Mountain

Mountain Lake is a 241-acre, class 43 lake, located within the City of Mountain Lake in Cottonwood County. The lake has a maximum depth of 7.0 feet, and has a watershed-to-lake ratio of 22-to-1. In the early 1990's, Mountain Lake had a diverse population of fish. During the winter of 1993-94, the lake suffered a partial winterkill, resulting in an increase in Common Carp and Black Bullhead abundance, which resulted in a decrease in aquatic vegetation. Because of the high abundance of undesirable fish, Mountain Lake Watershed was reclaimed during the fall of 1998, with the goal to restore desirable fish populations, re-establish aquatic vegetation, and improve water quality. Curlyleaf Pondweed is abundant in Mountain Lake, to the extent that a vegetation harvester is operated by the City of Mountain Lake on an annual basis. Mountain Lake is managed primarily for Largemouth Bass and Bluegill, and secondarily for Yellow Perch, Walleye, Northern Pike, and Black Crappie. A daytime electrofishing survey was conducted in the week of May 6, 2025 to monitor the Largemouth Bass population and the newly introduced Yellow Bass population. Largemouth Bass electrofishing catch rates have been highly variable, ranging from 0.0 per hour in 1994 to 228.0 per hour in 2000, and averaging 73.9 per hour since 1994. In 2025, the Largemouth Bass catch rate was 78.5 per hour. Multiple year classes of Largemouth Bass were present as lengths ranged from 6.2 to 19.2 inches and averaged 15.7 inches. Management goals were met because the catch rate exceeded the goal of 20.0 per hour and size structure indices were within desired ranges. It appears that the Largemouth Bass population in Mountain Lake is a stable, naturally reproducing population with many fish 15 to 20 inches present. Prior to the electrofishing survey, it was reported that Yellow Bass had been caught by anglers at Mountain Lake. During sampling, Yellow Bass were captured at a rate of 29.7 per hour and ranged in length from 8.0 to 11.7 inches and averaged 8.8 inches. Once introduced, Yellow Bass tends to establish and maintain a robust population. Yellow Bass are native to Minnesota but historically had only been documented in the Mississippi River. Windom Area Fisheries first sampled Yellow Bass in Hall Lake in Martin County in 2013, and since have seen rapid expansion of populations to various water bodies in Martin, Cottonwood, Jackson, and Faribault Counties, likely a result of illegal stocking by anglers.

A targeted survey of the nearshore fish community in Mountain Lake was conducted by Fisheries Index of Biological Integrity (IBI) Program Staff from 20-21 June 2023. Ten sampling sites were evenly spaced around the lake and each was sampled by backpack electrofishing and seining with a 15-foot or 50-foot seine, where possible. Backpack electrofishing was completed at all 10 sites. A 50-foot seine was used to sample seven sites, a 15-foot seine was used at two sites, and soft sediments with abundant vegetation and deep water prevented the use of seines at one sampling site. Nearshore sampling captured 10 species of fish including three species (Black Bullhead, Common Carp and Fathead Minnow) that are tolerant of disturbance. The nearshore data were combined with trap net and gill net data from a May-June 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. Data from this survey indicates the fish community in Mountain Lake is adversely impacted by stressors as indicated by an FIBI score below the impairment threshold for aquatic life use determined for similar lakes. These results are similar to previous findings, which indicated that Mountain Lake was impaired for aquatic life use based on the Fish IBI. Data from this survey will contribute biological information about the health of the fish community to Watonwan River Watershed assessment process in coordination with MN Pollution Control Agency.

Mountain Lake is a 241-acre lake, located within the City of Mountain Lake in Cottonwood County. The lake has a maximum depth of 7.0 feet, and has a watershed-to-lake ratio of 22-to-1. In the early 1990's, Mountain Lake had a diverse fish population. During the winter of 1993-94, the lake suffered a partial winterkill, resulting in an increase in Common Carp and Black Bullhead abundance and a decline in aquatic vegetation. Because of the high abundance of undesirable fish, Mountain Lake Watershed was reclaimed during the fall of 1998, with the goal to restore desirable fish populations, re-establish aquatic vegetation, and improve water quality. Since the restoration, aquatic vegetation is abundant in Mountain Lake, to the extent that a vegetation harvester is operated by the City of Mountain Lake on an annual basis. Mountain Lake is managed primarily for Largemouth Bass and Bluegill, and secondarily for Yellow Perch, Walleye, Northern Pike, and Black Crappie. A standard survey was conducted the week of May 31, 2022 to monitor fish populations using one gill net and nine trap nets. Largemouth Bass electrofishing catch rates have been highly variable, ranging from 0.0 per hour in 1994 to 228.0 per hour in 2000, and averaging 64.8 per hour since 1994. In 2022, the Largemouth Bass catch rate was 33.0 per hour. Multiple year classes of Largemouth Bass were present as lengths ranged from 4.9 to 16.6 inches and averaged 9.9 inches. Largemouth Bass in the sample were plump and feeding successfully. Management goals were met because the catch rate exceeded the goal of 20.0 per hour and size structure indices were with in desired ranges. It appears that the Largemouth Bass population in Mountain Lake is a stable, naturally reproducing population. The Bluegill catch rate in 2022 was 57.8 per trap net, an increase from 20.7 per trap net in 2018 and exceeded the expected range of catch rates for similar lakes (1.2 to 20.0 per trap net). Bluegill abundance has been highly variable at Mountain Lake with catch rates varying from 0.1 per trap net in 1997 to 172.2 per trap net in 2002, averaging 38.6 per trap net since 1985. Lengths of Bluegill ranged from 4.1 to 8.2 inches and averaged 6.5 inches. Size structure of Bluegill appears to have slightly increased since 2018 as a few Bluegill over 7.9 inches were sampled in 2022, which were not sampled in 2018. Bluegill should be reaching a harvestable size in Mountain Lake. The 2022 Walleye catch rate was 14.0 per gill net, which is the second highest catch rate observed on Mountain Lake and is within the expected range of catch rates for similar lakes (2.3 to 18.1 per gill net). Historically, catch rates have ranged from 0.0 per gill net in 1994 to 21.0 per gill net in 2014 and have averaged 6.7 per gill net since 1985. Walleye lengths ranged from 12.1 to 24.0 inches, averaging 17.5 inches. Mountain Lake is stocked with yearling and adult Walleye, when available because it has abundant aquatic vegetation and relatively clear water, which Walleye fry and fingerlings are difficult to establish in those habitat scenarios. Stocking yearling and adult Walleye provides anglers the opportunity to catch a Walleye in a lake that is best suited for Largemouth Bass and Bluegill populations. Only one 36.0 inch Northern Pike was sampled in the 2022 survey, a decrease in the catch rate from 6.0 per gill net in 2018 to 1.0 per gill net in 2022. Northern pike are a secondary management species in Mountain Lake and are difficult to produce consistently in the Windom Area, thus Northern Pike are stocked sporadically if fish are available. The most recent stockings occurred in 2016 (1,688 fingerlings and 188 adults) and 2022 (680 fall fingerlings). None-the-less anglers have the opportunity to catch pike in Mountain Lake. Mountain Lake is within the "southern zone" of the Northern Pike zone regulations, so two Pike longer than 24 inches can be harvested. Northern Pike under 24 inches must be released. The Black Crappie catch rates increased from 2.0 per gill net in 2018 to 23.0 per gill net in 2022, which is higher than the expected range of catch rates for similar lakes (1.4 per gill to 14.8 per gill net). Lengths of Black Crappie ranged from 2.2 inches to 11.8 inches and averaged 8.1 inches. Black Crappie populations can be cyclical, where years of low catch rates are followed by years of higher catch rates, and it appears that the Mountain Lake Black Crappie population may be trending towards the high point of the cycle. The 2022 Yellow Perch catch rate was 13.0 per gill net, the same as the 2018 catch rate and was within the expected range of catch rates for similar lakes (2.7 to 25.0 per gill net). Yellow Perch lengths ranged from 7.3 inches to 11.4 inches and averaged 8.6 inches. Other species sampled included Black Bullhead, Common Carp, Pumpkinseed, and Yellow Bullhead.

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

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

Mountain has a maximum depth of 8 feet, per Minnesota DNR data.

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

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