Devilfish

The 2020 survey of Devilfish Lake was scheduled in the 2018 lake management plan (LMP) revision to determine if the Walleye population goal could be met in the absence of stocking. The long-term goal for Walleye in Devilfish Lake, established in the 1990 LMP, is to maintain a population with a minimum gill net catch of 4.0 fish/net. That goal was met in most surveys done through 2008. Walleye were present in fair numbers in Devilfish Lake in 2020, with a few larger fish available. However, the 2020 Walleye gill net catch was the lowest ever recorded in this lake, and fell below the normal range for a lake of this type. The 2020 survey gill net catch was the third in a row that failed to meet the long-range goal for the Walleye population, with each catch lower than the previous. The mean weight of Walleye sampled in gill nets in 2020 was the highest observed for this lake, mainly due to a lack of small Walleye in the catch rather than high numbers of large fish. It is clear from results of the 2016 and 2020 surveys that Walleye natural reproduction has been inadequate, and that a resumption of stocking is needed to meet the goal for this population. Aging results in 2020 indicated only relatively weak natural year classes had been produced since stocking ceased in 2010. Although growth for the youngest Walleye taken in this survey appeared to have been adequate (based on a very small sample size), growth for older fish had been slow. The oldest fish sampled was a 19-year-old fish that was just 15.8 inches long when captured. The largest fish taken (27.6 inches) was 16 years old. Smallmouth Bass, introduced illegally and first documented in Devilfish Lake in 2008, have become well-established since that time. They appeared to have been abundant in 2020, with fair numbers of fish over 12 inches present. Smallmouth Bass collected in all gears in 2020 ranged in length from 6.8 to 14.0 inches. Smallmouth Bass are considered an undesirable species for Devilfish Lake due to the additional competition they impose on Walleye for limited forage. In some lakes where they have been introduced we have seen the nearly complete elimination of small fish species in the nearshore fish community. In addition, deep drops in the production of young-of-year Walleye and Yellow Perch, with reduced Walleye recruitment, have been seen in some cases. The White Sucker gill net catch in 2020 fell within the normal range for a lake of this type, and was similar to past catches in Devilfish Lake. A majority of the White Sucker sampled were too large to serve as forage for Walleye. White Sucker can compete with Walleye for some types of invertebrate forage, resulting in slower Walleye growth where White Sucker abundance is high. Yellow Perch, another species that was introduced illegally into Devilfish Lake, have been sampled periodically since 1989. None were found in 2016 or 2020. Rainbow Smelt and Lake Trout were also present at one time in Devilfish Lake, but neither species has been observed since the 1980s. In 2016 crews from the 1854 Treaty Authority surveyed a number of Cook County lakes for the presence of Spiny Waterflea. They documented the presence of Spiny Waterflea in Devilfish Lake. The lake is now designated an infested water.

Devilfish Lake is located about 20 miles northeast of the City of Grand Marais. There is a concrete public access located within the Devilfish Lake State Forest Campground. Devilfish Lake is an Ecological Class 6 lake, which is characterized as deep, with moderate littoral coverage, very irregular shorelines, and very soft bog-stained water. Walleye has been the primary management species in Devilfish Lake since 1981. Walleye fry were stocked regularly through 2010. The 2016 survey of Devilfish Lake was the second of two scheduled in the 2010 lake management plan to determine if the Walleye goals for the lake could be met in the absence of additional stocking. The long-term goal for Walleye in Devilfish Lake is to maintain a population with a minimum gill net catch of 4.0 fish/net. The current plan will be revised in 2018 based on the results of the 2012 and 2016 surveys. The 2016 Walleye gill net catch was the lowest recorded for Devilfish Lake since 1982, and was also low compared to other Class 6 lakes in the area. The 2016 catch failed to meet the long-range goal for the Walleye population for the second consecutive assessment. The mean weight of Walleye sampled in gill nets was the highest observed for this lake, which was the result of a near complete absence of small Walleye, and the collection of a few large individuals. Natural reproduction appeared to have been poor in recent years; only one fish younger than five years of age was sampled, and no young-of-year fish were taken in quarter-inch trap nets. Most of the Walleye collected in 2016 were between five and ten years old, indicating natural reproduction was more consistent in Devilfish Lake prior to 2012. The 2011, 2009, and 2008 year classes, which were not supplemented by fry stocking, accounted for about 50 percent of the sample in 2016. Several year classes supplemented by fry stocking were also represented in the 2016 survey, with the 2010 year class appearing the strongest. Walleye growth remained slow in Devilfish Lake; fish reached an average length of just 12.3 inches at the end of their fifth year, compared to an area mean of 14.6 inches. Although slow growing, Walleye in Devilfish Lake have the potential to reach large sizes; Walleye up to 28.5 inches long and 17 years old were sampled in 2016. Smallmouth Bass were first documented in Devilfish Lake in 2008, and have been increasing in abundance since that time. The 2016 gill net and 0.75-inch-mesh trap net catches were well above average for Class 6 lakes, and were the highest seen to date in this lake. Smallmouth Bass ranged in size from 5.5 to 15.8 inches, with six consecutive year classes represented in the catch. A majority of the Smallmouth Bass sampled in 2016 were four or five year old fish. Growth of these fish had been slow; by the end of their fourth year fish reached a mean length of 8.6 inches, compared to an area average of 10.2 inches. Smallmouth Bass are considered an undesirable species for Devilfish Lake due to the additional competition they impose on Walleye for limited forage. The White Sucker gill net catch in 2016 fell within the normal range for Class 6 lakes, and was similar to past catches in Devilfish Lake. A majority of the White Sucker sampled were too large to serve as forage for Walleye. Yellow Perch, another species that was introduced illegally into Devilfish Lake in the early 1980s, have been sampled periodically since 1989. None were found in 2016. Quarter-inch-mesh trap nets are usually effective gear for sampling this species, and the failure to capture any in 2016 suggests their abundance remains very low. No other fish species were sampled in 2016. Rainbow Smelt and Lake Trout were at one time present in Devilfish Lake, but neither species has been observed since the 1980s. Additional species found in past surveys of Devilfish Lake include Creek Chub and Central Mudminnow. Migrant Brook Trout from Portage Brook, the lake's outlet, have been observed on occasion in Devilfish Lake. Spiny Waterflea, a prohibited aquatic invasive species, were found in Devilfish Lake in 2016, and the lake is now considered an infested water. Anglers and boaters are reminded to review the recommended actions for cleaning watercraft and gear before and after accessing any waterbody, and to adhere to all Minnesota aquatic invasive species laws to protect Minnesota lakes and rivers from additional infestations.

Devilfish Lake is currently managed for walleye. The long range goal for the species (from the 2010 lake management plan) is to maintain a population with a minimum gill net catch of 4.0 fish/set. No size goal was set because Devilfish Lake is known mainly for producing high numbers of small walleye. This was the first of two assessments scheduled to determine whether the walleye goal in this lake could be met without additional stocking. In 2012, Clean Water Legacy funding allowed areas across the state to do some nearshore fish community sampling to improve our ability to use a fish-based Index of Biotic Integrity (IBI) to identify disturbed aquatic ecosystems. Devilfish Lake was selected for nearshore sampling because its accessibility allowed for use of the sampling gears required. The 2012 walleye gill net catch was similar to catches seen in this lake since walleye were reintroduced in the early 1980s, but it did not meet the long range goal in the current plan. The gill net catch and the mean weight for walleye taken in gill nets fell within normal ranges for the lake class. A few larger walleye were present, but most were under 16 inches in length. Several year classes contributed to the 2012 catch. The two strongest year classes (2007 and 2006) had been supplemented by stocking, but some purely natural year classes had been produced as well. Walleye growth had been slow; five-year-old fish reached a mean length of 12.6 inches at the end of their fifth year, compared to an area mean of 14.4 inches in similar lakes. A lack of forage (few, if any, yellow perch), and competition from smallmouth bass and white sucker probably accounted for the slow walleye growth observed in 2012. Smallmouth bass have recently become established in Devilfish Lake, and appeared to have been abundant in 2012. The 2012 gill net catch was within the normal range for the lake class, but the trap net catch was well above normal. Smallmouth bass collected ranged in length from 5.2 to 15.0 inches, and several year classes were strongly represented in the catch. Growth had been fast; four-year-old fish reached an average length of 11.3 inches by the end of their fourth year, compared to an area mean of 9.8 inches. Although yellow perch were introduced (illegally) in this lake in the 1980s, and have been taken in some assessments since that date, none were found in 2012. Quarter-inch-mesh trap nets usually sample yellow perch very effectively, and the failure to take any in that gear suggests their abundance must have been very low. The white sucker gill net catch was within the normal range for the lake class, and was similar to past catches in this lake. Most of the white sucker taken were too large to serve as forage for any but the largest walleye in the lake. Sampling of the nearshore fish community was done using quarter-in-mesh trap nets, a 15-ft beach seine, and backpack electrofishing gear. Prior to sampling done in 2012, Devilfish Lake was known to support populations of walleye, smallmouth bass, white sucker, yellow perch, creek chub, and central mudminnow. Brook trout had been found occasionally, as migrants from Portage Brook. Lake trout and rainbow smelt, present at one time, had disappeared from the lake by the mid 1980s. Nearshore sampling in 2012 added bluntnose minnow (a single fish) to the list of fish species known to be present in this lake.

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

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

Devilfish has a maximum depth of 40 feet and a mean depth of 13 feet, per Minnesota DNR data.

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

Yes — Devilfish has confirmed spiny waterflea. Clean, drain, and dry your equipment to avoid spreading invasives to other waters.