EK60 Water Column Sonar Data Collected During DY0904

Acoustic-Trawl Surveys of Walleye Pollock in the Central Gulf of Alaska (DY0904, 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 central Gulf of Alaska (GOA) during the late winter/early spring of 2009 to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma). The vessel departed Kodiak, Alaska on 19 March and conducted a survey along the central Gulf of Alaska shelf east of Chirikof Island 20-22 March. The vessel then surveyed Shelikof Strait 23-28 March and performed an acoustic equipment calibration on 29 March. The Marmot Bay survey was conducted 29-30 March followed by fisheries research equipment testing on 31 March. The vessel ended the cruise in Kodiak, Alaska on 1 April. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation.