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Gray whale numbers decline to lowest since early 1970s, according to new data
The number of Pacific gray whales decreased significantly during the most recent count to the lowest numbers since the 1970s, while the number of whale calves also hit its lowest numbers on record.
Gray whales, known for their migrations along the Oregon Coast in winter and spring, dropped to an estimated 12,900 adults and 85 calves in the latest data taken by the National Oceanic and Atmospheric Administration.
It was a sharp decline from a year ago, when the number of gray whales was estimated at 19,260 for 2023-2024, and calf numbers were estimated at 221 in 2024 and 412 in 2023.
"Our main concern and question is why the population does not appear to be demonstrating the same resilience as it has in rebounding from previous downturns," Sarah Mesnick, ecologist and science liaison with NOAA, said.
The new data reversed hope from scientists that gray whales were rebounding after they endured an 'unusual mortality event' from 2019 to 2023 and worried instead that whales may be struggling to keep up with a changing environment.
"The environment may now be changing at a pace or in ways that is testing the time-honored ability of the population to rapidly rebound while it adjusts to a new ecological regime,' said David Weller, director of the marine mammal turtle division at the NOAA Science Center and an authority on gray whales.
Researchers in Mexico reported numerous dead gray whales early in 2025 in and around coastal lagoons as well as few gray whale calves. This suggests that many female whales may not be finding enough food in the Arctic to reproduce.
So far in 2025, 47 gray whales have stranded dead on the West Coast, up from 31 in 2024 and 44 in 2023, the last year of the UME. While some of the stranded whales appeared skinny or emaciated, others did not.
'The lead scientists point out that this new estimate stands out because it reflects an extended downward trend in a population that has demonstrated short-term resilience in the past,' Mesnick said. 'The populations have previously rebounded quickly from downturns, including earlier previous UMEs, and we are going to continue to monitor the population.'
According to NOAA and under the Marine Mammal Protection Act, UME "involves a significant die-off of any marine mammal population; and demands immediate response."
Causes of UME are attributed to infectious disease, biotoxins, ecological factors, human interactions and other undetermined factors.
The gray whale population was large, at about 27,430 between 2015-2016. In the following years, a decline started from 2019-2023 to below 15,000 that was considered as unusual mortality event. It appeared that whales might by rebounding after 2023, but the latest numbers dispute that notion.
Scientists attributed the die-off to localized ecosystem changes that affected the Subarctic and Arctic feeding grounds. The changes in these areas contributed to malnutrition, reduced birth rates and increased mortality.
The migration routes, specifically the California Current ecosystem and the Arctic ecosystem, have experienced significant changes in recent decades as well, officials said.
The current research shows a connection between gray whale numbers and changes in sea ice in the Arctic, where most gray whales feed during the summer, NOAA concluded.
'They're migrating from Mexican reproductive ground, or nursery grounds, to foraging grounds in the Arctic,' Mesnick said. 'It's one of the longest migrations on the planet.'
Ecosystem changes in the Arctic feeding areas the whales depend on to put on weight and maintain fitness are likely the root cause, Weller said.
Decline in calf numbers has been linked to sea ice cover in the Bering and Chukchi seas.
In May 2024, a juvenile gray whale washed ashore on a beach in Bandon along the southern Oregon Coast. In 2023, four reported gray whales washed ashore Oregon beaches, one being a calf.
Mariah Johnston is an outdoors journalism intern at the Statesman Journal. Reach her at mjohnston@
This article originally appeared on Salem Statesman Journal: Gray whales decline to lowest numbers since 1970s
