The Atka Mackerel (Pleurogrammus monopterygius) is a mackerel in the family Hexagrammidae. Atka mackerel are common in the northern Pacific ocean, and are 1 of only 2 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.
Atka mackerel migrate from shelves to coastal waters to spawn which occurs (in the Aleutians) from July to September. Their eggs adhere to crevices in the rocks, and incubate for 40–45 days. Males guard the clutches of eggs until they hatch. Atka mackerel feed on copepods and euphausiids. They are, in turn, preyed upon by several species, such as the coho salmon and the Steller sea lion.