Andrusia

Temperature and dissolved oxygen measurements were collected from the deepest basin in Lake Andrusia, which is located wholly within the Leech Lake Reservation, on August 5th, 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 Leech Lake Band of Ojibwe (LLBO) holds Clean Water Act jurisdiction over waters within the exterior boundaries of the Leech Lake Reservation, which allows LLBO to establish water quality standards to protect Reservation waters and culturally important aquatic resources. 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. Based on data collected from the deepest basin (maximum sampled depth was 62.3 feet), the water temperature decreased to 21.2 degrees C (70.2 degrees F) at 28.9 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 25.8 feet at the time of sampling. Therefore, the water column did not contain a layer of water with sufficient temperature and dissolved oxygen for Cisco. Data collected by the Minnesota Department of Natural Resources during the late summer period of maximum oxythermal stress (July 26th to August 24th) in 2006 and 2024 also indicate unsuitable oxythermal habitat for Cisco, with the least favorable conditions recorded in 2006. However, a survey completed in 2009 did indicate marginal habitat for Cisco, with a TDO3 of 18.9 degrees C. This variation indicates that coldwater habitat is marginal on Lake Andrusia. 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 Andrusia Lake, which is located within the Leech Lake Nation, was conducted beginning on July 17th, 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 18 sampling stations. Similarly, a 50-foot seine was used to sample 12 stations, and a 15-foot seine was used at 5 stations. One station was not seined due to soft substrate and dense wild rice. Nearshore sampling captured 28 species of fish including 9 species that are intolerant of disturbance (e.g., Blackchin Shiner and Mimic Shiner) and 3 that are tolerant of disturbance (Green Sunfish, Fathead Minnow, and Black Bullhead). A concurrent summer trap net survey was also conducted by IBI Program staff. Twelve trap nets were set along the shoreline in locations that encompassed multiple habitat types. Trap net sampling captured 14 species of fish, including 3 that are intolerant of disturbance (i.e., Cisco (Tullibee), Greater Redhorse, and Rock Bass). Yellow Perch, Bluegill, and Bowfin comprised a majority of the catch by number, whereas Bowfin, Walleye, and Northern Pike comprised a majority by biomass. The trap net catch was light overall. Temperature and dissolved oxygen (DO) measurements were collected from the deepest basin in Andrusia Lake, on August 7th, 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 (maximum sampled depth 55.8 feet), the water temperature decreased below 21.2 degrees C (70.2 degrees F) at 28.5 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 28.0 feet at the time of sampling. Therefore, the water column did not contain a layer of water with sufficient temperature and dissolved oxygen 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 21.6 degrees C (70.9 degrees F). TDO3 values warmer than 21.2 degrees C (70.2 degrees F) indicate that oxythermal conditions were unsuitable for Cisco 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 Aug 24th) in 2006 and 2009 indicate unsuitable oxythermal habitat in most years when surveyed, with the least favorable conditions recorded in 2006 when there was no suitable oxythermal habitat layer observed. When inadequate oxythermal habitat is available, Cisco are squeezed into unfavorable, warmer water conditions and experience higher levels of stress. The nearshore and trap net data were combined with gill net data from a July 2019 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, Cisco (Tullibee), and Rock Bass), while other species are tolerant of degraded conditions (e.g., Green Sunfish and 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 provide evidence that the fish community in Andrusia Lake is healthy as indicated by an FIBI score above the general use impairment threshold for aquatic life use determined for similar lakes. These results are similar to previous findings regarding the biological health of Andrusia Lake. You can help protect the fish community in Andrusia Lake by reducing runoff, maintaining natural shorelines, and preventing the spread of invasive species. A survey of lakeshore habitat on Andrusia Lake following the Score the Shore survey protocols was conducted on Aug 22, 2019. The survey consisted of 83 survey sites evenly spaced 200 meters around the lake. Assessments were made in three habitat zones: Shoreline Zone (the shore-water interface to the top of the natural bank), Shoreland Zone (land-ward from shoreline to development structure or 100 feet), and Aquatic Zone (lake-ward 50 feet of shoreline). The average lakewide habitat score was 78.6 out of 100 possible. A score of 78.6 indicates the lakewide shoreline condition is Moderate (70-80).

Andrusia is a 1,590-acre lake, located 10 miles east of Bemidji, MN and within the Cass Lake chain of lakes. A targeted survey was completed on Lake Andrusia by Bemidji Area Fisheries staff during late July in 2019 to assess the nearshore fish community and overall health of the lake. In this survey, 18 nearshore sites (100-foot) were evenly spaced along the lakeshore to sample a variety of aquatic habitat types and collect a representative sample of the nearshore fish community. Depending on the habitat conditions at each site, backpack electrofishing and shoreline seining were attempted where possible. A total of 10 sites were sampled with a seine, while backpack electrofishing was completed at all 18 sites. A total of 26 species of fish were sampled, which included nine species (Banded Killifish, Blackchin Shiner, Cisco, Logperch, Mimic Shiner, Mottled Sculpin, Muskellunge, Pugnose Shiner, and Rock Bass) that are intolerant to disturbance or poor water quality. Nearshore fish community data was analyzed with information collected from standard survey completed in 2019 to calculate a Fish-based Index of Biologic Integrity (FIBI) score to measure the biological condition and overall health of Lake Andrusia. In Minnesota lakes, certain fish species cannot survive without clean water and healthy habitat (e.g. Blackchin Shiner, Least Darter, and Rock Bass), while other species are tolerant of degraded conditions (e.g. Black Bullhead, Fathead Minnow, and Green Sunfish). The combination of fish species present may identify stressors negatively affecting the lake environment. The FIBI score is composed of several fish community diversity and composition metrics to indicate the overall health of a lake by comparing it to what is expected for a healthy lake. For additional information on FIBI, search for "lake index of biological integrity" on the Minnesota Department of Natural Resources website (www.mndnr.gov). According to the survey, Andrusia Lake is in good health with a FIBI score above the impairment and exceptional thresholds for aquatic life use determined for similar lakes. In coordination with the Minnesota Pollution Control Agency, data from this survey will contribute biological information about the health of the fish community to the Mississippi River (Headwaters) Watershed assessment.

Based on Minnesota DNR survey data, anglers target Northern Pike, Muskellunge, Walleye, Rock Bass, and Yellow Perch in Andrusia. See the full species list above for catch rates, size structure, and quality scores.

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

Andrusia has a maximum depth of 60 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Andrusia is from 2024.

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