Scientists work to identify San Francisco Bay's enigmatic gray whales
In recent years, the number of whales swimming in San Francisco Bay has increased dramatically, often with tragic results.
Why it's happening is still a bit of a mystery, but the painstaking work of one young researcher is helping identify the wayward whales in order to get a better understanding of their behavior.
When Josie Slaathaug chose her Master's research project, she could have selected an easier subject to observe than the gray whale.
"Yeah, I like to make it hard on myself, you know? Add some challenge in there," she said, laughing. "The way that they surface, they really love to just give you a sliver of their body--just the top, never the tail."
Last year, as part of the Marine Mammal Center's internship program, Josie began capturing and reviewing thousands of photographs as a way to catalog the individual gray whales that come into the Bay. Like with fingerprints, she looks for unusual markings, especially on the whales' right side, which has become a kind of scientific standard for identification.
"I oftentimes look for marks in tandem with each other," she said. "So, I'll look for a sequence of marks that I see in a particular order."
It's not easy, as photos of the same animal don't always show the same details. Josie looks for obvious markings, like the large white splotch on a whale they nicknamed "Chips." Another was named Luna because of a moonlike mark on its back. And "Divie" was named for a diagonal slash with a dot above and below that looked like a division sign.
In the past 12 months, Josie has viewed about 17,000 photos dating back to 2018 and has identified and cataloged up to 84 different grays that have visited the Bay since that time. Now, she can easily recognize most of her subjects, even in blurry or grainy photos.
"I'm very confident!" exclaimed Josie. "I take my time and I pore over them, and at the end of my project, there was nobody that knew these whales better than I did. I get so much satisfaction and joy from matching a whale in a difficult photo, and I can still tell who it is...that feeling's the best."
But the project isn't just an academic exercise. The whales have been in trouble for years, washing up on Bay Area beaches, victims of either ship strikes or often starvation.
Bekah Lane heads up the whale research team at the Marine Mammal Center, and said many grays seem to be starting their long migration from the Arctic underfed. So by the time they try to return, they're running out of fuel. That's why scientists believe the whales are now coming into the Bay to desperately forage for food.
"And that's something they didn't really do much of, prior to 2018," said Lane. "But we're seeing them become really flexible in these behaviors, in order to survive and thrive in today's oceans."
In 2019, federal officials declared an "Unusual Mortality Event" as a result of the gray whale die-off. But just this year, that designation ended. The mysterious deaths have largely stopped, and scientists are wondering if the whales are learning to adapt their behaviors to survive the changing conditions.
That's why Josie's work is so important. By cataloging individual whales, researchers can keep track of their comings and goings and answer a number of questions that, at this point, remain 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 into the Bay? Are they not completing their entire migration to the Arctic, and they're sticking around more locally and hanging out as part of the Pacific coast feeding group? Who are these whales, and where do they go when they're not here?"
The answers to those questions may provide insight into how these magnificent creatures are adapting to a changing environment - and whether there's anything we can do to help them survive.