The first resident pod of bottlenose dolphins has been discovered off the south-west coast of England.
Experts used thousands of sightings and photos to identify a group of 28 individuals living year-round off the coasts of Cornwall, Devon and Dorset.
They were identified using their dorsal fins, which are as unique to dolphins as fingerprints are to humans.
Plymouth University researchers studied 3,843 records to identify 98 dolphins and among them the resident population.
The sightings, recorded between 2007 and 2016, established the group was present in shallow coastal waters, mainly off Cornwall and particularly near St Ives Bay and Mount's Bay.
Ruth Williams, marine conservation manager at the Cornwall Wildlife Trust, said: "Further work is needed but this is a huge step forward and I am proud of what our partnership between Cornwall Wildlife Trust, scientists and boat operators has achieved.
"We need to make sure the few we currently have in the south west are given the protection not just to survive, but to thrive."
Rebecca Dudley, of the University of Plymouth, gathered data from a large number of collaborators who had studied the dolphins' social structure and distribution.
She said her findings will raise questions about conservation of the environment the pod inhabits.
"This shows that if anything happens to their habitat in this area, it is really going to affect the population, because they do spend all their time around the south west region."
The UK's two other resident bottlenose dolphin populations - in Cardigan, Wales and Moray Firth, Scotland - both have protection.