4 Discussion
The application of nondestructive techniques to monitor and characterize
fish diversity has drawn increasing worldwide attention for assessing
aquatic ecosystem health. Given that it is difficult and costly to
investigate fish diversity in large rivers, finding a new monitoring
method with applicable technology has drawn great attention. Negative
impacts of increasing anthropogenic activities on aquatic organisms,
especially fish, have been verified in the Pearl River and other rivers
and reservoirs connected with it (Wang et al., 2020b; Wang et al.,
2019a; Wang et al., 2018a; Wang et al., 2019b; Wang et al., 2021a). To
protect and maintain the health of subtropical river systems, we
investigated the fish diversity along a river continuum using a
combination of electrofishing and eDNA metabarcoding. Our results
presented evidence that eDNA can be used to monitor fish diversity in
this kind of aquatic ecosystem.