BOSTON — Scientists on Friday predicted a moderate bloom of the toxic red tide in New England this summer, and they say the same water conditions that held it in check last year could suppress it again.
The naturally occurring red tide algae produces a toxin that shellfish absorb, making them potentially fatal for people to eat and forcing states to shut down affected shellfish beds until it clears.
On Friday, scientists at the federally funded Gulf of Maine toxicity project said there’s an abundance of microscopic cysts that act like seeds which the algae blooms leave on the ocean floor to restart the process annually.
But they say it’s a modest amount compared with recent years with major red tides, including 2005 and 2008.
This year’s bloom could fall between the extreme conditions in those years and the milder outbreaks in 2006 and 2007, said Woods Hole Oceanographic Institution biologist Don Anderson, principal investigator of the Gulf of Maine project’s study.
Maine shellfisherman Chad Coffin said such predictions can prove to people their shellfish is being closely monitored, and increase confidence that what reaches their plate is safe.
But he added he doesn’t bank on such forecasts, he just fishes.
“You just go [shellfishing] until it’s a problem and you hope for the best,” said Coffin, of Freeport, president of the Maine Clammers Association.
Last year’s prediction of a severe red tide outbreak turned out to be too dire. Scientists said that was partly because the algae don’t grow as well in near-surface coastal waters that were warmer, fresher and lower in nutrients than normal.
Recent observations indicate the region could see the same conditions this summer, scientists said.
The severe outbreaks do major economic damage, closing hundreds of miles of coastline to shellfishing for weeks during the peak season. The 2005 red tide’s direct and indirect costs were estimated at nearly $50 million for Massachusetts and $23 million for Maine, for instance.
The Gulf of Maine toxicity project’s prediction of a moderate red tide this year doesn’t forecast what coastal areas it might hit. Scientists are developing a computer model to predict the intensity and location of the blooms in the Gulf of Maine, but it’s not completed, and it’s impossible to know months in advance if a region will have the right weather conditions to carry the algae to shore.
“Even if there is a large bloom offshore, certain wind patterns and ocean currents in the late spring and summer are needed to transport it onshore where it can affect coastal shellfish,” said oceanographer Dennis McGillicuddy of the Woods Hole Oceanographic Institution, based in Falmouth, Mass.
Coffin said the region can better absorb outbreaks than in 2005, when only a relative handful of red tide sampling sites existed on the Maine coast, and officials made blanket shutdowns when one area showed high toxin levels. Now there are dozens of sites so officials can get more precise information and keep more clam flats open if there’s no danger.
But the money for that monitoring looks to be disappearing by next year, meaning a moderate outbreak, as predicted this year, could shut down a lot more shellfish beds, he said.
“The biggest concern of the wild Maine clammer right now is we maintain the current system,” Coffin said.