Predicting habitat use and trophic interactions of Eurasian ruffe, round gobies, and zebra mussels in nearshore areas of the Great Lakes

Abstract

The Laurentian Great Lakes have been subject to numerous introductions of nonindigenous species, including two recent benthic fish invaders, Eurasian ruffe (Gymnocephalus cernuus) and round gobies (Neogobius melanostomus), as well as the benthic bivalve, zebra mussel (Dreissena polymorpha). These three exotic species, or ''exotic triad,'' may impact nearshore benthic communities due to their locally high abundances and expanding distributions. Laboratory experiments were conducted to determine (1) whether ruffe and gobies may compete for habitat and invertebrate food in benthic environments, and (2) if zebra mussels can alter those competitive relationships by serving as an alternate food source for gobies. In laboratory mesocosms, both gobies and ruffe preferred cobble and macrophyte areas to open sand either when alone or in sympatry. In a 9-week goby-ruffe competition experiment simulating an invasion scenario with a limited food base, gobies grew faster than did ruffe, suggesting that gobies may be competitively superior at low resource levels. When zebra mussels were added in a short-term experiment, the presence or absence of mussels did not affect goby or ruffe growth, as few zebra mussels were consumed. This finding, along with other laboratory evidence, suggests that gobies may prefer soft-bodied invertebrate prey over zebra mussels. Studies of interactions among the ''exotic triad'', combined with continued surveillance, may help Great Lakes fisheries managers to predict future population sizes and distributions of these invasive fish, evaluate their impacts on native food webs, and direct possible control measures to appropriate species.

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

“…The cause of the differential habitat use (i.e., preference for vegetation) by round gobies in the two types of coastal ecosystems is unclear. Laboratory studies demonstrated a preference for vegetated habitats over bare substrate (Bauer et al 2007, Savino et a1 2007, which is consistent with our findings in drowned river mouth lakes and those of Cooper et al (2007). However, aquatic macrophytes (presentlabsent or simple/complex) were not a significant environmental factor associated with round goby catch in shallow areas of the Lake Huron-Lake Erie corridor (Dopazo et al 2008), which is consistent with our findings in fringing systems.…”

“…However, in many coastal areas where hard substrates are not readily available, substantial round goby catches have been reported (Cooper et al 2007 dominant physical structure in many Great Lake coastal habitats, especially those lacking hard substrates (Uzarski et al 2005, Cooper et al 2007). In laboratory experiments, the round goby preferred macrophyte and cobble substrates comparably and more so than open, unvegetated habitats (Bauer et al 2007, Savino et al 2007. Similarly, field research in coastal riverine wetlands along the eastern shoreline of Lake Michigan showed that round goby catch was highest in lake habitats dominated by submersed aquatic vegetation and lowest in habitats dominated by water lily (Nuphar advena) or bare substrate (Cooper et al 2007).…”

Secondary invasion of the round goby into high diversity Great Lakes tributaries and species at risk hotspots: potential new concerns for endangered freshwater species

“…One species, which may be of particular concern, is the threatened eastern sand darter (Ammocrypta pellucida), which prefers well-oxygenated sand substrates (Holm and Mandrak 1996;Drake et al 2008). Although previous studies have shown that round goby prefer cobble or gravel substrates, and not sand (Ray and Corkum 2001;Bauer et al 2007), there is also evidence that large round gobies force juveniles from preferred rocky habitats into less desirable sandy habitats (Ray and Corkum 2001). This suggests that at high enough densities, there is potential for competition between round goby and eastern sand darter (Appendix Table 3).…”

Use of wetland versus open habitats by round gobies in lakes Michigan and Huron: Patterns of CPUE, length, and maturity

“…The Beaver Archipelago had high catches of round gobies in wetlands, followed by moderate CPUE in Les Cheneaux wetlands, and extremely low CPUE in Saginaw Bay wetlands. Previous laboratory experiments have shown that round gobies prefer complex habitats of rock and macrophyte cover (Bauer et al, 2007), which may explain why there were more round gobies in the wetlands than the open water in the Beaver Archipelago. Our findings of moderate round goby CPUE in wetlands and no difference in CPUE between habitats at Les Cheneaux sites are similar to the findings of Cooper et al (2009).…”