“It was having difficulty keeping its breathing hole above the water,” Peter Brown said of his heroics off Queensland’s North Stradbroke Island.

“I put on some goggles and grabbed my trusty kitchen knife,” he told the national broadcaster ABC.

Brown, whose wife stayed aboard their boat while he leaped to the rescue of the floundering whale, had called in trained whale rescuers but decided to act alone in a life-or-death situation.

Ronnie Ling, a volunteer with the Organisation for the Rescue and Research of Cetaceans in Australia said Brown was lucky to be alive.

“It’s really high risk, really dangerous stuff,” Ling said.

“When an animal’s in distress, when an animal’s entangled, they’re very unpredictable.

“They don’t see you as trying to help them. They just see you as a threat.”  Ling said there had not been an injury or fatality among the hundreds of Australians trained to disentangle whales, “but there was a chap in New Zealand who pushed his luck one too many times, and they never found his body. It’s simple: Never get in the water with a whale.”