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King penguins could be wiped out by climate change

Published on 12/02/2008

  February 12, 2008 - One of the emblems of the Antarctic, the kingpenguin, could be driven to extinction by climate change, a French studypublished on Monday warned.   In a long-term investigation on the penguins' main breeding grounds,investigators found that a tiny warming of the Southern Ocean by the El Ninoeffect caused a massive fall in the birds' ability to survive.   If predictions by UN scientists of ever-higher temperatures in comingdecades prove true, the species faces a major risk of being wiped out, theysay.   Second in size only to the emperor penguin, king penguins (Aptenodytespatagonicus) live on islands on the fringes of Antarctica in the southernIndian Ocean, with an estimated population of two million breeding pairs.   The species is unusual in that it takes a whole year for all the birds tocomplete their breeding cycle -- the ritual of courtship, egg laying,incubating and chick rearing.   This extreme length, spanning the Antarctic winter and summer, means thebirds are vulnerable to downturns in seasonal food resources for incubatingtheir eggs and nurturing their chicks.   Their main diet, small fish and squid, depends on krill. These minutecrustaceans are in turn extremely sensitive to temperature rise.   The team, led by Yvon Le Maho of France's National Centre for ScientificResearch (CNRS), marked 456 penguins with subcutaneous electronic tags at abig breeding ground on Possession Island on the Crozet archipelago in thesouthern.   They buried radio antennas on pathways used by the penguins on the islandand connected them to a computer that automatically recorded when the birdscame and went.   The surveillance programme ran from November 1997 to April 2006, a periodthat included an El Nino, the cyclical warming event that is not linked toclimate change.   During the El Nino, penguins that were early breeders did well, but thosethat bred later were badly hit, as the progressively warmer seas made foodrarer.   But the overall impact on population only became visible two years later,because of the penguins' long reproductive cycle.   An increase of just 0.25 degrees Celsius (0.45 degrees Fahrenheit) insurface sea temperature translated into a nine-percent decline in an adultbird's chance of survival, Le Maho calculates.   According to the UN's Nobel-winning panel of climate scientists, the meanglobal temperature is already set to rise by around 0.2 C (0.35 F) per decadeover the next two decades as part of a longer warming trend this century.   "Our findings suggest the king penguin populations are at heavy extinctionrisk under the current global warming predictions," the scientists say.   Their paper is published on Monday by the US journal, Proceedings of theNational Academy of Sciences (PNAS).