WHATCOM – Marine biotoxins that cause paralytic shellfish poisoning (PSP) have been detected at high levels in shellfish samples collected from Squalicum Harbor, Birch Bay and Semiahmoo Spit.  As a result, the Washington State Department of Health (DOH) has closed all of Whatcom County to the recreational harvest of shellfish. The County Health Department will continue to test local beaches and will notify the public when shellfish are safe to harvest again.  The closure includes clams, oysters, mussels, scallops, geoducks and other species of molluscan shellfish.