Most of Vashon Island is now closed to recreational shellfish harvesting because of unsafe levels of paralytic shellfish poison, which acts quickly and can cause paralysis of the respiratory system and death.
The Seattle-King County Public Health Department posted an alert Friday evening citing information from the Washington State Department of Health (DOH). The marine organisms that produce the toxin are naturally occurring and are sometimes erroneously referred to as a “red tide.” The algae blooms associated with the toxin can be various colors or have no color at all.
Neither cooking nor freezing destroys the poison. It is not possible with visual inspection to determine if an area of water, or the shellfish in it, is contaminated, according to public health officials. The toxin can only be detected with laboratory analysis.
“Paralytic shellfish poison (PSP) has been detected at unsafe levels in shellfish on Vashon Island at Point Vashon and Tramp Harbor,” according to the alert.
“As a result, the Washington State Department of Health has closed Vashon Island, except Quartermaster Harbor, beaches to recreational shellfish harvest.”
The closure applies to all species of shellfish including clams, geoduck, scallops, mussels, oysters, snails and other invertebrates, according to health officials. The closure does not include crab or shrimp. The meat of crabs 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, sometimes called “butter.”
Only recreational shellfish harvesting is covered by the closure. Commercial beaches are sampled separately and commercial products should be safe to eat, according to the Friday alert. Officials are also warning the public not to collect shellfish for any reason during the closure.
Anyone who eats shellfish contaminated with PSP is at risk for illness. Symptoms of PSP usually begin 30 to 60 minutes after eating contaminated shellfish, but may take several hours.
Symptoms are generally mild, and begin with numbness or tingling of the face, arms and legs. This is followed by headache, dizziness, nausea, and loss of muscle coordination. Sometimes a floating sensation occurs.
“In cases of severe poisoning, muscle paralysis and respiratory failure occur, and in these cases death may occur in 2 to 25 hours,” according to the health alert.
“If symptoms are mild, call your health care provider or Washington Poison Center (800-222-1222), and Public Health (206-296-4774). If symptoms are severe, call 911 or have someone take you to the emergency room immediately.”
Recreational shellfish harvesting can be closed due to high levels of PSP at any time. Therefore, harvesters are advised to call the DOH Biotoxin Hotline at 800-562-5632 or visit the Shellfish safety website before harvesting shellfish anywhere in Puget Sound.
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