A teenage boy has been critically injured in the second shark attack in three days along the Florida coast.
Shark attacks are much rarer than popular fears would suggest
The victim, who has not been named, was taken to hospital after being bitten in Cape San Blas, about 100 km (60 miles) from the scene of Saturday's death.
Jamie Marie Daigle, 14, had been swimming on a boogie board with a friend about 100 yards (91 m) from shore when a shark tore into her leg.
The same shark is not thought to be responsible for Monday's attack.
Erich Ritter of the Shark Attack Institute said the girl was probably attacked by a bull shark, based on measurements of the bite wounds.
After Saturday's attack, a 20-mile (32-km) stretch of beach was closed to the public, but re-opened on Sunday with twice the number of lifeguards on patrol.
On Monday, off-duty deputies were called in to step up beach patrols and watch for sharks from the air and the water, the Associated Press reports.
Shark attacks remain rare, with 55 unprovoked attacks in 2003, according to the International Shark Attack File.