Shark expert's chilling prediction days before 12-year-old was mauled in Sydney Harbour: 'A snack for something like these'

A shark expert issued an eerie warning just days before a young boy was mauled by a suspected bull shark in Sydney Harbour, saying conditions were 'incredibly dangerous' and that an attack was becoming increasingly likely.

The 12-year-old boy was swimming with five friends at the western end of Nielsen Park in Sydney's eastern suburbs at about 4.20pm on Sunday.

Police believe he was jumping from a six-metre-high rock ledge known as Jump Rock, an area without shark nets, when he was attacked by a bull shark.

The boy remains in intensive care on Monday morning after suffering severe injuries to both legs.

Joel Nancarrow, owner of Hunter Shark Jaw Restoration, said heavy rain, murky water and river run-off had created what he described as 'perfect conditions' for sharks to move into crowded swimming areas.

He urged swimmers to stay well clear of dirty water, river mouths and low-visibility surf.

'We posted weeks ago that a child would be bitten this year, and yesterday we said this week is incredibly dangerous to be in the water,' Mr Nancarrow said.

'People who follow us know the dangers. Those that don't are probably none the wiser.

Days before the attack shark expert Joel Nancarrow (pictured) issued an eerie warning, saying heavy rain and murky water had created 'perfect conditions' for an attack 

Nancarrow said river run-off and low visibility were pushing sharks out of waterways and into crowded harbour swimming spots 

'We can almost predict these incidents now. If we can do this, why can't the science put stronger warnings out there?'

Mr Nancarrow said bull sharks were present in 'massive numbers' throughout Sydney Harbour and nearby waterways, driven closer to shore by recent rainfall.

He explained that muddy water reduces visibility and pushes large predators out of rivers and into beaches and harbour-side swimming spots in search of food.

'There will be a lot more big ones moving out of the rivers to feed along the beaches this week,' he said.

'They are aggressive predators with no limit to what they will bite. A 12-year-old child is a snack for something like these.'

Female bull sharks can give birth to up to 20 pups at a time, with hundreds entering the harbour system each season. 

Mr Nancarrow said the fast-growing juveniles quickly become dangerous as they mature.

He rejected calls for a shark cull, saying adult bull sharks were 'too smart' to be caught on government drumlines.

'The ship has sailed for a quick fix,' he said. 'It's all about awareness now.'

He claims bull sharks are present in 'massive numbers' throughout Sydney Harbour, driven closer to shore by recent rainfall 

He rejected calls for a shark cull, saying the animals are too smart to be caught, adding: 'The ship has sailed for a quick fix - it's all about awareness now'

While shark attacks remain rare, Mr Nancarrow warned they are becoming increasingly predictable, particularly during periods of heavy rain combined with warm water and crowded beaches.

Sydney Harbour has seen several chilling incidents in recent years.

In early 2024, a young woman was bitten on the leg at Elizabeth Bay.

In February 2022, British expat Simon Nellist was killed by a great white shark at Little Bay, Sydney's first fatal shark attack in six decades.

Before that, the city had not recorded a deadly mauling since 1963, when actress Marcia Hathaway was killed by a bull shark in shallow water at Middle Harbour.

More recently, veteran surfer Mercury Psillakis, 57, died after a great white attack at Long Reef Beach in September 2025. 

Two months later, Swiss tourist Olivia Mulheim, in her 20s, was fatally mauled by a bull shark at Kylies Beach in Crowdy Bay National Park.

According to the Australian Shark Incident Database, Australia has recorded 312 fatal shark attacks since 1791. 

Since 2000, 59 people have been killed, with almost half of those deaths occurring since 2020.