What is "atka mackerel"

Yellowfish \Yel"low*fish`\, n. (Zo["o]l.) A rock trout ( Pleurogrammus monopterygius) found on the coast of Alaska; -- called also striped fish, and Atka mackerel.

The Atka mackerel (Pleurogrammus monopterygius) is a mackerel in the family Hexagrammidae. Atka mackerel are common to the northern Pacific ocean, and are one of only two members of the genus Pleurogrammus - the other being the Arabesque greenling (Pleurogrammus azonus). The Atka mackerel was named for Atka Island (Atx̂ax̂ in Aleut), the largest island of the Andreanof islands, a branch of the Aleutians.