Oral Presentation Freshwater Sciences 2023

Seeing through a fish’s eye: Using stable isotopes of fish eye lenses to understand life history (#82)

William W Fetzer 1 , Caroline Rosinski 1 , Andrew Muir 2 , Rosie Smith 3 , Heidi Swanson 3 , Ben Turschak 4 , Mark Vinson 5
  1. Zoology and Physiology, University of Wyoming, Laramie, WY, United States
  2. Great Lakes Fishery Commission, Ann Arbor, Michigan, USA
  3. Biology, University of Waterloo, Waterloo, Ontario, Canada
  4. Michigan Department of Natural Resources, Charlevoix, Michigan, United States
  5. United States Geological Survey, Ashland, Wisconsin, United States

Analytical techniques to re-create an individual fish’s trophic ecology are limited. Recent developments in marine systems suggest stable isotope analyses of fish eye lenses may provide a tool to re-create an individual fish’s feeding chronology throughout their life. These layers are comprised of crystalline proteins that maintain each layer’s structure and elemental composition, and are rich in carbon, nitrogen, and other elements that can be used for stable isotope analyses. Our research tests the utility of stable isotope analyses of fish eye lenses to retroactively describe feeding chronologies of individual fish throughout the duration of their life. Individual research objectives focus on evaluating this technique across three data-rich systems of Lake Trout and Arctic Char life history variation and evaluating preservation effects on the isotopic signatures of fish eye lenses. Across study systems, results uniformly highlight the utility of this technique to quantify individual life history variation and foraging plasticity, including migration between freshwater and brackish habitats, ontogenetic foraging differences among morphs, and individual foraging responses to fluctuations in prey availability. Early results are very promising and suggest this novel technique will be a valuable addition to the ecologist’s toolkit.