Data report: 1993 Gulf of Alaska bottom trawl survey

Abstract

The fourth triennial groundfish assessment survey of the Gulf of Alaska was conducted during the summer of 1993 by the Alaska Fisheries Science Center's Resource Assessment and Conservation Engineering (RACE) Division and the Auke Bay Laboratory (ABL). The survey area covered the continental shelf and the upper continental slope to 500 m in the Gulf of Alaska from Islands of Four Mountains (170°W long.) to Dixon Entrance (133°25'W long.). The RACE portion of the survey was conducted aboard three chartered trawlers, the Argosy, Alsea, and Progress. The ABL portion was conducted aboard the National Oceanic and Atmospheric Administration's (NOAA) research vessel Miller Freeman. A total of 775 survey stations was successfully sampled using standard RACE Division 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 the principal groundfish and commercially important invertebrate species within the survey area and to collect data on biological parameters useful to groundfish researchers and managers including age, growth, length-weight relationships, feeding habits, and size, sex, and age composition. The survey also collected ancillary data requested by other research groups.

A total of 128 fish species were identified from the survey catches. Arrowtooth flounder (Atheresthes stomias), Pacific halibut (Hippoglossus stenolepis), walleye pollock (Theragra chalcogramma), Pacific cod (Gadus macrocephalus) and Pacific ocean perch (Sebastes alutus) were the most abundant species within the survey area. Rock sole (Pleuronectes bilineata), sablefish (Anoplopoma fimbria), yellowfin sole (Pleuronectes asper), and redstripe rockfish (Sebastes proriger) were locally abundant in some areas. Survey results are presented including estimates of catch per unit effort and biomass, species distribution, length frequency distribution,and length-weight relationships for commercially important species encountered during the survey.


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