Antarctica: Rising sea ice 'hurts' elephant seal breeding

Elephant seals Image copyright Getty Images
Image caption Elephant seals on a beach in the US

Elephant seals living close to Antarctica might find it harder to breed in the face of rising sea ice, it seems.

"When there's more sea ice the population is likely to go down and in years when there's less sea ice the population is likely to go up," marine biologist John van den Hoff tells the Reuters news agency. Scientists say the number of breeding female elephant seals on Macquarie Island near Antarctica has dropped nearly 25% between 1988 and 2009.

Sea ice is also affected by the combination of colder winds and warming seas, van den Hoff says, because it drives up the readings of a key weather variability index called the Southern Annular Mode (SAM). Higher SAM readings appear to correlate with lower elephant seal birth rates.

Scientists suggest the changing weather patterns may be linked to a hole in the ozone layer and rising greenhouse gas emissions. But the trend may not be all bad news for elephant seals, as lower sea ice levels elsewhere around Antarctica might provide better breeding conditions for other elephant seal colonies.

"It is still too early to say whether elephant seals will be climate change winners or losers," van den Hoff says.

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