Boy Bay Lake

On the LakeGrade scale Boy Bay Lake grades a B, with clarity at 7.4 ft and phosphorus readings still being added placing it above the Minnesota median. Secchi readings are the weakest of the scored parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

A TSI near 46 places Boy Bay Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Boy Bay Lake ranks 100 of 132 in Cass County — at the lower end of the locally monitored distribution.

Zebra mussel presence at Boy Bay Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. The state fisheries records do not list documented species for Boy Bay Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. Public access is available — the lake is on the Minnesota PCA public-access list. The lake has a long ice-out record — 71 observations on file, with a median ice-out around Apr 28. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.