Sucker

Temperature and dissolved oxygen measurements were collected from the deepest basin in Sucker Lake on August 7th, 2025. This was done 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. 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 data collected from the deepest basin (maximum sampled depth was 29.5 feet), the water temperature decreased to 21.2 degrees C (70.2 degrees F) at 17.3 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 21.2 feet at the time of sampling. This layer in the water column was 3.9 feet, indicating oxythermal habitat for Cisco was present. Further, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was 14.2 degrees C (57.6 degrees F). TDO3 values cooler than 21.2 degrees C (70.2 degrees F) indicate that oxythermal conditions were suitable for Cisco at the time of the survey. Data collected by the Minnesota Department of Natural Resources during the period of maximum oxythermal stress (July 26th to Aug 24th) in 2018 and 2024 also indicated suitable oxythermal habitat in all years surveyed, with the least favorable conditions recorded in 2024 when the suitable oxythermal habitat layer was 1.4 feet thick. When adequate oxythermal habitat is not available, Cisco are squeezed into unfavorable, warmer water conditions and experience higher levels of stress. On Sucker Lake, when adequate oxythermal habitat is not available, fish can move out of the lake into Newfound Lake and then into Moose Lake which contains better oxythermal conditions for Cisco.

Sucker Lake is a 393-acre lake located 21 miles northeast of Ely. There are five accesses; two are water routes and three are portages. The two water routes consist of a connection to Newfound Lake on the south end and a connection to Birch Lake on the north end. The most prominent portage is Prairie Portage, a motor portage on the U.S. side of the lake where a truck concessionaire will bring motorboats back and forth to Basswood Lake. The other portages include a 20-rod portage on the Canadian side of Sucker Lake into Basswood and a 6-rod portage on the northeast side connecting to Birch Lake. Although Sucker Lake is located in the Boundary Waters Canoe Area Wilderness (BWCAW) within the Superior National Forest, outboard motors up to 25 hp are allowed. There are eight U.S. Forest Service maintained campsites and visitors need to have appropriate permits, issued by the U.S. Forest Service, to visit the lake. The lake has a maximum depth of 31 feet and at the time of the survey, light green colored water. Sucker was thermally stratified on August 5, 2024, with a surface temperature of 74 F and a bottom temperature of 53 F. Oxygen levels were adequate for gamefish to a depth of 20 feet. Sucker Lake receives water from Newfound Lake to the south and Birch Lake to the northeast. The outlet flows over a fixed sill dam on the lake's northwest side on its way to Basswood Lake. Lake bottom substrates along the shoreline are mostly ledge rock, rubble, and gravel. Aquatic vegetation is very sparse. The overall gillnet catch rate for all fish combined was 21.8 fish/net which was below average for the lake. Fish species sampled in gillnets were cisco, walleye, white sucker, rock bass, northern pike, bluegill, largemouth bass, smallmouth bass, and yellow perch. The overall trap net catch rate for all fish combined was 4.7 fish/net which was just below average for the lake. Fish species sampled in trap nets were rock bass, northern pike, smallmouth bass, bluegill, yellow perch, black crappie, hybrid sunfish, and walleye. The 2024 gill nets sampled 56 walleye for a catch rate of 6.2 fish/net. This catch rate was below average for Sucker Lake but better than average for Tower area lakes overall. Lengths ranged from 9 to over 28 inches with an average of over 15 inches. Growth was extremely fast with a 4-year-old walleye averaging 16 inches. Fish were aged up to 13 years old with evidence of consistent natural reproduction. The northern pike gill net catch rate of 1.2 fish/net was below average for Sucker. Lengths ranged from 16 to 28 inches with an average of 23 inches. The average and max lengths were both relatively small for Sucker Lake. Smallmouth bass were sampled in relatively low numbers in both gillnets and trap nets. Catch rates in both net types were below average for the lake. Lengths ranged from over 5 inches to 14 inches with an average size of almost 9 inches, which was also lower than is typical for Sucker Lake. The cisco gillnet catch rate was 8.6 fish/net which was the lowest on record for surveys on Sucker Lake. Lengths ranged from 7 to 16 inches with an average of 12 inches. While numbers appeared to be down in 2024, both the average and maximum size were the largest on record for the lake. The bluegill trap net catch rate of 0.6 fish/net was above average for the lake. Lengths ranged from 6 to over 7 inches with an average length of 7 inches, the largest average size of any survey on the lake. Trap nets also sampled black crappie for the first time ever in 2024. However, these fish averaged just over 4 inches in length. Rusty crayfish are a non-native invasive species that were first sampled in 1989 in Sucker Lake. They were likely first introduced to the Moose Chain of Lakes in anglers' bait buckets. In 2024, the rusty crayfish catch rate was 31.8 crayfish/gillnet. This catch rate was below average compared to past surveys.

Sucker Lake is a 393 acre lake located 21 miles northeast of Ely. There are five accesses, two of which are water routes, and three portages. The two water routes consist of a connection to Newfound Lake on the south end and a connection to Birch Lake on the north end. The three portages consist of Prairie Portage (a motor portage on the U.S. side of the lake, where a truck concessionaire will bring motor boats back and forth to Basswood Lake), a 20 rod portage on the Canadian side also connecting to Basswood Lake, and a 6 rod portage on the northeast side connecting to the aforementioned Birch Lake. Although Sucker Lake is located in the Boundary Waters Canoe Area Wilderness (BWCAW) within the Superior National Forest, outboard motors up to 25 hp are allowed. There are eight U.S. Forest Service maintained campsites and visitors need to have appropriate permits, issued by the U.S. Forest Service, to visit the lake. The lake has a maximum depth of 31 feet and at the time of the survey, light green colored water. Sucker was thermally stratified on August 13, 2018 with a surface temperature of 77 F and a bottom temperature of 48 F. Oxygen levels were adequate for gamefish to a depth of 24 feet. Sucker Lake receives water from Newfound Lake to the south and Birch Lake to the northeast. The outlet flows over a fixed sill dam on the lake's northwest side on its way to Basswood Lake. Lake bottom substrates along the shoreline are mostly ledge rock, rubble, and gravel. Aquatic vegetation is very sparse. There is no stocking currently being done on Sucker Lake. The overall gillnet catch rate for all fish combined was 51.9 fish/net which was higher than average for the lake. Fish species sampled were cisco, walleye, white sucker, northern pike, yellow perch, rock bass, and smallmouth bass. The 2018 gill nets sampled 84 walleye for a catch rate of 9.3 fish/net. This catch rate was the second highest on record for Sucker and higher than average compared to other similar lakes. The catch rate was also quite good for Tower area lakes overall. Lengths ranged from 9 to 28 inches with an average of 14 inches. The average walleye weighed nearly a pound and a half, which was good compared to other similar lakes. Growth was extremely fast with a 4 year old walleye averaging nearly 18 inches. Fish were aged up to 17 years old with strong year classes in 2009 and 2016. The northern pike gill net catch rate of 2.9 fish/net was the highest on record for Sucker Lake and better than average compared to other similar lakes. Lengths ranged from 22 to 40 inches with an average of 28 inches. The average and max lengths were both very good for Sucker Lake. The average weight was just over 5 pounds which was quite high compared to other similar lakes throughout the state as well as within the area. The cisco gillnet catch rate was 32 fish/net which was above average for surveys on Sucker Lake and quite high when compared to other cisco lakes in the area. Lengths ranged from 7 to 15 inches with an average of 11 inches. Smallmouth bass, yellow perch, white sucker, and rock bass were also sampled in gill nets. Their catch rates and sizes were similar to past surveys. Rusty crayfish are a non-native invasive species that were first sampled in 1989 in Sucker Lake. They were likely first introduced to the Moose Chain of Lakes in anglers' bait buckets. In 2018, the rusty crayfish catch rate was 86.2/net. This catch rate is similar to past surveys.

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

We don't have a confirmed public access point on record for Sucker. Check the DNR LakeFinder page for current access details before you go.

Sucker has a maximum depth of 31 feet, per Minnesota DNR data.

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

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