Pimushe

Temperature and dissolved oxygen measurements were collected from the deepest basin in Pimushe Lake, which is located partially within the Leech Lake Reservation, on August 7th, 2025, to evaluate the quantity and quality of cold, oxygenated water (oxythermal habitat) available to coldwater fish species such as Cisco, also known as Tullibee, the most sensitive coldwater species present in this lake. During the summer, Cisco require a layer of oxythermal habitat that contains water temperatures below 21.2 degrees C (70.2 degrees F), and dissolved oxygen concentrations above 3.0 mg/L. This layer can be characterized using a single variable, TDO3, the temperature at which dissolved oxygen decreased to 3.0 mg/L. During this survey, TDO3 was 21.6 degrees C (70.9 degrees F), which indicates that oxythermal conditions were unsuitable for coldwater species at the time of the survey. Data collected by the Minnesota Department of Natural Resources during the late summer period of maximum oxythermal stress (July 26th to August 24th) in 2008 indicated unsuitable oxythermal habitat, when the oxythermal habitat layer was not present. However, a survey completed in 2024 did indicate marginal habitat for Cisco, with a TDO3 of 20.5 degrees C. When inadequate oxythermal habitat is available coldwater species 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 Pimushe Lake, which is located partially within the Leech Lake Reservation, on August 7th, 2025, to evaluate the quantity and quality of cold, oxygenated water (oxythermal habitat) available to coldwater fish species such as Cisco, also known as Tullibee, the most sensitive coldwater species present in this lake. During the summer, Cisco require a layer of oxythermal habitat that contains water temperatures below 21.2 degrees C (70.2 degrees F), and dissolved oxygen concentrations above 3.0 mg/L. This layer can be characterized using a single variable, TDO3, the temperature at which dissolved oxygen decreased to 3.0 mg/L. During this survey, TDO3 was 21.6 degrees C (70.9 degrees F), which indicates that oxythermal conditions were unsuitable for coldwater species at the time of the survey. Data collected by the Minnesota Department of Natural Resources during the late summer period of maximum oxythermal stress (July 26th to August 24th) in 2008 indicated unsuitable oxythermal habitat, when the oxythermal habitat layer was not present. However, a survey completed in 2024 did indicate marginal habitat for Cisco, with a TDO3 of 20.5 degrees C. When inadequate oxythermal habitat is available coldwater species are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.

A targeted survey of nearshore fish species in Pimushe Lake, which lies partially within the boundaries of the Leech Lake Reservation, was conducted on August 19-20, 2024, by Index of Biological Integrity (IBI) Program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack electrofishing was completed at all 18 sampling stations, but eight stations were sampled from the boat due to site conditions. Similarly, a 50-foot seine was used to sample seven stations, a 15-foot seine was used to sample four stations, and site conditions (e.g., dense aquatic vegetation and soft substrate) prevented the use of a seine at seven stations. Nearshore sampling captured 16 species of fish including four species that are intolerant of disturbance (i.e., Blackchin Shiner, Blacknose Shiner, Iowa Darter, and Rock Bass) and one species that is tolerant of disturbance (i.e., Fathead Minnow). The nearshore data was combined with gill net and trap net data from a July 2022 survey to describe the fish community and provide a Fish-based IBI (FIBI) score. The FIBI uses fish community data to measure a lake's health, and the types of fish species present can help identify any stressors that may be negatively affecting the lake environment. In Minnesota lakes, certain fish species cannot survive without clean water and a healthy habitat (e.g., Blackchin Shiner, Iowa Darter, and Rock Bass), while other species are tolerant of degraded conditions (e.g., Black Bullhead, Fathead Minnow, and Green Sunfish). The FIBI score, composed of several fish community diversity and composition metrics, indicates the overall health of a lake by comparing it to what is expected for a healthy lake. For additional information on the FIBI, search for "lake index of biological integrity" on the mndnr.gov website. Temperature and dissolved oxygen measurements were also collected from the deepest basin in Pimushe Lake on August 19th, 2024, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Cisco, also known as Tullibee, the most sensitive coldwater species present in this lake. During the summer, Cisco require a layer of oxythermal habitat that contains water temperatures below 21.2 degrees C (70.2 degrees F) and dissolved oxygen concentrations above 3.0 mg/L. Based on the profile from the deepest basin, the water temperature decreased below 21.2 degrees C (70.2 degrees F) at 18.5 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 21.8 feet at the time of sampling. The thickness of this layer of water in the water column was 3.2 feet, indicating that oxythermal habitat was present for Cisco. Further, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was 20.5 degrees C (68.9 degrees F). TDO3 values cooler than 21.2 degrees C (70.2 degrees F) indicate that oxythermal conditions were suitable for Cisco at the time of the survey. Data collected by the Minnesota DNR during the late summer period of maximum oxythermal stress in 2008 indicates unsuitable oxythermal habitat at the time of that survey. When inadequate oxythermal habitat is available, Cisco are squeezed into unfavorable, warmer water conditions and experience higher levels of stress. The FIBI and oxythermal habitat survey results will be considered when the biological health of the lake is assessed during the Mississippi River-Headwaters Watershed assessment process, which will be completed in coordination with MN Pollution Control Agency. You can help protect the fish community in Pimushe Lake by reducing runoff and maintaining natural shorelines.

Based on Minnesota DNR survey data, anglers target Black Crappie, Walleye, Largemouth Bass, Bluegill, and Rock Bass in Pimushe. See the full species list above for catch rates, size structure, and quality scores.

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

Pimushe has a maximum depth of 40 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Pimushe is from 2022.

Yes — Pimushe has confirmed starry stonewort and zebra mussel. Clean, drain, and dry your equipment to avoid spreading invasives to other waters.

Yes — the 2026 Minnesota DNR regulations list 1 special rule for Pimushe, covering sunfish. Special regulations override the statewide limits; see the fishing regulations section on this page. Verify current rules with the Minnesota DNR before keeping fish.