The Consequences of Non-Native Species Invasions on the Contemporary and Historic Trophic Ecology of Native Sport Fish in a Lake Michigan Embayment

<p>The widespread establishment of dreissenid mussels (<em>Dreissena spp.</em>) in Lake Michigan has strongly altered energy flow by sequestering nutrients in nearshore benthic habitats. Despite these ecosystem changes, little is known about their influence on resource partitioning in nearshore fish communities. Here we use stable isotope analysis to characterize the contemporary fish community and historic walleye (<em>Sander vitreus</em>) population of Lake Michigan’s Little Bay de Noc. We found species-specific differences in the δ¹⁵N and δ¹³C values for 14 fish species. High degrees of niche overlap between walleye, northern pike (<em>Esox lucius</em>), smallmouth bass (<em>Micropterus dolomieu</em>) and yellow perch (<em>Perca flavescens</em>) indicating shared use of common prey items including round goby (<em>Neogobius melanostomus</em>)]. As length increased, northern pike and smallmouth bass increased their reliance on nearshore resources, while walleye increased reliance on pelagic resources. Isotope analysis over a 31-year time series coincident with the invasion of dreissenid mussels suggests that alterations in energy dynamics influencing walleye were dictated by varied responses from dominant prey items. Furthermore, sex-specific differences in walleye spawning movements indicated that females make significantly greater movements than males possibly driven by higher energetic and reproductive demands. This study improves our understanding of the Lake Michigan ecosystem by informing how whole-scale shifts drive trends in important sport fish communities.</p>

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biology

Year dc:date.available

2020

Author dc:creator

• Whitinger, John

Contributors dc:contributor

• Brandon Gerig

• aquatic invasive species
• stable isotopes
• Sander vitreus
• dreissenid mussels
• energy flow
• nearshore shunt
• sport fish
• Aquaculture and Fisheries

Repository record dc:identifier

https://commons.nmu.edu/theses/640

OAI identifier oai:identifier

oai:commons.nmu.edu:theses-1676