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Science & Nature • Invasive Species

Zebra Mussel

The zebra mussel (*Dreissena polymorpha*) is a small freshwater bivalve native to parts of Eurasia and widely recognized as an invasive species in North America.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

The zebra mussel (Dreissena polymorpha) is a small freshwater bivalve native to parts of Eurasia and widely recognized as an invasive species in North America. It spreads mainly through ballast water and overland transport on boats and equipment, where it can clog pipes, outcompete native species, and alter aquatic ecosystems.

Description

Zebra mussels are small bivalve molluscs with a distinctive striped shell. They are freshwater species that attach to hard underwater surfaces and can survive transport between water bodies on boats, trailers, and gear.

Distribution and invasion history

The species is native to Eurasia and became established in North America after arriving in the Great Lakes region in the late 1980s. From there, it spread widely through connected waterways and human-assisted movement.

Ecological and economic impacts

Zebra mussels filter large amounts of water, which can reduce plankton and affect native species and food webs. They also clog pipes and water-intake infrastructure, creating costly maintenance problems.

Management and prevention

Control efforts focus on preventing spread, especially by cleaning boats and equipment and avoiding movement of untreated water. In industrial systems, mechanical cleaning and chemical treatments are used in some settings.

Key facts

  • Zebra mussels are small freshwater molluscs with striped, D-shaped shells.
  • They are native to Eurasia, especially the Caspian and Black Sea regions.
  • They were introduced to North America in the 1980s, most likely through ship ballast water.
  • They attach strongly to hard surfaces underwater and can spread on boats and equipment.
  • Their filter-feeding can reduce plankton and disrupt aquatic food webs.
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Canadian context

Zebra mussels are a major invasive species concern for Canadian waterways, especially in Ontario, Quebec, Manitoba, and the Great Lakes basin. They are a cross-border management issue because they affect fisheries, recreation, and water infrastructure in Canada and the United States.

Frequently asked questions

What is a zebra mussel?
A zebra mussel is a small freshwater bivalve mollusc known for its striped shell and invasive behavior in many regions outside its native range.
Where are zebra mussels native to?
They are native to Eurasia, particularly the Caspian and Black Sea regions.
How did zebra mussels reach North America?
They were likely introduced in ship ballast water and first detected in the Great Lakes in 1988.
Why are zebra mussels a problem?
They clog pipes and other infrastructure, attach to hard surfaces in dense colonies, and can disrupt native aquatic ecosystems by outcompeting other species and reducing food supplies.
Are zebra mussels found in Canada?
Yes. Canadian sources describe zebra mussels as invasive to all of Canada.
How can zebra mussels be spread to new lakes?
They can be spread on boats, trailers, fishing gear, and other equipment, especially if water or attached mussels are moved between water bodies.

References

  1. Fisheries and Oceans Canadahttps://www.dfo-mpo.gc.ca/species-especes/profiles-profils/zebramussel-moulezebree-eng.html
    Supports: States that zebra mussels are freshwater hinged mollusks and invasive to all of Canada.
  2. National Invasive Species Information Centerhttps://www.invasivespeciesinfo.gov/aquatic/invertebrates/zebra-mussel
    Supports: Gives the scientific name, native range, U.S. introduction date, and introduction pathway.
  3. National Park Servicehttps://www.nps.gov/articles/zebra-mussels.htm
    Supports: Describes zebra mussels as freshwater bivalves likely introduced in ship ballast water and native to the Caspian and Black Sea region.
  4. Invasive Species Centrehttps://www.invasivespeciescentre.ca/invasive-species/meet-the-species/fish-and-invertebrates/zebra-and-quagga-mussels/
    Supports: Describes North American spread, impacts on plankton, water intake lines, beaches, and spread on boats.
  5. Minnesota Department of Natural Resourceshttps://www.dnr.state.mn.us/invasives/aquaticanimals/zebramussel/index.html
    Supports: Provides shell description, size, introduction history, and impacts on equipment and infrastructure.