Conchu

Conchu is a 50-acre designated stream trout lake located 12 miles east of Ely in the Boundary Waters Canoe Area. It is deep, clear, and relatively low in productivity with a maximum depth of 67 feet. Aquatic vegetation is sparse and limited to a few shallow fringes. Trout stocking in Conchu was discontinued after 2010 following reductions in the state stream trout program. The presence of both northern pike and largemouth bass, and corresponding decreases in assessment catches resulted in the decision to cease trout stocking. Access to Conchu is from the North Kawishiwi River. Travel time is about equal from either the Lake One Entry Point, Ojibway Lake, or Pickerel Lake. Access via Greenstone is also possible for those with a hearty portage appetite. The portage to Conchu is approximately 100 yards. It is a fair climb, but the overall portage condition was excellent. Previously, a winter access trail existed directly between Greenstone and Conchu via a beaver drainage. The absence of a winter trout fishery has resulted in reclamation of this route by nature. A lone USFS designated campsite exists on the southern shore east of the portage. Largemouth bass and white sucker were present in low numbers. Largemouth bass lengths ranged from 12 to 17 inches with an average length of 15 inches. The survey crew observed several more largemouth while paddling the lake. Bass are considered net-shy and are often underrepresented by standard sampling gear. Largemouth are likely far more abundant in Conchu than this survey suggests. Although Conchu is no longer managed for stream trout it is still listed as a designated trout lake. Anglers wishing to pursue largemouth are required to possess a trout stamp.

Conchu Lake is in Ecological Lake Class 4, which consists of 47 lakes in northeast Minnesota that are small, deep, and have clear and soft (unmineralized) water. Conchu Lake was thermally stratified on 05/29/2007 and retained good oxygen for trout (more than 5 ppm) to a depth of 34 ft, where the temperature was 40 F. Testing done in several investigations on Conchu Lake prior to 1988 showed that in midsummer, 5 ppm oxygen was retained to a depth of about 20 ft, where the temperature was about 50 F, and the Secchi water clarity ranged from 7 ft to 12 ft. Conchu Lake is in the Boundary Waters Canoe Area Wilderness. It has an inlet from Uranus Lake with a waterfall that prevents upstream fish movement. The outlet to the Kawishiwi River has a beaver dam and a 4 ft falls limiting fish movement. Lake bottom substrates along the shoreline of Conchu Lake are mostly rubble, ledgerock, and gravel. Aquatic plants are sparse and grow to a depth of 10 ft; sedges and waterlilies are the most common plants. Conchu Lake was poisoned with rotenone by a helicopter with a spray apparatus in the fall of 1984, killing most of the northern pike, white sucker, rock bass, yellow perch, pumpkinseed sunfish, and largemouth bass that were present. Uranus Lake was poisoned at the same time, removing populations of minnows. Some white sucker apparently survived the 1984 poisoning, as sucker were captured in the 1985 assessment. Largemouth bass up to 14" were reported by anglers in 1989 and were captured in the 1990 assessment and several subsequent assessments. A few large northern pike were reported by anglers in the early 90's and were captured in assessments in 1994 and 2003. Although northern pike catches were low, their sizes have been very large (up to 41") and trout were found in their stomachs. Following the 1984 poisoning, Conchu Lake was initially stocked with splake and brook trout. Splake stocking was discontinued in Conchu Lake and all other managed stream trout lakes in the Boundary Waters Canoe Area Wilderness after 1988 at the request of the U.S. Forest Service because they were not considered to be an indigenous species. Brook trout fingerlings have been stocked annually since 1988. The 2007 trout assessment consisted of four gillnets set in late May. Six previous trout assessments, each consisting of 2-4 gillnet sets, were done from 1986 through 2003. Five brook trout, ranging in length from 6-9", were captured in the 2007 assessment; all had been stocked (air-dropped from a float plane) the previous fall. Four of these trout had insects and amphipods in their stomachs, while the remaining trout had an empty stomach. The total catch of trout by weight in 2007 of 0.3 lb/gillnet was much lower than the median catch of 6.6 lb/gillnet in all assessments on this lake and was lower than the median catch of 3.7 lb/gillnet in recent assessments of 25 stream trout lakes (excluding mine pit lakes) in the Tower Fisheries Management Area. No white sucker, northern pike, or largemouth bass were caught in the 2007 assessment. Anglers have reported catching largemouth bass and occasional large northern pike in Conchu Lake in recent years.

Conchu Lake is in Ecological Lake Class 4, which consists of 47 lakes in northeastern Minnesota that are small, deep, and have clear and soft (unmineralized) water.Conchu Lake was thermally stratified on 06/02/2003 and retained good oxygen for trout (more than 5 ppm) to a depth of 27 ft, where the temperature was 42 F. In midsummer, 5 ppm oxygen is retained to a depth of about 20 ft, where the temperature is about 50 F.Conchu Lake has an inlet from Uranus Lake with a waterfall which prevents fish movement. The outlet to the Kawishiwi River has a beaver dam and a 4 ft falls limiting fish movement. Shoal water substrates on Conchu Lake are mostly rubble, ledgerock, and gravel. Plants are sparse and grow to a depth of 10 ft; sedges and waterlilies are the most common plants.Conchu Lake was poisoned with rotenone in the fall of 1984, killing most of the northern pike, white sucker, rock bass, yellow perch, pumpkinseed sunfish, and largemouth bass that were present. Uranus Lake was poisoned at the same time. Conchu Lake was initially stocked with splake and brook trout. Splake stocking was discontinued in all lakes in the Boundary Waters Canoe Area Wilderness after 1988 at the request of the U.S, Forest Service because they are not an indigenous species. Brook trout have been stocked annually since 1988. The 2003 trout assessment consisted of four gillnets set in early June. Five previous trout assessments, each consisting of 2-4 gillnet sets, were done from 1986 through 1998.Two 7" brook trout were captured in the 2003 assessment; both had been stocked (air-dropped from a float plane) the previous fall. The total catch of trout by weight in 2003 of 0.1 lb/gillnet was much lower than the median catch of 7.9 lb/gillnet in previous assessments on this lake and was lower than the median catch of 4.6 lb/gillnet in recent assessments of 25 stream trout lakes (excluding mine pit lakes) in the Tower Fisheries Management Area.One large northern pike (36", 12 lb) was captured in the 2003 assessment. A 41" pike with several brook trout fingerlings in its stomach was captured in the 1994 assessment, and several large pike have been caught by anglers in recent years.Two largemouth bass were captured in the 2003 assessment. Largemouth bass have been captured in all four investigations from 1990 to the present.No white sucker were captured in the 2003 assessment. White sucker were captured in the 1994 and 1998 assessments.

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

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

Conchu has a maximum depth of 67 feet and a mean depth of 18 feet, per Minnesota DNR data.

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

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