Scientists are baffled by what might be causing the deaths of numerous whales along the coastline of British Columbia and Alaska.
Four dead humpback whales were found off the coast of British Columbia last week alone. Since May, more than 30 whales have perished off the Western Gulf of Alaska, leading the U.S. National Oceanic and Atmospheric Administration (NOAA) to declare the situation an “Unusual Mortality Event.”
An unusual mortality event is defined as “a significant die-off of any marine mammal population” and is a definite cause for concern. What’s even more unusual is that scientists have absolutely no clue what’s causing the deaths.
The prevailing theory is that a toxic algal bloom may be responsible. Some algae produces domoic acid, a neurotoxin that the whales could be ingesting through filter feeding. But only one sample (deemed “less than ideal”) has come back from testing and was found negative for one strain of algae toxin.
Conversely, one of the whales found off the coast of Klemtu, B.C., was found with several large cuts and a gash above its tail, which suggests it died after getting entangled in ropes, though this theory has yet to be confirmed.
“We’re working closely with NOAA to analyze samples,” says Paul Cottrell, a Pacific marine mammal co-ordinator with the Department of Fisheries and Oceans Canada, who spoke with the CBC. Cottrell’s department has conducted a necropsy on two whales so far and is waiting for the results to come back to the lab.
However, it could take months, or even years, before we know what is causing all these baleen deaths. Scientists will be keeping an eye out for biotoxins in the samples.
In the meantime, the public is asked to get in touch with the Marine Mammal Incident hotline at 1-800-465-4336 to report any sightings of dead whales.
“The general public, they’re our eyes and ears out there,” Cottrell told The Vancouver Sun. “The quicker we get these calls, the better.”