canary in the coal mine: drowned polar bears

Click for larger. The Beaufort Force is measured by
the visible white froth of violent waves. Mariners can
find safe harbor; polar bears must swim through seas
of all Beaufort Forces.

Sincerely miserable.

Clearly The Sunday Times of London has been reading Vleeptron, clicked on this morning's post (a filch from Reuters) about polar bears, then clicked on our link to the report on the increasing drownings of polar bears by scientists for the U.S. Minerals Management Service. (Or maybe The Times reporter went to the San Diego, California conference on marine mammals last week.)

Maybe the Kyoto Protocol is boring us and boring the Clinton and the Bush administration, but it's not boring Arctic biologists. For Global Warming, it seems very much as if Polar Bears are The Canary In The Coal Mine.

Inuits who accompanied some of the first successful Euro (Americans and Scandinavians) expeditions to the North Pole were very reluctant to leave solid land -- places like Baffin Island -- and venture off into the floating polar sea ice. Which is necessary, because the North Pole (unlike the South Pole) isn't on solid land, but rather in middle of an ocean full of floating ice. I think I read anecdotes that even the sled dogs knew when they were leaving snow-covered solid land for the ice shelf, and they didn't like it.

But the ice shelf and the floating ice islands are the hunting habitat of the polar bear; that's where the fat-rich seals are. When the adolescent males gather each October/November on the solid land around Churchill Manitoba Canada, they're just waiting for Hudson Bay to freeze and grow its winter ice shelf so they can go hunting seals.

Ironically, the report of the drowned polar bears comes from research conducted in the Beaufort Sea. The Beaufort Sea is an ocean region off the North Slope of Alaska and the adjacent Arctic Ocean coasts of Canada's Yukon and Northwest Territories. But Admiral Sir Francis Beaufort also invented the Beaufort Scale, which measures wind conditions on land or at sea. (He began his 68-year Royal Navy career as a cabin boy.)

If the maritime weather report predicts a Beaufort 10, 11 or 12, stay home, and keep your boat home, too.

But polar bears can't stay home -- or rather, their home is precarious ice shelves, islands and icebergs, and a lot of their hunting and roaming forces them to swim. I said they were remarkable swimmers, and they are. But when seas get monstrously rough -- Beaufort 10, 11 or 12 -- they drown before they can reach the next solid piece of ice which, as the ice melts, is farther and farther away.

Though common to adjacent Labrador, polar bears are not natural to the Canadian island of Newfoundland. But the park ranger at the only verified Viking settlement in the New World, l'Anse aux Meadows, told us that one morning he was awakened in his house trailer by a World's Largest Land Carnivore trying to open the metal container (the trailer) inside which he smelled possible food (the ranger). The ranger explained that Labrador bears sometimes wander onto a large drifting iceberg that bangs up against some part of the Newfoundland coast a couple of weeks later, and then the bear wanders onto Newfoundland to see if there's anything or anyone good to eat. If everybody gets lucky, they dart the bear and give it a free boat or plane trip back to the Labrador ice shelf.

Anyway, this really sucks. And after we finish weeping over the extinction of the Polar Bear ... guess which mammal comes next as the polar ice caps and the glaciers melt?

***********

The Sunday Times (London UK)
Sunday 18 December 2005

Polar bears drown
as ice shelf melts

by Will Iredale

SCIENTISTS have for the first time found evidence that polar bears are drowning because climate change is melting the Arctic ice shelf.

The researchers were startled to find bears having to swim up to 60 miles across open sea to find food. They are being forced into the long voyages because the ice floes from which they feed are melting, becoming smaller and drifting farther apart.

Although polar bears are strong swimmers, they are adapted for swimming close to the shore. Their sea journeys leave them them vulnerable to exhaustion, hypothermia or being swamped by waves.

According to the new research, four bear carcases were found floating in one month in a single patch of sea off the north coast of Alaska, where average summer temperatures have increased by 2-3C degrees since 1950s.

The scientists believe such drownings are becoming widespread across the Arctic, an inevitable consequence of the doubling in the past 20 years of the proportion of polar bears having to swim in open seas.

"Mortalities due to offshore swimming may be a relatively important and unaccounted source of natural mortality given the energetic demands placed on individual bears engaged in long-distance swimming," says the research led by Dr Charles Monnett, marine ecologist at the American government’s Minerals Management Service. "Drowning-related deaths of polar bears may increase in the future if the observed trend of regression of pack ice continues."

The research, presented to a conference on marine mammals in San Diego, California, last week, comes amid evidence of a decline in numbers of the 22,000 polar bears that live in about 20 sites across the Arctic circle.

In Hudson Bay, Canada, the site of the most southerly polar bears, a study by the US Geological Survey (USGS) and the Canadian Wildlife Service to be published next year will show the population fell 22% from 1,194 in 1987 to 935 last year.

New evidence from field researchers working for the World Wildlife Fund in Yakutia, on the northeast coast of Russia, has also shown the region’s first evidence of cannibalism among bears competing for food supplies.

Polar bears live on ice all year round and use it as a platform from which to hunt food and rear their young. They hunt near the edge, where the ice is thinnest, catching seals when they make holes in the ice to breath. They typically eat one seal every four or five days and a single bear can consume 100 pounds [45.5 kilograms] of blubber at one sitting.

As the ice pack retreats north in the summer between June and October, the bears must travel between ice floes to continue hunting in areas such as the shallow water of the continental shelf off the Alaskan coast -- one of the most food-rich areas in the Arctic.

However, last summer the ice cap receded about 200 miles further north than the average of two decades ago, forcing the bears to undertake far longer voyages between floes.

"We know short swims up to 15 miles are no problem, and we know that one or two may have swum up to 100 miles. But that is the extent of their ability, and if they are trying to make such a long swim and they encounter rough seas they could get into trouble," said Steven Amstrup, a research wildlife biologist with the USGS.

The new study, carried out in part of the Beaufort Sea, shows that between 1986 and 2005 just 4% of the bears spotted off the north coast of Alaska were swimming in open waters. Not a single drowning had been documented in the area.

However, last September, when the ice cap had retreated a record 160 miles north of Alaska, 51 bears were spotted, of which 20% were seen in the open sea, swimming as far as 60 miles off shore.

The researchers returned to the vicinity a few days later after a fierce storm and found four dead bears floating in the water. "We estimate that of the order of 40 bears may have been swimming and that many of those probably drowned as a result of rough seas caused by high winds," said the report.

In their search for food, polar bears are also having to roam further south, rummaging in the dustbins of Canadian homes. Sir Ranulph Fiennes, the explorer who has been to the North Pole seven times, said he had noticed a deterioration in the bears’ ice habitat since his first expedition in 1975.

"Each year there was more water than the time before," he said. "We used amphibious sledges for the first time in 1986."

His last expedition was in 2002, when he fell through the ice and lost some of his fingers to frostbite.

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