Royal penguin colonies in the southern islands are under severe threat from climate change. Their population could decrease by more than 70% before the end of the century. Unless they adapt by migrating further south.
Things are heating up for the Royal Penguin. According to a study published in Nature Climate Change on February 26, 2018 led by researchers Céline Le Bohec and Robin Cristofari, of the Hubert Curien Multidisciplinary Institute and the Scientific Center of Monaco, more than 70% of the world’s population of royal penguins (or 1.1 million breeding pairs) could disappear before the end of the century.
The reason for the king’s decline is the climate upheaval that warms the oceans and displaces schools of fish. The largest colonies of royal penguins nest today on the sub-Antarctic islands of Crozet, Kerguelen and Marion / Prince Edward. These islands offer them both cool temperatures, ice-free waters and wide sandy or pebble beaches. This is where they lay their eggs and then raise their chicks for more than a year. Another great advantage of these southern islands is their proximity to the Antarctic Polar Front, an oceanic region where the cold Antarctic waters meet warmer waters of the sub-Antarctic regions: biologically very active, it concentrates enormous amounts of krill and fish; a real pantry for parents who find food in abundance to feed their offspring. In turn, they travel on average between 300 and 500 kilometers to reach this pool.
But the ongoing warming of the oceans is gradually pushing this front towards Antarctica. The penguin parents must then travel more and more distances to feed their chicks. The latter, who is waiting on the beach for the return of his parents, must fast more and longer. Soon, the absence of the parent left for food will exceed the fasting capacities of the chicks. Beyond ten days of absence, they will die. The populations will collapse and will disappear or to migrate further south, only possible adaptation in the short term.
Easier said than done, because the islands are not so numerous in the Southern Ocean and do not necessarily have the capacity to accommodate the huge current colonies. According to the researchers, the Bouvet Islands, Heard or South Georgia could be the most welcoming.
But the king penguin may have a hidden asset under its wing. The study of its genome has made it possible to reconstruct the demographic changes that have affected the species during the last fifty millennia. The researchers confronted them with past environmental changes that had already altered the ocean currents and affected the polar front. As a result, each of these upheavals – the last crisis took place 20,000 years ago – was catastrophic for king penguins. But they have each time survived! The genotype study of 163 individuals from 13 different locations has also shown that the different colonies of king penguins are very similar genetically: this is explained by a high migration rate between colonies. Marked individuals have been found at about 1400 km distance, which proves that dispersion is strong at the scale of a generation. King penguins are able to explore new habitats during their lifetime. In addition, new settlements have been established in recent decades, probably fueled by immigration.
Is it still possible? In the meantime humans have settled all over the planet, including in the most remote areas of Antarctica, reducing and splitting the habitats of wild animals, limiting access to feeding or nesting areas. Not to mention industrial fishing, including krill fishery by the Chinese and the Norwegians, which seriously affects the food chain of this fragile region. Competition for nesting and feeding sites may be difficult, especially with other penguin species. But for now, there is an urgent need for effective habitat conservation measures for this iconic species of Antarctica.