The shark that ripped a boy from a fishing boat in north west Tasmania has been identified as a great white measuring more than three-and-a-half metres.
Lucas Arnott, 10, is recovering after the attack about five kilometres off the coast of Stanley on July 17.
He was standing on the side of the boat when the shark dragged him into the water.
His dad, John, jumped in and scared the shark away.
CSIRO scientists who examined Lucas's life jacket have determined the damage is consistent with a great white shark measuring 3.6 to 3.7 metres, the Arnott family said in a statement issued by police on Tuesday.
"Whilst this has been an extraordinary event, it highlights the importance of wearing a well-maintained and correctly fitted life jacket," the statement said.
"That, combined with the bravery of his father, helped save the boy's life."
Lucas spent several days in hospital after undergoing surgery for cuts to his arm, chest and head.
The Arnott family has asked for privacy after the attack, which attracted national headlines.
"This has been a traumatic event for the boy and his family, and they are thankful for the continued privacy they are being afforded to enable their son to fully recover," the statement said.
Bystanders in Stanley, which has a population of a few hundred people, gave Lucas first aid on shore before paramedics arrived.
His grandfather David has previously thanked those in the town for providing help.
"As you can understand, it was a shock to our family. It's taken us a while to digest what has happened," he said.
Australian Associated Press