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Shrinking ice said to reopen major Arctic passage for whales

Sept. 24, 2011
Courtesy of the Royal Society
and World Science staff

Shrink­ing sea ice has al­lowed whales to nav­i­gate an Arc­tic route be­tween the At­lantic and Pa­cif­ic oceans for the first time in per­haps 10,000 years, sci­en­tists say. They pre­dict that the changes could let prev­iously se­par­ated an­i­mal popula­t­ions meet and in­ter­breed, por­tend­ing ec­o­log­i­cal shifts in the re­gion.

The sci­en­tists used sat­el­lite track­ing to determine that last year bow­head whales trav­eled in the North­west­ern Pas­sage, a fa­mously ice-bound wa­ter route through the Arc­tic Ar­chi­pel­a­go of north­ern Can­a­da and along Alaska’s north­ern coast.

Bowhead whales in the Western Arctic.


While the mam­mals did­n’t cross the whole pas­sage, whales from ei­ther side of it en­tered and reached the same, roughly hun­d­red-mile (160 km) wide ar­ea with­in it, a place called Vis­count Mel­ville Sound, sci­en­tists claim. That shows the chan­nel has be­come nav­i­ga­ble and the two popula­t­ions can meet, they con­tend.

Bones found on beaches in the re­gion sug­gest that the last time the whales oc­cu­pied this ar­ea was around 10,000 years ago, ac­cord­ing to re­search­ers, Mads Pe­ter Heide-Jør­gen­sen of the Green­land In­sti­tute of Nat­u­ral Re­sources in Nuuk, Green­land, and col­leagues. Bow­heads are ad­ept at mov­ing through ice-bound Arc­tic seas, but it was pre­vi­ously thought that the sea ice in the maze-like North­west Pas­sage was too thick for these stocky mam­mals, which grow to be about 50-60 feet (15-18.5 m) long.

“This route is al­ready con­nect­ing whales from two popula­t­ions that have been as­sumed to be sep­a­rat­ed,” wrote Heide-Jør­gen­sen and col­leagues, re­port­ing the find­ings in the Sept. 21 ad­vance on­line is­sue of the re­search jour­nal Bi­ol­o­gy Let­ters. The find­ings “are per­haps an early sign that oth­er ma­rine or­gan­isms have be­gun ex­changes be­tween the Pa­cif­ic and the At­lantic Oceans across the Arc­tic,” they added. “Some of these ex­changes may be harder to de­tect than bow­head whales, but the ec­o­log­i­cal im­pacts could be more sig­nif­i­cant.”

A route such as the North­west Pas­sage was sought by hu­man nav­i­ga­tors since the 1500s, but the chan­nel’s ex­ist­ence was prov­en only in the early 1800s. The Nor­we­gian ex­plor­er Ro­ald Amund­sen led the first ex­pe­di­tion across it in 1903 to 1906. An ice-breaking tank­er, the Man­hat­tan, be­came the first com­mer­cial ship to cross the pas­sage in 1969.


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Shrinking Arctic sea ice has allowed whales to navigate an Arctic route between the Atlantic and Pacific oceans for the first time in perhaps 10,000 years, scientists say. They predict that the changes could allow animal populations to come into contact and interbreed, portending ecological shifts in the region. The scientists used satellite tracking to find that in 2010 bowhead whales traveled in the Northwestern Passage, a famously ice-bound water route through the Arctic Archipelago of northern Canada and along Alaska’s northern coast. While the mammals didn’t cross the whole passage, whales from either side of it entered and reached the same, roughly hundred-mile (160 km) wide area within it, a place called Viscount Melville Sound, scientists claim. That shows the channel has become navigable and the two populations can meet, they contend. Bones found on beaches in the region suggest that the last time the whales occupied this area was around 10,000 years ago, according to researchers, Mads Peter Heide-Jørgensen of the Greenland Institute of Natural Resources in Nuuk, Greenland, and colleagues. Bowheads are adept at moving through ice-bound Arctic seas, but it was previously thought that the sea ice in the maze-like Northwest Passage was too thick for these stocky mammals, which grow to be about 50-60 feet (15-18.5 m) long. “This route is already connecting whales from two populations that have been assumed to be separated,” wrote Heide-Jørgensen and colleagues, reporting the findings in the Sept. 21 advance online issue of the research journal Biology Letters. The findings “are perhaps an early sign that other marine organisms have begun exchanges between the Pacific and the Atlantic Oceans across the Arctic,” they added. “Some of these exchanges may be harder to detect than bowhead whales, but the ecological impacts could be more significant.” A route linking the Atlantic and Pacific such as the Northwest Passage was sought by human navigators since the 1500s, but the channel’s existence was proven only in the early 1800s. The Norwegian explorer Roald Amundsen led the first expedition across it in 1903 to 1906. An ice-breaking tanker, the Manhattan, became the first commercial ship to cross the passage in 1969.