What's killing whales off B.C.-Alaska coast?

The large number of dead whales appearingalong the coast of British ColumbiaandAlaska since May is raising alarms among scientists.

Thirty dead whales have been detected in the Gulf of Alaska since May, representing a die-off more than three times the normal rate, according to the U.S. National Oceanic and Atmospheric Administration (NOAA).

• MAP: Whale strandings in the Gulf of Alaska

Another sixdead stranded whales have been reported along B.C.'s north coast over the same time period, alsoa significant increase above annual seasonal numbers.

Paul Cottrell, Pacific marine mammal co-ordinator with the Department of Fisheries and Oceans Canada, says his team is collaborating with U.S.officials to investigate the situation.

"We're working closely withNOAAto analyze samples," Cotrell said in a joint media teleconference, notingnecropsy samples had been gathered from two dead humpbacks found in B.C. waters.

The prevailing theory is that alarge toxic algae bloom offthe West Coast might be to blame. However, scientists have been unable to make a concrete connection.

Only one sample, characterized as "less than ideal," has beenanalyzedto date. It cameback negative for one strain of algae toxins.

Gathering good samples has provenchallenging.

"Alaska has an awfullot of coastline and much of it isdifficult to reach," said NOAA adviser Dr.BreeWitteveen. "We can't get to those carcasses more often than not."

As well, field scientists have encountered"predator competition" whiletrying to gathersamples, as witnessed by the news release photo showing seven large bears feeding on a fin whale carcass near Kodiak, Alaska.

So far four whales specieshave been identified in what NOAAis characterizing asan"unusual mortality event": humpback, sperm, grey and fin.

The public is asked to report any dead whale sightings, but should notapproach ortouch the animal.

In B.C. people can call the 24 hourMarine Mammal Incident hotline at1-800-465-4336.