Blackduck Lake vs Gull Lake
Water quality, depth, fish species, and recreation comparison.
Blackduck Lake and Gull Lake read the same on nutrients and algae. Both are in Beltrami County, Minnesota.
Blackduck Lake and Gull 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. These two sit close on the readings, Blackduck Lake versus Gull Lake. The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.
With readings this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Blackduck Lake
Murky, only visible to about 6.2 ft.
Gull Lake
Moderate clarity, visible to about 7.9 ft.
Side-by-Side Metrics
| Metric | Blackduck Lake | Gull Lake |
|---|---|---|
| Water Clarity | 6.2 ft | 7.9 ft Better |
| Phosphorus | 34 µg/L | 26 µg/L Better |
| Chlorophyll-a (Algae) | 12.3 µg/L | 6.3 µg/L Better |
| Maximum Depth | 28 ft Better | 23 ft |
| Surface Area | 2,711 acres | 2,256 acres |
| Public Access | Yes | Yes |
| Fish Species | 16 Better | 13 |
| Trophic State | eutrophic | mesotrophic |
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.
Swap a lake
Compare Blackduck Lake or Gull Lake against a different lake.
Verdict
Both lakes earn the same Grade C. The tiebreakers come down to clarity (Blackduck Lake: 6.2 ft, Gull Lake: 7.9 ft) and what you want from the lake. Blackduck Lake supports more documented fish species.
Source: EPA National Aquatic Resource Surveys, 2026.