"The man and woman who was onboard have gone into the water in the late afternoon and they were taking turns at using a stand-up paddleboard".
After the attack the man was pulled aboard a nearby boat.
He was among fellow doctors and medical practitioners on the first of a five-day cruise in the Whitsundays on Monday evening when at about 5.35pm, while sharing a paddleboard with a female friend, he was attacked.
The victim was taken by helicopter to the Mackay Base Hospital, 100km to the south, where he died.
"CPR was ongoing for a very long time and every solid effort was made to save that man's life", O'Connell said, referring cardiopulmonary resuscitation.
A man has died following a shark attack in the Whitsunday Island's Cid Harbour, where two others were mauled in the space of 24 hours in September.
The victims were 12-year-old Melbourne girl Hannah Papps, who suffered a "significant leg injury" during the attack, and Tasmanian tourist 46-year-old Justine Barwick, who suffered severe injuries to her right thigh and had to undergo reconstructive surgery.
That attack had occured off Dent Island and 60-year-old tourist Patricia Trumbull survived lacerations to her buttocks and major blood loss.
Prof Colin Simpfendorfer, from James Cook University, said shark attacks were "extremely rare" in the Whitsundays, but no theories had "so far been supported by real substantial information" to understand the spike in shark activity. We simply do not know why this is occurring and what is responsible for it,"Gschwind said".
The species of sharks involved in the attacks have not yet been identified and Water Police and fishing boats were patrolling Cid Harbour on Tuesday, advising tourists on yachts to keep out of the water, O'Connell said.
All three attacks occurred in Cid Harbour, a picturesque bay surrounded by beaches in a popular tourist area on the north coast of Queensland. Critics argued that killing sharks was not the answer.