Anne the angel shark put in some hours for her critically endangered species by giving birth to 19 babies in a three week labour.

The first pup was born prematurely three weeks ago. Since then a team of divers and aquarists have been looking after the one-and-a-half metre long mother shark in a special isolation tank.

The flat sandy shark with bulging eyes lives at Deep Sea World, Scotland's national aquarium. Keepers got excited when Anne started to look plumper and employed specialist vet Romain Pizzi to perform a scan on the shark pups inside their mother.

A tiny camera on an endoscope meant that the aquarium got a sneak preview of the babies before their arrival: the first ever shark ultrascan.

Deep Sea World's Zoological Manager, Chris Smith, said: "All the pups, including the one which was born prematurely, are doing extremely well.

"We have already got a number of them to take food from a stick which is a very positive sign. It's been an amazing effort by Anne and we're absolutely delighted that such a vulnerable species has bred successfully in captivity for the first time.

"For us to have had one pup would have been a cause for real celebration, to have 19 of them is nothing short of extraordinary."

Angel Sharks are vulnerable to trawls, set nets and bottom long lines.

They grow extremely slowly and mature at a large size, meaning few sharks reach an age where they are able to breed. Anne's 'litter' has helped numbers of the slowly declining population.

Five years ago they were declared critically endangered on the International Union for Conservation of Nature's red list of threatened species.

Chris Smith said: "We'll be sharing the information we have gained throughout the pregnancy and birth with other aquariums throughout Europe in the hope that we can replicate this success at other sites and help to protect the species from the threat of extinction"