The waters surrounding the Antarctic Peninsula are warming rapidly, yet we know very little about how this is impacting some of the region’s most charismatic denizens: the filter-feeding baleen whales that call this icy realm home. But a team of scientists is hoping to change that with the help of their flippered subjects. They’re flying drones above whales and sticking cameras on their backs to capture a cetacean-eye-view of the world.
The work, which involves sneaking up on multi-ton marine mammals in an inflatable boat and prodding them (very gently) with a six-metre-long pole, requires a certain amount of mettle.
“These kinds of experiences always remind us that we are not dominant creatures,” Dave Cade, a postdoctoral researcher at Stanford University’s Hopkins Marine Station who has personally deployed nearly 200 video tags on whales, told Earther. “You’re almost putting your life in their [the whales’] hands.”
Cade, along with Stanford PhD student Shirel Kahane-Rapport, recently spent two and a half weeks in a sailboat traversing the western side of the Antarctic Peninsula with a documentary film crew. For several days, they had the opportunity to collect rare point-of-view footage from the backs of Antarctic humpback whales. This footage, captured with specialised tags that include an accelerometer and a camera, offers an intimate glimpse into the lives of whales in a part of the world that experiences little direct human disturbance, but which is ground zero for climate change on the southern continent. The Antarctic Peninsula has warmed dramatically over the last 70 years, causing regional sea ice to plummet and triggering ripple effects across the entire ecosystem, from ice-loving krill whose numbers tend to fall after winters with less sea ice, up to the whales that eat them.
“We’re basically asking the animals that are being screwed”” by vanishing sea ice and shifting prey patterns ” “to tell us how they’re being screwed,” Ari Friedlaender, a marine ecologist at the University of California, Santa Cruz who helps lead this work, told Earther.
Video tags are like universal translators that allow whales to show scientists exactly how they’re being sucker-punched by climate change. To equip a whale with one, a team of researchers will typically sneak up on the animal and affix the sensor to its back from the end of a long pole. This summer, Cade, Kahane-Rapport, and a driver would hop an inflatable Zodiac boat and creep up on humpbacks that were resting or moving slowly at the surface, often after a dive.
Cade, standing at the front of the boat, was in charge of getting the tag situated on the whale’s back with a suction cup while taking care not to whack his shipmates with the pole. Meanwhile, Kahane-Rapport would ready a crossbow and shoot a dart at the animal in order to collect a small biopsy of skin and blubber, which can be analysed to study the animal’s genetics, stress hormone levels, and even pollution exposure (Friedlaender said that the biopsy is so small most whales don’t even notice when one is being taken. If they do, he speculates it is “perhaps like a mosquito bite.”).
“So I sit behind Dave and try not to hit him in the back while he’s waving this pole around,” Kahane-Rapport explained.
If all goes well, the entire process takes just a few minutes. But when the whales or the weather doesn’t cooperate, it can be “a lot more work and effort,” Cade said. This summer, the team experienced quite a bit of snow, which slowed their boat down in addition to making everyone wet and cold much faster. And while the humpbacks the researchers were tagging are relatively slow-moving targets, in 2018 and 2019, Cade was working with Antarctic minke whales, which he described as “squirrely.”
“They’re very manoeuvrable, so they’re hard to work around,” he said.
Recovering tags to retrieve their data is another challenge entirely. Under ideal circumstances, a tag will pop off its whale after about a day and float to the surface. Its antenna will shoot up and transmit a signal back to a receiver on the ship, which the scientists use to find it. But even in summer, there can be sea ice in the coastal waters of the Antarctic Peninsula, and a tag that drifts beneath the ice can become trapped. Or, a spate of warm weather can cause ice to melt rapidly, blanketing the ocean’s surface in a layer of freshwater. This can cause the tags”which are designed to float at seawater densities”to become stranded at depth Cade says that only a handful”about one per cent”of the tags the team has deployed became permanently lost at sea.
Despite the myriad hurdles, working with Antarctic whales is immensely rewarding, in part because of their relatively naivete about humans. Minkes and humpbacks, Cade said, will sometimes get curious enough to come right up to a boat. Or they might refuse to leave their pole and crossbow-wielding interlopers alone.
On a snowy day in early March, the team tagged a female humpback in Wilhelmina Bay, a stunningly scenic bay dotted with icebergs and surrounded by glacial cliffs where whales often congregate to eat krill. As they were backing away, the whale started to follow them. For about 15 minutes, she swam under the boat and alongside it, doing balletic movements with her flippers and turning on her side to make eye contact.
“It was pretty mind blowing,” Kahane-Rapport said. “You felt extremely small”you’re smaller than her flipper. There were at least three moments where I was looking directly into her eyes. It was a lot.”
Experiences like this are the most cinematic part of a cetacean biologist’s work. But the data the whale tags capture is equally important. The footage researchers collected from the backs of 30 minke whales in 2018 and 2019 is revealing how these animals divide their time between sea ice and open water. Recently, a team led by UCSB grad student Jacob Linksy that included Cade and Freidlaender devised a method to use this footage to accurately quantify the amount of sea ice the whales are encountering, essentially turning the animals into mobile environmental research stations. Freidlaender is hoping these early results, which were recently submitted to a peer reviewed journal, open the door to more widespread minke whale tagging campaigns.
“In a very short period of time, we went from knowing zero about these animals to having a robust dataset where we can really define habits and behaviour in a way that’s going to give us a foundation we can add to,” he said.
Meanwhile, scientists are using the footage captured on humpback whales to explore one of the most spectacular marine mammal behaviours: bubble net hunting. This is a carefully-choreographed group hunt where one or more humpbacks dive underwater and blows a spiraling ring of bubbles to form a “net.” Others in the group corral prey into the net, and everyone gets a feast. Scientists began documenting the behaviour in groups of humpbacks off Cape Cod and Alaska decades ago, but they’ve only recently witnessed it in the Antarctic.
Freidlaender is hoping more up-close footage will shed light on how exactly bubble net hunting works down south, where whales tend to be corralling krill rather than fish. “Drones from above give us a perfect aerial view, and tag data shows us how the animals are manoeuvring and what the bubble nets look like,” he explained.
In total, Kahane-Rapport and Cade managed to tag 11 whales on their latest trip, recovering 10 of them. They would have done even more, but this year’s field work was cut short by a force even more powerful than Antarctic weather: a global pandemic.
On the sailboat, Cade said, communication with the outside world was limited to “basically one text message a day” via an Iridium satellite link. Still, while they were in the field in early March, the researchers started receiving a trickle of information about countries shutting their borders down as the novel coronavirus spread around the world. On March 16, they learned that all Antarctic tour boats departing from the Argentine city of Ushuaia were suspended, including the ship that was scheduled to retrieve them on the March 20.
That left the scientists with just one other obvious ride back: the R/V Gould, a research ship that supports scientists working at the National Science Foundation-run Palmer Station. It just so happened to be ferrying the station’s summer crew back to Chile the same day Cade and Kahane-Rapport learned their boat wasn’t coming. Just before their internet went out”something Cade said would happen frequently”he and Kahane-Rapport got word they’d be rendezvousing with the Gould in the Gerlache Strait”a channel separating the Palmer archipelago, where Palmer station is located, from the northwestern Antarctic Peninsula”around 2 a.m.
The two spent the rest of the day scrambling to pack up their gear and retrieving the last of their tags from the water in the middle of the night before their ride showed up.
“It was a bit nerve wracking,” Cade said. Happily, they managed to catch the Gould and fly home out of Punta Arenas, Chile several days later.
Freidlaender also had a taxing journey back to civilisation after a separate fieldwork excursion to the Antarctic Peninsula in March: The tour boat he was on was turned away from port in Chile and had to spend 10 extra days in a quarantine before it could dock in the Falkland Islands. But he managed to find a small silver lining in the ordeal, which he says left him better prepared for the new reality that awaited in California.
“Being on a ship in a confined space, and being used to that as a profession, I think that has helped make coming home and being confined to a smaller space a bit easier,” he said.