Spirit

A temperature-dissolved oxygen (TDO) profile was collected on 8/5/2025, to measure the amount of thermal habitat available for Tullibee. The TDO3 (temperature at 3 mg/l dissolved oxygen) was determined to be 20.7 degrees C. Limited oxy-thermal habitat was available throughout the water column with adequate conditions occurring from the surface to a depth of 19 feet. Comparing profiles collected from 2011-2025, the best conditions for Tullibee occurred in 2013, 2015, 2017, 2019, 2023 and 2025, although these conditions were still only marginal compared to other lakes in the area that are monitored. Because the Aitkin management area is located near the southern edge of Minnesota's Tullibee range, TDO profiles should continue to be collected to monitor the availability of cold-water habitat.

A targeted survey of nearshore fish species in Spirit Lake was conducted beginning on June 30, 2025, by Lake Biological Monitoring and Assessment (LBMA) 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 14 sampling stations. Similarly, a 50-foot seine was used to sample 12 stations. Two stations were not seined due to dense vegetation and soft substrate. Nearshore sampling captured 25 species of fish including 10 species that are intolerant of disturbance (i.e., Banded Killifish, Blackchin Shiner, Blacknose Shiner, Iowa Darter, Logperch, Mimic Shiner, Mottled Sculpin, Pugnose Shiner, Rock Bass, and Smallmouth Bass) and none that are tolerant of disturbance. A concurrent summer trap net survey was also conducted by LBMA Program staff. Twelve trap nets were set along the shoreline in locations that encompassed multiple habitat types. Trap net sampling captured 11 species of fish, including one that is intolerant of disturbance (i.e., Rock Bass) and one that is tolerant of disturbance (i.e., Black Bullhead). Bluegill comprised a majority of the catch by number and biomass. The nearshore and trap net data were combined with gill net data from a survey conducted during the week of July 17, 2023 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 healthy habitat (e.g., Blackchin Shiner, Iowa Darter, and Rock Bass), while other species are tolerant of degraded conditions (e.g., Black Bullhead, Green Sunfish, and Common Carp). 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 Spirit Lake is healthy as indicated by an FIBI score that exceeds the exceptional aquatic life use threshold determined for similar lakes. These results are similar to previous findings, which indicated that Spirit Lake is fully supporting aquatic life use. The survey results will be considered when the biological health of the lake is assessed during the Mississippi River-Brainerd assessment process, which will be completed in coordination with MN Pollution Control Agency. You can help protect the fish community in Spirit Lake by reducing runoff, maintaining natural shorelines, and preventing the spread of invasive species.

A temperature - dissolved oxygen (TDO) profile was collected on August 6, 2024, to measure the amount of thermal habitat available for Tullibee. The TDO3 (temperature at 3 mg/l dissolved oxygen) was determined to be 21 degrees C. Limited oxy-thermal habitat was available throughout the water column with only a couple of TDO points falling inside the suitable curve. Comparing profiles collected from 2011-2024, the best conditions for Tullibee occurred in 2013, 2015, 2017, 2019 and 2023, although still only marginal compared to other lakes in the area that are monitored. Because the Aitkin area is located near the southern edge of Minnesota's Tullibee range, TDO profiles should continue to be collected to monitor the availability of cold-water habitat.

Based on Minnesota DNR survey data, anglers target Largemouth Bass, Rock Bass, Hybrid Sunfish, Walleye, and Yellow Perch in Spirit. See the full species list above for catch rates, size structure, and quality scores.

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

Spirit has a maximum depth of 49 feet and a mean depth of 15 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Spirit is from 2025.

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