6 days ago
6 grey whales found dead in San Francisco Bay area in less than a week
Six grey whales have died in the San Francisco Bay area in the past week and authorities are trying to determine what could be causing the sudden deaths of the stranded marine mammals.
The California Academy of Sciences and the Marine Mammal Center confirmed that the whales died between May 21 and 28, and noted that their necropsy response efforts to determine what has been happening is 'challenging.'
'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,' officials said.
'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,' the officials added.
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On May 28, one grey whale was found dead near Alamere Falls. On May 26, two more grey whales were reported dead, with one near Alcatraz Island and another at Point Bonita in Marin County.
A female grey whale died on May 24 near Berkeley and another was found in Fisherman's Bay on Southeast Farallon Island, off the San Francisco coast, on May 22.
On May 21, a yearling grey whale was found dead in Bolinas in Marin County.
The Marine Mammal Centre added that this is the most number of dead grey whales 'since the Unusual Mortality Event that caused this species to lose roughly 45% of their population just a few years ago.'
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'Our team has documented more whales in the Bay this year than any year in at least two decades. A stark reminder that this busy, commercial environment is one we share with our ocean neighbors. We are committed to continuing our work to study these animals and work with stakeholders to find solutions to protect them,' they added.
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People look at the body of a deceased grey whale on the shore in Huntington Beach on April 12, 2025, in Los Angeles, Calif. A dead grey whale measuring about 50 feet in length washed up on the shore in Huntington Beach Friday afternoon, the city's Marine Safety Division said in a social media post. I RYU/VCG via Getty Images
The recent reports of whale carcasses bring the total number of dead whales found in the Bay Area in 2025 to 14.
The California Academy of Sciences confirmed that three of the 14 deaths were determined to be suspect or likely vessel strikes.
'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,' it said in a statement. '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.'
They said that the reason behind the massive spike in sightings this year is still being investigated by researchers.
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'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,' they added.
Officials are warning boaters in the area to be 'whale aware.'
'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,' officials warned.
'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,' scientists continued. '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.'
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People are being urged to report dead, injured or stranded marine mammals in the San Francisco Bay Area by calling the California Academy of Sciences for dead animals or the Marine Mammal Center for live animals. They are also asking the public to report whale sightings to the Whale Alert app or on the Marine Mammal Center's website.
Grey whales have also been washing ashore in British Columbia this month, with a second dead grey whale reported on May 11 in Haida Gwaii, near the community of Skidegate.
The cause of death is unknown, and Fisheries and Oceans Canada say confirming what happened through necropsy reports may take up to three months.
The latest case comes after Parks Canada said a dead whale was spotted floating off Vancouver Island on May 6, before it washed ashore on Long Beach in Pacific Rim National Park Reserve near Tofino.
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Parks Canada says a deceased grey whale, seen in this handout photo, has washed ashore on Long Beach near Tofino, B.C. SDVTHE CANADIAN PRESS/HO-Parks Canada
The federal department has warned people to not touch the dead whales and to keep dogs leashed, and is also asking anyone who sees whales being harassed or disturbed to report to the agency immediately.
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—With files from The Canadian Press
