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LakeQuality
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Zebra Mussel

Invasive speciesRecorded in 609 lakes

Zebra mussels are the most consequential invasive in the upper Midwest lake system. They are small, fast-reproducing bivalves that filter enormous volumes of water, increase clarity in a misleading way (filtered water reads clearer on a Secchi disk), and disrupt the food web by stripping the planktonic base. A 609-lake footprint means Zebra Mussel prevention has shifted from "stop the spread" to "manage the new normal." Watercraft-inspection programs at boat launches and shoreline-management practices on individual lakes are doing most of the active prevention work.

A lake with zebra mussels can read clearer on the Secchi disk than its nutrient regime would suggest, because the mussels, not low phosphorus, produce that clarity. Reading the clarity number and the invasive flag together gives a truer picture.

609
Lakes with records
458
Minnesota
151
Wisconsin

Lakes with Zebra Mussel

LakeCountyStateDepth
Lobster LakeDouglasMN65 ft
Clearwater LakeWrightMN73 ft
Lower Hay LakeCrow WingMN100 ft
Latoka LakeDouglasMN108 ft
Little Birch LakeToddMN89 ft
North Long LakeCrow WingMN97 ft
Mud LakeBeckerMN34 ft
Big LakeBeltramiMN35 ft
Big LakeSherburneMN48 ft
Pelican LakeOtter TailMN55 ft
Pelican LakeCrow WingMN104 ft
Round LakeAitkinMN125 ft
Round LakeCrow WingMN51 ft
Whitefish LakeCrow WingMN138 ft
Horseshoe LakeCrow WingMN56 ft
Long LakeKandiyohiMN46 ft
Long LakeOtter TailMN128 ft
Long LakeBeckerMN61 ft
Long LakeHubbardMN135 ft
Long LakeOtter TailMN73 ft
Dead LakeOtter TailMN65 ft
Maple LakeDouglasMN78 ft
Detroit LakeBeckerMN89 ft
Sallie LakeBeckerMN50 ft
Deer LakeOtter TailMN26 ft
Chippewa LakeDouglasMN95 ft
Lida LakeOtter TailMN58 ft
Cowdry LakeDouglasMN52 ft
Ossawinnamakee LakeCrow WingMN63 ft
Florida LakeKandiyohiMN40 ft
Clear LakeCrow WingMN63 ft
Spectacle LakeIsantiMN51.5 ft
Marion LakeDakotaMN21 ft
Eagle LakeHubbardMN77 ft
Eagle LakeKandiyohiMN67 ft
Eagle LakeOtter TailMN46 ft
Darling LakeDouglasMN62 ft
Ida LakeDouglasMN106 ft
Ida LakeBeckerMN20 ft
Star LakeOtter TailMN94 ft
Upper Maple LakeWrightMN76 ft
Fish LakeOtter TailMN69 ft
Benedict LakeHubbardMN91 ft
Sand LakeItascaMN60 ft
Little Pine LakeCrow WingMN36 ft
Woman LakeCassMN-
Andrusia LakeBeltramiMN60 ft
Green LakeKandiyohiMN110 ft
Girl LakeCassMN81 ft
Upper Gull LakeCassMN54 ft

Showing 50 of 609 lakes with a record.

Frequently Asked Questions

How many lakes have zebra mussel?

Zebra Mussel is recorded in 609 measured lakes: 458 in Minnesota, 151 in Wisconsin. 609 of them carry a state infested-waters listing or an established population.

Does zebra mussel affect water quality?

An established invasive population can change how a lake works — altering nutrient cycling, displacing native species, and shifting water clarity. Clarity is the one to watch: filter-feeders can make water read clearer on a Secchi disk without any drop in nutrient loading, so a lake with zebra mussel is worth reading alongside its clarity number rather than through it.

Invasives Found With Zebra Mussel

Eurasian Watermilfoil

Co-occurs in 142 lakes · 792 total

Curly-Leaf Pondweed

Co-occurs in 113 lakes · 387 total

Banded Mystery Snail

Co-occurs in 73 lakes · 341 total

Chinese Mystery Snail

Co-occurs in 60 lakes · 469 total

Purple Loosestrife

Co-occurs in 59 lakes · 242 total

Starry Stonewort

Co-occurs in 41 lakes · 79 total

More on invasive species and lake health

Zebra Mussel Spread: How Many Lakes Are Affected?

Zebra mussel counts from the lakes LakeQuality tracks, the counties that show up most often, and the Clean, Drain, Dry rules that still matter.

Lake Water Quality Explained: What the Readings Mean

How nutrient and algae readings are read against EPA ecoregion condition classes, what each class means in the water, and why a clean reading is not a clearance.

What to Check Before Buying Lakefront Property

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.