When orcas and white sharks cross paths, only one can prevail as the true apex predator. New research from the Monterey Bay Aquarium published in Nature Scientific Reports details these rare, sometimes brutal encounters — and their ecological implications.
It’s a study decades in the making because observations of the two creatures interacting is a rarity.
Scot Anderson, a white shark expert and seasonal researcher for the Aquarium, still remembers one such run-in more than 20 years ago near the Farallon Islands, a short boat ride west of downtown San Francisco.
“The first time it happened was kind of shocking to everybody,” Scot says. “Before we had seen anything like that, people would ask, who’s the baddest predator?”
The first scorecard came on October 4, 1997, when orcas killed and partially ate a white shark within view of a whale-watching boat. Scot was heading out from nearby Bolinas when he heard what was happening over the radio.
Monterey Bay and surrounding waters are prime habitat for white sharks. The same adult white sharks visit this part California annually over decades, mostly during fall and early winter. Farther south, from Santa Barbara to Central Baja, white shark babies, or pups, typically spend their first years in warmer “nursery” waters.
What’s new and surprising, though, is that in recent years a seasonal group of younger white sharks has established itself within sight of the beaches at the north end of Monterey Bay. Is this new cohort taking up residence as a result of warming ocean conditions? And why are the sharks aggregating in one portion of the bay?
For nearly 34 years, Monterey Bay Aquarium has harnessed the power of science to guide every aspect of our work—exhibit development, public policy and outreach, sustainable seafood solutions, research and education programs. In 2017, the Aquarium became one of the first 100 partners to support the first March for Science as a way to share our dedication to the scientific process. As the 2018 March for Science ramps up on April 14, we thought we’d revisit some of our greatest moments in marine conservation science over the last year. In these, and many other ways, we’re harnessing the power of science to make our world a better place.
Dynamic tuna dorsal fins
While observing Pacific bluefin tuna inside the Tuna Research and Conservation Center (TRCC), scientists noticed something…fishy about the way they were swimming. TRCC scientists logged hours of video footage and, after conducting routine medical exams, discovered that the dorsal fins of tunas move both forward and backward as they swim—especially when they hunt for prey in quick flashes of speed. Their work, reported in a cover article published in Science magazine, documented that the team of scientists discovered a hydraulic mechanism that allows a tuna to articulate its dorsal fin along a range of angles depending on which behavior the tuna exhibits.
Sea turtles use flippers like fingers
When evolution, animal behavior and body form meet in one elegant space, we call it “ecomorphology,” an area of expertise for Aquarium senior research biologist Jessica Fujii, who for years has studied how and why sea otters use tools. But when Jessica and her colleagues observed that sea turtles use their flippers like tools to swipe, slice and corral their food, we might call that “evolutionary serendipity”—something that sea turtles did not necessarily evolve to do, but do anyway. In a recent study published in PeerJ and led by Jessica, we learned that sea turtles use their flippers, largely designed for locomotion, to manipulate their prey. The scientists tapped crowdsourced images and videos from around the world to document turtles prying open scallops and karate-chopping jellyfish, confirming that this ancient marine reptile need not have a frontal cortex to perform such complex maneuvers. Because transparency is a key tenet of scientific inquiry, our team decided to make both the paper and the peer reviews of the paper available free to anyone with internet access.
Museum feathers reveal seabird diet changes
Naturalists hiking around the islands of Hawaii in 1890 could never have guessed that the seabird feathers they collected would someday be used to help tell the story of a changing ocean. But for Aquarium researcher Tyler Gagne, lead author on a new study of how seabird diets have changed over the last 130 years, the feathers played a vital role in reconstructing what seabirds have—and have not—been eating. Using stable isotope analysis, Tyler and his team traced specific chemical signatures found in the preserved seabird feathers to show how, over time, eight different species in the North Pacific have shifted from fish to squid, a transition that suggests both human and climate impacts are influencing their dietary choices.
The data behind sea otter rescues
For more than 30 years, sea otter researchers and animal care specialists at the Aquarium have been tagging, tracking, rescuing and rehabilitating stranded adult sea otters and pups. The data collected from 725 live strandings between 1984 and 2015 provide an intricate portrait of major threats California sea otters face as their population slowly recovers. Aquarium researchers determined that the absence of significant kelp canopy coverage at the peripheries of the sea otter range, especially in waters north of Santa Cruz and south toward Point Conception, can inhibit sea otters’ ability to reproduce and survive. Without sufficient kelp cover, sea otters, especially reproductive females and their pups, can be left vulnerable to shark bites.
Young white sharks: the wonder years
After years of studying the underwater lives of white sharks, Aquarium researchers and their partners in the United States and Mexico noticed some missing links in the life history of these apex predators. Where do white sharks give birth, and where do their pups grow up? Thanks to a study published in Fisheries Research, scientists discovered that Bahia Sebastián Vizcaino, a warm lagoon on the coast of Baja California, is a nursery for newborn white sharks. This study formalized a de facto understanding that southern California was the place to find young white sharks, but researchers validated a more surprising fact about juvenile white sharks: they don’t stay in Californian waters and they regularly travel to Mexican waters and back again.
These are just a few highlights reflecting the growing scope of ocean science taking place at the Aquarium. We’ll continue to conduct new science every day, to inspire new generations of science-literate citizens, and to use the best-available science to inform everything we do to assure a bright future for our ocean planet.
For more than 30 years, the Monterey Bay Aquarium has been a key contributor to sea otter recovery in California. Aquarium researchers and policy experts have advanced scientific knowledge, promoted improved management and raised public awareness of the contributions sea otters make to healthy coastal ecosystems. A new research paper in the journal Ecography draws on three decades of Aquarium research to establish a link between sparse kelp cover along the California coast and a recent rise in sea otter mortalities from white shark bites. The finding illuminates a new challenge for everyone working toward sea otter recovery: Will sea otters be able to run the gauntlet of white sharks and expand back into their historical range without human assistance? Conservation Research staffer Athena Copenhaver explores the challenge.
Senior research biologist Teri Nicholson fans out her left hand, tapping each finger as she recites a brief list of unusual names: Jiggs, Goldie, Hailey, Milkdud . . .
They might sound as though they belong to beloved pets, but Teri is actually recalling the stranded southern sea otter pups taken in by Monterey Bay Aquarium back in 1984.
Although Teri and her colleagues didn’t know it at the time, these first four orphaned pups became foundational data points in a pioneering sea otter study that spans the lifetime of the Aquarium.
“By rescuing and rehabilitating stranded animals, we can observe symptoms and determine possible reasons the animal might have stranded,” explains Teri. “And, that means we can look for patterns in threats otters face over time.” Continue reading Sea otters’ perilous path to recovery
Southern sea otters are a common (and adorable) sight off the Aquarium’s back deck. But the latest otter count shows the population isn’t growing at the pace we’d hoped it would. In order for the species to truly recover, otters need to return to their old habitats along California’s coast—places they haven’t inhabited for over 100 years.
But the 2017 sea otter count is down quite a bit from 2016 levels, and even the three-year rolling average (the population index), on which federal wildlife managers base their decisions, is down by about 100.
Regardless of year-to-year variations, southern sea otters number far fewer today than they did historically, and their current geographic range represents just a fraction of the waters they occupied before fur traders drove them to the brink of extinction in the 19th century.
To reach the optimum sustainable population under the Marine Mammal Protection Act and the Fish and Wildlife Service recovery plan, the southern sea otter population would likely have to reach at least 8,400 animals in California alone.
“What we really want to see is the population reinhabiting areas of its historical range,” says Andrew Johnson who, as conservation research operations manager for Monterey Bay Aquarium, oversees the sea otter program. “We’ve seen how positively coastal ecosystems respond to the presence of sea otters—from the return of thriving kelp beds along the rocky coast, to renewed productivity of wetlands like Elkhorn Slough. We know that many other areas along the California coast would benefit significantly from sea otters’ return.” Continue reading California’s sea otters need more space to grow
The Monterey Bay Aquarium is a science-driven organization, and rigorous science underpins all of our public policy, research and education programs. Much of our research centers on marine life that visitors can also see in our exhibits – from sea otters to sharks and tunas, even our giant kelp forest. Here’s some of what we’ve learned over the past 30-plus years that is contributing to conservation of key ocean species and ecosystems.
Sea otters crack open tool-use secrets
Revolutionary female scientist Jane Goodall was the first person to discover that chimps use tools and live within complex social systems. Our team of female researchers are walking in Jane’s footsteps with their recent studies on use of tools by another mammal: the sea otter. When observing sea otters along the Monterey Peninsula, sometimes we can hear a “crack, crack, crack!” above the roar of the tide. That sound comes from sea otters using rocks and other tools to open prey items, such as crabs or bivalves, as they float on their backs. Sea otters are avid tool users, but until recently not much was known about how sea otters choose their tools, what aspects of their environments influence tool use, or whether they teach tool use to other otters. The Aquarium’s decades of research into sea otter behavior provided years of observations of sea otter foraging and tool-use behavior, including sea otter pups pounding empty fists against their chests. Could such activity be instinctual? Research Biologist Jessica Fujii has devoted much of her young career to studying the frequency and types of tools used and whether tool use can be coded in sea otter genes. Jessica is looking ahead to see how sea otters learn, teach, and eventually master tool use in the wild.
Sea otter surrogacy helps restore Elkhorn Slough
With 15 years of experience rescuing, rehabilitating, and then releasing surrogate-reared sea otters into Elkhorn Slough, an estuary near Moss Landing, California, the sea otter research team at the Aquarium began to wonder how and if their work was affecting the otter population there. Does releasing a few animals into the slough each year really make any difference? After crunching some serious numbers from the surrogacy program and the U.S. Geological Survey’s (USGS) annual sea otter census, the researchers discovered that it did. Nearly 60 percent of the 140 or so sea otters living in Elkhorn Slough today are there as a result of the Aquarium’s surrogacy program. While we’d known that sea otters served as ecosystem engineers for the giant kelp forests in Monterey Bay, we have now documented that sea otters in Elkhorn Slough are restoring the health and biodiversity of the estuary. This gives us further insights into how sea otters may contribute to coastal ecosystem resilience. Continue reading Using science to save ocean wildlife
Monterey Bay Aquarium has since its inception affirmed that we are a science-driven organization, and that science underpins all of our public policy, research and education programs. That’s why we’re a partner with the national March for Science, a series of more than 500 events around the world on April 22.
As part of our commitment to the scientific process, our white shark research team works to understand and conserve these vital ocean predators. In advance of the March for Science, we’re taking a look at many of our scientific initiatives—in research, policy and education. Here’s a look at some of our recent white shark science highlights.
Annual Field Research
Every fall for the last decade, the Aquarium’s white shark research team has headed out to the Farallon Islands off the coast of San Francisco to tag, track, and identify white sharks as they feed on elephant seals and sea lions. The team observes behavior, captures underwater video, and deploys electronic tracking tags that relay information about white shark migrations and habitat preferences. When the team returns to the lab, they combine and analyze all these data to better understand white shark populations and their role in maintaining the healthy ocean ecosystems that ultimately support all life on Earth.
It’s relatively easy to spot when and where a pregnant animal gives birth on land. But in the sea, it’s a whole different story.
Over the past few decades, researchers studying the elusive great white shark have pieced together a picture of their underwater lives: The adults seasonally travel between a remote region of the Pacific Ocean—dubbed the White Shark Café—and their feeding grounds in Central California and Mexico.
But where do females give birth, and where do the offspring grow up?
“We don’t know whether [the sharks] pup in-shore or off-shore,” explains the Aquarium’s Director of Collections John O’Sullivan. “We don’t even know whether they pup in American or Mexican waters.”
But in a paper recently published online in the journal Fisheries Research, scientists have revealed a new piece of the juvenile white shark puzzle. The study—an international collaboration between researchers at the Ensenada Center for Scientific Research and Higher Education (CICESE); Monterey Bay Aquarium; California State University, Long Beach; and other institutions—revealed that Bahia Sebastian Vizcaino, a warm lagoon on the coast of Baja California, is a nursery area for newborn white sharks.
As 2016 comes to a close, let’s look back at the top 10 highlights from this blog:
10. Camera to Crack a White Shark Mystery: Our senior reseach scientist teamed up with the Monterey Bay Aquarium Research Institute for a high-tech mission: to capture video footage of great white sharks in their most mysterious habitat.
“Some of the engineering team said it was an impossible job,” MBARI Engineer Thom Maughan recalled. “But I’m attracted to those opportunities.”
Monterey Bay Aquarium’s white shark tagging team recently made its annual visit to the Farallon Islands outside San Francisco Bay. The goal: to continue its long-term efforts to monitor a genetically distinct population of adult white sharks, which gathers at the islands each fall to gorge on seals and sea lions.
During the trip, team members took photos to identify individual sharks by their dorsal fin patterns, collected tissue samples for genetic research, and attached electronic tags to study these majestic ocean predators. Presley Adamson, associate producer and editor for the Aquarium’s film team, reports back on his experiences in the field.
It’s been two hours since we lost sight of the Golden Gate Bridge and, with it, any sign of civilization. Dr. Salvador Jorgensen, senior research scientist for Monterey Bay Aquarium; and Scot Anderson, a pioneering white shark expert and seasonal researcher for the Aquarium, are somehow sleeping through the relentless rocking and rolling of our sailboat. I’m too excited to sleep.
Choppy waves have kept us stuck on shore for six straight days. Today, the waters are finally calm enough for us to cross the 25 miles of open ocean between San Francisco and the Farallon Islands.
The Farallones are technically part of the City of San Francisco, but we won’t find any subdivisions or grocery stores here. The islands, their surrounding waters, and their plant and animal inhabitants are protected in the Farallon National Wildlife Refuge, within the Greater Farallones National Marine Sanctuary.
More elephant seals and sea lions than people visit the Farallones. The abundance of blubbery pinnipeds attracts some of the largest white sharks in the world, who hang around the islands looking for a meal.
Sal and Scot have brought me along to document this year’s research season. I’m armed with six cameras that need to be set up before we get to the Farallones. I also need to put on foul-weather gear—boots, life jacket, raincoat, and other gear to stay warm and dry. But I’m distracted by a pod of humpback whales next to our boat, showing off their giant flukes as they go about their own morning commute.
I can just start to make out a lone pinnacle emerging from the sea. We’re almost there.