岷江下游干流段鱼类资源现状及其多样性分析

2014~2016年在岷江下游干流开展了4次鱼类资源调查，共采集到鱼类71种（亚种），隶属于3目11科51属，其中包括长江上游特有鱼类16种。不同调查江段鱼类组成相似性指数分析结果显示，宜宾和乐山江段相似性指数最低，70%；宜宾和屏山江段相似性指数最高，9219%。岷江下游干流江段主要经济鱼类为鲤（Cyprinus carpio）、光泽黄颡鱼（Pelteobaggrus nitidus）和瓦氏黄颡鱼（Pelteobagrus vachelli），在岷江下游整个江段渔获物中各占1610%、1396%和1232%。对调查到的71种鱼类产卵类型进行分析结果显示，产粘性卵鱼类和漂流性卵鱼类分别占渔获物总重量的6828%和2707%。不同调查时间和不同江段多样性指数存在差异，其中5~7月份调查到的鱼类多样性指数高于10~12月份调查结果；乐山和犍为江段间鱼类均匀度Pielou指数存在显著差异（P<005）。从调查结果看，岷江下游干流段鱼类种类丰富，渔获物数量较高，但受岷江下游梯级开发的影响，资源前景不容乐观，需加强保护措施。

Analysis of Fish Resources Status and Diversity in the Lower Reaches of the Minjiang River

Fish resources of lower mainstream of the Minjiang River were investigated four times between 2014 and 2016.A total of 71 fish species (and subspecies) were identified inside 3 orders,11 families,and 51 genera,in which 16 species are endemic species of the upper Yangtze River.The similarity index analysis of fish composition from different river sections showed that the similarity between Yinbin and Leshan reaches was the lowest (70.00％),whereas Yibin and Pinshan sections had the highest similarity index (92.19％).The main economic fish species in the studied river sections included Cyprinus carpio、Pelteobaggrus nitidus and Pelteobagrus vachelli,and their percentages inside all captures were 16.10％,13.96％ and 12.32％ respectively.The 71 species fishes spawning type analysis showed the fish that producing sticky eggs and drifting eggs accounted 68.28％ and 27.07％ of the total weight of captures,respectively.Fish diversity index between may and July were obviously higher than that between October and December.The fish Pielou indexes of Leshan and Qianwei sections showed significantly difference (p ＜ 0.05).Overall,our field investigations showed the lower mainstream of Minjiang River had high fish species richness and biomass,but the fishes resources may not be optimistic in the future due to several hydraulic power plants constructions,fishery resource protection should be strengthened soon.