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Bass Lake reads lower on nutrients and algae than Island Lake. Both are in Mahnomen County, Minnesota.

Reviewed by LakeQuality Editorial Team · Updated

Bass Lake and Island 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. Bass Lake reads materially cleaner than Island Lake on nutrients and algae. A gap that wide is unlikely to close in a single year of remediation work; it reflects multi-decade differences in the lakes themselves.

For a recreational visitor, the wider gap in the readings is decisive: Bass 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?

Bass Lake

Mahnomen County, Minnesota

Good clarity, visible to about 13.1 ft.

Island Lake

Mahnomen County, Minnesota

Murky, only visible to about 4.5 ft.

Side-by-Side Metrics

MetricBass LakeIsland Lake
Water Clarity13.1 ft Better4.5 ft
Phosphorus10 µg/L Better30 µg/L
Chlorophyll-a (Algae)4.9 µg/L Better34.3 µg/L
Maximum Depth26 ft43 ft Better
Surface Area735 acres616 acres
Public AccessYesYes
Fish Species13 Better11
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

Bass Lake reads lower on nutrients and algae than Island Lake. Water clarity: 13.1 ft vs 4.5 ft. For fishing diversity, Bass Lake also leads with 13 species.

Source: EPA National Aquatic Resource Surveys, 2026.