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LakeQuality
B

Mud Lake

Becker County, MinnesotaMesotrophic

Mud Lake comes in at a B on the grading rubric — a respectable showing for a Minnesota lake of its size and depth. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. Mud Lake reaches 34 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 1,178 acres, Mud Lake is one of the larger lakes in Becker County, with 9.7 miles of shoreline supporting multiple distinct use patterns. Among the 93 graded lakes in Becker County, Mud Lake sits at rank 37, above the county median.

Zebra mussel presence at Mud Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. The fishery includes walleye alongside the lake's other 16 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been recorded 24 times at Mud Lake, with a median around Apr 24. 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 2024-09-29. Grade methodology: LakeGrade methodology.

Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Good clarity, visible to about 11.5 ft. Phosphorus level: 23.5 µg/L. Trophic State Index: 46.

MetricValueGrade
Water Clarity (Secchi Depth)11.5 ftB
Phosphorus23.5 µg/LB
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)46Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth34 ft
Surface Area1.2K acres
Shoreline Length9.7 mi
Littoral Zone73%
Public AccessYes

Fish Species

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

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

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

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

Invasive Species

zebra mussel

Water Quality Trend: Declining

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

MetricTrendChange/YearYears
Water Clarity Declining-0.135 m/yr5
Phosphorus Declining+1.25 µg/L/yr5

Ice Season

Historical ice data from Minnesota DNR (33 observations).

Typical Ice-Out
Apr 24
Typical Ice-In
Nov 24

Estimated open water season: 214 days

EarliestLatest
Ice-Out2012-03-24 (2012)2013-05-12 (2013)
Ice-In2019-11-07 (2019)2009-12-05 (2009)

Most recent ice-out: 2025-04-07

Location

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County Ranking

Ranked #37 of 93 lakes in Becker County

Nearby Lakes in Becker County

DNR Fisheries Survey Summary

12 surveys on file from MN DNR Fisheries. Most recent: 2021-06-21 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
BNS217.31
Bluntnose Minnow82.96
Fathead Minnow66.65
MMS49.09
BKF38.26
Bluegill27.160.2 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

217 fish · 29 in · 2021-06-21
107540trophy 1023456789

From the 2021-06-21 survey

Floyd (a.k.a., Big Floyd) Lake is a 1,212-acre lake located in Becker County two miles north of the city of Detroit Lakes. Floyd Lake's shoreline is heavily developed, and the lake receives a high amount of angling pressure and recreational use. Floyd Lake consists of two basins, the shallow larger main basin and the…

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 Mud Lake. 3 reports on file.

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Lake details from Minnesota DNR LakeFinder

Ice data from Minnesota DNR Climate

Most recent sample: 2024-09-29

Monitoring stations: 1