Warming ocean temperatures are driving a rise in shark bites along Australia's coastlines, according to marine experts. The number of unprovoked incidents has increased from an average of 3.1 per year in the 1950s to 21 per year in the current decade, data from the Australian Shark Incident file shows.
Recent incidents heighten fear
Sydney's beaches have been particularly affected, with the latest attack occurring last Saturday when 34-year-old Leah Stewart suffered severe injuries from a suspected great white shark bite. Her arm was amputated, and she remains in intensive care. Rob Harcourt, a marine biologist and shark expert at Macquarie University, said many surfers are now avoiding the water. “A lot of my surfer friends are not going in,” he said. “A lot of people are very nervous – they’re traumatised.”
Warming oceans shift shark habitats
Harcourt explained that rising sea temperatures are causing bull sharks and tiger sharks to spend more time in the Sydney area. Bull sharks prefer warmer water, and tiger sharks also follow temperature gradients. Additionally, the recovery of seal and whale populations, which are food sources for larger sharks, may increase risk. “Swimming next to a seal colony probably puts you in greater risk,” Harcourt said, as sharks may mistake humans for prey.
Despite these factors, Harcourt noted that shark net data from the state government shows no significant change in shark numbers, contradicting claims of a population explosion. “If there were an explosion in shark numbers, then a lot more would also be caught in those nets,” he said.
Deaths and risk perception
Fatalities from shark bites have also risen, from an average of 1.7 per year in the 1950s to 3.8 per year so far this decade. Dr Daryl McPhee, a shark bite researcher at Bond University, said the trend aligns with public fear. “It’s consistent with what people are feeling,” he said. However, experts emphasize that the risk remains extremely low, with 82 drowning deaths at Australian beaches last year alone.
Public fear and control
Dr Brianna Le Busque, who studies public perceptions of sharks at Adelaide University, said comparisons to rare events like lightning strikes do not ease fear. “We talk about how rare bites are and that almost makes it feel even more random and that we have even less control,” she said. Her research found that surfers, despite higher exposure, fear sharks less than the general public, often describing encounters as “non-events.”
Management and controversy
Australia has used shark nets for over 80 years, but experts question their effectiveness. Prof Corey Bradshaw, an ecologist at Flinders University, called nets “an environmental catastrophe” with no evidence they reduce bites. He advocates for public education, drones, and personal deterrents instead. Calls for culls are also dismissed, as sharks are migratory. “It’s an old colonial view that we can bend nature to our will,” McPhee said.
