Bryn Martin, 64, went missing yesterday morning while swimming off Cottesloe Beach, and experts say damage to his recovered bathers are consistent with an attack by a 3m great white shark.
Mr Martin was a water sports enthusiast who loved his morning swim, his family said today.
Cottesloe Beach will be closed until at least Wednesday while police search for Mr Martin's remains.
Senior Sergeant Denise Grant said her concern today was not for swimmers using the closed beach but in returning Mr Martin home to his family.
After making his brief statement to the media, Mr Martin's son Alistair said the family had been overwhelmed by the rescue efforts to find his dad.
“We were talking about it last night as a family at the speed everyone was immobilised to get out there and try and find dad…its just fantastic,” he said.
“We are a pretty small family but we’ve got lots of friends and they have all rallied around (us)."
Alistair said his dad would venture into the waters at Cottesloe as part of a “daily exercise” routine.
“Even through it’s winter he would at least have a dip…he’s always been an avid diver," he said.
“He was aware of the risks, he knew what the risks were, he accepted them.”
His son also described his father's love of the water.
"Dad was always involved in water sports. He loved his morning swim.
"Yesterday we received news that any family would dread, and hopefully today will bring the closure we need."
He asked that the family's privacy be respected while they mourned their loss.
Bryn Martin was the chief executive of James Point, a company appointed by the State Government to build private port facilities in Kwinana.
A keen swimmer, he competed in the Rottnest Channel Swim and set the record for the oldest male duo swimmer in 2002.
Police this morning confirmed that the search for Mr Martin is no longer a rescue effort but a recovery operation, although police divers decided that conditions were to dangerous to go into the water today.
"It's very dangerous with the murky water," Senior Sergeant Denise Grant said. "The divers have made a risk assessment and decided that it's too dangerous to be diving today because the visibility is very low."
FATAL SHARK ATTACKS IN WA
September 4, 2011: Kyle Burden was killed while body boarding with friends at Bunker Bay, near Dunsborough, in Western Australia.
August 2010: Nicholas Edwards, 31, fatally mauled at Gracetown, near Margaret River.
December 2008: Port Kennedy fisherman Brian Guest, 51, taken by a giant white pointer while snorkelling for crabs in about 5m of water near his beachside home.
March 2005: A 6m white pointer killed boat skipper Geoffrey Brazier, 26, while he snorkelled off the Abrolhos Islands.
July 2004: Carpenter Brad Smith, 29, was attacked and killed by two sharks while surfing off Gracetown.
November 2000: Businessman Ken Crew, 48, was killed by a 4m white pointer in waist-deep water at North Cottesloe. In October 1997, Former St Kilda footballer Brian Sierakowski and friend Barney Hanrahan escaped injury when a 5m white pointer attacked their double surf-ski 150m off Cottesloe.
November 1925: Samuel Ettelton, 55, was fatally attacked by a tiger shark while floating on his back at Cottesloe Beach.
The 64-year-old father of two vanished while swimming out to a yellow buoy
off Cottesloe. Only his damaged Speedos have been found.
Experts say the damage is consistent with that of a shark attack.
Every Sunday at 8am on the dot, Mr Martin would head off with his "pod" on the coastal swim that was his weekly meditation.
Mr Martin's friends made the emotional swim without him this morning.
Fremantle Master's Swimming Club's Freo Fins group head coach Kim Tyler knew the family man for close to 15 years.
She said Mr Martin, a founding member of Freo Fins, was a "no-nonsense" friend with a heart of gold who would never want the group to give up swimming at Cottesloe.
The group were accompanied on their swim today by local sea rescue personnel in a lifeboat.
"We all swam out today, some of us swam to the groyne and back, we had a bit of a moment," she said.
"We all felt differently, worried, the visibility is zero, you can't even see your hand.
"We felt we needed to do it to overcome our own demons.
"It was very emotional."
She said ocean swimmers tried to mitigate the risks involved in their sport, by buddy swimming and only going out in safe conditions.
"(But) to some extent if you want to be an open water swimmer in WA, you understand the risks of swimming in the ocean," she said.
Mr Martin and the group often talked about the possibility of shark attacks, but the consensus was that sharks were a part of the environment and "you'd never see the shark that took you".
"The fact is they're out there, with swimmers, you're just swimming, you don't see them," she said.
Mrs Tyler said the group would host a proper memorial swim to honour Mr Martin when his family was ready.
She told Perth Now today's swim was a chance for the group to reflect.
Mrs Tyler said Mr Martin was so keen to get into the water every Sunday that stragglers were often left behind on the beach.
"Anyone who knows Bryn would sat he's a no fuss sort of guy, 'just get in there and do it' would be his motto," she said.
"He was a kind loyal man, a good strong swimmer and passionate about the ocean.
"He would do anything to help anyone else, he was a very kind man, a very solid person.
"He was very much at peace in the water, we all share that, people say we're mad, there's boats, sharks.
"If you want to be an ocean swimmer you've just got to be in the ocean, every day it's different, you get to see fish, you get to see the sky, the swell, the chop, every day it tests you in a different way.
"He loved it."