A record number of shark attacks took place worldwide last year, according to the University of Florida.

Warmer waters and more beachgoers are being cited as possible explanations for the 98 attacks.

However, only six of those attacks were fatal, which is the average number over the past decade, said George Burgess, director of the International Shark Attack File at the university, which has been collecting data since 1958.

"The number of attacks we had last year was the highest we've ever recorded," he told AFP.

But "your chances of dying last year in fact were less, because there were more attacks," he said.

The United States was the leading country for shark attacks by far with 59, followed by Australia on 18 and South Africa on 8.

Of the US attacks, 30 occurred in the southeastern state of Florida, while Hawaii saw the only shark-related death.

Increasing attacks could be due to rising water temperatures caused by climate change, which has led the sharks to venture further north and south, Mr Burgess said.

And last year, the El Nino weather pattern created warm ocean water, which always draws more humans to the beach.

"All put together with the fact that the human population continues to rise every year... one could predict that in theory each year we should have more attacks than the last," Mr Burgess said.

The previous record was set in 2000, with 88 attacks.

Of the six deaths in 2015, two occurred on the French island of Reunion, with one each in Australia, Egypt, New Caledonia and the United States.

"When people ask where is the most deadly place right now, it is Reunion," Mr Burgess said.

Over the last five years, there have been seven shark-related deaths and 18 attacks there, which Mr Burgess called an extremely high mortality rate.

Death by shark is a relatively rare occurrence, according to the International Shark Attack File, which reports that more people die from lightning, bike accidents and attacks by bears.