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Assessing potential niche overlap of native and non-native fish species in Great Lake embayments using stable isotope analysis

Boot, Truman
The advent of shipping canals linking the Laurentian Great Lakes to the Atlantic within the past century has introduced numerous invasive species into the Great Lakes ecosystem. Including but not limited to: Dreissenid mussels ( Dreissena sp. ), Eurasian ruffe ( Gymnocephalus cernua ), and round gobies ( Neogobius melanostomus ). The lack of natural predators of these novel species has allowed a rapid range expansion and increased prevalence, resulting in widespread ecological changes in the aquatic environment of Great Lakes systems. Such changes are causing profound impacts on the highly valued nearshore environments, such as shallow embayments, and their associated ecological communities. This shift within the composition of nearshore fish communities has potentially altered the basal energy pathways of native fish species. Using preliminary stable isotope and diet composition data, our objective is to better understand the impact of these changes in energy pathways by investigating the ecological niches of select native and non-native species. Prey fish samples were collected during 2021 Michigan Department of Natural Resources (MDNR) bottom trawl and gill net surveys within Great Lake embayments. Muscle plugs were taken from each sample and analyzed for carbon, nitrogen, and sulfur stable isotopes. Each stomach of selected native and non-native species prey fish consisting of were observed, with prey items being identified and counted. Interpreting these potential shifts in niche spaces and subsequent energy resources will allow for an increased understanding of the adaptive capacity of Great Lake prey fish. In turn, this will greatly increase our knowledge of the various potential pathways utilized by higher trophic level, recreationally important fish within the embayments of the Great Lakes.
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University of Wyoming. Libraries
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Bioenergetics , Fisheries , Stable Isotope Analysis , Great Lakes , Energy Flow , Invasive Species , Freshwater Ecology
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