The pollution could be tipping the "king of fish" into an "extinction vortex" from which it may never recover, say environmentalists and anglers.
Figures released by the Scottish Executive, in response to a freedom of information request, reveal that there have been 93 escape incidents at fish farms between 2001 and October 2006.
The highest number of escapes took place last year, when the total topped one million. Damage caused by storms on 11 January, 2005, enabled 850,000 salmon to swim free from their cages in the Western Isles, the Highlands and Orkney.
Source: Sunday Herald