gov.noaa.nodc:NMFS-AFSC-EFH-AK eng utf8 series 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 2026-04-08T15:22:57Z ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) NOAA Fisheries Alaska Essential Fish Habitat and Supplemental Habitat Datasets 2024-02-01 publication 2025-12-04 revision 2024-01-19 creation International DOI Foundation (IDF) 10.25921/dv90-m778 NOAA National Centers for Environmental Information gov.noaa.nodc:NMFS-AFSC-EFH-AK 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 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 NOAA Fisheries Alaska Regional Office (NMFS/ARO) https://www.fisheries.noaa.gov/about/alaska-regional-office HTTPS NOAA Fisheries Alaska Regional Office (NMFS/ARO) website Institution web page information resourceProvider Charlene Felkley NOAA Fisheries Alaska Regional Office (NMFS/ARO) nmfs.akr.habitat@noaa.gov https://www.fisheries.noaa.gov/about/alaska-regional-office HTTPS NOAA Fisheries Alaska Regional Office (NMFS/ARO) website Institution web page information pointOfContact National Marine Fisheries Service Alaska Regional Office https://www.fisheries.noaa.gov/about/alaska-regional-office HTTPS NOAA Fisheries Alaska Regional Office (NMFS/ARO) website Institution web page information author NOAA Fisheries (NMFS) https://www.fisheries.noaa.gov/ HTTPS NOAA Fisheries (NMFS) website Institution web page information contributor tableDigital The Magnuson-Stevens Fishery Conservation and Management Act requires the description and identification of essential fish habitat (EFH) for species included in federal fishery management plans (FMPs). NMFS Alaska Region provides a collection with EFH maps, supporting data, and supplemental habitat datasets. Alaska EFH maps are developed by species’ life history stages within the spatial extent of the fishery management units of the FMPs. The data included varies by FMP, representing EFH based on species survey distribution maps developed through analysis of species distributions from fishery independent surveys and fishery observer data (Scallop FMP), cumulative frequency distribution model maps developed through analysis of species survey data and environmental covariates (Salmon FMP), and species distribution model maps developed through analysis of species data from fishery independent surveys or fishery observer data and environmental covariates (Groundfish, Crab, and Arctic FMPs). The EFH mapping data available in this collection include GIS files (geodatabases, shapefiles, raster files) that are organized by FMP with supporting documents. The EFH maps and supporting data are updated with the completion of an EFH 5-year Review. One of the challenges for understanding EFH in Alaska’s nearshore is the extensive and complex coastline (~55,000 km) with a diversity of estuarine and marine habitats. Supplemental datasets in this collection are Alaska ShoreZone, Shore Station, and the Nearshore Fish Atlas of Alaska (NFAA). ShoreZone is an aerial imaging, coastal habitat classification and mapping system used to inventory alongshore and across-shore geomorphological and biological attributes of the shoreline. The georeferenced, oblique, low altitude aerial imagery is acquired during the lowest tides of the year and then used to classify habitat attributes into a searchable database. Alaska ShoreZone data in this collection include videos, video still images, photos, GIS files (geodatabase and shapefiles), data dictionary, protocol, and flight plans. Shore Station is a compilation of data collected during low tide surveys from hundreds of intertidal sites throughout coastal Alaska. Survey data include observed species, species assemblages, geomorphic features (e.g., sediment, substrate, bedform), beach length, slope, specific elevation profiles. Shore Station data in the collection include photos, GIS files (geodatabase and shapefiles), and supporting documentation. The NFAA is a centralized, relational database of nearshore fish surveys, providing data on the distribution, relative abundance, and habitat use of nearshore fishes in Alaska. This dataset includes numerous nearshore surveys collected by various agencies and organizations over the past several decades with different objectives and gear types (e.g., beach seines, purse seines, and trawls). NFAA data in the collection include photos, GIS files (geodatabase and shapefiles), and supporting documentation. Describe and map essential fish habitat (EFH) for managed species including life history stages in Alaska Fishery Management Plans for the 2018 EFH 5-year Review as required by the EFH provisions of the Magnuson-Stevens Fishery Management and Conservation Act. Funding Agency: NOAA National Marine Fisheries Service (NMFS) Funding Agency: NOAA National Marine Fisheries Service Alaska Regional Office Funding Agency: NOAA Alaska Fisheries Science Center (NMFS/AFSC) onGoing 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 https://www.ncei.noaa.gov/access/metadata/landing-page/bin/gfx?id=gov.noaa.nodc:NMFS-AFSC-EFH-AK Preview graphic PNG 0287396 0292741 0304727 0307021 NCEI ACCESSION NUMBER 2025-05-02 publication biological data FISHERY SURVEY HABITAT images INDIVIDUAL FISH EXAMINATION - LENGTH SEDIMENTS species abundance SPECIES IDENTIFICATION WATER TEMPERATURE theme NODC DATA TYPES THESAURUS camera seine trawl instrument NODC INSTRUMENT TYPES THESAURUS aerial photography biological imagery in situ survey - biological theme NODC OBSERVATION TYPES THESAURUS NOAA Fisheries dataCentre NODC COLLECTING INSTITUTION NAMES THESAURUS NOAA Alaska Fisheries Science Center NOAA Fisheries Alaska Regional Office dataCentre NODC SUBMITTING INSTITUTION NAMES THESAURUS Arctic Ocean Beaufort Sea Bering Sea Bering Sea - Coastal Waters of Western Alaska Bering Sea - Norton Sound Chukchi Sea Chukchi Sea - NW Coast of Alaska Coastal Waters of Southeast Alaska and British Columbia Gulf of Alaska North Pacific Ocean Prince William Sound (Gulf of Alaska) place NODC SEA AREA NAMES THESAURUS oceanography theme WMO_CategoryCode 2012-09-15 publication DOC/NOAA/NMFS > National Marine Fisheries Service, NOAA, U.S. Department of Commerce DOC/NOAA/NMFS/AFSC > Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, U.S. Department of Commerce dataCentre Global Change Master Directory (GCMD) Data Center Keywords 2026 revision 23 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 EARTH SCIENCE > AGRICULTURE > AGRICULTURAL AQUATIC SCIENCES > FISHERIES EARTH SCIENCE > BIOLOGICAL CLASSIFICATION EARTH SCIENCE > OCEANS > MARINE SEDIMENTS EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > WATER TEMPERATURE theme Global Change Master Directory (GCMD) Science Keywords 2026 revision 23 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 Fish Atlas Photos Nearshore Fish Atlas: Combined results from multiple nearshore biological surveys, reporting. ShoreZone: Coastal Habitat Mapping Program capturing geomorphic and biological attributes of Alaska's coastline, surveyed at low The Alaska Shore Station Database is a compilation of data collected since 2002 during low tide surveys from hundreds of interti area of occupied habitat theme Provider Keywords Analyzed Aerial Photography and video nets (e.g. beach seine, trawl-bottom) survey samples theme Provider Observation Categories CAMERA > CAMERA NETS > NETS TRAWL instrument Global Change Master Directory (GCMD) Instrument Keywords 2026 revision 23 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 commercial scallop gear Low tide, oblique aerial imagery Multiple Gear types NOAA Technical Memorandum NMFS-AFSC-239 bottom trawl site survey surface trawl and purse seine instrument Provider Instruments OCEAN > ARCTIC OCEAN OCEAN > ARCTIC OCEAN > BEAUFORT SEA OCEAN > ARCTIC OCEAN > CHUKCHI SEA OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN 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 23 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 Arctic Ocean Bering Sea Chukchi Sea Coastal Waterways of Southeast Alaska and British Columbia Gulf of Alaska North Pacific Ocean Prince William Sound place Provider Place Names 3JGFJ3 9GLTLP EDJACN KB7GN5 Send2NCEI Submission Package ID accessLevel: public otherRestrictions Cite as: National Marine Fisheries Service Alaska Regional Office (2024). NOAA Fisheries Alaska Essential Fish Habitat and Supplemental Habitat Datasets. [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.25921/dv90-m778. 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. license Some of the data in this dataset has been dedicated to the public domain under a Creative Commons CC0 1.0 Universal (CC0 1.0) Public Domain Dedication. SPDX License: Creative Commons Zero v1.0 Universal (CC0-1.0) Laman, E. A., Rooper, C. N., Rooney, S. C., Turner, K. A. (Kali Alison), Cooper, D. W. (Daniel W.), & Zimmerman, Mark P., 1954-. (20 C.E.). Model-based essential fish habitat definitions for Bering Sea groundfish species. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center. https://doi.org/10.7289/v5/tm-afsc-357 1954 publication International DOI Foundation (IDF) https://doi.org/10.7289/v5/tm-afsc-357 https://doi.org/10.7289/v5/tm-afsc-357 HTTPS https://doi.org/10.7289/v5/tm-afsc-357 2018 EFH Review SDM EFH Tech Memos Bering Sea information Laman, Edward A. author Rooper, Christopher N. author Rooney, Sean Charles author Turner, K. A. (Kali Alison) author Cooper, D. W. (Daniel W.) author Zimmerman, Mark P., 1954- author U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center publisher documentDigital U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center crossReference sciencePaper Turner, K. A. (Kali Anderson), Rooper, C. N., Laman, E. A., Rooney, S. (Sean C.), Cooper, D. W. (Daniel W.), & Zimmermann, M. (Mark). (1 C.E.). Model-based essential fish habitat definitions for Aleutian Island groundfish species. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center. https://doi.org/10.7289/v5/tm-afsc-360 7289 publication International DOI Foundation (IDF) https://doi.org/10.7289/v5/tm-afsc-360 https://doi.org/10.7289/v5/tm-afsc-360 HTTPS https://doi.org/10.7289/v5/tm-afsc-360 2018 EFH Review SDM EFH Tech Memos Aleutian Islands information Turner, K. A. (Kali Anderson) author Rooper, Christopher N. author Laman, Edward A. author Rooney, S. (Sean C.) author Cooper, D. W. (Daniel W.) author Zimmermann, M. (Mark) author U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center publisher documentDigital U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center crossReference sciencePaper Rooney, S., Rooper, C. N., Laman, E., Turner, K., Cooper, D., & Zimmermann, M. (2 C.E.). Model-based essential fish habitat definitions for Gulf of Alaska groundfish species. U.S. Department of Commerce, National Oceanic and Atmopsheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center. https://doi.org/10.7289/v5/tm-afsc-373 7289 publication International DOI Foundation (IDF) https://doi.org/10.7289/v5/tm-afsc-373 https://doi.org/10.7289/v5/tm-afsc-373 HTTPS https://doi.org/10.7289/v5/tm-afsc-373 2018 EFH Review SDM EFH Tech Memos Gulf of Alaska information Rooney, S. author Rooper, C.N. author Laman, E. author Turner, K. author Cooper, D. author Zimmermann, M. author U.S. Department of Commerce, National Oceanic and Atmopsheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center publisher documentDigital U.S. Department of Commerce, National Oceanic and Atmopsheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center crossReference sciencePaper Echave, K. et al. (2012). A Refined Description of Essential Fish Habitat for Pacific Salmon Within the U.S. Exclusive Economic Zone in Alaska . https://apps-afsc.fisheries.noaa.gov/Publications/AFSC-TM/NOAA-TM-AFSC-236.pdf 2012 publication m NMFS-AFSC-236 https://apps-afsc.fisheries.noaa.gov/Publications/AFSC-TM/NOAA-TM-AFSC-236.pdf https://apps-afsc.fisheries.noaa.gov/Publications/AFSC-TM/NOAA-TM-AFSC-236.pdf HTTPS https://apps-afsc.fisheries.noaa.gov/Publications/AFSC-TM/NOAA-TM-AFSC-236.pdf A Refined Description of Essential Fish Habitat for Pacific Salmon Within the U.S. Exclusive Economic Zone in Alaska information Echave, K. author Eagleton, M. author Farley, E. author Orsi, J. author 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 publisher documentDigital NOAA Technical Memorandum 236 113 crossReference sciencePaper Laman, E. A. (2022). Advancing model-based essential fish habitat descriptions for North Pacific species in the Bering Sea. Alaska Fisheries Science Center (U.S.). https://doi.org/10.25923/y5gc-nk42 2022 publication International DOI Foundation (IDF) https://doi.org/10.25923/y5gc-nk42 https://doi.org/10.25923/y5gc-nk42 HTTPS https://doi.org/10.25923/y5gc-nk42 2023 EFH Review SDM EFH Tech Memos Bering Sea information Laman, E. A. author Alaska Fisheries Science Center (U.S.) publisher documentDigital Alaska Fisheries Science Center (U.S.) crossReference sciencePaper Harris, J. (2022). Advancing model-based essential fish habitat descriptions for North Pacific species in the Aleutian Islands. Alaska Fisheries Science Center (U.S.). https://doi.org/10.25923/ffnc-cg42 2022 publication International DOI Foundation (IDF) https://doi.org/10.25923/ffnc-cg42 https://doi.org/10.25923/ffnc-cg42 HTTPS https://doi.org/10.25923/ffnc-cg42 2023 EFH Review SDM EFH Tech Memos Aleutian Islands information Harris, J. author Alaska Fisheries Science Center (U.S.) publisher documentDigital Alaska Fisheries Science Center (U.S.) crossReference sciencePaper Pirtle, J. L. (2023). Advancing model-based essential fish habitat descriptions for North Pacific species in the Gulf of Alaska. Alaska Fisheries Science Center (U.S.). https://doi.org/10.25923/ygdf-5f65 2023 publication International DOI Foundation (IDF) https://doi.org/10.25923/ygdf-5f65 https://doi.org/10.25923/ygdf-5f65 HTTPS https://doi.org/10.25923/ygdf-5f65 2023 EFH Review SDM EFH Tech Memos Gulf of Alaska information Pirtle, J. L. author Alaska Fisheries Science Center (U.S.). publisher documentDigital Alaska Fisheries Science Center (U.S.). crossReference sciencePaper Marsh, J.M. et al. (2023). Model-Based Essential Fish Habitat Descriptions for Fish Resources of the Arctic Management Area. https://meetings.npfmc.org/CommentReview/DownloadFile?p=47fbbddc-1790-46bd-b1c1-ceff260d3a55.pdf&fileName=C4%20Arctic%20Marsh%20Advancing%20Model%20Based%20EFH.pdf 2023 publication C4 Arctic Marsh Model Based EFH https://meetings.npfmc.org/CommentReview/DownloadFile?p=47fbbddc-1790-46bd-b1c1-ceff260d3a55.pdf&fileName=C4%20Arctic%20Marsh%20Advancing%20Model%20Based%20EFH.pdf https://meetings.npfmc.org/CommentReview/DownloadFile?p=47fbbddc-1790-46bd-b1c1-ceff260d3a55.pdf&fileName=C4%20Arctic%20Marsh%20Advancing%20Model%20Based%20EFH.pdf HTTPS https://meetings.npfmc.org/CommentReview/DownloadFile?p=47fbbddc-1790-46bd-b1c1-ceff260d3a55.pdf&fileName=C4%20Arctic%20Marsh%20Advancing%20Model%20Based%20EFH.pdf Arctic Draft under agenda item C4 information Marsh, J.M. author Pirtle, J. L. author Mueter, F.J. author Harris, J. author North Pacific Fishery Management Council publisher documentDigital 86 crossReference sciencePaper Alaska Essential Fish Habitat Mapper https://www.fisheries.noaa.gov/resource/map/alaska-essential-fish-habitat-mapper 2023 publication https://www.fisheries.noaa.gov/resource/map/alaska-essential-fish-habitat-mapper https://www.fisheries.noaa.gov/resource/map/alaska-essential-fish-habitat-mapper HTTPS https://www.fisheries.noaa.gov/resource/map/alaska-essential-fish-habitat-mapper Alaska Essential Fish Habitat Mapper Landing Page information 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 publisher documentDigital crossReference program Alaska Essential Fish Habitat Mapping Application https://noaa.maps.arcgis.com/apps/webappviewer/index.html?id=66d51e1a1c34468bb766f6ec1b6f58d9 2023 publication https://noaa.maps.arcgis.com/apps/webappviewer/index.html?id=66d51e1a1c34468bb766f6ec1b6f58d9 https://noaa.maps.arcgis.com/apps/webappviewer/index.html?id=66d51e1a1c34468bb766f6ec1b6f58d9 HTTPS https://noaa.maps.arcgis.com/apps/webappviewer/index.html?id=66d51e1a1c34468bb766f6ec1b6f58d9 Alaska Essential Fish Habitat Mapper Application information Peacock, Noyuk author Millen, Chad author Lewis, Steve author Pirtle, Jodi author 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 publisher documentDigital crossReference project eng; USA utf8 environment oceans imageryBaseMapsEarthCover biota -175.00 -130.00 47.00 75.00 1964-01-01 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. Geodatabase Shapefile 16088.832 https://www.ncei.noaa.gov/oa/alaska-shore-zone/index.html#archive/ HTTPS Web browser NOAA NCEI Direct Download for Shore Zone Imagery and Video Navigate directly to the URL for data access and direct download. download https://doi.org/10.25921/dv90-m778 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/metadata/granule/geoportal/?from=0&size=10&esdsl=%7B%22query%22%3A%7B%22bool%22%3A%7B%22must%22%3A%5B%7B%22query_string%22%3A%7B%22analyze_wildcard%22%3Atrue%2C%22query%22%3A%22fileid%3ANMFS-AFSC-EFH-AK.*%22%7D%7D%5D%7D%7D%7D#searchPanel HTTPS Web browser Granule Search Search for data granules belonging to this collection (a granule is the smallest aggregation of data that can be independently described and retrieved). search series NCEI Accession 0287396 v1.1 was published. 2024-02-01T10:31:41Z NCEI Accession 0292741 v1.1 was published. 2024-05-31T19:56:43Z NCEI Accession 0304727 v1.1 was published. 2025-07-07T15:23:39Z NCEI Accession 0304727 was revised and v1.2 was published. 2025-08-07T14:10:32Z NCEI Accession 0307021 v1.1 was published. 2025-12-04T00:05:24Z asNeeded Metadata are developed, maintained and distributed by NCEI. Updates are performed as needed to maintain currentness. NOAA National Centers for Environmental Information custodian camera camera An instrument for recording images. seine seine a weighted net which collapses inward to trap fish trawl trawl A fishing net that is dragged behind a boat. A wide range of demersal (bottom) or pelagic (mid-water) species of fish are taken by this fishing method which entails one or a pair of vessels towing a large bag-shaped net either along the seafloor or in mid-water.