The Washington State Department of Health closed all Quartermaster Harbor beaches to recreational shellfish harvesting last week after unsafe levels of Paralytic Shellfish Poison (PSP) were detected in harbor shellfish on Vashon-Maury Island. Unsafe levels of a second toxin, Diarrhetic Shellfish Poison, was also found in shellfish in Dockton.
The closure includes all species of shellfish including clams, geoduck, scallops, mussels, oysters, snails and other invertebrates — the closure does not include crab or shrimp. Crab meat is not known to contain the PSP toxin, but the guts can contain unsafe levels. To be safe, clean crab thoroughly and discard the guts or “butter.”
Commercial beaches are sampled separately, and commercial products should be safe to eat.
Naturally occurring microscopic algae produces the toxins, which cannot be destroyed by cooking or freezing. Anyone who eats PSP-contaminated shellfish is at risk for illness and PSP poisoning can be life-threatening: Symptoms of PSP usually begin 30-60 minutes after eating contaminated shellfish, but can take several hours. Symptoms generally begin with numbness or tingling of the face, arms, and legs. This is followed by headache, dizziness, nausea and loss of muscle coordination. In cases of severe poisoning, muscle paralysis and respiratory failure occur, and in these cases death may occur in two to 25 hours. PSP can only be detected by laboratory testing.
Typically beaches/waters are sampled every two weeks in the area, however once unsafe levels of toxins are detected, testing occurs weekly.
See https://fortress.wa.gov/doh/eh/maps/biotoxin/biotoxin.html for up-to-date information on closures.