Of the six that died this week, researchers suspect that at least three of the deaths were caused by vessel or boat collisions. Another gray whale that died in April was also suspected to have died from a collision. It was found with six fractured vertebrae.
Experts are working with the San Francisco Harbor Safety Committee and local ferries to figure out how to safely navigate areas occupied by whales. Part of the solution could be changing routes during whale season based on where the animals are typically observed, Rulli said.
“There are a lot of added threats within the bay,” Rulli said. “You have a large number of whales accessing a very enclosed body of water with large mariner vessels of many types … Keeping whales safe while they are here, typically from late February to beginning of March for gray whales, is something that experts here at the Marine Mammal Center are working really closely on.”
It’s been a weird year for conservationists and whale experts in the bay.
More than 30 individual gray whales have been spotted in Bay Area waters this year, compared to the four seen in all of 2024, Rulli said. Roughly one-third of the whales have stayed in the bay for nearly a month, and it is expected that they will remain in the area for one or two more weeks before continuing their northward migration.
While some of the whales are in good condition, others show signs of being malnourished or emaciated, Rulli said. Their behaviors also differ from one another, making it hard for researchers to determine what’s going on during this migration season, he added.
Rulli encouraged members of the public to report any whale sightings in the San Francisco Bay by using the Whale Alert app or through the Marine Mammal Center’s website.
KQED’s Samantha Kennedy contributed to this report.
