Lobster Lake vs Red Rock Lake
Water quality, depth, fish species, and recreation comparison.
Lobster Lake has a higher water quality grade (A, Excellent) than Red Rock Lake (F, Very Poor). Both are in Douglas County, Minnesota.
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 grades are meaningfully apart: Lobster Lake grades a A while Red Rock Lake grades a F. That two-letter spread reflects real underlying differences — different watershed inputs, different depth profiles, or different monitoring rigor.
For a recreational visitor, the wider grade gap is decisive — Lobster Lake is the better water-quality choice. 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
Good clarity, visible to about 13 ft.
Red Rock Lake
Murky, only visible to about 3.6 ft.
Side-by-Side Metrics
| Metric | Lobster Lake | Red Rock Lake |
|---|---|---|
| Overall Grade | A (Excellent) | F (Very Poor) |
| Water Clarity | 13 ft | 3.6 ft |
| Phosphorus | 20.5 µg/L | 55 µg/L |
| Chlorophyll-a (Algae) | 3.6 µg/L | 33.7 µg/L |
| Maximum Depth | 65 ft | 22 ft |
| Surface Area | 1,334 acres | 904 acres |
| Public Access | Yes | Yes |
| Fish Species | 18 | 13 |
| Trophic State | mesotrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Lobster Lake wins on overall water quality with a Grade A versus Red Rock Lake's Grade F. 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.