2018-2023年珠江口鱼类群落结构变化及其与环境因子的关系

Interannual variation of fish communities and their environmental factors in Pearl River Estuary from 2018 to 2023

珠江口是中国重要的渔场和水产资源繁殖保护区。为掌握珠江口渔业资源现状及变化趋势,分别于2018—2023年春、秋季开展了6次底拖网调查,探究了珠江口海域鱼类群落结构组成及其与环境因子的关系,以期为渔业资源的科学管理和有效保护提供依据。结果显示,珠江口海域6个航次调查共鉴定鱼类168种,隶属于17目55科119属。优势种与重要种的组成以中小型底层鱼类为主,包括短吻鲾(Leiognathus brevirostris)、棘头梅童鱼(Collichthys lucidus)、前鳞骨鲻(Osteomugil ophuyseni)、鳓(Ilisha elongata)、七丝鲚(Coilia grayi)和红狼牙鰕虎鱼(Odontamblyopus rubicundus)。鱼类的平均质量资源密度和平均尾数资源密度均表现出明显的季节和年际差异,最高值分别出现在2020年秋季和2020年春季。聚类分析表明,春季鱼类群落结构可分为4组,表现为年际差异和空间差异并存。秋季鱼类群落结构可分为3组,仅表现出年际差异。典范对应分析(Canonical correspondence analysis,CCA)进一步揭示了春季鱼类群落结构主要受盐度、水温和水深的影响,而秋季则主要受透明度、活性磷酸盐、水深和水温影响。

The Pearl River Estuary is an important fishing ground and conservation area for aquatic resources in China.In order to understand the current situation and change trend of fishery resources in the Pearl River Estuary,we carried out six bottom trawl surveys in the spring and autumn of 2018–2023,and explored the composition of fish community structure in the Pearl River Estuary waters and its relationship with environmental factors,so as to provide a basis for scientific management and effective protection of fishery resources.The results show that a total of 168 fish species had been identified from the six surveys,belonging to 17 orders,55 families and 119 genera.The dominant and important species were mainly small and medium-sized bottom-layer fish,including Leiognathus brevirostris,Collichthys lucidus,Osteomugil ophuyseni,Ilisha elongata,Coilia grayi and Odontamblyopus rubicundus.The average stock density and tail stock density of fish showed both seasonal and interannual varia-tions among the six surveys,with the highest values in spring of 2020 and autumn of 2020,respectively.The cluster analysis shows that the fish community of spring surveys was divided into four groups with both interannual and spatial differences.However,the fish community in autumn surveys was divided into three groups with only interannual heterogeneity.Canonical correspondence analysis(CCA)indicates that salinity,water temperature and water depth were the main environmental factors affecting the community structure of fish in spring,while transparency,contents of active phosphate,water depth and water temperature were the important factors influencing fish community structure in autumn.