Table_4_Assemblage Structure of the Ichthyoplankton and Its Relationship With Environmental Factors in Spring and Autumn off the Pearl River Estuary.DOCX

Ichthyoplankton assemblages and their relationship with environmental variables are investigated in waters off the Pearl River Estuary in spring and autumn of 2019. Of 80 ichthyoplankton taxa identified using DNA barcode and morphological methods, 61 are identified to species. The most abundance families (Carangidae, Trichiuridae, Mullidae, and Scombridae) account for 61.34% of the horizontal total catch in spring, while Menidae and Carangidae are the most abundant families identified in autumn, accounting for 89.72% of the horizontal total catch. Cluster analysis identifies three species assemblages in spring, and four in autumn based on horizontal trawls. Relationships between assemblage structure and environmental variables (in situ and remote sensed) are determined by canonical correspondence analysis. Ichthyoplankton assemblage structure appears to be strongly influenced by sea level anomalies, salinity, water depth, temperature at 10 m depth, and distance from shore. We demonstrate the efficacy of using DNA barcode to identify ichthyoplankton, and suggest how these data can be used to protect fish spawning grounds in waters off the Pearl River Estuary.

本研究于2019年春、秋两季对珠江口海域的鱼卵仔鱼（ichthyoplankton）类群组合及其与环境变量的关联展开调查。研究通过DNA条形码（DNA barcode）与形态学方法共鉴定出80个鱼卵仔鱼分类单元，其中61个可鉴定至物种水平。春季优势科为鲹科（Carangidae）、带鱼科（Trichiuridae）、羊鱼科（Mullidae）和鲭科（Scombridae），其水平拖网总渔获量占比达61.34%；秋季优势科为银口鱼科（Menidae）与鲹科，二者总渔获占比高达89.72%。基于水平拖网采样数据，聚类分析将春季鱼卵仔鱼划分为3个类群组合，秋季则划分为4个类群组合。本研究采用典范对应分析（canonical correspondence analysis）探讨了类群结构与原位及遥感获取的环境变量之间的关联，结果显示鱼卵仔鱼类群结构显著受海平面异常、盐度、水深、10米层水温及离岸距离的影响。本研究验证了DNA条形码技术用于鱼卵仔鱼物种鉴定的有效性，并提出了可利用本研究数据保护珠江口海域鱼类产卵场的可行方案。