Study uncovers the secret lives of basking sharks
The first study to successfully track a basking shark using a robot camera has shed new light on the behaviour of the world’s second-largest fish.
An autonomous ‘SharkCam’ underwater vehicle was deployed off Coll and Tiree last summer to observe and gather footage of the behaviour of basking sharks.
The REMUS SharkCam technology is owned and operated by the Woods Hole Oceanographic Institution (WHOI) and the project is funded by WWF/Sky Ocean Rescue, NatureScot, WHOI and the University of Exeter.
Little is known about the underwater behaviour of the globally-endangered species, despite basking sharks being prevalent in the waters off the west coast of Scotland.
The SharkCam followed three basking sharks below the surface of the water, collecting video of their behaviour from a distance as they swam off the coast the Hebridean islands.
Published
The international team of researchers recently published their findings in the journal Animal Biotelemetry, and they reveal that the sharks spending an unexpected amount of time swimming near the seabed - a behaviour which has not often been reported for the species.
Notably the sharks were not seen to be feeding – which researchers believe adds weight to the theory that the species visits Scottish waters not to feed but to breed.
Innovative
Dr Suzanne Henderson, marine ecosystems manager with NatureScot (formerly known as Scottish Natural Heritage), 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. It suggests we may have to rethink not only how many basking sharks are in Scottish waters, but why they are here, as it’s likely not only the plankton they come for.
‘The insights the technology has provided about the habitats the sharks use are also invaluable, and will help inform how we protect and conserve the species in future.’
Fieldwork for the project took place in the proposed Sea of the Hebrides Marine Protected Area (MPA) – one of four possible MPAs currently under consideration by the Scottish Government.
The area is one of only a few worldwide where large numbers of basking sharks are found feeding in the surface waters each year.