U.S. Geological Survey La Crosse, WI - UMESC - GSCP - UMR (UMESCP19GSCP)

Recently there has been an increased removal effort of Grass Carp Ctenopharyngodon idella (GRC) from the Lake Erie basin through traditional capture methods. Due to historically low catch per unit effort and low abundance of GRC in the Lake Erie basin, there has been interest from managers in the use of baits for attracting GRC to harvest locations in known spawning tributaries. A terrestrial plant-based bait for GRC, that contains corn and rapeseed has been shown to be a palatable and attractive formulation in multiple USGS laboratory trials conducted with tank/pond reared fish. Although the bait is being designed for management use in the Lake Erie basin, a robust assessment of their effectiveness is limited in power when tested in this region due to low GRC density. Grass carp are often associated with dense macrophyte beds such as hydrilla Hydrilla verticillate, Coontail Ceratophyllum demersum and American lotus Nelumbo lutea that are often difficult to fish effectively using traditional gear. Habitat selection by GRC is primarily driven by vegetation cover which was also linked to shoal habitats. It is unclear whether shallow nearshore or shallow offshore (shoal) habitats with dense vegetation cover is either more favorable to GRC or suitable for bait and algae deployment. To successfully evaluate the effectiveness of bait to aggregate GRC in targeted locations, preferred habitat must be decoupled from GRC behavior around application sites. The goal of this project is to evaluate GRC behavior around bait application sites in relation to control sites in different habitats. Grass Carp behavior around application and control sites will be monitored using acoustic telemetry arrays positioned around automated feeders.

Points of Contact

• James Wamboldt

  U.S. Geological Survey

  Principal Investigator