eDNA metabarcoding as a promising conservation tool for monitoring fish diversity in a coastal wetland of the Pearl River Estuary compared to bottom trawling.

Abstract The difficulty of censusing fish diversity hampers effective management and conservation in estuarine and coastal ecosystems, especially wetland ecosystems. Improved noninvasive fish diversity monitoring programs are becoming increasingly crucial for coastal ecosystems. In this study, we investigated fish diversity and its seasonal variation in the Nansha wetland ecosystem using environmental DNA (eDNA) metabarcoding and bottom trawling, and the two approaches were compared. With the combination of the two methods, the identified fish taxa included 78 species within 60 genera and 33 families, and five nontarget taxa were only identified by eDNA metabarcoding. Compared to the two surveys, eDNA metabarcoding identified a significantly greater number of fish species per site and per season than bottom trawling (p