STUART, Fla. -- Sharks killed a kite surfer Wednesday off the Atlantic coast of South Florida in the state's first fatal shark attack since 2005, West Palm Beach TV station WPBF reported.

The Martin County Sheriff's Office identified the victim as Stephen Schafer, 38, of Stuart.

A lifeguard noticed Schafer, who appeared to be in distress, at about 4:15 p.m. Officials said he was in an unguarded area south of Stuart Beach.

"He was just hanging onto his board -- not normal activity for a kite surfer," said Daniel Wouters of Martin County Fire Rescue. "Normally, the wind comes and they pick back up and they go off, but he had been hanging onto his board."

The lifeguard went into the rough water and paddled to the victim on a rescue board. Officials said sharks were still circling the surfer as the lifeguard put him on the board and paddled back to shore.

"When (paramedics) got there, they found a number of sharks in the water and they found the victim had been bitten several times," Wouters said. "They were able to maneuver him onto the kite to basically somewhat protect him and bring him on shore."

Schafer was pronounced dead at the hospital, according to the Martin County Sheriff's Office.

Authorities are investigating what types of sharks were involved and whether multiple sharks bit Schafer. Beaches remained open Thursday.

Shark attacks, especially fatal ones, are extremely rare, said George Burgess, a leading shark expert who directs the International Shark Attack File at the University of Florida's Museum of Natural History.

The attack on Schafer was the 14th deadly one in the state since 1896.

"Internationally, we've been averaging four fatalities per year, despite the fact that there are billions and billions of human hours spent in the sea every year," Burgess said Thursday. "Your chances of dying in the mouth of a shark are close to infinitesimal."

Friends said Schafer always followed the buddy system while surfing and were surprised he was in the water alone.

"We always know that (sharks) are out there. You see them this time of the year," said Teague Taylor, a childhood friend who says Schafer taught him to surf. "It's hard to believed that such an experienced waterman would make that one mistake."

Schafer, a gifted artist and graphic designer, was drawn to the water as a child. He surfed competitively and later started sailing, windsurfing and kiteboarding. Kiteboarders surf across the water on boards strapped to their feet, using large curved sails to pull them along.

"He had to be around the water," said Taylor, who manages a local surf store.

The U.S. leads the world in the number of unprovoked shark attacks, some deadly, some not, with about 1,032 documented since 1670, according to the International Shark Attack File. Of those, 50 were fatal. Florida leads the world with more than 600 attacks.

The last fatal shark attack in the state was in 2005 off the Florida Panhandle, where a 14-year-old Louisiana girl was attacked while swimming on a body board about 100 yards off shore.

"Florida as a geographic entity has more than any other place in the world," Burgess said, noting that most attacks are minor, "the equivalent of a dog bite."

While attacks are rare, Burgess said, people still need to be careful in the ocean.

"We need to respect it. When we enter the sea, there are certain risks that we should expect," he said.

However, Burgess noted that this time of year there are typically fewer shark attacks in Florida because temperatures are cooler and not as many people are in the water.

He said sharks are lining "up in South Florida getting ready to move north" as temperatures begin to warm.

"The sharks gradually move their way northward and disperse," Burgess said. "The message to take home is this is a rare and unusual event. It should put the antennae up for people, in terms of, 'Yeah, we need to be careful when we enter the sea, but we need to do that every time because we're never guaranteed safety 100 percent of the time when we enter a wild world.'"