Four people have been attacked by sharks in New South Wales in 48 hours, including three incidents at Sydney beaches.
Any shark bite incident is traumatic and Sydney swimmers have been warned to stay out of the water.
So what are the details and why has there been so many bites in a short period of time?
What is going on with shark bites in New South Wales?
On Sunday afternoon, a 12-year-old boy was bitten by a shark near Nielsen Park in Sydney’s east while jumping off rocks with friends. The boy remained in hospital on Tuesday.
On Monday morning, a shark bit a chunk out of an 11-year-old boy’s surfboard. Later that evening at North Steyne, a male surfer was bitten and his injuries were said to be life-changing.
Further north on the state’s mid-north coast, a surfer escaped serious injury when he was bitten by a shark.
All Sydney’s northern beaches were closed and authorities said people should stay out of the water.
Dr Amy Smoothey, a fisheries scientist and shark expert at the NSW Department of Primary Industries and Regional Development, has analysed images of the bites.
She said bull sharks were responsible for all of them, as they have distinct broad and overlapping triangular “cutting teeth” in their upper jaw and more slender teeth in their lower jaw.
What are bull sharks and do they usually bite humans?
According to the Australian shark incident database, last updated in June 2025, bull sharks have been responsible for 212 recorded shark bites – or about 16% of all incidents – since records started in the early 19th century. They are responsible for a quarter of fatal bites.
Tiger sharks and wobbegong sharks are responsible for a similar number, with great white sharks cited in 382 incidents.
Smoothey said bull sharks can live for up to 50 years and prefer water temperatures above 19C.
They tend to arrive in Sydney in October with their numbers peaking in January and February before they leave around April or May on a 1,700 km journey north to Queensland’s warmer waters.
“There is no evidence that bull sharks are more aggressive than any other shark,” said Smoothey. “But it is their capabilities that exposes us to them.”
Sharks can detect movement in the water by changes in pressure and tiny electrical currents given off by other fish – an ability known as electroreception.
So low visibility is not a problem for a bull shark, said Dr Daryl McPhee, a shark bite expert at Bond University.
“They are well adapted to feeding in those murky waters.”
What’s behind this run of shark bites in Sydney?
One key factor behind the attacks starts with the intense rainfall seen in Sydney on the weekend, where some areas received more than 50mm in the space of a few hours.
This flushed large amounts of fresh and dirty water on to the coast and beaches, causing the water to go murky in some areas and making it an attractive spot for smaller fish to feed.
Rob Harcourt, an emeritus professor and expert in shark ecology and behaviour at Macquarie University, said the rainfall and time of year (bull sharks move to the Sydney area in summer) made it a “perfect storm” for the tragedies to unfold.
“For bull sharks, the likelihood of a bite is tightly linked to freshwater inflows, and that is no surprise if we understand their ecology,” he said.
As pups, bull sharks spend their first few years in estuaries before they move out into the ocean. That means they can tolerate freshwater and waters with lower salinity.
Observations of tagged bull sharks in the Sydney area show they move quickly to areas where there is turbid water.
“They move very quickly when the heavy rain comes to places where fish will likely move to. Fish will aggregate in those places,” he said.
Harcourt said it was likely the bull sharks responsible for the bites were in the area hunting for food.
Were the sharks hunting people?
The answer to this is very likely no. The bull sharks would have been hunting for smaller fish.
Harcourt said: “Some people will definitely be taken [by sharks] as prey. Others are probably investigatory bites, such as the surfboard that was bitten.”
What about long-term trends of shark bites in Australia and NSW?
McPhee says there is a long history of recorded shark bites in New South Wales going back to the early 19th century.
But he said there is a clear trend of increasing shark bites, particularly on surfers and particularly around Sydney’s northern beaches.
Between 1980 and 1994, NSW had just four bites recorded on surfers. But McPhee said this jumps to about 60 incidents between 2000 and 2019.
He said the likely drivers of those increases in bites was an increase in whale populations that meant more food for great white sharks, more people in the water, and a rise in ocean temperatures caused by global heating that meant bull sharks were in the Sydney area for longer than they used to be.
“Thankfully though, the risk of a shark bite is still very low,” said McPhee.
“We might think the risk is higher than it actually is because we have seen these three incidents in only about 24 hours. People can become highly fearful, but statistically the risk of a bite is low.”
How can people lower their risk of being bitten by sharks?
Around Australia, authorities have a common set of guidelines for swimmers to lower their risk of shark bites. They include:
Staying close to shore and swimming “between the flags” in patrolled areas.
Avoid swimming around dusk and dawn when shark activity is generally higher.
Stay away from areas used by recreational or commercial fishers.
Avoid swimming in river mouths, estuaries and murky waters and after heavy rainfall.
Swim with other people and don’t have your pets with you.
McPhee said it was an “urban myth” that the presence of dolphins meant there would not be sharks close by.
“Where you see a lot of activity, you will likely have sharks as part of that. It is best to avoid areas where birds are diving, where there are concentrations of fish and where there are dolphins,” he said.
