Concerns about the survival of the migratory gray whale (Eschrichtius robustus) are growing. Sightings of malnourished or “skinny” animals, accounts of whales scrounging for food in strange places, a record number of documented mortalities, and a historic drop in calf births have triggered alarm bells among whale conservationists and researchers.

Steven Swartz, co-director of Gray Whale Research in Mexico, a nonprofit project that monitors the whales in Mexico’s state of Baja California Sur, has studied marine mammals since 1977. He has tracked population declines that prompted the U.S. National Oceanic and Atmospheric Administration (NOAA) to declare an Unusual Mortality Event (UME), or significant die-off, of members of the eastern North Pacific gray whale from 1999 to 2000 and again from 2019 to 2023. (See "Gray whale deaths prompt a three-nation research effort" —EcoAméricas, July 2019.)

Swartz has also observed gray whales rebound from crises, but he says their prospects might be different this time. “I feel a personal dissatisfaction and sadness with what is going on with them,” Swartz says. “I’m really wondering if they’ll make it out.”

NOAA estimates the eastern North Pacific gray whale population was 12,950 in the winter of 2024-25, less than half the 26,960 estimated in 2015-16 during an interval between the two mortality events. In the first four months of 2025, the NOAA Unusual Mortality Group reported 158 dead gray whales had washed ashore—94 in Mexico, 60 in the U.S. and 4 in Canada. Swartz stresses that these strandings represent a small portion of total whale deaths since the large mammals often die offshore and sink to the bottom of the ocean.

Yet another disturbing statistic was tallied this year with a record low number of northbound mother-calf pairs. These pairs are counted by staff members of the Southwest Fisheries Science Center of NOAA working at the Piedras Blancas Lighthouse Station in central California, an ideal whale observatory situated along the Mexico-Arctic migratory route.

In 2025, Piedras Blancas observers counted only 85 mother-calf pairs, sharply down from 217 pairs in 2024 and the lowest ever annual number since NOAA began tracking migrating whales at Piedras Blancas in 1994.

In August, Swartz and two other leading whale biologists, Jorge Urbán of Mexico and James Darling of Canada, warned in an open letter that the species is on the brink. They said the likely cause is “large-scale ecosystem change” in sub-Arctic and Arctic feeding grounds due to global climate change.

Climate affecting diet

They cite a 2023 study (Stewart, et al.) that examined both the 1999-2000 and 2019-2023 die-off and found changes in the gray whale’s arctic habitat in terms of sea-ice cover, seasonal phytoplankton and sea-ice algae production, and a decline in gray whale prey. A changed availability of the creature’s primary invertebrate prey, benthic amphipods, was also noted.

Urbán, who codirects Gray Whale Research in Mexico with Swartz, underlines that the biggest threat facing the gray whale is in the climate-besieged Bering Sea and Arctic. “The big problem is food sources,” Urbán says.

Located at the southern end of the cetacean’s 16,000-mile round-trip migratory route, Mexico is critical to the gray whale’s survival. There, in the winter, the whales breed and calf at three known sites along Mexico’s Baja Peninsula, then set off to feed in the Arctic in that region’s warm-weather season. To promote protection of two of those sites, the United Nations Educational, Scientific and Cultural Organization (Unesco) in 1993 established a World Heritage Site in Baja California Sur called El Vizcaino Whale Sanctuary.

Escalating gray whale mortalities in Mexico have drawn public attention. In April, the Baja California Sur state Legislature passed a resolution urging government authorities and academics to probe the whale deaths and make the findings public. Such moves reflect concern that a gray-whale population crash would be a major blow to regional biodiversity and a serious economic problem for Baja California Sur.

Gray-whale watching in the state has spawned a vibrant ecotourism industry. Swartz fears the economic fallout from such a crisis would cause losses such as those felt in the state during the early stages of the Covid-19 pandemic, when whale-watching communities saw ecotourism plummet. “They’re really economically on the ropes if the whale population declines [and] there is nothing to see,” he says.

Along the whales’ migratory route to Arctic feeding grounds, veteran whale biologist John Calambokidis and the whale-monitoring center Cascadia Research Collective of Washington state are monitoring another crisis unfolding in real time. They report gray whales are being spotted in unusual places and exhibiting concerning behaviors.

Migration cut short

A sub-group of 200-250 gray whales off the Washington coast, which researchers call the Pacific Coast Feeding Group, stayed put this year and didn’t even make the Arctic migration. This “points the finger at food-related issues in the Arctic,” Calambokidis says. The estimated calf birth rate this year for all whales in the Eastern North Pacific—a historically low 85—pales in comparison to the 1,000-per-year rate in some of the post-UME years. Calambokidis terms the development “alarming.”

Sightings of gray whales jumped this year in California’s San Francisco Bay, a water body the whales formerly avoided. Kathi George, of the nonprofit Bay Area-based Marine Mammal Center, says gray whales began frequenting the bay in 2017. While six individuals were observed in the bay last year, this year they numbered a record 35, of which 21 died, George says. Some whales have been spending up to 60 days in the bay and attempting to feed on the bottom, she adds. Moreover, malnourished and physically weakened individuals are more susceptible to death or injury from ship strikes, George says.

In Mexico, Jorge Urbán and two colleagues have urged authorities to elevate the gray whale from the “special protected” category to “threatened.” They have also called on Mexican environmental authorities to step up best-practice training of whale-tour operators and ensure adequate oversight of whale-watching activities.

Given the pressures felt by gray whales, which sometimes experience close contact with humans, “observations have to be more careful than in previous years because the whales haven’t eaten much,” Urbán says.