22956 AFSC/RACE/GAP/Palsson: GOA and AI Biennial Bottom Trawl Survey estimates of catch per unit effort, biomass, population at length, Data Set Published / External 22291 Groundfish Assessment Program Project In Work Unknown The GOA/AI Bottom Trawl Estimate database contains abundance estimates for the Alaska Biennial Bottom Trawl Surveys conducted in the Gulf of Alaska and the Aleutian Islands in alternate years. The estimates build upon raw and summary data available from the RACEBASE database and include calculated catch-per-unit-effort (cpue)s for principal species of groundfish and key invertebrates for each survey region. The cpues are averaged by survey strata, and then average cpues are multiplied by stratum areas which results in estimates of biomass and numerical abundance. Length and age data are combined with abundance to estimate the population at length and sex and population at age and sex. The cpues, biomass, and age and size composition estimates are used by NOAA Fisheries scientists in stock assessments of groundfish and invertebrate species managed by the North Pacific Fisheries Management Council. Loaded by FGDC Metadata Uploader, batch 5253, 12-23-2014 14:18 The following FGDC sections are not currently supported in InPort, but were preserved and will be included in the FGDC export: - Spatial Reference Information (FGDC:spref), - Spatial Data Organization Information (FGDC:spdoinfo) - Lineage (FGDC:lineage) Theme ISO 19115 Topic Category biota Theme ISO 19115 Topic Category oceans Spatial Alaska Spatial Aleutian Islands Spatial Gulf of Alaska Alaska Fisheries Science Center Seattle WA USA network\Oracle database and AKFIN Data Set Oracle Database As Needed Table (digital) http://www.akfin.org/ data derived from observational datasets, model outputs, etc. data derived from observational datasets, model outputs, etc. data derived from observational datasets, model outputs, etc. Data Steward 2015 Person Palsson, Wayne wayne.palsson@noaa.gov E-mail data steward Distributor 2015 Person Palsson, Wayne wayne.palsson@noaa.gov Metadata Contact 2015 Person Roberson, Nancy nancy.roberson@noaa.gov 7600 Sand Point Way NE Seattle WA 98115 USA Point of Contact 2015-11-30 Person Palsson, Wayne wayne.palsson@noaa.gov observed Gulf of Alaska and Aleutian Islands Continuing 1980 Biennial Restricted Must have a user account Go to the AKFIN website http://www.akfin.org/ and create a user account. "FISMA Controls are in place to protect stored data from unauthorized access and/or disclosure" http://www.akfin.org/ https://access.afsc.noaa.gov/data-zips/22956_RooperCTD.zip Zip Zip oracle tables not applicable unknown No Unknown No No Unknown NCEI-MD unknown "IT Security and Contingency Plan for the system establishes procedures and applies to the functions, operations, and resources necessary to recover and restore data as hosted in the Western Regional Support Center in Seattle, Washington, following a diserruption." NOAA’s Alaska Fisheries Science Center conducts the Alaska Biennial Bottom Trawl Survey of the Gulf of Alaska (GOA) and Aleutian Islands (AI) in alternate years. These surveys have been conducted since 1980 in the AI and since 1984 in the GOA and conform to NOAA Protocols for Groundfish Bottom Trawl Surveys of the Nation’s Fishery Resources (2004, G. Stauffer compiler, NOAA Technical Memorandum NMFS-SPO-65). The survey consists of three chartered commercial fishing vessels that tow a bottom trawl at randomly-selected stations stratified by region, depth, and in the case of the GOA, habitat. For the GOA survey, the sampling frame is known trawlable or new sites throughout the survey area, stratified by management areas; by shelf, slope, or gully habitats; and by depth zones including 0-100 m, 101-200 m, 201-300 m, 301-500 m, 501-700 m, and 701-1000 m (for GOA survey methodology, see von Szalay et al. 2010 Data Report: 2009 Gulf of Alaska Bottom Trawl Survey, NOAA Technical Memorandum NMFS-AFSC-208). For the AI survey, the sampling frame is past successfully towed stations, stratified by management region and the same GOA depth zones but only as deep as 500 m (for GOA survey methodology, see von Szalay et al. 2011. Data Report : 2010 Aleutian Islands Bottom Trawl Survey. NOAA Technical Memorandum NMFS-AFSC-215). At each station the research trawl is set for a targeted period of 15 min and if the tow is successful, the catch is processed. Catch processing includes identifying, counting, and weighing all living taxa, collecting length measurement for commercially and ecologically important groundfish and invertebrate species, and collecting other materials, such as age structure, for laboratory or other scientific analysis. For each tow, detailed data are collected about the characteristics of the sample including position, time, depth, surface and bottom temperatures, and net characteristics. Sensors on the net measure how the net is fishing, and we track the contact of the foot rope with the seafloor, the width of the net at the wing tips, and the height of the headrope. Tow-by-tow data are entered into computer databases or acquired electronically. Once the survey is completed, the data are error checked and finalized into a database known as RACEBASE. These data are further processed into estimates of abundance in terms of biomass and numbers of organisms. Estimates of abundance are based upon the area-swept technique whereby the catch per unit of effort (cpue) is computed for each successful station as the weight or count of each species divided by the area that the net contacted the seafloor during the tow. These calculated cpues are then averaged among the stations in each stratum and then multiplied by the calculated area of the stratum (as measured from digitized nautical charts and a geographic information system). The product of these terms is an estimate of the biomass or numerical abundance (see von Szalay et al. 2010 Data Report: 2009 Gulf of Alaska Bottom Trawl Survey, NOAA Technical Memorandum NMFS-AFSC-208 and von Szalay et al. 2011. Data Report : 2010 Aleutian Islands Bottom Trawl Survey. NOAA Technical Memorandum NMFS-AFSC-215 for more complete methods). The abundance estimates for the strata are combined by area-depth categories for convenient analysis. In addition, the population-at-length is estimate by applying length-sex frequency observations to the population abundance estimates. As age structures are evaluated for age determination, the population-at-size estimates are used with an age-length key to estimate the population-at-age structure of selected species. gov.noaa.nmfs.inport:22956 Nancy Roberson 2014-12-23T14:18:15 SysAdmin InPortAdmin 2023-08-15T17:09:51 2016-05-18 Alaska Fisheries Science Center AFSC 7600 Sand Point Way N.E., Building 4 Seattle WA 98115 USA https://www.afsc.noaa.gov 0700-1700 Pacific Time 1001 Public No No 2016-05-18 1 Year 2017-05-18 Raster Grid Cell 2328 2013 Albers Conical Equal Area 55.0 65.0 -154.0 50.0 0.0 0.0 coordinate pair 0.0000000030536018158500163 0.0000000030536018158500163 meters D North American 1983 GRS 1980 6378137.0 298.257222101 Mean lower low water 0.3 meters Explicit depth coordinate included with horizontal coordinates