Habitat Use and Diet of the Round Goby (Neogobius melanostomus) in Coastal Areas of Lake Michigan and Lake Huron

Abstract

The non-indigenous round goby (Neogobius melanostomus) has caused considerable impact in the Laurentian Great Lakes. We sampled round gobies in shoreline habitats and tributary systems of Lake Michigan and Lake 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, submersed 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 few dreissenids. Our results indicate that the round goby has invaded coastal areas inconsistently across habitat types and that the species can proliferate in the absence of dreissenid mussels.

Round goby predation onDreissenain coastal areas of eastern Lake Michigan

“…Our results in conjunction with evidence on round goby diets (Cooper et al 2009;Ruetz et al 2009) suggest that round goby predation effects on Dreissena density are not uniform across coastal areas of eastern Lake Michigan. In our enclosure experiment, the presence of large round gobies (i.e., 5, 10, and 15 individuals/m 2 ) significantly decreased Dreissena abundance in Muskegon Lake.…”

“…We used round goby densities of 5-15 individuals/m 2 in enclosures, which are not uncommon in the Great Lakes (Ray and Corkum 2001;Barton et al 2005;Johnson et al 2005) with densities as high as 133 individuals/m 2 reported in areas of Lake Michigan (Chotkowski and Marsden 1999). However, the size and density of round gobies in cages were likely greater than round gobies inhabiting littoral habitats in Muskegon Lake given the size and number of round gobies collected in fyke nets (Cooper et al 2007(Cooper et al , 2009Ruetz et al 2007). …”

“…Diets of small round gobies are comprised of mostly non-mussel invertebrates, whereas diets of larger (47.5 cm) round gobies often contain a large proportion of Dreissena (Ray and Corkum 1997;Skora and Rzeznik 2001;Barton et al 2005;Campbell et al 2009). This shift in diet with size is important because round gobies found near our exclosure sites had mean standard lengths of 5-6 cm (Cooper et al 2007(Cooper et al , 2009, whereas round gobies used in the enclosure experiment were 47.5 cm TL. Therefore, many of the round gobies living in the littoral habitats associated with the exclosure experiment may have not yet shifted their diets from non-mussel invertebrates to Dreissena, which could explain the lack of a strong round goby predation effect on Dreissena density in our exclosure experiment.…”

“…The 24-mm exclosures allowed round gobies ( 15.0 cm TL) access to bricks while excluding larger predators (i.e., fish, mammals, birds, and turtles that were unable to pass through the 24-mm mesh). Round gobies too large to physically pass through the 24-mm mesh are seldom encountered in and around our study sites (Clapp et al 2001;Ruetz et al 2007;Cooper et al 2007Cooper et al , 2009). We assumed that any predation on Dreissena in the 24-mm-mesh exclosures was primarily due to the round goby because other small-bodied fishes, such as johnny darter (Etheostoma nigrum) or logperch (Percina caprodes), were unlikely to consume Dreissena (French and Jude 2001) and we encountered very few crayfish during our field work (CRR, personal observation).…”

“…These lakes are all connected directly to Lake Michigan, and the round goby is present in each lake (Cooper et al 2007(Cooper et al , 2009). …”