Be nice to White Sharks - Dive Malibu

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Posted by Gari Baldy on April 13, 2011 at 20:21:53:

Although popular for their high-action shark drama, a National Geographic documentary team has uncovered a key that could bring marine biologists closer to understanding the life cycle of the mysterious great white shark.
"Finally, one of our great white sharks, she led us to a place where scientists never ever dreamed she would go," said Shark Men expedition leader Chris Fischer. Amy, a female shark that the team had tagged with an electronic tracking device, had led them to a shark birthing ground - right off the coast of Malibu, Calif.

"The scientific information that could be gathered from the beginning of the life cycle of the shark could be immense," said Professor Vincent Gallucci, a shark biologist at the University of Washington.

When Fischer and his team set out to catch and track great whites, they discovered a lapse in the presence of females returning to an island about 150 miles off the coast of Mexico.

"These sharks would show up every year off of Guadalupe Island and then they would leave after four months or five months," Fischer said. "The males would come back every year and the females would come back every other year. Nobody knew where those females went in the off year and that was a big part of the mystery we were trying to solve."

Much of the mystery, however, remains.

Little is known about the life cycle of the massive great white, or Carcharodon carcharia, which can grow nearly 20 feet in length. Information such as where they breed, their migration patterns and where they go to give birth is key to the survival of the species, said Fischer.

"It's pivotal. The giant things of the ocean - we just don't know anything about them," he said. "Now we're actually collecting the data to understand their lives to protect those areas where they're vulnerable."

Gallucci, however, fears that it is that data that could put the animal at risk.

"If conservation NGO were to mount an effort to protect this area where there are lots of young great whites, that would be a positive," Gallucci said. "If it attracts fishing boats from Southern California, it would be a negative."

The protection of this nursery area, he said, would be critical for the shark's survival.

"Just based on (natural) selection, it would be an optimal area for the survival of the pups," he said. "There would be food available, there would be a suitable temperature so the sharks would thrive and it might be a place where others predators are not."

"Until we understand where they feed, where they breed, where they give birth and how the babies move around, we can't effectively modify our ocean policy to make sure they have a bright future," Fischer said.

The great white is considered a "vulnerable" species, according to the International Union for Conservation of Nature and Natural Resources. Off of the West Coast in particular, some populations of sharks have declined by nearly 80 percent since the 1970s.

The Shark Men, which includes Fischer along with a marine biologist and crew, have tagged more than 20 great white sharks since 2007, he said. It's a feat that involves luring, hooking and hoisting the massive creature out of the water on a giant forklift to collect blood, sperm and other data. Before being released, the creature's fin is equipped with a tag that allows the team to track their movements every time the appendage emerges from the water.

"The data we've gotten is groundbreaking," said Fischer. "When we set out in 2007 to do this, no one had ever done it before [...]there was no book on how to do this - no one knew what was going to happen."

And surely no one expected that the adventure would lead them just off of the coast from Sunset Boulevard.

"It was crazy, while we were catching these juvenile baby white sharks; we were watching people surf just 3 - 400 yards away."

Fischer and his team will hit the California coast breeding ground this Sunday on Shark Men, 9 PM ET/PT on the National Geographic Channel.

Brandi Kruse, 97.3 KIRO FM Reporter

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