penguin volcano eruption mount currie
A chinstrap penguin covered in ash from Mount CurryPete Bucktrout, British Antarctic Survey

Two erupting volcanoes on sub-Antarctic islands are placing one of the world's biggest penguin colonies at risk. Around a million chinstrap penguins live one the slopes of one of the volcanoes, Mount Curry, and they have been pictured covered in ash.

Peter Fretwell, from the British Antarctic Survey, was one of the scientists involved: "We don't know what impact the ash will have on the penguins," he said. "If it has been heavy and widespread it may have a serious effect on the population."

Researchers from the BAS, which had recently remapped the chain of volcanic island, were alerted to a 7.2 magnitude earthquake in the area. Satellite imagery showed two volcanoes – Mt Curry and Mt Sourabaya on the South Sandwich Islands – were erupting.

Furthermore, images from fishing vessels showed the smoke and ash main volcanic vent from Mt Curry, which is on the west of the island, was blowing eastwards.

Mount curry on Zavodovski Island
Mount Curry on on Zavodovski IslandDavid Virgo

Between a third and a half of Zavodovski (home to the chinstrap penguins) had been covered in ash. The time at which the volcanoes erupted coincided with their moulting period, where they shed their old feathers for new ones, meaning they were unable to leave the island. As well as the chinstrap penguins, Zavodovski is also home to around 180,000 macaroni penguins.

BAS penguin ecologist Mike Dunn said: "As the images were captured during the moult period for the chinstraps, the consequences could be very significant. When the penguins return to breed later in the year, it will be interesting to see what impact this event has on their numbers."

Fretwell added: It's impossible to say [the effect on penguins] but two scientific expeditions are scheduled to visit the region from later this year and will try to assess the impact of the eruption."