Marine rescue volunteers say they are stunned a fisherman managed to survive six hours alone in the water off North West Cape near Exmouth, on Western Australia’s coast.

The man was fishing about 30 nautical miles offshore on Tuesday morning when he hooked a large marlin that pulled him into the water.

His boat continued on without him, leaving him stranded and treading water.

Another fisherman spotted his boat travelling at speed without a driver and alerted authorities.

He was found by a passing boat about six hours later.

He was taken to hospital back on the mainland suffering from severe hypothermia and shock.

The commander of the Exmouth Volunteer Marine Rescue Group, Rusty Ellis, said the man, who is believed to be in his 20s, was incredibly lucky to be alive.

“You’re talking about a microscopic pin dot in the middle of nowhere,” Mr Ellis said.

“For somebody to find him in time was a wonderful thing and I’m very very grateful for the assistance of everybody, for dropping everything they were doing.”

Mr Ellis says the incident serves as a warning to people about the dangers of fishing alone.

“They need to be extra careful in what they do at sea,” he said.

“It’s a very lonely place out there, and if you end up in the drink for whatever reason and you can’t do anything about getting back to your motorboat, it can be very painful for a lot of people.”

– ABC