Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (DY1503, 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 Shelikof Strait, Marmot Bay, and Chirikof shelf break areas of the Gulf of Alaska (GOA) during late winter/early spring of 2015 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The survey was conducted 15-31 March (Marmot Bay, 15-16 March; Shelikof Strait 17-23 March; Chirikof shelf break, 23-24 March), starting and ending in Kodiak, Alaska. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary instrument for the survey was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz).

Acoustic-trawl (AT) survey of Walleye Pollock in the Gulf of Alaska (DY1502, 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 Shumagin Islands, Sanak Trough, and Kenai peninsula bays in the Gulf of Alaska (GOA) during winter of 2015 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The survey was conducted 10 February to 2 March with the vessel departing and returning to Kodiak, Alaska (an intermediate port call in Kodiak, 14-18 February, was required due to a vessel mechanical issue). The Shumagin Islands survey was conducted 13 February and 20-24 February, the Sanak Trough survey was conducted 22-23 February, and the Shumagin Trough survey was conducted 23-24 February. The Shumagin Islands survey included Stepovak Bay, Unga Strait, and West Nagai Strait. The Kenai peninsula bays survey was conducted 27 February to 1 March and included Resurrection Bay, Day Harbor, Port Bainbridge, Ailik Bay, Harris Bay, Nuka Bay, Nuka Passage, and Port Dick. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary instrument for the survey was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz).

Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (DY1604, 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 Shelikof Strait and Marmot Bay areas of the Gulf of Alaska (GOA) during late winter/early spring of 2016 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The Shelikof Strait survey was conducted 14-21 March, and the Marmot Bay survey was conducted 22-24 March, 2016. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation.

Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1602, 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 winter of 2016 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The Shumagin Islands survey was conducted 12-15 February and included Shumagin Trough, Stepovak Bay, Renshaw, Unga Strait, Korovin Strait, and West Nagai Strait. The Sanak Trough survey was conducted 15-16 February followed by the Morzhovoi Bay survey on 16 February. The vessel transited to Pavlov Bay 16-17 February and completed the Pavlov survey on February 17. The vessel transited to its home port 18-20 February. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation.

Acoustic-Trawl Surveys of Walleye Pollock in the Gulf of Alaska (DY1701, EK60). The Midwater Assessment and Conservation Engineering (MACE) program of NOAA Fisheries, Alaska Fisheries Science Center (AFSC) conducted acoustic-trawl (AT) stock assessment surveys in the Gulf of Alaska (GOA) during the winter and early spring of 2017 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). These surveys were conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary instrument for the surveys was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz). The vessel departed Kodiak, Alaska on 7 February and conducted the Shumagin Islands survey (including Shumagin Trough from Renshaw Point to Simeonof Island, Stepovak Bay, Unga Strait, and West Nagai Strait) 8-11 February. The Sanak Trough survey was conducted on 11 February followed by the Morzhovoi Bay survey on 12 February. The vessel transited to Pavlov Bay and conducted the Pavlov survey 13-14 February. A calibration of the echosounder system was conducted on 14 February in Volcano Bay, Alaska. The vessel returned to its homeport of Kodiak, Alaska on 16 February, 2017.

Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1403, 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 Shelikof Strait, Marmot Bay, and Izhut Bay areas of the Gulf of Alaska (GOA) during late winter/early spring of 2014 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The survey was conducted 13-25 March (Shelikof Strait 15-22 March; Marmot and Izhut Bays 22-24 March), departing from Dutch Harbor, Alaska and ending in Kodiak, Alaska. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary instrument for the survey was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz).

Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1401, 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 Shumagin Islands and Sanak Trough areas of the Gulf of Alaska (GOA) during the winter of 2014 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The survey was conducted 21-28 February (Shumagin Islands 23-27 February; Sanak Trough 26 February), starting and ending in Kodiak, Alaska. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary instrument for the survey was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz).

Acoustic-Trawl Surveys of Walleye Pollock in the Gulf of Alaska (DY2017-03). The Midwater Assessment and Conservation Engineering (MACE) program of NOAA Fisheries, Alaska Fisheries Science Center (AFSC) conducted acoustic-trawl (AT) stock assessment surveys in the Gulf of Alaska (GOA) during the winter and early spring of 2017 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The surveys were conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary instrument for the survey was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz). The vessel departed Kodiak, Alaska on 14 March and surveyed Spruce Gully and inner Marmot Bay 14-15 March. The vessel returned to Kodiak for an unscheduled port call 15-17 March and departed Kodiak on 18 March. The Shelikof Strait survey was conducted 18-24 March followed by the Chirikof Shelfbreak survey 24-25 March. The outer Marmot Bay survey was conducted on 26 March. A sphere calibration of the echosounder system was conducted in Volcano Bay, Alaska on 14 February and at the end of the current cruise in Izhut Bay, Alaska on 27 March; no significant differences in gain parameters or transducer beam pattern characteristics were noted between the two calibrations. The vessel arrived at its homeport of Kodiak, Alaska on 27 March.

Acoustic-Trawl Surveys of Walleye Pollock in the Gulf of Alaska (DY1702, EK60). The Midwater Assessment and Conservation Engineering (MACE) program of NOAA Fisheries, Alaska Fisheries Science Center (AFSC) conducted acoustic-trawl (AT) stock assessment surveys in the Gulf of Alaska (GOA) during the winter and early spring of 2017 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). These surveys were conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary instrument for the surveys was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz). The vessel departed Kodiak, Alaska on 1 March and conducted the Kenai Bays survey (including Port Dick, Nuka Passage, Harris Bay, Aialik Bay, Resurrection Bay, Day Harbor, and Port Bainbridge) 2-5 March. The Prince William Sound, Hinchinbrook Trough and Middleton Island surveys were conducted 5-9 March. A calibration of the echosounder system was conducted during the previous cruise on 14 February in Volcano Bay, Alaska. The vessel arrived at its homeport of Kodiak, Alaska on 10 March, 2017.

Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1201, 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 winter of 2012 to estimate the distribution and abundance of walleye pollock (Theraga chalcogramma). The vessel departed Kodiak, Alaska on 13 February, conducted EK60 echosounder system calibration on 14 February, then proceeded to the start of the first survey (Sanak Trough, 15 February). The vessel then proceeded to the Shumagin Islands and conducted surveys at Shumagin Trough, Stepovak Bay, Renshaw Point, Unga Strait, and West Nagai Strait, 16-19 February. The vessel conducted multibeam echosounder surveys of select locations and deployed ARGO drifters 19-22 February and returned to Kodiak on 22 February. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation.