Starry Stonewort
Invasive SpeciesFound in 95 lakes
Starry stonewort is a relatively new invasive macroalga in the region. It forms thick, hard-to-control mats and is much more difficult to remove than the older invasive plants. Documented in 95 lakes so far — a number that has grown over the past five years. 95 infested lakes is enough to require active prevention work statewide. The species is established in pockets but not ubiquitous.
The presence of Starry Stonewort does not directly change a lake's letter grade — the grade measures the water itself, not the species living in it. Invasive presence is still worth reading alongside the grade.
Lakes with Starry Stonewort
| Lake | County | State | Grade | Depth |
|---|---|---|---|---|
| Clearwater Lake | Wright | MN | A | 73 ft |
| Long Lake | Kandiyohi | MN | A | 46 ft |
| Long Lake | Hubbard | MN | A | 135 ft |
| Benedict Lake | Hubbard | MN | A | 91 ft |
| Leech Lake | Cass | MN | A | - |
| Moose Lake | Beltrami | MN | A | 71 ft |
| Turtle Lake | Beltrami | MN | A | 45 ft |
| Pokegama Lake | Itasca | MN | A | 112 ft |
| West Sylvia Lake | Wright | MN | A | 97 ft |
| Pleasant Lake | Wright | MN | A | 74 ft |
| Bemidji Lake | Beltrami | MN | A | 76 ft |
| Rush Lake | Crow Wing | MN | A | 105 ft |
| Wolf Lake | Beltrami | MN | A | 57 ft |
| Thunder Lake | Cass | MN | A | 95 ft |
| Stump Lake | Beltrami | MN | A | 24 ft |
| Three Island Lake | Beltrami | MN | A | 25 ft |
| Beltrami Lake | Beltrami | MN | A | 50 ft |
| Minnewaska Lake | Pope | MN | A | 32 ft |
| Garfield Lake | Hubbard | MN | A | 32 ft |
| Middle Cullen Lake | Crow Wing | MN | A | 48 ft |
| Pimushe Lake | Beltrami | MN | A | 40 ft |
| Steamboat Bay Lake | Cass | MN | A | 150 ft |
| Boy Bay Lake | Cass | MN | A | - |
| Shingobee Bay Lake | Cass | MN | A | - |
| Portage Bay Lake | Cass | MN | A | - |
| Traders Bay Lake | Cass | MN | A | - |
| Headquarters Bay Lake | Cass | MN | A | - |
| Sucker Bay Lake | Cass | MN | A | - |
| Walker Bay Lake | Cass | MN | A | - |
| Agency Bay Lake | Cass | MN | A | - |
| Kabekona Bay Lake | Cass | MN | A | 150 ft |
| Hen Lake | Crow Wing | MN | A | 105 ft |
| Cass Lake Allens Bay | Beltrami | MN | A | 120 ft |
| Cass Lake | Beltrami | MN | A | 120 ft |
| Big Cedar Lake-North Site-Near West Bend | Washington | WI | A | 105 ft |
| Big Cedar Lake-South Site-Near West Bend | Washington | WI | A | 105 ft |
| Okauchee Lake | Waukesha | WI | A | 90 ft |
| Geneva Lake | Walworth | WI | A | 135 ft |
| Big Wolf Lake | Hubbard | MN | B | 57 ft |
| Green Lake | Walworth | WI | B | 57 ft |
| Green Lake | Washington | WI | B | 37 ft |
| Silver Lake | Kenosha | WI | B | 44 ft |
| Bear Lake | Waupaca | WI | B | 62 ft |
| Pike Lake | Washington | WI | B | 45 ft |
| Pewaukee Lake | Waukesha | WI | B | 45 ft |
| Grass Lake | Shawano | WI | B | 52 ft |
| Lac la Belle Lake | Waukesha | WI | B | 45 ft |
| Eagle Spring Lake | Waukesha | WI | B | 8 ft |
| Lower Nemahbin Lake | Waukesha | WI | B | 36 ft |
| Denoon Lake | Waukesha | WI | B | 55 ft |
Showing 50 of 95 infested lakes.
Frequently Asked Questions
How many lakes have starry stonewort?
Starry Stonewort has been documented in 95 graded lakes: 58 in Minnesota, 37 in Wisconsin.
Does starry stonewort affect water quality?
Invasive species can significantly affect lake ecosystems. They may alter nutrient cycling, displace native species, and change water clarity. Lakes with starry stonewort should be monitored for changes in water quality over time.
Invasives Found With Starry Stonewort
Co-occurs in 45 lakes · 667 total
Co-occurs in 36 lakes · 420 total
Co-occurs in 35 lakes · 667 total
Co-occurs in 23 lakes · 494 total
Co-occurs in 20 lakes · 275 total
Co-occurs in 18 lakes · 362 total
More on invasive species and lake health
Zebra mussel counts from the lakes LakeQuality grades, the counties that show up most often, and the Clean, Drain, Dry rules that still matter.
How lakes are graded A–F on nutrients and algae using EPA ecoregion condition classes, what each letter means in the water, and why an A is not a clearance.
Before you buy lakefront, check the water: clarity trend, nutrient impairment, algae advisories, invasive species, and depth — a data-backed checklist.
Source: EPA National Aquatic Resource Surveys, 2026.