lake trout vs salmon trout

lake trout and salmon trout both are nouns.

Word	Noun	Adjective	Verb	Adverb
lake trout	Yes	No	No	No
salmon trout	Yes	No	No	No

As nouns, lake trout and salmon trout are synonyms defined as:

lake trout and salmon trout: large fork-tailed trout of lakes of Canada and the northern United States

Other synonyms of lake trout include Salvelinus namaycush.

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