Environmental DNA monitoring and management of invasive fish: Comparison of eDNA and fyke netting

Abstract

The potential of environmental DNA (eDNA) methods to enhance the detection of invasive species during routine monitoring is of interest to management agencies. Here we applied the eDNA methodology concurrent with conventional detection techniques during two routine monitoring seasons to detect the presence of three invasive fish in Australia with contrasting spatial distributions (benthopelagic, pelagic and benthic): common carp (Cyprinus carpio), redfin perch (Perca fluviatilis) and Oriental weatherloach (Misgurnus anguillicaudatus). Our objectives were to compare the seasonal detection of the target species using eDNA and conventional detection (fyke nets), determine the relationship between catch per unit effort (CPUE) and DNA copy number and ascertain the best water location (surface vs. subsurface) for eDNA detection. Our results show that eDNA had a higher detection rate than fyke nets for Oriental weatherloach and redfin perch during both the autumn and spring surveys. Common carp was detected at all sites for both seasons using fyke nets and eDNA with the exception of one site during the autumn survey where common carp was captured using fyke nets but no carp eDNA was detected. Season had a significant effect on DNA concentration for common carp (P