Information for The Swan of Salen at Mareel, Lerwick (Concert). On a small tidal island on the shore of Loch Sunart lie the ruins of the iron age fortress of Dun Ghallain. It was here that our story took place. The Swan of Salen is an adaptation of Tchaikovsky's iconic Swan Lake, arranged for three clarsachs, retold through the lens of the Gaelic tale of Eala Shailein.