Species Information

Zebra (left) and quagga mussels Zebra (left) and quagga mussels
USGS
Zebra (left) and quagga mussels
USGS
Zebra mussel
Dreissena polymorpha

  Click here for information at USGS!

  Click here for a quick guide for this species. PDF format!

  Click here for a quick species card. PDF format!

Similar Species
  • Quagga mussel Dreissena bugensis

History
  • Believed to be introduced to the Great Lakes during ballast water exchange from a cargo ship from the Black Sea
  • Since being discovered in Great Lakes in 1988, the species has spread widely into freshwater habitats across North America
  • Native to Black, Caspian, and Azov Seas

Characteristics
  • Named for the striped pattern on its shell - Black or brownish shell with cream or white stripes
  • Shells colors vary widely; some pale or completely white
  • Maximum size less than 2 in (5 cm) long; often less than 1 in
  • Zebra shell is stable when placed on it's flattened hinge side while quagga mussels, lacking a flat side, fall over
  • Valves (shell halves) are symmetrical, forming a straight line when closed whereas the quagga mussel valves are asymmetrical, forming a curved line when the valves are closed

 


Habitat
  • Lakes, estuaries, streams
  • Attached to hard surfaces such as rocks, wood, and plants and to manmade structures of concrete, metal, and fiberglass
  • Tolerate salinity to 6 ppt, temperatures to approximately 29 degrees C

Known Distribution in the Northeast
  • 21 states and 2 provinces including Quebec, New York, Vermont, Massachusetts, and Connecticut 

Impacts
  • Voracious filter feeders, removing microscopic plants and animals from the water, reducing food available to other aquatic animals
  • May cause declines in fish populations
  • Clog intakes for power plants, industrial facilities, and public drinking water supplies
  • Foul boat and ship hulls
  • Economic impacts in the billions of dollars

Zebra mussels (Dreissena polymorpha)
Whitney Cranshaw, Colorado State University