Summary

Description

The Midwater Assessment and Conservation Engineering (MACE) program of NOAA's National Marine Fisheries Service, Alaska Fisheries Science Center (AFSC), conducted an acoustic-trawl (AT) stock assessment survey in the Gulf of Alaska (GOA) during late winter of 2013 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The survey areas included the Shumagin Islands area (consisting of Shumagin Trough, Stepovak Bay, Renshaw Point, Unga Strait, and West Nagai Strait), Sanak Trough, and Morzhovoi Bay (February 26 to March 3, 2013). The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation in addition to biological sampling capabilities. The primary instrumentation for the survey was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz) and a Simrad ME70 multibeam echosounder, with the ME70 trigger synchronized to the EK60 system.