Unexpected appetites Metabarcoding reveals Grass carp Ctenopharyngodon idella foraging behaviors in the Great Lakes

Grass carp Ctenopharyngodon idella are an herbivorous fish species introduced to North America in the 1960s and now established throughout the Mississippi River basin and Laurentian Great Lakes. Despite increasingly intensified management efforts, limited information exists on their foraging ecology. Trophic interactions are one of the most basic components ofanimal ecology and inform risk to other species in the ecosystem. We used DNA metabarcoding of gut contents from captured grass carp ranging from 2019 to 2022 to evaluate spatial, temporal, and environmental patterns in diet composition across Lake Erie and Lake Michigan.