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SANTA CRUZ— Great white sharks don’t just troll the cold waters off a select few coasts — they head to warm waters, sometimes hundreds of miles away, and dive deeper than researchers thought, according to a study published Thursday. 

Scientists who tracked six adults tagged off the coast of central California had thought the animals would stick relatively close to shore. Instead, using small data transmitters, they found the creatures spent months in open ocean. 

One shark, named Tipfin, spent 40 days migrating from the Farallon Islands near San Francisco to Hawaii, where it stayed four months. Three others swam hundreds of miles to the warm waters west of Baja California. Only two stayed close to the coast off San Francisco. 

“I was shocked by the results,” said one author, biologist Burney J. Le Boeuf of the University of California, Santa Cruz. “It turns out they’ve got a life at sea.” 

A need for new mates, or even a different diet, could explain the long migrations, Le Boeuf said. 

He and others, including scientists from a joint project of Stanford University and the Monterey Bay Aquarium, reported the results in the Jan. 3 issue of the journal Nature. 

The offshore travel of the sharks lasted at least five months, suggesting it’s important to shark life, the researchers said. They could not pinpoint the exact reason for the migrations. 

The researchers also were surprised by the depths at which some sharks swam. 

“The sharks went straight out across the open ocean, diving to depths of 700 meters,” Le Boeuf said. “In all our observations before, they were never observed below 100 meters.” 

The researchers tracked the animals with tags that continuously recorded water depth, temperature and light levels, and then detached from the animals on a pre-set date. The tags popped up to the surface and transmitted data to satellites. The light levels let scientists track the animals’ movements. 

The data then beamed to servers in France and Maryland, which triggered an e-mail to researchers. 

Previous studies had only tracked great whites for short periods near seal colonies such as the Farallones and Ano Nuevo, according to Barbara Block of the Tuna Research and Conservation Center at Stanford’s Hopkins Marine Station. 

She said her first reaction to the new study was to inform a fisherman friend in Hawaii of the results. 

“I said, ‘Do you know there’s a great white shark swimming off of Maui right now?’ ” she said. 

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On the Net: 

http://www.pelagic.org/ 

http://www.ucsc.edu/