Mule

Mule Lake is a 525-acre lake with 7.31 miles of shoreline and a maximum depth of 47 feet located south of Longville, MN. A DNR owned public access is located on the western shore. The DNR has classified Minnesota's lakes into 43 different classes based on physical, chemical, and other characteristics. Mule Lake is in Lake Class 23; lakes in this class are generally deep and clear. Other area lakes in this class include Jack, Ponto, Stony, and Baby. The entire east shore is publicly owned and undeveloped. The lake is primarily managed for Northern Pike, Walleye, and Yellow Perch and secondarily for Smallmouth Bass, Largemouth Bass, Bluegill, and Black Crappie. An experimental catch and release regulation for Largemouth and Smallmouth Bass was modified in 2016 to a 14-20-inch protected slot limit with 1 over 20 inches in possession. The regulation was removed in 2021. Other regulations include an ongoing Walleye possession limit of 3 fish. Northern Pike catch rates were the highest ever observed with an average length and weight of 16.3 inches and 0.89 pounds. Walleye abundance has remained stable at roughly 3 fish per net and lengths ranged from 15 to 29 inches. Yellow Perch numbers in Mule are low compared to similar lakes, though were higher in 2023 than the previous eight surveys. Smallmouth Bass catch rate in the spring was a record high with fish up to 19 inches long sampled. Largemouth Bass catch rates resembled previous assessments with fish up to 17 inches sampled. Bluegill abundance was moderate, with an average size of 6 inches and over 9 inches sampled. Black Crappie were abundant, with an average length of 8 inches and fish up to 11 inches sampled. Other fish species that anglers can expect to encounter in Mule Lake include Pumpkinseed, Rock Bass, and White Sucker. People can have significant impacts on lakes and the fish populations they support. Harvest, lakeshore development, removal of shoreline vegetation, and introductions of invasive species can all adversely affect fish populations. Currently, no aquatic invasive species (AIS) have been identified in Mule Lake. AIS are moved from infested to non-infested waters by anglers, boaters, and lake shore owners and can adversely impact lakes and fish populations. To avoid spreading AIS, lake users are required to remove all aquatic plants or animals from their watercraft and drain all water from their boat before leaving the access. If you suspect an infestation of an invasive species in this lake, save a specimen and report it to a local natural resource office. Additional information on all of these topics can be found on the DNR website (www.dnr.state.mn.us) or by contacting the Walker Area Fisheries office.

A targeted survey of nearshore fish species in Mule Lake was conducted on July 11-13, 2022, by DNR 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 13 sampling stations, but one station was sampled from the boat due dense submerged vegetation and water lilies. Similarly, a 50-foot seine was used to sample five stations, a 15-foot seine was used at six stations, two stations were sampled from the boat due to steep shorelines (one with a 15-foot and one with a 50-foot seine), and dense vegetation prevented the use of seines at one station. Nearshore sampling captured 15 species of fish including four species that are intolerant of disturbance (i.e., Iowa Darter, Mimic Shiner, Rock Bass, and Smallmouth Bass) and one that is tolerant of disturbance (i.e., Fathead Minnow). A summer trap net survey was also conducted by IBI Program staff on July 11-14, 2022. Nine trap nets were set along the shoreline in locations that encompassed multiple habitat types. Trap net sampling captured eight species of fish, none that are tolerant of disturbance. Bluegill comprised a majority of the catch by number and biomass. The nearshore and trap net were combined with gill net data from a 2018 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., Mimic Shiner, Rock Bass, Smallmouth Bass, and Iowa Darter), while other species are tolerant of degraded conditions (e.g., Fathead Minnow). 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. Results from this survey indicate that the fish community in Mule Lake is healthy as indicated by an FIBI score that is well above the impairment threshold determined for similar lakes. Data from this survey will contribute biological information about the health of the fish community to the Leech Lake River Watershed assessment process in coordination with MN Pollution Control Agency.

A targeted survey of nearshore fish species in Mule Lake was conducted on August 8, 2018 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 seine, where possible. Backpack electrofishing was completed at 14 sampling stations, but three stations were sampled from the boat due to site conditions. Similarly, a 50-foot seine was used to sample 11 stations, and site conditions prevented the use of seines at three stations. Nearshore sampling captured 16 species of fish including five species that are intolerant of disturbance (Blackchin Shiner, Iowa Darter, Mimic Shiner, Rock Bass, and Smallmouth Bass) and one that is tolerant of disturbance (Fathead Minnow). The nearshore data were combined with trap net and gill net data from a June 2018 standard 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. Fathead Minnow). 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. Data from this survey indicates Mule Lake is in exceptional health as indicated by an FIBI score well above the impairment threshold for aquatic life use determined for similar lakes. Data from this survey will contribute biological information about the health of the fish community to the Leech Lake River Watershed assessment process in coordination with MN Pollution Control Agency.

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

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

Mule has a maximum depth of 47 feet, per Minnesota DNR data.

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

No invasive species are on record for Mule in Minnesota DNR data. Always clean, drain, and dry your equipment to help keep it that way.