Hunt is on for deadly neurotoxin that can contaminate shellfish

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by GLENN FARLEY - KING 5 News

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KING5.com

Posted on January 31, 2012 at 7:04 PM

PUGET SOUND -  You have to go back to the 1940s to find anybody who died from paralytic shellfish poisoning in Washington state, says NOAA biological oceanographer Stephanie Moore.  Work by the shellfish industry and county and state health departments have made eating shellfish a safe bet here. 

But she says since the late 1950s there is growing concern than an age old neurotoxin that can cause everything from tingling fingertips to complete muscle paralysis is a growing threat.

"We have very little warnings of these blooms," said Moore.  

Moore is one of the principle investigators for a joint study by the University of Washington and the National Oceanic and Atmospheric Administration  into the underlying risks from a one celled algae called Alexandrium.  It's an algae that swims with a small whip like tail, part of a class of organisms known as a dinoflagellates.  They are tiny, invisible unless they are clumped together in chains, and then still hard to see.  Filter feeding shellfish like mussels, clams and oysters eat them, and if there are a lot of Alexandrium around in an algae bloom,  the shellfish concentrate the neurotoxins to produce into a potentially lethal dose for humans.  The shellfish cleanse themselves of the toxins once the bloom is over...but depending on the species that can take more than a year.

Like a red tide,  the populations of Alexandrium can explode in the late summer as the water and air heats up, and when winds are calm and tides are low.  Warm water combined with a lack of churn create perfect conditions for billions of organisms.

But this is late January, and we are aboard the U.W. research vessel Clifford A. Barnes.  The Barnes launches equipment that reaches the bottom of Puget Sound and its various inlets and bays and pulls out  slugs of bottom sediment that ranges from a slimy mud to sand.    The top three centimeters of that bottom muck is cut off and analyzed for the presence of cysts, the "seeds" that overwinter in the muck to become fully functioning organisms when the warm weather hits.  By counting the cysts, the team thinks they may be better able to predict which bodies of water are more or less likely to host toxic toxic blooms come summer.

"So It's a human health issue. Right?" said Cheryl Greengrove, the other key investigator and oceanographer from the University of Washington in Tacoma.  "So our ideal is to be able to predict in an ideal world.  I think it's going to be tough, because there are these nooks and cranny's in Puget Sound.  But that's our long term goal."

The PS-AHAB Cyst Sampling program is surveying 99 sites from the south end of Puget Sound to Birch Bay near the Canadian Border.  This is now the second of three annual surveys of those sites.  Last year's survey found moderate to low levels in most places, zero in many,  but spikes in Quartermaster Harbor across from Tacoma's commencement bay and in Bellingham Bay.

 Will the 2012 and 2013 surveys find similar results?  Those are the comparisons that will be interesting to see once the analysis is complete.

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