Zebra mussel

Zebra mussels clustered in a group

 Alexander Hardy

Common names
Zebra mussel
Latin name
Dreissena polymorpha

Potential threat

Where introduced, zebra mussels threaten native fish and wildlife by consuming available food and smothering native species. They clog power plant and other water intakes, costing taxpayers millions of dollars.

How you can help

WDFW has initiated volunteer monitoring programs in several lakes, and along the Columbia and Snake rivers, and requires that out-of-state participants in fishing contests undergo boat inspections. WDFW is increasing boater education efforts,and inspections of privately hauled recreational boats being transported from out of state. It is important that recreational boaters and anglers clean their boats and equipment before moving from one waterbody to another.

Description and Range

Physical description

Usually the zebra mussel is about the size of an adult fingernail, but can be as large as two inches, or as small as a sesame seed. Because the mussels can live out of water for up to a month – if they are not subjected to heat or extreme drying conditions – they may be easily transported on recreational boats. They can be on aquatic plants attached to boats or trailers, or as microscopic larvae in bilges, live wells, motor cooling systems and other water systems, or attached to the hulls, especially around trim tabs, transducers, keels or propellers

Geographic range

Zebra mussels are native to the Caspian Sea, and were introduced into the Great Lakes in the mid-1980s in ships’ ballast water. Zebra mussels have since spread to more than 30 states as well as Canada, but have not yet been found in Washington.

Invasive Species

Invasive species classification
Invasive species family