CANBERRA, Australia -- A man used his surfboard to fend off a shark that bit him on his calf off an Australian beach two days after a fatal attack on the Great Barrier Reef.

Lee Jonsson, a 43-year-old teacher aide at a local school, was bitten Wednesday at Shelly Beach off Ballina in New South Wales state. Japanese surfer Tadashi Nakahara died at the same beach in 2015 after a great white shark 3 to 4 metres (10 to 13 feet) long tore off both his legs.

Government shark experts measured the tooth imprints in Jonsson's surfboard and concluded a juvenile great white shark 2.6 metres (9 feet) long was responsible.

Ballina Shire Mayor David Wright said Jonsson came onshore after he was bitten while lying on his board, wrapped his leg and went to the hospital for treatment of a 20-centimetre (8-inch) wound.

"It dragged him off and he fought the shark with his board," Wright said. "It's one of those unfortunate things."

Beaches in the area are expected to be closed for at least 24 hours.

On Monday, a shark killed a man in a harbour in the Whitsunday Islands, where two tourists were mauled in September. The islands are 1,300 kilometres (800 miles) north of Ballina.

The victim, 33-year-old doctor Daniel Christidis, had been diving from a paddle board while on a yacht cruise. Police Inspector Steve O'Connell said the group included other doctors who worked to save him but Christidis was injured too severely.

The spate of attacks in the Whitsundays has left authorities struggling to explain an apparent escalation in danger in the internationally renowned vacation destination. In September, two Australian tourists were mauled on consecutive days, one a 12-year-old girl who lost a leg.

Tourism Whitsundays general manager Natassia Wheeler said Christidis' group of 10 friends had been warned when they rented the yacht not to swim in the harbour where he was attacked.

The briefing by the rental company "involved saying no swimming at all in Cid Harbor, ... no swimming at dusk and dawn -- all of the standard safety procedures," Wheeler told Australian Broadcasting Corp.

Rescue helicopter crew member Ben McCauley, who accompanied all three Cid Harbor shark attack victims on the 100-kilometre (60-mile) flights from Cid Harbor to Mackay Base Hospital, said his role had taken a personal toll.

"It's tough. If you went home and came to work the next day and pretended it doesn't affect you, you're just lying to yourself," McCauley said.