[3] This species of mollusc was exploited by early humans in North America; for example, the Chumash peoples of Central California harvested these clams in Morro Bay approximately 1,000 years ago,[4] and the distinctive shells form middens near their settlements.

It usually occurs in protected areas on sand, hard mud and clayey-gravel substrates from the mid and lower shore down to depths of about 10 m (33 ft), usually buried less than 8 cm (3 in) beneath the surface of the sediment.

[7] It is clear that PSP-causing toxin levels are typically much higher in the summer months[9] though this does not mean the seafood is necessarily safe at other times.

[10] Risks also vary based on species[7][8] but seafood available for retail sale is required to meet the FDA standards.

[12] This transformation to decarbomyl derivative has been reported in some other clam species and significantly reduces the toxicity of saxitoxins present.

[13] Predators include such molluscs as the leafy hornmouth snail (Ceratostoma foliatum) and Lewis's moon snail (Neverita lewisii), the crabs Metacarcinus magister and Cancer productus, the giant Pacific octopus (Enteroctopus dofleini) and the sea otter.