Divers in Westcountry waters are being asked to help wildlife experts learn more about the behaviour of the world’s second largest fish – the basking shark.
Weighing in at seven tonnes and growing up to 11 metres long, the shark can grow to almost the same size and weight as a double-decker bus.
The huge fish can be seen around the local coastline during the summer months, slowly moving through the water as they feed on plankton and sometimes congregating in groups of 100 or more.
With their enormous mouths wide open, they can process 6,000 litres of sea water every hour, the equivalent to an Olympic-sized swimming pool.
Sightings of the basking shark have already been made by local divers, with three reported in the last week.
Now the Cornwall Wildlife Trust, together with other organisations, is asking for divers and other water users to report sightings to them to help the conservation effort for the species.
Ruth Williams, marine conservation officer for the trust, said: “What determines these sharks behaviour is not fully understood. We know that they, like other sharks, use an acute sense of smell and detection of electrical activity to track their tiny prey.
“But many aspects of their life remain a mystery and they continue to be a subject for ongoing survey and research.”
Despite being a protected species, basking sharks suffer threats from harassment by inquisitive water users, collisions with boats, and entanglement in fishing gear and marine litter.
It is hoped that a better understanding of their habits will help to protect them from such threats.
Divers and other water users have been asked to ensure they abide the Basking Shark Code of Conduct if they see the fish, taking care not to disturb or harass them.
Basking shark sightings can be reported by phoning Joana or Ruth on 01872 273939 extension 207 or online at www.cornwallwildlifetrust.org.uk/ nature/marine/record
Any incidences of sharks entangled in nets should be reported to a marine strandings hotline number on 0845 2012626.