胶州湾海域鱼类群落种类组成及多样性

为了解胶州湾海域鱼类群落结构特征,根据2016—2017年间对胶州湾海域进行的4个航次底拖网调查数据,采用相对重要性指数、生态多样性指数和典范对应分析(canonical correspondence analysis,CCA)、非线性多维标度排序(non-metric multidimensional scaling,NMDS)等方法分析了胶州湾海域鱼类群落的种类组成和多样性特征。结果表明:调查共采集到鱼类46种,隶属2纲10目30科41属,以硬骨鱼纲鱼类为主(45种,97.83%)。其中,鲈形目(Perciformes)最多(22种,47.83%),其次是鲉形目(Scorpaeniformes),占15.22%。种类数季节变化明显,以夏季最高,23种;秋季最低,16种。优势种组成以赤鼻棱鳀(Thryssa kammalensis)、褐菖鲉(Sebastiscus marmoratus)、褐牙鲆(Paralichthys olivaceus)、大泷六线鱼(Hexagrammos otakii)、许氏平鮋(Sebastes schlegeli)和矛尾鰕虎鱼(Chaeturichthys stigmatias)等鱼类为主。多样性分析显示,鱼类物种多样性存在明显的季节差异。多样性指数(H′)季节变化范围为1.668—2.453,以夏季最高,春季最低;均匀度指数(J′)季节变化范围为0.577—0.808,以秋季最高,春季最低;丰富度指数(D′)季节变化范围为2.431—3.123,以冬季最高,秋季最低。典范对应分析表明,水温、盐度、水深和pH是影响胶州湾海域鱼类群落物种组成的主要环境因子,且水温和pH是影响鱼类群落结构及多样性时空变化的主要因子。与历史调查资料相比,由于人类活动对胶州湾生态系统的干扰,鱼类群落结构发生了较大变化,优势种组成更替明显,多样性水平降低,鱼类群落结构趋向简单化。

Species composition and diversity of fish community in Jiaozhou Bay

Jiaozhou Bay is a temperate semi-closed bay in the Yellow Sea, located in the Shandong Province, along the northern coast of China. In order to understand the characteristics of fish community structure in Jiaozhou Bay, data from four bottom trawl surveys (2016-2017) were used to analyze the variations in fish species composition and species diversity of fish communities by using the means of relative importance index, ecological diversity indices, canonical correspondence analysis, and non-metric multidimensional scaling. The results showed that a total of 46 fish species were captured, which belonged to 2 classes, 14 orders, 53 families, and 84 genera. Among them, Osteichthyes fishes with 45 species were the dominant one, accounting for 97.83% of the total fishes. Of these, the Perciformes fishes were the most dominant group, in which 22 species in 19 genera and 13 families were observed, which accounted for 47.83%, and followed by the Scorpaeniformes fishes with 7 species in 7 genera and 6 families, accounting for 15.22%. The seasonal variations in the number of fish species were obvious, with the highest being in summer with 23 species and the lowest in autumn with 16 species. The fishes in Jiaozhou Bay belonged to temperate fauna, which was dominated by the warm temperate fishes (47.83%), and followed by warm water fishes (30.43%). Cold temperate fishes, which were the least abundant one (21.74%). The predominant species of fish communities included Thryssa kammalensis, Sebastiscus marmoratus, Paralichthys olivaceus, Hexagrammos otakii, Sebastes schlegelii, and Chaeturichthys stigmatias. The diversity analysis showed that there were significant seasonal variations in fish species diversity. The values of Shannon-Wiener diversity index (H'') ranged from 1.668 to 2.453 with an average of 2.031, the highest was in summer and the lowest in spring. The values of Pielou evenness index (J'') ranged from 0.577 to 0.808 with an average of 0.687, with the highest value reorded in autumn and the lowest in spring. The values of Margalef richness index (D'') ranged from 2.431 to 3.123 with an average of 2.824, the highest was in winter and the lowest in autumn. The Canonical Correspondence Analysis (CCA) revealed that pH, dissolved oxygen (DO), water temperature, and water depth were the most important environmental factors affecting the species composition of fish communities in Jiaozhou Bay. Water temperature and pH were the main factors affecting both spatial and temporal changes in fish community structure and diversity. Compared with the historical survey data, the community structure of fish had changed greatly due to disturbances from anthropogenic activities in Jiaozhou Bay ecosystem. These changes included changes in the species diversity level with a reduction in the number of species, and a significant change in the composition of the dominant species, suggesting that a simplification of fish community structure has resulted in this bay.