How Sydney’s beaches became a ‘perfect storm’

Shark researcher Chris Pepin-Neff said it was “extraordinary”: Four shark bites in 48 hoursthree of which are located within 15 kilometers of Australia’s east coast.

On January 18, a 12-year-old boy was sent to hospital with serious injuries and was later attacked and killed while swimming in Sydney Harbour. The next day, an 11-year-old’s surfboard was bitten at Dee Why beach, and hours later a man was attacked in nearby Manly and was taken to hospital in a critical condition.

Then, on January 20, a fourth surfer was bitten by a shark on his board about 300 kilometers (186 miles) from the coast, suffering “a chest injury.”

Pepin-Neff, associate professor of public policy at the University of Sydney, said: “This is the closest shark bite I have ever seen in 20 years of research, both in terms of distance and time.”

The rapidity of the incident sparked local and international panic, with dozens of beaches closed over fears of further attacks. Predictably, calls for shark culling are growing.

However, experts have warned against such measures, instead advocating for greater awareness of shark behavior and urging a rethinking of humans’ relationship with these fish.

They say a number of factors may have contributed to the recent series of incidents, but the problem is not with the sharks.

Unprovoked shark attacks are usually caused by environmental conditions, attractants in the water, or both.

The three recent incidents in Sydney – all believed to be related to bull sharks – followed days of heavy rain, with the city’s official weather station recording 127mm of downpour in 24 hours – the wettest January day in 38 years.

RMIT senior researcher Rebecca Oliver said the rainfall would create “perfect conditions” for bull sharks.

“Bull sharks thrive in warm salt water where most other sharks would flee,” she told the BBC. “They love estuaries and estuaries, so freshwater flooding from the land after recent rainfall events is perfect for them.”

Oliver and other experts further note that this fresh water may wash sewage and nutrients into the sea, attracting forage fish and, in turn, sharks.

“There’s clearly an attractant in the water,” Pepin-Neff said, suggesting a “perfect storm” of low-salinity freshwater could create a “biodiversity explosion.”

“Bait fish are surfacing, bull sharks are surfacing, everyone is in the inshore areas – now we have a problem.”

Official statistics show shark bites have gradually increased in Australia over the past 30 years – from about eight to 10 per year in the 2010s to an average of more than 20 per year in the 2010s.

But that doesn’t mean sharks are becoming more aggressive. More likely, the higher numbers reflect better data collection, as well as some complex human factors.

These include growth in coastal populations, an increase in water sports, and thicker wetsuits that allow swimmers to stay in the ocean longer.

“The total number of encounters is definitely much higher than it used to be because the number of people who get into the water and do all these things is really high,” Pepin-Neff explained.

However, they also noted that shark bite rates “are not as high as they should be because people are doing more in the water”.

Olive agrees, noting that “considering how many people use the ocean every day, incidents and attacks are relatively uncommon, and deaths even less common.”

If sharks appear to be becoming more prolific or dangerous, Oliver said, it may simply be because they are becoming more visible to community members — whether because of better reporting systems, the proliferation of drone footage, or excessive media attention to shark encounters.

Pepin-Neff added that broad, imprecise language around encounters can exacerbate fears and distort people’s understanding of risks.

When shark sightings, encounters and bites are lumped into the catch-all category of “attack,” the danger seems greater than it actually is.

“What happened cannot be meaningfully described without using the term ‘shark attack,'” they explained. “This creates a more emotional community experience that is slightly different than what actually happened.”

Concerns have grown after a recent spate of shark attacks in Sydney, reigniting calls for a cull of sharks. Typically this will involve using nets or baited drum lines near popular beaches to capture and kill sharks.

Experts rejected this suggestion.

“I can understand the calls for culling sharks in response (to attacks) … but I strongly oppose culling sharks so that we can maintain the illusion of safety when surfing or swimming in the ocean,” Oliver said.

At the same time, Pepin-Neff stressed that scientific research does not support that culling sharks is an effective way to reduce the risk of attacks.

“This just doesn’t work,” they said. “It makes politicians feel better, it makes activists feel better, and it makes it safer for anyone in the water.”

They added that in the case of shark encounters, the variable is not the sharks themselves but the attractants that attract them to the area.

“It doesn’t matter if you kill all the sharks in Sydney Harbor – if there are sharks on the coast and the attractant is still in the water, then the sharks are going to come in.”

Both Olive and Pepin-Neff believe the best way to reduce risk is to become more aware and vigilant of the factors that increase the likelihood of a shark encounter. On a personal level, this might mean avoiding swimming and surfing after heavy rain. For councils, this could mean building more shark enclosures where people can swim safely.

More broadly, however, they highlight the need for beachgoers to adopt a less idyllic, more pragmatic approach to the ocean.

“In Australia we have to treat our beaches like bush,” Pepinev said. “Australians know how to navigate the wild. We just need to emphasize that the ocean is still wild.”

They add that this will require rethinking not only our relationship with water, but also our relationship with sharks.

“This idea that the ocean is always safe but sharks are always dangerous – the opposite is true,” they said. “The ocean is never safe and sharks are not always dangerous.

“We’re in the way, not on the menu.”