Fish Trap Lake

On the LakeGrade scale Fish Trap Lake grades a B, with clarity at 10.0 ft and 22 µg/L of phosphorus placing it above the Minnesota median. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI near 46 places Fish Trap Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. A maximum depth of 42 ft puts Fish Trap Lake in the middle of Minnesota's depth distribution. At 1,164 acres, Fish Trap Lake is one of the larger lakes in Morrison County, with 13.1 miles of shoreline supporting multiple distinct use patterns. Among the 16 graded lakes in Morrison County, Fish Trap Lake sits at rank 8, above the county median.

Zebra mussel presence at Fish Trap Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Fish Trap Lake's fishery is anchored by muskellunge, with 18 documented species in total — a destination water for muskie anglers. A documented public access point at Fish Trap Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Ice-out has been logged at Fish Trap Lake more than two dozen times, putting the median around Apr 17 — a useful baseline for tracking climate trends. 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.