NEW SMYRNA BEACH -- Nearly 40 percent of the shark attacks around the world this year have occurred along a single stretch of Florida's coastline that is considered one of the state's best surfing spots.

"Volusia County is perhaps the shark attack capital of the world," professor of marine biology at the University of Miami Samuel Gruber said.

Six people were bitten by sharks off New Smyrna Beach over the weekend, raising to 15 the total of shark attacks along more than 50 miles of Volusia County's popular beaches this year, according to University of Florida shark expert George Burgess.

The Volusia County Beach Patrol said that there have been 17 attacks along the county's beaches.

Burgess, director of the International Shark Attack File in Gainesville, said 29 of this year's shark attacks have been in the United States.

Lifeguards on Monday twice cleared a quarter mile stretch of New Smyrna Beach for a third day in a row after two shark sightings.

But surfers, lifeguards and shark experts were quick to point out that the shark encounters are nothing new. Surfers and kayakers regularly see them in the surf. And last Easter weekend, there were seven shark attacks here over a two-day period.

"They're always there. You just have to be careful and know what's around," surfer Leonardo Pedreros said.

A combination of murky water, caused by recent heavy rains pouring or stirring up silt into the water, and an unusually crowded beach due to a surfing contest, may have caused the sharks to mistake humans for fish.

"When the water is clean, there is no problem because the sharks can see,'' said Dan Jacocks, 44, who kayaks every morning off New Smyrna Beach, about 15 miles south of Daytona Beach.

New Smyrna Beach and adjoining Ponce Inlet hold a diverse population of bait fish that attracts the sharks and may explain why the area leads the world in shark attacks, Burgess said.

"It's a smorgasbord of food coming back and forth," he said.

Jaison Valentin should know. A shark mistook his left hand for food Saturday while he was surfing off New Smyrna Beach. The shark left a 2-inch gash on the backside of his hand, requiring surgery to repair torn tendons and ligaments.

"It took a nice big chunk out of my hand," Valentin said. "I knew to get the hell out of the water."

Another victim, 17-year-old Becky Chapman underwent surgery at Bert Fish Hospital but was in good condition Monday. Hospital spokeswoman Kate Holcomb said that Chapman was to be released later in the day.

Sharks also have been on the attack this month in the Bahamas, where two Americans were bitten in the leg. Both are recovering at a Miami hospital, one after having his leg amputated.

An 8-year-old boy was attacked by a bull shark in July in Pensacola, on Florida's Gulf Coast. Jessie Arbogast's arm was severed and he lost nearly all his blood. The arm was reattached but Jessie remains in a light coma.

Last year, there were 79 shark attacks worldwide, 51 in the United States, 34 in Florida and 12 in Volusia County, Burgess said.

Volusia County currently is on pace to surpass its record for shark attacks (18) set in 1996.

Surfer Sean Nolan saw one advantage to the shark attacks.

"It thins the line," said Nolan, 24, a student. "Usually it is so crowded. Maybe this will keep people away."