A Perth father-of-two is in surgery after he was attacked by a suspected bull shark while swimming in the Swan River.
Cameron Wrathall, aged in his 50s, was attacked about 8am on Thursday at Blackwall Reach in Bicton.
Two kayakers helped bring him to shore and provided some first aid until emergency services arrived.
Mr Wrathall has a serious injury to his upper right leg and is having surgery at Royal Perth Hospital.
A spokeswoman said he was in a critical but stable condition.
Richard O’Brien was swimming with Mr Wrathall at the time and said it was “pretty horrific”.
“We were doing our usual swim and we were about to turn back, and the shark came up from below and bit Cameron,” he told 7 News.
David Davenport said he heard a shout and then he saw “the trail of blood coming out”.
One of the kayakers used their own shirt to try to stem the bleeding.
They said the wound appeared to be about 30cm long.
The Department of Primary Industries and Regional Development said the bull shark was reported as being between two and three metres long.
An area between Bicton Baths and Point Walter has been closed by the City of Melville.
The Town of Mosman Park rangers have also closed the beach area at Chidley Point on the opposite side of the river to Blackwall Reach.
Fisheries officers are conducting water and land-based patrols of the area, while helicopters from the WA Police Force and Surf Life Saving have conducted aerial sweeps.
Water Police have cleared people from the water.
People have been warned to take additional caution in the Bicton area and adhere to any closures advised by local government rangers.
The last time a person was killed by a shark in the Swan River was in 1923.
Premier Mark McGowan acknowledged the kayakers for rescuing Mr Wrathall.
“I’d like to thank them for that and I wish the man all the very best in a recovery,” he told reporters.
“I understand it’s quite a serious bite, but we all hope and wish for the very best for the man involved and hope he recovers fully.”
Mr McGowan described the attack as a “very, very surprising event” given there had not been a similar incident in the river for about 50 years.
“This is unexpected and surprising,” he said.
“It’s nothing, nothing that anyone expected would occur because it hasn’t happened for 50 years.
“It’s very difficult to predict or prevent.”
Mr McGowan said there was always a risk — even a tiny risk — when people entered the water.
Last year, sharks claimed the lives of three people in WA.
Gary Johnson was killed by a white shark while diving with his wife near Cull Island off Esperance in January.
Surfer Andrew Sharpe was mauled by a suspected white shark at Kelp Beds in Wylie Bay near Esperance in October.
Charles Cernobori was bodyboarding at Cable Beach in Broome when he was fatally attacked by a bull shark in November.