Extortion Lake

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

Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 16045000

DNR records show 6 stocking entries at Extortion Lake since 2016, most recently rainbow trout fingerlings in 2025 (1,439 fish).

• Extortion Lake has 6 DNR stocking records across 6 years (2016-2025): rainbow trout (6).
• The most-stocked species by count is rainbow trout: 7,473 fish on record.
• Maximum depth 36 ft; surface area 16 acres, 16 littoral acres, 1.5 miles of shoreline, per the DNR lake survey.
• Average water clarity (Secchi depth) 4.1 ft.
• Fish species DNR lists here: rainbow trout.
• 1 public access on the DNR list.
• Most recent DNR fish survey: September 10, 2018 (standard survey).
• Cook County, nearest town Grand Marais; DNR lake number (DOW) 16045000.

Stocking history

Public accesses

DNR fish survey, 2018

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.

Extortion Lake has been managed for stream trout since 1993. It is a deeply bog-stained lake, with conditions suitable for trout usually found only in surface waters. This was the first of three surveys scheduled on this lake in the 2018 lake management plan. Objectives for those surveys were to determine if survival and growth of stocked Rainbow Trout were satisfactory, and to determine whether summer temperature-oxygen conditions remained suitable for stream trout. The Rainbow Trout gill net catch in this survey fell short of the goal from the 2018 plan (a minimum of 3.0 fish/set); however, with the low number of nets used in surveys of this lake, results of multiple surveys are needed to assessment goal attainment with any confidence. The catch fell within the normal range (1.00-5.00 fish/set) for gill-net catches in fall surveys of stream trout lakes in this area. The catch of age-2 and age-3 fish indicated there had been some survival of the last two stocked year classes (2016 and 2015), but the sample size was too low to support any assessment of their growth. As in past surveys of this lake, no undesirable fish species were caught. Late-summer temperature-oxygen data have only been collected on this lake in two surveys (1992 and 1972). Surface waters were cool (64 F) in mid August 1992, but the 1972 survey found water temperatures of 70.5-76.0 F in well oxygenated surface waters in mid August. Most temperature-oxygen profiles on this lake have been done in the fall after surface waters have cooled considerably, and that was again the case in this survey. Surface waters were very cool (61.9 F) on 10 September, but dissolved oxygen abruptly dropped to almost zero between the depths of eight and nine feet. That was typical for this lake, and indicated that in periods when surface waters are excessively warm, there would likely be little or no deeper, colder water with enough oxygen for trout.

Minnesota DNR survey narrative, September 10, 2018.

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