A shark fatally mauled a diver off an Australian tourist island on Saturday, police said, marking the country's second fatal shark attack so far this year.

The 38-year-old man had been spearfishing with friends when he was attacked on a coral reef off Rottnest Island near Australia's southwest coast, Western Australia Police Sergeant Michael Wear said.

"The friends have witnessed the horrific event," Wear said.

The victim was near a dive boat when he was bitten on the legs, Wear said. He was then taken by that boat 1,100 yards to the island, where paramedics could not resuscitate him.

Lifeguards reported a 16-foot white shark had been seen in the vicinity before the attack, and the state's Department of Primary Industries and Regional Development told AFP the man had been bitten by a great white.

Officials did not name the victim but he was identified as Steven Mattaboni by family members, the Australian Broadcasting Corporation reported.

Mattaboni's wife, Shirene, said the family's "hearts are irrevocably broken." 

"Steven was a devoted father to our two beautiful daughters — one who turns three next month and our four-month-old baby," she said in a statement.

In a social media post, Western Australia Premier Roger Cook called the shark attack "deeply distressing" and thanked first responders and emergency personnel for their efforts. 

"It is a devastating time for all involved," Cook said.

The attack was Australia's first shark fatality since January, when a 12-year-old boy died in a hospital days after he was mauled by a bull shark in Sydney Harbor. The attack that killed the boy was one of four recorded in the span of two days, which prompted officials to close dozens of the city's beaches. 

In November, a shark killed a woman and seriously wounded a man at a national park beach on Australia's east coast in a rare instance of the predator attacking two people.

Rottnest Island's last fatal shark attack was in 2011, in which a 32-year-old diver died.

Australia has averaged more than three fatal shark attacks a year in recent decades.

There have been nearly 1,300 shark incidents around Australia since 1791, of which more than 260 resulted in death, according to a database of the predators' encounters with humans.

Australian scientists believe increasingly crowded waters and rising ocean temperatures are swaying sharks' migratory patterns, which may be contributing to a rise in attacks.