Ethel Lake
Otter Tail County, MinnesotaLimited DataOligotrophic
On the LakeGrade scale Ethel Lake grades a B, with clarity at 14.6 ft and phosphorus readings still being added placing it above the Minnesota median.
Trophically, Ethel Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. At 64 ft of maximum depth, Ethel Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. At 191 acres, Ethel Lake fits the Minnesota median for monitored lakes, with 3.2 miles of shoreline. Within Otter Tail County's 97 graded lakes, Ethel Lake ranks 55 — below the local median, though not at the bottom.
Zebra mussel presence at Ethel Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Walleye are documented at Ethel 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 2024-09-26. Grade methodology: LakeGrade methodology.
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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 14.6 ft. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14.6 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 64 ft |
| Surface Area | 191.12 acres |
| Shoreline Length | 3.2 mi |
| Littoral Zone | 36% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Ethel Lake (14-day solunar calendar)
→ Is it safe to eat fish from Ethel Lake? (mercury & PFAS guide)
→ Ethel 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.
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.131 m/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (8 observations).
Estimated open water season: 237 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2005-04-10 (2005) | 2008-05-01 (2008) |
| Ice-In | 2003-11-11 (2003) | 2004-12-14 (2004) |
Most recent ice-out: 2008-05-01
Location
County Ranking
Ranked #55 of 97 lakes in Otter Tail County
Cleaner Lakes Within 30 Miles
Ethel Lake holds Grade B. 5 nearby lakes hold higher grades.
- AWest Battle LakeOtter Tail County · mi · Higher grade (B → A)
- AStuart LakeOtter Tail County · mi · Higher grade (B → A)
- ABlanche LakeOtter Tail County · mi · Higher grade (B → A)
- AOtter Tail LakeOtter Tail County · mi · Higher grade (B → A)
- AEast Battle LakeOtter Tail County · mi · Higher grade (B → A)
Nearby Lakes in Otter Tail County
More Minnesota Lake Rankings
State Parks Near Ethel Lake
Other Grade B Lakes in Minnesota
Oligotrophic Lakes in Minnesota
DNR Fisheries Survey Summary
6 surveys on file from MN DNR Fisheries. Most recent: 2025-07-16 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluntnose Minnow | 74.06 | — |
| Bluegill | 29.58 | 0.2 lb |
| MMS | 24.11 | — |
| Spottail Shiner | 21.53 | — |
| IOD | 14.82 | — |
| Yellow Bass | 9.79 | 0.51 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
Yellow Bass
From the 2025-07-16 survey
A targeted survey of nearshore fish species in Ethel Lake was conducted on July 16 -July 17, 2025, by Lake Biological Monitoring and Assessment (LBMA) Program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Ethel Lake. 4 reports on file.
- —Fisheries Lake Survey — EthelFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Ethel (0965)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — EthelFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — EthelPublic Water Access Sites · MN DNR LakeFinder
EPA Impairment Status
Ethel Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN56-0240-00 · Official waterbody report · Matched by proximity (2.81 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
Ice data from Minnesota DNR Climate
Most recent sample: 2024-09-26
Monitoring stations: 1