EK60 Water Column Sonar Data Collected During DY1307

Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1307, 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 during the late spring/early summer of 2013 in the Gulf of Alaska to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The survey was conducted on the Gulf of Alaska shelf extending from the Islands of Four Mountains to Yakutat Bay, 8 June to 9 August 2013, in three legs (leg 1, 8-26 June; leg 2, 30 June to 18 July; leg 3, 22 July to 9 August) aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The vessel departed Dutch Harbor, Alaska on 9 June with intermediate port calls in Kodiak, Alaska. Smaller surveys were also conducted in several bays and around islands including Sanak Trough (15 June), Morzhovoi Bay (15 June), Pavlof Bay (16 June), the Shumagin Islands area (including Renshaw Point, Unga Strait, and West Nagai Strait; 19-23 June), Mitrofania Island (22-23 June), Nakchamik Island (24-25 June), Shelikof Strait (1-7 July), Alitak Bay (9-10 July), Barnabas Trough (11-14 July), Chiniak Trough (14-16 July), Marmot Bay (16-17 July), Prince William Sound (29 July to 1 August), Kayak Island Trough (3-4 August), and Yakutat Trough (5-7 August). The cruise ended when the vessel arrived in Kodiak, Alaska on 9 August 2013.