EK60 Water Column Sonar Data Collected During DY0912

Assessment of Rockfish Species in Untrawlable Habitat in the Gulf of Alaska (DY0912, EK60). The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted an assessment of northern rockfish (Sebastes polyspinis) and dusky rockfish (Sebastes variabilis) in untrawlable habitat areas of the Gulf of Alaska using advanced acoustics, optical, and trawl technologies, 3-13 October 2009. The primary survey site was a shallow bank along the GOA shelf break known as Snakehead. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary acoustic instruments for this survey were the Simrad EK60 split beam echosounder and the Simrad ME70 multibeam echosounder. The vessel departed Dutch Harbor, Alaska on 3 October and ended the cruise on 13 October in Kodiak, Alaska. The survey was conducted 4-12 October with a weather delay on 10 October.