The Bangor Daily News
Tuesday, June 30, 1998
Red tide closes part of coast to Clamming
Rains may aggravate condition
By Mary Anne Clancy
Of the NEWS Staff
-- MACHIAS -
For the first time in several years, the discovery of a shellfish
toxin commonly referred to as redtide has shut down part of the
Washington County coastline to clammers and mussel fishermen.
The closed area stretches east from Moose Cove in Trescott up
to Calais, according to a June 27 announcement by the Maine Department
of Marine Resources. Not included in the precautionary action
are flats from Gove Point in Lubec to Birch Point in Perry. The
western part of Cobscook Bay, including South Bay, Straight Bay
and Whiting Bay, remain open.
John Hurst, DMR's director of toxins and monitoring, said the
closure was expected following a similar closure in Canada the
week before last.
Hurst said he did not know when the flats would be reopened.
During the summer, DMR takes weekly samples of clams and mussels
the entire length of the coast, Hurst said, and reopening will
depend on the results.
With the exception of Casco Bay, which was closed for only two
weeks last year, there were no other closings in Maine in 1997.
Hurst said there were hardly any red tide closings in Maine the
previous year.
He said the longer he looks at red tide, the less he knows, but
Hurst suspects that the last two years of droughtlike conditions
are why Maine did not have much of a problem with red tide. An
infusion of fresh water from rain or runoff means more nutrients,
which appears to aggravate the condition, he added.
Red tide is the common name for paralytic shellfish toxin, or
PST. It stresses clams but does not kill them. Eating the clams
or mussels can make people extremely ill and, in some cases, kill
them, Hurst said.
No deaths have been reported in Maine, but there have been outbreaks
of illness in years past, he said. Several people were hospitalized
in Halifax, Nova Scotia, after they ate mussels contaminated by
the toxin last week, he said.
PST is weather-related and is caused by a proliferation of a type
of algae called Alexandrium tanarense, according to Hurst.
"Since it's a plant, it has to have sunlight," Hurst
said. "In Maine, we start worrying April 1 and stop in October."
Hurst said the algae divides as a means of reproducing in the
spring. Seed-like cysts are formed on the algae, and the cysts
drop to the ocean floor and sprout. When conditions are right,
the sprouts rise to the top. If there isn't enough competition
from other types of algae or sea organisms, Alexandrium tanarese
predominates.
Winds can blow the toxic algae into shore where clams feed on
it, he said. If there are offshore winds, the algae can't come
in.
"Last summer and the summer before, we had hardly any,"
Hurst said.
Hurst said he does not believe PST is caused by pollution because
the algae originates offshore.
The state's involvement in monitoring for red tide began 40 years
ago when the national Public Health Service directed the state
to test clams and mussels in the waters bordering Canada. PST
had shown up in Canada, and the boundary line between the two
countries doesn't mean anything to the shellfish, Hurst said.
Hurst believes PST has been around for hundreds of years. There are parts of Washington County where, traditionally, people won't eat clams in the summer, he said. Hurst believes the tradition stems from long-ago experiences with the upset stomach and tingling lips that are indicative of PST.