Saturday, 2:15 PM
Red tide outbreak forces ban on North Shore shellfishing
By David Abel, Globe Staff
Red tide has spread from central Maine to Gloucester, making it unsafe to harvest soft shell clams or mussels from those coastal waters, state officials said.
|(Paul Cunningham/The Times Record) A clam digger trudged across mudflats in Freeport, Maine, where red tide has limited the shellfish harvest.|
The single-celled algae carries toxins that concentrate over time in shellfish, making them poisonous, even lethal. Red tide often occurs in late spring and summer, when the algae grow rapidly. Crabs, lobsters, fish, and shrimp are not affected.
“It’s a little earlier than usual, but it’s not abnormal to have red tide now,” said Michael Hickey, chief biologist for the state Division of Marine Fisheries. “We are always watchful of this from the beginning of May.”
The state has sampling stations that test shellfish every two days. He said a no-harvesting order along the North Shore took effect on Thursday for mussels, carnivorous marine snails, and soft-shell clams.
Hickey added there’s no risk for residents who eat clams or mussels already on the market. The state suspends harvesting when officials find 80 micrograms of the toxin for 100 grams of shellfish meat. It takes between 250 and 300 micrograms to make people sick.
He said some oceanographic models show this year’s bloom could approach the damage that occurred in 2005.
“I’m not in a position to make predictions, but we’re always worried,” Hickey said. “We have to be ready for that.”
The 2005 outbreak, which also began in the middle of May, extended from northern Maine to Nantucket. It halted business for nearly 2,000 clammers, oyster farmers, and mussel harvesters for much of the summer. They lost tens of millions of dollars, and cell counts were 40 to 100 times higher than normal.
The state has been monitoring red tide since 1972, when there was also a large outbreak.
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