Triangle

Triangle Lake is located 13 miles east of Ely. There are two "remote" public accesses. The most commonly used access is a 50 yard roller portage between the southern shore of Ojibway Lake and the northern shore of Triangle Lake. The portage is slightly uphill to Triangle but boats up to 16 feet long are able to be rolled over a series of rollers which are attached to two rails. The other access is on the southern shore and is a 160 rod portage to the North Kawishiwi River. This 300 acre lake contains no major inlets and only one outlet which is about 90 feet long and drops 4 feet in elevation to Ojibway Lake. Triangle Lake has a maximum depth of 45 feet and the water color was green at the time of the survey with a slight algae bloom. On July 20, 2020 Triangle was thermally stratified with a surface temperature of 73F and a bottom temperature of 44 F. Oxygen levels were adequate for gamefish to a depth of 19 feet where the water temperature was 59 F. Lake bottom substrates along the shoreline of Triangle Lake are mostly boulder, rubble, gravel, and ledgerock. Aquatic plants are sparse and grow to a depth of 6 feet. The overall gillnet catch rate for all fish combined was 21.2 fish/net which was slightly better than average compared to past catches. Total yield was 32.9 lbs/net which was below average for the lake. Fish species sampled in gill nets were walleye, northern pike, yellow perch, white sucker, rock bass, smallmouth bass, and cisco. The overall trapnet catch rate for all fish combined was 8.3 fish/net which was slightly better than average compared to past catches. Total yield was 8.7 lbs/net which was also better than average. Eighty-nine walleye were sampled in gill nets for a catch rate of 9.9 fish/net, which was very good compared to past surveys on Triangle and other similar lakes. Sizes ranged from 8 to 28 inches with an average of 14 inches, which was slightly smaller than past surveys. Growth rates were good with the average fish reaching 15 inches at four years old. Ages ranged from 1 to 18 with the strongest year classes coming from 2017 and 2018, the latter being a stocked year. Triangle is stocked with walleye fry every three years. The northern pike gillnet catch rate was 3.3 fish/net which was good compared to similar lakes and better than average for Triangle Lake. Lengths ranged from 19 to just over 38 inches with an average of 23 inches, which was similar to past surveys. Nine smallmouth bass were sampled in gill nets for a catch rate of 1.0 fish/net which was above average compared to other similar lakes and right at Triangle's historic average. The average weight was over two pounds which was very good compared to other similar lakes. Lengths ranged from 8 to 19 inches with an average of nearly 15 inches. Although the sample size was small, the fish aged did show exceptional growth rates with the fish reaching 12 inches by age four. Ages ranged from 3 to 11 years. Twenty-six yellow perch were sampled in gill nets for a catch rate of 2.9 fish/net which was above average compared to other similar lakes and past surveys on Triangle. Sizes were small with a range from 6 to 8 inches. Rusty crayfish, which are an invasive species, were first observed in Triangle Lake in the 1986 survey. Subsequent counts of rusty crayfish caught in gill nets have bounced around but generally remained high over time. The 2020 survey sampled them at 66.3 crayfish/net which was the highest catch rate since 2003.

Triangle Lake is located 13 miles east of Ely. There are two "remote" public accesses. The most commonly used access is a 50 yard roller portage between the southern shore of Ojibway Lake and the northern shore of Triangle Lake. The other access is on the southern shore and is a 160 rod portage to the North Kawishiwi River. This 300 acre lake contains no major inlets and only one outlet which is about 90 ft long and drops 4 ft in elevation to Ojibway Lake. The lake has a maximum depth of 45 feet and the water color at the time of the survey was green with a slight algae bloom. On July 28, 2014 Triangle was thermally stratified with a surface temperature of 73F and a bottom temperature of 43F. Oxygen levels were adequate to a depth of 22 feet where the water temperature was 48F. Lake bottom substrates along the shoreline of Triangle Lake are mostly boulder, rubble, gravel, and ledgerock. Aquatic plants have been greatly reduced by rusty crayfish. Pondweeds were common in the 1975 fisheries lake survey, but are rare today. The overall gillnet catch rate for all fish combined was 14.0 fish/net which is slightly below the average catch rate for the lake. Fish species sampled in gill nets were walleye, northern pike, white sucker, yellow perch, tullibee, smallmouth bass, rock bass, largemouth bass, and burbot. The overall trapnet catch rate for all fish combined was 11.0 fish/net which ranks second out of seven assessments that used trap nets on this lake. Fish species sampled were rock bass, bluegill, walleye, northern pike, smallmouth bass, yellow perch, and white sucker. Forty-five walleye were sampled in gill nets for a catch rate of 5.0 fish/gill net. This catch rate is very good compared to other similar lakes throughout the state. This catch rate also ranks 8th out of 10 previous surveys, the highest catch rate being 13.4 fish/net in 1998. Fish captured in gill nets ranged in size from 10 to 30 inches with an average of 13 inches. Walleyes averaged 1.3 pounds which is just below average when compared to other similar lakes. Growth rates were very good when compared to other investigations of lakes in the Tower area. Ages ranged from 1 to 18. The 2012 year class was by far the strongest with 64% of the total catch coming from that year. The largest walleye captured in 2014 was 30 inches which is the largest walleye captured from the lake to date. The northern pike gillnet catch was 2.6 fish/net which is very good compared to other similar lakes throughout the state but fairly average when compared to other surveys from Triangle Lake. Average weight was 5.2 lbs/fish which is very good compared to similar lakes. Lengths ranged from 20 to 41 inches with an average of 28 inches. This average length is better than the historic average of 23 inches. Seven smallmouth bass were sampled in gill nets for a catch rate of 0.8 fish/net which is slightly above average compared to similar lakes and near the historic average for Triangle Lake. The average weight was 1.5 lbs. Lengths ranged from 12 to 15 inches with an average of 14 inches which is better than the historic average of 12 inches. Growth was good when compared to other Tower area lakes. Ages ranged from 3 to 5 years. Cisco numbers averaged 17.2/gillnet in three investigations from 1975 through 1983, then gradually declined and have been less than 1.0/gillnet in the last five investigations. This decline was coincident with the introduction and expansion of walleye and rusty crayfish populations. The 2014 catch was slightly better at 1.2 fish/net, but certainly not a major bump. Cisco lengths ranged from 8 to 17 inches with an average of 11 inches. Size structure has remained relatively unchanged over the years. Twenty-five bluegill were captured in trap nets for a rate of 2.8 fish/net which is low compared to other similar lakes throughout the state. The average weight was 0.1 lb/fish. Lengths ranged from 4 to 6 inches. Sizes were on par with previous surveys as it appears the lake has always had a small population of relatively small sized bluegills. Rock bass numbers were high with 55 fish sampled in trap nets for a CPUE of 6.1 fish/net. This catch rate is quite high compared to other similar lakes throughout the state. This seems normal for Triangle Lake though as the historic average trapnet catch is nearly 4.0 fish/net. Lengths ranged from 5 to 6 inches. Rusty crayfish (an invasive species) were first observed in the 1986 investigation and "many" were reported in the gill nets in 1989. Subsequent counts of rusty crayfish caught in gill nets have bounced around but generally remained high over time: 22.5/net in 1991, 12.5/net in 1993 112.0/net in 1998, 67.1/net in 2003, 32.0/net in 2008, and 28.7/net in 2014. Many rusty crayfish can be seen scurrying in the gravelly shallows along the shoreline of this lake.

Triangle Lake Is in Ecological Lake Class 3, which consists of 72 lakes in northeast Minnesota that are deep, have irregularly shaped shorelines, and have very clear and soft (unmineralized) water. Triangle Lake is shallower and has harder (more mineralized) water than typical for this lake class. Triangle Lake ranks as oligotrophic according to Carlson's Trophic State Index. Triangle Lake was thermally stratified on 07/21/2008 with a surface temperature of 71 F and a bottom temperature of 42 F. Adequate oxygen for fish (more than 2 ppm) was retained to a depth of 19 ft, where the temperature was 54 F. Triangle Lake has no inlets. The outlet is about 90 ft long and drops about 4 ft in elevation to Ojibway Lake. It has logjams and a beaver dam with a 1 ft head that prevent fish movement. Lake bottom substrates along the shoreline of Triangle Lake are mostly boulder, rubble, gravel, and ledgerock. Aquatic plants are sparse and grow to a depth of 6 ft; shoreline plants (sedges and sweetgale) and water horehound are the most common plants. Aquatic plants have been greatly reduced by rusty crayfish. Pondweeds (Potamogeton spp.) and water milfoil were common in the 1975 fisheries lake survey, but were rare in the 2003 survey. Access to Triangle Lake is by a 150 ft roller portage from Ojibway Lake or by a 160 rod portage from the Kawishiwi River. Anyone using the roller portage should beware of the bolt heads on the sides of the rollers. There is potential to damage or put a hole in the bottom of a boat. About 75 percent of the shoreline is in Federal ownership. Privately owned lands are along the southeast shore. There are six private cabins and two public campsites (maintained by the US Forest Service) on the lake. Four of the cabins were occupied during the 2003 fisheries lake survey. Summer boat fishing pressure was estimated by a 1986 aerial survey at 2.5 angler-hours/acre, which was considered to be light pressure at the time. Current fishing pressure is probably moderate. Fish sampling in the 2008 investigation consisted of nine gillnets and nine trapnets. Nine previous fisheries investigations on this lake dating back to 1975 used 2-9 gillnets. Five of these previous investigations also used 8-9 trapnets. Shoreline seining was done during the initial lake survey in 1975 and in the re-survey in 2003. All of these investigations were done late in the summer, from late July through early September. Fish populations in 2008, as in most recent investigations, were dominated by walleye, followed by northern pike and white sucker. Cisco catches have declined over time on this lake, while rock bass numbers have increased. The total catches of fish (all species combined) in this lake (and in other lakes in this lake class) were quite low, indicating low biological productivity. Walleye were not captured in the initial 1975 investigation on Triangle Lake and periodic walleye fingerling and fry stocking began in 1976. The walleye catch in 2008 of 6.9/gillnet was in the fourth quartile for this lake class and was near the median catch of 6.5/gillnet for all investigations on this lake since stocking began. Walleye sizes in 2008 averaged 12.3" (0.9 lb), which was in the first quartile for this lake class and was smaller than the average size of 16.1" in all investigations on this lake. The largest walleye captured in 2008 was 29.3". Although walleye from a number of year-classes were captured in 2008, most walleye (69 percent) were age two, from the fry-stocked year of 2006. Walleye fry are stocked every third year in Triangle Lake and most walleye are from stocked years. Growth of walleye captured in 2008 was normal by area standards. Northern pike numbers in 2008 (2.2/gillnet) were in the third quartile for this lake class and were similar to the median catch of 2.6/gillnet in all investigations on this lake. Pike sizes in 2008 averaged 22.6" (2.8 lb), which was in the second quartile for this lake class and was similar to the average size of 22.8" in all investigations on this lake. The largest pike captured in 2008 was 39.4". Most of the pike captured in 2008 were ages three or four. Growth of pike captured in 2008 was normal by area standards. Cisco numbers averaged 17.2/gillnet in three investigations from 1975 through 1983, then gradually declined and have been less than 1/gillnet in the last five investigations, from 1991 through 2008. This decline was coincident with the introduction and expansion of walleye and rusty crayfish populations. Cisco are a schooling, pelagic species that prefer cool water in or below the thermocline; little of this water is sampled by standard gillnet sets. Some large northern pike and walleye are produced in this lake, and they are likely foraging on cisco. Sucker, rock bass, and yellow perch numbers in 2008 were fairly low, but were in the normal range for this lake class. Bass numbers were low and may have been affected by the high numbers of rusty crayfish in this lake. Rusty crayfish were first observed in the 1986 investigation and "many" were reported in the gillnets in 1989. Subsequent counts of rusty crayfish caught in gillnets have generally increased over time: 22.5/net in 1991, 12.5/net in 1993 112.0/net in 1998, 67.1/net in 2003, and 32.0/gillnet in 2008. Many rusty crayfish can be seen scurrying in the gravelly shallows along the shoreline of this lake. Neascus (black spot) was observed in a few of the game fish examined in 2008. Neascus is a common parasite that is native to the area. It cannot infect humans, is often removed by filleting, and is killed at temperatures used to cook fish.

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

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

Triangle has a maximum depth of 43 feet and a mean depth of 14.5 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Triangle is from 2020.

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