长江近口段近岸段鱼类群落多样性现状

Species diversity of fish in the section near the Yangtze River estuary

摘要:

为掌握长江近口段近岸段鱼类群落多样性现状，2017年在南通和常熟江段近岸水域开展了鱼类周年调查，统计分析了鱼类群落主要参数及时空特征。结果显示，本次调查共采集到鱼类62种，隶属于8目17科。就鱼类食性、洄游习性及栖息水层等3个生态类型归类，该鱼类群落的优势类群依次为杂食性鱼类、淡水定居性鱼类及底层鱼类。渔获规格上以小于50 g的小型鱼类占优势，物种数及渔获尾数占比分别为37种、67.77%。Margalef丰富度指数（D）、Shannon-Wiener多样性指数（H'）、Simpson单纯度指数（C）和Pielou均匀度指数（E）的变化幅度分别为3.73~6.26、2.44~2.98、0.07~0.15和0.64~0.76，均值为5.03、2.62、0.12、0.73，群落多样性水平时间特征表现为春夏季高于秋冬季，空间特征则表现为常熟采样点高于南通采样点。长江近口段近岸段渔获尾数同样呈现出季节性差异，夏季的渔获尾数最多，冬季最少。聚类分析结果表明鱼类群落在相似度为44.34%时被划分为2个类群，该江段鱼类群落差异更多地来自季节变化。研究结果补充了长江近口段近岸段鱼类的基础数据，为该江段乃至长江流域渔业资源评估和保护提供了科学依据。

Abstract:

In order to understand the fish community structure and diversity in the section near the Yangtse River estuary, the temporal and spatial characteristics of fish community structure, dominant species, quantity and biomass were investigated in 2017. The results showed that 62 species of fishes were collected, belonging to 8 orders 17 families. In terms of the ecological types, omnivore fish, sedentary fish and demersal fish were dominant. In terms of fish catching specifications, small-sized fishes (<50 g) were dominant in quantity and species (67.77% and 37), and quantity of fishes with average mass less than 50 g was 59.68% and 37.59%.Analysis of the diversity index showed that: the range of Margalef index(D) was 3.73 to 6.26, Shannon-Wiener index(H') was 2.44 to 2.98, Simpson index(C) was 0.07 to 0.15 and Pielou index(E) was 0.64 to 0.76, and the average value of them was 5.03,2.62,0.12 and 0.73. As a whole, the community diversity index in spring and summer was higher than that in autumn and winter; the community diversity index in Changshu sampling site was higher than that in Nantong sampling site. Significant seasonal variations showed that fish quantity was highest in summer and lowest in winter. The clustering results showed that the fish community was divided into 2 groups when the similarity was 44.34%. Community differences are mainly due to the seasonal variation. The research supplemented the basic data of fish and provided a scientific basis for the assessment and protection of fishery resources in Yangtze River basin.