When Bill Keener started working as a field biologist at the Marine Mammal Center in the 1970s, there were no whales or dolphins in San Francisco Bay. The waters east of the Golden Gate Bridge are teeming with life—sea lions and harbor seals abound—but no cetaceans are to be seen.
Starting in the late 2000s, things began to change.
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Four species of cetaceans now live in or frequent the busy waters east of the Golden Gate – harbor porpoises, gray whales, humpback whales and bottlenose dolphins.
Yet Keener and other ocean researchers aren’t sure whether the animals’ presence is a sign of ecosystem health and revitalization or a harbinger of disaster for the planet. In each case, the story is slightly different.
Bill Keener searches for gray whales in the Marin Headlands in May.
(Loren Elliott/The Times)
Whatever the reason for their return, they are increasingly concerned that as the numbers of these charismatic giants increase, so will their risk of injury and death in these heavily trafficked waters.
“We have one of the busiest ports on the West Coast, 85 private and recreational marinas, high-speed ferries and a lot of boat traffic,” said Kathi George, director of cetacean conservation biology at the Marine Mammal Center. “The presence of these animals is cause for celebration, but also cause for concern.”
harbor porpoise
Take the harbor porpoise, for example.
Keener said these friendly, blunt-nosed, dolphin-like animals have been a fixture in the bay for thousands of years. That is, until they stop doing it.
A World War II-era photo shows warships in San Francisco Bay.
(Bateman Archives)
Evidence from the Ohlone shell middens—large pits of discarded bones and shells found throughout the Bay Area—suggests that while they were once plentiful, they either died out or died in the 1940s as the United States ramped up its defenses during World War II. A collective escape. Fearing enemy submarines, the Navy stretched a huge steel net across the bay to prevent underwater ships from sneaking in.
Whether it’s the physical presence of the net or the clanking and din it makes underwater (which Keener says can be really loud), the porpoise has been missing for more than 60 years.
What brings them back is not entirely clear. This may be partly due to the effectiveness of the gillnet ban in the 1980s, which allowed finless porpoise numbers to grow. They may also have been tracking food sources. Once the dolphins get in, they think it’s a good place to settle.
Whatever brought them in, they’re here to stay – they’re a common spot for splashing and diving on the edge of Kirby Bay or around the Cape Diablo Lighthouse peninsula.
Humpback whales
Last year, a humpback whale’s tail fin rose from Monterey Bay.
(Brian Vanderbrugge/Los Angeles Times)
Humpback whales may also be good news—although unlike porpoises, they may never have been permanent residents of San Francisco Bay. There is no evidence of them in the shell piles, and there are no historical reports of them in the bay.
But they’ve always been a coastal presence, migrating in the summer from their wintering grounds in Mexico and Central America to California, where they gorge themselves on fish and krill along the coast. However, due to whaling, their numbers had been reduced to approximately 2,000 individuals by the early 1970s.
Since then, however, their population has swelled to 20,000.
“That’s what happens when you stop hunting them,” Keener said.
In 2016, for the first time in living memory, large numbers of humpback whales followed a dense school of anchovies into the bay. Since then, they have become summer regulars.
gray whale
A gray whale surfaces with its eyes open in Lake San Ignacio, Baja California, where the species gives birth and nurses its young.
(Carolyn Cole/Los Angeles Times)
The story of the gray whale can be a bit ominous.
As with humpback whales, there are no historical records indicating that these singing whales had any significant historical presence in San Francisco Bay—save for a skeleton found in a 2,500-year-old shell mound and Spanish missionary reports of gray whale spouts in San Francisco Bay. A historical report on water.
But in 1999, they began to appear—just as an unusual die-off occurred that nearly halved the number of East Pacific gray whales by the end of 2002.
After the mass strandings subsided and the population began to grow again, they were never seen again – just once or twice a year – until another mass die-off occurred in 2019.
This time, however, the whale still appears to be nearby. This year, 16 whales have been spotted in the bay, one of which has died.
Last month, Marine Mammal Center interns Nicole Cristales (left) and Norely Faz, working under NOAA permit 24359, submerged their GoPro cameras in the water in an attempt to identify a dead gray whale in San Francisco Bay near Richmond.
(Loren Elliott/The Times)
But this time, they’re doing something Keener and others say is a little unusual: They’re eating.
Normally, gray whales only feed in Arctic and sub-Arctic waters during the summer, when the frigid seafloor teems with life and millions or even billions of tiny shrimp-like creatures that the whales scoop up in their massive jaws. The whales feast all summer long before embarking on the 6,000-mile journey south to Mexico, where females give birth and nurse their calves in warm, protected inlets along the Baja Peninsula.
Once they leave the Arctic, they don’t feed again until the following year.
But researchers and observers have seen them diving and foraging for food in San Francisco Bay, as well as lunging, a humpback feeding style in which they open their mouths and lunge toward the surface to catch fish and other creatures.
While this could be a worrying sign—that their usual feeding grounds are no longer productive, possibly due to extreme climate changes occurring in the Arctic and oceans—Keener likes to view it in a more positive light.
The feeding behavior “suggests that the whales may be hungry and that they are looking for other food sources,” he said. “But it also shows that they’re resilient, that they can change their behavior and do things that they’re not known for. That’s actually a good sign.
Keener noted that these animals survived dramatic swings in climate, such as during the Ice Age. This flexibility may be “what allowed them to keep going as they responded to various environmental changes in their feeding grounds during the Ice Age and over the past few thousand years.”
That bodes well for the species, he said, as climate change disrupts vast ecosystems around the world.
He said their work showed that whales’ stops during migration were not just random. Some people come back again and again, leading him and his colleagues to think “some of them are learning about our local scene, figuring out how to navigate and find food. You know, just by living in our area.”
bottlenose dolphin
The now frequent sightings of bottlenose dolphins may also be one of those silver linings.
Typically considered a more common warm-water species in Southern California, they began moving into the San Francisco Bay as dolphins around 2008. ), and by 2000, their range began to spread northward.
Keener said there are no groups of residents in the bay, but “they do visit.”
Keener said the Marine Mammal Center has compiled a local photo identification catalog that includes 120 adult mammals. Some have been identified as dolphins in Southern California in the 1980s. Dolphins are everywhere, he said — a famous female was spotted cruising Monterey waters in the spring, and just last week they were hanging out near Sea Ranch in Sonoma County.
“She does move around, and that’s normal,” Keener said.
Big picture of busy bay
A high-speed ferry sails across San Francisco Bay. Ship strikes are one of the risks to marine megafauna.
(Loren Elliott/The Times)
While this observer of the rapidly changing ocean and the atypical behavior of its inhabitants remains hopeful on a grand, existential scale, he and others worry about the fate of these fascinating sea creatures in the busy shipping lanes of San Francisco Bay. More immediate security.
None of the animals are on the endangered species list, he said, but that doesn’t stop him and his colleagues from worrying, “especially if they get into the bay, where it’s dangerous for them. There’s just too much ship traffic.”
George of the Marine Mammal Center said the Bay Area has large swathes of water without voluntary ship speed reduction zones — a tactic used elsewhere by conservationists, ports and shipping companies to reduce the likelihood of ships striking whales. .
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But George said she and other conservationists are working with the Port Safety Commission, which she said has been receptive and is working to develop a formal plan to protect the animals.
“I’m very excited about the collaborations that are happening and continuing to grow,” she said.
