Green sea turtle reveals oceanic highway

Narelle Towie, news.com.au 28 Apr 08;

AFTER a remarkable 1400km journey, she has finally arrived in Western Australia.

For two months green sea turtle Dorte has hitch-hiked the ocean currents from Java to WA in search of shallow waters full of lush green sea beds.

She is one of the first green turtles whose migratory route has been tracked by conservationists, who plan to study the lifecycle of this ocean giant.

Dorte, who is thought to be at least 20-years-old, was tagged with a satellite tracking device as she lay a clutch of 136 eggs at a nesting beach in Java.

Scientists believe she is heading to Eighty Mile beach, halfway between Broome and Port Hedland.

“After laying her clutch she is now in her feeding phase. The best place to find sea grass beds is in shallow coastal waters and the west coast of Australia is perfect in that regard,” the ocean programme manager with WWF Australia, Dr Gilly Llewellyn told PerthNow.

“Dorte’s journey is unique. She has revealed an ‘oceanic superhighway’ that helps us better understand how marine turtles navigate around the world’s oceans as well as highlighting the strong ecological and evolutionary connections between Indonesia and Australia’s Kimberley-Pilbara coast,” she adds.

Although turtles are known to instinctively return to the beach they were born to lay their own eggs, it was previously thought that they do not travel great distances.

The discovery of Dorte's migratory route could be used to influence decisions makers on which areas of the ocean should be better protected, scientists say.

“This new finding throws the spotlight on the true natural values of the magnificent Kimberley marine ecosystem and its link to the Indonesian Coral Triangle to the north – the world’s epicentre of marine biodiversity and the cross-roads of migration routes and breeding grounds for whales, turtles, dolphins and other precious marine species," Dr Llewellyn said.

“We think of Australia as an island, but it is also a cross roads of the world’s oceans.”

Dorte’s tracking device will run out of battery in about six months time and eventually fall off her shell.