An 11-year-old boy has escaped injury after a shark took a chunk out of his surfboard at a Sydney beach, less than 24 hours after a 13-year-old boy was critically hurt in a horror attack.

The Manly Observer reports the younger boy was kicked off his board while surfing at Dee Why, on Sydney’s northern beaches, when a shark lunged up at him on Monday.

Another surfer rushed to the 11-year-old’s aid as he screamed for help. The boy’s father, who had been paddling back out, reached him soon after.

Witnesses say they saw what looked like a bull shark of up to 1.5 metres in the water, although this is unconfirmed.

The Manly Observer posted a photo of the boy’s board with a clearly visible bite mark.

Monday’s incident came as police praised the heroic actions of three teenagers who likely saved the life of their mate, after he sustained critical injuries in a shark attack at Vaucluse, in Sydney’s east, on Sunday afternoon.

The 13-year-old boy remains in hospital with injuries to both his legs after being bitten by the shark at Vaucluse Point, a popular swimming spot.

He and his friends had been jumping from a six-metre rock into the ocean when the attack happened.

Superintendent Joseph McNulty said at least one of the boy’s friends jumped into the water and pulled him out after the attack, while the others called for emergency services.

“The actions of his mates who have gone into the water to pull him out have been nothing but brave,” he said.

“Those actions of those young men are brave under the circumstances and very confronting injuries for those boys to see, but I suppose that’s mateship.”

McNulty said the boy’s injuries were “very confronting”, and he was unconscious when pulled from the water.

Emergency services were on the scene quickly. Police officers applied two medical tourniquets to the injured boy’s legs before administering first aid on board a boat as he was rushed to waiting paramedics.

“As that police boat drove off at high-speed, they were still doing CPR on the boat hanging on, but keeping that boy alive at the time,” McNulty said.

“That boat had high-speed run across the bay into Rose Bay wharf where there was a waiting ambulance and paramedic team there for him.”

The teenager had surgery overnight and remained in a critical condition in intensive care at Randwick Children’s Hospital on Monday, where he was surrounded by family.

The Department of Primary Industries and Regional Development is working to identify the species of shark involved in the attack, with initial reports suggesting it was a bull shark.

The incident happened near Nielsen Park and Shark Beach, a popular swimming spot for families that has a netted area in Sydney Harbour.

McNulty believed extra fresh water in the harbour after the weekend’s heavy rain, combined with the splashing effect from people jumping off the rock face, had created a “perfect storm” for the shark attack.

“I would recommend not swimming in the harbour or our other river systems across NSW at this time … it’s not a good time to swim,” he said.

Multiple swimmers have been attacked by sharks in Sydney Harbour in recent years, including a young woman who was bitten on the leg at Elizabeth Bay in early 2024.

Avid surfer Mercury Psillakis, 57, died when he was attacked by a shark while swimming at Long Reef Beach on Sydney’s northern beaches in September.

Swiss tourist Olivia Mulheim, 25, was killed by a shark two months ago while swimming at a remote beach on the NSW mid-north coast.

-with AAP