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Zebra and Quagga Mussels

Zebra and Quagga Mussels

Zebra and Quagga Mussels

(Dreissena polymorpha and Dreissena rostriformis bugensis)

Tags: Aquatic

Identification and Reproduction


  • Zebra mussels grow up to 15 mm in size and have a “D-shaped” shell that can lay flat on surfaces. 
  • Their colour may vary from light to dark brown and the shell has obvious “zebra” striping.
  • Quagga mussels grow up to 20 mm in size. Its shell is rounder in shape than the zebra mussel and does not sit flat. 
  • The color of the quagga shell is pale near its hinge and usually features dark, concentric rings.
  • These two muscles share (which our native mussels do not have) are their tough byssal threads are strong, sticky fibers that certain mollusks (including some mussels) use to attach themselves to rocks and other surfaces.


  • Both Zebra and Quagga are dioecious, which means male and female reproductive organs are in separate individuals.
  • Males and females release their eggs and sperm simultaneously into the water, where they become fertilized and develop into microscopic larvae.
  • They can produce about one million eggs in a spawning season.

Habitat & Ecology

  • Zebra and quagga mussels will grow very quickly and cover a surface, they tend to be found in areas with high boat activity (ie. dock pilings, nearby buoys)
  • In cool and moist environments, Zebra and quagga mussels can survive for several weeks without being immersed in water.


  • They can clog pipes of water treatment and power plants, disrupt ecosystems with large monocultures, are difficult to remove and non-native to British Columbia.
  • Pose a serious threat to the biodiversity and fisheries of any water system.
  • They can upset the balance of algae in an area, resulting in a higher concentration of blue-green algae and become toxic to aquatic life
  • There two mussels can cause taste and odor problems in drinking water supplies, and can be very unpleasant for recreational users.
  • Their sharp shells will wash up on beaches and make it painful to walk barefoot.


  • Learn how to identify zebra and quagga mussels and how to prevent accidentally spreading these invasive species.
  • Inspect your boat, trailer and equipment after each use. Remove all plants, animals and mud before moving to a new water body.
  • Drain water from motor, live well, bilge and transom wells while on land.
  • Clean all recreational equipment with a high pressure wash, hot water, OR let it dry in the sun for at least 5 days.