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Gulf of Maine whale deaths raising fears of toxic algae
2nd August 2003
By JOSIE HUANG,
Portland Press Herald
More than 15 years after dead whales washed ashore at Cape Cod, history may be repeating itself.
Scientists investigating a cluster of whale carcasses in the Gulf of Maine say a near-invisible, toxic algae blamed for at least 14 whale deaths in 1987 may have struck again.
Blubber, skin, waste products and stomach fluid collected this week from six dead whales floating hundreds of miles off the Maine coast will help determine whether the culprit is an algal bloom, often called red tide because of its appearance when heavily concentrated.
Marine experts say the naturally occurring neurotoxin in the algae may have been passed to the whales by the small fish they eat. The toxin could have incapacitated the whales and kept them from breathing or feeding properly, said Donald Anderson, a principal investigator and senior biologist at Woods Hole (Mass.) Oceanographic Institution.
A team of researchers planned to revisit the carcasses on Monday to take water samples, knowing full well the difficult task they face searching for clues in a dynamic water system.
But, Anderson said, "If we can find the toxin in the whale tissue and find that there are still a lot of toxic cells in there, then we'll have the smoking gun, or at least the best we're going to get."
Authorities say at least 10 whales have been found dead in July near Georges Bank, an underwater plateau that extends from Cape Cod northeast to Nova Scotia and separates the Gulf of Maine from the Atlantic Ocean. It is about 200 miles southeast of Portland.
Casualties include one fin whale, one pilot whale and between six and 12 humpback whales, according to the National Oceanic and Atmospheric Administration Fisheries in the Northeast. Dead whales are also cropping up in Canadian waters. Canadian news reports put the number at more than a dozen.
The whales had been dead for between a week and a month when they were found, said Teri Frady, spokeswoman for the federal agency, which is charged with large-whale protection.
If the test results, expected by next week, are inconclusive, experts may try to pull a more recently deceased animal to shore for more complete testing, Frady said.
Toxic algae has emerged as a probable cause as other suspected causes grow less likely. Anderson said veterinarians did not notice viral symptoms in the whales, and NOAA Fisheries said there were no obvious signs of trauma.
Large numbers of whale deaths are rare, and some scientists say an unusual set of events must have occurred, like the ones believed to have led to the 1987 whale deaths.
That year, mackerel had migrated south from the Gulf of St. Lawrence, where they likely ate toxic zooplankton, just as the whales were preparing to migrate to the Caribbean and needed to consume a lot of food to generate energy.
Because the sand lance typically eaten by the whales was in short supply that year, the animals switched to eating the toxic mackerel.
"The fish kept eating zooplankton without being killed and the poor whales didn't stop eating the fish until they were dead," said oceanographer David Townsend.
Townsend, director of the School of Marine Sciences at the University of Maine, said it is unlikely that the whales got sick near Georges Bank. He said fish likely consumed the algae in two areas in the Gulf of Maine that are prone to algal blooms - the mouth of the Bay of Fundy and a patch located 50 miles south of Penobscot Bay.
"My guess is that the fish that had been eating the toxic zooplankton were followed to the point where the whales ate them and (then) moved onto Georges Bank," Townsend said.
Scientists say there is little chance that the toxic algae will find its way to the coast of Maine because of the currents - good news for the shellfish industry.
Algal blooms closer to the coast already force the state to regularly close shellfish beds on a temporary basis. In humans, toxins can cause dizziness, nausea, fever, paralysis and even death.
John Hurst, who directs bio-toxin monitoring in shellfish for the Maine Department of Marine Resources, said the state's monitoring system "will keep everyone from getting sick."
"If we find that shellfish are getting toxic, there'll be closings," he said. "The Maine patrol people will see to it that you won't harvest, and dealers don't want it anyway because they don't want to be sued by somebody."
Anderson agreed, praising Maine's shellfish monitoring system as "one of the best in the world."
Material from The Associated Press was used in this report.
Staff Writer Josie Huang can be contacted at 791-6364 or at:
jhuang@pressherald.com
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