Zebra and Quagga Mussel Facts

Clean, dry and drain your watercraft to help stop the spread of invasive mussels.

Invasive mussels in B.C.

Quagga mussels and zebra mussels are not native to North America. They were introduced from Europe into Canada (the Great Lakes region) and the United States in the 1980s. Since their introduction, these mussels have spread in Ontario and Quebec and they are now found in at least 24 American states as far west as California. In October 2013, zebra mussels were discovered in Lake Winnipeg, Manitoba.


These small, freshwater mussels can easily attach themselves to boat hulls, trailers, motors, equipment, vegetation and other organisms. They multiply rapidly and are extremely difficult to eradicate once they become established in an area. In larger water bodies and complex ecosystems they may be impossible to eradicate unless detected and contained before they become established.

Zebra and quagga mussels can survive for several weeks without being immersed in water if they are left in a cool and moist environment, so mussels attached to boats or equipment can be transferred from one body of water to another.‚Äč

Threat to B.C.

Quagga and zebra mussels pose a serious threat to B.C.’s aquatic ecosystems, salmon populations, hydro power stations and other infrastructure facilities. They can clog pipes (increasing maintenance costs for hydroelectric, industrial, agricultural and recreational facilities), cause ecological and economic damage, displace native aquatic plants and wildlife, degrade the environment and affect drinking water quality.

The economic impact of these invasive mussels to hydropower, agricultural irrigation, municipal water supplies and recreational boating has been estimated to be $43 million per year. This estimate does not include additional impacts on commercial and recreational fisheries.

To date, there has been no reported introduction of live quagga or zebra mussels into B.C. lakes or waterways. Zebra and quagga mussels are not established in British Columbia, Alberta, Saskatchewan, Oregon, Idaho, Washington or Montana.

How to Identify Zebra and Quagga Mussels

Distinguishing features of Zebra and Quagga Mussels:

  • Small only up to 3 cm / 1 inch

  • Form dense clumps attached to hard surfaces

  • Propeller blade shaped

  • Zebra stripes often but not always present

Native Mussels and clams:

  • Most species' adults are far larger than zebra and quagga mussels >3 cm/1 inch

  • Either oval or heart shaped

  • Buried, partially buried or on soft substrate or between cobbles

  • Do not form clumps or attach to vertical surfaces

Invasive mussels comparison

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