Photo: Kangaroo Island is one of the few sites in Australia where penguin colonies from the east and west intermingle. (Supplied: Taronga Zoo)
University of Tasmania zoology lecturer Dr Chris Burridge said they wanted to find out whether penguins would travel from one colony to another to breed. "If a colony was wiped out by a predator, would penguins from other colonies come to help replenish it?" she said.
Over 10 years they took DNA profiles from penguins in colonies along Australia's southern coast from Sydney to Perth and around Tasmania. The researchers found penguins from south-eastern colonies were genetically similar, indicating a high rate of interbreeding among colonies there. The same was true of penguin colonies on the south-west coast.
Around the area of Kangaroo Island you can move only 30 kilometres between two different colonies and they'll be genetically different. ~~~University of Tasmania zoology lecturer Dr Chris Burridge
Dr Burridge said colonies on Kangaroo Island were different, indicating populations there resulted from breeding between penguins from eastern and western coast colonies. "So in south-east Australia we found quite a lot of movement, you can go from Sydney to southern Tasmania to Phillip Island and the penguin colonies are all genetically indistinguishable," she said. "But then around the area of Kangaroo Island you can move only 30 kilometres between two different colonies and they'll be genetically different."
She said there were several possible explanations for the genetic mixing. "It could be just because that's where the penguins have happened to meet, as they've expanded back out from the east and the west," she said. "Alternatively there could be some activity in that part of the world that removed penguins, maybe anthropogenic and now they've only recently recolonised."
Dr Burridge said the interbreeding on Kangaroo Island had likely begun hundreds or even thousands of years ago. The research has been published in the Journal of Heredity.