Thousands of baby penguins wiped out as Antarctic ice shelf collapses

  29 April 2019    Read: 1584
 Thousands of baby penguins wiped out as  Antarctic ice shelf collapses

Thousands of emperor penguin chicks drowned when the sea-ice on which they were raised was destroyed in severe weather.

Scientists from the British Antarctic Suvery (BAS) say the colony at the edge of the Brunt Ice Shelf in Antarctica’s Weddell Sea collapsed in 2016.

In three years, adult birds are showing no sign of trying to re-establish the population.

A giant iceberg is now set to disrupt the site so repopulation would have been futile, scientists say.

Dr Peter Fretwell and Phil Trathan spotted the disappearance of the so-called Halley Bay colony in satellite pictures.

The Brunt Ice shelf population, which had sustained an average of 14,000 to 25,000 breeding pairs for several decades (5-9 per cent of the global population), seemed to disappear overnight.

Phil Trathan, head of conservation biology at the BAS who wrote the study, says the breeding pair population has increased significantly at a nearby location, but not enough.

The nearby Dawson-Lambton breeding area, which had been home to a couple thousand pairs, increased to 11,117 pairs in 2017 and 14,612 pairs in 2018, the study said.

The Brunt ice shelf has not reformed in recent years with Dr Fretwell saying: "The sea-ice that's formed since 2016 hasn't been as strong.

“What's troubling isn't that part of the colony has moved to Dawson-Lambton, it is that scientists thought of Halley Bay as a climate change refuge in one of the coldest areas of the continent "where in the future you expect to always have emperors," Trathan said.

Scientists blame the sharp decline on climate and weather conditions that break apart the "fast ice" - sea ice that's connected to the land - where the emperor penguins stay to breed.

They incubate their eggs and tend to their chicks - one per pair - on ice.

After breeding and tending to the chicks, the penguins move to open sea.

“Storm events that occur in October and November will now blow it out early.

“So there's been some sort of regime change. Sea-ice that was previously stable and reliable is now just untenable."

The team says the sensitivity of the Brunt colony to shifting sea-ice trends does illustrate the impact that future warming in Antarctica could have on emperor penguins in particular.

Research suggests the species might lose between 50 and 70 per cent of its global population by the century’s end if sea-ice is reduced at the rate computer models envisage.

Dr Trathan told the BBC: "What's interesting for me is not that colonies move or that we can have major breeding failures - we know that.

“It's that we are talking here about the deep embayment of the Weddell Sea, which is potentially one of the climate change refugia for those cold-adapted species like emperor penguins.

"And so if we see major disturbances in these refugia - where we haven't previously seen changes in 60 years - that's an important signal."

“What's troubling isn't that part of the colony has moved to Dawson-Lambton, it is that scientists thought of Halley Bay as a climate change refuge in one of the coldest areas of the continent "where in the future you expect to always have emperors," Trathan said.

Scientists blame the sharp decline on climate and weather conditions that break apart the "fast ice" - sea ice that's connected to the land - where the emperor penguins stay to breed.

They incubate their eggs and tend to their chicks - one per pair - on ice.

After breeding and tending to the chicks, the penguins move to open sea.


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