The Crozet islands is located halfway between the southern tip of Africa and Antarctica. One of the islands in the archipelago, named Île aux Cochons, is home to the largest colony of king penguins on earth. The king penguin is the second largest penguin species on earth after the emperor penguin. The last time scientists counted the population there was an estimated population of 2,000,000 of the 3 foot tall highly specialized birds. Reviewing satellite images and other photographic evidence, Antarctic scientists report that the colony has collapsed to a population of only 200,000. This is significant because the Île aux Cochons represents one third of the earth’s King Penguin population. These birds do not make a nest on the treeless island, instead they “lay one egg at a time and carry it around on their feet covered with a flap of abdominal skin, called a brood patch”.
The University of Vienna describes the conditions on which this particular penguin requires for survival. Hint, they are not flexible.
King penguins are in fact picky animals: in order to form a colony where they can mate, lay eggs and rear chicks over a year, they need tolerable temperature all year round, no winter sea ice around the island, and smooth beach of sand or pebbles. But, above all, they need an abundant and reliable source of food close by to feed their chicks. For millennia, this seabird has relied on the Antarctic Polar Front, an upwelling front in the Southern Ocean concentrating enormous amounts of fish on a relatively small area. Yet, due to climate change, this area is drifting south, away from the islands where most King penguins currently live. Parents are then forced to swim farther to find food, while their progeny is waiting, fasting longer and longer on the shore. This study predicts that, for most colonies, the length of the parents' trips to get food will soon exceed the resistance to starvation of their offspring, leading to massive King penguin crashes in population size, or, hopefully, relocation.
The Agence France-Presse reports on the shocking population decline (reprinted in full by The Guardian):
Climate change may play a role. In 1997, a particularly strong El Niño weather event warmed the southern Indian Ocean, temporarily pushing the fish and squid on which king penguins depend south, beyond their foraging range.
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“This resulted in population decline and poor breeding success for all the king penguin colonies in the region,” Weimerskirch said.
El Niño events are cyclical events that occur every two to seven years, but they can be amplified by global warming, which itself produces many of the same results, albeit on a longer timescale.
Indeed, Weimerskirch and colleagues showed in an earlier study that climate change, on its current trajectory, will probably make the Crozet islands – the archipelago that contains Île aux Cochons – unviable for king penguins by mid-century.
The report indicates that for this island’s penguin population, migration is not possible as there are no other islands that are suitable in the archipelago. The scientists note that climate change plays a role, particularly El Niño weather events that warm the southern oceans temporarily, by driving the king penguin's food source of fish and squid to migrate south, beyond the penguins “foraging range”.
The University of Vienna notes that penguins were able to survive changes in the climate before:
But there is a major difference this time: for the first time in the history of penguins, human activities are leading to rapid and/or irreversible changes in the Earth system, and remote areas are no exception. In addition to the strongest impact of climate change in Polar Regions, Southern Ocean is now subject to industrial fishing, and penguins may soon have a very hard time fighting for their food. "There are still some islands further south where King penguins may retreat", notes Céline Le Bohec (IPHC/CNRS/University of Strasbourg and CSM), leader of the programme 137 of the French Polar Institut Paul-Emile Victor within which the study was initiated, "but the competition for breeding sites and for food will be harsh, especially with the other penguin species like the Chinstrap, Gentoo or Adélie penguins, even without the fisheries. It is difficult to predict the outcome, but there will surely be losses on the way. If we want to save anything, proactive and efficient conservation efforts but, above all, coordinated global action against global warming should start now."
A huge colony of king penguins on the Île aux Cochons in 1982