In recent years, the number of whales swimming in San Francisco Bay has increased dramatically, often with tragic consequences.
Why this happens remains a mystery, but the painstaking work of a young researcher is helping to identify the wayward whales and better understand their behavior.
When Josie Slaathaug chose her master’s research project, she could have chosen an easier subject to observe than the gray whale.
“Yeah, I like to make it hard for myself, you know? Add a little challenge to it,” she said, laughing. “The way they surface, they really like to just give you a piece of their body — just the top, never the tail.”
Last year, as part of the Marine Mammal Center’s internship program, Josie began taking and reviewing thousands of photographs as a way to catalog the individual gray whales that enter the bay. Like fingerprints, she looks for unusual markings, particularly on the right side of the whales, which have become a sort of scientific standard for identification.
“I often look for markers in tandem with each other,” she said. “So I look for a series of markers that I see in a certain order.”
That’s not easy, because photos of the same animal don’t always show the same details. Josie looks for clear markings, like the large white spot on a whale they named “Chips.” Another was named Luna because of a moon-like mark on its back. And “Divie” was named for a diagonal line with a dot above and below that looked like a division sign.
Over the past 12 months, Josie has reviewed approximately 17,000 photos dating back to 2018 and has identified and catalogued up to 84 different grey birds that have visited the bay since then. She can now easily identify most of her subjects, even in blurry or grainy photos.
“I’m so confident!” Josie exclaimed. “I take my time and I dig in, and by the end of my project, no one knew these whales better than I did. I get so much satisfaction and joy out of matching a whale to a difficult photo, and I can still see who it is…that feeling is the best.”
But the project is not just an academic exercise. The whales have been struggling for years, washing up on Bay Area beaches, victims of ship strikes or often starvation.
Bekah Lane, who leads the whale research team at the Marine Mammal Center, said many gray whales appear to begin their long migration from the Arctic undernourished. By the time they try to return, they’re running out of fuel. That’s why scientists think the whales are now coming to the bay in desperate search of food.
“And that’s something they weren’t really doing much of up until 2018,” Lane said. “But we’re seeing them become very flexible in this behavior, to survive and thrive in today’s oceans.”
In 2019, federal officials declared an “Unusual Mortality Event” due to the gray whale deaths. But it wasn’t until this year that that designation ended. The mysterious deaths have largely stopped, and scientists are wondering if the whales are learning to adapt their behavior to survive the changing conditions.
That’s why Josie’s work is so important. By cataloging individual whales, researchers can track their comings and goings and answer some of the questions that are currently a mystery.
“Where do these whales go when they’re not in the bay?” Slaathaug asked. “Do they go somewhere else locally and then come back to the bay? Don’t they just complete their entire migration to the Arctic, and then they stay more locally and hang out as part of the Pacific coastal feeding group? Who are these whales, and where do they go when they’re not here?”
The answers to these questions could provide insight into how these magnificent creatures adapt to a changing environment, and whether there is anything we can do to help them survive.
