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 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 (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 (DY1103, 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/summer of 2011 in the Gulf of Alaska to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma). The survey was conducted on the Gulf of Alaska shelf extending from the Islands of Four Mountains to the Chiniak Trough east of Kodiak Island, 14 June to 12 August 2011, in three legs (leg 1, 14-29 June; leg 2, 5-22 July; leg 3, 6-12 August) aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The vessel departed Kodiak, Alaska on 14 June with intermediate port calls in Kodiak, Alaska. An extended port call occurred between legs 2 and 3 (22 July to 6 August) due to vessel mechanical issues. Smaller surveys were also conducted in several bays and around islands including Morzhovoi Bay (22 June), Sanak Trough (23 June), Pavlof Bay (25 June), the Shumagin Islands area (7-8 July), Mitrofania Island (9-10 July), Nakchamik Island (11-12 July), Shelikof Strait (16-21 July), Chiniak Trough (7-8 August), Barnabas Trough (9-10 and 11-12 August), and Alitak Bay (10-11 August). The cruise ended when the vessel arrived in Kodiak, Alaska on 12 August 2011.

Gulf of Alaska Acoustic-Trawl Surveys of Walleye Pollock (DY1203, 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 late winter/early spring of 2012 to estimate the distribution and abundance of walleye pollock (Theraga chalcogramma). The survey was conducted along the Gulf of Alaska shelf break east of Chrikof Island (17-19 March) and throughout the Shelikof sea valley (20-26 March). The vessel departed Kodiak, Alaska on 5 March for the start of cruise DY1202 and was at sea for the start of the Chirikof shelf break survey. The vessel conducted a personnel transfer in Kodiak on 19 March then proceeded to the Shelikof Strait survey area. A post-cruise EK60 echosounder system calibration was conducted on 26 March in Malina Bay, Afognak Island, Alaska and the vessel returned to Kodiak at the completion of the cruise on 27 March. 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 (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.

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 (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).

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.

Assessment of Rockfish Species in Untrawlable Habitat in the Gulf of Alaska (DY0912, EK60). The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted an assessment of northern rockfish (Sebastes polyspinis) and dusky rockfish (Sebastes variabilis) in untrawlable habitat areas of the Gulf of Alaska using advanced acoustics, optical, and trawl technologies, 3-13 October 2009. The primary survey site was a shallow bank along the GOA shelf break known as Snakehead. The survey was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary acoustic instruments for this survey were the Simrad EK60 split beam echosounder and the Simrad ME70 multibeam echosounder. The vessel departed Dutch Harbor, Alaska on 3 October and ended the cruise on 13 October in Kodiak, Alaska. The survey was conducted 4-12 October with a weather delay on 10 October.