white seabass vs fish species

white seabass and fish species both are nouns.

Word	Noun	Adjective	Verb	Adverb
white seabass	Yes	No	No	No
fish species	Yes	No	No	No

As nouns, fish species is a hypernym of white seabass; that is, fish species is a word with a broader meaning than white seabass:

white seabass: a species of large perch noted for its sporting and eating qualities; lives in marine, estuary, and freshwater habitats
fish species: a species of fish

white seabass (noun)	fish species (noun)
a species of large perch noted for its sporting and eating qualities; lives in marine, estuary, and freshwater habitats	a species of fish