In the space of five hours sharks attacked three surfers at a single Florida beach, while a teenage boy was bitten on a second beach.

The first victim, a 43-year-old local man, was bitten on his lower leg and ankle and rushed to a hospital nearby after a Sunday morning attack (18 September) off New Smyrna Beach, which has been dubbed the "shark bite capital of the world."

Twenty minutes later a second surfer, 36, suffered severe lacerations to both hands in another shark attack. He was also taken to hospital for treatment where he was scheduled to undergo surgery to repair significant damage.

Brandon Jurekovic, a 29-year-old New Smyrna Beach surfer, saw him stumble ashore, screaming.

"He was holding his one hand with his other hand and it was obviously blood red," Jurekovic told the Daytona Beach News-Journal. "He was screaming at the top of his lungs, 'Help, help.' "

"I'm still shook up about what happened," the surfer posted on Facebook page. "But I'm very grateful that I survived and will get to recover. Many people are not so lucky.

"Keep me in your thoughts as I undergo reconstructive surgery to repair my hand."

The third surfer, age 16, suffered a minor laceration to his thigh in an attack in the afternoon and was treated at the scene.

About 75 miles (121km) to the south, a 13-year-old boy was also bitten by a shark soon after while surfing at Indian Harbour Beach.

"I took a wave and I jumped off of my board. That's when I felt something hit my leg. I looked down and my foot was just gushing blood," Joshua Michael Stuart told Florida Today. The wound was closed with staples at hospital.

None of the injuries was life-threatening. September is the month shark attacks are most likely to happen in Florida.

New Smyrna beach is considered the most dangerous in the world for attack by the many sharks prowling the waters there.

There have been 12 attacks so far this year in Volusia County, where the beach is located. The International Shark Attack File, a non-profit organisation that tracks shark-human interactions, reports 275 attacks in that part of Florida since 1882.

The number of unprovoked shark attacks in the world hit a record 98 in 2015, but Volusia's attacks are already up year-to date.

Most of the world's attacks in 2015 — 76.5% — occurred in North America, which tallied a total of 59 unprovoked attacks, and Florida topped the list.

Australia followed with 18, and South Africa had eight.