World’s largest king penguin colony declines nearly 90 per cent

The world’s biggest colony of king penguins in the National Nature Reserve of the French Southern and Antarctic Lands has shrunk by 88 per cent, according to new research. The cause may be environmental.

A reduction of 88 per cent in the size of the world’s largest king penguin colony has been detected using high-resolution satellite images.

The colony on Île aux Cochons in the Îles Crozet archipelago included 500,000 breeding pairs and over two million penguins when it was last visited by scientists in 1982, but has now yielded territory to vegetation.

While the causes of the colony’s collapse remain a mystery, they may be environmental, according to a statement about the new research, which was conducted by the Chizé Centre for Biological Studies.

Known since the 1960s, the colony of king penguins (Aptenodytes patagonicus) is isolated and inaccessible, meaning no new estimates of its size were made over the past decades.

The Chizé team used high-resolution satellite images to measure changes in the size of the colony. Photographs taken from a helicopter during the Antarctic Circumpolar Expedition confirmed that the colony’s penguin population has plummeted.

Data show that the decline began in the late 1990s, coinciding with a major climatic event in the Southern Ocean related to El Niño. This event temporarily affected the foraging capacities of another colony 100 kilometres from Île aux Cochons, explained the statement. The same process may be responsible for the fate of the Île aux Cochons colony.

Its size may also be subject to the fact that the larger the population, the fiercer the competition between individuals, which slows the growth of all members. Disease is another hypothesis entertained, with Avian cholera currently ravaging populations of seabirds on other islands in the Indian Ocean.

However, the researchers do not believe these possibilities offer a satisfactory explanation for a decline of the magnitude observed on Île aux Cochons. Field studies are scheduled to verify initial conclusions drawn from the satellite images.

Photo credit: Antarctican Khwairakpam Gajananda/ CC BY-NC 2.0

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