A shocked fisherman has warned other anglers to watch out for a 4.5-metre Great White shark.
The recreational fisherman, who asked not to be named, was circled by the creature near the "community wreck".
"I leaned over and tried to touch its fin - why would you? - but I missed by a few centimetres," he said.
"I think it was a Great White."
The fisherman said the incident had happened about 2.30pm on Thursday while he was fishing for snapper at the "community wreck" or man-made tyre reef at Cockle Spit.
"It is not far out from Port Pirie and is about four or five kilometres away from where people go crabbing," he said.
"I have seen people and their kids go swimming around the crabbing area on the edge of the channel. It is something I would not do - it could be a disaster."
He contacted The Recorder to alert fishermen of the dangers.
"It is just a timely reminder with summer coming up," he said.
He said the shark had circled his boat and posed no danger to him.
"It looked majestic, actually, but if I fell in, I would have been gone straight away," he said.
"It was the change of tide. Everything was very quiet and I was wondering why and suddenly, 'Moby' turns up - I call him 'Shark Boy'.
"I have seen sharks before, but this is the one that hangs around the most.
"You could probably go out there for the next week and not see it, but it is there.
"With the snapper season now happening, it will be hanging around like a dog hanging around dog biscuits."