SEQUIM — The state Department of Health closed Sequim Bay to shellfish harvesting this week after three people became ill from a marine toxin never seen before in unsafe levels in shellfish in the United States.
The ban for both recreational and commercial harvesting of all types of shellfish in the bay began Monday, and a recall for all commercially sold shellfish from the area during the past two weeks also went into effect, the department said Thursday.
The Health Department has accounted for all recalled shellfish, and it is not on the market, officials said.
Diarrhetic shellfish poisoning — also called DSP — causes nausea, vomiting and other flu-like symptoms that can begin within a few hours of eating tainted shellfish and last up to three days.
It comes from a toxin produced by a type of plankton long-known to live in high concentrations in Sequim Bay, said Frank Cox, marine biotoxin coordinator with the Health Department.
But why it has taken this long for the toxin, prevalent in parts of Europe and recently found in British Columbia waters, to cause illness here remains unclear, he said.
“We have lots of questions and not as many answers as I would like,” Cox said.
“It’s all new, and it’s a work in progress.”
Two boys and a father from the Seattle area came down with the illness after eating Sequim Bay shellfish in June.
They reported it to the Health Department on July 12 and have since recovered.
The report prompted the agency to run tests for the toxin, which found levels exceeding the international standard set by the European Union.
One sample found levels 10 times above the limit of 16 micrograms per 100 grams of shellfish tissue.
Tests were done by a federal Food and Drug Administration lab, Cox said.
“We aren’t even set up to run that test,” he said.
It’s unknown how long the closure will last.
Unlike paralytic shellfish poisoning — or PSP, also known as red tide, which has prompted closure of other beaches on the North Olympic Peninsula — DSP is not life-threatening, Cox said.
High amounts of PSP can cause difficulty breathing and potentially death.
Still, he said, the agency plans to test for the DSP toxin elsewhere in Washington state waters, though where has not been determined.
Cox said his department has monitored the levels of the plankton, dionophysis, that causes the toxin in Sequim Bay for at least the past two years and is stepping up testing of the water in response to the illness.
Hopefully, he said, that will provide some answers.
“There’s so much about this we don’t know,” Cox said.
Unlike bacterial contamination, the toxin DSP is not killed by cooking or freezing, just like PSP.
High levels of PSP prompted the closure in late June of beaches directly on the Strait of Juan de Fuca from Discovery Bay west to Neah Bay to all recreational harvesting of all species of shellfish.
The closure applied only to sport harvesting, not to commercially harvested shellfish, which are sampled separately, health officials have said.
Dungeness Bay is the only beach between Discovery Bay and Neah Bay that remains open to recreational shellfish harvesting.
The June closure excluded Sequim Bay, which was closed at that time only to harvesting of butter clams — which hold on to the toxin for a longer period of time than other shellfish — and Dungeness Bay.
In Jefferson County — in addition to the closure of Discovery Bay — Kilisut Harbor, including Mystery Bay, is closed to butter clam harvest only.
All ocean beaches are in a seasonal closure now.
All species means clams including geoduck, oysters, mussels and other invertebrates such as the moon snail. Crab meat is not known to contain the PSP toxin, but crab guts can contain unsafe levels and must be discarded.
All areas are closed for the sport harvest of scallops.
The closures do not apply to shrimp.
Butter clams have the ability to retain PSP toxin for a very long time — up to a year or more. Areas may be closed for the sport harvest of butter clams when all other species are safe and open.
For more information, phone the Marine Biotoxin Hotline at 800-562-5632 or visit the state website at http://tinyurl.com/4xmftw7.
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Reporter Tom Callis can be reached at 360-417-3532 or at tom.callis@peninsuladailynews.com.