The guard at the time was unable to determine the species of shark and said it was too difficult to estimate just how big it was as it remained “several foot” under the surface of the water.

But Mr Anderson who has 20 years of diving experience in the area said it was almost certainly a bull shark.

He said there was an increase of sharks in our waters but said it was nothing unusual for this time of the year.

“It comes with this time of the year,” he said.

“We’ve noticed an increase in bait fish and sharks since about Boxing Day.”

But he said the only time a shark would come in contact with someone in the river was if they were doing the wrong thing.

“There’s very little chance of being bothered by a shark unless you’re doing the wrong thing at the time,” he said.

“The most important thing to remember is that we are not on their menu.

“It comes down to accidents, when people find themselves swimming in or near a bait ball and or swimming in dirty water.”

He said the best bet was to avoid the dirty water on the run out tides.