West Australian authorities insist a single great white shark was the likely attacker of 23-year-old surfer off Western Australia’s south coast, despite the victim saying he had been mauled by two bronze whalers.

Bunbury man Sean Pollard lost both hands and part of an arm in the attack near Wylie Bay at Kelpids Beach, about six kilometres east of Esperance, on Thursday morning.

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As he recovered after emergency surgery in Perth that night, reports emerged he had told one of the first people on the scene he had been bitten by two bronze whalers, describing it as a “feeding frenzy”.

The state’s Fisheries Department, which immediately responded to the attack by catching and killing two white sharks on drumlines, says he was more likely to have been mauled by that species.

It is the first time white sharks – a protected species – have been killed by WA officials.

The ABC reports that fisheries staff received abusive phone calls after the two sharks were caught and killed.

One staff member made a complaint to police and was concerned enough that she decided not to stay at her home on Friday night.

On Saturday, the department’s principal shark scientist Rory McAuley said Mr Pollard’s surfboard had been examined and indications were that a white shark was responsible for his injuries.

The analysis was inconclusive as sharks often disgorged stomach contents when they were caught, Dr McAuley said.

He explained the discrepancy between the victim’s account and their analysis as being down to white sharks sometimes having a bronze discolouration.

He said the first caught shark was 3.46 metres long, while the second was 2.68m.

Dr McAuley said the jaw measurements would help with future bite investigations.

“Our team has since collected samples from both sharks, including sections of vertebrae, which will assist us with our research work,” he said.

“Now that our investigation is complete, material will be made available to other research institutions.”

Beaches in the Wylie Bay area have been reopened after being closed since about midday on Thursday.

The department says there have been no new sightings of sharks in the area since the two white sharks were captured, but patrols continue.