A WA fisherman has explained why he strapped a tiger shark to his bullbar to transport it home after the bizarre scene was captured on video.

The great grandfather told Seven News on Tuesday the shark was too heavy for him to lift into his boat.

“If I could have put it onto the boat or anywhere else, I would have done it,” he said.

“But as a last resort I put him on the bullbar. It wasn’t the fact of showing off.”

The man said the shark was already dead when he caught it and he hauled it in to avoid other sharks going after the carcass.

“If I put the shark back into the water, other sharks would come around and start a feeding frenzy and if people were nearby they could probably end up getting hurt or killed,” he said.

The man’s comments come after Department of Fisheries told media the fisherman could be hit with fines of more than $5000 if the shark proved to be protected.

Fisheries is investigating after a member of the public reported the catch and footage of the shark strapped to the car as it drove along Safety Bay Road on Monday was posted on social media.

The video has gone viral since it was posted on the Perth & WA Fishing Reports Facebook page on Monday.

On PerthNow’s Facebook page alone it has been shared by more than 1300 people and viewed more than 660,000 times.

Fisheries regional manager metropolitan region Tony Cappelluti said Fisheries officers identified the shark was a tiger shark from the images.

If the shark was found to be greater than a certain size, penalties would apply.

The Department is now trying to find the people involved so further inquiries could be made, he said.

“All whaler sharks, including tiger sharks, with an interdorsal fin length of 700mm or greater are recreationally protected, when taken from the South Coast and West Coast bioregions,” Mr Cappelluti said.

Camera Icon A video of this tiger shark being transported from Safety Bay has gone viral. Credit: Supplied

“Penalties for an individual committing a first offence include a fine of up to $5000 and an additional penalty of up to 10 times the value of the fish taken.”

Mr Cappelluti said Fisheries would need to physically measure the shark to determine whether it was protected so the Department had robust evidence for court.

He said an estimate from the footage might not be sufficient evidence.

“The transport method was the choice of the particular person involved,” he said.

“Obviously, in hindsight, driving around with a shark strapped to your bull bar is not a sensible thing to do.

“However, there is nothing in the Fisheries Act that prohibits that.

“Our advice to people would be to treat your fish well, be discrete about your activity and don’t bring attention to yourself.”

Mr Cappelluti said Fisheries officers had attended the Bent Street boat ramp in Safety Bay after a member of the public made a report but the people involved were no longer there.

WA Police have declined to comment on whether the driver will face a charge over his front licence plate being covered up.