Last year, a single female was recorded returning to one tributary of a river usually celebrated for its fish. Now a plan is in place to change things – but it’s proving controversial

On an unusually hot May day in Aberdeenshire, Edwin Third stands on the bank of the River Muick, a tributary of the UK’s highest river, the Dee, talking us through the rising threats to one of Scotland’s most celebrated species, the Atlantic salmon. Against the hills of the Cairngorms national park, a herd of stags on the moorland bask in the sun.

It is a spectacular landscape, attracting hikers, mountain-bikers and salmon fishers, the latter contributing an estimated £15m to Aberdeenshire’s economy.