Mike Psillakis shared an emotional tribute to his brother Mercury after the 57-year-old was fatally mauled by a shark at Long Reef Beach on Sydney's northern beaches.
"He was my mirror, my blood, my DNA," he wrote in a post on Instagram.
"We share the same soul.
"We had our own language and shared the same dreams."
His brother's energy could be felt in every corner, Mr Psillakis said, as he urged others to hold their loved ones tight.
The 57-year-old was alerting other surfers to the shark before he was attacked, Dee Why local and former pro surfer Toby Martin said.
"Unfortunately, he was the last one furthest out to sea and ultimately paid with his life," he told Nine's Today program.
"But it's important to recognise this is just a super rare incident.
"It's a beautiful place to be, the ocean ... it's a safe place."
The Long Reef Boardriders Association held a memorial for Mr Psillakis on Sunday evening, while Premier Chris Minns called him an "absolute hero" for trying to warn others about the shark.
Dee Why and Long Reef Beach have not reopened since Saturday's incident and Manly and Freshwater beaches were closed on Monday following an offshore shark detection.
The shark was last detected in June near Soldiers Beach on the Central Coast, having been tagged in 2023 at Coffs Harbour.
The weekend's fatal attack, the first recorded on the northern beaches in nine decades, has impacted shark safety net trials.
The nets, which only stretch 150m, are installed at beaches between Newcastle and Wollongong, including Dee Why throughout spring and summer.
Long Reef has no net, but smart drum lines are used to monitor for shark activity and were in the water when the shark attacked.
Nearby Dee Why Beach has a shark net approximately 500m out from its surf lifesaving club.
Animals could swim around and under the nets and they offered little protection, Macquarie University natural sciences professor Culum Brown said.
"You cannot tell the difference between unprovoked attacks on netted beaches versus other beaches," he told the ABC.
"If they do have any effect, it's largely psychological rather than providing any kind of protection."
A trial removal of three nets in the Central Coast, northern beaches and Waverley local government areas has been paused following the attack.
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