John Connell goes fishing in northern Spain, home to one of the oldest populations of Atlantic salmon in the world.

But he discovers a world on an ecological edge - with water at dangerously low levels, distraught fishermen and virtually no fish.

'What is a fish without a river?' he asks. 'Indeed what is a river without a fish?'

Producer: Adele Armstrong
Sound: Neil Churchill
Production Coordinator: Iona Hammond
Editor: Richard Fenton-Smith