Tyson Lake
Yellow Medicine County, MinnesotaLimited DataEutrophic
Tyson Lake earns a D — measurements through 2024 show persistent nutrient pressure that limits clarity through the summer.
Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. Tyson Lake is a shallow lake at 8 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. At 166 acres, Tyson Lake fits the Minnesota median for monitored lakes, with 3.3 miles of shoreline. Within Yellow Medicine County's 5 graded lakes, Tyson Lake ranks 3 — below the local median, though not at the bottom.
Tyson Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Walleye are documented at Tyson Lake, one of 8 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 2024-08-13. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 4.5 ft. Trophic State Index: 55.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.5 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 55 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 8 ft |
| Surface Area | 165.85 acres |
| Shoreline Length | 3.3 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Tyson Lake (14-day solunar calendar)
→ Is it safe to eat fish from Tyson Lake? (mercury & PFAS guide)
→ Tyson Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.275 m/yr | 5 |
Location
County Ranking
Ranked #3 of 5 lakes in Yellow Medicine County
Nearby Lakes in Yellow Medicine County
More Minnesota Lake Rankings
State Parks Near Tyson Lake
Other Grade D Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2023-09-13 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 150.80 | 0.22 lb |
| Walleye | 48.29 | 1.33 lb |
| Yellow Perch | 10.61 | 0.33 lb |
| OSS | 7.09 | 0.03 lb |
| Bluegill | 7.08 | 0.32 lb |
| Hybrid Sunfish | 3.22 | 0.17 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.
Black Bullhead
Walleye
Yellow Perch
OSS
From the 2023-09-13 survey
A targeted fall night electrofishing survey was conducted on Tyson during September 13, 2023 to evaluate young of year "YOY" (fingerling sized) Walleye numbers due to fry stocking/natural reproduction. One station was sampled for 10 minutes at dusk. The water temperature was 70 F. Water clarity was poor (6 inches)…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Tyson Lake. 3 reports on file.
- —Fisheries Lake Survey — TysonFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — TysonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — TysonPublic Water Access Sites · MN DNR LakeFinder
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Most recent sample: 2024-08-13
Monitoring stations: 1