A grey whale found in Boundary Bay in the Vancouver region is the second dead whale in B.C. so far this year, a period during which mortality off the province’s shores has dropped.Brad Persson/The Globe and Mail
Brad Persson noticed an unusual shape in the water near his home in Surrey, B.C., last weekend. Thinking it might be a log or overturned boat, he kayaked over to investigate.
“Sure enough, it was a whale,” he said.
The body of the massive grey whale had washed onto sandbars of shallow Boundary Bay in the Metro Vancouver city. Mr. Persson noted the absence of decay and smell, leading him to believe it was recently deceased.
He promptly contacted Fisheries and Oceans Canada, sending them some photos for further assessment.
On Wednesday, Fisheries officials managed to get the whale carcass onto a hovercraft and ferried it to a secure location where a necropsy will be performed.
The find could be invaluable for fisheries scientists.
Paul Cottrell, a marine mammal co-ordinator with the federal Fisheries Department, said it’s the second dead whale in British Columbia so far this year, a period during which mortality off the province’s shores has dropped. Mr. Cottrell and his colleagues are hoping this latest specimen will help them figure out why.
The DFO will collaborate with Stephen Raverty, a veterinary pathologist with B.C.’s Animal Health Centre to do the necropsy.
Mr. Cottrell said there were 11 whale deaths in 2019 and five each in 2020, 2021 and 2022. There were six in 2023.
“We lost around 30 per cent of the grey whale population over that that time, so that was a real concern,” he said.
Dr. Raverty and Mr. Cottrell were among the authors of a study published earlier this year in the journal PLOS One that examined a spike in grey whale deaths along the Pacific coast of North America starting in 2019.
The study found that between December, 2018, and December, 2021, there were 503 strandings, including 21 in British Columbia. Necropsies were done on 61 of them and scientists were able to figure out what contributed to the deaths of 33. Starvation and blunt-force trauma, likely from being struck by a vessel, were the most common causes of death. Nineteen of the 61 whales examined showed signs of interaction with orcas, including three that were likely killed by the encounter.
The spate of deaths was officially declared an unusual mortality event by the U.S. National Marine Fisheries Service but the mortality rate appears to be abating.
Mr. Cottrell said there is no obvious cause of death with the latest specimen, but that the creature was badly emaciated and infested with cyamids, which are whale lice.
Dr. Raverty said that from 2017 to 2018, the estimated total population of grey whales in the western Pacific was around 28,000. However, over the following five years, this number halved, with population estimates dropping to 14,000 by 2022-2023.
He said the decline is linked to a reduction in feeding areas in the Arctic. Climate change-induced ice retreat forces these animals to travel longer distances for food and meanwhile, the nutrient quality of available prey has also decreased.
On top of that, he added, vessel strikes pose a significant threat, especially in regions with frequent vessel interactions such as Los Angeles, San Francisco, Seattle and the west coast of Vancouver Island.
Dr. Raverty said it remains unknown why the population started to recover. However, he pointed out that similar cycles occurred in the past including in the late 1980s and in 1999-2000.
“There’s a historic precedent where there have been repeating cycles about every eight to six years, where there’s been an abrupt significant decline in the population levels,” he said.
“This is something that we still don’t really understand. But it likely is related to primary productivity within the environment.”
Mr. Cottrell commended Mr. Persson’s decision to call the British Columbia Marine Mammal Response Network to report the incident.
“When you do these necropsies, the fresher the animal, the more information you get.”