This common clam lies on its left side instead of vertically, at a depth of 10-20 cm. It rocks back and forth while digging. The siphons extend out the right side and up to the surface, which are well accomodated by the twist to the right of the shell. The siphons are used to suck debris from the surface of the sediment like a vacuum cleaner. The clams digest mainly diatoms and some flagellates from the sediments. They ingest large quantities of sediment but reject 97% of it, producing copious pseudofeces (photo). Hinton says the clam moves to another location when the sediment in an area has been thoroughly picked over. Predators include the moon snail Polinices lewisii
. The clam was an important food of the coastal Indian tribes and to Chinese immigrants in San Francisco but is little used commercially today because of the debris that is usually in the gut. This species is very hardy and can be found in areas that have very poor circulation, and can live in very soft, silty mud. The pea crab Pinnixa littoralis
or P. faba
may live in the mantle cavity, as may the Nemertean worm Malacobdella grossa
. The species spawns in early summer in Oregon.