24 June 2012

Chinstraps disappear from Deception Island

ANTARCTICA – It appears that global warming has struck again, with new research finding that a colony of chinstrap penguins on Deception Island has declined more than one-third in the past 20 years.

The study by Andres Barbosa of the National Museum ofNatural Sciences in Madrid and his colleagues was published online in the journal Polar Biology.

The researchers carried out censuses of chinstrap penguin in the Vapour Col colony of Deception Island, one of the South Shetlands Islands, from 1991-92 and 2008-09. Nest counts were taken from photographs that were recorded from a standard location, mainly in December around the time of peak hatching. They found that the population had declined by 36% between 1991 and 2008. The strongest decline occurred since 2000.

After considering and ruling out research activity and tourism as the reason behind the chinstrap’s decline, the researchers point to global warming as the likely culprit because of its effect on the extent of Antarctic sea ice.

The chinstrap’s main prey is krill, which depend on the algae that grow under the sea ice. As rising temperatures cause the ice to melt, the krill population is declining, having a knock-on effect on the chinstrap population.

This idea is supported by the fact that the region’s krill-eating Adélie penguin population is also declining, but the population of gentoo penguins, which have a more variable diet, is not.

Barbosa told LiveScience that in the 1990s it was thought that climate change would favour the chinstrap penguin, which prefers ice-free waters, over the Adélie penguin, which prefer an icy environment.  At the time, chinstrap numbers seemed to be increasing. However, the decline in sea ice is now at the point it is impacting the abundance of krill, and consequently chinstrap penguin population.

"This is an example of how the human activity far from the poles can affect the life at thousands of kilometres far from our homes," Barbosa said.

He pointed out ways can help Antarctica's penguins. People need to use energy and fossil fuels responsibly to preserve the planet and, by extension, Antarctica, and also need to reduce overfishing, tourism and research activity in Antarctica to protect the organisms that live there.

Polar Biology citation
Population decline of chinstrap penguins (Pygoscelis antarctica) on Deception Island, South Shetlands, Antarctica. Barbosa, A., Benzal, J., De León, A. and Moreno, J. Polar Biology, 22 May 2012, DOI: 10.1007/s00300-012-1196-1

36% of chinstrap penguins missing from Antarctic Island by Jeanna Bryner, 19 June 2012, LiveScience

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