Extortion

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.

This assessment was the last intended to evaluate alternating stocking of brown trout and rainbow trout in this lake. The most recent (2010) lake management plan called for Brown Trout stocking to be discontinued after 2011, while Rainbow Trout stocking would continue, at the current frequency of two years of every three. Although Rainbow Trout stocked in 2010 and 2012 should been vulnerable to the sampling gear used in this assessment, none were taken. Survival of recent stockings may have been low; however, with only two gill net sets used, failure to capture Rainbow Trout even if they were present in reasonable numbers would not be unusual. The normal range for Rainbow Trout gill net catches in fall assessments of stream trout lakes in this area is 1.0 - 6.5 fish/net. An assessment of Extortion Lake in 2009 yielded a Rainbow Trout gill net catch of 4.0 fish/net. Brown trout from stockings done in 2011 and 2008 were collected in this assessment. Brown Trout lengths ranged from 14.1 to 21.4 inches, indicating the lake supported a fairly high-quality population. Growth of the two five-year-old fish from which scale samples were obtained was similar to growth observed among other brown trout of the same age sampled in this area. The presence of large brown trout in this lake may have resulted in some loss to predation of stocked trout fingerlings. Rainbow Trout fingerlings stocked in 2006 and 2007, in the absence of an established brown trout population, seemed to have exhibited good survival and were sampled in fair numbers in the 2009 assessment.

Rainbow trout abundance and average size appeared to have been at normal levels for a stream trout lake in this area. Management goals for the species (gill net catch over 3.0 fish/set) were met in 2009. Fish from the 2007 kamloops and 2006 arlee-strain stocking contributed to the 2009 catch. No other rainbow trout year classes could have been present, since the species was first stocked in 2006, and 2009 stocking occurred after this assessment. Growth of fish of both strains had been relatively slow. Survival of stocked brown trout may have been unusually poor. No brown trout from the 2005 or 2008 stockings were taken. Brown trout are normally fairly vulnerable to gill net sampling gear; the normal range for fall gill net catches in brown trout lakes in the Grand Marais area is 2.0-6.0 fish/set. Fish from the 2005 stocking should still have been present in 2009, since brown trout have generally shown good long-term survival in even heavily-fished lakes in the area. Fish from the 2008 stocking should have been large enough to be taken in the sampling gear used.

Based on Minnesota DNR survey data, anglers target Brown Trout, Rainbow Trout, and Splake in Extortion. See the full species list above for catch rates, size structure, and quality scores.

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

Extortion has a maximum depth of 36 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Extortion is from 2018. Surveys this old should be treated with some caution — fish populations change over time.

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