Wednesday, February 6, 2013

Penguin population up in Eastern Antarctica

Phil Ashley-Brown reported this story on Thursday, February 7, 2013


TONY EASTLEY: A study into Adelie penguins in Eastern Antarctica has shown a 75 per cent increase in their population over the last 30 years.

Meanwhile Adelie penguin populations have plummeted on the other side of the continent, believed to have been caused by reductions in krill and sea ice melting.

The study by biologists Louise Emmerson and Colin Southwell is the biggest of its kind ever undertaken and it will be completed this summer season.

Phil Ashley-Brown reports from Casey Station in Eastern Antarctica. His report begins with the voice of biologist Colin Southwell.

(Sound of penguins calling)

COLIN SOUTHWELL: This is a call that penguins make when they're changing partners...

(Sound of penguins calling)

...when one partner comes in from foraging and takes over from the incubation duties on the nest.

(Sound of penguins calling)

We're walking across the snow here to Newcomb Bay. And out in Newcomb Bay there are penguins coming in from foraging trips. They're breeding now so they're going out to forage to get food for their chicks and there are some birds coming back in right now.

PHIL ASHLEY-BROWN: Over the last seven years biologists Louise Emmerson and Colin Southwell have surveyed penguins across a 4,000 kilometre stretch of East Antarctic coastline including 150 islands.

COLIN SOUTHWELL: The equivalent of that in Australia would be all the way from the east coast to the west coast of Australia, so it's a really big survey. I think it's, as far as we know, the biggest direct survey of penguins that has ever been undertaken in Antarctica.

PHIL ASHLEY-BROWN: The survey was aimed at finding out whether the population has changed, to inform policy decisions around fishing.

LOUISE EMMERSON: We're doing all these tracking studies to figure out where they're foraging and what environment they're foraging in, particularly in relation to sea ice because that is an aspect of the environment that is already showing changes in relation to climate change.

PHIL ASHLEY-BROWN: Where are they foraging? How far out?

LOUISE EMMERSON: The penguins at Casey are foraging around 400 kilometres away from the breeding site during the summer period. We've also done some previous studies on the winter foraging and during that period they're travelling up to three and a half thousand kilometres away from the breeding sites.

PHIL ASHLEY-BROWN: You've seen some big changes in the population here. How big have the population changes been?

COLIN SOUTHWELL: We've found that the populations across East Antarctica have increased by around about 75 per cent over the past 30 years.

PHIL ASHLEY-BROWN: Do you know why the increase has been so big?

COLIN SOUTHWELL: Well we've only gotten to the point where we can say that the population changes have occurred and they're of that extent.

Some populations are increasing more quickly than others. In some areas they've remained steady. And we're hoping that there might be differences in environmental conditions of those regions that will give us some insights into why penguins are changing so much in some areas and less so in other areas.

PHIL ASHLEY-BROWN: Across the continent on the Antarctic Peninsula the opposite is having. Adelie penguin numbers are dramatically decreasing. Biologists suspect it's due to sea ice melt and Dr Southwell doesn't think the population is moving to the east.

COLIN SOUTHWELL: Well we don't know for sure but it's hard to imagine that movement on that scale, a transcontinental scale, could happen.

(Sound of penguins call)

TONY EASTLEY: Biologist Colin Southwell. Reporter Phil Ashley-Brown travelled to Casey Station courtesy of the Australian Antarctic Division's media program.

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