EK60 Water Column Sonar Data Collected During DY1002

Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1002, 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 Gulf of Alaska (GOA) during the late winter/early spring of 2010 to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma). The vessel departed Kodiak, Alaska on 18 March and conducted a survey along the central Gulf of Alaska shelf east of Chirikof Island 18-19 March. The vessel conducted fisheries research operations on Snakehead shelf 19-22 March. The vessel then surveyed Shelikof Strait 22-28 March and returned to Kodiak, Alaska on 30 March following a post-cruise EK60 echosounder system calibration 29-30 March. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation.