Tourists have been warned to keep out of the water in the Whitsunday Islands on Australia’s Great Barrier Reef after two swimmers were critically hurt in shark attacks on consecutive days.

A 46-year-old woman was mauled on Wednesday and a 12-year-old girl was attacked on Thursday while swimming from yachts in Cid Harbour on Whitsunday Island, the largest in the group of islands.

The victims were in critical but stable condition with leg wounds in hospitals in Brisbane.

The girl is from Melbourne and had been on holiday with her father and sister. The woman is from Tasmania.

Queensland Yacht Charter, which managed the victims’ boats, said tourists had been advised to refrain from swimming near the Whitsunday Islands for the foreseeable future.

Company managing director Tracey Whittaker said in a statement that the company was in shock and wished the injured swimmers the best in their recovery.

The Queensland government set baited drum lines in Cid Harbour to reduce local shark numbers.

“It is possible that there’s more than one shark involved in these unfortunate events,” Fisheries Queensland manager Jeff Krause told Australian Broadcasting Corp.

“We don’t normally go out and search for any sharks that may have been involved in a shark attack, but due to the nature of these multiple attacks, Fisheries Queensland is going to deploy three drum lines in a bid to try and catch some of the sharks in that area,” he added.

The islands attract various whaler shark species as well as bull and tiger sharks.

Bond University shark expert Daryl McPhee said that while the likelihood of being attacked by a shark is slim, the Great Barrier Reef has a higher population of sharks than other areas.