A hunt was underway Tuesday for a large shark that killed a Japanese surfer on Australia's east coast, as experts said fatal attacks remained rare despite three deaths in as many months.
Tadashi Nakahara, 41, died on Monday after a shark bit off both his legs at Shelly Beach, 187 kilometres (116 miles) south of Brisbane near Ballina.
"It came up behind and took his board and his legs and that's a horrible thing to happen," Ballina mayor David Wright said.
Witnesses estimated the animal was 3-4 metres (10-13 feet) long, possibly a great white shark, he said.
A New South Wales state government expert was heading to the area to help identify the shark, which has not been spotted since the attack. Local beaches remained closed.
It is the third shark killing in Australia since December when two teenagers died in separate attacks -- one on the country's west coast and one on the east.
Three other people are believed to have died from shark attacks in the past 12 months, while others have been injured including a surfer who lost part of both arms.
The latest fatality came a day after a surfer sustained injuries when he was bitten near Broken Head, just 30 kilometres from Ballina.
Shark expert Daniel Bucher from Southern Cross University said while there was no evidence of more sharks in the water, recent heavy rain in Ballina may have attracted them to river mouths in the hunt for food.
"It's more likely to be a just a chance thing," he told AFP.
"It's a very rare event, and rare events occasionally happen together and then there are long periods when they don't happen at all."
John West, a shark expert at Sydney's Taronga Zoo, said as the human population grew and more people chose to live near the coast, there was more chance of encountering a shark.
"However, there is no scientific evidence to demonstrate an increase in large free swimming shark populations in Australia," West said in an email.
"It is a rare event that a shark bites a person and in some cases a large shark will bite a person causing death."
West said shark attacks needed to be put into perspective.
"There are hundreds of people that drown while swimming in the ocean every year -- yet over the last 50 years there has been an average of one person killed a year," he said.