A deep-sea shark spawning ground has been discovered in Scottish waters for the first time, according to marine biologists.
Egg cases of the blackmouth catshark have been found on the Mingulay coral reef complex in the Outer Hebrides.
Scientists from Edinburgh's Heriot-Watt University made the discovery while surveying the cold-water corals using a remotely operated vehicle. They said the shark nursery reinforces the need for the area to be granted marine protected status.
"It's very exciting to find these spawning sites, as there's still relatively little information about deep-sea sharks habitat across their life cycles," the university's Dr Lea-Anne Henry said.
"Our research at Mingulay and in even deeper Scottish waters is now revealing many close links between cold-water corals and the early life stages of sharks, skates and rays.
"The sharks are choosing these sites because they're safe. The corals have lots of hard branches which deter predators, and laying them away from the current in lower parts of the seabed reduces the risk of eggs drifting away. The height of the coral means the eggs receive plenty of air and that they're not suffocated by sediments and debris."
Protecting the spawning sites of the species, also known as Galeus melastomus, could also bring economic benefits, researchers say.
"Over 60% of sport anglers target catsharks when they fish this area, which brings in over £140 million to the Scottish economy each year," Dr Henry said.
"Sports anglers catch the sharks and release them back in the water, which helps us document and ultimately conserve the populations. Sharks aren't just part of this underwater ecosystem, they're a huge part of the local and national economy. We also spotted another species prized by anglers, the lesser-spotted catshark Scyliorhinus canicula, using the reef and there is also a nursery site for the critically endangered spurdog Squalis acanthias very close by."
The Mingulay complex, Scotland's only inshore coral reef, is awaiting designation as a marine protected area from the European Union.