Using eDNA to Better Understand Habitat Use, Movements, and Spawning of Asian Carps in the Wabash River, IN

Environmental DNA (eDNA) technologies are being widely used to detect the presence of bigheaded carps (Silver and Bighead spp.) by natural resource management agencies. This technology may additionally help inform resource managers about spawning activity and behavior. Information of this type can be easily incorporated into an integrated pest management approach to manage these species.  There are currently 297 acoustically-tagged bigheaded carps in the Wabash River, IN, that are being passively and actively telemetered.  These tagged fishes offer a unique opportunity to conduct intensive eDNA sampling to determine whether spatiotemporal changes in eDNA detection are related to movements and spawning behaviors of bigheaded carps.  We thus attempted to link detections and quantities of bigheaded carp eDNA with changes in river flow, fish movements, and drifting egg densities.  Our data indicate that the presence and quantities of bigheaded carp eDNA are related to fish activities and river flows in the Wabash River. These data suggest that eDNA reconnaissance can provide highly useful information beyond presence or absence of bigheaded carps or other aquatic species of nuisance or conservation concern.