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American Association for the Advancement of Science
Great White shark swims laps in the ocean
A great white shark swam across the Indian Ocean twice in nine months. The female shark swam from South Africa to Australia and then back to South Africa, according to a new study.
If lots of other great white sharks make similar trips, then great white sharks could be in more danger from large-scale fishing operations in the open ocean than people generally imagine.
The scientists named the shark "Nicole" in honor of the Australia actor and white shark lover Nicole Kidman, said Science author Ramón Bonfil from the Wildlife Conservation Society in Bronx, New York.
Nicole is a record-breaking shark. Her swim is the first concrete link between the great white sharks that live in South Africa and the great white sharks that live in Australia. This swim is also the first known round trip swim of an individual shark across an ocean. It is also the fastest back-and-forth swim across an ocean of any marine creature.
The shark scientists tracked the movements of the female great white shark's 99-day swim from South Africa to Australia. They attached a gadget to her that communicated information on her swim to a satellite. About six months after Nicole arrived in Australia, researchers spotted her off the coast of South Africa once again. Finding her in South Africa again meant that she made a round trip across the Indian Ocean. They identified her using pictures of the triangle-shaped dorsal fin on her back.
During Nicole's approximately 11,100 kilometer trip from South Africa to Australia, she swam close to the ocean surface more than half of the time. She also spent lots of time deep in the ocean. Swimming near the surface may have allowed the shark to use the stars, the moon or planets as a kind of compass or map, but the scientists are not sure about this.
In the new study, the researchers also describe the movements of other great white sharks, including long-distance swims along the southeastern South African coast. Many great white sharks return to their home waters after long trips, the scientists found.
This research appears in the 07 October 2005 issue of the journal Science.