Scientists say they’ve seen a surprising number of gray whale strandings this year during their migration up the west coast – 13 as of late May in Washington alone, which is more than twice the normal average.
“Just in Washington. And usually our peak continues through the end of June. So we're, you know, I think we are going to be seeing more,” said whale biologist John Calambokidis, who has studied gray whales for more than 40 years with Cascadia Research Collective in Olympia.
An ‘Unusual Mortality Event‘ (UME) of the species officially known as eastern North Pacific gray whales occurred from December 2018 to November 2023. 690 strandings were documented in that timeframe along the west coast of Northern America. Since the event was officially declared closed, the expectation has been for a rebounding population.
But this winter, at least 80 gray whales died in the warm lagoons of Baja Mexico, according to scientists there. Their surveys also show far fewer calves were born than normal.
Though not as high as the numbers from Mexico, reports of elevated numbers of strandings along the migration up the coast, as well as some unusual behavior observed, add to concerns.
NOAA Fisheries says the total strandings for all US states currently totals 47 – with 27 in California, 13 in Washington and 7 in Oregon. Last year the total was 31. In 2023, the last year of the UME, the total was 44.
“We are definitely watching carefully and continuing the counts to keep close track of what is happening," said NOAA Fisheries spokesman Michael Milstein.
While the number of strandings continues to rise, he said they still have not neared the level of the first year of the UME, when there were 122 strandings.
“It’s still a ways from that.” he said. “But there are fewer whales around too.”
More than a quarter of the population died in the UME from 2019-2023. With fewer whales around, available food should be enough. Instead, many still appear to be starving. Calambokidis says it is alarming.
“We're seeing unhealthy animals. We're seeing higher numbers of strandings. We're seeing conditions that suggest a continuation rather than a rebound, from that mortality event,” he said.
New behaviors along the coast
During a survey in late May, Cascadia’s researchers encountered three distinct large groups of gray whales, apparently attempting to feed and not migrating. One of these groups was in Grays Harbor, two others were about 20 miles north of it.
Calambokidis said this behavior appears similar to what was seen in San Francisco Bay earlier in the migration, with about 30 whales lingering and exhibiting feeding behavior. Usually, gray whales don’t stop to eat on their way to their feeding grounds in the Alaskan Arctic. This stopover behavior may be an indication of adaptability, or attempts to adapt.
A well-known group of gray whales nicknamed the Sounders are seen every year, feeding on ghost shrimp near Whidbey Island. A smaller subset in Oregon appears to be evolving as the Sounders did. Another set, the Pacific Coast Feeding Group, stops its annual migration in Washington and feeds off the coast.
But not all who try will succeed.
About half of the 27 gray whales that have stranded in California so far this year were in San Francisco Bay, where their feeding behavior may make them more vulnerable to ship strikes and other conflicts with commercial vessels.
Many of the whales that are stranding appear emaciated. The continuing deaths likely point to problems with their food supply in the Arctic, linked to climate change.
NOAA Fisheries says it will issue its latest population abundance estimate for the eastern north Pacific gray whales as soon as this week. In 2024, it was roughly 19,000.
