striped mullet vs grey mullet

striped mullet and grey mullet both are nouns.

Word	Noun	Adjective	Verb	Adverb
striped mullet	Yes	No	No	No
grey mullet	Yes	No	No	No

As nouns, grey mullet is a hypernym of striped mullet; that is, grey mullet is a word with a broader meaning than striped mullet:

striped mullet: most important commercial mullet in eastern United States
grey mullet: freshwater or coastal food fishes a spindle-shaped body; found worldwide

Other hypernyms of striped mullet include gray mullet, mullet.

striped mullet (noun)	grey mullet (noun)
most important commercial mullet in eastern United States	freshwater or coastal food fishes a spindle-shaped body; found worldwide
	highly valued lean flesh of marine or freshwater mullet