Scotland’s iconic wild salmon could be a few decades away from extinction.
The warning has been issued as scientists and charities pool their expertise for the most comprehensive measure so far to gauge the health of the species.
They believe current Atlantic salmon numbers are barely a third of those in the 1980s.
Scottish rivers are home to 90% of UK salmon and only 5% of young salmon that head to sea for food return as adult fish.
At that rate, it is estimated that wild Atlantic salmon could disappear by the middle of the century.
The Missing Salmon Alliance has been formed for a three-year mission to establish the threats and how to combat them.
It comprises the Atlantic Salmon Trust, Fisheries Management Scotland, the Angling Trust, the Game & Wildlife Conservation Trust, and the Rivers Trust.
Their largely privately-financed project also has backing from the Scottish Government.
Mark Bilsby of the Atlantic Salmon Trust said: “If we do nothing and carry on with this same rate of decline that we’ve got at the moment.. if you extrapolate that line out with the decline.. in 20, 30 years you’ve not just got salmon in crisis, you’ve got a species that may be lost.
“Can you imagine Scotland without that iconic species of salmon in it.”
Smolts – young salmon – are being acoustically tracked by an army of volunteers in seven rivers – the Shin, Oykel, Conon, Ness, Findhorn, Spey and the Deveron.
Chris Conroy of the Ness District Salmon Fishery Board said: “The fishing industry here – rod and line fishing – supports a huge number of jobs locally, not just the ghillies on the river but the accommodation, the tackle shops, restaurants, etc.
“So, if the salmon goes into decline it has a knock-on effect on the local economy.”
Interim results from the most extensive research of its kind are expected in November.