Although best known for its giant shipwrecks, a huge find of a different kind has been discovered in one of Scotland's most historic stretches of water.

An extremely rare fan mussel has been discovered at Scapa Flow and it's twice the size of any other British sea shell. The 30cm specimen was spotted by Seasearch volunteer divers, in a horse mussel bed by one of the wrecks.

Prior to this exciting find, only fourteen other giant fan mussels (Atrina pectinata) have been reported by divers to the Marine Conservation Society, who co-ordinate the Seasearch dive programme, over the past two decades from around the United Kingdom, including three from Scotland. 

Chris Wood, UK and Ireland Seasearch Co-ordinator, who was part of the team that found and photographed the living specimen in Scapa Flow said "The fan shell is another example of something, once abundant in UK coastal waters, which has declined rapidly since the advent of industrial trawl fishing. It is now so rare that it is one of very few marine species protected throughout the UK from being intentionally or recklessly killed, injured or taken. It is also one of the priority features in the different processes to identify new marine protected areas currently underway in Scotland, England and Wales."