Joe Martin Lake

On the LakeGrade rubric, Joe Martin Lake pulls an A: clarity at 36.7 ft and 9 µg/L of phosphorus put it in the top bracket for Minnesota. 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.

Trophically, Joe Martin Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake's 77 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. Joe Martin Lake is small — 68 acres alongside 1.4 miles of shoreline — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Within St. Louis County's 187 graded waters, Joe Martin Lake sits at rank 23, near the top of the local distribution.

Joe Martin Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. The fishery is bass-led, with 8 documented species across the lake's records. The lake lacks a documented public access point, so visitor use is limited. Multiple sampling years from Minnesota PCA volunteers and partner agencies back the grade, so the letter should hold steady absent a major watershed shift.