钱塘江水系兰溪段鱼类资源现状

2016年3月—2017年11月,对钱塘江水系兰溪段的鱼类资源进行逐季度采样调查,对该水域鱼类种类组成、生态类型、优势种、多样性指数、群落结构、ABC曲线和捕获情况进行了分析。试验结果显示,共采集鱼类59种,隶属5目13科44属,其中,鲤科鱼类种类最多(67.8%);优势种为鲤鱼和似鳊;生态类型以中小型、杂食性、底层性鱼类为主;Margalef丰富度指数呈先增后减的趋势,2016年的Simpson多样性指数、Shannon-Wiener多样性指数和Pielou均匀度指数均呈逐渐减小的趋势,而2017年这3个指数除9月份最小外,其他月份变化差异不显著;鱼类群落结构季节变化差异显著,但处于稳定状态;鱼类资源严重小型化。

Current Status of Fishery Resources in Lanxi Section of Qiantang River Drainage

Fish species composition,ecological guilds,dominant species,diversity index,community structure,ABC curve and catch were monthly analyzed in Lanxi section of Qiantang River drainage from March 2016 to November 2017. A total of 59 species were found,belonging to 5 orders,13 families,and 44 genera,with the most species in Cyprinidae,accounting for 67.8% of the total species number,mainly small and medium-sized omnivorous bottom fish. Common carp Cyprinus carpio and Pseudobrama simoni were the dominant species,and the small,omnivorous,and benthic fishes were the primarily ecological types. Margalef′s diversity index was shown to be increased and then to be decreasesd. There was gradually decrease in Simpson diversity index,Shannon-Wiener diversity index and Pielou diversity index in 2016,without significant difference in the three indices in 2017,except for the minimum in September. Fishes community structure was varied significantly,with stable condition,and severe miniaturization of fish stocks.