Bowhead homecoming
The longest-living mammals on Earth, bowhead whales have outlived the whalers that once hunted them to near extinction. Now, these gentle giants appear to be making a comeback in ice-covered waters.
Having all but vanished from Norway’s waters for 80 years, bowhead whales seem to be making a return
“The fog has lifted – flying conditions are perfect!” shouts Christian Lydersen, senior scientist at the Norwegian Polar Institute (NPI). By the time he has run up all 86 steps to join the rest of us atop the observation deck of the icebreaking polar research ship RV Kronprins Haakon, he is somewhat out of breath.
Minutes later, we are in a helicopter, taking in the mosaic of dazzling white ice floes and inky black waters of the Fram Strait, the deep passage of water that separates Greenland from Svalbard. It is June 2018, and we are in search of a giant.
The bowhead whale is one of the ocean’s most elusive creatures, living a hidden life deep under the sea-ice. Having all but disappeared from Norwegian waters for eight decades, this big, friendly giant seems to be making a gentle comeback. But why, and how? This we hope to find out by attempting something never done before: tagging a bowhead from the air.
The species hasn’t always been a rarity off Svalbard. In 1596, during an expedition to locate a trading route to China, thick ice conditions forced Dutch captain Willem Barentsz to change course. Steering south to open water, he discovered, at about 79° north, a land of “nothing more than mountains and pointed peaks.” This jagged panorama was the coast of Spitsbergen – the largest island of the archipelago we now know as Svalbard – and its waters were packed with whales, walruses and seals.
Word of these marine riches soon spread, and in 1611, the whalers started to arrive. First the Dutch, soon followed by the English; later the Basque, Danish and finally (in the early 1900s), the Norwegians. Whaling communities sprang up around Svalbard, their livelihoods dependent on hunting these leviathans in the fjords – not only bowheads, but also humpbacks and, in time, sperms, fins and blues. The cetaceans’ oil, procured by boiling blubber in enormous copper vats, was shipped to Europe to burn in lamps and lubricate machinery; their baleen was turned into clothing, tools and ornaments. Today, desolate rows of whalers’ graves and crumbling stone ovens are the only reminder of this prosperous period in Svalbard’s history.
Slowly turning the tide
Bowheads were the perfect quarry for whalers. One of four members of the right whale family (so called as they were the ‘right’ whales to hunt), they swim slowly, bear thick layers of blubber and float when
dead. Exactly how many were harvested during Svalbard’s 100-year bowhead whaling era is not known (scientists estimate that 25,000–100,000 bowheads were lost between 1611-1911), but by the close of the 1600s, the population had largely vanished.
The bowhead stock may have been depleted, but whaling techniques were becoming ever more sophisticated. Crews were setting their sights on other species, taking down the fastest fin whales by the mid-1800s. The modern whaling era in the north continued until the early 1900s, then moved to the Southern Ocean, where it continued in full force until the 1960s.
Between 1945 and 1980, just three bowhead sightings were recorded, with the population thought to have dwindled to fewer than 100 individuals. The whaling moratorium of 1982 had, it seemed, landed decades too late.
Nevertheless, the past 20 years have seen the cold wind of change blow through the Norwegian Arctic. In 2006, the NPI embarked on a bowhead survey, discovering a pod of at least seven animals. A few years later, the same scientists succeeded in tagging an individual – a first for the Svalbard-Franz Joseph Land population, and a milestone in the modern history of bowhead whales.
And the sightings have been racking up ever since. During a polar bear survey in 2015, aerial counts far inside the drift ice north of Svalbard discovered no fewer
than 27 bowheads. Meanwhile, tourist boats, both in the Fram Strait and around the archipelago, were also reporting new observations, as were other research vessels. Bowhead whales, it seemed, were once again blowing in the Svalbard seas.
As whales go, the bowhead is pretty impressive. It ‘only’ reaches a maximum length of 18m, but weighs nearly 100 tonnes (in the males, a single testicle weighs 1,000kg), a bulk surpassed only by blues and fins. It is able to smash through solid ice to make breathing holes, and hunting equipment recovered from inside one individual has led scientists to conclude that the species can live for more than 200 years. I may be in the chill of the Arctic, but nothing sends a shiver down my spine more than the thought that a bowhead alive today could have borne witness to the drama and commotion of the whaling heyday, fleeing harpoons on the high seas.
The chopper whirs monotonously as we cruise over the landscape, which from above
A bowhead alive today may have borne witness to the drama and commotion of the whaling heyday, fleeing harpoons on the high seas.
resembles a beautiful piece of abstract art. “There are many advantages to using a helicopter. Not only can we cover a bigger area in a shorter time, but we don’t disturb the whales as much as we would tracking them from a boat,” says Christian. “Besides, a bowhead will swim into dense sea-ice cover when scared, making it impossible to follow from the surface.”
Tagging a bowhead involves firing an arrow, equipped with the tracking device, into its blubber. “One of the main things we want to find out is how isolated the Svalbard–Franz Josef Land population is. Is the sudden increase in observations a result of migration into the area from other populations? Has the population increased, or have the whales always been there, but remained out of sight in the pack ice? There are many theories, but we need a better understanding of migration patterns and genetics to prove them,” says Christian.
“If we manage to tag a whale, we’d hope to follow that individual’s movements for a year
– but the transmitter will probably fall off long before that.”
Bowhead genetics can be studied via a skin biopsy – acquired by shooting a 5cm cylinder into the whale, which then pops out, complete with a small sample of skin and blubber. “Just one small sample can tell us not only about the relationship between the different subpopulations, but also about historical population sizes,” explains marine mammal scientist Kit Kovacs. “Satellite transmitters tell us about the present; genetic data tells us about the past.”
Track and trace
We have been airborne for an hour when Kit’s voice interrupts the din of the rotor blades: “Whale!”
The pilot instantly drops the helicopter from 100m to 15m. A large, dark shape is gliding steadily under the surface between the ice floes, its white-flecked tail leaving swirls of turbulent water in its wake. Its broad back looms large as it rises to take
a breath. A jet of water shoots into the air as the whale blows, and its fluke is thrown upwards. A split second before it disappears into the depths, Christian fires. “Hit!” he roars. With one small pull of a trigger, we have taken a giant step closer to explaining the reappearance of the species in Svalbard.
The bowhead may appear to be on the rise, but the alarm bells haven’t silenced yet. Olga Shpak is a scientist at the Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences in Moscow. She has studied bowheads in the Sea of Okhotsk, far East Russia, for many years. She has a unique opportunity to study how bowheads might cope with a warmer climate – as ‘her’ whales live in much warmer conditions already.
“Though the estimate of today’s SvalbardFranz Josef Land population is much higher than it was only a few years back, we know very little about the population trend for this area,” she says. “That numbers of observations are increasing might even be a bad sign for the population – less seaice might force the animals into more open water, making their calves more vulnerable to orca predation.”
Climate change has already decreased the average sea-ice thickness from 3m to 2m in the
Fram Strait during the past decade.
If the trend continues, it might mean more competition from seals and other whale species. “Warmer waters also may mean unexpected diseases – in the Sea of Okhotsk, whales have more parasites,” says Olga.
In other words, the bowhead whales in Svalbard are still in deep water. But for now, we need to keep learning all we can to try to protect them.
Less sea-ice might force the animals into more open water, making their calves more vulnerable.