A Sydney couple was playing fetch with their dog at an off-leash beach in Sydney's south when she was taken by a 3.5-metre shark.
The American Staffordshire Terrier, believed to be a rescue dog named Molly, was pulled under while swimming at Bonna Point in Kurnell around 3pm on Sunday afternoon.
The Sutherland Shire Council on Monday issued a warning to swimmers and pet owners to stay away from waters near the area after Molly's owners alerted them to the attack.
The couple were "pretty traumatised" by the horrific incident, Fairfax Media reports.
"We were just throwing the stick in the water. The tide was really far out and there was a bit of a drop off (where the water became deeper)," Molly's owner Nigel said.
"It was very quick. It just took her under the water."
A council spokeswoman on Tuesday said lifeguards patrolled Kurnell beaches on Monday to warn people to keep out of the water.
Signs have also been installed to alert the public to the shark sighting.
"NSW Department of Primary Industries advises people to avoid swimming or surfing when it is dark or during twilight hours and encourages the use of the SharkSmart app which has safety tips for swimmers, surfers, divers, snorkellers and spearfishers," the council said in a statement.