Habitat use and diets of round gobies in coastal areas of Lakes Michigan and Huron

The non-indigenous round goby (Neogobius melanostomus) has caused considerable impacts in the Laurentian Great Lakes.  We sampled round gobies in shoreline habitats and tributary systems of Lakes Michigan and Huron to determine patterns of habitat use and diet, including the extent dreissenid mussels were consumed.  Along the shoreline, round goby catch did not significantly differ based on the presence of emergent vegetation, but deeper habitats were preferred relative to shallow areas closer to shore.  In tributary systems, submerged aquatic vegetation in coastal lakes was preferred.  The majority of round gobies were small, generally between 3 and 7 cm, and had diets comprised mainly of zooplankton and dipterans with very few dreissenids.  Our results indicate that round gobies have invaded coastal areas inconsistently across habitat types and that the species can proliferate in the absence of dreissenid mussels which likely influences the severity of their impacts to the ecosystem.