All of King County and most of the eastern portion of Kitsap County in Washington state have been closed to shellfish gathering after tests this week revealed the presence of toxins that can cause paralytic shellfish poisoning.

Recreational harvest of everything from geoducks, butter and razor clams to oysters, mussels, snails and scallops are shut down until further notice, according to the Washington State Department of Health. Workers with Public HealthÂ-Seattle & King County plan to post warning signs along area beaches.

The closures are not unusual. The foggy overcast mornings and hotter afternoons have helped set up perfect conditions for blooms of microscopic marine organisms that release potentially deadly neurotoxins.

"If this weather pattern continues, I think the sites that are toxic will probably become more toxic and new sites, maybe all the way down into Pierce County, will join them," said Frank Cox, with the shellfish program at the Washington State Department of Health. "All we can do is monitor, watch and wait and see."

The toxins that cause paralytic shellfish poisoning get sucked up by filter-feeding shellfish and can sicken and in some cases kill people. Only some of the neurotoxins produce "red tides," and not all red tides are harmful. The toxins can't be seen, and can't be killed by cooking or freezing.

(c) 2011, The Seattle Times.

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