Thrasher Lake
Cook County, Minnesota - DNR stocking history, depth and survey data
Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 16019200
DNR records show 8 stocking entries at Thrasher Lake since 2016, most recently splake fingerlings in 2024 (2,500 fish).
- Thrasher Lake has 8 DNR stocking records across 8 years (2016-2024): splake (8).
- The most-stocked species by count is splake: 21,701 fish on record.
- Maximum depth 27 ft; surface area 24 acres, 23 littoral acres, 1.1 miles of shoreline, per the DNR lake survey.
- Average water clarity (Secchi depth) 10.3 ft.
- Fish species DNR lists here: splake.
- 1 public access on the DNR list.
- Most recent DNR fish survey: (standard survey).
- Cook County, nearest town Grand Marais; DNR lake number (DOW) 16019200.
Stocking history
| Year | Species | Size | Number | Pounds |
|---|---|---|---|---|
| 2024 | Splake | fingerlings | 2,500 | 78.7 |
| 2023 | Splake | fingerlings | 3,001 | 119.6 |
| 2022 | Splake | fingerlings | 2,500 | 66.1 |
| 2021 | Splake | fingerlings | 3,700 | 95.1 |
| 2020 | Splake | fingerlings | 2,500 | 81.2 |
| 2019 | Splake | fingerlings | 2,500 | 67.2 |
| 2018 | Splake | fingerlings | 2,500 | 113.6 |
| 2016 | Splake | fingerlings | 2,500 | 56.8 |
Field note · Minnesota stocks by year, not by truck day: walleye fry go in within weeks of ice-out, fingerlings and yearlings mostly in fall, and stream trout in spring and fall. A row here means the fish went in during that year; DNR adds the year's rows after the fact, so the current year can look empty until winter.
Public accesses
| Type | Owner | Where |
|---|---|---|
| CA | USF | Short carry-down off an old logging road, off Forest Road 323. Parking for two vehicles. |
DNR fish survey, 2021
| Species | Gear | Catch per net | Total catch | Avg lb |
|---|---|---|---|---|
| Splake | Standard gill nets | 23.50 | 47 | 0.78 |
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.
Thrasher is a designated stream trout lake that has been managed for trout since 1972. Rainbow and Brook Trout have been stocked in this lake in the past, but Splake stocking began in 1982, and since 1995 2,500 Splake fingerlings have been been stocked annually. The goal established for Splake in the latest (2013) lake management plan (LMP) was to maintain a catch in 0.75-in-mesh trap nets of at least 2.5 fish/net, with three catchable-sized (over 10 inch) year classes present, including some fish larger than 18 inches. The equivalent catch goal in terms of gill net catch would be a catch of about 10 fish/net. This was the second of two standard surveys scheduled in the 2013 plan to determine whether temperature-oxygen conditions continued to be suitable for stream trout and to determine whether long range goals for Splake were met by the current splake stocking regime. The first survey was completed as planned in 2016. Splake appeared to have been abundant in Thrasher Lake in 2021, and the population included fair numbers of larger fish (over 18 inches). The 2021 Splake gill net catch was the highest ever seen in this lake. It exceeded the normal range for catches in stream trout lakes in this area (5.8-12.0 fish/net), indicating the long range catch goal would have been met in 2021. The catch included four catchable-sized Splake year classes, and several fish over 18 inches in length were taken. Splake as old as six years were present in relatively high numbers, indicating long term survival had been excellent. Splake growth appeared to have been slow; fish reached a mean length of just 10.3 inches at the end of their third year, compared to an area average of 12.6 inches. Slow Splake growth may have been due, at least in part, to the sheer numbers of Splake present and competing for forage in this small lake. No undesirable or competing fish species were sampled in 2021. The only non-trout fish species ever collected in Thrasher Lake have been Fathead Minnow, Finescale Dace, and Pearl Dace. Temperature-oxygen measurements made in mid August as part of this survey suggested that, in 2021 at least, slow growth of Splake was probably not related to stress caused by a lack of cold-water habitat. Splake are believed to have temperature and oxygen requirements similar to those for Brook Trout. Optimal conditions for Brook Trout are water temperatures of 68 F or less, with at least 5.0 ppm dissolved oxygen. On 16 August 2021 those conditions were found at depths of 8.3 to about 15 feet in Thrasher Lake. Even in shallower waters conditions were tolerable…
Minnesota DNR survey narrative, .
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Stocking rows, depths, accesses and survey figures are Minnesota DNR LakeFinder data as of 2026-09-02. Regulations, slot limits and special rules are on the DNR page linked above, not here.
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