Nick Vujicic, an Australian motivational speaker who was born without limbs, swims with sharks at the Marine Life Park in Singapore on Sep. 5, 2013. Reuters/Edgar Su

An 18-year old Australian was killed by a shark while spearfishing on the Great Barrier Reef, off the eastern tourist town of Port Douglas. Police said that the shark attacked Daniel Smith on his leg and arm, and he died to severe blood loss.

His friends, accompanying him on the private boat, called for emergency services and gave him first aid during the two-hour journey back to the shore. But, he could not be saved, ABC News, a local news network reported, adding that it was unclear what kind of shark attacked Smith who was fishing off the Rudder Reef.

Greg Thiedecke, executive operations manager at Queensland ambulance service, said that the teenager went into cardiac arrest immediately after he was attacked by the shark, and was likely to have died shortly after from severe blood loss, The Guardian reported.

“It would be speculating but (there are) a lot of large blood vessels in the groin area, so for him to go into cardiac arrest that quickly would be probably blood loss,” Thiedecke reportedly said.

Thiedecke claimed that such attacks were "very rare" in the region as he had not dealt with any shark attack during his 25 years of service.

Douglas Shire Mayor Julia Leu expressed sorrow for the family's loss. "Our hearts very much go out to his family," she said, according to ABC, adding: “It is a real shock to all of us that this has occurred. He had just completed year 12 at Mossman State High School - he was a lovely fellow and we are very, very sad that this has happened."

Over the last two years, shark attacks in Australia have claimed at least six lives. In September, a man died due to a shark attack at Byron Bay in the state of New South Wales on the country’s east coast. In February, another man was killed in a shark attack while spearfishing off the Goldsmith Beach, near Yorke Peninsula, toward Adelaide's west.