胶州湾近岸浅水区鱼类群落结构及多样性

根据2009年3月-2010年2月在胶州湾西北部近岸浅水区进行的鱼类逐月定置网调查数据,采用生态多样性指数和多元统计分析等方法研究了该海域的鱼类群落结构及多样性特征.结果表明:调查共鉴定出44种鱼类,其中海洋性27种,河口性鱼类17种.鱼类种类组成与底层水温和盐度有密切关系.胶州湾近岸浅水区鱼类群落Margalef种类丰富度指数(R)变化范围为0.33-3.50,Shannon-Wiener多样性指数(H’)为0.42-2.25,Pielou均匀度指数(J’)为0.23-0.93.聚类分析(CLUSTER)和多维标度排序(MDS)分析表明,不同鱼类种类组成的各月份样品可划分为3个组分:水温较低的冬季组G1(12月-翌年4月)、水温次高的春秋季组G2(5-6月、10-11月)和水温最高的夏季组G3(7-9月).其中G1的典型种主要为尖海龙(Syngnathus acus)、方氏云鳚(Enedrias fangi)和玉筋鱼(Ammodytes personatus)等冷温性常栖类群种类,G2的主要典型种为鳀鱼(Engraulis japonicus)和尖海龙,G3的主要典型种为鲐鱼(Scomber japonicus)、细条天竺鱼(Apogonichthys lineatus)和普氏缰虾虎鱼(Amoya pflaumi)等洄游性鱼类.单因子相似性分析(ANOSIM)表明,3个月份组间鱼类群落结构差异显著,不同月份组间两两差异均显著.生物-环境分析(BIOENV)表明,底层水温是影响胶州湾近岸浅水区鱼类群落结构时间变化的主要环境因子.在胶州湾内近岸浅水区发现40余种幼鱼,但占优势的主要为低值鱼类,表明胶州湾的产卵、肥育场功能有所下降,应加强胶州湾近岸水域生态环境和渔业资源的保护及修复.

Community structure and species diversity of fish assemblage in the coastal waters of Jiaozhou Bay

Jiaozhou Bay, which locates in the south of Shandong Peninsula, is a semi-closed natural bay extending from the Yellow Sea. It serves as an excellent spawning and feeding ground for fishes and other invertebrate animals, and is an important ecosystem with high productivity and biodiversity. However, due to the high fishing pressure, pollution, coastal development and the effect of global warming, major changes have taken place in the region. Based on the data collected monthly in the set net survey from March 2009 to February 2010 in Jiaozhou Bay, fish community structure and species diversity were examined by ecological diversity indices and multivariate statistical analysis. The results showed that there were 44 species of fishes (young of the year) in the survey, of which 27 species were marine fish, and the rest 17 species were estuarine fish. The fish species composition of Jiaozhou Bay was closely related with the bottom water temperature and salinity. The Margalef species richness index (R) of fish species composition in Jiaozhou Bay ranged between 0.33 and 3.50, and the Shannon-Wiener diversity index (H') were from 0.42 to 2.25, with the Pielou evenness index (J') varying from 0.23 to 0.93. According to the hierarchical cluster analysis (CLUSTER) and non-metric multi-dimensional scaling (MDS) analysis, fish samples were classified into three month-groups, which are group 1(G1, December-April) with the lowest bottom water temperature, Group 2(G2, May-June, October-November) with higher water temperature and Group 3(G3 July-September) with the highest water temperature. The typifying species in G1 were some resident cold temperate fish species such as great pipefish Syngnathus acus, blenny Enedrias fangi, sand eel Ammodytes personatus; Japanese anchovy Engraulis japonicus and great pipefish Syngnathus acus were main typifying species in G2, Pacific chub mackerel Scomber japonicus, cardinal fish Apogonichthys lineatus, Amoya pflaumi and other migrate fish species were typifying species in G3. The analysis of similarities (ANOSIM) indicated that there were significant differences in species compositions among the three month-groups. The biota-environment matching (BIOENV) analysis showed that bottom water temperature was the main environmental factor that determined the temporal pattern of fish assemblage in Jiaozhou Bay. About 40 larval and juvenile fish species were found in Jiaozhou Bay, but they are mainly low-valued fish species. The results indicated that the capacity as a spawning and nursery ground has declined in Jiaozhou Bay. Some measures should be taken to conserve and restore the ecological environment and fishery resources in the region.