Overview
If this shellfish invades it could reduce the number of different clam and bivalve species in our marine environment. It inhabits a wide range of substrate types, temperature and salinity gradients and may reach population densities of more than 25,000/m2.

The native range of this clam is China, Japan and Korea although it has now invaded parts of the west coast of the United States.

Mode of distribution
The young Asian clams can travel here in a boat's ballast water while the adults can attach to fishing equipment and can invade as fishing vessels move around the world.

Description
Size: Generally 2-3 cm in length. Can be as small as 0.5 cm.

Visibility: Normally 1/2 - 2/3 of the shell is exposed above the substrate.

Colour: Dirty white (white, tan or yellow).

Key features
This clam has a smooth unsculptured shell. One of the clam's two shells is slightly longer than the other, causing the clam to have a slight overbite. The portion of the shell exposed above the surface of the sediment is generally brown in colour because of sediment that has adhered to the outside of the shell. Sometimes barnacles or other similar organisms can also stick to the exposed portion of the shell.

Action plan
Asian clam action plan September 2001 (PDF 360KB).

(You'll need Adobe Acrobat Reader to read the PDF files; it's available to download for free. It may take a while to download.)