A teenage boy has lost a leg in the second shark attack in three days along Florida’s northwestern coast.

Craig Adam Hutto, of Lebanon, Tennessee, was fishing in waist-deep water about 60 ft (20m) from shore with his brother and a friend yesterday when the shark bit his right thigh, nearly severing it, said Captain Bobby Plair of the Gulf County Sheriff’s Office.

Surgeons later amputated the leg, and the 16-year-old was said to be in critical condition in hospital.

On Saturday, 14-year-old Jamie Marie Daigle died from her injuries after her leg was mutilated by a bull shark about 80 miles (130 km) away, near Destin.

Dr Reed Finne, a cardiovascular surgeon at Bay Medical Centre in Panama City, said that Craig's upper leg had suffered irreparable damage to blood vessels and nerves, and to most of the surrounding muscle.

It was too soon to tell if he had suffered any brain damage from blood loss, Dr Finne added. In 2001, a 9-year-old Mississippi boy, Jesse Arbogast, suffered severe brain damage after a shark tore off his arm as he swam near Pensacola.

"We’re hopeful. He’s young, he’s healthy. He should be OK, but he’s still sick," said Dr Finne. Craig will have more surgery today to clean what remains of his leg, and will be treated for possible tendon damage to his hands suffered when he fought the shark.

The fact that a doctor, some nurses and a paramedic happened to be nearby on the beach and began treatment as soon as the boy was ashore, probably saved his life, said Shane McGuffin, Gulf County’s medical services director.

Karen Eaker, 42, of Horn Lake, Mississippi, saw the attack. She said: "Within five seconds it was obvious there was something wrong. We had heard the word ’shark’ and then we saw the red water and the tug-of-war going on between the brother and the shark."

Gulf County’s Board of County Commissioners closed the county’s beaches until midday today local time. Helicopter crews were to fly over the water to check for sharks before the beaches reopened.

The number of shark attacks rises in the summer because the animals come closer to shore to search for food, said John Tyminski, a senior biologist with the Centre for Shark Research at Mote Marine Laboratory in Sarasota.

But Paula Ramsey Pickett, executive director of the Gulf County Tourism Development Council, said that the attack had not damaged tourist numbers.

"We think this is definitely an isolated incident, even though the timing was poor considering (the fatal attack on Jamie Daigle)," she said. The council was passing out a pamphlet to visitors giving tips on avoiding shark attacks.

Jamie, of Gonzales, Louisiana, had been had been swimming with a friend about 100m from shore in neighboring Walton County when a shark stripped the flesh from her leg. Paramedics and an air ambulance crew were unable to revive her. The beaches reopened the following day.

Florida averaged more than 30 attacks a year from 2000 to 2003, but had only 12 last year, said George Burgess, curator of the International Shark Attack File at the University of Florida in Gainesville. He attributed the drop to the four hurricanes that hit Florida last year, keeping residents and visitors away from beaches.

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