Salmoniformes (Salmon & Trout)  

Both salmon and sea trout occur in all the larger freshwater systems and sea trout are also found in many of the minor ones. The original sea trout gave rise to sedentary brown trout populations similar to those of the mainland.

Fluctuations in the Hebridean salmon catch suggest that the stock is affected by the same factors as those affecting Scottish west coast stocks generally: the vast-majority return to fresh water as grilse, while sea trout stocks have been declining over the last 25 years.

Brown trout and eels are almost ubiquitous. Charr occur in Lewis and parts of North Uist but have not been reported from Harris or South Uist and are now only present as sedentary forms. (Campbell & Willamson, 1979)