Grey whales skipping Arctic migration studied off B.C. coast

Reports of grey whales washing up along B.C.’s coast this spring have raised concern among marine observers, as scientists examine whether changing ocean conditions are affecting migration patterns.

While most grey whales continue their annual journey to Arctic feeding grounds, a smaller group is doing something different, staying in the Pacific Northwest to feed.

That subgroup, known as the Pacific Coast Feeding Group, is now the focus of a growing research effort off southwest Vancouver Island.

Mark Sawyer and Ashley Hoyland, co-founders of the Whales of Clayoquot and Barkley, have been studying local grey whales for years and now work in partnership with the Marine Education and Research Society.

“We work to understand who the whales are that visit southwest Vancouver Island,” said Sawyer.

Their latest project involves drone imagery, collected with approval from Fisheries and Oceans Canada, to identify individual whales and assess body condition and feeding behaviour.

Hoyland said the focus is on the Pacific Coast Feeding Group.

“What we’re focused on doing right now is trying to record drone imagery of our local whales in this area,” said Hoyland.

The group is made up of around 230 grey whales that remain in the Pacific Northwest from Oregon to British Columbia rather than completing the full migration to the Arctic.

Researchers are still trying to understand why.

“Collaborations between different researchers across the range of these very international animals will hopefully start to be able to answer some of those quest questions in the near future,” said Hoyland.

Since 2020, the team has been documenting individual whales using drone imagery and unique markings to track identity and condition.

“2025, we recorded drone imagery of 28 different whales, and 22 of those whales that are our local grey whales,” said Sawyer.

“All these different sort of like spots and splotch pairs and scrapes and white marks of pigmentation. So they’re all very individual,” said Hoyland.

When whales surface, full-body drone images are captured. Software developed by Oregon State University is then used to estimate size and assess health.

“And that measurement creates a surface area that we can kind of get a good idea of the health of this whale just by measuring its surface area,” said Hoyland.

What may look like a stranded whale is often feeding behaviour. Grey whales forage by stirring up sediment on the seafloor to feed on shrimp-like amphipods and crab larvae.

“As it surfaces in the moment, mouth closed, tongue pumping forwards, and almost, like I would say, panning for gold,” said Sawyer

It is too early to say whether the Pacific Coast Feeding Group is faring better than migrating whales, some of which have been found dead along the coast in higher-than-usual numbers this year.

But there are early signs of improvement.

“We’re not seeing as many in that awful, that shocking condition that you’re seeing a lot of these whales migrating, migrating by,” said Sawyer.

“Moms with calves like this one last year are known to be in the worst body condition, but video evidence from Oregon this year shows her condition has dramatically improved. She’s found a reliable food source and is and has bounced back. The whales in the best condition are known to be calves. And that was backed up by the work we did last year as well,” he added.

Researchers hope continued data collection will help determine whether climate-driven changes affecting Arctic migration could eventually impact whales that remain closer to B.C.

“Is that something we’re going to start to see down here as well? Who knows? So to be able to answer questions like that have more knowledge to inform future, conservation decisions about this species. I think it’ll be it’ll be quite powerful,” said Hoyland.