Surfing NSW announced Shimooka's death on its Instagram page.
"The team at Surfing NSW is deeply distressed at the passing of one of our own, John Shimooka, in the early hours of Monday morning,'' the statement said.
"A talented former world tour surfer, commentator and Jiu Jitsu black belt, 'Shmoo' was a much loved member of the global surfing community and the Surfing NSW family.
"He will be remembered for his passion for the lifestyle as well as his energy and enthusiasm.
"Everyone in our organisation joins his son, Brandon, immediate family, and his extended worldwide network of friends, in grieving his loss.
"It is our saddest day.
"We will commemorate and celebrate John's life in the days and weeks to come.''
American surfing great Kelly Slater posted an image of himself alongside a smiling Shimooka to his Instagram page.
"My heart's ripped out. I'm sorry, Shmoo," Slater wrote. "I thought we had this."
Australian surf legend Tom Carroll responded: "No sense. I thought so too. Shmoo RIP."
Four-time world champion Lisa Anderson posted: "I'm lost for words. Hope you are at peace."
Countless other professional surfers paid tribute to Shimooka on social media, including Mark Mathews, Ronnie Blakey and Cory Lopez.
