Browsing by Subject "walleye"

Now showing 1 - 4 of 4
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    Data and R code for analysis of mercury concentration and food web differences in walleye and yellow perch from Minnesota lakes with and without invasive zebra mussels, 2019 - 2021
    (2023-02-24) Blinick, Naomi S; Ahrenstorff, Tyler D; Bethke, Bethany J; Fleishman, Abram B; Link, Denver; Nelson, Jenna KR; Rantala, Heidi M; Rude, Claire L; Hansen, Gretchen JA; nsblinick@gmail.com; Blinick, Naomi S; University of Minnesota Department of Fisheries, Wildlife, Conservation Biology; Minnesota Department of Natural Resources
    This dataset contains δ13C and δ15N stable isotope data for 3,765 biological samples (fish, littoral macroinvertebrates, and zooplankton) collected from 21 lakes between 2019 and 2021, collaboratively by the University of Minnesota and the Minnesota Department of Natural Resources. In addition, 403 samples have corresponding mercury data, based on laboratory analyses conducted by USGS (Tate et al. 2022).
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    Data and R code for analysis of walleye and yellow perch age-0 length in Minnesota's Large Lakes
    (2019-12-10) Hansen, Gretchen J A; Bethke, Bethany J; Ahrenstorff, Tyler D; Dumke, Josh; Hirsch, Jodie; Kovalenko, Katya E; LeDuc, Jaime F; Maki, Ryan P; Rantala, Heidi M; ghansen@umn.edu; Hansen, Gretchen; Minnesota Aquatic Invasive Species Research Center (MAISRC)
    Invasive species represent a threat to aquatic ecosystems globally; however, impacts can be heterogenous across systems. Documented impacts of invasive zebra mussels (Dreissena polymorpha) and spiny water fleas (Bythotrephes cedarstroemi; hereafter Bythotrephes) on native fishes are variable and context dependent across locations and time periods. Here, we use a hierarchical Bayesian analysis of a 35-year dataset on two fish species from 9 lakes to demonstrate that early life growth of ecologically important fishes are influenced by these aquatic invasive species. Walleye (Sander vitreus) grew more slowly throughout their first year of life, and were on average 12 or 14% smaller at the end of their first summer following invasion by Bythotrephes or zebra mussels, respectively. Yellow perch (Perca flavescens) growth was less affected by invasion. Yellow perch on average grew more slowly in their first year of life following invasion by zebra mussels, although this effect was not statistically distinguishable from zero. Early life growth of both walleye and yellow perch was less tightly coupled to degree days in invaded systems, as demonstrated by increased variance surrounding the degree day-length relationship. Smaller first-year size is related to walleye survival and recruitment to later life stages and has important implications for lake food webs and fisheries management. Future research quantifying effects of zebra mussels and Bythotrephes on other population-level processes and across a wider gradient of lake types is needed to understand the mechanisms driving observed changes in walleye growth.
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    Data in Support of Widespread declines in walleye recruitment following zebra mussel invasion in Minnesota lakes
    (2023-04-26) Kundel, H; Hansen, Gretchen J A; kunde058@umn.edu; Kundel, H; University of Minnesota Dr. Hansen Research Team
    Invasive zebra mussels (Dreissena polymorpha) alter lake ecosystems and can negatively affect first-year growth of walleye (Sander vitreus), potentially lowering walleye overwinter survival and recruitment success. Zebra mussel effects also vary among lakes, and walleye resilience to the effects of zebra mussels may vary depending on lake characteristics (e.g., depth, clarity) or fish community composition. To test these hypotheses, we used data from 1,438 surveys across 348 lakes collected between 1993 and 2019 to measure walleye recruitment, defined as relative abundance of age-0 walleye in their first fall. We fitted Bayesian hierarchical models to quantify the effects of zebra mussels on walleye recruitment while accounting for the effects of lake temperature, surface area, and water clarity. A before-after-control-impact (BACI)-like design was used to account for potential changes in recruitment due to factors other than zebra mussel invasion. Age-0 walleye recruitment to their first fall was ~41% lower (95% credible interval of 38 - 44%) in lakes containing zebra mussels compared to uninvaded lakes. Invaded lakes had higher recruitment prior to zebra mussel invasion than lakes that remain uninvaded. Conversely, walleye recruitment increased slightly (7% (95% credible interval 2 - 11%)) in lakes without zebra mussels over the same time period. Walleye recruitment was higher in larger lakes and lakes with lower water clarity. Water temperature, as indexed by degree days (base 5 °C), did not affect walleye recruitment. Our results demonstrate negative effects of zebra mussel invasion on walleye population dynamics at a landscape scale.
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    Zebra mussel invasion associated with higher reliance on littoral energy sources and higher mercury levels in walleye and yellow perch
    (2022-02) Blinick, Naomi
    Zebra mussels (Dreissena polymorpha), an aquatic invasive species, shift lake food resources from the pelagic to the littoral zone, while simultaneously altering physical habitat by increasing water clarity. Using stable isotope analysis, we find that walleye (Sander vitreus), a specialist piscivore with strict habitat requirements, and yellow perch (Perca flavescens), a generalist in both diet and habitat, respond similarly to food web and habitat differences in zebra mussel invaded lakes, with significant increases in littoral reliance from ~50% to ~75% for both species. We also report a correlated increase in mercury concentrations in fish tissue, which were 66% higher for adult walleye and 90% higher for adult yellow perch in lakes containing zebra mussels. Considering the importance of these fish for consumption, it is critical that we understand how changes to nutrient cycling and lake food webs ultimately increase toxin concentration in fish consumed by humans.