Researchers say what was once the world’s second-largest colony of emperor penguins has “now all but disappeared” after changes in sea-ice conditions made their typical breeding grounds highly unstable.

A group of researchers from the British Antarctic Survey (BAS) published their findings in the Antarctic Science journal on Thursday. The team said in a statement that they studied “very high resolution satellite imagery to reveal the unusual findings.”

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According to their research, satellite imagery showed that the emperor penguin colony at Halley Bay in Antarctica had drastically decreased over the past three years on account of breeding failures caused by severe changes in local environmental conditions.

“For the last 60 years the sea-ice conditions in the Halley Bay site have been stable and reliable,” the team said. “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.”

The group said the conditions were repeated the following two years, leading to “the death of almost all the chicks at the site each season.”

“The colony at Halley Bay colony has now all but disappeared, whilst the nearby Dawson Lambton colony has markedly increased in size, indicating that many of the adult emperors have moved there, seeking better breeding grounds as environmental conditions have changed,” the researchers said.

Peter Fretwell, the lead author of the report and a remote sensing specialist at BAS, said the team has been studying the population of penguins at the Halley Bay colony and other nearby colonies for years using the high resolution satellite imagery.

“These images have clearly shown the catastrophic breeding failure at this site over the last three years,” Fretwell said. “Our specialized satellite image analysis can detect individuals and penguin huddles, so we can estimate the population based on the known density of the groups to give reliable estimate of colony size.”

Phil Trathan, a penguin expert with BAS who co-authored the report, 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," he said, adding that the penguins are likely to lose between 50 percent and 70 percent "of their numbers before the end of this century as sea-ice conditions change as a result of climate change.”

The researchers said they plan to continue to study the colony's response to the changing sea-ice conditions to help other scientists gain "vital information about how this iconic species might cope with future environmental change."