Data report: 2002 Aleutian Islands bottom trawl survey

Abstract

Eighth in a series dating from 1980, the second biennial groundfish assessment survey of the Aleutian Islands region was conducted during the summer of 2002 by the Alaska Fisheries Science Center’s (AFSC) Resource Assessment and Conservation Engineering (RACE) Division.  The survey area covered the continental shelf and upper continental slope to 500 m in the Aleutian Archipelago from Islands of Four Mountains (170° W long.) to Stalemate Bank (170° E long.), including Petrel Bank and Petrel Spur (180° long.), and the northern side of the Aleutian Islands between Unimak Pass (165° W long.) and Islands of Four Mountains.  The survey was conducted aboard three chartered trawlers, the FV Morning Star, FV Sea Storm, and FV Vesteraalen.  Samples were collected successfully at 417 survey stations using standard RACE Division Poly Nor’Eastern high-opening bottom trawl nets with rubber bobbin roller gear.

The primary survey objectives were to define the distribution and estimate the relative abundance of principal groundfish and commercially or ecologically important invertebrate species that inhabit the Aleutian marine habitat and to collect data to define biological parameters useful to fisheries researchers and managers such as growth rates; length-weight relationships; feeding habits; and size, sex, and age compositions. 

Over 120 species of fish and over 315 species or species groups of invertebrates were captured in survey tows.  Atka mackerel (Pleurogrammus monopterygius), Pacific ocean perch (Sebastes alutus), northern rockfish (S. polyspinus), walleye pollock (Theragra chalcogramma), Pacific cod (Gadus macrocephalus), arrowtooth flounder (Atheresthes stomias), and giant grenadier (Albatrossia pectoralis) were the most abundant species captured within the survey area.  Atka mackerel and Pacific ocean perch were most abundant in the Aleutian region west of Islands of Four Mountains.  Walleye pollock and Atka mackerel were the most abundant species in the southern Bering Sea region, east of the Islands of Four Mountains.  Survey results are presented as estimates of catch per unit of effort and biomass, species distribution and relative abundance, length frequency distribution, and length-weight relationships for commercially important species and for others of biological interest.


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