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Meltdown leaves walruses cold
17/04/2006 17:17 - (SA)
Washington - Arctic researchers have discovered a surprising number of abandoned baby walruses, and said melting sea ice might be the culprit.
During an icebreaker cruise in the Canada Basin two years ago, researchers measured an unusually warm mass of water - as high as seven degrees Celcius - moving into the area from the Bering Sea to the south.
In a study published in the April issue of Aquatic Mammals, researchers said this warm water may have rapidly melted seasonal sea ice over the shallow continental shelf north of Alaska.
They found nine possibly abandoned walrus calves in the area, an "unprecedented number" for walruses, said researchers, as mothers tend to stay with their calves for two years.
Carin Ashjian, a biologist at Woods Hole Oceanographic Institution said: "We were on a station for 24 hours, and the calves would be swimming around us, crying. We couldn't rescue them."
'Walruses cannot adapt'
Sea ice offers foraging walruses a place to rest.
Mothers leave their calves on the ice while they dive to feed on animals on the sea floor such as crabs and clams.
But researchers said the rising ocean temperatures may be forcing the walrus mothers to abandon their young as they follow the rapidly retreating ice edge north to colder waters.
They said that, without their mothers, the calves would likely drown or starve.
Ashjian said: "The young can't forage for themselves. They don't know how to eat."
Sightings of solo walrus calves far from shore have not been reported before.
Researchers said this suggested that increased polar warming would take a toll on the walrus population.
The researchers concluded: "If walruses and other ice-associated marine mammals cannot adapt to caring for their young in shallow waters, without sea ice available as a resting platform between dives to the sea floor, a significant population decline of this species could occur."
Funded by the National Science Foundation, the study investigated the impact of global climate change on the oceanic ecosystem over the continental shelf of Alaska.
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