An Australian swimmer who was mauled by a 16-foot shark and survived said Sunday he saw a shadow in the water seconds before the attack and thought it was a dolphin.

The shark, believed to be a great white, seized Jason Cull by the left leg as he was swimming at Middleton Beach in southwestern Australia on Saturday.

Cull, 37, survived after grappling with the beast and after a lifeguard at the beach came to his aid.

The shark was one of three that swimmers reported seeing at the beach Saturday. Officials closed the beach after the attack.

From his hospital bed where he was treated for deep lacerations, Cull told reporters he saw a shadow moving in the water just before the attack and mistook it for a dolphin.

"It was much bigger than a dolphin when it came up," Cull told reporters. "It banged straight into me — I realized what it was, it was a shark.

"I sort of punched it, and it grabbed me by the leg and dragged me under the water," he said. "I just remember being dragged backwards underwater. I felt along it, I found its eye and I poked it in the eye, and that's when it let go."

Tom Marron, a spokesman for the lifeguards at the beach, said volunteer lifesaver Joanne Lucas leapt into the water to help Cull after swimmers at the beach started panicking when they Cull struggling.

"She heard the cries and splashing and knew they needed assistance and just went straight in," Marron said.

"She got hold of the injured swimmer and brought him back to shore," he said. "There was a fairly comprehensive mauling of his left leg, lost a lot of his calf, severe lacerations."

Cull was in stable condition after having surgery at a hospital in Albany, about 250 miles south of Perth, the capital of Western Australia state, a hospital spokesman said on customary condition of anonymity.

Marron said people at the beach noticed three sharks Saturday and estimated their size at up to 16 feet.

There about 15 shark attacks a year in Australian waters — one of the highest rates in the world — but on average just over one attack per year is fatal.

Last month, a shark attacked and killed a 16-year-old surfer off Australia's eastern coast.