roe vs shad roe

roe and shad roe both are nouns.

Word	Noun	Adjective	Verb	Adverb
roe	Yes	No	No	No
shad roe	Yes	No	No	No

As nouns, shad roe is a hyponym of roe; that is, shad roe is a word with a more specific, narrower meaning than roe:

Other hyponyms of roe include coral, caviar, caviare.

roe (noun)	shad roe (noun)
eggs of female fish	roe of shad; may be parboiled or baked or sauteed gently
the eggs or egg-laden ovary of a fish
the egg mass or spawn of certain crustaceans such as the lobster
fish eggs or egg-filled ovary; having a grainy texture