Fisher Lake
Florence County, WisconsinLimited DataOligotrophic
Fisher Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
Trophically, Fisher Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Within Florence County's 39 graded waters, Fisher Lake sits at rank 2, near the top of the local distribution.
Fisher Lake has no invasive species recorded in Wisconsin state databases as of 2023, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Fisher Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2023-08-10. Grade methodology: LakeGrade methodology.
Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 26.9 ft down. Trophic State Index: 30.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 26.9 ft | A |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 30 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +4.4 m/yr | 2 |
Location
County Ranking
Ranked #2 of 39 lakes in Florence County
Nearby Lakes in Florence County
More Wisconsin Lake Rankings
Other Grade A Lakes in Wisconsin
Waukesha County · Clarity: 14.6 ft
Waukesha County · Clarity: 13.8 ft
Walworth County · Clarity: 19 ft
Washington County · Clarity: 12 ft
Kenosha County · Clarity: 10.1 ft
Washington County · Clarity: 12.5 ft
Oligotrophic Lakes in Wisconsin
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Fisher Lake covering fish populations, stocking, water quality, and management. 4 reports on file.
- 2021Fisher Lake spring shocking survey, 2021Spring Shocking Survey · WI DNR · 2021 (PDF)
- 2021Patten Lake fisheries summary report, 2021Fisheries Survey · WI DNR · 2021 (PDF)
- 2016Brule River Flowage fisheries summary report, 2016Fisheries Survey · WI DNR · 2016 (PDF)
- 2016Keyes Lake fisheries summary report, 2016Fisheries Survey · WI DNR · 2016 (PDF)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2023-08-10
Monitoring stations: 2