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.