Mr Anderson, the head coach at Bondi Fit, said he and his squad had gone out for a swim off Bondi about two weeks ago when they decided to check out the shark nets, which stretch across the bay. "There has been a lot of shark mania at the moment, so I wanted to take my swimmers out to the shark nets to show that they are real and they are there and they stop sharks coming in," Mr Anderson said. When they reached the nets, the group dived down between five and 10 metres and, as Mr Anderson was returning to the surface, he snapped a few photographs on his GoPro camera, which he usually takes on his fitness outings. No one in the group was aware of their close encounter with the shark until the proof emerged in the photograph, Mr Anderson said.

"I was coming back up and you can actually see, I was aiming back up towards the sun, and the shark was on my left and I didn't see it until I downloaded the photos," he said. Mark McGrouther, from the Australian Museum, said it was extremely hard to identify the type of shark from the photograph. The long pectoral fin would suggest it was a blue shark, but the body was too robust, he said. The large dorsal fin indicated that it could be a great white shark, while there was an outside chance it could be an oceanic whitetip shark, he said. "I can't be too sure," Mr McGrouther said.

"Seeing as how this shark was photographed on the inside of the net, it just shows you what we have known all along: that nets do not always prevent sharks from coming into the vicinity of the coast." Mr Anderson said he posted the photograph on Instagram after carefully considering what the reaction would be. He said his experienced swimmers were "pretty cool" about the incident. "I've got two distinct groups: the experienced, hard-core ocean swimmers and the rookie swimmers. My experienced group don't seem to care that much ... because they're kind of accepting," he said. "I think there is a little bit of a placebo living in the Sydney area, with people behind shark nets. They've got a false sense of security." Mr Anderson, who spends a lot of his time in the water, said that, since the photograph was taken, he had seen another shark while he was stand-up paddle boarding off Clovelly.

"For me personally, it's like 'Wow, this is close,' but I've actually seen a lot of sharks. I'm a little bit more neutral about it," he said.