Conservation & Science

New insights to help young white sharks survive

What can scientists studying white sharks learn from an expert on mountain lions? As it turns out, quite a lot.

Monterey Bay Aquarium and its research colleagues have been tagging juvenile white sharks in southern California since 2002. Now they’ve gained new insights into white shark survival from those data tags. Photo courtesy Steve McNicholas

Such a collaboration is on display in new research published in the Journal of Applied Ecology. Models that estimate survival rates for top predators on land, according to the study, can also work in the ocean. The research also revealed important safeguards that can help protect white sharks while they’re young and vulnerable.

At the heart of the effort was the work of lead author John Benson. Before taking his current role as a professor at the University of Nebraska, John was a post-doctoral researcher at the Monterey Bay Aquarium, working with senior research scientist Sal Jorgensen.

Young white shark on exhibit at Monterey Bay Aquarium.

“We always learn things from adjacent fields,” says Sal, who specializes in white sharks, and who coauthored the paper along with six others. “John made his name studying mountain lions in Southern California.”

John’s past work also involved black bears in Louisiana, panthers in Florida, wolves and coyotes in Canada, and moose and their various predators in Alaska. After so much experience on land, John saw working with Sal at the aquarium as a chance to—as the saying goes—get his feet wet. Read more…

Vote #YesOn68 to support California’s ocean and coast

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Prop 68 would improve public access to beaches along California’s 840-mile coastline.

We owe it to our children and grandchildren to protect what we love about California—like our iconic coastline, diverse marine habitats and abundant wildlife.

That’s why Monterey Bay Aquarium is supporting Proposition 68 on the June 5 California ballot. Please join us in voting YES for the future of our ocean!

Proposition 68 is a bond measure that asks voters to approve a $4 billion investment in important natural resources. It is the first bond measure of its kind in more than a decade. If passed, it will help improve public access to California’s coast, boost our state’s resilience to climate change, and protect our ocean and coastal habitats.

Read more…

SOS for South African penguins

Aviculture Curator Aimee Greenebaum worked with the Monterey Bay Aquarium’s African penguins for more than a decade before ever seeing one in the wild. She was in South Africa last fall to help rehabilitate sick and injured penguins and feed starving chicks. She’s quick to point out that it’s less glamorous than it sounds.

Aviculture Curator Aimee Greenebaum spent long days force-feeding fish to rescued penguins. Photo by Richard Kruger.

“They don’t smell good, I’m not gonna lie,” Aimee says with a laugh. But, she adds, “They’re pretty cool. They’re tough little birds.”

Aimee worked for several weeks with the South African Foundation for the Conservation of Coastal Birds (SANCCOB)—the leading conservation organization working to recover this endangered species. African penguins, which stand around two feet tall, don’t hail from the land of snow. The weather at the southern tip of the continent is a lot like Monterey, Aimee says.

Up to 80 rescued penguins per pen awaited a meal from volunteers like Aviculture Curator Aimee Greenebaum. Photo by Richard Kruger

She spent hours each day hunched on a stool, in pens that held 70 or 80 rescued penguins, corralling one bird at a time between her knees. Many required force-feeding.

“These are wild penguins,” she explains. “Our penguins on exhibit know to take fish from our hand. Wild birds aren’t going to do that.” Read more…

Voyage to the White Shark Café

For nearly 20 years, researchers from Monterey Bay Aquarium and Stanford University have fitted electronic tracking tags on adult white sharks each fall and winter along the California coast around San Francisco Bay. Each year, the tags documented a consistent migration by the sharks to a region more than 1,200 miles offshore—halfway to Hawaii—that’s been considered an oceanic desert. They dubbed it the White Shark Café, guessing that opportunities to feed and to mate might be the draw.

Now a team of scientists will spend a month at the Café in a month-long expedition to learn why the sharks make an epic annual migration to such a distant and seemingly uninviting location. The multi-disciplinary team is bringing an impressive complement of sophisticated oceanographic equipment, from undersea robots and submersibles to windsurfing drones that will search signs of sharks and their possible prey.

Funded by the Schmidt Ocean institute (SOI), the team is led by Stanford University Professor Barbara Block and includes marine biologists and oceanographers from Stanford University, Monterey Bay Aquarium, Monterey Bay Aquarium Research Institute (MBARI), the University of Delaware, and NOAA’s Office of Ocean Exploration and Research.  They are traveling aboard the SOI research vessel Falkor and set sail from Honolulu on April 20. They will return to port in San Diego on May 19.

Unraveling a mystery

We’ve studied these sharks for nearly 20 years, and they’ve told us consistently that the White Shark Café is a really important place in the ocean—but we’ve never known why,” said Dr. Salvador Jorgensen, a senior research scientist and shark research lead at Monterey Bay Aquarium.

Sophisticated oceanographic monitoring tools like these Saildrones will collect data to document the presence of white sharks and their prey species in the cafe. Photo courtesy Schmidt Ocean Institute.

By documenting the biology, chemistry and physical conditions in the region—a swath of the Pacific Ocean the size of Colorado—the researchers hope to understand what makes the Café an annual offshore hot spot for one of the ocean’s most charismatic predators. Read more…

Untangling the mysteries of deep-sea food webs

Stretching more than two vertical miles from the seafloor to the ocean’s surface, the water column is Earth’s biggest habitat by volume. For researchers trying to untangle its complex, multi-tentacled food web—the way energy flows from one ocean denizen to the next—it’s a vast and challenging realm in which to accomplish this task.

A gonatid squid eats a deep-sea fish. These types of predator-prey relationships were easier to document, leading marine biologists to undervalue the “who eats who” complexity of predation by more delicate gelatinous animals. Photo © MBARI

Recent work by scientists at the Monterey Bay Aquarium Research Institute (MBARI) has revealed whole new layers of predator-prey interactions in the water column, particularly in the often overlooked roles played by jellies and other soft-bodied animals—many of which, researchers discovered, feed on their own kind.

This research is promising, says Anela Choy, the biological oceanographer who led the study, but much more remains to be discovered about deep-sea food webs.

“I wish I knew just how much there was that we didn’t know,” she says. “That’s what keeps us all going.”

New appreciation for jellies

Many feeding interactions in the deep sea are difficult to observe because they take place in total darkness, thousands of feet below the surface, in cold, crushing conditions that test even the capacities of MBARI’s advanced robots. Before the advent of robotic exploration technology, much of what scientists gleaned about food webs was gathered from animals hauled to the surface in nets—or discovered in a predator’s guts.

High-definition video cameras captured this image of a helmet jelly eating two types of prey: a small squid and (on its bell) another species of jelly. Photo © MBARI

One problem with that approach, Anela says, is that squishy animals like jellyfish and other gelata, while among the most prevalent life forms in this ecosystem, almost never make it to the surface intact.

“They’re really hard to capture—that’s the traditional way of studying diet, is to capture those animals and look in their stomachs,” she says. “With a net, they often immediately break apart. “If they are the predator of interest, we cannot ascertain their gut contents this way because they are very damaged.”

Obstacles to overcome

There are other obstacles to understanding food webs. The traditional way of studying diet is to capture an animal and look into its stomach to see what prey have been eaten. Anela notes that gelata digest very quickly and thus are often missed with diet work.

MBARI’s remotely operated vehicles, like the Doc Ricketts, have recorded video documenting hundreds of feeding interactions in the deep sea. Photo © MBARI

So Anela and her MBARI co-authors, Steve Haddock and Bruce Robison, tried a different approach.

The high-definition cameras on MBARI’s diving robots have recorded thousands of deep-sea animal observations since 1989. All of the video has been rigorously archived to reflect its subject, location, time, depth and even water temperature and other physical parameters. From this footage, Anela and her colleagues gleaned a wealth of information: 743 documented instances of undersea creatures eating, being eaten, or having just fed.

(Anela singled out two video technicians at MBARI, Susan von Thun and Kyra Schlining, who “watched every single hour of videotape from every midwater dive” to build an unprecedented underwater feeding dataset.)

Hundreds of feeding observations

From the video, the team tallied 242 unique kinds of predator-prey relationships. Many involved jellyfish and other soft-bodied animals, which don’t seem to particularly mind having a robot watch them eat, and which are often transparent, meaning the researchers could easily peer inside their bodies to view their most recent meal.

This complex food web shows groups of animals (indicated by different colored circles and lines) that were observed eating each other during MBARI remotely operated vehicle dives. Thicker lines indicate more commonly observed predator/prey interactions. Illustration © 2017 MBARI

In their published study, they documented the complexity of predator-prey relationships they uncovered from this treasure trove of data.

A key illustration from the study draws lines showing predator-prey interactions between 20 different functional groups seen feeding on each other in the footage, from fish to crustaceans to jellies to cephalopods like squid. Fittingly, the resulting tangle of colorful who-eats-whom lines resembles a jellyfish.

“Jellyfish get kind of a bad rap,” Anela says, noting that some biologists cast them as nuisances—trophic dead ends that don’t feed back into the food web.

“This shows something totally different,” she says.” It shows they’re central parts of deep sea ecosystems, with really diverse diets and serving as both predators and prey.”

One species of jellyfish was observed eating 22 different kinds of prey.

(In the figure, many of predator-prey nodes loop back on themselves. “That,” says Anela, “is cannibalism—species within those broad animal groups feeding on one another.”)

There’s more to come

“Our method gives you a totally different view of the interactions going on in the food web,” Steve Haddock says.

The transparent bodies of animals like this medusa jelly let researchers peek into their guts and discover what they’ve been eating — in this case, a red mysid shrimp. Photo © MBARI

It’s a bit like going from a map with only train tracks to one that includes highways, he says: “You feel like things are connected in only a certain way, but suddenly you see these other connections. This study really complements and expands our view of what’s going on in the ocean.”

Still, Steve says there’s much left to learn.

“Even though this method has revealed a large diversity of interactions, there’s still a whole other universe of interactions we haven’t discovered,” he says.

The next layer of discovery may not come from video observations. Steve sees great promise in techniques like analyzing predators’ gut DNA for hints about their recent meals. Another avenue that is already widely utilized is compound-specific stable isotope analysis, which looks for chemical signatures that might accumulate in a creature’s tissue from eating certain prey.

Jellies often eat other jellies, as is the case with this red medusa preying on a siphonophore. Researchers documented some animals that fed on 20 or more prey species. Photo © MBARI

(That’s the approach used in a recent study by Aquarium researchers to document changes in North Pacific seabird diets over the past 130 years.)

“There will continue to be a lot more revelations about food web connections,” Steve says.

Anela agrees: “You hear that the deep sea is like outer space—it’s so poorly known and so poorly explored, every time we go down there we learn new things. All of that is true. But really, understanding that food webs tie everything in the ocean together is the reason I study them.”

Our ever-growing understanding of those connections, she says, will be critical to stewarding the ocean in the future.

—Daniel Potter

Choy, C.A., Haddock, S.H.D., Robison, B.H. (2017). Deep pelagic food web structure as revealed by in situ feeding observationsProceedings of the Royal Society B. 284: 20172116, doi: 

Marching ahead with ocean conservation science

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

Researchers discovered Pacific bluefin tuna can move their dorsal fins with an internal hydraulic mechanism that aids in fast swimming and quick turns

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

Sea turtles use their flippers in a multitude of ways to help them capture prey, like this green turtle in the Gulf of Thailand that’s grasping a jelly before it eats. Photo © Rich Carey/Shutterstock.com

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

Some of the feathers in the study were from seabirds collected in the 19th century by groups like this 1885 party that landed in the Northwest Hawaiian Islands. The specimens are archived at the Bishop Museum in Hawaii. Photo courtesy Bishop Museum.

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

White shark bites are causing the majority of sea otter deaths at the edges of the otters’ range. Photo courtesy MBAPhoto © Nicole LaRoche, U.S. Geological Survey

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

Juvenile white shark swims at the surface of Bahia Sebastian Vizcaino. Photo courtesy CICESE.

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.

—Athena Copenhaver

Learn how we use science to support ocean policy, address plastic pollution and climate change, protect marine wildlife and ecosystems, and promote sustainable global fisheries and aquaculture.

Flippers, not fingers: Sea turtles’ surprising feeding strategies

Imagine you’re trying to eat a snack—a tasty sustainable fish taco, let’s say. But there’s no plate, no cutlery, and you can’t use your hands. Also, gravity is muted, so the taco has a frustrating tendency to float away between bites.

Sea turtles use their flippers in a multitude of ways to help them capture prey, like this green sea turtle in the Gulf of Thailand that’s grasping a jelly before it eats. Photo ©Rich Carey/Shutterstock.com

If this sounds difficult, you’re beginning to understand the challenge of being a hungry sea turtle, stuck with awkward flippers more useful for moving around than for grasping prey.

Still, sea turtles make do with what they have. And, as it turns out, they can (and do) use their forelimbs to corral, swipe and hold food.

Their behavior is the subject of a new publication by Monterey Bay Aquarium researchers Jessica Fujii and Dr. Kyle Van Houtan. It’s something that’s been noted in passing in scientific literature, but Jessica and Kyle say it’s a fascinating glimpse into the evolution of ocean creatures. Read more…

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