Assessment Of Groundfish Stocks Based On Bottom Trawl Survey Results PDF Download

Scientists of the Groundfish Assessment Program of Alaska Fisheries Science Center's Resource Assessment and Conservation Engineering (RACE) Division conducted the third biennial groundfish assessment survey of the Gulf of Alaska during the summer of 2003. These surveys extend the series of surveys, previously conducted every 3 years between 1984 and 1999, which constitute the time series used in stock assessments of Gulf of Alaska groundfish resources. The survey area covered the continental shelf and upper continental slope to 700 m in the Gulf of Alaska from Islands of Four Mountains (170° W long.) and continued eastward approximately 2,800 km across the Gulf of Alaska to Dixon Entrance (133° 25' W long.). The survey was conducted aboard three chartered commercial trawlers, the FV Gladiator, the FV Northwest Explorer and the FV Sea Storm. Trawl haul samples were collected successfully at 809 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 the principal groundfish within the survey area and to collect data to estimate 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. More than 176 fish and 362 invertebrate species were captured in survey tows. The species highest in total catch abundance (by weight) over the entire survey area were arrowtooth flounder (Atheresthes stomias), Pacific halibut (Hippoglossus stenolepis), Pacific ocean perch (Sebastes alutus), and walleye pollock (Theragra chalcogramma). Survey results are presented including estimates of catch per unit of effort, biomass, population size composition, and lengthweight relationships, as well as charts depicting the distribution of catch for commercially important species encountered during the survey. [doi:10.7289/V5/TM-AFSC-328 (http://dx.doi.org/10.7289/V5/TM-AFSC-328)]