Are Silkies only a legend?

The Times 1809

In 1809 The Times had printed a report by a Scottish schoolmaster named William Munro describing his encounter, on the beach near Thurso, with:
“…. a figure resembling an un-clothed human female, sitting upon a rock extending into the sea, and apparently in the action of combing its hair, which flowed around its shoulders, and was of a light brown colour …. the forehead round, the face plump, the cheeks ruddy, the eyes blue, the mouth and lips of a natural form…. It remained on the rock three or four minutes after I observed it, and was exercised during that period in combing its hair, which was long and thick, and of which it appeared proud, and then dropped into the sea.”
Other local people also admitted to having seen similar creatures, their descriptions compatible with those of the schoolmaster.