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.

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).

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).

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.

Echo Integration-Trawl Surveys of Walleye Pollock in Shelikof Strait and Along the Gulf of Alaska Shelf Break Between Chirikof and Middleton Islands 13-31 March, 2008 (OD2008-03). 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 area of the Gulf of Alaska (GOA) and along the GOA shelf break between Chirikof and Middleton Islands in the late winter/early spring of 2008 to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma). The survey was conducted 13-31 March, departing from Kodiak, Alaska on 13 March and arriving in Kodiak, Alaska 31 March. The Shelikof Strait, Chirikof shelf break and part of the Gulf of Alaska shelf break surveys were conducted 13-21 March, followed by an acoustic system calibration and weather delay 22-23 March. Gear selectivity and trawl net codend comparison experimental gear trials were conducted 24-26 March. The vessel transited to the Gulf of Alaska at Middleton Island on 27 March, and the survey of the Gulf of Alaska shelf break area was conducted 28-31 March. The vessel arrived in Kodiak, Alaska on 31 March. A calibration of the Simrad EK60 echosounder system (the primary survey instrument) was conducted in Captains Bay, Unalaska Island, Alaska on 15 March. A second calibration was conducted on 22 March in Kizhuyak Bay, Kodiak Island Alaska on 22 March. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter fisheries research stern trawler equipped with acoustic and oceanographic instrumentation.

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.

Acoustic-Trawl Surveys of Walleye Pollock in the Central Gulf of Alaska (DY0904, 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 central Gulf of Alaska (GOA) during the late winter/early spring of 2009 to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma). The vessel departed Kodiak, Alaska on 19 March and conducted a survey along the central Gulf of Alaska shelf east of Chirikof Island 20-22 March. The vessel then surveyed Shelikof Strait 23-28 March and performed an acoustic equipment calibration on 29 March. The Marmot Bay survey was conducted 29-30 March followed by fisheries research equipment testing on 31 March. The vessel ended the cruise in Kodiak, Alaska on 1 April. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation.

Echo Integration-Trawl Surveys of Walleye Pollock in the Shumagin Islands and Sanak Trough areas of the Gulf of Alaska, 6-15 February, 2008 (DY2008-01). 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 Shumagin Islands and Sanak Trough areas of the Gulf of Alaska (GOA) during the winter of 2008 to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma). This cruise was also used as an opportunity to compare results from acoustic-trawl surveys conducted simultaneously between NOAA Ships Oscar Dyson and Miller Freeman. This survey was conducted onboard NOAA Ship Oscar Dyson, departing from Kodiak, Alaska on 6 February and arriving in Dutch Harbor, Alaska on 15 February. A calibration of the echosounder system was conducted in Three Saints Bay, Kodiak Island, Alaska on 6 February. Both vessels (Freeman accompanying the Dyson) conducted the Shumagin Islands survey (including Shumagin Trough, Stepovak Bay, Renshaw Point, and Unga Strait) 7-12 February. The vessels conducted the survey of Sanak Trough 12-13 February. The experimental intervessel comparison work required that the vessels travel side-by-side along the survey transects at a separation distance of 0.5 nm, and at other times following each other at a distance of 1.0 nm along shorter transects. The intervessel comparison was designed to minimally impact efforts to complete the survey with the Miller Freeman as the primary survey vessel. A calibration of the Dyson echosounder system was conducted at the end of the survey in Captains Bay, Dutch Harbor, Alaska on 15 February. The Dyson arrived in Dutch Harbor, Alaska on 15 February, ending the cruise. The Dyson is a 64 meter fisheries research stern trawler equipped with acoustic and oceanographic instrumentation. The primary acoustic echosounder system installed on the Dyson is a Simrad EK60 scientific split beam echosounder utilizing five frequencies (18, 38, 70, 120, and 200 kHz).

Gulf of Alaska Acoustic-Trawl Survey of Walleye Pollock (DY1506, 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 Gulf of Alaska (GOA) during late spring/summer of 2015 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The survey area included the GOA shelf from the Islands of Four Mountains to Chiniak Trough including many associated bays and troughs. The survey was conducted from June 11 to August 16, 2015 in three legs, starting and ending in Kodiak, Alaska, with intermediate port calls 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 instrumentation 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.