By Olivia Henry, the Australian Science Media Centre

The tragic death of 57-year-old surfer, Mercury Psillakis, last week has reignited discussions about shark activity on Australian beaches.

The surfer, who suffered catastrophic injuries at Long Reef Beach in Sydney on Saturday, is believed to have been bitten by a 3.4-3.6 metre white shark, and has been hailed as a hero after alerting his friends to the shark nearby, saving their lives.

His family have called the situation a “tragic and unavoidable accident.”

As Mr Psillakis’ family and community mourn his loss, questions have turned to the incidence of shark attacks and what can be done to avoid such encounters.

Trials to remove shark nets from some NSW beaches have been suspended in response to the death.

Dr Brianna Le Busque from the University of South Australia told the AusSMC the trial pause is “unfortunate as shark nets are not an effective mitigation approach, and can actually provide ocean users with false security that they are being protected from bites.”

The recent encounter was the first fatal bite in NSW since 2022, she added, showing that shark bites, while tragic, are still rare.

“While this does not minimise how horrific it is when [fatal shark bites] occur, it is important we report the whole picture,” she added.

Dr Lucille Chapuis from La Trobe University agreed, adding that decades of research has not found nets and drumlines to be effective at preventing bites, and might even have the opposite effect.

“Nets and drumlines can also act as attractants, entangling sharks and other marine life, including turtles, dolphins, and rays. The science is still inconclusive as to whether they deter or increase risk,” she said.

The number of unprovoked shark bites fluctuate naturally from year to year, and experts say it’s difficult to predict whether risk on any given year will increase or decrease.

Associate Professor Charlie Huveneers said there are many factors that can contribute to shark bite risks, including “human population growth, habitat modification and destruction, declining water quality, climate change and anomalous weather patterns, and changes to the distribution and abundance of sharks and their prey”.

The rarity of shark bites also contributes to the difficulty experts have in determining which of the factors explain shark bites the most.

So what can be done? Experts recommend a combination of the three P’s: “Perimeter, Proximity, Prevent.”

“As a first line of defence, establishing an outer ring of measures to maximise the space and reduce overlap between water users and sharks,” Associate Professor Huveneers said, adding these Perimeters can be established through nets, but aerial surveillance, tagged shark listening stations and swimming enclosures are some other options.

The second is a personal line of defence when sharks cross this boundary, such as electronic deterrents that overwhelm sharks’ senses and reduce their likelihood of approaching and biting by up to 60%, even when sharks are in predatory mode.

The third P – Prevent – is to prevent bleeding and reduce injuries by wearing bite-resistant wetsuits, and know first aid for traumatic injuries.

Importantly, all of these factors rely on public knowledge, training and education, Associate Professor Huveneers said.

“Shark awareness is necessary to ensure that people know how to modify their behaviour to reduce personal risk, whether avoiding swimming/surfing at times of relatively higher risk, determining when to consider using a personal deterrent, or being able to respond to a shark bite quickly with suitable first aid.”

For now, experts continue to work to balance human safety while preserving such ecologically important animals.

“Sharks are vital top predators, and removing them indiscriminately can have significant ecological impacts," Dr Chapuis said.

“From a psychology perspective we know that people fear things that we feel we can't control, and non-effective mitigation techniques like nets can make people inaccurately feel in control of shark interactions,” Dr Le Busque added.

“We need to invest in other effective mitigation strategies and in continued shark science to better protect people, and the environment.”

You can read the full AusSMC Expert Reaction here.

This article originally appeared in Science Deadline, a weekly newsletter from the AusSMC. You are free to republish this story, in full, with appropriate credit.

Contact: Olivia Henry

Phone: +61 8 7120 8666

Email: info@smc.org.au