A shark sighting by a competitor at the infamous Southside break, Margaret River, Western Australia, has derailed the third day of competition at the Drug Aware Pro Margaret River presented by O'Neill.

Amee Donohoe (NSW) saw the shark as she was paddling back out to the line-up after catching a wave in the ninth heat of the morning's action. Donohoe, who was leading the heat at the time, saw what she described as a "massive fin and a wide girth" and quickly came in.

"I was paddling back out through the channel and saw this massive fin, it was really wide. I got a pretty good look at it – good enough to not want to stay in the water."

Currently rated fourth in the world, Donohoe alerted her fellow competitors and event organisers, signalling a swift end to competition.

"I've surfed all over the world with dolphins hundreds of times before and at places like Ballina on the East Coast, so I knew when I saw the fin it didn't belong to a dolphin," she said.

Locals have reported a spate of shark sightings in recent weeks. Allegedly feeding on the large abundance of salmon in the Margaret River area, today's sighting is not out of the ordinary, but is concerning nonetheless, both for competitors and event organisers.

ASP World Tour Head Judge, Perry Hatchett highlighted that the competitor's safety is the prime concern: "We have to adhere to the safety protocol which consists of keeping the water clear of all competitors," he said. "At this current point in time we have water patrol moving around the area making sure the competition area is clear and safe. From here we will meet again to make a judgement on whether the surfers will return to the water today based purely upon safety."

Based upon ASP rules, the heat will be re-started and all scores will still remain. As a matter of safety, jet skis will patrol the competition area to keep the situation under control and provide the surfers with a hasty escape from the water.

"As long as they are more content with salmon as opposed to the surfers I'll be happy," said Donohoe.