Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY0901, EK60). The Midwater
Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries
Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted acoustic-trawl (AT)
stock assessment surveys in the western Gulf of Alaska (GOA) during the winter of
2009 to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma).
The vessel departed Kodiak, Alaska on 12 February and conducted acoustic echosounder
system calibrations in Three Saints Bay, Kodiak Island, Alaska on 12-13 February.
The vessel conducted the Shumagin Islands survey (including Shumagin Trough, Stepovak
Bay, Renshaw Point, Unga Strait, and West Nagai Strait) 15-18 February. The vessel
then surveyed Sanak Trough on 18-19 February, followed by a survey of the continental
shelf break from Sanak Island to Unalaska Island 19-20 February. The vessel conducted
equipment research operations utilizing a lowered target strength transducer system
21-22 February and arrived in Dutch Harbor, Alaska on 22 February. The primary acoustic
echosounder system for this survey was a Simrad EK60; a Simrad ME70 multibeam echosounder
system was also operated for the duration of the cruise. The survey was conducted
aboard NOAA Ship Oscar Dyson, a 64 meter fisheries research stern trawler equipped
with acoustic and oceanographic instrumentation. |