AFP, published on Saturday, December 24, 2022 at 12:06 p.m
As every year in December, the Bay of Sailors on Possession Island in Crozet was packed as thousands of king penguins flock to this isolated area of French Southern and Antarctic Lands (TAAF) in the Indian Ocean to breed.
The species, recognizable by its white and black feathers with a tinge of yellow, is making a comeback. Between the late 19th century and the first half of the 20th century it was massacred by seal hunters.
King penguins have rebuilt their numbers but are now threatened by global warming.
“In the end,” when there were no more seals to hunt, “the sealers used them as fuel, burning them to melt the seal fat in the cauldrons, then they made penguin oil for a while.” But it wasn’t of good quality,” says Robin Cristofari, manchologist at the University of Turku (Finland).
“The species is not far from extinction yet,” the scientist continues while observing the colony at Mariners’ Bay.
The population recovered in the 20th century, “but it’s been about twenty years since the population reached a plateau”, notes Robin Cristofari, “after a first wall, the species encounters a second, more insidious one: global warming”.
The king penguin spends its life in the sea and only returns to land to lay eggs. It needs a dry location but a reasonable distance from the polar front, the area where the warm and cold waters of the Indian Ocean meet, where it feeds on plankton and fish.
– reproductive journey –
The polar front is 350 km south of the Crozet Archipelago in January, but in bad years when it is very hot it can be 750 km away, too far to feed and returning in time to feed the couple and the chicks to feed.
“Reproductive success depends on the distance to the polar front,” summarizes Robin Cristofari.
With global warming, the polar front is drifting south and eventually Crozet could become uninhabitable for king penguins, who will have to migrate to other islands further south.
Of more than a million pairs worldwide, 500,000 breed on the Crozet Islands and 300,000 on the Kerguelen Islands, 1,400 km to the east.
“We are not worried about the species, the population will not disappear in the next fifty years,” assures the researcher, but his way of life could be seriously disturbed.
A penguin that lives to be about 25 years old will not have their first chick until they are about 6 or 7 years old.
“Playful and curious,” describes Robin Cristofari, he amasses in vast colonies, the egg balanced on its feet, belly up, “surrounded by surly neighbors.”
– Changing custody –
Males and females share the work 50:50, passing each other the hatching egg, a dangerous moment because predators are on the alert.
In a classic cycle, males and females arrive at Crozet in early November, meet and mate.
The female lays and gives her egg to the male and goes to sea to feed.
During the fifty days of incubation, which is the chick’s first month, it is alternate care. Father and mother pass the egg or chick on for feeding at sea and can go without food for up to a month to tend to their egg.
Then the parents can leave their little one alone to feed.
The chicks are well fed until May, and then fast in the southern winter.
The parents come to feed them from time to time, but they will not feed them again until spring returns.
“The cycle is set in such a way that it is easiest for the chick to start eating independently, ideally in midsummer,” explains the scientist.
Twelve months after hatching, the young penguins leave the earth hungry.
This alternation of food intake and fasting is of particular interest to researchers.
“It’s a species that goes from acute obesity to extreme leanness several times a year,” notes Robin Cristofari, “it would be devastating to a human organism.”