2025 Midwest Fish & Wildlife Conference

AUTHORS: Gwendolyn Phillips, Lake Superior State University; Elliana Prow, Lake Superior State University; Jose Bonilla-Gomez, U.S. Fish and Wildlife Service - Alpena; Ben Breaker, U.S. Fish and Wildlife Service - Green Bay; Kennan Bruening, U.S. Fish and Wildlife Service - Green Bay; Lucas Chorba, Lake Superior State University; Ethan DePauw, Lake Superior State University; Brett Diffin, Grand Traverse Band of Ottawa and Chippewa Indians; Silas Dunn, Lake Superior State University; Simon Freeman, Bay Mills Indian Community; Ryan Grow, Sault Ste. Marie Tribe of Chippewa Indians; Ian Harding, Red Cliff Band of Lake Superior Chippewa; Chris Hessell, Grand Traverse Band of Ottawa and Chippewa Indians; Andrew Honsey, USGS Great Lakes Science Center; Joshua Hug, U.S. Fish and Wildlife Service - Green Bay; Samuel Johnston, Oklahoma Department of Wildlife Conservation; Jory Jonas, Michigan Department of Natural Resources; Kevin Kapuscinski, Lake Superior State University; Kevin McDonnell, Minnesota Department of Natural Resources; Gary Michaud, Little Traverse Bay Bands of Odawa Indians; Erik Olsen, Grand Traverse Band of Ottawa and Chippewa Indians; Paul Ripple, Bay Mills Indian Community; Katherine Skubik, Little Traverse Bay Bands of Odawa Indians; Jason Smith, Bay Mills Indian Community; Mason Spiess, Lake Superior State University; Jacob Synnott, U.S. Fish and Wildlife Service - Green Bay; Jack Tuomikoski, Sault Ste. Marie Tribe of Chippewa Indians; Christina VanDoornik, Little River Band of Ottawa Indians; Sarah Woody, U.S. Fish and Wildlife Service - Green Bay; Jonathan Doubek, Lake Superior State University


ABSTRACT: Lake whitefish (Coregonus clupeaformis) adult abundances have declined in recent decades in many regions of the upper Great Lakes. Potential mechanisms underlying these declines include, but are not limited to, a decrease in suitable spawning habitat, interactions with invasive species, and poor recruitment. Agencies have been monitoring larval lake whitefish to estimate abundance across the lakes in the spring after ice-off, when larvae are commonly found in shallow waters. However, most data on larval lake whitefish are collected during the day in shallow waters, typically on beaches (≤1 m water depth) and/or nearshore (1-10 m water depth). In order to accurately estimate an age-0 abundance index we need to know where and when to sample for larval coregonines, as not much is known about their early life ecology. More information using standardized sampling along a large spatiotemporal scale is needed to test whether larval lake whitefish abundances differ between day and night and beach and nearshore habitats to better monitor trends in relative abundance. Through an upper Great Lakes wide collaboration, we are processing ~30 paired day-night and beach-nearshore samples across 14 sites from 2023 and 2024, resulting in about 100 total samples. We identified collected fish as coregonine or non-coregonine, and coregonine samples are being identified to species using genetics. Preliminary results indicate that relative abundance of larval coregonines is higher at night versus day and higher on the beach versus nearshore waters. Additional samples will be quantified this fall to add to the existing dataset. Results will improve our understanding of larval coregonine ecology and possibly inform management.