Little Thunder

A targeted survey of nearshore fish species in Little Thunder Lake was conducted beginning on August 11, 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 10 sampling stations. Similarly, a 50-foot seine was used to sample seven stations, and a 15-foot seine was used at one station. Two stations were electrofished from the boat and not seined because they were located along a bog or cattail fringe. Nearshore sampling captured 16 species of fish including 6 species that are intolerant of disturbance (i.e., Banded Killifish, Blackchin Shiner, Blacknose Shiner, Iowa Darter, Least Darter, Northern Sunfish) and none that are tolerant of disturbance. A concurrent summer trap net survey was also conducted by LBMA Program staff. Eight trap nets were set along the shoreline in locations that encompassed multiple habitat types. Trap net sampling captured 10 species of fish, including one that is intolerant of disturbance (i.e., Rock Bass) and none that are tolerant of disturbance. Bluegill comprised a majority of the catch by number and whereas Bowfin comprised a majority by biomass. The nearshore and trap net data were combined with gill net data from a survey conducted during the week of June 10, 2024 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., 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 Little Thunder Lake is healthy as indicated by an FIBI score that exceeds the exceptional aquatic life use threshold determined for similar lakes. The FIBI results are similar to previous findings, which indicated that Little Thunder 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-Grand Rapids Watershed assessment process, which will be completed in coordination with MN Pollution Control Agency. You can help protect the fish community in Little Thunder Lake by reducing runoff, maintaining natural shorelines, and preventing the spread of invasive species.

A targeted survey of nearshore fish species in Little Thunder Lake was conducted on June 17, 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 ten sampling stations. Similarly, a 50-foot seine was used to sample five stations, and a 15-foot seine was used at three stations. Two stations were not seined because they were located along a bog or cattail fringe. Nearshore sampling captured nineteen species of fish including eight species that are intolerant of disturbance (i.e., Banded Killifish, Blackchin Shiner, Blacknose Shiner, Iowa Darter, Least Darter, Mimic Shiner, Northern Sunfish, Rock Bass) and none that are tolerant of disturbance. A summer trap net and gill net survey was also conducted on June 10-12, 2024, by IBI Program staff. Eight trap nets were set along the shoreline in locations that encompassed multiple habitat types. Trap net sampling captured seven species of fish, including one that is intolerant of disturbance (i.e., Rock Bass). Bluegill comprised a majority of the catch by number, whereas Bowfin comprised a majority by biomass. Six gill nets were set in deeper locations that encompassed multiple habitat types. Gill net sampling captured seven species of fish, including two that are intolerant of disturbance (i.e., Cisco and Rock Bass). Northern Pike and Yellow Perch comprised a majority of the catch by number, whereas Northern Pike and Cisco comprised a majority by biomass. The nearshore, trap net, and gill net data were combined 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., 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. In addition to fish sampling, IBI Program staff also conducted an assessment of lakeshore habitat on Little Thunder Lake on June 10, 2024, following the Score the Shore survey protocols. The assessment consisted of 50 survey sites evenly spaced every 200 meters around the lake. Assessments were made in three habitat zones: the shoreline zone (i.e., the shore-water interface to the top of the natural bank), the shoreland zone (i.e., land-ward from the shoreline to developed structure or 100 feet), and the aquatic zone (i.e., lake-ward 50 feet from the shoreline). The average lakewide habitat score was 81.4 (+/- 2.5) out of 100 possible. A score of 81.4 indicates the lakewide shoreline condition is moderately high (i.e., 80-84.9). Approximately 28 percent of the sites were developed, with a mean score of 60.1 (+/- 5.5) indicating shoreline habitat quality of developed sites is poor (i.e., 50-65.9), while undeveloped sites had a mean score of 89.6 (+/- 0.8) with high (i.e., 85-91.9) habitat quality. Results from this survey provide evidence that the fish community and lakeshore habitat in Little Thunder Lake are healthy as indicated by an FIBI score that exceeds the exceptional use threshold determined for similar lakes and a moderately high habitat score. The FIBI results are similar to previous findings, which indicated that Little Thunder Lake is fully supporting aquatic life. The survey results will be considered when the biological health of the lake is assessed during the Mississippi River-Grand Rapids Watershed assessment process, which will be completed in coordination with MN Pollution Control Agency. You can help protect the fish community in Little Thunder Lake by reducing runoff, maintaining natural shorelines, and preventing the spread of invasive species.

A special IBI assessment was conducted on Little Thunder Lake to sample the nearshore fish community. Backpack electrofishing gear along with seining equipment was used at 10 sites around the lake. The most common species captured was bluegill. Other notable species caught included longear sunfish, blackchin shiner, and 11 other species of fish.

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

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

Little Thunder has a maximum depth of 72 feet and a mean depth of 29 feet, per Minnesota DNR data.

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

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