A sighting of an unusual looking shark near the Neptune Islands south of Port Lincoln has left scientists debating what caused it.
The photo of a shark with a hump on its back was taken on Sunday, June 16, when Perth-based ecologist Nathan Beerkens went on a tour with Calypso Star Charters.
He said he had been to the Eyre Peninsula a few times and had taken a keen interest in marine life as well as working on land mammals as part of his job.
"The crew had never seen that shark in the Neptune Islands before and they were quite excited and intrigued," he said.
I shared the photos to Twitter hoping for more information and got great responses from shark scientists from Australia and around the world.Nathan Beerkens
"I shared the photos to Twitter hoping for more information and got great responses from shark scientists from Australia and around the world."
Mr Beerkens said scientists' responses online provided insight about the shark's spinal deformity and that it could occur in whale sharks, grey nurse sharks and bull sharks too.
"Turns out this spinal deformity is rare but has been spotted in a whole range of sharks," Mr Beerkens said.
On Sunday June we saw 4 different Sharks including male shark who appeared to have a deformity. He had a very hunched back & a thin tail together with many scars. We do not know why he is like this and if we find our any further information we will pass it on #portlincolnpic.twitter.com/dIZSt3EWI3— Calypso Star Charters (@sharkcagediving) June 20, 2019
"It's been spotted in one other great white at the Neptune Islands but this new shark had a lot of different scars and was clearly a different animal."
Mr Beerkens said Macquarie University PhD researcher Connor Gervais replied to his Twitter thread and had been studying shark deformities.
He said Mr Gervais found that when Port Jackson sharks were reared in water temperatures just three degrees above normal, 18 per cent of them had a spinal deformity.
He said such a finding could have "scary" implication in future due to ocean temperature warming.
"Since our oceans are warming fast, this has scary implications for wild sharks," he said.
"We might start seeing a lot more deformed sharks in the future."
Other experts who commented on the picture suggested it was unusual though not unheard of in other species including teleost fish.
Flinders University associate professor and Southern Shark Ecology Group research leader Charlie Huveneers said another white shark in the same location also had a spinal deformity.
He said it had been regularly sighted there for more than 10 years and grey nurse sharks had also been sighted with similar deformities in South West Rocks, New South Wales.