California Academy of Sciences Confirms Six Dead Whales in San Francisco Bay Area this Week

UPDATE: As of May 29, 2025, the California Academy of Sciences can confirm an additional dead gray whale, the fourteenth so far this year in the greater San Francisco Bay Area region, has washed ashore near Alamere Falls in Point Reyes National Seashore. The numbers below include this individual.

SAN FRANCISCO, CA (May 28, 2025) — The California Academy of Sciences and partners at The Marine Mammal Center can confirm the unfortunate news that six gray whales have died in the wider San Francisco Bay Area region in the last week, bringing the total number of stranded whales in 2025 to 15.

• May 28, 2025: Gray whale, Alamere Falls, Point Reyes National Seashore; undetermined (necropsy conducted on May 28, results pending)
• May 26, 2025: Suspected gray whale, Alcatraz; cause of death: undetermined (no necropsy performed)
• May 26, 2025: Gray whale, Point Bonita; cause of death: undetermined (no necropsy performed)
• May 24, 2025: Subadult female gray whale, Berkeley; cause of death: undetermined (no necropsy performed)
• May 22, 2025: Gray whale, Fisherman’s Bay, Southeast Farallon Island; cause of death: undetermined (no necropsy performed)
• May 21, 2025: Yearling gray whale, Bolinas; cause of death: undetermined (partial necropsy conducted on May 23, inconclusive)
• Necropsy response efforts and data collection have been challenging for a number of cases due to inaccessible locations that hinder full post-mortem investigations, as well as poor tissue quality from advanced decomposition, and the lack of available locations to tow for further investigation.
• As of today, May 28, 2025, a necropsy (animal autopsy) was conducted at Kirby Cove in the Marin Headlands. It is suspected that this subadult male is one of the two whales that was sighted on May 26, 2025. The cause of death is still under investigation. The other individual has not made landfall.

In 2025, 14 gray whales and one minke whale have died in the greater San Francisco Bay Area region, with the cause of three of the gray whale deaths determined to be suspect or probable vessel strikes. The Academy and partners at the Center have not responded to this many dead gray whales since the height of the Unusual Mortality Event in 2019 (14 individuals) and 2021 (15 individuals).

The Center’s Cetacean Conservation Biology Team has reported an unusually high number of sightings in the San Francisco Bay this year, with 33 individual gray whales confirmed via photo identification. By comparison, only six gray whales were sighted in the bay in 2024. Roughly one-third of these whales have stayed in the bay for at least 20 days, and their overall body condition has ranged from normal to emaciated. The reason or potential reasons behind the massive spike in sightings this year are still being investigated by researchers. It is expected that gray whales will be in the bay for another one to two weeks before continuing their annual northern migration to arctic feeding grounds.

The long-term outlook for eastern North Pacific gray whales in the aftermath of the 2019-2023 Unusual Mortality Event (UME), which saw a population loss of roughly 45 percent, is unclear. Research partners in Mexico, Canada, and the United States are actively monitoring population health to gain further insights in the aftermath of a second UME in 20-plus years. Observation scientists in southern California reported record-low calf counts earlier this year, which is a cause for concern.

With San Francisco Bay serving as a shared space for commerce and increased gray whale activity, experts at the Academy and the Center note it’s vital that all boaters—from large commercial vessels to sailboats—be “whale aware” and continue to slow down. Gray whales often have a very low profile in the water that can make them difficult to sight, unlike other coastal whales like humpback whales. The Center is working with the San Francisco Harbor Safety Committee to find solutions to reduce the risk of vessel strike (including altering ferry lanes based on sighting data this year) and increase mariner communication announcements of heightened whale activity via the U.S. Coast Guard.

All marine mammal stranding activities were conducted under authorization by the National Marine Fisheries Service through a Stranding Agreement issued to the California Academy of Sciences (SA-WCR-2023-016) and MMPA/ESA Permit No. 24359.

Resources
If you do see a whale in the bay or surrounding area, you can report the sighting and enter observations into the free Whale Alert app on your smartphone or to the Center’s website. For dead marine mammals, please contact the Academy's department of Ornithology and Mammalogy here.

Historical stranding data, as well as a regularly-updated interactive map of the Center’s necropsy responses with the Academy from this year can be found here. Please note it includes responses outside of the San Francisco Bay Area.

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Video and photo assets can be found here.