Don’t rush out of the water or off the beach if you see a gigantic shark moving slowly near the coast with its giant mouth open.  It is most likely a basking shark which is huge but harmless.  This is the largest fish in British waters and it can be seen near the coastline in Orkney.  It is rare to catch a glimpse, but if you do, it's an awesome sight.  It can weigh around 17 tons and the largest recorded in the world was more than 12m long.  They are usually 6-8m long and are a typical shark shape with a large dorsal fin.  They are plankton and small invertebrate filter feeders.  They typically move slowly with mouth open, filtering huge volumes of water to get food. In the winter they dive to great depths to get plankton while in the summer they are mostly near the surface, where they appear to be basking.  Hotspots for basking shark sightings include Eynhallow and off the Old Man of Hoy.

One of Orkney’s greatest mysteries is the story of the Stronsay Beast.  In 1808 a dead monster was found decomposing on the rocks on Stronsay.  The giant creature was longer than an average basking shark and appeared to be serpent-like, which may have been due to the decomposition.  The creature had rotted away before zoologists of the day could do a thorough examination and descriptions matched no species they knew about.  Work to try and identify it is ongoing from a small sample that survived and from recorded eye witness accounts.  There is a strong possibility that the monster was a basking shark, according to Orcadian-born geneticist Dr Yvonne Simpson.