Bladder Lake

Bladder Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 18 puts Bladder Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake bottoms out at 35 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Bladder Lake is small — 84 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Within Bayfield County's 55 graded lakes, Bladder Lake ranks 41 — below the local median, though not at the bottom.

Bladder Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 3 documented species — a notable draw for Wisconsin anglers. 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.