Explainer: Four people have died in shark attacks in Australia this year - should we be worried?

Explainer: A terrifying shark attack on a popular Sydney swimming beach has people asking, are shark attacks getting worse? And what's the reason behind them?

Shark attacks are still extremely rare in New Zealand, but we're just an ocean away from Australia, where a surge in fatalities and bites has raised fears and talk of culling.

Daryl McPhee is an associate professor at Bond University in Queensland who has done extensive research on unprovoked shark bites.

"A cluster of shark bites makes headlines for one simple reason: it frightens people," he notes.

But sharks aren't hunting us, and there are efforts to prevent attacks and better understand why these incidents happen. Here's what you need to know.

What's been happening with shark attacks?

There have been three deadly shark attacks in less than a month in Australia, as well as a woman swimming at a Sydney beach who was left fighting for her life in hospital after an attack last weekend.

"They do seem to be on the increase," Australian correspondent Nick Grimm told RNZ's Checkpoint this week.

Leah Stewart, 35, was attacked at the popular swimming beach Coogee in Sydney last weekend by what was believed to be a white shark, suffering critical injuries including the loss of an arm.

What shocked Australians about the incident is that it came in an unexpected area, and the victim was "doing everything right" to avoid attacks, Grimm said. She wasn't in a remote area, murky water or doing activities like spearfishing or surfing.

"She was swimming at one of Sydney's most popular beaches, not far from shore, and was attacked while inside the flagged area patrolled by lifesavers where swimmers are encouraged to enter the water and swim.

"All up, shark behavioural experts say she was incredibly unlucky."

The three earlier recent fatalities were all spearfishers in Western Australia and Queensland.

McPhee said the risk of bites to spearfishers is higher than for surfers and swimmers. Sharks can be attracted to dying fish and the blood and vibrations they make in the water.

In January, a 12-year-old boy died in hospital after a shark attack. At one point New South Wales saw four bite incidents in 48 hours.

Why are people being attacked? Is it happening more often?

Australia is a particular hotspot for shark attacks - more than half of the world's fatal attacks occurred there in 2025, according to the Florida Museum of Natural History's International Shark Attack database.

Twenty-three shark bite incidents and five fatalities were recorded in 2025 in an Australian Broadcasting Company analysis of the Australian Shark Incident Database.

While shark attacks grab our attention, McPhee noted that they do typically have some kind of pattern.

"These incidents align with a well-understood set of environmental conditions that occur periodically and predictably."

Some people think shark attacks become more common because the animals have been unable to find food - but that's not true, McPhee said.

"The commonest misconception is that sharks bite people because they are starving due to overfishing. In fact, the exact opposite is true."

Commercial fishing of Australian salmon has gone down compared to historic levels, while other coastal food resources like seals and whales are protected, which has a knock-on effect for hungry sharks, McPhee said.

"So it is an increase in the abundance of coastal food resources rather than a decline which may be resulting in white sharks spending more time in coastal waters."

New Zealand shark expert Riley Elliott told RNZ earlier this year that sharks are often trying to hunt in a poor visual environment, driven by many human impacts such as urbanisation, sedimentation and agriculture that lead to muddy harbours.

"Sharks don't [hunt] people," Elliott said. "Where they make mistakes is when they've been drawn into a food source, they're hungry, the visibility's poor and then people go in the mix."

Here in New Zealand, fatal shark attacks are less common but still happen.

Diver Jade Kahukore-Dixon was killed in an attack in the Chatham Islands in 2024 while 19-year-old Kaelah Marlow from Hamilton died in an attack in the Bay of Plenty in 2021 and Auckland filmmaker Adam Strange died in an attack off the West Auckland beach Muriwai in 2013.

Sometimes all it takes is one shark to cause alarm, such as a "rogue" great white suspected to be involved in a series of attacks in Dunedin between 1964 and 1971.

Are some people saying more sharks should be killed?

Former Australian Prime Minister Tony Abbott has repeatedly

called for a cull of sharks after the attacks this year, saying in a video to "put people before sharks." But others accuse him of trying to score political points.

"NSW already has a Shark Management Plan which has a lethal component for large target species and commercial and recreational fishers can already catch and retain sharks such as bull sharks," McPhee said.

Bull sharks aren't protected and one is believed responsible for the death of the 12-year-old boy in January.

But white sharks are "a nationally listed threatened species and cannot be retained by fishers," McPhee said.

"A directed cull after a bite occurs is a knee-jerk reaction and not likely to result in a change in risk."

Is climate change at all to blame?

One of the key drivers of shark attacks, especially bull sharks, is murky water after heavy rainfall.

"The strongest predictors of shark feeding behaviour are very heavy rainfall and warm ocean waters, both of which we've had in abundance," Macquarie University emeritus professor of marine ecology Rob Harcourt said in an interview earlier this year.

The 'climate driver' El Niño is predicted to be strong this year going into summer, and will lead to warmer, windier conditions. That could play a part in how many sharks come to our own waters.

"It is too early to predict whether the risk of a bite will change with El Niño conditions, but it is plausible," McPhee said.

"White sharks and bull sharks do respond to ocean temperatures and patterns of rainfall - either directly or through having their prey distributions change."

Is there any way to prevent shark attacks?

There are multiple measures in place to lower the risk in Australia, but most aren't commonly used in New Zealand.

Shark nets have been used in Australia but are controversial due to their effect on other marine life - and research has shown they aren't particularly good at reducing attacks, either. There are strict rules around their use in New Zealand.

Professor Culum Brown, head of the Fish Lab at Macquarie University, told the ABC recently that nets "don't really do anything, except give you a false sense of security".

Also in use are SMART drum lines, which consist of an anchor, two buoys and a satellite-linked GPS communications unit attached to a baited hook, which sends up an alert when a shark takes the bait. SMART drum lines are meant to be non-lethal, but older drum lines are not.

More than 3400 sharks were killed by nets and drum lines in Queensland waters last year, up from 1497 the year before, the ABC reported.

McPhee has said that Australia should move away from possibly lethal methods and more toward drones and less disruptive detection technologies.

Recent drone trials in Queensland found they spotted far more sharks than were caught in nets or drum lines.

"We now have the technology where we could have a drone on every major beach, if we wanted to," Brown told the ABC.

"We certainly need to spend more on that technology and getting rid of nets that don't do anything."

There are also a variety of "personal protection" shark deterrent devices on the market, although it's questionable how effective and reliable they actually are, the ABC reported.

Spearfishers like those killed in Western Australia face higher risk than surfers, as they're often bitten on the torso or head with no surfboard to partially block attacks.

For swimmers, if you're concerned about sharks the advice is always to go to patrolled beaches, stay close to shore and avoid swimming around dusk and dawn when shark activity is higher. It's also important to avoid areas used by fishers and not swim with pets.

Surf Lifesaving NZ also has guidance in place for dealing with shark sightings at beaches, including getting swimmers to leave the water immediately.

But McPhee and other shark experts warn against an overreaction to shark attacks, which are still overall extremely rare events, no matter how many headlines they generate.

"Shark bites are not contagious, and they are not spreading north or south like a weather system."

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