Johannesburg - A scuba diver from the United States was mauled by a shark off the Rocky Bay coast near Durban on Tuesday, Netcare 911 said.

The 22-year-old man's left leg and both hands were injured, spokesperson Chris Botha said.

The man was diving on the Aliwal Shoal, watching sardines, when he was bitten by the three-metre dusky shark just after noon.

“There is always a danger that the predator will mistake a diver for part of their meal when (the shark) goes into a feeding frenzy,” Botha said.

The diver was part of a team of interns who had been diving with the underwater film company Blue Wilderness.

Botha said the man owed his life to the film team, who managed to stem the bleeding quickly.

He was then stabilised by paramedics before being airlifted to the Albert Luthuli Central Hospital in Durban.

The US embassy had been alerted to the incident and would be kept updated on the man's condition, Botha said.

Mark Addison, who heads Blue Wilderness, said this was the first time he had seen an attack at Aliwal Shoal.

“Taking all that we have observed and learnt over the last two decades, there is no way that one could have known that this individual animal would break all of the rules.

“However, the young diver is our main concern right now... Anyone who comes into our environment is considered to be a member of our family,” he said.

Addison said dusky sharks generally lived offshore, but moved closer when they followed the sardines.

Dusky sharks are listed as “near threatened” on the World Conservation Union red list. - Sapa