Tests show no sign of red tide in area where whales died

BY ALISON AULD
Canadian Press
Aug. 09/03

    HALIFAX - Scientists are reworking a theory that 17 whales died from eating toxic algae off southwestern Nova Scotia, after early tests showed no signs of the lethal red tide in the immediate area.
   Preliminary findings show the water and a certain fish species that the whales ate in the region near George's Bank had no traces of the algae.
    American and Canadian scientists had suspected the fin, pilot and humpback whales became exposed to the toxin through the water or the tonnes of krill they eat every day.
   Still, the negative findings have raised the possibility that the whales could have become contaminated in another region and then died in the shallow area that straddles Canadian and U.S. waters.
   "So the question is still there and we're continuing our investigation to determine the cause," Jerry Conway, marine mammal adviser with the Department of Fisheries and Oceans, said Friday.
   "There is a probability that it is a toxic issue, but not in the area where we found the whales."
   Marine biologists are still awaiting results from a battery of other tests that could yield some insight into the one of the largest whale die-offs in recent years.
   The last time so many whales died this close together was in 1987, when red tide killed 14 off the New England coast.
   A key piece of information is where the whales were before they died.
   Officials with the U.S. federal fisheries service were conducting tests on four of the animals' digestive tracts to find out what they ate and if it was toxic.
   Canadian marine mammal experts were also awaiting results on the whales' blubber, which could show signs of toxins.
   "We might be able to get from that whether there was a contaminant, which could help figure out where they were," Teri Frady, spokeswoman for the U.S. National Oceanic and Atmospheric Administration Fisheries in the Northeast, said from Woods Hole, Mass.
   Other agencies are tracking the locations of algae blooms along the northeastern U.S. coast to see if they could be linked to the deaths.
   A U.S. fishery patrol boat discovered four dead whales - three humpbacks and one fin - at the end of July on the northeastern tip of George's Bank, an underwater plateau that extends from Nova Scotia to Cape Cod.
   They found several more humpbacks and a pilot whale over the next few days before adding about a dozen more to the toll.
   Mr. Conway said a patrol vessel is now searching for a dead humpback that can be used for a necropsy, or animal autopsy.
   They haven't yet recovered an intact animal and are hoping a fuller examination will help pinpoint the cause.
   The whale carcasses showed no sign of trauma, Ms. Frady said, indicating they likely weren't hit by passing ships or entangled in fishing gear.
   Both are common causes of death for most whale species.
   Red tide is a naturally occurring part of the food chain. Small quantities will not typically affect humans, but large amounts can cause nausea, fever, paralysis and even death.
    The toxin is more dangerous to whales because they eat whole fish by the tonne.

©WebWise Inc.