Pholis gunnellus vs gunnel

Pholis gunnellus and gunnel both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pholis gunnellus	Yes	No	No	No
gunnel	Yes	No	No	No

As nouns, gunnel is a hypernym of Pholis gunnellus; that is, gunnel is a word with a broader meaning than Pholis gunnellus:

Pholis gunnellus: slippery scaleless food fish of the northern Atlantic coastal waters
gunnel: small eellike fishes common in shallow waters of the northern Atlantic

Other hypernyms of Pholis gunnellus include bracketed blenny.

Pholis gunnellus (noun)	gunnel (noun)
slippery scaleless food fish of the northern Atlantic coastal waters	small eellike fishes common in shallow waters of the northern Atlantic
	wale at the top of the side of boat; topmost planking of a wooden vessel