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8/14/11

Up Close and Personal With Elusive Shark

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(Smalltooth Sandtiger Shark)

Underwater photographer Francis Perez recently captured rare, detailed images of the enigmatic smalltooth sandtiger shark, which lives in depths of up to 3281 feet.

The sandtiger shark in these images is probably just over 13 feet long. Its "small" teeth are set in rows of 48–56 in the upper jaw and 36–46 rows in the lower. These teeth are used to bite into prey such as other sharks, rays, squid, shrimp, rockfish and more.

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Since last summer, Perez has been on the lookout for the shark, (Odontaspis ferox), in the waters off of El Hierro in the Canary Islands. Perez was recently joined by Pedro Pascual, a researcher at the Spanish Institute of Oceanography. Both are hopeful that the shark will make regular appearances near the island, based on sightings over the past 5 years at the Marine Reserve of the Calm Sea.

We still have much to learn about many sharks, and this species is particularly mysterious. The shark spends most of its time in very deep water, with females only emerging in coastal waters every two years to give birth.

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Up until 1999, no one even knew the smalltooth sandtiger shark existed. In that year, one was spotted off the coast of the Colombian island of Malpelo.

"His presence generated an avalanche of divers who wanted to see and photo the animal," Pascual was quoted as saying in a press release. "In the beginning he was very humble, letting even touch, and now when he detects a diver, runs away, and he is no longer seen for several years."

Some of these sharks weigh about 882 pounds, according to Pascual, so going in for a hug is a risky proposition anyway.

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It's thought these sharks enter the world as cannibals, with the most likely meal his or her littermate. Such behavior evolved many hundreds of years ago, when sharks and other marine life weren't under as much pressure from humans. Nature evolves such solutions to keep in check the populations of keystone predators.

"The smalltooth sandtiger is a species with very slow growth," Pascal said. "He can live more than 40 years, his reproduction is biennial and each female gives birth two calves each time, making the moment even more delicate."

Now that the word is out about the rare shark's presence in the Canary Islands, Pascual is concerned that too many curious divers will scare it away. He advises that "we should set a maximum time of observation, establish quotas and make a waiting list for diving in this area."

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Francis Perez isn't the only one who has experienced a close encounter with a smalltooth sandtiger shark in recent months. In the following video, passengers onboard the submarine "Idabel" at 900-feet deep off Roatan, Honduras, got an up close and almost too personal look at one 10-foot individual. The people you hear in the background are Peter Etnoyer, Fred Boltz, and pilot Karl Stanley.

Discovery News /
Analysis by Jennifer Viegas

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