king mackerel vs Scomberomorus cavalla

king mackerel and Scomberomorus cavalla both are nouns.

Word	Noun	Adjective	Verb	Adverb
king mackerel	Yes	No	No	No
Scomberomorus cavalla	Yes	No	No	No

As nouns, king mackerel and Scomberomorus cavalla are synonyms defined as:

king mackerel and Scomberomorus cavalla: large mackerel with long pointed snout; important food and game fish of the eastern Atlantic coast southward to Brazil

Other synonyms of king mackerel include cavalla, cero.

king mackerel (noun)	Scomberomorus cavalla (noun)
large mackerel with long pointed snout; important food and game fish of the eastern Atlantic coast southward to Brazil	large mackerel with long pointed snout; important food and game fish of the eastern Atlantic coast southward to Brazil