red salmon vs Oncorhynchus

red salmon and Oncorhynchus both are nouns.

Word	Noun	Adjective	Verb	Adverb
red salmon	Yes	No	No	No
Oncorhynchus	Yes	No	No	No

red salmon (noun)	Oncorhynchus (noun)
small salmon with red flesh; found in rivers and tributaries of the northern Pacific and valued as food; adults die after spawning	Pacific salmon including sockeye salmon, chinook salmon, chum salmon, coho salmon
fatty red flesh of salmon of Pacific coast and rivers