A Perth man has issued a warning for those diving for crays off Rottnest Island after his boat was circled by four large sharks early on Wednesday morning.
Rohan Lewis told 9 News Perth he had been on an inflatable boat off the coast of the popular tourist island when he saw a large shark approach his boat.
Soon, the shark was joined by three others - all equal in size to the first.
Mr Lewis said in his 30-years fishing off the island, he had never seen anything like it.
"Four sharks that size - when they're two thirds the size of your boat and you're in a blow-up boat - it's time to get out of there," he said.
"We threw the boat in gear to move away from them and we put the boat into a tight turn just to see where they were and they were definitely following us.
"I think if you'd been in the water this morning with four sharks around, one is curiousity but four's a pack."
The Surf Life Saving chopper hovered over Mr Lewis' boat to alert other water-users about the sharks, and an official alert about the run-in was posted to their social media as a formal sighting.
"If you're going to go diving for crays, I probably wouldn't do it anymore," Mr Lewis said.
A number of beaches along the island were closed as a result of the sighting.