Lower (South) Island

A targeted survey of nearshore fish species in Lower (South) Island Lake was conducted on July 8th, 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, where possible. Backpack electrofishing was completed at all ten sampling stations, but one station was sampled from the boat due to site conditions. Similarly, a 50-foot seine was used to sample three stations, a 15-foot seine was used at four stations, and site conditions prevented the use of seines at three stations. Nearshore sampling captured 14 species of fish including three species that are intolerant of disturbance (i.e., Iowa Darter, Mottled Sculpin, and Rock Bass) and no species that are tolerant of disturbance. A concurrent summer trap net survey was conducted on July 8th, 2024 by IBI Program Staff. Nine trap nets were set along the shoreline and in shallow offshore locations that encompassed multiple habitat types. Bluegill, Yellow Bullhead, and Pumpkinseed comprised a majority of the trap net catch by number, and Bowfin, Northern Pike, and Bluegill comprised a majority of the catch by biomass. The number of Bluegill and Black Crappie sampled per net were above the 25% quartile for similar Lake Class 29 lakes. Additionally, the mean weights of Bluegill and Black Crappie sampled per net were above the 50% quartile for Lake Class 29 lakes. The nearshore and trap net data were combined with gill net data from a July 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 a healthy habitat (e.g., Iowa Darter, Mottled Sculpin, 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. An additional survey was completed on Lower (South) Island Lake in June 2023 resulting in a similar FIBI score. For additional information on the FIBI, search for "lake index of biological integrity" on the mndnr.gov website. Data from this survey will contribute biological information about the health of the fish community to the Mississippi River - Grand Rapids Watershed assessment process in coordination with MN Pollution Control Agency.

Lower Island is a 320-acre lake with 207 (65%) acres of littoral area and a maximum depth of 22 feet. The lake is located just east of Cromwell, Minnesota off Highway #210. The lake has a DNR administered, gravel, back-in access located on the southeast shore. Lower Island was last surveyed in 2013. Lower Island was sampled in 2023 to help evaluate the walleye stocking program as well as update information on other fish populations. Lower Island has been actively managed by stocking Walleye fry, fingerling and yearling between 1948 and 1993, followed by fry stocking in even years from 1994 through 2022. Walleye abundance of 1.7 per gillnet lift was average compared to other Minnesota lakes of similar type. Walleye gillnet catch rates from seven investigations since 1972 have ranged from 1.7 to 8.7 per lift. Mean size of 17.5 inches for Walleye sampled in 2023 and the rate of growth was considered average. Eighty percent of Walleye that were sampled in 2023 were aged to years with fry stocking. Walleye aging from previous investigations resulted in correlations to years of stocking which ranged from 57% to 97%. Black Crappie abundance of 0.8 per trapnet lift was average compared to other Minnesota lakes of similar type. Average size was 8.8 inches and rate of growth was average. All year-classes from 2017 through 2021 were represented. Bluegill abundance of 16.1 per trapnet lift had decreased since 2013 (20.6) but was still considered average compared to other Minnesota lakes of similar type. Average size was 6.1 inches and growth was average compared to other Duluth Area lakes. Age analysis revealed consistent recruitment with all year-classes from 2014 through 2021 represented. Largemouth Bass abundance of 20.7 per hour of electrofishing was average compared to other Duluth Area lakes. Previous Largemouth Bass electrofishing assessments on Lower Island have ranged from 8.7 (2002) to 36.0 (2013) per hour of electrofishing. Average size of 11.2 inches was average and growth was fast compared to other Duluth Area lakes. Age analysis revealed a potentially strong 2021 year-class. All year-classes from 2015 through 2022 were observed except for 2019 and 2020. Northern Pike abundance of 8.3 per gillnet lift was average compared to other Minnesota lakes of similar type. Average size was 21.5 inches. Yellow Perch abundance was the same as in 2013 at 0.3 per lift and was below average compared to other Minnesota lakes of similar type. Other fish species sampled include Black Bullhead, Bowfin, Brown Bullhead, Hybrid Sunfish, Pumpkinseed, Rock Bass, White Sucker and Yellow Bullhead.

A targeted survey of nearshore fish species in Lower Island Lake was conducted on June 28, 2024 by DNR Fisheries 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 9 sampling stations, but 1 station was sampled from the boat due to site conditions. Similarly, a 50-foot seine was used to sample 3 stations, a 15-foot seine was used at 4 stations, and site conditions prevented the use of seines at 3 stations. Nearshore sampling captured 11 species of fish including 2 species that are intolerant of disturbance (Blackchin Shiner, Rock Bass) and 1 that is tolerant of disturbance (Black Bullhead). The nearshore data were combined with trap net and gill net data from a 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, Rock Bass), while other species are tolerant of degraded conditions (e.g., Black Bullhead, Common Carp, 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 will contribute biological information about the health of the fish community to the Mississippi-Grand Rapids Watershed assessment process in coordination with MN Pollution Control Agency.

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

Minnesota DNR records list public access for Lower (South) Island. Check the DNR LakeFinder page for the launch type and directions before you go.

Lower (South) Island has a maximum depth of 22 feet and a mean depth of 9 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Lower (South) Island is from 2024.

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