menhaden vs Brevoortia tyrannis

menhaden and Brevoortia tyrannis both are nouns.

Word	Noun	Adjective	Verb	Adverb
menhaden	Yes	No	No	No
Brevoortia tyrannis	Yes	No	No	No

As nouns, menhaden and Brevoortia tyrannis are synonyms defined as:

menhaden and Brevoortia tyrannis: shad-like North American marine fishes used for fish meal and oil and fertilizer

menhaden (noun)	Brevoortia tyrannis (noun)
shad-like North American marine fishes used for fish meal and oil and fertilizer	shad-like North American marine fishes used for fish meal and oil and fertilizer