King Penguins in the Southern Ocean: The largest colony shrinks dramatically

While there were still about 500,000 pairs of penguins on an island in the Southern Ocean in the 1980s, there are now only 60,000 pairs left. The largest colony of king penguins has declined by just over 85% in the last 30 years, reports an international research team in the journal "Antarctic Science". The reasons for the decline are not clear.

King penguins (Aptenodytes patagonicus) breed in sub-Antarctic islands. On the island of Crozet, the Isle of Pigs, scientists discovered in 1962 a colony of about 300,000 breeding pairs. In the 1980s, satellite imagery suggested that about 500,000 pairs of penguins lived there. The breeding colony was considered the largest of the king penguins and the second largest colony of penguins in the world.

Researchers led by Henri Weimerskirch of the University of La Rochelle in France studied the development of the colony using aerial and aerial photographs taken between 1988 and 2017. "When king penguins were found # 39; install on the ground, the vegetation disappears, but the vegetation is preserved around the colony, so it's easy enough to see how much space the colony occupies, "said the Weimerskirch.

"Massive and Unexpected"

The researchers found that the colony has shrunk "massively and unexpectedly" by 85 percent over the past 30 years. "The penguins of all the archipelago have had great difficulty feeding, which has caused a general decline, while the other colonies of king penguins have since recovered, the island of pigs has become more in weaker. "

the warming of the seas threatens the royal penguins. The change is happening too fast. The fish and octopus are therefore retreating to Antarctica due to the warming of the oceans. In addition, industrial fisheries in the Southern Ocean deprive the food supply. Foraging for penguins can therefore take so long in the foreseeable future that offspring will starve

In their study, researchers investigated several possible reasons for the decline – introduced mice and cats eating chicks. Diseases with changing environmental conditions in relation to the El Niño climate phenomenon. "All these assumptions are insufficient to explain why there is a decrease in this size," said Weimerskirch at "Le Figaro". The researchers now want to study on the spot how it could come to dramatic decline.