"Can you imagine the public outcry, if anything else happened up there in that particular region during the holidays, if the department of fisheries took no action?" she asked media on Monday.



Four tiger sharks were dragged up by the drum lines over the weekend. On Monday a 3.7-metre-long tiger shark and a 1.2-metre-long blacktip whaler shark were caught.



Barwick's husband Craig issued a statement on Monday. "The reaction by the Queensland government setting drum lines and culling sharks is understandable and in some ways I appreciate it," he said.

“However, we have to understand that while there have been two attacks in rapid succession, shark attacks are rare and sharks play an important role in the ecosystem of the Great Barrier Reef.”



A drum line is a baited hook left in the ocean as a form of "shark control", the idea being that fewer sharks = less shark attacks. The system has been disputed in Australia by academics and environmentalists who say the lines could ruin the underwater ecosystem.

A shark's role as the top predator in an ecosystem is paramount to that ecosystem's maintenance. "They decide on whether other creatures become numerous or not," said Robert Day, associate professor and marine biologist in the School of BioSciences at the University of Melbourne.

“If there is a lack of sharks, then fish and other ocean creatures that would otherwise be consumed by sharks will become too numerous and eat too many smaller creatures and so on, meaning that the whole ecosystem changes massively.”



Green leader Richard Di Natale appeared on Sky News on Tuesday and called for the use of non-lethal shark deterrent technology.

"The reality is we don't know if the sharks that were killed were responsible for the attacks ... that's what swimming in the ocean means — that there are sharks present," he said.

"It isn't risk free and they do play a very critical role in our ecosystem."