Some beats on famous rivers like the Spey and the Nith recorded not a single salmon caught during the entire season.
Just two salmon were caught on the River Fyne in Argyll this year, where once more than 700 were caught each season.
The number of fish caught by anglers has been so low that some estates have stopped selling permits for once-popular beats because there is no fish to catch.
Tourism has been hit, sales of salmon tackle have slumped and ghillies have lost their jobs.
Experts believe rising temperatures blamed on global warming have badly hit the salmon’s feeding grounds with related changes in current patterns also affecting their migration.
Roger Brook, director of the Argyll Fisheries Trust, said: “Salmon are in decline everywhere but they’re declining more on the west coast of Scotland and they’re declining more the further down the west coast you go.
“It’s dreadful now in Argyll. It’s a crisis in Argyll. I don’t know whether it’s too late now to put it right.”
This year’s cold spring and the summer heatwave created the “perfect storm” for poor fishing conditions. But experts believe the steep decline in numbers since the 1960s is deep-rooted and warn the future is bleak. Survival rates for salmon at sea have fallen as low as 3 per cent with global warming and ocean fishing fleets among the likely causes.
Professor Ken Whelan, a leading salmon specialist investigating the downturn, said: “Absolutely there’s a crisis in salmon fishing. What we have now is a situation where you’re looking at very modest numbers of fish coming back and you really can’t afford to lose any from any kind of man-made effects.”
Andrew Flitcroft, editor of Trout & Salmon magazine, said: “This has been undoubtedly the worst season I’ve witnessed in my lifetime.”