U.S. warns of 'dangerous' shellfish south of B.C. border
By Lori Culbert, Vancouver SunJuly 6, 2010
U.S. officials have detected "extremely dangerous" toxin levels in shellfish at two coastal areas near the B.C. border.
Marine biotoxins that cause paralytic shellfish poisoning (PSP), also known as "red tide," have been found at "potentially lethal levels" in shellfish samples recently collected from Point Roberts, just south of Tsawwassen, and Drayton Harbor, in Blaine, Wash.
"The public is warned that consumption of molluscan shellfish with such high toxin levels can result in severe illness or death," said a statement issued Thursday by Tom Kunesh, Whatcom County's Environmental Health Supervisor.
"These levels are higher than what we usually see," Kunesh added in an interview Friday.
Molluscan shellfish includes clams, mussels, oysters and scallops, and the biotoxins cannot be destroyed by cooking or freezing.
Kunesh said shellfish harvesting has been banned in Whatcom County since June 9 -- a typical occurrence in the summer months -- but the more
severe warning was issued after testing detected even higher biotoxin levels.
He said every summer produces different biotoxin levels, and noted there was no immediate explanation for this year's spike -- except for the possibility it was caused by a recent rise in temperatures following a prolonged heavy rain.
In Canada, the Department of Fisheries and Oceans (DFO) announced Friday a ban on shellfish harvesting in parts of the Southern Gulf Islands and the southern tip of Vancouver Island as a "precaution ... due to rising PSP levels in neighbouring waters in the U.S.A."
Most shellfish harvesting has been fully or partly banned along B.C.'s coast for several weeks; a DFO bulletin issued late Friday warned red tide levels are "high" due to "unacceptable or rising" toxin levels in some of the
closed sections along the north coast, the west coast of Vancouver Island, and the Strait of Georgia.
"The public is strongly urged to comply with fishing regulations and not harvest any shellfish from these areas," the July 2 DFO bulletin said.
"Additionally, Washington state's biotoxin monitoring program has detected extremely toxic levels in areas adjacent to Canadian waters."
However, a DFO scientist indicated Friday that biotoxin levels in B.C. are not as severe as those seen in Washington state, and that it is not unusual for the levels to fluctuate throughout the summer, department representative Tim Robbins said in an interview.
It is still safe to eat shellfish that has been legally harvested and has passed health inspections, the DFO bulletin added.
Red tide or PSP is caused by naturally
occurring algae or plankton, which intensifies when temperatures rise.
The symptoms associated with eating toxic shellfish can appear within minutes or hours, and typically begin with tingling in the lips and tongue, which can move to the hands and feet. Severe cases can result in difficulty breathing and, potentially, death.
The Canadian Food Inspection Agency regularly tests hundreds of sites in B.C., Atlantic Canada and Quebec for red tide toxins in shellfish. The agency notifies the DFO when levels are "unacceptable," and then the affected area is closed to shellfish harvesting and patrolled by fishery officers, the CFIA website says.
Meanwhile, the BC Centre for Disease Control issued a bulletin this week reminding residents that, as summer temperatures increase, eating raw or undercooked shellfish -- regardless of whether it contains red tide toxins -- can cause illness.
Because a naturally occurring bacterium found in shellfish is present in higher concentrations in the summer, the centre advises residents to only buy federally inspected shellfish, to refrigerate it immediately after purchase and to cook it well.
"Consuming raw or undercooked shellfish can cause severe diarrhea and vomiting that can last up to a week," Dr. Eleni Galanis, physician epidemiologist with BC Centre for Disease Control, said in the statement.
lculbert@vancouversun.com© Copyright (c) The Vancouver Sun
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