In-Depth

What a whale needs

Using cutting-edge technology, researchers are uncovering profound links among ocean health, climate change, and the denizens of the deep

What Whales Tell Us

Tag along with WWF scientists as they take CNN on an Antarctic whale expedition.

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On a frigid March day in 2023, Ari Friedlaender is bobbing in an inflatable Zodiac in Neko Harbor, slowly drifting toward a humpback whale. At the end of the 20-ft. pole he’s dangling over the side of the boat is a smartphone-sized device—a combination camera and satellite tag—outfitted with suction cups. Around him, the semi-frozen seascape brims with sound and activity—the rush of water, spouts of sea spray, and the noisy whoosh of blowholes in the icy air.

When the whale is close enough, Friedlaender lowers the carbon fiber pole and expertly attaches the noninvasive whale tag to the animal’s broad, slippery body. The humpback plunges beneath the waves, and the tag—which will fall off a day later—starts capturing underwater footage that will give researchers a glimpse into the whale’s a life as it dives, feeds, and socializes. It also tracks the marine mammal’s movements along the western coast of the Antarctic Peninsula—a 200,000-sq. mi. spine of mountain crests and glacial peaks jutting into the Southern Ocean.

“This technology is pretty amazing—we’re seeing from the whales’ perspective how they navigate and engage with their environment,” says Friedlaender. “We can look at how individuals move across the whole of their habitat.”

The research team works to attach a tag to a whale in the waters around the Antarctic Peninsula.

Over the past 25 years, the marine ecologist at the University of California, Santa Cruz has made more than 40 research trips to this world of sea ice and rich marine life. During that time, he’s gathered insights that are reshaping science’s understanding of the whales—humpback, blue, fin, and Antarctic minke—that migrate here each summer to consume Antarctic krill, the shrimplike superfood that’s particularly abundant during the season’s long, light-filled days.

Joining Friedlaender on this expedition is Natalia Botero-Acosta, the director of Macuáticos Colombia Foundation, who more often studies whales in the balmy Gulf of Tribugá along Colombia’s Pacific coast, and Chris Johnson, global lead for WWF’s Protecting Whales and Dolphins Initiative. The team—bundled in bright, thick jackets—is here to study where and how well the whales are feeding around the peninsula and hoping to identify their critical habitats.

OF THE 13 GREAT WHALE SPECIES, six are considered endangered or vulnerable—despite decades of protection following moratoriums on whaling.

Learning more about these ocean giants is urgent, as the cumulative impacts of industrial fishing, shipping traffic, pollution, and climate change pose increasing, often deadly threats in the whales’ foraging and breeding grounds—and on their long journeys between the two. To protect whales more effectively against those pressures, says Johnson, scientists must better understand the whale’s food web, distribution, movements, and which areas are most important to safeguard.

“When it comes to many whale species,” adds Friedlaender, “we still don’t even know where they give birth or how they find and follow their food.”

Antarctic sea ice—water that freezes, expands, and melts in the ocean—regulates the global climate, buttresses ice sheets, and circulates ocean water. It’s also the foundation of a complex food web. Phytoplankton—microscopic marine algae—bloom underneath the ice as sunlight filters through and feeds dense swarms of krill. Krill, in turn, are an essential food source for fish, penguins, seals, and baleen whales, which, depending on their size, can devour between one and 12 tons of krill per day.

Scientists have been monitoring the sea ice that encircles the continent for more than 40 years, using satellites to gauge its annual maximum and minimum extent. Typically, it’s at its largest in September and its smallest in March.

As sea ice disappears, researchers are studying whales’ foraging habits and identifying the migration routes and habitats that are critical to protect.

But as air and ocean temperatures spike, sea ice cover is hitting worrying new milestones. “This is the second year in a row where the winter sea ice in the peninsula was the lowest on record,” says Friedlaender, “which is the biggest red flag we could have.”

“Even simple actions, like shifting shipping lanes, restricting fishing when whales migrate through specific waters, or slowing boats down in blue corridors, could have immediate positive effects.”

Ari Friedlaender
Marine ecologist

The Antarctic Peninsula, part of the West Antarctic, is warming especially rapidly—at almost twice the rate of the rest of the world. Since the 1950s, its mean annual temperature has climbed by around 5°F, and its sea ice lasts 80 fewer days on average than it did four decades ago. This spring, after traveling far south, past the Antarctic Circle, the whale researchers find even less than they expected: It is sea ice-free.

While some whales, such as humpbacks, are faring well as melting sea ice opens more habitat for foraging, this short-term boon is deceptive. All species are “beginning to bump up against the ceiling that’s being lowered on them by climate change,” says Friedlaender. Krill are moving farther southward with the receding ice; for whales that migrate to feed on them, this shift makes a long journey even longer.

At the same time, less sea ice could lead to an upswing in large-scale fishery operations, which face pressure to increase their catch to meet growing demand for krill—an ingredient used in aquaculture feed, pet food, and health supplements. Under the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), which regulates fishing in the Southern Ocean, the Antarctic krill fishery catch skyrocketed to more than 450,000 tons in 2022. More and more, whales are directly competing with trawlers for food.

Drone footage offers an aerial view of two humpback whales.

As krill populations become locally depleted, explains Friedlaender, larger marine species will likely face increasing challenges. “Many whales have a binary lifestyle: They feed for a short period, migrate thousands of miles, then breed,” he says. “Female humpback whales need to get all the energy they can in a relatively short period while in Antarctica. From around December to April, if they can’t eat more than a ton of krill daily, it affects their breeding success.”

The team published a study in 2023 that found that it’s crucial for female humpbacks to get their fill of krill a year before they become pregnant so they can gain enough fat to support gestation. In 2017, following a year with plenty of krill, 86% of sampled humpback females were pregnant, compared to 29% in 2020, following a year with less krill.

To determine how well the whales are bulking up this year, the researchers used aerial photogrammetry—a technique that involves taking measurements from drone-captured photographs—to analyze the mammals’ body conditions.

“We saw an unusually high number of skinny whales late in the season,” Johnson says. “That’s a concern.”

Tools of the trade

DARTS

Researchers use hollow-tipped darts to obtain tiny samples of whale skin and blubber to biopsy. After a dart is shot from a low-powered crossbow, it bounces off the animal and floats in the water where it’s retrieved. To a whale, the dart feels equivalent to a mosquito bite, but the sample it yields can disclose lots of information. In addition to genetic connections, a sample can reveal a whale’s sex, reproductive health, level of accumulated toxins, and how it responds to stress.

DRONES

Using drones to get a bird’s-eye view of the whales allows researchers to identify individuals based on markings, estimate population sizes, assess their health, and spot evidence of entanglements and other scars or injuries. Drones can also capture certain whale behaviors, such as bubble-net feeding— whales working together to trap fish in spirals of bubbles from their blowholes.

TAGS

Satellite tags help scientists to collect video recordings and audio samples and enable 3D tracking of a whale’s movements through its habitat. The tags provide unmatched insights into whales’ feeding frequency and duration, diving depths, resting habits, social structures and communications—as well as environmental conditions such as sea ice cover, water temperature, and salinity.

Combined with information collected from video recordings, satellite tags, and biopsy sampling, that data helps researchers untangle the link between whales’ feeding behavior and health and associated factors, such as prey abundance, sea ice availability, and climate change—knowledge Friedlaender says is critical for pinpointing areas in need of greater protection. “We really need to understand the complete cycle of their ecology,” he says.

Until recently, little was known about whales’ movements between the endpoints of their journeys. In the past, notes Botero-Acosta, “we had to rely on the tiny percentage of time we had with whales at the ocean’s surface and extrapolate from that.”

But with GPS-capable tags, researchers can track the animals’ exact locations, mapping where they spend the most time and their migration routes. Tagging has revealed, for example, that starting around January, baleen whales in the Antarctic follow krill to feeding hotspots such as Gerlache and Bransfield Straits and the adjacent Wilhelmina and Flandres bays, which are also critical migration sites.

In 2022, WWF and a host of university partners—including Oregon State University, the University of California Santa Cruz, and the University of Southampton—published Protecting Blue Corridors, a groundbreaking report synthesizing satellite tracking data from over 1,000 tags collected by more than 50 research groups over 30 years. “With that data, we have a better picture of whales and their movement patterns, some of which are seasonal and some of which are year-round,” says Johnson. “When you plot those movements on a map, you uncover whales’ blue corridors—crisscrossing superhighways that sometimes span thousands of miles.”

Satellite tracking has shown that every fall, one population of Southern Hemisphere humpback whales journeys more than 5,000 miles between the west coast of South America—where females birth and nurse their young—and the Antarctic Peninsula. They swim along the Eastern Pacific Ocean corridor, one of the whale superhighways the report documents and a migratory hub also shared by a dozen species of great whales.

The report additionally highlights the multiple threats whales face as they navigate increasingly dangerous, loud, and polluted waters. While humpbacks have bounced back since commercial whaling was banned in 1982, they’re becoming more at risk of entanglement in fishing gear and collisions with ships along their migratory routes. They’re also affected by underwater noise due to increased shipping traffic. Other whale species, including the North Atlantic right whale, swim on the edge of extinction.

A whale underwater, passing in front of camera

A Bryde’s whale feeds on sardines near Baja California, Mexico, in the Eastern Pacific Ocean.

Scientists don’t know how or why whales choose their routes, but Protecting Blue Corridors makes the case for a new approach to safeguarding marine species. “This information collectively tells a story,” says Johnson. “By looking across the biological scale of whale habitats and migration, the report changes how we’re working together with partners, local communities, governments, and policymakers.”

He says conservationists hope to use the Global Ocean Treaty, a new UN pact to protect biodiversity on the high seas, to implement management tools and encourage more cooperation to address threats in national and international waters. “But because of the great distance and diversity of whale habitat,” he notes, “there’s no one-size-fits-all solution. In one area, it’s going to be ship traffic; in another area, oil and gas fields or underwater noise pollution; and in another, risks due to fishing gear.”

“If we want an animal to get safely from the Antarctic to Colombia, we must protect the waters in every country it passes,” says Friedlaender. “If we know where those animals are and at what time of year, we can be adaptive in their conservation.” Even simple actions, like shifting shipping lanes, restricting certain types of fishing gear when whales migrate through specific waters, or slowing boats down in blue corridors, could have immediate positive effects.

By 2030, WWF and its partners want to protect six blue corridors, including the Eastern Pacific superhighway. Promisingly, at the Ninth Summit of the Americas in June 2022, the governments of Canada, Chile, Colombia, Costa Rica, Ecuador, Mexico, Panama, Peru, and the US signed the Americas for the Protection of the Ocean declaration, committing to protecting 30% of their oceans in the Eastern Pacific—from Alaska to Patagonia—by 2030.

In addition, CCAMLR has plans to establish several marine protected areas around Antarctica that would protect around 1.5 million sq. mi. of critical ocean habitat—about the size of India. “We hope to get that over the line in the next two to three years,” says Johnson.

WHALES AND CLIMATE CHANGE

Scientists have realized that whales play a crucial role in regulating the global climate. In addition to capturing carbon throughout their lifetime—one whale can capture the same amount of carbon as thousands of trees—whale excrement fertilizes the ocean and boosts the growth of phytoplankton. These microscopic plants at the bottom of the marine food capture 40% of global carbon emissions and produce more than half of the world’s oxygen.

Eventually, conservationists hope to achieve a global network of connected, transboundary marine protected areas. And whales aren’t the only species that would benefit. Recent studies have revealed the vital role whales play in maintaining ocean health and in mitigating climate change. “Whales are so big and need so much food that if they’re around,” says Friedlaender, “that means the ocean is functioning to support them.”

Whale conservation was once about fighting whaling, but now, says Johnson, “we’re asking, ‘What can whales tell us about how to protect the ocean?’”

This shift toward seeing whales as an essential part of a functioning system is good for their conservation. “Now that we better understand how whales are connected to their ecosystems, we’re more connected to oceanographers and scientists studying carbon sequestration, carbon import and export, and nutrient flow,” says Friedlaender. “This is much more representative of the world whales live in.”

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