The Purple Varnish Clam is a Northwest newcomer. It's not clear yet how this fast-spreading bivalve may affect other marine creatures.

Biologists first noticed the Purple Varnish Clam near Vancouver Island in the late 1980's. It's native to Japan and Korea and probably came to North America in ballast water. Large ships use tanks of seawater to give them stability and then pump it out when taking on cargo. Small clams and other creatures can be taken in with the sea water and end up being released into the environment at the other end of the voyage.

Since its arrival in North America, the Purple Varnish Clam has spread south to Puget Sound and along the Pacific Coast. Its flattish brown shell grows to 2 1/4 inches across with a varnished shine outside and a purple interior. It lives in shallow water, especially near freshwaters seeps, and can quickly dig itself 8 inches deep into sand or gravel. At night the clam extends two long tubes to just above the sea floor; one takes in water from which the clam filters food and the other sends out waste. Unlike many other clams, this one can also feed as it moves along. A single, muscular foot propels it, and as bits of food stick to the foot, the clam transfers them to its mouth.

With a shellfish license you can harvest Purple Varnish Clams, but it's important to check first that they're safe to collect where you plan to go. These clams concentrate toxins at higher levels than other types and hold onto the toxins longer. Call the Shellfish Safety Hotline: 1-800-562-5632.