SYDNEY, Australia — An Australian diver who survived being half-swallowed head first by a great white shark said yesterday that being clamped between its massive jaws was like being trapped in a dark cave.

Describing his remarkable escape for the first time, Eric Nerhus said that as he desperately tried to scramble into a boat after fighting off the 12-foot man-eater, he feared that it would attack again and bite off his legs. He said he felt like “the luckiest man alive” after narrowly avoiding ending up as “fish food” during the terrifying attack on Tuesday.

Mr. Nerhus, a 41-year-old professional diver, recounted the details of his ordeal from his hospital bed in an interview for Australia’s Channel Nine television.

Heavily bandaged and with cuts, bruises, and a broken nose, he explained that he was searching for abalone, a prized shellfish, on the seabed when the great white came at him from out of the depths.

He was in about 30 feet of water off Cape Howe, a wild stretch of coastline near the border of New South Wales and Victoria.

One minute, he was searching for abalone, and the next, his head, torso, and one arm was enclosed by the killer shark’s razor-sharp teeth.

“I’ve never felt fear in my life like what I felt in the jaws of that white pointer,” Mr. Nerhus said.

“I went straight into its mouth, front onwards. Half my body was in its throat. It was like being in a dark cave.”