Seasonal distributions of Atka mackerel (Pleurogrammus monopterygius) in commercially-fished areas of the Aleutian Islands and Gulf of Alaska

Abstract

Analyses of the haul locations, and sex and length composition of Atka mackerel (Pleurogrammus monopterygius) caught by the commercial fishery in four areas in the Aleutian Islands and Gulf of Alaska from 1984 to 1994 revealed seasonal and small-scale spatial distribution patterns of the species related to its reproductive behavior and life history. In winter, fishery hauls were generally conducted in deeper water than in summer, and the exploited population was well-mixed by sex in each of the four areas. In summer, when spawning and nest-guarding by males occurs, commercial hauls had higher percentages of females, had fewer mature males greater than 35 cm in length, and occurred in the relatively shallow inshore waters in "spawning" areas of Seguam Pass, Amchitka Island, and Umnak Island. At a "feeding" area on Petrel Bank, the only difference between winter and summer fishery catches was an underrepresentation of Atka mackerel of both sexes greater than 35 cm in length in summer, suggesting that they abandoned this area to spawn elsewhere. Knowledge of the seasonal and small-scale spatial distributions of Atka mackerel will be useful in designing better surveys to assess abundance and for long-term management of the fishery.


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