LAKE MACQUARIE might be harbouring one of the rarest marine creatures found in Australian waters a Japanese devil ray.
The ray, which locals originally thought was a manta ray, has been in the lake for about a month.
It has become increasingly active in the past week and breached the lake surface many times on Saturday less than 100 metres off Wangi Point.
The creature's presence has drawn the attention of University of Queensland marine biologist and ray researcher Kathy Townsend.
Dr Townsend said that, based on the ray's description and location, she suspected it might be a Japanese devil ray, usually found in Indonesia and Japan.
Although manta and devil rays belong to the same family, devil rays have a shorter head and cephalic lobes, a white tip on their dorsal fin and a venomous barb.
Only 13 devil rays have been found in Australia, the first of which was caught in a net in Lake Macquarie on April 4, 1968.
"If this is a devil ray, it's a very significant discovery," Dr Townsend, who is also research manager at the Moreton Bay research station, said. "They normally don't travel that far south."
It is thought the ray sought refuge from large seas during a winter storm and was attracted to warm waters around Eraring power station's Myuna Bay outlet.
Coal Point resident Audry Diggins captured part of the ray's aerial display on video last Saturday.
"It was carrying on for quite a while," she said.
"When it came out of the water it was rolled up like a sushi roll and then suddenly spread out when it hit the water."
The ray was among diverse marine creatures, including a shark, a blue groper and turtles, presently in the area.
"We really need a proper study of what's in our lake so we can better understand what's going on," Ms Diggins said.