Starry Stonewort
Invasive SpeciesFound in 99 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 99 lakes so far — a number that has grown over the past five years. 99 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 LakeGrade rubric score — the grade measures the water itself, not the species inhabiting it. But invasive presence is a meaningful adjacent signal worth reading alongside the grade.
Lakes with Starry Stonewort
| Lake | County | State | Grade | Depth |
|---|---|---|---|---|
| Moose Lake | Beltrami | MN | A | 71 ft |
| Pokegama Lake | Itasca | MN | A | 112 ft |
| West Sylvia Lake | Wright | MN | A | 97 ft |
| Rush Lake | Crow Wing | MN | A | 105 ft |
| Thunder Lake | Cass | MN | A | 95 ft |
| Thunder Lake | Cass | MN | A | 95 ft |
| Pokegama Lake | Itasca | MN | A | 112 ft |
| 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 |
| Geneva Lake | Walworth | WI | A | 135 ft |
| Pine Lake | Waukesha | WI | A | 85 ft |
| Geneva Lake | Walworth | WI | A | 135 ft |
| Big Cedar Lake | Washington | WI | A | 105 ft |
| Little Muskego Lake | Waukesha | WI | A | 65 ft |
| Geneva Lake Site B | Walworth | WI | A | 135 ft |
| Long Lake | Kandiyohi | MN | A | 46 ft |
| Long Lake | Hubbard | MN | A | 135 ft |
| Benedict Lake | Hubbard | MN | A | 91 ft |
| Turtle Lake | Beltrami | MN | A | 45 ft |
| Pleasant Lake | Wright | MN | A | 74 ft |
| Bemidji Lake | Beltrami | MN | A | 76 ft |
| Three Island Lake | Beltrami | MN | A | 25 ft |
| Beltrami Lake | Beltrami | MN | A | 50 ft |
| Stump Lake | Beltrami | MN | A | 24 ft |
| Middle Cullen Lake | Crow Wing | MN | A | 48 ft |
| Portage Bay Lake | Cass | MN | A | - |
| Traders Bay Lake | Cass | MN | A | - |
| Tamarack Bay Lake | Cass | MN | A | 69.8 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 |
| Bear Lake | Waupaca | WI | A | 62 ft |
| Green Lake | Walworth | WI | A | 57 ft |
| Lower Nemahbin Lake | Waukesha | WI | A | 36 ft |
| Pine Lake | Shawano | WI | A | 35 ft |
| Upper Nemahbin Lake | Waukesha | WI | A | 60 ft |
| Middle Lake | Walworth | WI | A | 40 ft |
| Okauchee Lake | Waukesha | WI | A | 90 ft |
| Golden Lake | Waukesha | WI | A | 44 ft |
| Taylor Lake | Waupaca | WI | A | 58 ft |
| Leech Lake | Cass | MN | B | - |
| Steamboat Bay Lake | Cass | MN | B | 150 ft |
| Carnelian Lake | Stearns | MN | B | 36 ft |
| Two Rivers Lake | Stearns | MN | B | 63 ft |
| Wolf Lake | Beltrami | MN | B | 57 ft |
| Minnewaska Lake | Pope | MN | B | 32 ft |
Showing 50 of 99 infested lakes.
Frequently Asked Questions
How many lakes have starry stonewort?
Starry Stonewort has been documented in 99 graded lakes: 58 in Minnesota, 41 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 · 688 total
Co-occurs in 40 lakes · 432 total
Co-occurs in 39 lakes · 688 total
Co-occurs in 25 lakes · 493 total
Co-occurs in 22 lakes · 278 total
Co-occurs in 21 lakes · 363 total
Source: EPA National Aquatic Resource Surveys, 2026.