Hannah Papps, 12, was given life-saving first aid on a boat in Cid Harbour, off Whitsunday Island, and three pints of blood on the rescue helicopter flight to Mackay Base Hospital.

On Friday, she was transferred to Lady Cilento Children's Hospital in Brisbane in a critical but stable condition where she would receive specialist treatment for her leg wound.

Fisheries Queensland rolled out three baited drum lines on Friday in response to the attacks, told people in the area not to swim and increased patrol boats.

Bond University associate professor of environmental science Dr Daryl McPhee said there was "no easy solution" to these situations.

"I reviewed all of the shark deterrents for New South Wales a couple of years ago," he said.

"There was no easy solution, no off-the-shelf solution for all situations."

Dr McPhee said two shark attacks in 24 hours was unusual but not unheard of, and did not believe the same shark was responsible for both attacks.

"Most sharks eat a range of prey. They don’t get a taste for humans or anything like that," he said.

Great Barrier Reef Marine Park Authority assistant director of reef conservation action Mark Read said sharks generally did not hunt humans in the water.

"There certainly seems to be a variety of reasons why sharks interact with people in the water," he said.

"Territory is one, because they feel threatened and respond with a bite, and also sharks are curious animals and often check things out using their teeth.

"People often have strong opinions on the value of sharks.

"Sharks are a key component of the marine and estuarine regions.

"If you remove sharks, there will be considerable problems for the remaining species ... and they have very deep connections to the traditional owners."

Mr Read said baited drum lines were the right response to the attacks and swimmers should also take measures to reduce their risk of being bitten.

"People should not swim at dusk, in the morning, at night, in murky water or at the mouths of rivers, estuaries or creeks," he said.

The two victims were swimming off vessels they had rented from Queensland Yacht Charters when they were attacked.

"I have been in constant contact with both families and wish them the very best for the recovery of their loved ones," QYC managing director Christophe Vanek said.

"QYC continues to work with relevant government agencies in relation to both incidents.

"I echo Minister Furner’s statement that shark attack incidents are rare in the Whitsundays.

"Our staff and the broader community are feeling a great deal of shock.

"QYC has notified all current charter customers of the risk of sharks in Cid Harbour and advised against swimming in the region.

"For the foreseeable future, QYC charter customers will also be advised to be vigilant and refrain from swimming in Cid Harbour and the broader Whitsundays."

Children's Health Queensland confirmed on Friday evening that the second shark attack victim was 12-year-old Melbourne girl Hannah Papps.

"We would like to thank everyone who has helped and cared for Hannah, including the police, emergency services and the hospital teams," her family said in a statement.

"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."

Hannah was on holiday in the Whitsundays with her father and sister when she was bitten in Cid Harbour, off Whitsunday Island, on Thursday afternoon. RACQ CQ Rescue had originally advised media that the family was from New Zealand.

Hannah was airlifted to Mackay Base Hospital in a critical condition and transferred to Brisbane.

She was mauled less than 24 hours after Tasmanian tourist and avid snorkeller Justine Barwick was bitten by a shark in the same harbour.

Griffith University marine ecologist Johan Gustafson believed the two shark encounters were "test bites".

"Sharks can’t see, so they use their mouths. I think these were investigative bites," said Mr Gustafson, who has studied shark attacks.

"If the water is dirty, sharks can’t see people, so they are more likely to be chasing prey and a person just happens to be there.

"If a shark wanted to attack, we [humans] don’t come back from that."

- with Luke Sayer and AAP