CHARLES Lindop had just finished riding a wave at Sydney’s Avalon beach yesterday when he heard his son Andrew scream.

Turning to the sound, he saw his 15-year-old boy thrashing wildly in the ocean, being attacked by a predator he could not see.

Andrew had been sitting on his surfboard, watching his father catch an early morning wave, when the shark hit him, sinking its teeth far enough into his thigh to hit the bone.

Mr Lindop, a senior patrol captain at the Avalon Surf Club on the northern beaches, swam to his son and helped him paddle back tothe beach. He wrapped the surfboard’s legrope around the boy’s thigh as an impromptu tourniquet.

The shark attack, which happened at 6.45am, was the third in three weeks and has prompted renewed warning about surfing at dawn or dusk, when sharks feed.

Navy diver Paul de Gelder lost a hand and a leg after being mauled by a 2.7m bull shark in an early morning attack off Garden Island, in Sydney Harbour, on February 11. A day later, 33-year-old surfer Glenn Orgias nearly lost his hand after he was attacked by a 2.5m great white at Bondi Beach at dusk.

Yesterday, two off-duty surf lifesavers, Volker and Mike, who declined to give their surnames, watched Mr Lindop and his son emerge from the surf at the northern end of Avalon beach.

“We loaded up a four-wheel-drive buggy that we’ve got and brought all the equipment up,” Mike said. “Charles knew exactly what he had to do. If it had been two kids alone, it might have been different.”

Andrew Lindop was stabilised by paramedics before being flown by rescue helicopter to Royal North Shore Hospital, where he underwent surgery for bites on his calf, hip and ankle. He was in a stable condition last night.

Local surfers said yesterday’s conditions had made an attack all the more likely. Warm waters — 23C — and coastal rains had attracted large numbers of baitfish to the area, bringing marine predators with them. Local surfer Audrey Styman-Lane, 14, said she had seen sharks chasing fish at South Avalon in the past week, and the mood among surfers had become increasingly wary.

Police and politicians yesterday pleaded with surfers to avoid dangerous times and look for warning signs, such as birds flocking abovethe water.

“Please be wary, don’t swim at dawn and dusk, don’t swim if you see a lot of birds flocking in the water, or if you see a lot of fish and fishermen,” Northern Beaches duty officer Richard Anjelkovich said.

NSW Primary Industries Minister Ian Macdonald said the three shark attacks had followed a pattern.

“All three attacks have been either early in the morning or in the evening, which lines up pretty conclusively to some extent with shark feeding habits,” he said.

“Our thoughts are obviously with (Andrew Lindop) and his family, and our praise particularly goes to the emergency services who responded so quickly.”

Witnesses agreed yesterday the boy’s rescue could not have been handled better, singling out Mr Lindop for praise.

Six northern beaches were closed for several hours yesterday, with shark patrols conducted all the way down to Bondi. Further south, swimmers were ordered out of the water after a shark sighting at Maroubra beach.

While Avalon officially remained closed all day, it was not long before local surfers were back among the waves.

“I’m pretty sure the shark wouldn’t have hung around,” said Dillon Cram, 18. “You have to go back in eventually,”

Shark experts yesterday questioned why, when shark attacks elsewhere in Australia and globally are in decline, the number of attacks and the number of sharks coming near to the city’s beaches has skyrocketed.

Australian Underwater Federation national chair Adam Smith said more than 6000 of the 11,000 shark sightings reported to the GreatAustralian Shark Count had been in NSW.

Opposition industries spokesman Duncan Gay called on the NSW Government to immediately increase the quotas on fishing sharks.The small 60-tonne quota in NSW has already been reached for this financial year.

“Shark fishermen have been telling the state Government shark numbers are in plague proportions and the quota needs to be overhauled, but they are being ignored because Labor’s policy is dictated by the Greens preferences they rely on at election time,” he said.

“The state Government should lift the quota on shark fishing and reinstate funding for air patrols. It also needs to urgently look at more shark nets at swimming beaches.”

Michael Brown of Surfwatch Australia also blamed the Government. “These sharks are not here to cruise. They are here to eat,” he said. “The beaches need to be signposted and the Government needs to educate the public as to when the safest times are, and really make a point.”

Credit: Matthew Clayfield, John Stapleton, Additional reporting: Fred Pawle