Wednesday, May 18, 2005

Great white shark released from Montery is doing well

A great white shark that spent a record 198 days in captivity before her release from the Monterey Bay Aquarium thrived during her first month in the wild, according to data from a temporary tracking tag released Monday.

The female shark swam up to 200 miles offshore and to depths of about 800 feet in the 30 days since her March 31 release at the southern tip of Monterey Bay, said Randy Kochevar, an aquarium marine biologist and researcher with the Tagging of Pacific Pelagics project.

The findings are limited but answer a pressing question as the aquarium embarks on another season of shark research that could lead to another in captivity. The data confirm that the shark's stay in Monterey didn't hurt its ability to thrive once it was set free.

"An animal of that size and that age could not survive more than a few days without food," Kochevar said. "When we see an animal that has been actively moving around for 30 days, we know this is an animal that is successfully hunting.

This is an animal that's doing just fine."

The shark was captured off Orange County by halibut fisherman in August and spent several weeks in an offshore pen in Malibu before being moved to the Monterey aquarium in September. Nearly 1 million people saw her swim around the massive Outer Bay exhibit during her stay in Monterey. The previous captivity record was 16 days.

In late March, she was returned to the Pacific near Point Pinos after she began exhibiting hunting behavior and biting tank mates. She also had gained 100 pounds, and there was concern she might quickly grow too big for easy removal.

The satellite tracking tag was attached and set to pop off after 30 days. It was found May 5 west of Point Arguello, near Santa Barbara.

The tag, which recorded the shark's location and other data every 10 seconds, also found she spent most of its time in surface waters with a temperature of about 58 degrees Fahrenheit. In deeper dives, temperatures dropped to less than 48 degrees.

Her preferences are "consistent with those returned from tags we've placed on other young sharks as part of the project," said Kevin Weng, a researcher with Hopkins Maine Station of Stanford University, which is one of the aquarium's partners in the white shark field project.

Because the tracking device was designed to pop off after a month, the shark's whereabouts are now unknown. But there's still a chance she might be found again: The shark carries identification numbers that would be visible if she's ever caught.

"Because she was a fairly small animal, we were really hesitant to try to attach multiple tags to her," Kochevar said. "These pop-off tags are a relatively large piece of equipment for an animal to drag around."


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