EK60 Water Column Sonar Data Collected During DY0903

Acoustic-Trawl Survey of Walleye Pollock in the Southeastern Aleutian Basin near Bogoslof Island (DY0903, EK60). The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment survey in the Bogoslof Island area of the southeastern Aleutian Basin during late winter of 2009 to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma). The survey was conducted 7-13 March, departing from Dutch Harbor, Alaska on 7 March and arriving in Kodiak, Alaska 15 March. A calibration of the Simrad EK60 echosounder system (the primary survey instrument) was conducted on 7 March. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter fisheries research stern trawler equipped with acoustic and oceanographic instrumentation.