A comparison of seasonal composition and structure of fish community between environmental DNA technology and gillnetting in the Pearl River Estuary, China

Non-destructive and cost-effective fish diversity monitoring approaches are needed for the management and protection of estuarine ecosystems. Environmental DNA (eDNA) technology is a promising, environmentally friendly technology that has been applied in fish diversity studies in estuarine ecosystems. In this study, we investigated the seasonal composition, diversity, and structure of fish community in the Pearl River Estuary (PRE) using eDNA technology and gillnetting. We identified 156 fish in the PRE, including 26 orders, 58 families, 93 genera, and 115 species according to eDNA technology. And eDNA technology provided more taxonomic composition information in the PRE than did gillnetting. Significant or highly significant seasonal differences in fish community composition and structure were detected between the wet and dry seasons. Fifteen and eight genus-level indicator taxa differed significantly between the two seasons according to eDNA technology and gillnetting, respectively. However, the significant differences detected in this study suggest that some taxa did not overlap between the two approaches. Therefore, fish diversity monitoring in the PRE should include a combination of eDNA technology and gillnetting for comprehensive fish community data analysis. Our findings have important implications for fish community monitoring and estuarine ecosystem management.