| Shumagin Islands Acoustic-Trawl Survey of Walleye Pollock (DY1302, ME70). 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. |