广西银滩南部海域海洋牧场鱼类群落结构特征及其与环境因子的关系

Characteristics of fish community structure and its relationship with environmental factors in marine ranching zone in southern area of Yintan in Guangxi

适时评价国家级海洋牧场示范区的鱼类资源状况,对推进海洋牧场建设具有重要意义。基于2022年4月广西银滩南部海域海洋牧场渔业资源调查数据,分析了鱼类资源特征、群落结构及其与环境因子的相关性,以为北部湾海洋牧场生态效应研究提供参考。结果显示,示范区鱼类数量密度、生物量密度和种类数均高于对照区。示范区和对照区鱼类物种组成在种级水平上为中等不相似,且2个区域鱼类群落均受到一定程度的干扰。研究区鱼类群落可划分为4个具有显著性差异的类群(p<0.05),分别位于示范区B区和对照区南部站位(类群Ⅰ)、对照区北部站位(类群Ⅱ)、示范区A区和B区交界处(类群Ⅲ)和示范区A区(类群Ⅳ)。类群Ⅰ和Ⅲ的平均相异性指数为53.88%,贡献率排前3位的分歧种为吉打副叶鲹(Alepes djedaba)、蓝圆鲹(Decapterus maruadsi)和竹荚鱼(Trachurus japonicus);类群Ⅲ和Ⅳ的平均相异性指数为48.85%,贡献率排前3位的分歧种为竹荚鱼、短吻鲾(Leiognathus brevirostris)和花斑蛇鲻(Saurida undosquamis)。水温和化学需氧量是显著影响研究区鱼类群落结构的主要环境因子,溶解氧和浮游植物密度的影响稍弱。

Timely assessment of fish resources in state-level marine ranching demonstration zone is important in promoting the construction of marine ranching.Based on the fishery resources survey data in the southern area of Guangxi Yintan in April 2022,we analyzed the characteristics of fish resources,community stability,fish community structure and their correlation with environmental factors to provide references for research on the ecological effects of marine ranching in Beibu Gulf.The results show that the fish individual density,biomass density and number of species in the demonstration zone were higher than those in the control zone.The fish species composition in the demonstration and control zones was moderately dissimilar at species level.In addition,fish communities in both zones were somewhat disturbed.The fish community in the survey area was divided into four significantly different clusters(p<0.05),which were located in the southern station of the demonstration zone B and the control zone(Cluster I),the northern station of the control zone(Cluster II),the junction of the demonstration zone A and B(Cluster III),and the demonstration zone A(Cluster IV).The average dissimilarity index of Cluster I and III was 53.88%,and the divergent species that ranked in the top three in terms of their contribution were Alepes djedaba,Decapterus marauds and Trachurus japonicus,while the average dissimilarity index of Cluster III and IV was 48.85%,with the top three divergent species(T.japonicus,Leiognathus brevirostri and Saurida undosquamis)contributing to the dissimilarity index.Water temperature and chemical oxygen demand were the main environmental factors significantly influencing the structure of the fish community in the survey area,while dissolved oxygen and phytoplankton density had a slightly weaker effect.