A 35-year-old diver died on Saturday after being bitten by a suspected 4.5-metre shark while spearfishing with his family near Michaelmas Island off Albany, Western Australia. Police said the man was brought ashore in a boat and met by paramedics, but he could not be revived.

The death put sharks back at the centre of concern in a part of the coast where families and divers had been in the water hours earlier. Emergency services were called to reports of a possible shark attack just before 11.30am Saturday AWST, and St John Ambulance said multiple crews remained at the scene later in the day treating the man.

Michaelmas Island sits off Albany, about 375 kilometres south-east of Perth, a stretch of coastline where a single incident can quickly force warnings, closures and questions about what is in the water. The state’s department of primary industries said the man was bitten near the island and warned people to take additional caution in the area, including following any beach closures advised by local park rangers or surf life savers.

The detail that remains unresolved is the one that matters most to many people heading out along the coast: the exact species was not identified, only that the shark was suspected to have been about 4.5 metres long. That uncertainty is part of what makes these incidents so stark. The threat is immediate, but the animal itself is often known only by size and by the damage it leaves behind.

Police said they would prepare a report for the coroner, a step that will help establish the formal record of what happened on the water that morning. For the man’s family, the emergency response ended in the worst possible way. For everyone else in the Michaelmas Island area, the warning is simpler: stay alert, respect closures and assume the coast is not the same place it was before Saturday.