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January 25, 2026 — 5:30am
When the First Fleet sailed into Sydney Harbour in 1788, it abounded with marine life. Early settler journals recount sailors hauling in nets filled with hundreds of pounds of fish. One specimen weighed the equivalent of 150 kilograms and dwarfed those back home in Britain.
A teeming foodchain supported big apex predators. Diarist George Worgan, a surgeon on the First Fleet, reported “enormously large sharks that are very numerous”.
The astonishing video of a bull shark leaping from Sydney’s Parramatta River last week recalls these early colonial accounts.
Scientists say decades of environmental protections are taking effect and the ecosystem is becoming cleaner and healthier. The 2006 ban on commercial fishing in Sydney Harbour is also increasing fish stocks.
But four shark attacks in the past week have revived the debate over shark culls and netted beaches.
Experts who criticise these methods as false hope say the spate of attacks shows why Australia instead needs a shark danger rating system, like the fire danger rating systems used since the 1960s.
A clean break with pollution
There were 44 fatal shark attacks on Sydney’s beaches and in its harbour from 1788 until 1962. Since then, there have been just three, beginning with actress Marcia Hathaway, who was killed by a shark at Middle Harbour in 1963.
Sydney Harbour was known as a dirty waterway for nearly 200 years, with run-off from heavy industry and sewerage. But stricter environmental protections mean it is starting to clean up and marine life is returning.
A rare southern right whale delighted Sydneysiders when it entered the harbour in the winter of 1999. Now they are frequent visitors, sighted by tourists on whale watching cruises.
Swimming in Sydney Harbour also used to be less common. But Barangaroo’s Marrinawi Cove, which opened in 2023, shows that, as the harbour cleans up, more people than ever are swimming in it – and increasing the potential for shark encounters.
Global warming is also playing a part. Bull sharks, among the most dangerous for swimmers, now arrive in Sydney about a month earlier and stay a fortnight longer than they did 15 years ago due to rising ocean temperatures. The sharks prefer water that is above 22 degrees.
Since 1851, when records start on the Australian Shark-Incident Database, there have been 54 bull shark interactions in Sydney, as well as 25 with white sharks, three with whalers, three with tiger sharks, 33 with wobbegongs, and one with a grey nurse shark.
Professor Culum Brown, a shark expert at Macquarie University, told this masthead in November that the rise in swimming was a driving factor.
“It’s not the number of sharks that’s going up – it’s environmental changes and increases in the number of people who are engaging in water sports,” he said. “With climate change, you can swim off Sydney pretty much all year round now.”
Rating system ‘not that hard to do’
Greens senator Peter Whish-Wilson, a marine conservation campaigner, chaired Australia’s only parliamentary inquiry into shark management in 2017.
Since then, there have been three shark fatalities in Sydney: at Little Bay in 2022, at Dee Why in September, and from an attack in Vaucluse last weekend.
Whish-Wilson blamed the lack of action for a shark rating system on the reluctance of politicians to assume responsibility for the consequences of an ultimately uncontrollable natural phenomenon.
Like the fire danger system, shark ratings would have consistent standards nationally, with state agencies using their current monitoring systems to issue low, medium and high alerts in their jurisdictions.
Warnings would be based on factors that drive the likelihood of human-shark interactions, including water temperature, murkiness, rainfall, recent shark sightings and encounters, ocean currents, and the presence of bait fish close to shore.
“I don’t think it’d be that hard to do, and it’s exactly what we needed [for] warning people in Sydney last week,” said Whish-Wilson.
“As a surfer myself, and being a father of two surfers, I would certainly use a system like that.”
Sydney University Associate Professor Christopher Pepin-Neff has lobbied state and federal governments for more than a decade to implement a national warning system.
He said that while there was no guarantee people would adhere to warnings, such a system would at least enable them to make an educated choice.
“They can make informed decisions as beachgoers and surfers. What’s lacking now is the platform to provide that information,” Pepin-Neff said.
Federal Environment Minister Murray Watt said human safety was his priority and local authorities were best placed to provide shark danger warnings.
“Public safety messaging needs to be clear, consistent and communicated in a way that doesn’t confuse the community,” Watt said.
Last week, Sydney copped 127 millimetres of rain in 24 hours. This created a particular risk because bull sharks enter estuaries to hunt the smaller fish that congregate to feed after downpours. Pepin-Neff said Sydney should have had a high danger rating for at least three days after the rain.
Australian Marine Conservation Society shark scientist and shark campaigner Leonardo Guida said a warning system would be a useful safety measure, but must be designed with community input to generate buy-in.
“Bull sharks have lived in Sydney Harbour for millennia and a healthy Sydney Harbour, however that’s achieved, is really important for people’s work, play, and culture,” he said. “In order to coexist with a healthy harbour, we have to look at evidence-based measures that can improve safety.”
World Wide Fund for Nature (WWF) Australia head of oceans Richard Leck agreed there was “a lot of opportunity for Australia to develop much better systems to inform beachgoers in real time when conditions increase the risk of shark attacks”.
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