March 10, 2026
The Michigan Department of Natural Resources surveys the diverse and important Great Lakes fisheries every year between April and November. 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. This information directly informs fisheries management decisions — such as stocking levels or regulated catch limits — and provides data on the success of past actions.
Surveying for 2025 has concluded, and DNR fisheries biologists are now synthesizing the findings and preparing for next year’s surveys. Interested in what the surveys found? Check out the highlights from each research station’s survey efforts below.
The crew of the research vessel Lake Char began work on Lake Superior as soon as the ice melted and continued through early November. The Marquette Fisheries Research Station is responsible for work that focuses on monitoring fisheries resources, including culturally and economically important species. These include lake trout, which were recently declared recovered in Lake Superior, lake whitefish and burbot. Surveys are conducted annually or at periodic intervals to track key population trends to monitor overall health of fishery resources.
Data from the spring adult lake trout surveys on Lake Superior showed a slight increase in populations east of the Keweenaw Peninsula and slight declines west. The summer juvenile lake trout survey indicated slight declines in western and central areas (Ontonagon to Marquette) and slight increases in eastern waters (Munising to Grand Marais).
In June 2025, the RV Lake Char team surveyed Big Reef to assess lake trout populations. Big Reef is a popular lake trout sportfishing site, offshore about 30 miles north of Munising. A similar expedition to Klondike Reef was conducted in 2024 — to learn more about the crew’s roles, the fish sampling process and why this research is important for managing Michigan's fisheries, watch the Klondike Reef expedition short documentary.
While out near Big Reef, the crew surveyed the deepest waters of Lake Superior (and all the Great Lakes) — about 1,320 feet — to assess siscowet lake trout populations. Siscowet lake trout is one of the lake trout morphotypes in Lake Superior that are most abundant in the deepest parts of the lake. They finished the survey season with lake trout spawning survey work between Marquette and Munising in late October and early November. During the 2025 field season, 198,000 feet (37.5 miles) of survey gill net was deployed for these surveys at 91 sampling stations across Lake Superior.
Fisheries work in Upper Peninsula waters of Lake Michigan began shortly after ice-out with jaw tagging and acoustic transmitter tagging of walleye in Little Bay de Noc for movement studies of the species.
Fisheries assessment work in nearshore waters of lakes Michigan and Superior occurred during August and September. Crews sampled 20 locations (10 miles of trawling) in Lake Michigan’s Little Bay de Noc and Big Bay de Noc. Over 23,000 feet of survey gill net were deployed at 68 sampling stations spread across four locations in northern Lake Michigan (Big Bay de Noc, Little Bay de Noc, Naubinway and Manistique) and two locations in southern Lake Superior (Munising Bay and West Bay at Grand Marais). Catch data from these fall surveys allow researchers to assess changes in the fish community and populations of species such as walleye, yellow perch, smallmouth bass, northern pike, lake sturgeon and invasive Eurasian ruffe.
Three surveys accounted for the majority of the Great Lakes survey work for the Charlevoix Fisheries Research Station staff and the survey vessel Steelhead in 2025: the spring gill net survey, lakewide acoustic forage fish survey and bottom trawl survey.
Since 1997, the DNR has participated in a spring gill net survey in collaboration with other agencies responsible for fisheries management in Lake Michigan. The objective is to assess recreationally, commercially and ecologically important fish populations, with a focus on lake trout, burbot, lake whitefish and yellow perch in Michigan waters. Due to the broad area covered and multispecies focus, this survey provides the most comprehensive information on the status of Lake Michigan adult fish populations.
The spring gill net survey was conducted at eight ports this year: St. Joseph, South Haven, Saugatuck, Grand Haven, Arcadia, Leland, Elk Rapids and Charlevoix. Across all ports, more than 100,000 feet of experimental bottom gill net was deployed, and data was captured on more than 5,000 fish — including a 42.5-inch, 35-pound lake trout that researchers believe to have been stocked in 1995!
From late August to early September, the SV Steelhead and crew conducted the prey fish survey, a multiagency effort measuring the abundance of alewife, rainbow smelt, bloaters and other prey fish throughout Lake Michigan. This survey uses hydroacoustic (high-precision, recordable fish finder) gear. Results inform research and trout and salmon management in Lake Michigan, including the lakewide “predator-prey ratio” analysis to ensure prey fish can support the lake’s salmon and trout populations.
The hydroacoustic survey was comprised of 25 sections spanning nearshore and offshore regions around the basin. Areas surveyed this season by the SV Steelhead stretched around the Michigan shore from waters offshore of Beaver Island in the north to St. Joseph in the south.
Initial observations from this survey suggest that abundance of yearling and older (more than 1 year old) alewife is similar to that of recent years. However, numbers of young-of-year (less than 1 year old) were low at most ports except those in southern Lake Michigan. Unlike young-of-year alewife, other fish — including bloater, rainbow smelt, yellow perch and stickleback — seemed to have experienced above-average recruitment in 2025, with higher abundance than typically observed in the acoustic survey.
The SV Steelhead crew completed the annual bottom trawl survey in September and October at three ports (South Haven, Grand Haven and Pentwater). Ten trawl samples were collected at each port, covering a range of water depths from 25 feet to 120 feet. This survey provides information on the overall status of the nearshore fish community, including the presence, range expansion and effects of invasive species, and the status of yellow perch recruitment. This year had the highest catch of yellow perch since 2012 for this survey, which, with luck, could portend an improved yellow perch fishery over the next several years.
Charlevoix Fisheries Research Station staff also used small vessels for targeted surveys in 2025. Staff assisted Central Michigan University researchers with scuba surveys of native freshwater mussel populations in large rivers. Staff also used long-term deployment of egg sampling equipment to enumerate lake whitefish egg deposition on spawning shoals in Big Bay de Noc and in Good Harbor Bay. In addition to egg sampling, staff partnered with the U.S. Geological Survey to tag adult lake whitefish in Bay de Noc with acoustic transmitters to determine spawning behavior and site selection.
The research vessel Tanner and its crew from the Alpena Fisheries Research Station completed a full suite of fisheries assessments across Lake Huron during 2025, traveling from DeTour in the north to the Thumb Coast in the south, with many stops — including Saginaw Bay — in between. Data collected throughout the entire 2025 survey season will be examined, shared with partners and used to update models and decision tools that help inform fisheries managers on the status of lake trout, walleye, yellow perch and other important species across Lake Huron.
Fieldwork began in April with the annual lake trout gill net survey, which sampled more than a dozen stations across U.S. waters of the main basin of Lake Huron. Findings from the spring survey showed young, wild lake trout continuing to survive well and join the adult population, along with stable adult lake trout abundance, low annual mortality and strong natural reproduction in northern Lake Huron. While survival of stocked lake trout is lower than desired, these findings bode well for decades-long efforts to promote lake trout recovery after the negative effects of overfishing and invasive sea lamprey in the early to mid-1900s.
Early and midsummer saw the station’s vessels and crew assist partners with maintenance of acoustic receivers in Saginaw Bay, which are part of the Great Lakes Acoustic Telemetry Observation System. This equipment and other receivers in the GLATOS network “listen” for signals from a variety of fish species that have been implanted with acoustic transmitters. This information helps scientists determine individual fishes’ movement, habitat use and mortality. Recent acoustic transmitter tagging efforts in Lake Huron have focused on lake trout, lake whitefish, walleye, lake sturgeon and cisco.
The RV Tanner crew also completed the sixth annual outer Saginaw Bay hydroacoustics and midwater trawling survey to support a multiagency evaluation of cisco rehabilitation efforts. Cisco, commonly called lake herring by anglers, were once abundant in Lake Huron. The goal of rehabilitating this species is to bring it back both for angling opportunity and its role as an important piece of the food web.
In late August, the RV Tanner again departed for Saginaw Bay for the annual September Saginaw Bay fish community survey. This year had the second highest experimental gill net catch rate ever recorded for yearling walleye, with the total catch rate of walleye increasing but remaining in the range of values observed since the population recovered in the late 2000s. Catch rates of adult yellow perch remain low, and biologists continue to use data from this survey to inform fisheries management under the guidance of the recently published Walleye and Yellow Perch Recreational Management Plan for Saginaw Bay.
Three juvenile lake sturgeon stocked as part of recent restoration efforts in the Saginaw River watershed were captured during the Saginaw Bay fish community survey. This is promising, demonstrating that small, hatchery-reared sturgeon can survive after they are released into the wild.
Immediately after the conclusion of the Saginaw Bay survey in early October, the Alpena crew took one of its small vessels, the RV Smolt, north to the Les Cheneaux Islands for the fish community survey; yellow perch catch rates on this survey were comparable to previous years.
The 2025 field season for the Lake St. Clair Fisheries Research Station began in March, with staff using the research vessel Mooneye electrofishing boat to target northern pike on Lake St. Clair for tagging and collecting age structures. None of the northern pike previously implanted with acoustic telemetry tags (in 2023-2024) were caught, but several of these fish were detected with a portable tracking unit. The age structures were used to estimate age and assess long-term trends in growth rates. Results indicated stable northern pike growth rates, which contrasts with growth trends of other fish that feed primarily on the lower food web (e.g., yellow perch and lake sturgeon). Those other fishes have experienced reduced growth rates following increased water clarity in Lake St. Clair.
April and May also saw the RV Mooneye on Lake St. Clair, this time collecting smallmouth bass for acoustic tagging. The ongoing acoustic telemetry work is part of a larger effort to track movement of smallmouth bass throughout the St. Clair-Detroit River System and western Lake Erie and is being done with partners from the Ontario Ministry of Natural Resources and Ohio Department of Natural Resources. Smallmouth bass are a top predator in this Great Lakes connecting waterway and are highly sought by recreational anglers in what is widely considered a world-class fishery.
The research vessel Channel Cat and its crew began large vessel work with a spring trawl survey in Lake St. Clair’s Anchor Bay. The trawl survey provides a snapshot of yellow perch abundance and growth — results continue to highlight the poor growth of Lake St. Clair perch due to changes in nutrients and invertebrate forage brought on by invasive zebra and quagga mussels.
After spring trawling, the RV Channel Cat immediately moved to the north channel of the St. Clair River for the annual June setline survey for lake sturgeon. A total of 83 lake sturgeon were caught and tagged, including 32 fish that were captured in previous survey efforts. This survey continues to provide fisheries biologists with the data needed to manage the largest naturally reproducing sturgeon population in the Great Lakes.
July brought annual binational lakewide fish community survey, conducted in cooperation with the Ontario Ministry of Natural Resources and the U.S. Fish and Wildlife Service. Catch rates were higher in Canadian waters than in U.S. waters, with overall catch rates being about six times higher in Ontario. Abundant natural shoreline, higher turbidity and better gear efficiency due to shallower water are possible contributors to the higher catch rates in Canada. The U.S. shoreline is primarily hardened shoreline, such as sea walls, leading to poor fish habitat and greater shoreline water depth, which makes it easier for fish to elude the survey nets.
In August, assessment efforts shifted to trawling with the annual Lake Erie trawl survey and the annual Lake St. Clair lake sturgeon trawl survey. The Lake Erie survey, which is used to assess the abundance of forage fish and young-of-year walleye and yellow perch in Michigan waters of the west basin, documented increased reproduction for both species compared to 2024, including the second-highest catch rate of juvenile yellow perch in the time series. However, low survival of young perch to older ages continues to present a challenge for fishery managers and anglers alike.
The Lake St. Clair trawl survey resulted in the capture of six lake sturgeon (all first-time captures) that were tagged and released. Each sturgeon was implanted with an acoustic telemetry tag to track their movement and habitat use. These were the first lake sturgeon caught directly from Lake St. Clair to be tagged with acoustic tags!
Trawling work continued into September, when the RV Channel Cat joined the RV Tanner for the Saginaw Bay fish community survey. The catch rates of young-of-year walleye and yellow perch in the Saginaw Bay trawls were high, and forage abundance was above the average measured during the past 10 years.
The survey season for the RV Channel Cat concluded the first week of October with the Lake Erie walleye index survey, which measures the abundance of yearling and older walleye. Walleye catch rates were down from 2024, which was likely due to the record-high fall water temperatures, delaying annual migration of walleye back to the west basin.
Field staff ended the year working on the Lake St. Clair nearshore electrofishing assessment from the RV Mooneye. This survey sampled over 3,000 individual fish representing 27 species — indicating a diverse fish community comprised of both sport and nongame fishes. Final data analysis from all 2025 surveys is ongoing, and results will be shared with partners to promote sound, scientific fisheries management in the international waters of the region.
Every year, DNR staff known as “creel clerks” survey Great Lakes anglers to collect valuable information that help inform decisions for managing Michigan’s fisheries. In 2025, 27 creel clerks conducted angler surveys from January to November at 84 locations across lakes Michigan, Superior, Huron and Erie. During the survey period, clerks interviewed over 20,000 angler parties and collected nearly 6,000 biological fish samples for age and growth analyses.
The survey found that anglers spent over 4 million hours fishing in the Michigan waters of the Great Lakes. Approximately 3.22 million fish were caught, of which 1.58 million fish were kept and 1.64 million fish were released. The most fishing effort occurred on Lake Huron, followed by lakes Michigan, Erie and Superior. Angler harvest in the Great Lakes was dominated by walleye and yellow perch, followed by Chinook salmon, lake trout, coho salmon and rainbow trout.
In 2025, a special angler survey was conducted on Isle Royale to provide updated information needed to manage this unique fishery. Three creel clerks were stationed at different locations on the island from June to August and visited campsites, docks and main harbors to conduct interviews, as well as traveling the coastline by boat to count the number of anglers fishing.
Survey results found that anglers took over 9,700 trips and spent over 33,000 hours fishing in the Lake Superior waters around Isle Royale. Approximately 19,500 fish were caught, of which 5,800 were kept and 13,700 were released. Lake trout were the most sought-after species, representing 82% of the total catch. Other species making up a significant portion of the catch included northern pike, brook trout and yellow perch. Most of the anglers fishing at Isle Royale were from Michigan, followed by Minnesota and Wisconsin, but anglers from 14 other states also visited the island during the 2025 survey.
For further information on DNR research stations, vessels and fisheries research, visit Michigan.gov/FishResearch.
Accompanying photos are available below for download. Caption information follows.
