Winds may decide red tide outbreak

By Beth Daley, Globe Staff

New England's seabed has all the ingredients for a severe red tide outbreak this year – but how much it impacts the seafood industry literally depends on which way the wind blows.

Abundant seed beds of the toxic algae and heavy winter precipitation have set the stage for a bloom of the ilk that caused shellfish beds to close from the Bay of Fundy to Martha’s Vineyard in 2005. Toxins in the algae can accumulate in clams, mussels and other shellfish and cause paralytic shellfish poisoning in humans who eat them.

Cysts of the organism that cause red tide stand out in yellow and bright green from organic matter and sediments collected from the Gulf of Maine. (Photo by Kerry Norton, Woods Hole Oceanographic Institution)

Woods Hole Oceanographic Institution scientists who are trying to develop a red tide prediction system for the seafood industry said strong spring northeast winds could drive the algae toward Southern New England and the region’s rich shellfish beds. But if southwesterly winds dominate, the algae would likely stay offshore and not impact many shellfish beds.

“Will the conditions this spring lead to an extensive bloom along the New England coast? The wind patterns of the next few weeks will determine that,’’ said Dennis McGillicuddy, a biological oceanographer with Woods Hole.

While his team is hesitant to make any official forecast until the model is more fully tested, they did find that algae seeds – or cysts – off mid-coast Maine were 30 percent higher than what was seen in the sediments just before the devastating 2005 bloom.

Their work also shows that the region’s above-average winter rain and snowfall poured fresh water and nutrients into coastal waters – perfect conditions for the dense mats of the reddish-tinged algae to flourish.

McGillicuddy and more than dozen students, technicians and biologists are leaving today for the first of four expeditions to examine this year’s bloom and study the cause of several blooms in the rich fishing grounds of Georges Bank.