Government shark experts measured the tooth imprints in Jonsson's surfboard and concluded a juvenile great white shark 2.6 meters (9 feet) long was responsible.
It's understood he suffered a 20cm wound as a result of the attack, in which he defended himself with his surfboard.
"It grabbed him on the leg and pulled him off the board".
The DPI earlier this year released findings from the second shark meshing trial, which found the majority of marine life caught in the nets were non-target species.
"It dragged him off and he fought the shark with his board", Mr Wright told AAP.
All beaches in the Ballina Shire have now been closed.
Shark nets at Shelly Beach and four others on the north coast were removed in May after a almost five-month NSW government trial.
"Daniel was a great surgeon, son, brother and friend, who dedicated his life to helping others", the Christidis family said in a statement.
"He said he tried to hit the shark with board".
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Cr Wright said he was unsure if the SMART drumlines were now out in the water.
"It's tough. If you went home and came to work the next day and pretended it doesn't affect you, you're just lying to yourself", McCauley said.
He was given immediate first aid from the group of doctors and medical practitioners he was with, and flown to Mackay Base Hospital in a critical condition.
Surf Life Saving New South Wales are asking people to stay out of the water and avoid the beach.
"Police and council have asked us to close the beach so our lifeguards are on site until DPI officers can investigate".
The attack follows a horror week on Australia's east coast, which has already seen the death of a 33-year-old man further north at the Whitsunday Islands.
On Monday, a shark killed a man in an island harbour in the Whitsunday Islands where two tourists were mauled in September.
Tasmanian woman Justine Barwick and 12-year-old Melbourne girl Hannah Papps survived after being bitten on consecutive days in September.
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