Data report: 1991 bottom trawl survey of the Aleutian Islands area

Abstract

The Resource Assessment and Conservation Engineering (RACE) Division of the Alaska Fisheries Science Center, Seattle, Washington, conducted a groundfish resources survey of the Aleutian Islands region from July to September 1991. Previous surveys in this region occurred in 1980, 1983, and 1986. The survey area covered the southern Bering Sea, from long. 165°W to 170°W and the Aleutian Islands waters, from long. 170°W to 170°30'E. Two chartered vessels, the Green Hope and Ocean Hope 1, completed 377 preselected stations covering the continental shelf and slope from 16 m to 521 m in depth. Both vessels were equipped with standard RACE Division Nor'eastern high-opening bottom trawls rigged with rubber bobbin roller gear.

The primary survey objectives were to define the distribution and relative abundance of the principal groundfish and commercially important invertebrate species inhabiting the Aleutian Islands region from near shore to approximately 500 m in depth and to collect data to define selected biological parameters for age, growth, length-weight relationships, feeding habits, and size, sex, and age composition. The survey also collected ancillary data and specimens requested by other research groups.

Survey results are presented, including estimates of biomass and catch per unit of effort, species distribution, length frequency distributions, and length-weight relationships for important commercial species.

A total of 111 fish species were identified from the survey catches. Walleye pollock, Pacific cod, Atka mackerel, Pacific ocean perch, and northern rockfish were the dominant species within the survey region. Sablefish, Pacific halibut, arrowtooth flounder, and giant grenadier were locally abundant in some areas. The only abundant invertebrate in the survey region was red (magistrate armhook) squid, which was the sixth most abundant species in the Southwest Aleutian Islands area.


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