California Aquatic Invasive Species (AIS)
University of California
California Aquatic Invasive Species (AIS)

Invasive Clams, Mussels, Snails, etc.

Asian Clam

Scientific Name

Corbicula fluminea - Visit ITIS for full scientific classification. 



  • Small, light or dark colored clam with distinct ridges.
  • Has a prominent hinge, and no threads.
  • Shell size is less than 2 inches.
  • Green, brown, or yellowish colored shells.
  • Likely to see dry shells if present.
  • Prefer low flow areas with sandy substrates.
  • Primarily found in freshwater.
  • Can tolerate brackish (somewhat salty) water.
  • Usually colonize near shore. 
Invasion Pathways and Distribution
  • Native to Asia, and parts of Africa and Australia.
  • Now widespread throughout the U.S. and California.
  • Possibly introduced in the U.S. as a food item used by Chinese immigrants, and/or unintentionally through the importation of the Giant Pacific oyster from Asia. 
  • Can continue to spread when used as live bait.
  • Visit USGS for a current U.S. distribution map.
Life History
  • Hermaphrodites, and can self-fertilize. 
  • Multiply and reach densities that clog water delivery systems.
  • Filter water, removing plankton needed by native species, and changing water clarity. Microscopic young stages can be transported in water undetected.
  • Can also alter habitat substrates, and outcompete natives for resources.
References and Useful Links

For references by category and links to other useful AIS sites see our LEARN MORE page.

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