One of the world's "rarest" sharks, the angel shark, has been discovered by fishermen off the coast of Wales — a promising sign of life for the critically endangered creature.

The "flat bodied" sharks, which typically swim along the ocean floor, were recently reported off Cardigan Bay, the Bristol Channel and near Holyhead. Since the population of the angel shark continues to drastically decline, researchers decided to investigate.

Last year, the Zoological Society of London (ZSL) and Natural Resources Wales (NRW) started the "Angel Shark Project: Wales," encouraging people to contact them if they spot the sea creature. On Thursday, the groups asked residents to share photos and memories of the endangered species during their first "Angelshark History Roadshow."

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"Angel sharks are important to the marine environment as they are a top predator and are listed as the fifth most Evolutionarily Distinct and Globally Endangered shark in the world, representing a distinct branch of the tree of life," the ZSL explains on its website, noting the Welsh coast may be an important home for the species.

"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."

— Joanna Barker

Angel sharks used to be fairly common across the Atlantic and Mediterranean seas but a disrupted habitat, pollution and overfishing have been contributing to its demise, ZSL says. Scientists hope recent sightings will help provide clues to the species' behavior and preferred habitat and, in turn, help save the mysterious sharks from extinction.

"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," Joanna Barker, a marine biologist who works for the ZSL, told BBC News.

Barker has been studying the sharks for a while, particularly around the Canary Islands, but she's now starting to deep dive into their history in Welsh waters. With recent sightings, she is curious which locations the sharks are currently calling home and whether there are distinct populations.

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"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," Barker explained.

In order to further study the rare sharks, Barker said researchers will take swabs of their skin during dives scheduled for later this year.

Until then, marine experts hope to gain even more information about the angel sharks from locals — using their photos and stories to help track the movements of the species off the coast of Wales.