IN AUGUST 2010, a bowhead whale from the Bering Sea swam into the North-West Passage. Having negotiated Alaska and picked its way through the maze of ice-ridden channels off the north coast of Canada, it made its way to Viscount Melville sound. There it met a second bowhead, which had entered the passage from Baffin bay, next to Greenland.
The two met because the passage, long blocked by ice, is opening as the climate warms. The anecdote, which came to light thanks to satellite transmitters on the whales, is part of increasing data showing how ocean life is being transformed by rising sea temperatures, with some bits of apparently good news to sweeten the pill.
The two bowheads were tagged by Mads Peter Heide-J酶rgensen of the in Nuuk and his colleagues. Bowheads entered the passage in 2002 and 2006, but this was the first time two were seen to cross paths ().
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Heide-J酶rgensen thinks whales have been sneaking through, undetected, since the ice began to retreat. The Greenland population, once decimated by whalers, has grown suspiciously fast since 2000, and Heide-J酶rgensen suspects the hand of immigration from Alaska. That鈥檚 perfectly possible, says of the University of Haifa in Israel. In May 2010, he spotted a Pacific grey whale in the Mediterranean Sea, which probably got there via the Arctic. Further evidence of links between Atlantic and Pacific ecosystems comes from in Nunavut, Canada, where . They do not normally venture so far west, but seems to be changing that.
It鈥檚 not just whales that are affected by warming seas (see map). at the University of Bristol, UK, looked at 25,612 trawls in fisheries around the UK and in the North Sea between 1980 and 2008. There waters have warmed by 0.05聽掳C a year since 1980.Populations grew for 27 of the 50 most common fish; nine declined and 14 held steady (). 鈥淚 had expected to see many struggling and maybe one or two doing well,鈥� he says
In his surveys, cold-adapted species like cod were all in decline, replaced by warm-adapted ones like red gurnard, which breed faster. Markets are catching on. 鈥淔ive years ago fishermen were selling red gurnard as bait to crab fishermen for 50 pence a fish,鈥� Simpson says. Now restaurants buy them for 拢5 a fish.
But the pill is bitter-sweet. An open North-West Passage may be good news for bowheads, which will have more places to feed, but many Inuit will struggle, since they rely on walruses that are running out of sea ice on which to breed. And although UK fish markets may be boosted, that鈥檚 no help to fishing communities in the tropics. If temperatures rise dramatically, many species there will either move out or die.
