A fourth shark has been snared in drumlines off the Queensland coast in the wake of two life-threatening attacks in the Whitsundays.
The tiger shark was "humanely euthanised" after being caught in the Cid Harbour area on Sunday afternoon, Fisheries Queensland said in a statement.
"This shark measures 3.7 metres and, like the others, would pose a serious threat to people swimming in the Cid Harbour waters," a department spokesman said.
Fisheries Queensland has dropped the four baited hooks into the waters where Justine Barwick, 46, and Hannah Papps, 12, were bitten less than 24 hours apart last week.
The baiting and killing of sharks after the attacks won't prevent more attacks and gives swimmers a false sense of security, environmentalists said.
Sharks that were killed on Saturday. Source: Instagram: sailingpopeye
Human safety is paramount but the killing of four sharks in response to the attacks isn't the answer, according to animal rights groups.
"Public support for these shark control methods is dropping off," Humane Society International marine campaigner Lawrence Chlebeck said.
"We acknowledge the need for the use of technology and reducing these sorts of incidences ... but drumlines have been in the water since 1962, that's 60 years ago now.
"The technology is there and we've moved on."
The state government insists killing the sharks is in the interest of public safety despite admitting it will never know if they caused the injuries.
The Liberal National Party agrees it's the right move.
"I think the action that is being taken at the moment is appropriate, we need to find this killer shark," LNP deputy leader Tim Mander said on Sunday.
But Mr Chlebeck and Sea Shepherd's Jonathan Clark say personal shark deterrent devices, aerial spotters, drone surveys, public education and alert systems play a bigger role in preventing attacks.
"Stop the nonsense about speaking of 'effectiveness' only in terms of their ability to kill sharks," Mr Clark said.
"That bit is easy and it's lazy policy. Making beaches actually safer is much harder and unrelated to their ability to kill sharks."
Both victims in last week's attacks remain in hospitals in Brisbane.
Ms Barwick was last known to be in intensive care after 18 hours of reconstructive surgery to her mauled right leg.
Meanwhile, the family of Hannah Papps have expressed gratitude for the quick actions of those involved in her rescue.
"We would like to thank everyone who has helped and cared for Hannah, including the police, emergency services and the hospital teams," the family said in a statement on Friday.
"We ask that everyone, including the media, please respect our family's privacy during this very difficult time so we can focus our energies on Hannah's recovery."
