Using eDNA to estimate juvenile salmon abundance in Fundy National Park

Abstract

Environmental DNA (eDNA) is an emerging field that shows many benefits such as low effort and cost-effective sampling of aquatic environments. However, a variety of environmental factors influence the conservation of eDNA in water which make direct correlations between eDNA and fish abundance difficult to research. This study seeks to understand if incorporating the hydrodynamics and environmental variability of a river network will allow us to estimate juvenile salmon abundance using eDNA. We used eDNA sampling techniques and the eDITH R-Package to estimate juvenile salmon abundance throughout a river network. Based on the results of the analysis, we compared the estimated abundance results to electrofishing data to determine the comparability of our eDNA method with electrofishing. Although our results did not correlate with electrofishing abundance, producing Spearman’s correlation coefficients of R = -0.47, R = -0.49, and R = 0.41, they laid a critical foundation for future work that will adjust eDNA concentrations based on environmental variables. While abundance could not be accurately estimated and significant findings were inconsistent across trips, with adjustments, eDITH has potential to estimate relative population changes and aid in general monitoring of aquatic species.