Melting arctic ice lures killer whales further north

SKJERVOY-Agence France-Presse

In the pale winter darkness of northern Norway, a huge flock of seagulls circled above an arctic fjord, signifying the presence of an unusual predator group in the water below.

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As arctic sea ice shrinks to record levels due to global warming, killer whales are expanding their hunting grounds further north and spending more time in polar waters, according to US scientists.

But giant mammals, also known as orcas and which are at the top of the food chain, risk creating an “ecological imbalance” in the Arctic by attacking endangered species, a study warned. ‘University of Washington this month.

When AFP visited the vast Skjervoy Fjord in the Arctic Ocean, 70 to 80 killer whales could be seen congregating in family clans of around 10, including calves under one year old.

Increasingly frequent and northward sightings suggest that the iconic black and white member of the dolphin family, whose males can grow up to eight meters (26 feet) long and weigh six tons, is learning to s’ adapt to the newly melted waters of the Arctic Ocean.

“Thanks to acoustic surveys, we detected killer whales in the Barents Sea in November between Svalbard and Franz Josef’s Land, so they are clearly following the edge of the ice,” Marie-Anne Blanchet told AFP from the Norwegian Polar Institute.

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The killer whale, which with an estimated global population of 50,000 is found in almost every sea around the world, feeds on arctic prey such as the beluga and, most likely, some seal species, the specialist said.

The changing migratory patterns of whales are also linked to the fact that their favorite food, herring, is also moving further north, for reasons still unclear.

“They are predators with a great capacity to adapt, so they are opportunistic,” said Blanchet.

New hunting grounds also lead to unprecedented conflicts with humans.

In the waters off Greenland’s capital Nuuk, four orcas, seen as an unwelcome competitor by local fishermen and hunters, were killed in late November, an act permitted by Greenlandic law.

A University of Washington study presented in early December found that the increased migration of super predators is a consequence of the increasingly long season when the Arctic Ocean is free of ice.

“It’s not necessarily that killer whales haven’t been reported in these areas before, but that they appear to stay in the area for longer periods of time,” wrote co-author Brynn Kimber.

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The Arctic is warming three times faster than the rest of the planet, impacting the extent of sea ice and the ecosystems that depend on it.

The Arctic sea ice, which is also thinning, has shrunk by an average of more than 13% per decade over the past 40 years.

By the end of summer 2012, it had reached its lowest level on record, at 3.4 million square kilometers (1.4 million square miles), almost half its size in the 1980s. .

By analyzing eight years of acoustic readings, Kimber’s team also detected killer whales in the Chukchi Sea between

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Alaska and Russia during the months when it was frozen, as well as with greater frequency during the summer.

The study warned that the hunter, who also pursues prey in packs, is increasingly attacking the endangered bowhead whale, a species left exposed by receding pack ice.

These attacks are “likely to increase due to longer open water seasons,” the researchers said.


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