gov.noaa.nodc:0039614 eng utf8 dataset NOAA National Centers for Environmental Information ncei.info@noaa.gov https://www.ncei.noaa.gov/contact HTTPS NOAA Contact Information Information for contacts at NCEI. information custodian 2025-12-14T21:05:20Z ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) Aerial Surveys of Arctic Marine Mammals (ASAMM) collected by Marine Mammal Laboratory, Bureau of Ocean Energy Management, and other agencies in the Bering, Chukchi, Beaufort Seas, and Amundsen Gulf from 1979 to 2019 and North Slope Borough, Alaska from 2020 to 2021 (NCEI Accession 0039614) 2008-03-12 publication 2022-05-31 revision 2008-03-12 creation International DOI Foundation (IDF) 10.7289/v51v5bzm NOAA National Centers for Environmental Information gov.noaa.nodc:0039614 NCEI Archive Management System 0039614 NOAA National Centers for Environmental Information ncei.info@noaa.gov https://www.ncei.noaa.gov/contact HTTPS NCEI Contact Information Information for contacts at NCEI. information publisher Amy L. Willoughby NOAA Alaska Fisheries Science Center, Marine Mammal Laboratory (NMFS/AFSC/MML) amy.willoughby@noaa.gov https://www.fisheries.noaa.gov/about/marine-mammal-laboratory HTTPS NOAA Alaska Fisheries Science Center, Marine Mammal Laboratory (NMFS/AFSC/MML) website Institution web page information resourceProvider NOAA Alaska Fisheries Science Center (NMFS/AFSC) http://www.afsc.noaa.gov HTTP NOAA Alaska Fisheries Science Center (NMFS/AFSC) website Institution web page information resourceProvider BOEM, Alaska Outer Continental Shelf (OCS) Region http://www.boem.gov/ HTTP Bureau of Ocean Energy Management (BOEM) website Institution web page information author NOAA, National Marine Fisheries Service, Alaska Fisheries Science Center http://www.afsc.noaa.gov HTTP NOAA Alaska Fisheries Science Center (NMFS/AFSC) website Institution web page information author North Slope Borough author Megan Ferguson NOAA Alaska Fisheries Science Center (NMFS/AFSC) http://www.afsc.noaa.gov HTTP NOAA Alaska Fisheries Science Center (NMFS/AFSC) website Institution web page information pointOfContact Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) http://www.boemre.gov/ HTTP Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) website Institution web page information contributor NOAA Alaska Fisheries Science Center, Marine Mammal Laboratory (NMFS/AFSC/MML) https://www.fisheries.noaa.gov/about/marine-mammal-laboratory HTTPS NOAA Alaska Fisheries Science Center, Marine Mammal Laboratory (NMFS/AFSC/MML) website Institution web page information contributor Bureau of Ocean Energy Management (BOEM) http://www.boem.gov/ HTTP Bureau of Ocean Energy Management (BOEM) website Institution web page information contributor US Minerals Management Service (MMS) contributor tableDigital This dataset contains aerial survey data from the surveys described below. The Bureau of Ocean Energy Management (BOEM), formerly the Minerals Management Service (MMS), and its precursor, the Bureau of Land Management, funded aerial surveys in the Beaufort, Chukchi, and Bering seas from 1979 to 2019. In 2008, through an Interagency Agreement between MMS and the Alaska Fisheries Science Center (AFSC, National Marine Fisheries Service, National Oceanic and Atmospheric Administration [NOAA]), the Marine Mammal Laboratory (MML, a division of AFSC), formerly the National Marine Mammal Laboratory, assumed co-management responsibilities for these surveys. Throughout the history of the surveys, they were referred to as the Bowhead Whale Aerial Survey Project (BWASP) and the Chukchi Offshore Monitoring in Drilling Area (COMIDA) marine mammal aerial surveys, both of which are described in more detail below. The surveys were conducted under the auspices of a single study, Aerial Surveys of Arctic Marine Mammals (ASAMM). In 2020 and 2021, aerial line-transect surveys for bowhead whales and other marine mammals were funded and co-managed by the North Slope Borough (NSB) through contract 2021-069 with the Cooperative Institute for Climate, Ocean, and Ecosystem Studies, a part of the University of Washington, with collaboration from AFSC, NOAA Fisheries. Consistent survey protocol has been in effect on surveys conducted since 1982. WESTERN BEAUFORT SEA Aerial surveys in the western Beaufort Sea (south of 72 degrees N, 140-157 degrees W) have been conducted each year since 1979. MMS personnel and contractors conducted the surveys from 1979 to 2007. From 2008 to 2019, the surveys were conducted by MML. In 2020 and 2021, surveys were conducted by NSB. The primary goal of the project, also known as BWASP through 2010, ASAMM from 2011 to 2019, and NSB Autumn Aerial Surveys in 2020 and 2021, was to document bowhead whales (Balaena mysticetus) during their fall migration through the western Beaufort Sea, although data were also collected for all other marine mammals that were sighted during the surveys. The surveys were typically conducted during the months of September and October, when offshore drilling and geophysical exploration are feasible and when the fall subsistence hunt for bowhead whales takes place near Kaktovik, Cross Island (village of Nuiqsut), and Utqiaġvik (formerly Barrow), Alaska. Additional surveys were conducted in the Beaufort Sea during spring and summer 1979-1986, and during summer 2011 to 2019, and from approximately 15 September to 15 October 2020 to 2021. EASTERN CHUKCHI SEA Aerial surveys in the eastern Chukchi Sea (68-73 degrees N, 157-169 degrees W) were conducted by MMS (now BOEM) contractors from 1982 to 1991. From 2008 to 2019, the surveys were conducted by MML. In 2020 and 2021, the surveys were conducted by NSB in collaboration with CICOES and MML and used a similar methodology to the surveys conducted in previous years. Starting in 2014, surveys were expanded south to 67 degrees N. The goal of the surveys, also known as the Chukchi Offshore Monitoring in Drilling Area (COMIDA) through 2010, ASAMM from 2011 to 2019, and NSB surveys in 2020 and 2021, was to investigate the distribution and relative abundance of marine mammals in the Chukchi Sea Planning Area (CSPA) during the open water (i.e., ice-free) months of June to October, when various species are undertaking seasonal migrations through the area. However, from 1979 to 1984, surveys were also conducted during spring. In 2020 and 2021, NSB Autumn Aerial Surveys in the Chukchi Sea from approximately 15 September to 15 October, were prioritized only when weather conditions were not conducive to surveying the western Beaufort Sea. NORTHERN BERING AND SOUTHERN CHUKCHI SEAS Aerial surveys in the northern Bering and southern Chukchi seas (63-68 degrees N, east of the International Date Line) were conducted by MMS (now BOEM) contractors from 1979 to 1985. The goal of these surveys was to investigate the distribution, abundance, migration timing, habitat relationships and behavior of endangered whales during the spring migration. Surveys were conducted from April to July. EASTERN BEAUFORT SEA AND AMUNDSEN GULF Aerial surveys in the eastern Beaufort Sea and Amundsen Gulf (67-73 degrees N, 118-140 degrees W), were conducted by MML from 5 to 27 August 2019, in collaboration with BOEM, NSB, Department of Fisheries and Oceans Canada, Inuvialuit Game Council, and Fisheries Joint Management Committee. The goal of these surveys, known as the ASAMM Bowhead Abundance (ABA) project, was to collect aerial survey data specific to estimating the abundance of the Bering-Chukchi-Beaufort Seas bowhead whale population. The primary ABA study area in its entirety includes the Beaufort Sea shelf and Amundsen Gulf (118-158 degrees W). This dataset is available to the public for a wide variety of uses including scientific research and analysis. completed historicalArchive NOAA National Centers for Environmental Information ncei.info@noaa.gov https://www.ncei.noaa.gov/contact HTTPS NCEI Contact Information Information for contacts at NCEI. information pointOfContact asNeeded NCEI Accession 0039614 was revised and a new version of the archival package was published. Updates to existing archival packages may provide additional files or replace obsolete files. The latest version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. Please see journal.txt in the /about directory for additional details on changes made. https://www.ncei.noaa.gov/access/metadata/landing-page/bin/gfx?id=gov.noaa.nodc:0039614 Preview graphic PNG 0039614 NCEI ACCESSION NUMBER 2021-08-24 publication ANIMALS - GROUP - BEHAVIOR ANIMALS - GROUP - NUMBER IN GROUP ANIMALS - INDIVIDUAL ANIMALS - INDIVIDUAL - BEHAVIOR ANIMALS - INDIVIDUAL - COUNTS cetacean dolphins ICE MARINE MAMMALS pinnipeds species abundance SPECIES IDENTIFICATION TERRESTRIAL MAMMALS theme NODC DATA TYPES THESAURUS GPS inclinometer line transect sampling visual observation instrument NODC INSTRUMENT TYPES THESAURUS biological marine mammal observation survey survey - biological visual estimate visual observation theme NODC OBSERVATION TYPES THESAURUS AIRCRAFT platform NODC PLATFORM NAMES THESAURUS Bureau of Ocean Energy Management Bureau of Ocean Energy Management, Regulation and Enforcement NOAA Alaska Fisheries Science Center, Marine Mammal Laboratory US Minerals Management Service dataCentre NODC COLLECTING INSTITUTION NAMES THESAURUS NOAA Alaska Fisheries Science Center dataCentre NODC SUBMITTING INSTITUTION NAMES THESAURUS Aerial Surveys of Arctic Marine Mammals (ASAMM) BOWHEAD WHALE AERIAL SURVEY PROJECT (BWASP) project NODC PROJECT NAMES THESAURUS Arctic Ocean Beaufort Sea Bering Sea Chukchi Sea Gulf of Alaska Northwestern Passages place NODC SEA AREA NAMES THESAURUS oceanography theme WMO_CategoryCode 2012-09-15 publication DOC/NOAA/NESDIS/NODC > National Oceanographic Data Center, NESDIS, NOAA, U.S. Department of Commerce DOC/NOAA/NMFS/AFSC > Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, U.S. Department of Commerce DOC/NOAA/NMFS/AFSC/MML > Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, U.S. Department of Commerce DOI/BOEM dataCentre Global Change Master Directory (GCMD) Data Center Keywords 2026 revision 24 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian ASAMM Bowhead Abundance (ABA) Chukchi Sea Offshore Monitoring in Drilling Area (COMIDA) North Slope Borough bowhead whale aerial surveys (NSB surveys) project Originator Project Keyword EARTH SCIENCE > AGRICULTURE > ANIMAL SCIENCE > ANIMAL ECOLOGY AND BEHAVIOR EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > MAMMALS EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > MAMMALS > CETACEANS EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > MARINE MAMMALS EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > MARINE MAMMALS > DOLPHINS EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > MARINE MAMMALS > PINNIPED EARTH SCIENCE > OCEANS > SEA ICE theme Global Change Master Directory (GCMD) Science Keywords 2026 revision 24 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian Dall sheep Dall's porpoise abundance aerial survey arctic fox bearded seal beluga bowhead whale brown bear caribou distribution fin whale gray whale gray wolf habitat harbor porpoise humpback whale kill site no bear killer whale line-transect survey minke whale musk ox polar bear ribbon seal right whale ringed seal shark spotted seal walrus theme Originator Keywords GPS RECEIVERS > GPS RECEIVERS INCLINOMETERS > INCLINOMETERS Line Transect Sampling VISUAL OBSERVATIONS > VISUAL OBSERVATIONS instrument Global Change Master Directory (GCMD) Instrument Keywords 2026 revision 24 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian OCEAN > ARCTIC OCEAN OCEAN > ARCTIC OCEAN > BEAUFORT SEA OCEAN > ARCTIC OCEAN > CHUKCHI SEA OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN > BERING SEA OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN > GULF OF ALASKA place Global Change Master Directory (GCMD) Location Keywords 2026 revision 24 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian Alaska Amundsen Gulf Arctic Beaufort Sea Bering Sea Chukchi Sea place Originator Place Names fall spring summer temporal Originator Temporal Keywords 02KFKW Send2NCEI Submission Package ID accessLevel: public otherRestrictions Cite as: BOEM, Alaska Outer Continental Shelf (OCS) Region; NOAA, National Marine Fisheries Service, Alaska Fisheries Science Center; North Slope Borough (2008). Aerial Surveys of Arctic Marine Mammals (ASAMM) collected by Marine Mammal Laboratory, Bureau of Ocean Energy Management, and other agencies in the Bering, Chukchi, Beaufort Seas, and Amundsen Gulf from 1979 to 2019 and North Slope Borough, Alaska from 2020 to 2021 (NCEI Accession 0039614). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.7289/v51v5bzm. Accessed [date]. Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives. otherRestrictions Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose. eng; USA utf8 environment oceans biota -174.01 -115.0671 57.73 76.15 1979-04-21 2021-10-10 In this accession, NCEI has archived multiple versions of these data. The latest (and best) version of these data has the largest version number. NOAA National Centers for Environmental Information +1-301-713-3277 ncei.info@noaa.gov pointOfContact In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media. Contact NCEI for other distribution options and instructions. ACCDB CSV MDB Word Shapefile 661.008 https://doi.org/10.7289/v51v5bzm HTTPS Web browser NCEI Dataset Landing Page Navigate directly to the URL for a descriptive web page with download links. information https://www.ncei.noaa.gov/archive/accession/oas/39614 HTTPS Web browser Descriptive Information Navigate directly to the URL for a descriptive web page with download links. information https://www.ncei.noaa.gov/archive/accession/download/39614 HTTPS Web browser HTTPS Navigate directly to the URL for data access and direct download. download ftp://ftp-oceans.ncei.noaa.gov/nodc/archive/arc0020/0039614/ FTP Any FTP client FTP These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). download dataset NCEI Accession 0039614 v1.1 was published. 2008-03-12T10:55:56Z NCEI Accession 0039614 v1.1 publication https://www.ncei.noaa.gov/archive/accession/0039614/1.1 HTTPS NCEI Accession 0039614 v1.1 published 2008-03-12T10:55:56Z download NCEI Accession 0039614 was revised and v2.2 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2012-07-25T22:32:34Z NCEI Accession 0039614 v2.2 publication https://www.ncei.noaa.gov/archive/accession/0039614/2.2 HTTPS NCEI Accession 0039614 v2.2 published 2012-07-25T22:32:34Z download NCEI Accession 0039614 was revised and v3.3 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2014-03-17T11:11:55Z NCEI Accession 0039614 v3.3 publication https://www.ncei.noaa.gov/archive/accession/0039614/3.3 HTTPS NCEI Accession 0039614 v3.3 published 2014-03-17T11:11:55Z download NCEI Accession 0039614 was revised and v4.4 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2015-05-06T11:34:55Z NCEI Accession 0039614 v4.4 publication https://www.ncei.noaa.gov/archive/accession/0039614/4.4 HTTPS NCEI Accession 0039614 v4.4 published 2015-05-06T11:34:55Z download NCEI Accession 0039614 was revised and v5.5 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2016-04-07T19:08:59Z NCEI Accession 0039614 v5.5 publication https://www.ncei.noaa.gov/archive/accession/0039614/5.5 HTTPS NCEI Accession 0039614 v5.5 published 2016-04-07T19:08:59Z download NCEI Accession 0039614 was revised and v6.6 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2017-03-28T17:06:10Z NCEI Accession 0039614 v6.6 publication https://www.ncei.noaa.gov/archive/accession/0039614/6.6 HTTPS NCEI Accession 0039614 v6.6 published 2017-03-28T17:06:10Z download NCEI Accession 0039614 was revised and v7.7 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2018-11-28T13:25:53Z NCEI Accession 0039614 v7.7 publication https://www.ncei.noaa.gov/archive/accession/0039614/7.7 HTTPS NCEI Accession 0039614 v7.7 published 2018-11-28T13:25:53Z download NCEI Accession 0039614 was revised and v8.8 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2019-04-08T16:27:54Z NCEI Accession 0039614 v8.8 publication https://www.ncei.noaa.gov/archive/accession/0039614/8.8 HTTPS NCEI Accession 0039614 v8.8 published 2019-04-08T16:27:54Z download NCEI Accession 0039614 was revised and v9.9 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2020-12-24T11:36:13Z NCEI Accession 0039614 v9.9 publication https://www.ncei.noaa.gov/archive/accession/0039614/9.9 HTTPS NCEI Accession 0039614 v9.9 published 2020-12-24T11:36:13Z download NCEI Accession 0039614 was revised and v10.10 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2021-09-03T17:12:00Z NCEI Accession 0039614 v10.10 publication https://www.ncei.noaa.gov/archive/accession/0039614/10.10 HTTPS NCEI Accession 0039614 v10.10 published 2021-09-03T17:12:00Z download NCEI Accession 0039614 was revised and v11.11 was published. Updates were received for this dataset. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession. 2022-05-31T19:06:35Z NCEI Accession 0039614 v11.11 publication https://www.ncei.noaa.gov/archive/accession/0039614/11.11 HTTPS NCEI Accession 0039614 v11.11 published 2022-05-31T19:06:35Z download repository NOAA National Centers for Environmental Information NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015. 2015-04-22T00:00:00 asNeeded Metadata are developed, maintained and distributed by NCEI. Updates are performed as needed to maintain currentness. NOAA National Centers for Environmental Information custodian GPS GPS Global Positioning System receiver satellite-based instrument used for geo-location, positioning and navigation inclinometer inclinometer used on moored buoys to derive wave steepness or height instrument used on moored buoys to measure 'vertical displacement of the buoy hull' to determine wave height, period, etc. May be used in conjunction with the use of a Datawell Hippy sensor to measure vertical heave acceleration along with pitch and roll. Also may be used with a second sensor, a triaxial magnetometer, is used to measure hull azimuth. line transect sampling line transect sampling perpendicular distances from a line A line is traversed by an observer and perpendicular distances are measured from the line to each detected object. Reference https://distancesampling.org/downloads/distancebook1993/index.html; Buckland, S.T., Anderson, D.R., Burnham, K.P. and Laake, J.L. 1993. Distance Sampling: Estimating Abundance of Biological Populations. Chapman and Hall, London. 446pp. visual observation visual observation not an instrument - maybe an observation type AIRCRAFT AIRCRAFT