Holistic Impact Evaluation of Human Activities on the Coastal Fish Biodiversity in the Chinese Coastal Environment

Ecological qualities and resources in coasts are threatened by various human activities, such as pollution andfishery. Impact evaluation of environmental stressors over a widecoastal stretch has been limited due to lack of efficient andstandardizable biodiversity monitoring and assessment tools.Integrating environmental DNA (eDNA) and ecological traits, aholistic approach was developed to assess the impact of pollutionand aquaculture onfish biodiversity in Chinese coastal areas. Takingthe Yalujiang Estuary (YLJK) from the Yellow Sea and the Nan'aoIsland Area (NAO) from the South China Sea as cases, theperformance of the eDNA biomonitoring workflow was validated.First, the eDNA results of 22 sampling sites reached more than 85%of the asymptotes of species or ASVs in each area. A total of 115fishspecies in both areas were detected and NAO was 1.8 times richer than YLJK using eDNA and thefish eDNA composition wasconsistent with the historical data. eDNA recovered distinct variations offish sequence, taxonomic and functional diversity, and thecorresponding trends following the offshore distance between the two areas. Fish sequence diversity was decreased primarily byestuarine pollution factors (chemical oxygen demand and zinc) in the YLJK. Compared with no breeding areas, lowerfish sequencediversity was in breeding areas in the NAO. By integrating ecological traits, the eDNA approach offers promising opportunities forfuturefish biodiversity monitoring and assessment in national and global coastal environments.