Scientists rule out red tide in mystery kill of 17 whales

BY ALISON AULD
Canadian Press
August 16/03

   HALIFAX - Scientists were scratching their heads Thursday after discovering that several whales found in an area that straddles American and Canadian waters did not die from exposure to a toxic algae as was previously thought.
   Results showed that four of 17 dead whales had no traces of red tide in their livers, urine, feces or stomachs, confounding researchers who assumed the lethal toxin was behind the large die-off.
   "These findings have made this an even bigger puzzle than it was a week ago - we're back to Square l," Jerry Conway, marine mammal adviser with the Department of Fisheries and Oceans, said in Halifax.
   "There is no indication of any red tide in any of the animals' organs.
   "The mystery continues".
   Scientists in both countries have been conducting various tests on samples taken from some of the 17 whales found in a shallow area off southwestern Nova Scotia.
   They 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.
   Preliminary findings last week showed the water and a certain fish species the whales ate in the region near Georges Bank contained no traces of the algae.
   Marine biologists were still awaiting results from other tests that could yield some insight into one of the largest whale kills 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.
   The difficulty in solving the mystery is trying to determine where the whales were before they died.
   It's possible that they were exposed to a different contaminant in another area and then succumbed to the toxin in the region where they were found.
   Officials with the U.S. federal fisheries service were also awaiting test results on the whales' blubber, which could show signs of toxins.
   Teri Frady, spokeswoman for the U.S. National Oceanic and Atmospheric Administration Fisheries in the Northeast, said those findings were not yet available.
   Other agencies were tracking the locations of algae blooms along the northeastern U.S. coast to see if they could be linked to the deaths.
   Both Canadian and American fisheries officials were using planes and boats to search the area for another fresh carcass, which they would examine for more clues as to the cause of death.
   But they've been unable to find any of the other whales, due partially to thick fog in the area.
   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 Georges 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.
   The whale carcasses showed no sign of trauma, 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.