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Lobster Lake reads lower on nutrients and algae than Red Rock Lake. Both are in Douglas County, Minnesota.

Reviewed by LakeQuality Editorial Team · Updated

Lobster Lake and Red Rock Lake are both in Minnesota — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The readings are meaningfully apart: Lobster Lake carries clearly lower phosphorus and chlorophyll-a readings than Red Rock Lake. A spread that wide reflects real underlying differences, in watershed inputs, depth profiles, or monitoring rigor.

For a recreational visitor, the wider gap in the readings is decisive: Lobster Lake has the lower nutrient and algae numbers. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?

Lobster Lake

Douglas County, Minnesota

Good clarity, visible to about 13 ft.

Red Rock Lake

Douglas County, Minnesota

Murky, only visible to about 3.6 ft.

Side-by-Side Metrics

MetricLobster LakeRed Rock Lake
Water Clarity13 ft Better3.6 ft
Phosphorus20.5 µg/L Better55 µg/L
Chlorophyll-a (Algae)3.6 µg/L Better33.7 µg/L
Maximum Depth65 ft Better22 ft
Surface Area1,334 acres904 acres
Public AccessYesYes
Fish Species18 Better13
Trophic Statemesotrophiceutrophic

A green ✓ marks the better value for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better). Surface area and trophic state carry no tick — a bigger lake is not a better lake.

Verdict

Lobster Lake reads lower on nutrients and algae than Red Rock Lake. Water clarity: 13 ft vs 3.6 ft. For fishing diversity, Lobster Lake also leads with 18 species.

Source: EPA National Aquatic Resource Surveys, 2026.