On 16 May 2026, Steven Mattaboni, a 38-year-old surveyor from Perth, Western Australia, died following a shark attack at Horseshoe Reef off Rottnest Island. The incident occurred at approximately 9:55 am while Mattaboni was participating in a members-only pelagic pairs spearfishing competition. He was at the surface of the water, roughly 20 metres from a nearby vessel, when he sustained severe injuries to both legs. Companions retrieved him from the water and transported him by boat to the Geordie Bay jetty, where they administered CPR. Paramedics attended the scene but were unable to revive him. A white shark measuring approximately four to five metres in length was reported in the vicinity at the time of the attack; the species was identified across multiple sources as Carcharodon carcharias.

Rottnest Island is situated approximately 18 kilometres off the coast of Perth in the Indian Ocean. Horseshoe Reef lies within the waters surrounding the island, an area frequented by recreational and competitive divers. Carcharodon carcharias, commonly known as the white shark or great white shark, is a large apex predator present in temperate and subtropical coastal waters around Australia. The incident was confirmed as fatal by emergency services. A fundraising campaign was subsequently established to provide financial support to Mattaboni's surviving family members.