salmon trout vs Salmo trutta

salmon trout and Salmo trutta both are nouns.

Word	Noun	Adjective	Verb	Adverb
salmon trout	Yes	No	No	No
Salmo trutta	Yes	No	No	No

As nouns, salmon trout and Salmo trutta are synonyms defined as:

salmon trout and Salmo trutta: speckled trout of European rivers; introduced in North America

Other synonyms of salmon trout include brown trout.

salmon trout (noun)	Salmo trutta (noun)
large fork-tailed trout of lakes of Canada and the northern United States	speckled trout of European rivers; introduced in North America
speckled trout of European rivers; introduced in North America
flesh of marine trout that migrate from salt to fresh water