A "sizeable" leatherback turtle has been spotted in Loch Long, according to Clyde harbour authorities.

The King's Harbourmaster Clyde says the animal was seen in the vicinity of Arrochar on Sunday, September 11 – and has asked mariners to report any further sightings.

In an announcement on Wednesday afternoon a spokesperson for KHM Clyde, the statutory authority for the Clyde Dockyard Port in the Gareloch and Loch Long, said: "Mariners are advised that we have been notified of a confirmed sighting of a leatherback turtle in the vicinity of Arrochar in Loch Long on September 11, 2022.

"Mariners are advised to navigate with caution in this area as this is a sizeable creature which could pose a hazard to smaller vessels.

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"As this is an endangered species, mariners are requested to report any sightings of the creature to either KHM Harbour Control or the Ministry of Defence Police Clyde Marine Unit."

According to the Marine Conservation Society UK, the leatherback, the largest marine turtle, is the species most frequently recorded in UK waters.

Leatherbacks have a flexible, leathery shell and are unique among reptiles in that they are able to metabolically raise their body temperature above that of their surrounding environment, allowing them to survive in colder waters.

Each summer, leatherbacks migrate to UK waters where they feed on jellyfish.

They can weigh up to 1500 pounds and are the largest sea turtle species found in the ocean. 

The largest specimen recorded in Scottish waters was estimated at 8ft in length and was observed inshore between Dunnet Head and Brough in the north-east in 1992.