A robot camera has been used in UK seas for the first time to monitor the behaviour of basking sharks.
SharkCam was deployed off the west coast of Scotland where the sharks gather to breed after migrating from waters off west Africa.
Basking sharks, an endangered species, are the world’s second largest fish after whale sharks, sometimes growing to more than 10m (33ft) long.
SharkCam followed three sharks off the coasts of Coll and Tiree.
The robot monitored the animals from a distance and recorded behaviour that suggested they arrive in Scottish waters to breed rather than feed.
Basking sharks can be seen swimming close to the surface of the sea with their large mouths open to catch plankton in the Inner and Outer Hebrides, as well as off Skye and the west Highland coast.
But studying the footage gathered last summer by SharkCam, scientists noted the sharks spent long periods just above the seabed and were not feeding.
NatureScot, formerly Scottish Natural Heritage, worked on the project with Woods Hole Oceanographic Institution, WWF/Sky Ocean Rescue and the University of Exeter.
Dr Suzanne Henderson, of NatureScot, said: “While we weren’t lucky enough to capture courtship or mating behaviour on camera this time, this innovative study has shed more light on the lives of these spectacular giant fish.
“The fact that the sharks spent much more time swimming just above the seabed than we previously thought, and with their mouths closed, is really interesting, particularly as the species is often seen as a pelagic or near-surface filter feeding shark.”