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Tracking the great hunter of the sea

Great white sharks are both mysterious and terrifying, but a Fallbrook-based Marine research center has made it a goal to learn more about the life cycle of these elusive animals that rule the ocean.

The Marine Conservation Science Institute (MCSI) – which is comprised of Dr. Michael Domeier and Nicole Nasby Lucas and supported by The George T. Pfleger Foundation and the Offield Family Foundation – is on the forefront of understanding the life and reproductions cycle of the great white shark.

Domeier and Lucas have studied the sharks found at Guadalupe Island, a small isle found 100 miles off the Mexican coast, for over ten years.

Before beginning their studies, shark studies had been limited because of the difficulty that comes with studying the creatures. As sharks are difficult to capture or handle, most of the available information has come from dead specimens or from shore-based research stations.

To grow their research abilities, Domeier and Nasby began using pop-up satellite tags that are inserted into the backs of the sharks (as close to the dorsal fin as possible) as they are lured close to the boat with large tuna carcasses.

The tags remain on the sharks for anywhere from two weeks to one year, giving MCSI valuable information on the behavior and movement of white sharks including swimming depths, temperatures encountered, daily patterns and migratory movements. This system has allowed the team to create the most comprehensive study of white sharks in the world

“The tag gives us a precise estimate of the sharks’ location in real time,” said Domeier. “Every time the dorsal fin comes above water, the information is sent to a satellite and then sent to us via the Internet.”

In order to use this groundbreaking technology, the team had to be able to catch the sharks, restrain them long enough to insert the tag securely, and release the fish quickly, without hurting the animal or the researchers. The tag can run for up to two years, transmitting vital information to the team.

In order to do so, a team of world-class anglers and their ship were commissioned. Mark Fischer, the vessel’s owner, asked for permission to film the work in lieu of payment.

The shark is captured by using a giant hook and bait. Once the shark is caught, the ship crew tires out the great white shark in question before reeling it by using a line that can hold 5,000 pounds along with four fixed buoys creating hundreds of pounds of drag that eventually wear down sharks’ resistance, allowing crew members to hand-reel them in safely. The animal is then towed onto a special cradle that lifts the shark out of the water. A hose is inserted into the animal’s mouth so that water can stream into its gills while being worked on, and its tail is secured to keep men from being swept off.

“It’s essentially the same process as catching a marlin,” said Domeier. “We have to tire out the shark so it isn’t thrashing around on deck and secure it. This doesn’t hurt them, as they respond to pain differently.”

The first catch the MCSI team caught was relatively small, said Domeier.

“The first great white we caught was only 11 feet long,” said Domeier. “We’re now catching sharks that are about 18 feet.”

The capture and release strategy implemented by MCSI, along with the detailed underwater photography of the sharks found near Guadalupe Island, has allowed the team to easily identify 107 sharks that frequent the area.

“We have a photo identification book system that documents physical features such as pigmentation patterns, the sex of the animal, and any scars and mutilations,” said Lucas.

Upon identifying the sharks, MCSI researchers can study precise actions of each individual shark.

“We have found that while the sharks are loyal to this area, and return after four to six months out at sea,” said Lucas. “While the sharks show great loyalty to Guadalupe Island, the females don’t come back to the island every year.”

According to Lucas, great whites spend a majority of their time offshore, as opposed to what was currently believed.

“It’s usually juvenile sharks – which are fish eaters – found along the coast, or mothers who are about to give birth,” explained Lucas. “We were surprised by how much time mature sharks spend off coast.”

MCSI hopes to learn even more about the sharks’ life cycle by expanding their research area to include a larger portion of the California coast. This will allow the team to further document an ever-elusive animal, and continue to share their findings with the scientific world.

“We were able to present our findings at a symposium in Hawaii,” said Domeier. “We expected about 40 people, but over 100 came to the conference.”

“People are fascinated by sharks, and can’t seem to get enough of them,” stated Domeier.

Lucas hopes that this information will shed light on a creature that has been needlessly slaughtered.

“Great whites are a vulnerable species,” she said. “They are quite rare, and are listed as a threatened species in the Pacific.”

The research team’s voyage, Expedition Great White, was chronicled by the National Geographic Channel, and will be aired in June.

For more information on the Marine Conservation Science Institute, go to http://www.MarineCSI.org.

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