Shark control equipment had been temporarily placed in Cid Harbour following the first two attacks but was removed on September 27 after the potentially risky sharks were removed.
The 33-year-old victim was swimming with friends in Cid Harbour on the Whitsunday islands on Monday evening when the shark struck, leaving him with severe bites on his arms and legs.
"There's just a period of time when conditions are such that it maybe causes attacks to be more frequent".
Most of the victim's company were people with medical background, including two doctors, who brought him back to his yacht to seek help.
Ben McCauley, the emergency helicopter crew member, described the incident as "absolutely horrific".
In September a 12-year-old girl and a 46-year-old man suffered severe injuries from shark attacks while swimming on two consecutive days in the same area.
The pre-teen lost her leg in the attack, which led to a shark bait operation, in which six sharks were hooked and killed within a week.
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De hecho, sus compañeros habían iniciado una campaña solicitando dadores de sangre, pero su corazón no resistió. Pero el viernes se descompuso en su casa y fue trasladado inconsciente al Sanatorio Los Arcos.
That attack had occured off Dent Island and 60-year-old tourist Patricia Trumbull survived lacerations to her buttocks and major blood loss.
He died of his injuries, police confirmed early on Tuesday.
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.
Australia had not experienced a fatal shark attack since April 17 last year and its average of two deadly shark attacks per year that was recorded in recent decades has dropped. We simply do not know why this is occurring and what is responsible for it,"Gschwind said".
"The Cid Harbour area is not covered by the Queensland Government's Shark Control Program, which operates at 85 of Queensland's most popular beaches", he said.
Barwick's husband Craig said the measures were "understandable" and "appreciated" by his family, but the animals play an important role in the marine ecosystem.