Atka mackerel (Pleurogrammus monopterygius) is a schooling, semi-demersal species distributed from the east coast of the Kamchatka Peninsula, Russia, throughout the Komandorskiye and Aleutian Islands, north to the Pribilof Islands, and eastward through the Gulf of Alaska to Southeast Alaska. Their center of abundance has been in the Aleutian Islands region, particularly from Buldir Island to Sequam Pass.

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Atka mackerel begin to recruit to the fishery at age 2 and many survive to 14 years. Fifty percent of the female population is estimated to have reached maturity at 31 cm (about 3.6 years old).  Atka mackerel migrate from the shelf edge to shallow coastal waters (5-30 m) to spawn. Spawning occurs in July -September along the Aleutian Islands. Eggs are adhesive and deposited in rock crevices. These nest are guarded by the males until hatching, which occurs about 40-45 days later. Atka mackerel eat copepods and euphausiids and, in turn, are prey for other fish, seabirds, Steller sea lions, and other marine mammals.

The patterns of the Atka mackerel fishery generally reflect the behavior the the species:

• the fishery is highly localized and usually occurs in the same few locations each year
• the schooling semi-demersal nature of the species makes if particularly susceptible to trawl gear fished on the bottom
• trawling occurs almost exclusively at depths less than 200 m.

Atka mackerel are a very difficult fish to survey because:

• they do not have a swim bladder, making them poor targets for hydroacoustic surveys
• they prefer hard, rough and rock bottom which makes sampling with standard survey bottom trawl gear difficult
• their schooling behavior and patchy distribution make the species susceptible to large variances in catches, which greatly affect area-swept estimates of biomass

During 2015, pollock made up 67% of the total groundfish catch off Alaska.  The pollock catch for 2015 was 1,490,780 metric tons (t), up approximately 3% from 2014.

The 2015 catch of flatfish, which includes yellowfin sole, rock sole and arrowtooth flounder, was 245,860 t or 11% of the total 2015 Alaska groundfish catch, down about 24% from 2014.

Pacific cod accounted for 321,100 t or 14.4% of the total 2015 Alaska groundfish catch. The Pacific cod catch was down about 4% from 2014.

Other important species (% of total 2015 catch and % change from 2014) are:  Atka mackerel 54,500 t (2.4%, up 70%), sablefish 11,690 t (.05%, down 5%), and rockfish 668,660 t (3%, up 6%).

(Source: 2005 North Pacific Groundfish Stock Assessment and Fishery Evaluation Reports for 2006.)