"I just reached around with my other hand and I just pulled as hard as I could with both hands."
The shark let Croon go.
"I didn't know whether it bit my arm or my back or my leg I just didn't know," he said.
"And I just said to myself 'f... if you want to get out of this alive you need to calm down'."
Back on the surface, the 45-year-old discovered the shark had only bitten down on his backpack - it was ripped and torn.
Last week it was reported the smallest great white shark ever recorded in New Zealand had washed up on Ninety Mile Beach.
At 1.05m long, and 7.8kg in weight, the shark pup was something New Zealand scientists had not seen before.
Compared with fully grown great white sharks, which weigh up to 2000kg and measure up to 7m long, the shark really was a baby shark.
Scientists at Auckland Museum carried out a detailed necropsy on the shark.
Meanwhile, Croon told Stuff the shark attack was the second attack he'd survived, the first taking place in 1993.
"Every time I've seen a shark I sort of move down the coastline a bit and jump in", he said.
"It's like falling off a horse mate, if you don't get back on you may never do it again."
And while he loved his job, following the latest scare and at the request of his family, he said retirement was on his radar.
"I'm on the way out, put it that way."