A shark bit a teenage surfer`s leg to the bone off a Sydney beach early Sunday -- the Australian city`s third attack in as many weeks, police said, according to AFP.
The 15-year-old boy was surfing with his father at Avalon, one of Sydney`s northern beaches, when the shark struck, the NSW Police Force said in a statement.
"The father heard a scream and turned to see his son thrashing about in the water," police said.
Family friends said the man, an experienced surf lifesaver, dragged his son to shore and administered first aid, using his surfboard leg rope as a tourniquet.
Ambulance officers said the teenager was bleeding heavily from severe lacerations to his leg. They stabilised him, treated him for pain and then airlifted him to the Royal North Shore Hospital, where he was in a stable condition.
Police said it was too early to say what type of shark attacked the boy but experts would examine the bite to determine the species responsible.
They closed five beaches on Sydney`s northern peninsula as a surf lifesaver helicopter swept the area looking for the predator.
It was Sydney`s third shark attack in 19 days, with the city`s beaches packed with locals and tourists during the summer months.
On February 11, a navy diver was attacked by a bull shark in Sydney Harbour, not far from the famous Opera House, suffering serious injuries that forced doctors to amputate an arm and a leg.
Thirty-six hours later, a 2.5-metre (8.2-foot) great white -- the maneaters made famous in Steven Spielberg`s "Jaws" -- savaged a surfer off Sydney`s most popular tourist beach, Bondi.
The man`s hand was left hanging by a three centimetre (1.2-inch) flap of skin but surgeons managed to reattach it after using leeches to restore blood flow.
Despite the danger, about 900 swimmers braved the waters around the Opera House Sunday for the annual Sydney Harbour Swim Classic.
Competitor Tony Hogan, 43, said he had heard about the Avalon attack before the swim but was not worried about competing because organisers had enacted extensive safety measures.
"It`s a safety-in-numbers type thing," he told national news service AAP.
"Look, they patrol it pretty well, but there`s a lot of safety attached to it, whether there`s snorkellers or lifesavers on their boards or helicopters over the top."
Some experts believe cleaner waters around Sydney and a ban on commercial fishing in the harbour have increased fish stocks, attracting more sharks to the area.
While shark attacks are not uncommon off Australia`s vast coastline, experts said no one had been bitten by a shark in Sydney Harbour for more than a decade and the last fatal attack was in 1963.
A total of 194 people have been killed in shark attacks in Australia over the past two centuries, records show. Researchers are quick to point out that more people die from bee stings and lightning strikes.
Authorities have warned the city`s beach-goers to avoid going out in the water at dawn and dusk, the main feeding time for sharks.
