chum salmon vs Oncorhynchus keta

chum salmon and Oncorhynchus keta both are nouns.

Word	Noun	Adjective	Verb	Adverb
chum salmon	Yes	No	No	No
Oncorhynchus keta	Yes	No	No	No

As nouns, chum salmon and Oncorhynchus keta are synonyms defined as:

chum salmon and Oncorhynchus keta: a large Pacific salmon with small spots on its back; an important food fish

Other synonyms of chum salmon include chum.

chum salmon (noun)	Oncorhynchus keta (noun)
a large Pacific salmon with small spots on its back; an important food fish	a large Pacific salmon with small spots on its back; an important food fish