What an upswing in gray whale health means for La Jolla and the “complicated” phenomenon of climate change.
Amid a wave of indicators that ocean warming and other climate change factors are contributing to a downturn in environmental health, there is some good news for 2026: The gray whales are having a healthy year.
“We are seeing more healthy gray whales this year than we have in … the last decade or so,” said Nicole Schriber, a graduate student at UC San Diego’s Scripps Institution of Oceanography with expertise in whales.
Image courtesy of Nicole Schriber
Gray whale health is measured in population counts and an LA-based gray whale census as the whales migrate annually about 10,000 miles roundtrip from the icy waters of the Arctic past San Diego to the warm lagoons of Baja California, Mexico, where they breed and give birth.
The whales’ health is also measured in terms of body condition; data is collected via drone imagery.
Image by Jenna Hoffman
“There’s definitely an upswing” in gray whale health, Schriber said, noting “last year was really, really bad,” with much malnutrition and emaciation recorded and whales “washing up dead, … so incredibly skinny they couldn’t sustain themselves.”
The gray whales are healthier now, she said, with a “lot more babies this year than last year, which is obviously great news for the population.”
Image courtesy of Nicole Schriber
The improvement led to “one of the best gray whale seasons” for watching the migration, Schriber said, adding that “healthy whales have energy to expend, so we can see them more often, doing cool behaviors [and] lots of babies going by the coast, which is always really special.”
The “boom and bust” cycle of gray whale health
The comeback in whale health after the recent die-off, which Schriber said is called an “unusual mortality event,” might simply be a numbers game: With so many whales gone, there are fewer to compete for food sources, she said.
Gray whales feed in the Arctic region, in the Bering and Chukchi seas between Alaska and Russia, Schriber said. “It’s a really good area with shallow, productive waters.”
Gray whales are the only living species of baleen whale that eat primarily ocean floor-dwelling amphipods, small, shrimp-like crustaceans that live in the sediment and mud and have a much higher lipid content than other crustaceans in the area.
Image courtesy of Nicole Schriber
“The problem is that these amphipods really rely ultimately on sea ice,” Schriber said. When sea ice collects and sits undisturbed for a time, a lot of algae forms on the bottom of the ice, dies and “kind of rains down to the sea floor,” providing the amphipods with food.
The overall decline in sea ice leads to a decline in algae, then a decline in amphipods, and then an overall decline in gray whale numbers, Schriber said.
But the decline isn’t quite linear, she emphasized. “There’s a little bit of a trade-off.”
With too little sea ice, amphipods can’t survive; but if there’s too much sea ice, the gray whales can’t access their feeding areas either.
There needs to be “a perfect balance between too much and too little sea ice,” she said, “and obviously the way things are going, the main issue, especially in the future, is primarily going to be the too little sea ice.”
And now, those rising numbers of healthy whales will create more competition, Schriber said. Eventually, there may not be enough food for all.
When the whales reach a certain population size, “they’re at ‘carrying capacity,’ where they can no longer sustain themselves with the amount of resources that there are, and that will cause a drop in those numbers again,” she said.
And as we lose sea ice throughout years and decades, that carrying capacity, or the number of whales that the ecosystem can support, will also decline.
Therefore, this year’s health boom won’t be a long-term trend, Schriber predicted.
Noticing the cycle is “a really good lesson in how complicated” climate change is, she said.
“Obviously warming oceans is … blanketly bad for everything linearly, but then you see these weird fluctuations. … You really have to dig deeper and think about the different reasons,” she said.
Gray whale carcass off the coast of Alaska/Image courtesy of Nicole Schriber
“We’ve got to act now,” she added. “If things get too out of hand, then we’re going to lose the whales completely. We still have this window of time where we can actually make a difference in the Arctic habitat.”
And that difference isn’t just in trying to save the gray whales; the warming oceans affect the amphipods, which impacts “these extremely big, charismatic animals that we love,” she said.
“It’s really important to protect the little stuff if you want to save the big stuff.”
