The United States was the leading country for shark attacks by far in 2015 with 59, followed by Australia (18) and South Africa (8)

A record of 98 shark attacks took place worldwide last year, the highest number ever recorded, a US university said Tuesday, citing warmer waters and more beachgoers as possible explanations.

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 of Florida, 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 by far with 59, followed by Australia (18) and South Africa (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 to venture further north and south, 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," 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," Burgess said.

Over the last five years, there have been seven shark-related deaths and 18 attacks there, which 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 by bears.