Inner Sound

The Inner Sound is a strait in the Highlands that separates the Inner Hebrides from the mainland. It lies between Skye, Raasay, South Rona and the Applecross peninsula. The Royal Navy uses part of the strait for submarine testing at BUTEC. The water here reaches depths found nowhere else in the UK. A trench over 300 metres deep runs for more than two kilometres along the bottom. The strait holds Britain’s deepest waters, with one trench reaching 324 metres. Another cleft descends to 252 metres, separated by shallower ground. The seabed in the deeper trench is flat mud with steep slopes of up to sixty degrees on one side. In 2020 scientists found over a hundred flapper skate eggs here, one of the rarest fish in the world. The government responded by creating a protected area in 2021 to stop trawling and dredging. Archaeologists walked every stretch of the Inner Sound’s coast between 1999 and 2004. Their work uncovered 129 new sites from the Mesolithic period. One excavation at Sand revealed a shell midden from around seven thousand years ago. The same team also surveyed sea lochs nearby. The strait’s islands include South Rona, Raasay and Scalpay, each with its own quiet shores.