The angel shark, a large flat species which resembles a stingray, is listed as critically endangered and was previously only reliably spotted around the Canary Islands.
But after a six month project led by the Zoological Society of London (ZSL) and Natural Resources Wales, evidence has emerged which suggests the angel shark is living in UK waters.
A series of sightings by fishermen in Cardigan Bay, the Bristol Channel and north of Holyhead suggested the angel shark was regularly staying in Welsh waters, ZSL's Joanna Barker told the BBC.
“What we really want to try and understand is what sort of numbers are we talking about and where are their important habitats, because there could be some really critical areas for angel sharks in Wales,” she said.
The project has also turned up a number of photographs from the 1970s and 1980s of local fishermen who had caught angel sharks.
Since then the species has become protected and it is now illegal to catch it while fishing in British waters.
The unusual shark is especially valuable for scientists because it represents a completely different evolutionary process compared to other species.
Their bodies are broad and flat to allow them to linger on the ocean floor, half-buried in sand and mud, waiting for prey to swim near them.
“If we lose the angel shark, we lose a really important lineage of evolutionary history that we can’t get from any other shark species,” Ms Barker said.
“It’s actually quite an ancient family of sharks … It has evolved particular traits no other family has done.”
Once so common it was used only as crab bait, in recent years the angel shark’s numbers have sharply dropped, leading to its classification as critically endangered in 2010.
But because it is now a protected species, researchers worry that fisherman and others who do come across it are reluctant to report sightings and accidental catches.
Ben Wray, a marine ecologist at Natural Resources Wales, said when the project was launched last year anyone could come forward without worrying about getting in trouble.
“We want to dispel that feeling and let people know that it’s fine to come forward and record these sightings,” he said.
“This data will be vital in building a clearer picture of the status and ecology of angel sharks in Wales as well as informing the Wales angel shark action plan, which we hope will help guide the project towards success.”
The angel shark project is now touring coastal communities across Wales to raise awareness of the species and encourage locals to share any information and sightings with the team.
In particular, the scientists still want to find out if the sharks living off Wales are moving between there and their normal hunting grounds around the Canary Islands, or even an unknown third hotspot.
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