| Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY0901, ME70). 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 echosounder system
calibrations in Three Saints Bay, Kodiak Island, Alaska. 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. |