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B

Crookneck Lake

Morrison County, MinnesotaMesotrophic

Crookneck Lake comes in at a B on the grading rubric — a respectable showing for a Minnesota lake of its size and depth. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.

A TSI near 46 places Crookneck Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. Crookneck Lake reaches 22 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 191 acres, Crookneck Lake fits the Minnesota median for monitored lakes, with 2.8 miles of shoreline. Among the 16 graded lakes in Morrison County, Crookneck Lake sits at rank 7, above the county median.

Crookneck Lake is on the Minnesota infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. Walleye are documented at Crookneck Lake, one of 13 fish species on record for the lake. Public access is available — the lake is on the Minnesota PCA public-access list. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-09-15. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Good clarity, visible to about 11.2 ft. Phosphorus level: 22 µg/L. Trophic State Index: 46.

MetricValueGrade
Water Clarity (Secchi Depth)11.2 ftB
Phosphorus22 µg/LB
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)46Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth22 ft
Average Depth8.9 ft
Surface Area191.2 acres
Shoreline Length2.8 mi
Littoral Zone69%
Public AccessYes

Fish Species

black bullhead,black crappie,bluegill,brown bullhead,green sunfish,hybrid sunfish,largemouth bass,northern pike,pumpkinseed,rock bass,walleye,white sucker,yellow perch

Click a species to see all Minnesota and Wisconsin lakes where it is found.

→ Best fishing times for Crookneck Lake (14-day solunar calendar)

→ Is it safe to eat fish from Crookneck Lake? (mercury & PFAS guide)

Crookneck Lake fishing regulations (limits, seasons, special rules)

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

Eurasian watermilfoilzebra mussel

Water Quality Trend: Declining

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable-0.023 m/yr5
Phosphorus Declining+0.95 µg/L/yr5
See year-by-year chart →

Location

Loading map…

County Ranking

Ranked #7 of 16 lakes in Morrison County

Cleaner Lakes Within 30 Miles

Crookneck Lake holds Grade B. 2 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Morrison County

DNR Fisheries Survey Summary

11 surveys on file from MN DNR Fisheries. Most recent: 2023-07-24 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Bluegill95.150.09 lb
Pumpkinseed17.220.13 lb
Largemouth Bass12.721.41 lb
Brown Bullhead10.670.7 lb
Northern Pike7.532.1 lb
Black Crappie6.620.22 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

Length Distributions

Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.

Bluegill

326 fish · 27 in · 2023-07-24
133670234567

Pumpkinseed

69 fish · 37 in · 2023-07-24
2412034567

Largemouth Bass

11 fish · 618 in · 2023-07-24
2106789101112131415161718

Brown Bullhead

16 fish · 713 in · 2023-07-24
95078910111213

From the 2023-07-24 survey

A targeted survey of the nearshore fish community in Crookneck Lake was conducted by Fisheries Index of Biological Integrity (IBI) Program Staff from 24-25 July 2023. Ten sampling sites were evenly spaced around the lake and each was sampled by backpack electrofishing and seining with a 15-foot or 50-foot seine, where…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Crookneck Lake. 3 reports on file.

EPA Impairment Status

Crookneck Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Mercury

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN49-0127-00 · Official waterbody report · Matched by proximity (1.38 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Lake details from Minnesota DNR LakeFinder

Most recent sample: 2024-09-15

Monitoring stations: 2