Patrols continue at Blackwall Reach after swimmer attacked by suspected bull shark

Authorities continue to patrol Perth's Swan River for a second day after a shark attacked swimmer Cameron Wrathall on Thursday.

Cameron Wrathall was bitten on the leg by what is believed to be a bull shark in the Swan River.Credit: Facebook

Kayakers returned to the water at Blackwall Reach in Bicton on Friday morning, as Fisheries officers recommenced water and land patrols.

It follows Mr Wrathall being bitten on the thigh by a suspected bull shark while swimming in the river around 8am Thursday.

A Department of Primary Industries and Regional Development spokesman said drumlines would not be used to try and catch the shark that attacked Mr Wrathall due to the narrow section of river and high boat traffic.

"Drumlines would pose a dangerous public safety risk," he said.

The shark responsible for the incident is believed to be 2-3 metre bull shark.

"Bull sharks are attracted to freshwater rivers and estuaries to breed and based on scientific advice a relocation would not improve shark hazard risks," the spokesman said.

Kayakers return to the water near Blackwall Reach on Friday morning as Fisheries continue to patrol the area following a shark attack.Credit: Fran Rimrod

Mr Wrathall was rushed to Royal Perth Hospital after he was attacked by the shark and underwent emergency surgery.

On Thursday afternoon he remained in a critical but stable condition.

A nearby resident who witnessed the attack told WAtoday he heard screams coming from Blackwall Reach, in the southern riverfront suburb of Bicton, just before 8am.

He said kayakers paddled out to help Mr Wrathall, bringing him to shore with the help of a stand-up paddleboarder.

The man attacked by a shark in the Swan River on Thursday morning arrives at hospital. Credit: Nine News Perth

Bicton resident David Davenport was out on his deck overlooking the Swan River when he saw two swimmers splashing around near a boat.

"I thought, 'Someone’s jumped off the back', and then after a while the splashing stopped and they started swimming to shore and I could see the trail of blood coming out of the one guy," he said.

"I called my son and told him to come down here and I phoned the ambulance as they were swimming to shore."

Mr Davenport said seven or eight people carried Mr Wrathall, who is known among friends as a regular morning swimmer in the river.

Mr Davenport said he was astounded by the amount of blood which had come out of the swimmer but when he got down to the bank the rescuers had stemmed the bleeding.

"I was told they took his shirt off and used it as a tourniquet," he said.

Mr Davenport said he had time to think about whether his view on swimming in the river had changed.

Witness David Davenport. Credit: Peter De Kruijff

"It’s a risk you take every time, when was the last bull shark here? It was decades ago," he said.

Another witness said it looked like there was a lot of blood and a "good chunk" gone from the man's upper thigh.

Premier Mark McGowan described the incident as "very surprising".

A police boat is patrolling the river at the scene. Credit: Peter de Kruijff

"It's nothing anyone expected would occur because [a shark attack in the Swan River] hasn't happened in 50 years," he said.

"Some kayakers I understand rescued the man and I'd like to thank them for that.

"We all hope and wish for the very best for the man involved and hope he recovers fully."

The only recorded fatal bull shark attack in the Swan River happened in 1923, when a 13-year-old boy was bitten on the thigh while swimming near Mosman Park.

Blackwall Reach is the name of the limestone cliffs connecting Bicton's 'millionaire's row' – Blackwall Reach Parade – with Point Walter Reserve, about 10 kilometres from where the Swan River meets the ocean in Fremantle.

It encompasses the iconic Bicton Baths and Kent Street Jetty, and is an area popular with swimmers, kayakers and stand-up paddleboarders.

The area is also popular for cliff jumping.