Thursday, Apr 24, 2014
Local News

Scientists track great white sharks off Fla.


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JACKSONVILLE - The search for great white sharks just off the coast of Jacksonville is about to get a lot more serious.

By the end of this month, the University of North Florida's shark-­research program expects to place as many as 10 sensors in the Atlantic.

The devices will be near the beach, perhaps a half-mile or mile from the sand. The great whites come in close.

The nonprofit shark research group Ocearch last January tracked a 16˝-foot great white named Mary Lee in the surf zone in Jacksonville Beach.

They then brought their research vessel on an expedition to Jacksonville and caught and tagged 14-foot Lydia. Meanwhile, the satellite tag on Katharine showed that shark hanging around near Cape Canaveral.

GPS devices, caught by satellite every time they rise to the surface, track the Ocearch sharks.

The sensors store information but can't transmit it instantly; it will have to wait until researchers travel to them and download the data.

Jim Gelsleichter, a shark expert at UNF, said his school's sensors will most likely be attached to buoys in Nassau Sound, Fort George Inlet, the Mayport area, Jacksonville Beach, Ponte Vedra Beach and St. Augustine.

Chris Fischer, founder of Ocearch, is on an expedition in the Galapagos Islands. He said he was "thrilled" by the new sensors off Jacksonville, calling them a crucial link in researchers' understanding of great whites.

Placing the sensors close to shore is a big plus, too, Fischer said. The tracking devices show some great whites spend much more time poking into inlets and cruising along beaches than was once believed.

"What's really surprised us is the coastal portion of their life, which particularly seems significant in the Southeast," he said.

Ocearch's high-profile spottings of great whites in the area created a buzz. Mary Lee, a celebrity shark, even has a Facebook page.

It's unclear whether there are more great whites off Jacksonville.

"Finding white sharks is tough," said Greg Skomal, a shark expert at the Massachusetts Division of Marine Fisheries who accompanies the Ocearch vessel on its expedition to Jacksonville. "Counting them is even tougher."

But Skomal said there has definitely been a big rebound in the great white population off Cape Cod.

Thanks to tracking devices implanted in Cape Cod sharks, scientists know they frequently range as far south as Florida. So it seems likely that more Cape Cod sharks equals more Florida sharks.

"I don't think it's any reason to run up and down the beach screaming," UNF's Gelsleichter said. "But the scientist in me is curious about it."

Gelsleichter, an assistant professor of biology, has been fascinated by sharks since he saw "Jaws" at age 6.

He's now directing the university's Shark Biology Program, which studies the many species of sharks in the area. Great whites, the apex predator of the ocean, attract the most media attention, even if they're not much of a threat to humans on the East Coast.

In July 2012, a swimmer was bitten off Cape Cod and survived; that was the first great white shark injury there in 75 years, Gelsleichter said.

Meanwhile, the International Shark Attack File at the Florida Museum of Natural History said there has not been a single documented instance in Florida's recorded history of a great white attacking a human.

Scientists once thought the animals summered off Cape Cod and wintered in the Southeast, a pretty simple pattern.

But it looks now that they're off the Southeast coast, even during warmer months. "We're seeing good evidence to show that the animals are not just winter residents," Gelsleichter said.

UNF's devices will be able to pick up any of the Ocearch-tagged sharks, along with about 20 others tagged by harpooners off Cape Cod. Each shark emits a distinct signal, so scientists will be able to identify and track each one.

UNF already has three devices working, but they're at popular diving spots far offshore. They picked up the presence of two great whites last winter.

Much remains to be learned about the travel patterns and life cycles of the great white.

"I think definitely that we're an important part of the puzzle," Gelsleichter said.

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