Khai Cowley was fatally mauled by a suspected great white while surfing off remote Ethel Beach on the Yorke Peninsula, west of Adelaide, about 1.30pm on Thursday.
Emergency services rushed to the popular surfing spot in Innes National Park but were unable to save the 15-year-old's life.
Surfing SA says 15 year old Khai Cowley had 'a passion for surfing' and would be greatly missed. (HANDOUT/SUPPLIED)
Surfing SA paid tribute to the talented surfer "grom" from Maslin Beach in Adelaide's south.
"Khai was very involved in our surfing community with his passion for surfing stemming from a family with deep surfing roots in SA," the group said on Instagram.
"He was a happy, kind and respectful kid, very much loved by his surfing peers and he will be greatly missed out in our community and on the water."
View this post on Instagram A post shared by Surfing South Australia (@surfingsa)
Ryan Valente, a local skipper with Reef Encounters who knows the Marion Bay region well, said it was unusual to see great whites in the area and could not recall any similar incidents happening before.
"It's stuff nightmares are made of," he told ABC Radio on Friday.
"Yesterday itself conditions-wise was a very grim day - lightning, strong winds and it was quite a dark day.
"The town's in a bit of shock, I guess. Our hearts go out to the family that are involved in the tragic incident."
The SA surfer was thought to have been attacked by a great white shark. (AP PHOTO)
Andrew Fox, a researcher at the Rodney Fox Shark Museum, said great whites are ambush predators and murky conditions on Thursday may have increased their activity.
"They're more motivated - bigger swell, dirty water," he told ABC Radio.
"Anything that increases the chances of an ambush predator."
Khai's death rounds out a horror year for SA beachgoers, with three people killed by sharks and another two injured in the state's waters in 2023.
Teacher Simon Baccanello, 46, died in a suspected shark attack while surfing at Walkers Rock Beach, about 365km west of Adelaide, in May before 55-year-old Tod Gendle was killed surfing at Granites Beach on the state's west coast in October.
The bodies of neither man have been recovered.
Mr Fox said the recent uptick in shark attacks was a stark contrast to the relatively low amount of incidents during the previous eight years.
"These little clusters are more commonly seen in Western Australia and the eastern states," he said.
"We're known as a bit of a home to the great white shark. We know so much more about great white sharks but they're so mysterious still.
"A lot of surf places are also natural feeding grounds of sharks and there's been a lot of salmon seen swimming through that area in recent times."
A GoFundMe set up by Khai's family to help pay for his funeral costs had raised more than $36,000 by Friday afternoon - more than five times its target.