One of the world’s largest emperor penguin colonies has suffered a “catastrophic” breeding failure.
Researchers from the British Antarctic Survey said the colony at Halley Bay in Antarctica’s Weddell Sea has failed to raise chicks for the last three years.
The colony used to be the second largest in the worlds – with between 14,000 – 25,000 breeding couples arriving every year.
The colony accounted for around 5% - 9% of the global emperor population.
BAS researchers said they discovered the breeding failure by studying high resolution satellite imagery in the area.
File photo of Emperor Penguins in Antarctica, 01-06-2009. Image: Vnoucek, F./DPA/PA ImagesSea-ice
The breeding failure is the result of changes in the local sea-ice conditions.
Emperor penguins need stable sea-ice to breed. The ice platform must last from when they arrive in April until December when their chicks have fully matured.
Scientists say the conditions remained stable and reliable for nearly 60 years.
For the last three years however, “abnormally stormy” weather conditions have seen the ice break up in October – far too early for the fledgling chicks.
The conditions led to the death of almost all the chicks at the site each season.
Climate change
Dr Phil Trathan, BAS penguin expert and co-author of the study said that while it is impossible to directly relate the failure to climate change, “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% of their numbers before the end of this century as sea-ice conditions change as a result of climate change,” he said.
The satellite images suggest the Halley Bay colony has now all but disappeared; however, the researchers believe many of the adults have joined the nearby Dawson Lambton colony, which has “markedly increased in size.”
Satellite imagery showing the reduction in size of the Halley Bay colony in 2018 compared with 2015. The dark markings show penguin guano, and the very dense patches are the penguins themselves. Image: British Antarctic SurveyEmperor penguin
Dr Peter Fretwell, the lead author of the study and BAS remote sensing specialist said the relocation of many of the birds to a more stable breeding ground is encouraging as, until now, it was unclear whether penguins would respond to environmental adversity by changing location.
“We have been tracking the population of this, and other colonies in the region, for the last decade using very high resolution satellite imagery,” he said.
“These images have clearly shown the catastrophic breeding failure at this site over the last three years.”
The study was published today in Antarctic Science.
