The state Health Department found unsafe levels of the marine biotoxins that cause diarrhetic shellfish poisoning. The condition can cause diarrhea, nausea, vomiting, abdominal cramps and chills.
Shellfish harvested commercially are tested for toxins prior to distribution and should be safe to eat.
The closure includes clams, oysters, mussels, scallops and other species of shellfish, but not shrimp or crab.
Sequim Bay is also closed due to the risk of diarrhetic shellfish poisoning.
Elsewhere, beaches on the Strait of Juan de Fuca from Cape Flattery east to Dungeness Spit are open to shellfish harvesting except for butter and varnish clams, which retain toxins for up to a year.
Marine biotoxins are not destroyed by cooking or freezing.