A gray whale that has been staying in San Francisco Bay since February, in a detour from its normal northward migration, and has spent far more time in the bay than any other whale scientist has observed.
The previous record for a gray whale in the bay was 46 days. Now, with this grey, it’s 67 days.
Bekah Lane, a whale field research specialist at the Marine Mammal Center, said gray whales “appear to be moving deeper into the Bay, even near Oakland and Alameda, and are spending more time in the Bay than in previous years.”
Since the beginning of the migration season, scientists at the Marine Mammal Center in Sausalito have identified at least eight gray whales and one humpback whale in the bay, including the gray whale that has been resident there since February 9.
San Francisco kayaker RJ Andrews spotted a whale on a paddle out of Crane Cove Friday morning for the first time in years of kayaking in the area, which he described as “exhilarating”.
“I can’t say I want to see it because it’s not good for the whales,” said Andrews, 38, who isn’t sure if it was a humpback whale or a gray whale. “But when I do, it’s quite an exciting thing.”
The behavior of the whales worries scientists.
Hanging out in the bay, a relatively new phenomenon, “isn’t part of what we know as a gray whale’s normal migration,” Lane said.
Humpback whales arrived in San Francisco Bay in 2016 and gray whales followed in 2019. For gray whales, this marks a stopover on their normal migratory route from breeding grounds in Baja California to feeding grounds in Alaska, usually crossing the bay between mid-February and mid-May. In the case of humpback whales, the new behavior is likely due to one of their favorite prey species, anchovies, migrating closer to shore following an ocean heatwave in the mid-2010s.
While humpback whales tend to come into the bay briefly to feed, gray whales often stay much longer because they’re tired or hungry — scientists don’t quite understand why. But they can’t find enough food on the Bay, which doesn’t have the same high quality food as Alaska. Overall, the whales’ physical condition has deteriorated since they entered the bay in 2019, Lane said.
Whales can be identified by specific markings on their tail fins, such as fingerprints. In photos over time, including when it was last sighted on April 17, the record-breaking gray whale has shown signs of deterioration, including weight loss and abundance of sea lice, an indicator of greater health problems, Lane said.
The whales’ new patterns have put them in danger, with frequent whale deaths being attributed to ship attacks. Two gray whales washed ashore dead this month, one in Bolinas and one in San Leandro, and both were likely killed by a ship, according to the Marine Mammal Center.
Andrews, a former college rower, makes a 3-mile loop out of Crane Cove several times a week and almost always sees a sea lion or seal. On Friday he first saw what he believed to be a whale spray near Oracle Park and then paddled south and finally saw the whale himself.
“It was this big black mass,” he said, thinking to himself, “‘This whale is moving much faster than I could follow it.'”
Despite having a new high-performance carbon fiber paddle, he never got closer than 300 meters from the whale. Soon it had ventured onto Oakland.
Andrews then became concerned about the whale due to the heavy traffic in the bay and contacted the Marine Mammal Center.
“When you see all these boats going so fast,” he said, “they don’t know there’s a whale sailing under them.”
To report a whale sighting, call the Marine Mammal Center’s 24-hour helpline at 415-289-7325 or go to https://www.marinemammalcenter.org
Reach Tara Duggan: tduggan@sfchronicle.com; Twitter: @taraduggan
