Halfmoon Lake

On the LakeGrade rubric, Halfmoon Lake pulls an A: clarity at 52.5 ft and 12 µg/L of phosphorus put it in the top bracket for Wisconsin. 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's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. A maximum depth of 38 ft puts Halfmoon Lake in the middle of Wisconsin's depth distribution. The lake is compact at 28 acres, with partial shoreline records and little volume to buffer nutrient inputs. Halfmoon Lake sits at rank 45 of 66 in Oconto County, in the lower half of the local distribution.

Halfmoon 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. Bass fishing is part of the appeal: the species list runs to 2, anchored by largemouth and/or smallmouth bass. Public access is available — the lake is on the Wisconsin DNR 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.