In a horrific catastrophe, the world’s second-largest colony of emperor penguins is believed to have been utterly wiped out after an ice shelf in Antarctica collapsed, causing thousands of chicks to drown.
According to researchers from the British Antarctic Survey (BAS), the collapse of the ice sheet at Halley Bay in 2016 completely destroyed the colony, which has “now all but disappeared” due to changes in sea ice conditions.
Since then, breeding activities normally detected in the area have ground to a halt. The team of scientists relied on high-resolution satellite imagery to reveal the unusual findings, which were published Thursday in the Antarctic Science journal.
The bay, which lies in the Weddell Sea, was once considered a refuge for the emperor penguins in one of the continent’s coldest regions. Experts believed the area would have held stable for penguins throughout the century despite the widespread climate change devastating polar sea ice.
Around 15,000 to 24,000 breeding pairs usually flock to the site every year, comprising five to nine percent of the global emperor penguin population.
However, high-resolution satellite imagery of the penguins’ guano has shown that since the 2016 collapse, there have been three consecutive years of breeding failures.
In a statement, the researchers said:
“The failure to raise chicks for three consecutive years is associated with changes in the local sea-ice conditions. Emperor penguins need stable sea-ice on which to breed, and this icy platform must last from April when the birds arrive, until December when their chicks fledge.
For the last 60 years the sea-ice conditions in the Halley Bay site have been stable and reliable. But in 2016, after a period of abnormally stormy weather, the sea-ice broke up in October, well before any emperor chicks would have fledged.
This pattern was repeated in 2017 and again in 2018 and led to the death of almost all the chicks at the site each season.”
The colony at Halley Bay has now been all but completely wiped out, while the neighboring Dawson Labton colony has increased in size—a result of adult emperor penguins finding better breeding grounds there in lieu of the fast-changing environmental conditions.
Emperor penguins are among the largest penguin species, weighing in at up to 90 pounds and living for up to 20 years. They require a stable sea ice habitat from April to December in order to successfully breed and survive before moving to the open sea.
While global climate change would appear to be the most apparent culprit for the colony’s demise, researchers are circumspect about naming a precise cause beyond abnormal weather patterns.
However, the team remains certain is that the global emperor penguin population is facing grim times ahead as a result of fast-warming climatic conditions.
Penguin expert and report co-author Phil Trathan said:
“It is impossible to say whether the changes in sea-ice conditions at Halley Bay are specifically related to climate change, but such a complete failure to breed successfully is unprecedented at this site.
Even taking into account levels of ecological uncertainty, published models suggest that emperor penguins numbers are set to fall dramatically, losing 50-70 percent of their numbers before the end of this century as sea-ice conditions change as a result of climate change.”
The scientists added that will continue to study the penguins’ response to environmental changes in order to gain “vital information about how this iconic species might cope with future environmental change.”
According to a 2014 study by Stephanie Jenouvier, a penguin expert from Woods Hole Oceanographic Institute, the global population of emperor penguins is expected to decrease by around one-fifth by the turn of the century.