Discovery Bay beaches on the Strait of Juan de Fuca and some on the west side of the Strait in Clallam County have been closed to recreational harvesting of shellfish because of dangerous levels of paralytic shellfish poisoning found in samples.
Commercially harvested shellfish are sampled separately, and products on the market should be safe to eat, said Frank Cox, marine biotoxin coordinator for the state Department of Health, on Tuesday.
The Discovery Bay beaches were closed Monday after 113 micrograms of paralytic shellfish poisoning — also known as PSP or red tide — per 100 grams of shellfish tissue were found in blue mussels at Beckett Point, Cox said.
The closure is the first this year because of PSP, Cox said.
“Discovery’s been quiet up until now,” he said.
Also closed to recreational shellfish harvesting are beaches on the Strait from Low Point near the Lyre River westward to Cape Flattery.
Those closures were prompted by the discovery of 83 micrograms of PSP per 100 grams of tissue found in a California mussel at Sekiu Point last week.
The action limit for paralytic shellfish poisoning is 80 micrograms per 100 grams of tissue.
The Discovery Bay closure area boundaries are from north of Cape George south to include all of Discovery Bay and northwest to about one mile west of Diamond Point to Rocky Point in Clallam County.
Warning signs have been posted at high-use beaches warning people not to collect shellfish from these areas.
The closure includes clams, oysters, mussels, scallops and other species of molluscan shellfish.
Some beaches — from Green Point to Low Point and on Sequim Bay — are closed only to butter clam harvesting.
“That’s toxin from last year,” Cox said, explaining that “butter clams can hold onto the toxin for a very long time.”
On Friday, several sites in the San Juans went over the limit, Cox said.
PSP, or red tide, tends to be a warm-weather occurrence.
“Plankton grows just like the lawn,” Cox said.
“When it’s got sunshine and nutrients, it grows.”
Dangerous levels generally are found from June through September, with the highest usually in September, Cox said.
Last year, levels were very high on many beaches along the Strait and Puget Sound.
Cox said that in 2010, samples at 26 sites — including sites on the North Olympic Peninsula — contained more than 1,000 micrograms of toxin per 100 grams of tissue.
Is it likely to get that bad this year?
“I just don’t know,” Cox said.
“We can’t count on it behaving in any predictable pattern.
“The most predictable thing I can say about it is that it is unpredictable.
“We just have to be continually vigilant.”
Samples are tested every two weeks unless a dangerous level of toxin has been found, when weekly testing is initiated.
Marine biotoxins are not destroyed by cooking or freezing and can be life-threatening.
Symptoms of PSP can appear within minutes or hours and usually begin with tingling lips and tongue, moving to the hands and feet, followed by difficulty breathing and potentially death.
In most cases, the algae that contain the toxins cannot be seen and must be detected using laboratory testing.
Recreational shellfish harvesters can check the state Department of Health website at http://tinyurl.com/y9uv6q9 or phone 800-562-5632.
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Managing Editor/News Leah Leach can be reached at 360-417-3531 or leah.leach@peninsuladailynews.com.