(CNN) Australian fisheries authorities have killed six sharks in the area of the Whitsunday Islands where two people were critically injured in shark attacks last week.

A 46-year-old woman and a 12 year-old girl were bitten in separate incidents within 24 hours of each other.

The attacks, on Wednesday and Thursday, occurred in Cid Harbour, a picturesque bay surrounded by beaches in a popular tourist area on the north coast of Queensland.

The Queensland Department of Agriculture and Fisheries said Monday that six sharks -- including a 3.7-meter (12-foot) tiger shark -- had been caught since three drum lines were temporarily deployed on Friday. Drum lines are a system of buoys "designed to remove larger, dangerous sharks from an area," a Fisheries Queensland spokesman said.

"As per the Fisheries Queensland protocol, the sharks were humanely euthanized, measured and taken out to sea for disposal," a Fisheries Queensland spokesman said in a statement.

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