Tioga Mine Pit

Itasca County, Minnesota - DNR stocking history, depth and survey data

Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 31094600

DNR records show 18 stocking entries at Tioga Mine Pit since 2016, most recently rainbow trout adults in 2025 (150 fish).

• Tioga Mine Pit has 18 DNR stocking records across 10 years (2016-2025): rainbow trout (17), brown trout (1).
• The most-stocked species by count is rainbow trout: 17,233 fish on record.
• Maximum depth 225 ft; surface area 49 acres, 1 littoral acres, 1.1 miles of shoreline, per the DNR lake survey.
• Average water clarity (Secchi depth) 27.0 ft.
• Fish species DNR lists here: largemouth bass, rainbow trout, rock bass.
• 1 public access on the DNR list.
• Most recent DNR fish survey: September 28, 2021 (targeted survey).
• Itasca County, nearest town Cohasset; DNR lake number (DOW) 31094600.

Stocking history

¹ fish purchased and stocked by private citizens and sporting groups. ² fish purchased by the DNR for stocking.

Public accesses

DNR fish survey, 2021

Catch per net (CPUE) is the DNR survey's count per gill net or trap net set; higher means more of that species were sampled, not a fishing forecast. Top species per gear shown; where we have no verified common name for a DNR code, the code itself is shown.

Tioga Mine Pit is a 51 acre abandoned iron mine pit located in south-central Itasca County, approximately three miles south of Cohasset, MN. Tioga Pit has a maximum depth of 225 feet; however, only two percent is 15 feet or less in depth. The Secchi disk reading during the 2015 survey was 27.0 feet. Previous Secchi disk readings have ranged from 15 to 43 feet. A state-owned public access is located on the northeast shore. The area receives considerable recreational use. Residential development is currently limited to the southwest corner of the mine pit. Tioga Pit has long been managed as a put-and-take trout fishery and Rainbow Trout are the primary management species. The Iron Range Resources and Rehabilitation Board (IRRRB) stocked yearling Rainbow Trout annually in the spring. The fisheries lake management plan (LMP) was last revised in 2016. The management goal was to maintain trout catches of three per gill net in fall surveys. A population assessment was conducted in late September of 2021 to determine the status of the fish community. This assessment consisted of three gill nets and three trap nets. Rainbow Trout abundance appeared to be low as only two trout were captured in gill nets and none in trap nets. The resulting catch rate failed to meet the management goal. Both trout exceeded 15 inches, however, indicating that at least some trout survival occurred and that angling opportunities for larger trout exist. The success of put-and-take trout fisheries is often difficult to assess. Low trout catch rates could indicate poor survival of stocked fish, which would suggest a failed fishery or could be the result of high angler harvest and utilization, which would indicate a successful program. Given the catch rate and size quality, it appears that good trout fishing opportunities likely exist following spring stocking but numbers may decline by fall. Other species sampled included Largemouth Bass and Rock Bass. Competition or predation may limit trout survival and growth in Tioga Pit. Tioga Mine Pit is not known to support invasive species. Anglers and boaters are reminded to help stop the spread of invasive species by removing all aquatic plants from boats, trailers and equipment. All drain plugs must be removed and live and bait wells must be drained before leaving the access. Anglers and boaters are encouraged to power wash and thoroughly dry all equipment prior to use in another water body. Anglers are also reminded that it is unlawful to use live minnows for bait in Tioga Mine Pit and that introduction of non-trout fish species is…

Minnesota DNR survey narrative, September 28, 2021.

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