Gunflint

Temperature and dissolved oxygen measurements were collected from the deepest basin in Gunflint Lake on August 11th, 2025. This was done to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Trout, the most sensitive coldwater species present in this lake (Cisco, also known as 'Tullibee', are also present). Lake Trout require a layer of oxythermal habitat that contains water temperatures below 8.8 degrees C (47.8 degrees F) and dissolved oxygen concentrations above 3.0 mg/L. Based on data collected from the deepest basin (maximum sampled depth was 98.4 feet), the water temperature decreased to 8.8 degrees C (47.8 degrees F) at 40.5 feet and the dissolved oxygen concentration stayed greater than 3.0 mg/L for the entire sampled depth. This layer in the water column was 57.9 feet, indicating oxythermal habitat for Lake Trout was present. Further, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was never reached because dissolved oxygen remained above 3.0 mg/L throughout the sampled depths. In this case, the minimum temperature, 6.0 degrees C (42.8 degrees F), was substituted as TDO3. TDO3 values cooler than 8.8 degrees C (47.8 degrees F) indicate that oxythermal conditions were suitable for Lake Trout at the time of the survey. Data collected by the Minnesota Department of Natural Resources during the period of maximum oxythermal stress (July 26th to Aug 24th) in 10 years, between 1976-2024, also indicated suitable oxythermal habitat in all years surveyed, with the least favorable conditions recorded in 2011 when the suitable oxythermal habitat layer was 23.3 feet thick. When adequate oxythermal habitat is not available, Lake Trout are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.

Temperature and dissolved oxygen measurements were collected from the deepest basin in Gunflint Lake on August 11th, 2025. This was done to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Trout, the most sensitive coldwater species present in this lake (Cisco, also known as 'Tullibee', are also present). Lake Trout require a layer of oxythermal habitat that contains water temperatures below 8.8 degrees C (47.8 degrees F) and dissolved oxygen concentrations above 3.0 mg/L. Based on data collected from the deepest basin (maximum sampled depth was 98.4 feet), the water temperature decreased to 8.8 degrees C (47.8 degrees F) at 40.5 feet and the dissolved oxygen concentration stayed greater than 3.0 mg/L for the entire sampled depth. This layer in the water column was 57.9 feet, indicating oxythermal habitat for Lake Trout was present. Further, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was never reached because dissolved oxygen remained above 3.0 mg/L throughout the sampled depths. In this case, the minimum temperature, 6.0 degrees C (42.8 degrees F), was substituted as TDO3. TDO3 values cooler than 8.8 degrees C (47.8 degrees F) indicate that oxythermal conditions were suitable for Lake Trout at the time of the survey. Data collected by the Minnesota Department of Natural Resources during the period of maximum oxythermal stress (July 26th to Aug 24th) in 10 years, between 1976-2024, also indicated suitable oxythermal habitat in all years surveyed, with the least favorable conditions recorded in 2011 when the suitable oxythermal habitat layer was 23.3 feet thick. When adequate oxythermal habitat is not available, Lake Trout are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.

Gunflint is a 4009 acre lake located 48 miles northwest of Grand Marais. A public boat landing can be found in the southwestern corner of the lake. Gunflint is primarily managed for lake trout and walleye. The 2023 survey of Gunflint Lake was the second of three surveys scheduled to evaluate the lake trout and walleye populations. Lake trout abundance was similar to historical catches and met the current management goal and is above average for similar area lakes. Lake trout ranged from 7.8 to 27.2 inches with a mean length of 18.5 inches. Aging results found 12 different naturally reproduced year classes with the oldest fish being 26 years old. Naturally reproducing lake trout populations are unique in Minnesota lakes, anglers targeting lake trout should consider catch and release practices with safe handling procedures. Walleye gill net catches were similar to recent surveys but fell slightly below average and did not meet the current management goal. Walleye ranged from 8.9 to 27.9 inches with a mean length of 16.1 inches. Aging results showed individuals from 9 different year classes present in the population. The largest year class (3-year-old fish) coincides with the walleye fingerling stocking of 2020. The oldest fish collected was 17 years old. Back calculated growth rates appear to be relatively fast compared to other area lakes, with walleyes reaching 17.2 inches at age 5. Some large sized walleye exist in Gunflint Lake. Northern pike catches were somewhat low but similar to surveys conducted since 2011. Northern pike were relatively large and ranged from 18.2 to 43.9 inches with a mean length of 25.1 inches. Gunflint Lake has the potential to produce trophy northern pike. The smallmouth bass catch is above average for similar area lakes, and in the normal range for Gunflint Lake. Smallmouth bass collected ranged from 8.8 to 17.8 inches with a mean length of 14.2 inches. Overall, good numbers of smallmouth bass with many large sized fish should be of interest to anglers. Rock bass numbers are relatively good in Gunflint Lake but have been slowly declining since their peak in 2011. Yellow perch catch rates were similar to historic levels. Rainbow smelt were first seen in Gunflint Lake in the 1970s. Catches in small-mesh gill nets designed to sample smelt have varied considerably in this lake but were considered low in 2023. Although smelt are an excellent source of forage, their naturalization has also been associated with reproductive failures among cisco, walleye, and lake trout. Catch rates of cisco were slightly above average for Gunflint Lake but comparable to surveys since 2003. Cook County, Minnesota lakes continue to be susceptible to aquatic invasive species introductions and Gunflint does have spiny water flea prevalent within the lake. Invasive species have the potential to significantly alter fish communities and overall lake health. Anglers should clean watercraft and fishing gear, drain all water, and dispose of unused bait in the trash to prevent accidental introductions.

Based on Minnesota DNR survey data, anglers target Lake Trout, Walleye, Northern Pike, Rock Bass, and Smallmouth Bass in Gunflint. See the full species list above for catch rates, size structure, and quality scores.

Minnesota DNR records list public access for Gunflint. Check the DNR LakeFinder page for the launch type and directions before you go.

Gunflint has a maximum depth of 200 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Gunflint is from 2023.

Yes — Gunflint has confirmed spiny waterflea. Clean, drain, and dry your equipment to avoid spreading invasives to other waters.

Gunflint is a border water, so it follows Minnesota–Canada border-water regulations, which differ from inland Minnesota rules. Verify current rules with the Minnesota DNR before keeping fish.