Gilas Lake

On the LakeGrade rubric, Gilas Lake pulls an A: clarity at 15.0 ft and 13 µg/L of phosphorus put it in the top bracket for Wisconsin. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.

Trophically, Gilas Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. Gilas Lake is unusually deep for Wisconsin at 88 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. Gilas Lake covers 135 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Marinette County's 21 graded waters, Gilas Lake sits at rank 4, near the top of the local distribution.

Zebra mussels have been documented at Gilas Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.