Every year from April to November, the Michigan Department of Natural Resources is on the Great Lakes, surveying the important and diverse Great Lakes fisheries. Crews from research stations in Marquette, Charlevoix, Alpena and Harrison Township gather data on fish populations, fish health and the presence and effects of invasive species. It’s vital information that directly informs fisheries management decisions — such as stocking levels or regulated catch limits — and provides data to help gauge the success of past actions.

With surveying for 2024 wrapped up, DNR fisheries biologists are now synthesizing the findings and preparing for next year’s surveys. Interested in what the surveys found? Check out highlights from each research station’s survey efforts.

– Lake Superior and northern Lake Michigan (Marquette Fisheries Research Station)

– Lake Michigan (Charlevoix Fisheries Research Station)

– Lake Huron (Alpena Fisheries Research Station)

– St. Clair-Detroit River System (Lake St. Clair Fisheries Research Station)

Lake Superior and northern Lake Michigan

The crew of the research vessel (RV) Lake Char began work on Lake Superior as soon as the ice melted and continued through early November. The Marquette Fisheries Research Station’s work focuses on lake trout, though species studied this year also included lake whitefish and burbot.

Data from the spring 2024 Lake Superior surveys showed a slight increase in adult lake trout populations in nearly all areas. The summer juvenile lake trout survey indicated slight increases in recruitment (reproduction and survival) on the west side of the Keweenaw and Munising areas and a slight decline in all other locations, with stable populations overall. During the field season, 257,100 feet (48.7 miles) of assessment gill net was deployed for these surveys at 123 sampling stations across the lake.

The RV Lake Char surveyed waters around Isle Royale in spring to assess the status of lake trout populations around the island. The crew also conducted surveys in the deepest waters of Lake Superior (and all the Great Lakes) — about 1,320 feet — to survey siscowet lake trout populations. The RV Lake Char crew finished the survey season with lake trout survey work at Klondike Reef, a remote location 40 miles from shore, in October and then surveyed nearshore lake trout spawning reefs near Munising in early November.

Nearshore Great Lakes fisheries assessment work from Upper Peninsula ports involved 10 miles of trawling in Lake Michigan’s Little Bay de Noc and Big Bay de Noc. In addition, over 25,000 feet of survey gill net was used in four locations in northern Lake Michigan (Big Bay de Noc, Little Bay de Noc, Naubinway and Manistique) and two locations in southern Lake Superior (Keweenaw Bay and Huron Bay). Catch data from these fall surveys provide useful metrics for assessing fish community change and populations of species including walleye, yellow perch, smallmouth bass, northern pike, lake sturgeon and invasive Eurasian ruffe.

This winter, the Marquette Fisheries Research Station staff will perform maintenance in preparation for the 2025 field season and process the samples and data collected during 2024. These surveys provided data for collaborations with researchers from Purdue University, University of Wisconsin-Milwaukee, State University of New York-Brockport, Michigan Technological University and Michigan State University.