With its spiralled horn and elusive ways, the narwhal is a thing of legend. Isabelle Groc joins an expedition braving Arctic waters to meet it face to tusk
EVEN in the middle of August, Tremblay Sound in the Canadian Arctic is an inhospitable place. As the small plane descends, I get my first glimpse of our destination. Remote and desolate, it consists mostly of piles of rocks and a little scrubby vegetation. During my two-week stay it will be cold, wet and windy almost all the time. Nobody comes to Baffin Island to get a tan.
Nevertheless, this is the third summer running that Jack Orr from Fisheries and Oceans Canada has visited and, together with a team of scientists, vets and Inuit hunters, he seems right at home. In no time at all they have transformed the site into a fully operational research station, complete with colourful sleeping tents, a kitchen tent and a science lab housed in a plywood shack. Finally, they set their trap. Having firmly anchored one end of a heavy-duty fishing net to the shore, Orr jumps in a boat and crosses the narrow inlet so he can sink the other end to the seabed with a bag of rocks. Six buoys keep the upper edge of the net afloat to create a hanging curtain. All we can do now is await our quarry. Its scientific name is Monodon monoceros, which derives from the Greek for "one tooth, one horn" in reference to the males' spiralled tusk, which can extend up to 3 metres. Many people simply know these creatures as sea unicorns.
There are some 90,000 narwhals in the frozen northern seas. A small population lives off the coast of Svalbard, Norway, but most inhabit seas around Greenland, or are found in the northern reaches of Hudson Bay and in the Canadian high Arctic. The Baffin Bay population is one of the largest. Each summer, hundreds of narwhals return to these fjords and inlets. Orr and his team aim to catch nine of them as they swim past, and fit them with satellite transmitter tags.
Orr is a veteran of this research, having tagged 300 whales over the past 30 years, mostly narwhals and belugas. It is hard, unpredictable, time-consuming work, but it is worth the effort to better understand this elusive animal. Narwhals are particularly tricky to study because they spend each winter in the dense Arctic pack ice, in complete darkness. Satellite tracking is invaluable in efforts to learn more about them.
Another researcher, Mads Peter Heide-Jørgensen from the Greenland Institute of Natural Resources has been studying narwhals for two decades. Using satellite tracking he has found that they have strict migratory patterns. Year after year, each group undertakes the same migration in the spring and the autumn, moving between its winter feeding areas in the pack ice and coastal summering grounds (see map). The animals Orr studies leave northern Baffin Island in the autumn, migrating south to the Davis Strait where they spend the winter feeding on Greenland halibut, before returning the following summer. "They will go to the same places where they always go because they are programmed to do so," says Heide-Jørgensen.
Narwhals are experts at navigating and surviving in the extreme Arctic environment. In the winter, they traverse the pack ice following small cracks and leads. "I am mesmerised when I see how fast the ice changes," says Kristin Laidre at the University of Washington, Seattle. "In just an hour, a lead can close or completely freeze but the whales somehow know. They detect the change, and they are very good at navigating these dynamic areas." It turns out they are also one of the deepest diving whale species, with a record dive depth of 1800 metres, which may help them stay out of trouble.
Even so, a sudden freeze can catch them out. Between 2008 and 2010, there were several reports of narwhals becoming trapped in sea ice in Baffin Bay,unable to surface to breathe. At first, scientists thought changing sea ice conditions might be to blame, but then they discovered that the incidents coincided with seismic surveys of the bay. Narwhals are highly sensitive to noise; hunters in Greenland have known this for centuries and approach them in kayaks because if they use boats with noisy outboard engines the whales disappear. Heide-Jørgensen believes that the airgun noises from the survey may have interrupted the narwhals' migration, causing them to return to their summering grounds where they became trapped in the fast-freezing ice that now covered the sea surface. He and Laidre are currently using acoustic recordings and heart-rate monitors to better understand how narwhals perceive sound and react to noise produced by human activities.
Baffin Island in August never gets dark. We work 24 hours a day in 3-hour shifts to watch the net and keep a look out for polar bears. Often hundreds of narwhals swim past, yet none are caught. Waiting for a whale to hit the net is our main activity: when one becomes entangled it is crucial that we act quickly so that it doesn't drown. Bundled up against the cold, we watch and we wait.
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