pollack vs Pollachius

pollack and Pollachius both are nouns.

Word	Noun	Adjective	Verb	Adverb
pollack	Yes	No	No	No
Pollachius	Yes	No	No	No

pollack (noun)	Pollachius (noun)
important food and game fish of northern seas (especially the northern Atlantic); related to cod	pollack
lean white flesh of North Atlantic fish; similar to codfish