Little Trout

Little Trout is a 528-acre lake located 13 miles north of Tower in the Boundary Waters Canoe Area. It is comparable to Armstrong, Eagle's Nest Three, and Little Long lakes in the Tower Area. Little Trout was weakly thermally stratified during the survey with a surface temperature of 61 °F and a bottom temperature of 51 °F. Dissolved oxygen levels adequate for gamefish were present to 27 feet where the water temperature was 60 °F. Maximum depth is 37 feet. Secchi visibility was 6.5 feet, and the lake had a murky-brown tint. Aquatic vegetation is relatively abundant with extensive beds of pondweed and expansive bullrush beds. Access is primarily from the south through the channel to Trout Lake. Water levels and beaver activity may result in either an uninterrupted paddle upstream or several dam pullovers and shallow drags. A 141-rod portage to the north arm of Trout Lake, a 220-rod portage to Gowan Lake, and a 376-rod portage to the Little Indian Sioux River are also present. Three US Forest Service designated campsites dot the lake. The rolling landscape is a mosaic of old-growth pine and mixed deciduous forest interspersed with beaver drainages and bog fringe. A prescribed burn briefly reached the southeast end of the lake, and the eastern shore is a largely uninterrupted sand beach. Total catch in gill nets was the lowest surveyed from Little Trout. Unusually low numbers of yellow perch and modest cisco catch were driving factors. Walleye were the most common species sampled, followed by yellow perch, cisco, and bluegill. Northern pike were present in low numbers, with a smattering of golden shiner, largemouth bass, pumpkinseed, rock bass, smallmouth bass, and white sucker rounding out the catch. Walleye abundance (12.8/net) was the highest sampled to date and well above average for the lake. Walleye lengths ranged from 8.5 to 25 inches with a mean length of 15.5 inches which was higher than past surveys. Walleye aged with otoliths ranged from 1 to 14 years old. Fish from 11 year classes were present, but the catch was driven by exceptional 2021 and 2019 year classes. The 2017 year class was also standout despite eight years of mortality. Growth was close to the Area average, with age four fish reaching an average length of about 14 inches. Northern pike numbers (1.3/net) were lower than average for Little Trout but composed of larger than average fish. Lengths ranged from 19 to 35 inches with a mean length of 27 inches. Both mean and maximum length were the highest observed in a survey. Smallmouth bass were sampled at rate of 0.3/net. Lengths ranged from 5 to 18 inches, with an average length close to 11 inches. Largemouth bass were sampled for the first time in 2025 at a rate of 0.4/net. The largemouth bass were small, ranging from 9 to 11 inches and averaging just 10 inches in length. Both species are likely more abundant than surveyed, and gill nets are well understood to be an unreliable sampling gear for both species. Dozens of similarly small largemouth were observed by the survey crew near the outlet. Cisco numbers (8.2/net) were below average. Sizes continue to trend larger, ranging from 12.5 to nearly 17 inches with a mean length of 15 inches. Both mean and maximum length were the highest sampled in a survey. This shift from numerous small individuals to fewer larger fish is typical in warming lakes. Bluegill abundance (3.2/net) declined compared to the previous survey. Lengths ranged from 5 to 9 inches with a mean length of 7.5 inches. Fish greater than 8 inches made up 45% of the catch. Bluegill appear to have settled into a niche in Little Trout and may provide a bonus angling opportunity for those who discover them. Yellow perch numbers (9.3/net) were below average for Little Trout. In a common refrain, sizes trended larger and ranged from 4.5 to 10.5 inches with a mean of 7.5 inches. Mean and maximum length were both the highest sampled. Lower perch abundance is likely attributed to increased walleye abundance.

Temperature and dissolved oxygen measurements were collected from the deepest basin in Little Trout Lake on August 5th, 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 39.4 feet), the water temperature decreased to 21.2 degrees C (70.2 degrees F) at 15.0 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 15.7 feet at the time of sampling. This layer in the water column was 0.7 feet, indicating oxythermal habitat for Cisco was present but marginal. Further, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was 20.4 degrees C (68.7 degrees F). TDO3 values cooler than 21.2 degrees C (70.2 degrees F) indicate that oxythermal conditions were marginal for Cisco at the time of the survey as the layer was confined to less than 3 feet of suitable habitat 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 2023 indicate suitable oxythermal habitat with a suitable oxythermal habitat layer that was 4.3 feet thick. When inadequate oxythermal habitat is available, Cisco are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.

Little Trout Lake is located within the Boundary Waters Canoe Area Wilderness (BWCAW) within the Superior National Forest and is a non-motorized lake. It sits just east of the north arm of Trout Lake which is north of Lake Vermilion. It is accessed by three different portages and one water connection from Trout Lake, although beaver dams may be present. Little Trout is a 538 acre lake with a maximum depth of 37 feet and relatively clear water. Shorelines are made up of mostly sand with some rubble, gravel, ledgerock, and boulder. A total of nine different species were sampled: yellow perch (41%), walleye (15%), bluegill (15%), northern pike (12%), tullibee (11%), smallmouth bass (2%), white sucker (2%), pumpkinseed (1%), and rock bass (1%). The walleye catch rate of 7.4 fish/gill net was above the historic average of 6.6 fish/net. Average length was 16 inches and the largest walleye sampled was 26 inches. Growth was slow when compared to other lakes in the Tower Fisheries Management Area. The oldest walleye in the sample was 14 years old and 24 inches long. The northern pike catch rate of 5.9 fish/gill net was the highest catch rate on record for Little Trout Lake. Length ranged from 16 to 34 inches with an average of 23 inches. Growth was slightly better than the area average. Ages ranged from 2 to 8 years with 75% of the fish being age 4 or younger and generally under 24 inches long. Nine smallmouth bass were sampled for a catch rate of 1.0 fish/net which is close to average for this type of lake. Sizes were good as fish ranged from 14 to 19 inches with an average of 16 inches. Additionally the average weight was 2.5 lbs. All fish that were aged were found to be 7 years old. A good bluegill population was sampled for the first time ever on Little Trout Lake. The catch rate was 7.3 fish/net. Bluegill sizes were quite impressive, ranging from 4 to 10 inches with an average of 7 inches. The average was also 0.4 lb/fish. Of all the bluegill sampled, 24 (36%) were 9 inches or larger. Yellow Perch numbers have historically been high on Little Trout Lake although, sizes are somewhat small. In 2013 the catch rate was 20.0 fish/net and sizes ranged from 5 to 10 inches with an average of 7 inches. The tullibee numbers in Little Trout seem to be dropping with 2013 having the lowest catch rate on record at 5.7 fish/net. Sizes were decent though with an average length of 15 inches and average weight of 1.4 lbs/fish. Lengths ranged from 13 to 17 inches.

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

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

Little Trout has a maximum depth of 37 feet, per Minnesota DNR data.

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

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