A close friend of a Perth father killed in a shark attack off Rottnest Island says there was “absolutely no warning” before the experienced spearfisher was bitten while diving with friends.

Steven Mattaboni, 38, was attacked while spearfishing, something his best mate of more than 30 years said he had done thousands of times before.

“There was absolutely no warning for Steven,” Liam Thomas said.

“There was absolutely no signs of danger.”

Mr Mattaboni was with three friends about a kilometre offshore at Horseshoe Reef on Saturday morning when he was bitten on his legs by a large shark.

Those same friends who witnessed the incident pulled him from the water onto their boat, performing CPR on the way back to shore before paramedics took over.

Mr Thomas, who was not on the boat, spoke to reporters on Friday and thanked rescue teams on the island, who he said did everything they could.

“They gave Steve every chance possible, and we would like to extend just our absolute thanks and gratitude for everyone that supported Steven on the day,” he said.

“It’s really, really important for us to disconnect Steven from what took place last Saturday.”

Greatest love was family

Mr Thomas said his friend’s first love was the ocean.

“His second love and his greatest love was his family. And he was just so proud of his two beautiful daughters and everything that he did for them and everything he worked for was for them,” he said.

Mr Thomas said he’d been overwhelmed by the generosity and support of West Australians in the week since the attack.

An online fundraiser for Mr Mattaboni’s family has raised hundreds of thousands of dollars.

He had a long history with the Bluewater Freedivers club and he served in many capacities, most recently as club secretary.

“The reason why we loved him was because he had all these amazing attributes and values,” Mr Thomas said.

“He was charismatic funny, hardworking and had so many wonderful qualities that just made him so loved by so many.”

“Right now we are taking it day by day. We are absolutely heartbroken, but we’re here for the girls and we’re here for his beautiful wife Shirene and everything that we do from here is to support his beautiful family.”