A 16-year-old boy is in stable condition after being bitten by a shark in the Gulf Coast waters of northern Florida on Monday. It was the second shark attack in the area in three days. Experts say last year's Florida hurricanes could be the reason why sharks are now closer to popular beaches in some parts of Florida.

Beaches along Florida's northern Gulf Coast were closed on Monday after the second shark attack in three days. One of three boys fishing on a sand bar at Cape San Blas was severely bitten by a shark on Monday.

Sheriff's vehicle patrols  beach in Destin about one mile from where 14-year-old girl was fatally attacked by a shark

The area is about 140 kilometers east of a beach near the city of Destin where Jamie Daigle was killed by a shark on Saturday. The 14-year-old girl was visiting the area with family friends when she was attacked by what authorities say was a nearly two-meter bull shark while swimming about 60 meters from shore.

Tom Dicus, a nearby surfer, managed to reach the girl and bring her to shore, but he says the shark's initial attack was probably to severe to survive.

"She was face down and unconscious," he said. "When I grabbed hold of her, the shark surfaced right next to her and broke off to the left, so apparently I disturbed its feeding. He circled around for another attack but by the time he got around I had her up on my surfboard."

Mr. Dicus says the shark continued to try and attack his surfboard nearly all the way to shore. He says he hit the shark several times with his bare hands before it swam away.

Experts say such aggressive behavior by sharks is extremely rare.

Authorities in the area say Monday's attack could have occurred because the boys fishing were using live bait, and were fairly far out from shore, standing on a sandbar.

Bull shark swims in waters near visitors to Miramar Beach, less than a quarter mile from Saturday's attack site

At a Florida news conference on Monday, Eric Ritter, a shark expert from the New Jersey-based Shark Research Institute, said last year's Florida hurricanes could have altered sand bars in the shallow Gulf waters, allowing sharks to move closer to shore than they might previously have done.

"A changed weather system always does affect the super top predators, but it also affects the entire food chain," he said. "So, yes if you change a sand bar it directly affects the current that will bring in other sharks. We have some indication that the hurricanes from last year created some of the accidents."

Mr. Ritter says so far this year there have been at least eight incidents of sharks attacking humans in Florida. In a normal year there are roughly 30 such attacks, more than anywhere else in the United States, because of Florida's long coastline.