ORLANDO, FLORIDA –

Sharks attacked people 98 times in 2015, a spike in unprovoked attacks that set a new record as human and shark populations rise, researchers found in an annual global tally released on Monday.

Six people were killed by sharks, including a snorkeler in Hawaii. Two deaths were recorded off the Indian Ocean island of Reunion, and shark attack victims also died in Australia, Egypt and New Caledonia, according to data submitted by scientists worldwide.

While last year saw twice as many fatal attacks as 2014, the number of deadly encounters was roughly on par with the past decade's average, said George Burgess, director of the International Shark Attack File. Maintained at the University of Florida, the database was established in 1958.

The 98 unprovoked attacks surpassed by 10 the previous high recorded in 2000, he said. The rise reflects growing populations of both people and sharks, he said.

Shark attacks are occurring further north in the United States as warmer ocean temperatures extend the marine mammal's range, Burgess noted. In a rare incident, a New Yorker was attacked while boogie boarding off Long Island, he said.

"We're going to be seeing more bites north of Virginia in the east and California in the west in the years ahead as long as this warming trend continues," Burgess said.

Unseasonable warm water off the coasts of North and South Carolina likely contributed to 16 attacks there last year, including rare attacks in which two children were bitten in separate incidents less than an hour apart, he said.

Florida saw 30 shark attacks in 2015, roughly half of the 59 recorded in the United States, as is typical, Burgess said.

Hawaii saw seven attacks, and the rest occurred in California, Texas, Mississippi and New York. After the United States, Australia and South Africa recorded the next highest number of attacks, at 18 and eight, respectively.