A jumping shark has "photobombed" a surfing competition off an Australian beach.

Amateur photographer Steph Bellamy captured the image of the shark with her smartphone on Sunday as she was photographing mothers and their children paddling on their surfboards off a beach in the New South Wales state town of Coffs Harbour.

Bellamy, 47, said Tuesday that she did not know that the splash in her viewfinder was a shark until she examined the image on her phone moments later.

"He jumped twice, he photobombed big time, then he went on his way," Bellamy said.

The mothers, like Bellamy, had children in the Coffs Harbour Boardriders club and were taking part in a special mothers' heat toward the end of day of a local surfing competition when the shark appeared a few meters (yards) away from the group. She photographed the second breach.

Bellamy quickly showed the image to organizers, proving that the split-second disturbance had not been caused by a dolphin or tuna. The surfers were called out of the water. But about 15 minutes later, most returned and the completion continued, she said.

"Nobody was rattled. Everybody was really cool and blown away that I got the shot," Bellamy said.

Colin Simpfendorfer, a James Cook University shark expert, confirmed that the image was of a shark. He said it was possibly a spinner shark, which is common in the region and is known to jump from the water. He estimated it was around 2 meters (7 feet) long.

Lee Winkler, who was among the surfers near the shark, said he mistook it for a tuna.

"It was having a bit of fun," Winkler said. "It just jumped up and had a spin, then jumped up and had another spin, then went away."