifting eggs,decreased considerably;the species compositions and relative abundances of main economic fishes changed,and gradually dominated by the small and medium-sized fishes;the species numbers and relative abundances of endemic fishes in the upper reaches of the Yangtze River decreased obviously.Abundance biomass comparison curves showed that the fish community structure in the upstream and downstream reaches of Yinpan Dam before and after the impoundment had been seriously disturbed by human activities,and the individual sizes of fishes caught after the impoundment was smaller than those before the impoundment.The change degree of fish resource in the downstream section of Yinpan Dam after the impoundment is smaller that those in the reservoir section.The results can provide basic data for the protection of fish resources in the lower reaches of Wujiang River under the background of cascade hydropower development.