Thousands of emperor penguin chicks drowned after breeding ground was destroyed

The world's second largest colony of Emperor penguins has lost almost every chick for three years in a "catastrophic" breeding failure linked to melting sea ice. 

Antactica's Halley Bay usually attracts 14,000 – 25,000 breeding pairs, or up to nine percent of the world's entire population of Emperor penguins, each year. 

But since 2016 almost every chick hatched there has died before reaching fledgling age as ice melted early, a study of satellite images by the British Antarctic Survey has found.

"These images have clearly shown the catastrophic breeding failure at this site over the last three years," said Dr Peter Fretwell, who led the study, which was published yesterday/THURS. 

"Our specialised 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.”

Emperor penguins incubate, hatch, and raise their young on sea-ice during the Antarctic winter, making them vulnerable to climate change.  

For successful breeding, pairs need need a stable ice shelf to last from April, when they arrive and lay a single egg, until December, when chicks fledge and the penguins move to the open sea. 

In 2016 the ice sheet broke up in October, months before the chicks were ready to leave. There was no breeding at the site in 2017, and only a little in 2018.

The findings are alarming because ice conditions in Halley Bay were stable for at least 60 years and it was widely thought to be shielded from the affects of climate change.  

Some but not all, of the pairs appear to have relocated. The nearby Dawson Lambton breeding site, which previously hosted just a few thousand penguins, saw 11,117 pairs in 2017 and 14,612 pairs in 2018, the study said. 

Dr Phil Trathan, a penguin expert at the BAS and co-author of the study said it was impossible at this stage to specifically attribute the changes in ice in Halley Bay to climate change, but that the size of the breeding failure there was "unprecedented."

“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,” he said.