Remarkable swim patterns of Hobart’s penguins
THE first ever study into the sea adventures of Tasmania's little penguins has revealed they share a practice familiar to many Tasmanians: a daily commute between work and hungry mouths at home.
IMAS and CSIRO researchers fitted 29 little penguins with GPS trackers to see what they get up to when at sea.
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The study found the penguins all stayed out for less than 24 hours - although the distances they travelled all varied depending on their home base.
The focus penguins were from three different colonies south of Hobart: near Kingston, on Bruny and Wedge islands.
IMAS Associate Professor Mary-Anne Lea said the little penguins would head out in the morning, spend the day foraging and then return to feed their chicks.
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"They're daily commuters," Assoc Prof Lea said.
"They don't travel long distances because they can only get to a certain point before they need to turn around and come back again."
Their range was generally within 30 to 50km of their breeding grounds. The greatest maximum distance was by a Bruny penguin that travelled 71km, while the shortest was a Kingston penguin who covered 25km.
The study was the first to investigate the at-sea habits of the vulnerable species, which aims to shed light on how they adapt to subtle changes in environmental conditions to find food.
The trackers revealed the birds remain relatively close to the coast, exhibit a high level of variability between colonies while accessing a wide variety of sites, and are finely attuned to environmental influences such as water depth, salinity and temperature.
The study's lead author, former IMAS Honours student Lachlan Phillips, said conditions in Storm Bay were highly variable and affected by a wide range of factors, including the East Australian Current, cold sub-Antarctic waters in winter, and freshwater from the Derwent and Huon rivers.
"Previous studies have looked at how environmental conditions influence marine predator behaviour on a broad scale but little is known about the impact of localised factors, such as those in complex environments like Storm Bay."
The GPS devices recorded data at a one to two-kilometre resolution every hour, before being removed after 24-hours.
Mr Phillips said penguins from the three sites behaved quite differently while foraging and their behaviour was influenced by their environment.
Assoc Prof Lea said getting a more complete understanding of penguin activity and behaviour around Tasmania would require longer-term research to study colonies across the State.
