Experts have identified that the mysterious shark caught two years ago by a local fisherman off Rottnest Island was a mandarin dogfish, a specie that's only usually found between Indonesia and Japan as well as in New Zealand.
A two-year investigation including DNA sequencing on the shark lead to the conclusion, Ryan Kempster, a shark biologist from the University of Western Australia's Oceans Institute, said.
There were actually two mandarin dogfish sharks, a male and female, roaming in the waters that time two years ago, according to Steve Downs, the recreational fisherman who saw them. The male was just under a metre long while the pregnant female was about 1.2 metres long.
"When I saw them, they had characteristics of many different sharks, but not all the characteristics of one species," said Mr Kempster, whose help Mr Downs sought because he failed to identify the species of the sharks.
It then turned out that the species had actually never been seen in Australian waters before.
What's more, in the conduct of their evaluation, Mr Kempster said a female mandarin dogfish normally only has up to 10 the maximum number of pups. Or so experts thought.
"The female shark found off Rottnest had 22 unborn pups and is only the second-ever recorded specimen of a pregnant female of this species," he said."Previously, it was thought that the maximum number of pups for this species was 10."
The experts still cannot offer any conclusive reason as to why the couple mandarin dogfish sharks were found far away from their normal habitat.
"While people talk about climate change and warmer waters affecting the populations of sharks, these sharks are found in the deep sea and therefore the temperatures down there would not have changed much in the past couple of hundred years," he said.