EK60 Water Column Sonar Data Collected During DY1407

Acoustic-Trawl Survey of Walleye Pollock on the Eastern Bering Sea Shelf (DY1407, EK60). National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment survey on the eastern Bering Sea shelf during late spring/summer of 2014 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The survey was conducted from Bristol Bay in the U.S. to Cape Navarin, RusThe Midwater Assessment and Conservation Engineering (MACE) program of NOAA sia, 12 June to 13 August aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The vessel departed Dutch Harbor, Alaska on 12 June and returned to Dutch Harbor on 13 August. The cruise was completed in three legs (leg 1, 12-30 June; leg 2, 4-22 July; leg 3, 26 July to 13 August), with all port calls in Dutch Harbor, Alaska. The primary instrument for the survey was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz).