Defining Movements and Spatial Distribution of Lake Whitefish in Northern Green Bay and Lake Michigan

LMLWF

January 2024 - December 2028

Understanding movements and spatial distributions of lake whitefish stocks is a critical step in determining which stocks serve as sources of recruitment for important fisheries occurring within different regions of the Great Lakes, especially in locations where recruitment has declined. Information on movements is particularly relevant to the management of lake whitefish in and around Big Bay de Noc (BBDN) in northern Green Bay, one of several places in Lake Michigan where recruitment declines have occurred. Recent studies using both conventional loop tags and acoustic telemetry indicate that most lake whitefish spawning in BBDN (i.e., tagged in November) enter Lake Michigan (97% of fish with acoustic tags) and loop tag recoveries suggest these fish contribute to fisheries as far south as Sheboygan, Wisconsin. Additionally, 25% of BBDN lake whitefish implanted with acoustic tags spent time in southern Green Bay where they also contribute to harvest based on loop tag recoveries. Conversely, acoustic tag detections showed that only small proportions (< 3%) of lake whitefish spawning in tributaries to southern Green Bay (a region where lake whitefish are thriving) and along the lakeside of the Door Peninsula spent time in BBDN. Collectively, these findings suggest that at least some of the lake whitefish recruitment occurring in BBDN is being “outsourced” to other portions of Lake Michigan and whitefish fisheries in and around BBDN may be largely supported by “local” recruitment with limited contributions from other spawning locations. However, it is possible that the low proportions of lake whitefish moving into northern Green Bay from southern Green Bay and the lakeside of the Door Peninsula still represent important contributions to fisheries occurring in and around BBDN. A better understanding of where lake whitefish go after spawning in BBDN and identifying which stocks or spawning locations support fisheries in and around BBDN represent critical research needs that have significant implications for lake whitefish management within the region, including management within 1836 Treaty waters. Previous research could not fully address these questions due to a lack of acoustic receiver coverage in the main basin of Lake Michigan and because fish were only tagged during spawning periods. Our proposed research includes efforts to expand receiver coverage in Lake Michigan and represents the next phase of a strategic plan to describe movements and spatial distributions of lake whitefish supporting fisheries in several locations within Lake Michigan.

• 1) Determine the proportion of lake whitefish spawning in BBDN that subsequently leave the area but return to spawn the following year
• 2) Determine seasonal residency of BBDN spawners in different areas of Lake Michigan (e.g., Lake Michigan proper, northern vs. southern Green Bay)
• 3) Determine the proportion of BBDN spawners detected in Lake Michigan near the Wisconsin coastal cities of Kewaunee, Two Rivers, and Sheboygan
• 4) Determine spawning locations of whitefish tagged in BBDN during April-June (non-spawning fish).

• Determining where lake whitefish go after spawning in Big Bay de Noc (BBDN) and which stocks support fisheries in and around BBDN represent critical research needs that have significant implications for whitefish management within the region.

• Benjamin Vasquez (University of Wisconsin Stevens Point) - bevasque@alumni.nmu.edu
• Daniel Isermann (Wisconsin Cooperative Fishery Research Unit)
• Daniel Dembkowski (University Of Wisconsin Stevens Point)
• Kevin Donner (Little Traverse Bay Bands Of Odawa Indians)
• Jared Homola (University Of Wisconsin Stevens Point)
• Scott Hansen (Wisconsin Department Of Natural Resources)
• David Caroffino (Michigan Department Of Natural Resources)
• Jason Smith (Bay Mills Indian Community)
• Lisa Izzo (University Of Tennessee - Knoxville Institute Of Agriculture)

• United States Geological Survey
• University of Wisconsin Stevens Point
• Little Traverse Bay Bands of Odawa Indians
• Michigan Department of Natural Resources
• Wisconsin Department of Natural Resources
• Sault Ste. Marie Tribe of Chippewa Indians
• Wisconsin Cooperative Fishery Research Unit
• Wisconsin Sea Grant
• United States Fish and Wildlife Service

• Great Lake Fish and Wildlife Restoration Act