Driven by an instinctive urge to reach their spawning redds in the fast-flowing streams of the Scottish Highlands, salmon battle through rapids and waterfalls on their long journey from the sea.
Freshwater biologists, Niall Campbell and Mark Young visit the Tanar burn, a tributary of the Dee, and discover the salmon's destination.
Presented by Chris Lowell
(Revised version of a programme first broadcast on BBC Radio Scotland)
BBC Bristol