观音岩水电站蓄水前后金沙江攀枝花江段鱼类群落结构及变化特征

基于2013~2017年金沙江干流攀枝花江段的鱼类资源监测数据，分析了观音岩水电站蓄水前后该江段的鱼类群落结构特征及变化情况。5年共监测到鱼类65种，长江上游特有鱼类共20种，5年均监测到的鱼类有12种，其中11种为喜流水性鱼类。各年度鱼类多样性指数呈现一定波动。ABC曲线及W统计表明2013和2014年鱼类群落结构未受到扰动，但在观音岩水电站蓄水运行后受到严重干扰。CA和NMDS分析显示鱼类群落可以分为两组，组I包括2013和2014年，组II包括2015、2016和2017年，one-way ANOSIM显示这2组在统计学上没有显著性差异。对聚类结果进行SIMPER分析结果显示，在观音岩水电站运行后，产漂流性卵的鱼类丰度明显降低，如圆口铜鱼、长鳍吻鮈等。因此，为了更好地保护攀枝花段的鱼类资源，应采取包括就地或迁地保护、生态调度和人工繁殖放流的针对性措施。

Changes of Fish Community Structures in Panzhihua Section of the Jinsha River Before and After Impoundment of the Guanyinyan Hydropower Station

Based on fisheries resources surveys conducted in the Panzhihua section of the Jinsha River from 2013 to 2017, variation characteristics of fish biodiversity before and after impoundment of the Guanyinyan Hydropower Station were statistically analyzed in present study. A total of 65 fish species belonging to 3 orders and 10 families were identified during the five-year study period, 20 of which were endemic to the upper reaches of the Yangtze River. Of the 65 fish species, 12 were detected in each year, all of which were lotic fishes except Pseudobagrus vachelli. Abundance/biomass comparison (ABC) curves and W statistics revealed that fish communities were seriously affected after impoundment and operation of Guanyinyan Hydropower Station in October 2014. Cluster analysis (CA) and non-metric multidimensional scaling analysis (NMDS) showed that fish species composition could be divided into two groups: Group I (2013-2014) and Group II (2015-2017), but one-way analysis of similarity (one-way ANOSIM) indicated no significant difference between the two groups. According to similarity percentage (SIMPER) analysis, species that decreased in abundance in group II were mainly those spawning drifting eggs such as Coreius guichenoti and Rhinogobio ventralis. Therefore, to better conserve natural fish resources in the Panzhihua section, a comprehensive strategy including on-site conservation, off-site preservation, ecological operation, artificial reproduction and releasing should be developed.