雷州湾附近海域鱼类群落结构及其与环境因子的关系

Fish community structure and its relationship with environmental factors in Leizhou Bay

为了解雷州湾及其附近海域渔业生物的群落结构及其物理影响因素,于2016—2017年开展了4个季度的底拖网渔业资源与生态环境调查。运用聚类分析、相似性百分比分析以及冗余分析研究了该海域鱼类群落结构及其与环境因子之间的关系。结果表明,雷州湾附近海域共捕获鱼类256种,以底层鱼类和暖水性鱼类为主;各季节均可划分为两个亚群落(Anosim test:R=0.28～0.77, P<0.01),群落Ⅰ的平均相似性为38.48%～47.44%,相似性的主要贡献种为斑头舌鳎(Cynoglossus puncticeps)、中华海鲇(Tachysurus sinensis)和线纹鳗鲇(Plotosus lineatus)等;群落Ⅱ的平均相似性为41.38%～52.59%,主要贡献种为多齿蛇鲻(Saurida tumbil)、斑头舌鳎和花斑蛇鲻(Saurida undosquamis)等。两个亚群落的平均相异性为57.74%～76.25%;水深是4个季度显著影响鱼类分布的重要生态因子,溶解氧是3个季度显著影响鱼类分布的重要环境因子。综上所述,雷州湾及其附近海域鱼类种类数丰富,高于海州湾、大亚湾等海域;本研究揭示了该海域鱼类群落结构特征及其与环境因子的关系,为该海域鱼类资源的养护及利用提供参考依据。

Leizhou Bay, located on the eastern side of Leizhou Peninsula in Guangdong province, is the primary habitat of Chinese white dolphin(Sousa chinensis), besides being a reserve for juvenile fish and shrimp. However, the ecological state of this coastal ecosystem remains largely unknown. To understand the fish community structure and its physical drivers in Leizhou Bay, seasonal bottom trawl along with environment monitoring surveys were conducted from 2016 to 2017. The relationships of fish community structure with environmental factors were analyzed using K-means cluster analysis, similarity percentage analysis, and redundancy analysis. These analyses led to the identification of 256 fish species, comprising mainly demersal fish and warm-water fish. The study sites for each season could be divided into two groups: group I, with water depth of less than 10 m, and group II, with water depth between 10 m and 20 m. Group I showed an average similarity of 38.48%–47.44% across seasons in terms of fish community structure(which was shown as matrixes of sites by species biomass). Three species, Cynoglossus puncticeps, Tachysurus sinensis, and Plotosus lineatus contributed greatly to the average similarity within Group I in summer, fall and winter. Furthermore, Group II showed an average similarity of 41.38%–52.59% across seasons. The Saurida tumbil contributed mostly to the average similarity within Group II in spring, summer and winter. The average dissimilarity between group I and group II in seasons was 57.74%–76.25%. Six ecological factors, i.e. depth, dissolved oxygen, water temperature, salinity, pH, and chlorophyll a, explained 41.76%–47.11% of variation in fish biomass, with depth being the dominant environmental factor affecting fish community structure in each season. Moreover, the fish species richness in Leizhou Bay was obviously higher than in other bays of China. This study provides preliminary data on fish community structure and its relationship with environmental factors in Leizhou Bay, and provides clues for stocking enhancement in the waters.