What lurks in the depths at Boyne Island?

The rumour mill is rolling today following amateur footage of a mystery sea creature.

Boyne Island man Philip Lindfield says he has been left perplexed as to what the sea creature was he photographed in the Boyne River on Tuesday morning. Photo: Philip Lindfield

A BOYNE ISLAND man's sighting of an unidentified sea creature has left the community mystified as to what it could be.

Philip Lindfield said he was curious right away as to what was swimming through the section of Boyne River on Tuesday, which runs adjacent to his house.

"My first reaction was that it was a baby crocodile the way the tail was going to and fro but when I got closer I saw it had the one fin type thing," he said.

"I thought 'oh gee what is it?'"

Mr Lindfield said his post to an open discussion page on Facebook had been attracting attention all morning on Tuesday, as residents took guesses as to what the creature could be. Photo: Philip Linfield.

The Boyne Island - Tannum Sands rumour mill has already started turning, with several members of the community weighing in online.

"The comments are coming through, most of them thinking it is a baby shark which has been hit, catfish is another one which is not mentioned on those things," Mr Lindfield said.

He said he was not the only one with amateur footage of the creature - a lady there with him also took photos.

"She said she had once seen a big catfish under the bridge once, so that might be what the creature we saw this morning was," Mr Lindfield said.

"Just after the film was made this morning we both heard a big splash, it was either chasing something or jumped, we both heard and saw the splash but didn't see the fish."

Mr Lindfield said having only lived here since February, it was the first time he had seen anything like that.

"You see turtles at times and you know I saw the fin first up and thought it could have been a turtle, but the waving of the fin and tail meant it couldn't have been.

"It is just strange that it was sort of going along on the surface, stayed on the surface, to me it was strange."

The senior media and communication officer at the Department of Agriculture and Fisheries, Dianne Bye, said they could not comment as the photo's resolution was not clear enough.