OLYMPIA – There will be no razor clam opening in November – and possibly for several months – due to the continuing rise of marine toxin levels in coastal waters, the Washington Department of Fish and Wildlife (WDFW) announced today.
Toxicology results released today by the Washington Department of Health (DOH) show that domoic acid levels in clams sampled at all five state razor clam beaches far exceed the threshold deemed safe for human consumption, said Dan Ayres, lead WDFW coastal shellfish biologist.
Oregon beaches have also been closed to razor clam digging since Oct. 10 due to high levels of domoic acid, a naturally occurring marine toxin.
"I'm sorry to say that marine toxin levels on the coast are not only high, but getting higher," Ayres said. "Judging from past experience, it could take a number of months for those toxin levels to subside."
Tests conducted by DOH found toxin levels in clams at all five Washington razor clam beaches well above the federal standard of 20 parts per million (ppm), the threshold above which clams are deemed unsafe for human consumption.
The highest toxin levels in razor clams dug Oct. 20-21 were found at Mocrocks (Iron Springs to Moclips) with 188 ppm, followed by Copalis (185 ppm), Long Beach (132 ppm) and Twin Harbors (113 ppm), said Ayres. Clams at Kalaloch, which will be tested in the next few days, had a domoic acid level of 99 ppm as of Oct. 13.
Ingesting high levels of domoic acid can cause amnesic shellfish poisoning (ASP), producing vomiting, diarrhea, abdominal cramps, dizziness and a variety of other ailments. There is no antidote for ASP and extreme cases can result in death, although Ayres said there have been no known fatalities from ASP in Washington state to date.
DOH, which has the responsibility for monitoring shellfish contamination, has assured the public that all commercially harvested razor clams and other commercial shellfish currently available in the marketplace have been subjected to rigorous testing and are safe for consumption.
But freshly dug razor clams are a different story, Ayres said.
"Amnesic shellfish poisoning is serious business," Ayres said. "We'll let the public know as soon as toxin counts return to safe levels, but we urge people not to dig or eat fresh razor clams until then."
That, unfortunately, could take a while, said Ayres, noting that toxin counts in the most recent samples were all significantly higher than in those taken in early October, when WDFW cancelled the first dig of the season. In 1998, the last time domoic acid levels climbed so high, the entire coastal razor clam season was closed for the year.
"I still hold out hope that we can at least have some digging in spring," Ayres said, "but I definitely can't make any promises at this point."
Ayres said WDFW will continue to send razor clams to DOH for testing every two weeks to monitor toxin levels, which are posted on WDFW's website. In addition, both departments are working with a variety of other state, federal and tribal organizations to gain to gain a better understanding of the plankton blooms that cause marine toxin levels to rise.
Since that joint effort got under way in 1999, the Olympic Region Harmful Algal Bloom (ORHAB) has developed a procedure for testing toxins in marine waters that provides an "early warning system" for the onset of high domoic acid levels.
"Plankton cell counts measured by ORHAB supported the tests done on the clams, themselves," Ayres said. "I don't know whether we'll ever be able to control these harmful marine toxins, but at least we can see them coming."