A man in his 50’s has been bitten by what is believed to be a bull shark in the Swan River at Blackwall Reach in Bicton this morning.

It’s understood Cameron Wrathall was swimming at about 8am this morning when he was attacked.

He was pulled from the water by people kayaking nearby, with the help of a stand-up paddleboarder.

Nine News reporter Lucy McLeod spoke with the kayakers at the scene this morning.

“They heard screams and that’s when they paddled over and saw a pool of blood in the water,” she said.

“They saw the swimmer struggling close to shore, he tried to drag himself to shore, he was with a friend at the time.”

The kayakers helped Mr Wrathall out of the water and provided first aid until emergency services arrived.

The man received serious injuries to his upper right leg and was taken to Royal Perth Hospital via ambulance.

He is now undergoing emergency surgery and is in a critical but stable condition.

The bull shark responsible for the attack is believed to be about two to three metres in size.

Swimming lessons were set to go ahead in the area this morning, but were relocated.

People are being advised to take additional caution in the area.

The last time someone was fatally attacked by a shark in the Swan River was 1923, and the most recent non-fatal attack was in 1973.

The area between Bicton Baths and Point Walter has now been closed.

Fisheries officers are conducting water and land based searches of the area, while WA Police and Surf Life Saving WA patrol the area from the air via helicopter.

Premier Mark McGowan says while the incident is unfortunate, not much can be done to prevent further attacks.

“We have tagging programs in the ocean obviously, we don’t have them in the river because it’s a different species of shark and we haven’t had an attack in 50 years.”

“Sharks migrate they move around, it’s very difficult to predict or prevent.”

If you see a shark, report it to Water Police on 9442 8600.

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(Photo: iStock by Getty Images.)