Red Tide Creeps Along New England's Coast; Seen as Area's Worst Since 1993

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A massive red tide has prompted state environmental officials to shut down shellfish beds from Central Maine to Cape Cod, drastically limiting local supplies of clams, oysters, sea scallops and mussels.

A massive red tide has prompted state environmental officials to shut down shellfish beds from Central Maine to Cape Cod, drastically limiting local supplies of clams, oysters, sea scallops and mussels.


Red tides occur when a combination of certain oceanographic conditions creates explosive algae growth that takes the form of large, visible "blooms" that can appear rusty in color and contain algae species that produce neurotoxins as they grow. Shellfish feed on the algae, concentrating their toxin in their flesh.


People who eat shellfish exposed to high levels of the toxin can develop paralytic shellfish poisoning, or PSP. Lobsters, shrimp, crabs, and fish are not affected, and shellfish currently in stores is safe, officials said.


J. Michael Hickey, the state's chief shellfish biologist, said this red tide is New England's worst since 1993, and that it is expected to last from two to four weeks, depending on weather, currents, and other factors.


"Some years you have little blooms that don't amount to a whole lot," he said. "This year, it looks like we're going to have a big one."


Hickey said the bloom would probably drive up the price of shellfish and hurt local shellfishermen. Duxbury oyster farmer George Shamma said he feared a big loss.


"If I lose what I have ready to harvest, I'd lose up to $400,000," Shamma told the Patriot Ledger.


Hickey said Massachusetts shellfish officials have been tracking the bloom since it began spreading in the Gulf of Maine several weeks ago. Researchers at Woods Hole Oceanographic Institute studying PSP have been following the bloom by boat, sending regular reports almost daily.


As winds and currents pushed the tide toward shore, Maine began closing shellfish beds two weeks ago. New Hampshire closed beds on the Isles of Shoals a week ago and shut down its coastline midweek, Hickey said.


Massachusetts, which tests shellfish weekly, has stepped up its testing to twice a week, Hickey said. By the end of the week, the shellfish were reaching quarantine levels of toxin, Hickey said, so the state closed all shellfish beds from the New Hampshire border to Scorton Creek in Sandwich, which is just east of the Cape Cod Canal.


Boston Harbor, which is rarely affected by red tides, remained open to a few commercial fishermen with special licenses.


Red tides rarely affect the warmer waters south of Cape Cod, Hickey said.


Nobody in the United States has died of PSP since red tide first arrived in US waters in 1972, Dave Whittaker, a senior marine biologist with the State Division of Marine Fisheries, told the Eagle-Tribune of Lawrence.


Material from the Associated Press was used in this report.


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Source: Knight Ridder/Tribune Business News