The deaths of more than two dozen whales in B.C. and Alaskan waters since May may be linked to climate change in the Pacific Ocean, a University of British Columbia professor says.
Large humpbacks and fin whales have been washing up on shores in the Pacific Northwest for months, but the cause in most cases has been undetermined.
Dr. Andrew Trites, director of the UBC Marine Mammal Research Unit, is trying to unravel the mystery behind the die-offs.
“We can rule a few things out by having inspected their bodies to rule out things such as starvation, any signs of disease, any signs of having been hit by ships or caught by fishing gear,” Trites said. “We have to begin, in essence, doing ecological detective work.”
That sleuthing led Trites to a massive warm water patch in the Pacific commonly referred to as the “blob” that has been blamed for causing toxic algal blooms.
Domoic acid, a neurotoxin found in the algal blooms, is likely passed on to krill, a common food of both species of whale, Trites said.
If ingested in large amounts by birds or mammals, it can cause brain damage, seizures – and death.
“I think the most likely explanation for the deaths of these whales is that they were out at a big smorgasbord, a big party, and some of them got food poisoning,” he said. “They ate too much, and it caused their deaths.”
He said the deaths are a “wake-up call” that climate change is affecting not only those on land, but ocean life as well.
“The fact that three times more whales have died this year than we’ve seen in past years is a sign that something major has happened.”
Scientists haven’t been able to confirm that the neurotoxin is killing whales because the carcasses recovered so far haven’t been fresh enough to detect its presence.
“I think it’s a mystery that will never be 100 per cent solved,” he said.
But researchers at Victoria’s Ocean Networks Canada support Trites’ hypothesis – saying it holds water.
“A whale’s at the top of the food chain, and so in fact they are an accumulator of toxins,” said Richard Dewey, ONC’s associate director for science. “We would expect the larger species to have the highest concentration of these toxins.”
The Department of Fisheries and Oceans isn’t as quick to draw conclusions, telling CTV News in an email scientists are still testing samples from several dead humpback whales.
The DFO said any cause of death given so far is just speculation.
Since May, 11 fin whales and 14 humpbacks have been found dead in Alaska while four humpback whales have been found dead in B.C., according to Trites.
With a report from CTV Vancouver Island’s Scott Cunningham
