State police said the 60-year-old woman was scuba diving with a man at a popular spot off Mindarie, north of Perth, yesterday when the shark attacked.
State police inspector Danny Mulligan said the woman’s 43-year-old dive partner managed to pull her out of the water after she was attacked, but her injuries proved fatal.
“The man said that he felt something go past him and he turned around,” Inspector Mulligan said. “He didn’t see the shark at that stage, but he felt it better to surface.”
When the man came up, he noticed “a commotion in the water”.
Three men who were fishing nearby in an 18ft boat rushed over to help the divers and spotted a shark that “was longer than their boat”.
They were able to pull the man out of the water but saw the woman had suffered severe injuries. The man managed to get back into his own boat and pull his diving partner onboard, but her wounds proved fatal, the inspector added.
The attack occurred just 20 minutes after surf rescue authorities in the area warned in a tweet that they had spotted a shark.
The woman is the second person killed by a shark in the region in the past few days.
On Tuesday, a surfer’s leg was bitten off by a great white shark in an incident about 60 miles further south.
Ben Gerring, 29, later died from his injuries.
His brother, Rick Gerring, has thanked the “heroes” who took him to shore and the staff at Royal Perth Hospital, where he died on Friday night.
Rick said the hospital’s care had given Ben’s family three days with him.
Rick said: “Obviously we were always hoping for the best outcome. It was always at the back of our minds that this could happen, but they gave us that time to say our goodbyes.”
Mr Gerring was attacked while paddling his surfboard at Falcon Beach in his home town of Mandurah, south of Perth. An inspection of his damaged surfboard showed a great white shark was responsible.
Fisheries Department representatives trapped and killed a large shark on Wednesday, but were unable to confirm whether it was the same creature that attacked Mr Gerring.
Area beaches have now reopened, but officials are warning people to be extra cautious in the water.
Since 2010, ten people have died in shark attacks off the Western Australia cost.