The Myth of Salmon Bears

Salmon bear 1 Don McVee 800x500

Story by Cheryl Lyn Dybas ( photos by Donald McVee & Ilya Raskin )

SPIRIT BEARS have one of the most distinctive and conspicuous ‘polymorphisms’ of any mammal.

THIS IS THE STORY OF A CREATURE ALMOST AS MYTHICAL AS SASQUATCH – an all-white bear called a spirit bear. Unlike Sasquatch, however, scientists have verified that spirit bears exist. In British Columbia’s remote Great Bear Rainforest, this rarer-than-rare bear appears, seemingly out of nowhere, in the coastal rainforest’s shadows. It’s also the story of the spirit bears’ kin -- black bears and brown bears – and how the three bears share salmon, their common prey, in a dusky, moss-covered realm.

Scientists know the spirit bear as Ursus americanus kermodei, the Kermode bear, named after biologist Frank Kermode. Kermode, a former director of the Royal British Columbia Museum in Victoria, was among the first to research the subspecies. The spirit bear is a colour morph of the black bear Ursus americanus. The trait is recessive; both parents must carry a copy of the mutated gene for their offspring to be white.

“Spirit bears have one of the most distinctive and conspicuous ‘polymorphisms’ of any mammal,” says ecologist Tom Reimchen of the University of Victoria. Reimchen has spent much of his life studying the bears. “The white morph,” he says, “comes from a mutation in the same gene associated with coat colour variation in other mammals.”

 

Remnant of the ice ages

Spirit bears are throwbacks to the last ice age, a time when being white likely conferred an advantage to animals living near ice-white glaciers. Some scientists think that black bears on what is now the B.C. coast might have become separated from mainland Canada by ice, then inbreeding in this “refuge” increased the mutation’s frequency. As glaciers melted in that long-ago time, the bears became stranded on newly formed islands.

Today, spirit bears live only in two of the most distant places on the planet: B.C.’s Princess Royal and Gribbell Islands, some 50 miles (80 km) north of Klemtu, British Columbia. Klemtu itself lies 330 miles (530 km) due north of the city of Vancouver. Gribbell Island has two major salmon streams; Princess Royal Island has 30.

These islands at the ends of the Earth are ruled by salmon and bears, or bears and salmon. The line where one begins and the other ends have flowed together, especially in late summer and early fall when salmon migrate upstream to spawn by the thousands -- and bears, including spirit bears, await their arrival. The white bears were likely never common, but now no more than a few hundred exist, according to conservation biologist Chris Darimont of the University of Victoria and the Raincoast Conservation Foundation. Darimont has studied the bears’ genetics through the ursids’ hair and scat. “We can estimate how many of the black individuals carry the white form of the coat-colour gene,” he says, “giving us insights into the natural processes and human pressures that maintain the white version or lead to its demise.” About one of every ten black bears in the region is a spirit bear, says Darimont. By “region,” he's referring to the Great Bear Rainforest.*

Bears are central to efforts to protect the GBR, a term coined by environmental organizations in the 1990s. The GBR was officially recognized by the Government of British Columbia in February, 2016, in an announcement that 85 per cent of the region’s old-growth forests would be off-limits to industrial logging. “It’s an incredibly special place for spirit and black bears, as well as brown bears and the many other species that depend on Pacific Coast salmon runs to survive,” says Darimont.

From late summer through autumn, spirit, black and brown bears frequent fast-running, boulder-lined coastal streams brimming with salmon, a staple food for the bears. In spring and early summer, they amble through lowland estuaries. There they feed on protein-packed sedges, and on barnacles, mussels and other invertebrates they wrest from rocks in the intertidal zone. “But they’re always waiting for the return of the salmon in fall,” says Reimchen.

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Photo Ilya Raskin

That return may depend in part on how British Columbia’s glaciers fare in a time of accelerating climate change. A new study suggests that 85 per cent of North America’s salmon watersheds have at least some glaciers left, but that 80 per cent of those glaciers will be lost by 2100. What that means for salmon, scientists say, as well as for bears, is complicated.

Glaciers have shaped past and present habitats for Pacific salmon. “Pacific salmon” is the collective term for five salmon species: chinook, also called king; coho; pink; sockeye; and chum. During the last glacial maximum, some 45 per cent of the current North American range of Pacific salmon was covered with ice. Now most salmon habitat is in watersheds where glaciers are retreating, according to lead study biologist Kara Pitman of Simon Fraser University in Burnaby, Canada.

Disappearing glaciers will leave some salmon ecosystems more vulnerable to heat and drought, Pitman reports. Salmon will likely be threatened by lower water flows and increasing water temperatures. Will bears be left high and dry?  “There will be winners and losers that vary by area and salmon species,” says Darimont, who was not involved in the study. “How this scales up to bears and other consumers of salmon is a little hard to predict.”

Adds Reimchen, who also was not involved in the study, “Does this mean that commercial fishing fleets would target more of the salmon that would have ended up in British Columbia ‘bear rivers’? Based on the history of commercial fishing on this coast and on global climate change, I would predict that things would get worse for bears.”

Matt Sloat, a fish ecologist and science director at the Wild Salmon Center, says that “this is a sober assessment of predicted changes to the salmon landscape. Change is inevitable. But it’s also the case that salmon can continue to thrive, especially if we give them room to move into new habitat.” The Wild Salmon Center works to conserve wild salmon rivers and ecosystems across the Pacific Rim from California to Alaska to Russia. Sloat participated in the study.

salmon bear Pink salmon2 600x Photo Ilya Raskin

Retreating ice will create thousands of miles of potential new salmon habitat, the researchers believe. They point to salmon species’ long history of evolution and adaptation; the fish have been around since the Miocene 23.0 to 5.3 million years ago, a period with warmer temperatures and higher sea levels.

“Salmon have been dealing with an evolving landscape for a long time,” Sloat says. “They’ve outlasted ice ages and floods and scores of natural disasters. But human-caused climate change is happening fast. We need to make sure that any productive new salmon habitat isn’t lost to short-sighted development.” That could pre-empt gains for salmon. Ice retreat could open new river valleys for salmon -- or new sites for resource extraction and development. These are choices managers will need to make, according to Pitman. “We recommend that they consider the future state of salmon and how habitat may change by integrating longer-term predictive modelling of glacier retreat, and keeping pace with how salmon populations are changing.”

With climate change and glacier melt, warming waters and salmon declines, what’s the likelihood of glimpsing a spirit bear? “The chance of seeing a white bear in the wild is almost non-existent,” says Reimchen. “If it happens, it’s a ‘once-in-a-lifetime.” Just after dawn on a British Columbia-cool August day, a group of biologists and naturalists mills around on the dock of the Spirit Bear Lodge in Klemtu. We’re waiting for the motor vessel KX Spirit. Spirit will soon ferry us to a place straight out of a fable.

Once aboard the KX Spirit, our motley crew presses forward. Spirit threads north through foggy, narrow straits. A point of land emerges from the mist, the tip of Princess Royal Island. Spirit’s captain, a member of Canada’s Kitasoo/Xai’xais First Nation who’s known simply as “Moose,” drops anchor off Princess Royal Island and lowers a zodiac over the side. Crewmembers Mercy Georgia Starr Mason, also a Kitasoo/Xia’xais member, and Elissa Crouse climb in, followed by everyone but Moose, who remains with the boat.

Mason and Crouse guide us to a shoreline where the boulders are taller than we are. An hour of rainforest bushwhacking later, we perch on wet, mossy logs halfway down a narrow path to a steep creek. The creek will soon be filled with pink salmon making their journey upstream to spawn. "Pinks" are manna for bears. Reimchen and others have found that white bears have an advantage over black bears in catching salmon – the salmon can’t see white fur as clearly as black fur. Because salmon are the major source of protein for bears, “greater capture success by white bears could facilitate their persistence,” says Reimchen. Whither go salmon, he believes, so go bears.

From our spot on the trail, we hear waves breaking on a beach. We’re a short distance from where the creek meets the sea. Within minutes, Mason slowly turns, then raises her finger to her lips in the universal sign of “quiet.” Rooted in place and with hearts pounding, we watch as a bear that’s almost as white as a polar bear makes its sure-footed way along a rocky ledge to the creek below. There it “snorkels” for salmon, dunking its head in the water and peering from left to right and back again in search of unwary pink salmon. Over an hour when time seems to stop, the spirit bear gives up on one spot and pads to another down the creek until it reaches the ocean. It’s a breathtakingly lucky day for us, but not for the bear. No pink salmon today.

How long will spirit bears survive? “Despite the risks of a small population size and the destabilizing effects of immigration [black bears that don’t carry the mutation making their way to the islands], the long persistence of the white bears is a good sign for the future,” says Reimchen. That said, bandits are arriving in town. Brown bears, which also feast on salmon, are making their way to Princess Royal Island and other places in the GBR where salmon runs are still relatively healthy. Declining salmon numbers along the mainland coast are the driving force. Once the heavier brown bears reach the GBR, they can easily out-compete spirit and black bears for piscine prey.

"That’s already happening fairly frequently," says Brian Collen, general manager of B.C.’s Knight Inlet Lodge. As the salmon swims, Knight Inlet is 205 miles south of Princess Royal Island. The inlet is a fjord bordered by narrow, steep cliffs created by a massive glacier. Knight Inlet is one of the longest fjords on the B.C. coast – it cuts inland some 78 miles from the sea -- and is fed by the Klinaklini River. The river ferries nutrient-rich meltwater from the Klinaklini Glacier to the inlet.

Knight Inlet is known for its abundant brown bears. Like their black and spirit bear cousins, the bears feed on salmon in fall and sedges in spring and summer. No spirit bears dwell in the inlet, but “salmon tussles” between its brown and black bears may foreshadow life for spirit bears on islands to the north. Indeed, "the presence of a grizzly [brown] bear on a salmon stream mostly eliminates use of salmon by black [including spirit] bears," state Reimchen and Darimont, along with Christina Service of the University of Victoria, in a recent paper in the Journal of Animal Ecology.

Next the researchers are investigating how habitat destruction and human presence near salmon streams may prevent bears, whether brown, black or spirit, from finding fish. In Knight Inlet, says Collen, "the number of brown bears in the last couple of seasons has been in line with what we’ve seen in the past. But low counts of pink salmon have brought challenges for the bears, especially for females with cubs. Pink salmon returns along the entire Pacific Coast have been down. The cause has yet to be determined.”

The Blob, a huge patch of warm ocean water that formed in the Gulf of Alaska in 2013 and spread along the Pacific Coast, may be to blame, says biologist Melanie Clapham of the University of Victoria. Clapham spends her summers conducting research on Knight Inlet's bear population. Waters are again cooling, but numbers of fish and other species have yet to recover.

"Pink salmon have been way down," Clapham says, "leaving the bears with less protein-rich food." In years with few pinks in the inlet, "we see increased cub mortality," she says. In 2017, for example, 10 cubs didn't make it, a major loss, Clapham laments. If the downward salmon trend reaches places like Princess Royal and Gribbell Islands, says Darimont, “that will limit spirit bears’ long-term prospects.”

The Great Bear Rainforest’s ursine residents are its ambassadors, he believes, animals that remind us of important links between forest and ocean, salmon and people, past and future. A century from now, Darimont asks, "will the bears still be here, or will they have vanished into the rainforest mist?"

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