Arctic char vs Salvelinus alpinus

Arctic char and Salvelinus alpinus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Arctic char	Yes	No	No	No
Salvelinus alpinus	Yes	No	No	No

As nouns, Arctic char and Salvelinus alpinus are synonyms defined as:

Arctic char and Salvelinus alpinus: small trout of northern waters; landlocked populations in Quebec and northern New England

Arctic char (noun)	Salvelinus alpinus (noun)
small trout of northern waters; landlocked populations in Quebec and northern New England	small trout of northern waters; landlocked populations in Quebec and northern New England