UPDATE: 3.15PM A surfer says he was menaced by a shark today off Trigg.
Ben Pobar was surfing at his regular spot, as he does every day he can, when he noted what he thought was seaweed in the surf.
He said he paddled over to investigate and saw a shark looking directly at him.
Mr Pobar has described how the shark eyeballed him for a few moments.
He said both he and the shark were frozen in place before the creature moved away and he started paddling back towards the shore.
He said he had no doubt that it was a shark and he feared that in a worst case scenario he would "have his legs munched off".
Mr Pobar said he had no reservations about returning to his favourite surf break tomorrow morning.
A Fisheries spokesman said that City of Stirling beach inspectors had been notified by a swimmer of a possible shark sighting.
When they investigated the claim they found no sign of a shark but that there had been a pod of dolphins in the area.
Surfers who had been in the area of the alleged sighting had told the inspectors they did not see a shark.
Surf Lifesaving WA and Water Police say they have not received reports of a shark sighting.