Beaches in Sydney, Australia, remained closed indefinitely on Tuesday after four shark attacks were reported in the state of New South Wales over a 48-hour period.

A surfer suffered minor leg injuries after a shark attack Tuesday morning on the NSW coast, several hundred kilometers north of Sydney.

In a separate attack on Monday evening, another surfer suffered serious injuries and went into cardiac arrest at Manly Beach in Sydney.

Earlier, a teenager was sent to intensive care following a shark attack inside Sydney Harbor on Sunday.

The sharks involved haven't yet been identified, but experts point to bull sharks as likely behind the attacks

What do we know about the latest shark attack in NSW?

In the latest attack on Tuesday morning, a surfer was knocked off his board by a shark in the state of New South Wales in Australia's east.

The surfer was "knocked off his board, his board has been bitten, there were multiple sharks in the water according to reports from other surfers in the water," Steven Pearce, the head of Surf Live Saving NSW, the peak body for water safety in the state, told Sydney's 2GB radio.

The attack took place at Point Plomer in Limeburners Creek National Park, about 450 kilometers (280 miles) north of Sydney. Point Plomer was "known for a bit of shark activity," Pierce added.

The man was taken to hospital "with minor injuries just to his leg," Pearce said. "I believe it's just grazes or minor cuts, so he's extremely fortunate."

This is the fourth shark attack on the NSW coast in 48 hours.

What do we know about Monday's shark attacks in Manly?

On Monday evening local time, a 27-year-old man suffered serious leg injuries after being bitten by a shark at North Steyne Beach in Manly in Sydney's Northern Beaches.

The surfer was pulled from the water by members of the public who commenced first aid before the arrival of emergency services, police said in a statement.

One eyewitness said another surfer had kept the man alive using his ‌surfboard's leg rope as a makeshift tourniquet to stem the bleeding.

"He ‌was breathing, ⁠but he was unconscious, and we just ... tried to keep him awake, as well as all the other people around us. Everyone was involved," the eyewitness told Australian ‍broadcaster ABC.

The surfer was suffering cardiac arrest and lost a significant amount of blood by the time paramedics arrived, NSW Ambulance Christie Marks said on Tuesday.

"The patient received 13 units of blood on the way to hospital," she said.

Local authorities closed a 30-kilometre stretch of coastline in Sydney on Tuesday and Wednesday following the Monday evening attack.

It's thought a bull shark was responsible for that attack.

Young surfer has lucky escape after shark bites board

Earlier on Monday, an 11-year-old boy escaped injury after a shark repeatedly bit his surf board off Dee Why beach, which is near Manly.

Pictures published by the Manly Observer show a chunk of about 15 centimeters (6 inches missing from the board. Several small bites are also visible on the board.

He walked away from the encounter on Monday morning unharmed, Surf Live Saving NSW said.

Witnesses say they saw what looked like a bull shark, possibly 1.2-1.5 meters (4 or 5-foot long), the Manly Observer reports.

Shark biologists at the NSW Department of Primary Industries and Regional Development said preliminary photo analysis of the bite mark suggested it was likely from a bull shark, the Manly Observer reported.

On Sunday afternoon, a 13-year-old boy was attacked near Shark Beach in Sydney Harbor and remains in intensive care with serious injuries to both legs.

Police said the boy was wading in shallow water after jumping off rocks with friends when he was attacked.

The marine area police commander said on Monday that police believe a bull shark was also behind that attack.

Why is Sydney seeing so many shark attacks right now?

Sydney and its surrounding coastline have been hit with substantial rain in the past few days.

This not only makes the water murky, it also results in raw sewage running straight into Sydney's harbor and coastline.

The nutrients in the sewage attract "bait fish and brings sharks toward the bait fish," University of Sydney associate professor of public policy Chris Pepin-Neff told the ABC.

The types of sharks involved in the string of attacks haven't yet been determined.

But bull sharks, which are one of the three sharks most frequently involved in serious shark bites in NSW (along with White Pointers and Tiger sharks), are particularly attracted to brackish, murky water.

The rain would have also flushed the sharks, which can also live in creeks and estuaries, into Sydney's harbor and its surrounding foreshore and beaches.

"We have such poor water quality that's really conducive to some bull shark activity," Pearce, the Surf Live Saving NSW chief, told reporters on Tuesday.

How many shark attacks are there normally in Australia?

Australia normally only sees around 20 shark incidents with injuries per year, with 2.8 fatalities annually in the same period.

So having three shark attacks with injuries just in NSW so early in the year is unprecedented. 

But swimmers are still more likely to drown on the country's beaches than be mauled by a shark, with Australia recording 82 such drowning fatalities in 2025.

Edited by: Zac Crellin