AFSC Inter-Vessel Comparison of NOAA Ships Oscar Dyson and Miller Freeman in the Shelikof Strait Area (OD0704, EK60). The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted an inter-vessel acoustic-trawl (AT) comparison of NOAA Ships Oscar Dyson and Miller Freeman in the Shelikof Strait area of the Gulf of Alaska 11-25 March 2007. The inter-vessel comparison was conducted aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation, utilizing a Simrad EK60 split-beam echosounder system equipped with five frequencies (18, 38, 70, 120, and 200 kHz). The vessel departed Dutch Harbor, Alaska on 11 March and arrived in Kodiak, Alaska 25 March. The EK60 echosounder system was calibrated at the end of the previous cruise in Portage Bay (Makushin Bay), Unalaska Island, Alaska on 10 March and a final system calibration was conducted in Uyak Bay, Kodiak Island, Alaska on 23 March.

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.

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 Surveys of Walleye Pollock (DY0901, 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 western Gulf of Alaska (GOA) during the winter of 2009 to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma). The vessel departed Kodiak, Alaska on 12 February and conducted acoustic echosounder system calibrations in Three Saints Bay, Kodiak Island, Alaska on 12-13 February. The vessel conducted the Shumagin Islands survey (including Shumagin Trough, Stepovak Bay, Renshaw Point, Unga Strait, and West Nagai Strait) 15-18 February. The vessel then surveyed Sanak Trough on 18-19 February, followed by a survey of the continental shelf break from Sanak Island to Unalaska Island 19-20 February. The vessel conducted equipment research operations utilizing a lowered target strength transducer system 21-22 February and arrived in Dutch Harbor, Alaska on 22 February. The primary acoustic echosounder system for this survey was a Simrad EK60; a Simrad ME70 multibeam echosounder system was also operated for the duration of the cruise. 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 (Gadus chalcogrammus) in the Gulf of Alaska (SH2019-04). 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 Shelikof Strait, Chirikof shelf break,and Marmot Bay areas of the Gulf of Alaska (GOA) in the late winter/early spring of 2019 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). This survey was conducted aboard NOAA Ship Bell M. Shimada, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary acoustic 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 6 March and conducted an acoustic system calibration in Kalsin Bay, Kodiak Island 7 March. The Shelikof Strait was conducted 7-16 March, the Chirikof shelf break sure was conducted 16-18 March, and the Marmot Bay survey was conducted 19-20 March. A post-cruise acoustic system calibration was conducted 20-21 March in Kalsin Bay and the vessel arrived in Kodiak, Alaska on 21 March.

Oceanographic Survey of Cross Seamount and Control Sites (OES0703L1, EK60). The goals of the cruise were to collect acoustic backscatter and oceanographic data at Cross Seamount (18°43.285’ N, longitude 158° 15.710’ W), with an approximately 400 m deep plateau, and at control sites in the surrounding environment. Data collected consisted of CTD casts, trawl samples, and continuous monitoring of currents and biological acoustic backscatter. CTD cats were conducted at predetermined stations. CTDs were equipped with oxygen sensors and fluorometers, and water was sampled at discrete depths during each cast for chloropigment determinations. Trawl operations were conducted at predetermined stations using a Cobb trawl at depths of the shallow (nighttime) and deep (day and nighttime) sound scattering layers. Currents were continuously monitored using a RD Instruments Acoustic Doppler Current Profiler (ADCP) operating at 75 kHz frequency. Biological backscatter were recorded using the EK60 echosounder system (38, and 120 kHz) along predetermined transects.

Oceanographic Survey of Cross Seamount and Control Sites (OES0505, EK60). The goal of the cruise was to collect physical and biological oceanographic data at three distinct environment in the lee of the Island of Hawaii: a relatively near-shore pelagic environment off Keahole Point, Hawaii, at Finch Seamount (17° 38.070’N, longitude 157° 41.723’W) with a 1052 m deep peak, and at Cross Seamount (18°43.285’ N, longitude 158° 15.710’ W), with an approximately 400 m deep plateau. Data collected consisted of CTD casts, trawl samples, and continuous monitoring of currents and biological acoustic backscatter. CTD cats were conducted at predetermined stations. CTDs were equipped with oxygen sensors and fluorometers and water was sampled at discrete depths during each cast for chloropigments and nutrients measurements. Trawl operations were conducted at predetermined stations using a Cobb trawl at depths of the shallow (nighttime) and deep (day and nighttime) sound scattering layers. Currents were continuously monitored using a RD Instruments Acoustic Doppler Current Profiler (ADCP) operating at 75 kHz frequency. Biological backscatter were recorded using the EK60 echosounder system (38 and 120 kHz) along predetermined transects. During the survey, a High-frequency Acoustic Recording Package (HARP) was deployed for marine mammal observation.

Oceanographic Survey in the American Samoa Exclusive Economic Zone (EEZ) (OES0403, EK60). Oceanographic data were collected along predetermined transects in the American Samoa EEZ. CTD cats were conducted at predetermined stations. CTDs were equipped with oxygen sensors and fluorometers, and chlorophyll and nutrients were measured at discrete depths. Biological backscatter were monitored using the EK60 echosounder system (38, and 120 kHz) along the transects. Currents were continuously recorded using an RD Instruments Acoustic Doppler Current Profiler (ADCP).

Coral reef monitoring and mapping at US Line Islands (OES0404, EK60). The goal of the cruise was to conduct ecosystem surveys in tropical waters near the islands of Jarvis, Palmyra, and Kingman. Surveys were conducted using the Rapid Ecological Assessment (REA) method and by toad divers for fish, corals, invertebrates, and algae. Oceanographic assessment of the reef ecosystem was conducted by CTD casts for temperature and salinity and Acoustic Doppler Current Profiles for currents. Surface and subsurface temperature were also collected by towed divers and surface temperature, salinity, and fluorometer readings were continuously recorded by instruments on the Sette. Long-term monitoring was accomplished by deployment and retrieval of a variety of internally recording devices. Acoustic backscatter was monitored using an EK60 system at 38 and 120 kHz frequencies. Terrestrial wildlife visual surveys were conducted at the islands/atoll for sea and shorebirds.

Oceanographic Survey in the American Samoa Exclusive Economic Zone (EEZ) (OES0602, EK60). Oceanographic data were collected along five predetermined transects in the American Samoa EEZ and consisted of CTD casts, trawl samples, and continuous current and EK60 recordings. CTD cats were conducted at predetermined stations. CTDs were equipped with oxygen sensors and fluorometers. Trawl operations were conducted at predetermined stations along the transects using a Cobb trawl at depths of the shallow and deep sound scattering layers. Currents were continuously monitored using a RD Instruments Acoustic Doppler Current Profiler (ADCP). Biological backscatter were recorded using the EK60 echosounder system (38, and 120 kHz) along the transects.