GAME OF THRONES
As the climate in Canada’s Far North changes, polar bears are being affected. One impact — the increasing presence of killer whales in Arctic waters — may just unseat the King of the North.
ALONE POLAR BEAR ambles along the western shore of Hudson Bay, just outside the town of Churchill, Man. Every few minutes, she stops on the rocky beach, stands on her rear legs and peers across the bay’s open waters. Something out there has caught her attention. It’s late August. Months will pass before the increasingly unpredictable sea ice forms, providing a platform to hunt seals and fatten up after several lean months on land. It is not ice, however longingly anticipated, that has her scanning the cold, grey water. About 300 metres from shore, seven triangular dorsal fins betray the position of a group of unusual visitors to the bay: killer whales. Perhaps the polar bear is just as surprised to see the whales as the tourists whose Zodiac idles a stone’s throw from the pod. Certainly the boat’s driver with Sea North Tours — a lifelong Churchill resident — is astonished. “Oh man, I can’t believe I’m looking at orcas!” Remi Foubert-allen shouts over the noise of an outboard motor. “Look at the male’s dorsal fin. It must be seven feet!” His eyes widen as he gestures excitedly toward the pod. Foubert-allen knows something most people don’t: until recently, killer whales have been a rare sight in Hudson Bay. Jobie Attitaq, an Inuit hunter in Arctic Bay, Nunavut, has noticed the same thing on the northwest coast of Baffin Island. “In the late 1990s, we started to notice killer whales were coming around to Admiralty Inlet and even into Adam Sound and right here into Arctic Bay,” says Attitaq, chair of the hamlet’s Hunters and Trappers Organization. “We never experienced this before. Now we get them often.” In fact, killer whale sightings in Hudson Bay and the wider eastern Canadian Arctic have increased since the year 2000, leading Arctic scientists to muse about the rise of a new apex predator in the North. They say disappearing sea ice is opening up new hunting grounds for killer whales. At the same time, they say, it’s narrowing habitat for the North’s long-reigning monarch: the polar bear. Steve Ferguson, a biologist with Fisheries and Oceans Canada, is among those trying to figure out exactly why the whales are there and what their presence means for the Arctic ecosystem. He believes the whales are moving north as climate change opens up previously inaccessible hunting areas that are rich in belugas, bowheads, narwhals and seals. Ferguson’s research indicates that sea ice in Hudson Strait was once a choke point, preventing orcas from accessing Hudson Bay. Killer whales generally avoid ice because they can injure their tall dorsal fins as they swim underneath. But declines in the area covered by summer sea ice in the strait beginning in the 1960s are likely responsible for killer whales from the northwest Atlantic finding their way into the bay. Figures from the Canadian Ice Service support that conclusion. Researchers there say that since 1968, summer sea ice concentrations in Hudson Bay and in Hudson and Davis straits have declined by 15 to 20 per cent per decade. In Baffin Bay, they’ve dropped by 10 to 15 per cent per decade. Working with Ferguson, Winnipeg-based wildlife biologist Jeff Higdon has pored through old whaling logs and interviewed Inuit hunters to create a database of killer whale sightings in the region. He says European whalers kept detailed records starting in the 1600s, with no mention of these awesome predators in Hudson Bay until well into the 1900s. “The first record I know of for Hudson Bay was in the 1940s,” says Higdon. But sightings picked up starting in the late 1960s, with seven reported that decade. Records for the 1970s show 12. Ditto for the 1980s. Then a slight rise in the 1990s to 16 before sightings soared to 84 in the decade from 2000 to 2009. From 2010 to 2014, there were 24. Scientists with Fisheries and Oceans started paying closer attention in 2005, which probably boosted recent numbers, but a trend is clear. A similar pattern is evident in the wider eastern Canadian Arctic. Killer whales have been summertime visitors to Baffin Bay and Davis Strait since at least the late 1800s, but Inuit hunters say
they now see them more regularly and in larger numbers. This region has gone from 25 reported sightings in the 1960s to 79 in the decade from 2000 to 2009. From 2010 to 2014, there were 62. The fact killer whales are coming back year after year, and in greater numbers, tells Ferguson the hunting must be good. “They are doing well and reproducing,” he says, adding that he wouldn’t be surprised to see sightings continue to increase. Polar bears, on the other hand, appear to be facing a less promising future.
FOR SEVERAL HUNDRED
thousand years, polar bears have reigned supreme as the Arctic’s top predator. They are uniquely suited to a frigid world, expert in using sea ice as a platform for hunting ringed and bearded seals. But the Arctic is warming at twice the rate of lower latitudes, and their habitat is changing drastically. Polar bears have survived warming periods in the past — even to the point of crossbreeding with barren ground grizzlies whose territory overlaps theirs in the southern Arctic. Charlotte Lindqvist, an evolutionary biologist at the State University of New York, Buffalo, published a study in 2012 showing grizzlies and polar bears have swapped DNA over the course of five million years. Lindqvist suspects crossbreeding was more frequent during warmer periods as polar bear populations plummeted and grizzlies moved north. In fact, a handful of polar bear-grizzly hybrids have been confirmed in the Arctic over the last decade. But this time, even hybridizing is unlikely to have much of an impact on their survival, says Andrew Derocher, a polar bear researcher at the University of Alberta. Simply put, climate change is happening too fast for them to adapt, he says. “The concern over polar bears stems from the fact the worst is yet to come,” says Gregory Thiemann, a polar bear researcher at York University. “We haven’t seen catastrophic declines yet, but based on a clear understanding of the relationship between greenhouse gas emissions, sea ice and polar bears, this is coming.” Current estimates peg the global population of polar bears at between 20,000 and 25,000 — a relatively healthy number. But scientists generally agree the polar bear’s future is not bright. A U.S. Geological Survey study released in July confirms that the most significant threat is declining sea ice. It also predicts polar bear numbers will drop whether greenhouse gas emissions are reduced or not. While the study suggests the heavily iced Canadian Arctic Archipelago could be a last refuge, that’s only if global average temperatures increase by just 2 C. According to another study published in the November 2014 issue of the journal PLOS ONE, business-as-usual climate projections mean polar bears could face mass starvation and reproductive failure across the entire Arctic Archipelago by the year 2100. “If we can’t keep them in the Canadian High Arctic and northern Greenland, we are not going to have them in the wild,” says Derocher, one of the study’s co-authors. The issue is that polar bears are adapted to hunt seals from ice platforms: “I’ve seen them try for seals in open water,” he says. “I’ve never seen them succeed.” They can supplement their diet while on land during the summer with seabirds, eggs and the odd caribou carcass. And even when summertime pickings are slim, polar bears are able to tolerate long months without food. But here’s the crux: scientists believe the bear’s survival depends on its ability to feed on highcalorie seals when the ice returns. The PLOS ONE study suggests polar bears in the archipelago may have to survive serious increases in ice-free conditions by the end of 2100. While healthy adult males may make it through up to six months of fasting, juveniles, cubs and lactating females will struggle. Already, some populations are experiencing declining weight and increased mortality linked to disappearing sea ice.
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