By Angeljean Chiaramida
Staff writer
May 10, 2008 03:50 am SEABROOK — Red Tide is again sweeping through the region's coastal waters, forcing state officials to ban harvesting of mussels, clams and oysters from New Hampshire coastal waters and Hampton/Seabrook Harbor. People are warned that eating contaminated shellfish can cause illness or death. The ban is in response to high levels of Paralytic Shellfish Poisoning, known as the Red Tide, found in blue mussels collected from the Isles of Shoals and the harbor. Closures have not come to the North Shore of Massachusetts, but after tonight's nor'easter drops its share of rain, the risk is there, said Dan Whitaker, senior biologist for the Massachusetts Division of Marine Fisheries. "We've luckily dodged a bullet so far," Whitaker said. We went out and sampled Thursday, and those samples came back negative." New Hampshire Shellfish Manager Chris Nash, of the state Department of Environmental Services, said it's too soon to know how long the ban will last or how severe it will be. However, toxicity in Hampton/Seabrook is appearing earlier than in previous years. Officials at the DES made the decision to ban shellfish harvesting to protect public health. "Red tide toxicity levels are increasing right now, in both offshore and near-shore waters," Nash said. "It is too soon to know how severe this algae bloom will be, or how long it might last." Nash noted weekly sampling will continue from now until October. Officials had predicted this year would be a particularly bad year for red tide, due to the unusually large size of a red tide-causing algae bloom in the Gulf of Maine. Blue mussels collected from Hampton/Seabrook last week showed low toxin levels, but samples collected this week exhibited toxin levels above the mandatory closure threshold of 80 micrograms of toxin per 100 grams of shellfish tissue. Blue mussels from Star Island, Isles of Shoals, are also exhibiting high toxicity values. Last night's storm and the New Hampshire closures will have Massachusetts officials on alert for North Shore clam flats. "With the rain directly washing off land and feeding these things, then the wind keeping them on shore with a medium of fresh water and humus (decomposed organic material), it's perfect conditions for growth of these (red tide) cells," Whitaker said. But he added it takes time for the levels to rise in the shellfish. The nature of red tide blooms varies from year to year, Nash said. A red tide bloom in 2005 was the most widespread toxic event on record for New Hampshire waters. The past two years have had less-severe events, characterized by high toxicity in the offshore Atlantic waters and lower levels of toxin along the beaches. Red tide is a condition in which filter-feeding molluscan shellfish, such as clams, oysters and mussels, accumulate a potent neurotoxin produced by a naturally occurring marine algae. Ingesting the toxin is potentially fatal to humans, and cooking does not make contaminated shellfish safe for consumption.
The Associated Press contributed to this report.
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