AUTHORS: Max Monfort, University of Wisconsin La Crosse US Geological Survey Upper Midwest Environmental Science Center; James Wamboldt, US Geological Survey Upper Midwest Environmental Science Center; Matthew Acre, US Geological Survey Columbia Environmental Research Center; Andrew Mueller, US Geological Survey Columbia Environmental Research Center; Dustin Broaddus, US Geological Survey Columbia Environmental Research Center; Jacob Griffin, US Geological Survey Columbia Environmental Research Center; David Schumann, University of Wisconsin La Crosse
ABSTRACT: Grass Carp (Ctenopharyngodon idella) consumption of aquatic macrophytes can alter trophic dynamics when introduced to new aquatic ecosystems. Increased commercial captures and expansion into further reaches of the Upper Mississippi River (UMR) could have negative affects to these aquatic ecosystems. Efforts to control this highly mobile and illusive species in the UMR and Great Lakes Basins are a substantial challenge to managers. A potential bait for Grass Carp has been evaluated at other invasion fronts (e.g., Lake Erie), but its application in the UMR has not yet been fully recognized. We refined methods and utilized 2023 longitudinal movement data to describe the utility of automated bait delivery systems to aggregate Grass Carp in pool 19 of the UMR in 2024. Specifically, our objectives were to: (1) describe Grass Carp movement ecology within the riverscape before, during, and after bait application, and (2) determine Grass Carp movement responses to baiting; use of the baiting area, time occupied at baiting area, and the effective attraction distance from the baiting area. Grass Carp (n = 90) behavior was evaluated in response to the deployment of a novel Grass Carp specific bait via automated bait delivery systems in four distinct habitats using acoustic telemetry arrays from March-November 2024. If successful, these methods could provide an exploratory, yet innovative, Grass Carp management strategy for more efficient removals within the UMR and other invasion fronts.
