ISLE OF PALMS, S.C. - A man and a 9-year-old boy bitten hours apart while swimming along a South Carolina beach likely suffered shark bites, a marine biologist said Friday.

The waters along a 7-mile stretch of the Isle of Palms, which had been closed following the Thursday incidents, were reopened on Friday to swimmers.

"It sounds from the extent of the bites they likely were shark bites," said Bryan Frazier, a marine biologist with the state Department of Natural Resources who said he would need to see photos to say for sure. "From what I've heard, they probably are shark bites."

The man and the boy, who were both treated at hospitals, were bitten within three hours of each other, said Isle of Palms administrator Linda Tucker.

A man was in stable condition at the East Cooper Regional Medical Center Friday after undergoing surgery, said Pam Tucker, a spokeswoman for the hospital. She said she could not release his name or nature of his injuries.

The incidents occurred about four miles apart along the shore of the resort island lined with large beach front homes.

"Off of South Carolina it's a pretty unusual occurrence," Frazier said. "We average generally about four shark bites a year. To have two in the same area is definitely an unusual occurrence but I highly doubt they were related."

"Certainly in our area, it's a case of mistaken identity," he said. "I don't like to call them shark attacks off our area, I think of them more as shark bites. It's grab and release."

Tucker said both the beach and the water were being patrolled on Friday.

There are few bull sharks in South Carolina waters. Those are the ones often involved in violent attacks in Florida, Frazier said. He said the bites could have been caused by any of a half-dozen types of sharks common to the South Carolina coast.

There had been no confirmed reports of unprovoked shark attacks in South Carolina this year, said George H. Burgess, the director of the International Shark Attack File.

There have been 56 confirmed, unprovoked shark attacks along the state's coast since 1837. The last fatal attack was in 1852.