This story was originally published on LincolnChronicle.org and is used with permission.
An alarming new federal report released Wednesday indicates that the number of gray whales in the Pacific Ocean has dropped to the lowest number in decades and that the decline may be only getting worse.
The eastern North Pacific population of gray whales, going back to the 1970s, has experienced period dips. But warming ocean conditions, along with plummeting birth rates, mean the whales are now facing their biggest challenges in memory, National Oceanic and Atmospheric Administration researchers say.
“We’re definitely concerned,” Aimee Lang, NOAA’s lead gray whale researcher told the Lincoln Chronicle on Wednesday. “Those declines in the past were always followed by significant rebounds and we’re just not seeing that this time.”
Following what is formally labeled as an “unusual mortality event” that ended two years ago, initial population estimates of gray whales last year suggested that overall numbers had begun to climb.
However, the migration count from this winter shocked scientists by dropping their numbers to an estimated 13,000 whales, NOAA said, the lowest in at least 50 years. That compares with the estimated 27,000 gray whales that were counted a decade ago.
The number of gray whale calves that migrated past central California this winter, according to the report, provided even worse news. Only about 85 calves were counted as they made their way from Baja Mexico lagoons to feeding grounds in the Arctic, the lowest number since records began in 1994. By comparison, nearly 2,000 calves were reported in 2004.
“Low calf numbers since 2019 indicate that reproduction has remained too low for the population to rebound,” according to the report released Wednesday.
“The estimates are based on models that combine visual sightings from NOAA Fisheries research posts in central California with assumptions about how the whales migrate,” the report said. “The assumptions create some margin for error, but the models indicate that in 2025 the population is most likely between 11,700 and 14,500. They indicate the number of calves produced was between 56 and 294.”
“It’s very grim,” said Alisa Schulman-Janiger, who leads an effort just north of Los Angeles to count Pacific gray whales on both legs of their 10,000-mile migration from Mexico to the Bering Sea and back. “It really confirms my worst fears. I thought it would be very bad and it is very bad.”
Schulman-Janiger told the Chronicle three months ago, when her volunteer-led count was underway, that the numbers of adult whales and calves appeared to be distressingly low. The new report only confirms that, she said.
“I’d heard rumors just a few months ago that the population could number as high as 15,000,” she said. “We now know it’s not even close to that, which is really scary.”
No moss
The apparent reasons for the dramatic population decline are complicated and interrelated, researchers say. But the biggest problems appear to be rooted in the Arctic, where diminishing sea ice is having a profound effect on the food production that whales rely on.
Warming ocean temperatures there are causing sea ice to melt faster and farther than usual. That melting is having a big impact on pregnant mothers, who are the first to arrive at their traditional summer feeding grounds.
In prior years, longer-lasting sea ice gives a type of algae on the underside of the ice time to fully mature, Josh Stewart, an ecologist in Oregon State University’s Marine Mammal Institute in Newport, told the Chronicle in a recent interview.
Once fully developed, the algae die and sink to the sea floor where, under normal conditions, their numbers are sufficient to essentially fertilize the sea floor, he said. That, in turn, triggers the growth of the shrimp-like creatures that gray whales prefer.
“Now, less dying algae is making its way to the sea floor,” Stewart said. “Instead, it’s getting mixed into the water column, causing a huge shift in the amount of available biomass.”
Stewart said Wednesday he was among those who were briefly optimistic that the whale population might be on its way to recovering this year. The new report, however, dashes those rosy projections, he said.
“The biggest signs that this is really different from previous years is how long the reproductive output has remained depressed,” Stewart said. “The most recent year, I don’t know anyone who expected it to go lower, but we learn now that it has dropped even more. It’s definitely a continuation of a downward trend.”
Changing behavior
Whale behavior may be changing as some of the planet’s largest mammals cope with a declining food supply, Stewart and others said.
In “normal” years, gray whales stock up on food in the Arctic from May to November, building fat for their long southward migration. Then they head to the lagoons off Mexico, where calves are born in the warm, shallow waters.
Researchers this year sounded alarm bells as numerous dead gray whales were reported in and around the coastal lagoons.
“They also reported few gray whale calves,” according to the new report, “suggesting that many females whales may not be finding enough food in the Arctic to reproduce.”
In attempting to supplement that dwindling supply, significant numbers of whales popped up in San Francisco Bay this year on their northward swim, Stewart and others said.
“That indicates to me that they are in poor condition and in need of more food,” he said. “This is their longest period between fasting and reaching the Arctic, and their showing up in the bay suggests they are looking for stop over points to add fuel to the tank.”
That novel need for a new food supply, however, poses additional hazards for gray whales, especially in a heavily trafficked area such as San Francisco Bay, where boat strikes — already a huge threat to gray whales — are likely to occur even more often.
Low nutrition, meanwhile, increases the likelihood that whales will end up stranded somewhere along their journey.
“So far this year, 47 gray whales have stranded dead on the U.S. West Coast, up from 31 last year and 44 in 2023, the last year of the (unusual mortality event),” according to Wednesday’s report. A fair number of those stranded whales appeared skinny or emaciated, it added.
“All of this is brutal to see,” Stewart said. “For those of us who had hoped for a turnaround, this is all pretty disheartening.”
- Dana Tims is an Oregon freelance writer who contributes regularly to Lincoln Chronicle, formerly YachatsNews and can be reached at DanaTims24@gmail.com