Mann Lake

Mann Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. 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.

At a TSI of 52, Mann Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake bottoms out at 18 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 253 acres, Mann Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Mann Lake sits at rank 143 of 191 in Vilas County, in the lower half of the local distribution.

Mann Lake has at least one documented invasive species (Banded Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. 2 fish species are documented at Mann Lake, a mixed warm-water community typical for Wisconsin lakes of this size. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.