gov.noaa.nmfs.inport:23470 eng UTF8 dataset CSV Files Alaska Fisheries Science Center 7600 Sand Point Way N.E., Building 4 Seattle WA 98115 USA https://www.afsc.noaa.gov WWW:LINK-1.0-http--link Website Website for this organization information 0700-1700 Pacific Time resourceProvider Armistead, Claire 907 481 1730 claire.armistead@noaa.gov claire.armistead@noaa.gov pointOfContact 2026-03-04T19:17:17 ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for imagery and gridded data ISO 19115-2:2009(E) AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service 2012 Chukchi Sea Bottom Trawl Surveys AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service 2012 Chukchi Sea Bottom Trawl Surveys publication NOAA/NMFS/EDM 23470 https://www.fisheries.noaa.gov/inport/item/23470 WWW:LINK-1.0-http--link Full Metadata Record View the complete metadata record on InPort for more information about this dataset. information Alaska Fisheries Science Center (206) 526-4000 (206) 526-4004 7600 Sand Point Way N.E., Building 4 Seattle WA 98115 USA afsc.webmaster@noaa.gov https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center WWW:LINK-1.0-http--link Alaska Fisheries Science Center Website AKFSC Home Page information 0700-1700 Pacific Time originator https://www.afsc.noaa.gov/Publications/AFSC-TM/NOAA-TM-AFSC-278.pdf WWW:LINK-1.0-http--link Citation URL AFSC Technical Memorandum summarizing results of the 2012 Chukchi Sea bottom trawl survey of bottomfishes, crabs, and other demersal macrofauna download https://www.afsc.noaa.gov/RACE/groundfish/species_codebook.pdf WWW:LINK-1.0-http--link Citation URL Listing of codes used for fish and invertebrates identified in RACE Division surveys download tableDigital This dataset contains detailed crab data collected from the 2012 NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the Chukchi Sea. 71 survey stations were successfully completed during the bottom trawl survey. The survey area extended north and east from the Bering Strait to Barrow Canyon, bounded to the west by the U.S.-Russia Maritime Boundary and east to the 10-m bathymetry limit along the Alaska coastline. Demersal populations were sampled by trawling at stations centered within 55.56 x 55.56 km (30 x 30 nautical miles) grid cells covering the survey area. 100% of the catch is sorted for commercially important crab species. Crabs are sorted by species and sex, and a sample is measured to the nearest millimeter to provide a size-frequency distribution (see note under use constraints for analyzing catches where crab were subsampled for measurement). Carapace width is measured for Tanner crabs, and carapace length is measured for king and hair crabs. Provide crab data from the 2012 bottom trawl survey of the Chukchi Sea. completed Foy, Robert robert.foy@noaa.gov pointOfContact Armistead, Claire 907 481 1730 claire.armistead@noaa.gov claire.armistead@noaa.gov custodian annually fall summer temporal Alaska Chukchi Sea place 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 2017-04-24 publication 8.5 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 22. 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 Shellfish Assessment Program project InPort otherRestrictions Cite As: Alaska Fisheries Science Center, [Date of Access]: AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service 2012 Chukchi Sea Bottom Trawl Surveys [Data Date Range], https://www.fisheries.noaa.gov/inport/item/23470. NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose. otherRestrictions Access Constraints: There are no legal restrictions on access to the data. They reside in public domain and can be freely distributed. otherRestrictions Use Constraints: Population size estimates make the assumption that 100% of the species within the path of the trawl are captured. In fact, the situation is more complex. As with any fishing gear, the survey trawl exhibits some size selectivity. Some crab may escape under the footrope of the net. Survey abundance estimates are probably best seen as relative measures of abundance. This survey was designed as a systematic survey based on a 55.6 km (30 nautical mile (nmi)) square grid pattern with the planned trawl stations located at the approximate center of each grid cell. Any data analysis must take into consideration the survey design for the results to be valid. This dataset includes data obtained from non-standard (special project, beam trawl,opportunistic collections, etc.) tows, and data that may have been collected from poor performance tows. Note that, while 100% of the total catch is sorted for all commercially important crab species, it may not be possible to measure all crabs. This is noted in the SAMPLING_FACTOR data field: a sampling factor of 1 indicates that all crab were measured; a sampling factor > 1 indicates that crabs were subsampled for measurement. To calculate the total number of crab caught by haul, sum the sampling_factor. This database should not be copied or distributed without its associated metadata file. User must read and fully comprehend the metadata prior to use. Use of these data is not restricted; however, organizations, agencies, units of government, or other users are responsible for the appropriate application of these data. Acknowledgement of NOAA/NMFS/AFSC ,as the source from which these data were obtained, in any publications and/or other representations of these data is suggested. otherRestrictions Distribution Liability: The user is responsible for the results of any application of this data for other than its intended purpose.NOAA denies liability if the data are misused. unclassified NOAA Data Management Plan (DMP) NOAA/NMFS/EDM 23470 https://www.fisheries.noaa.gov/inportserve/waf/noaa/nmfs/afsc/dmp/pdf/23470.pdf WWW:LINK-1.0-http--link NOAA Data Management Plan (DMP) NOAA Data Management Plan for this record on InPort. information crossReference eng; US biota oceans Oracle -168.58 -157.17 66 73.05 More elaborate than a keyword. | Currentness: Ground Condition 2012-08-01 2012-09-01 Funding for this survey was provided in part by the Bureau of Ocean Energy Management (BOEM) Arctic Ecosystem Integrated Survey (Arctic Eis) contract agreement number M12PG00018. Survey efforts were conducted aboard the 43.5 m FV Alaska Knight, a twin-engine, houseforward, commercial stern trawler with Kort nozzles allowing for suitable control of the vessel at slow trawling speeds (3.0 knots). The bottom trawl used for sampling was an 83-112 Eastern trawl, which has a 25.3 m (83 ft) headrope and a 34.1 m (112 ft) footrope. Survey trawls were towed behind 816 kg, 1.8 x 2.7 m, steel V-doors and 54.9 m (30 fathoms) paired bridles. Each lower bridle had a 61 cm chain extension connected to the lower wing edge to improve bottom-tending characteristics. The footrope was fished without roller gear and consisted of a wrapped 0.8 cm (5/16 in.) chain to maximize bottom contact. The body of the net was constructed from nylon with stretched mesh sizes 10.2 cm (4 in.) in the wings and body and 8.9 cm (3.5 in.) in the intermediate and codend. The codend also had a liner of 3.2 cm (1.25 in.) mesh. Samples were collected by bottom trawling at each station for a target fishing time of 15 minutes at a speed of 1.54 msec-1 (3 knots). When possible, the tow was conducted near the center of a 55.6 x 55.6 km grid cell, and the vessel maintained a constant heading during the tow. Note that, while 100% of the total catch is sorted for all commercially important crab species, it may not be possible to measure all crabs. This is noted in the SAMPLING_FACTOR data field: a sampling factor of 1 indicates that all crab were measured; a sampling factor greater than 1 indicates that crabs were subsampled for measurement. To calculate the total number of crab caught by haul, sum the sampling_factor. false eng false EBSCRAB 2016-05-16 publication Foy, Robert robert.foy@noaa.gov robert.foy@noaa.gov distributor https://www.afsc.noaa.gov/Publications/AFSC-TM/NOAA-TM-AFSC-278.pdf WWW:LINK-1.0-http--link https://www.afsc.noaa.gov/Publications/AFSC-TM/NOAA-TM-AFSC-278.pdf AFSC Technical Memorandum summarizing results of the 2012 Chukchi Sea bottom trawl survey of bottomfishes, crabs, and other demersal macrofauna download https://www.afsc.noaa.gov/RACE/groundfish/species_codebook.pdf WWW:LINK-1.0-http--link https://www.afsc.noaa.gov/RACE/groundfish/species_codebook.pdf Listing of codes used for fish and invertebrates identified in RACE Division surveys download dataset Completeness Measure Population size estimates make the assumption that 100% of the species within the path of the trawl are captured. In fact, the situation is more complex. As with any fishing gear, the survey trawl exhibits some size selectivity. Some crab may escape under the footrope of the net. Survey abundance estimates are probably best seen as relative measures of abundance. This survey was designed as a systematic survey based on a 55.6 km (30 nautical mile (nmi)) square grid pattern with the planned trawl stations located at the approximate center of each grid cell. Any data analysis must take into consideration the survey design for the results to be valid. This dataset includes data obtained from non-standard (special project, beam trawl,opportunistic collections, etc.) tows, and data that may have been collected from poor performance tows. Note that, while 100% of the total catch is sorted for all commercially important crab species, it may not be possible to measure all crabs. This is noted in the SAMPLING_FACTOR data field: a sampling factor of 1 indicates that all crab were measured; a sampling factor > 1 indicates that crabs were subsampled for measurement. To calculate the total number of crab caught by haul, sum the sampling_factor. Completeness Report Data set includes data collected from standard and non-standard hauls (special projects, opportunistic collections, etc.). Users of this dataset should be familiar with the haul type codes used in RACEBASE.HAUL (linked to CRAB.EBSCRAB via hauljoin field) before performing analyses Conceptual Consistency Data is checked for values outside range unknown All crab were removed from the catch, sorted by species and sex, and a total catch weight was obtained for each species. Tanner and snow crab hybrids are identified by a combination of characteristics including curve of the epistome margin, eye color, carapace shape, and space between or shape of the rostrum horns. A random subsample of the total catch occurred when an exceptionally large number (> 300) of a species was caught in a tow. The subsample varies in size and composition depending on the particular tow. The subsample may have occurred at the level of the entire catch or at the level of a particular size and sex category once the catch was sorted. The total weights of the sampled crab and non-sampled crab were recorded and an expansion factor was calculated to determine the final number of each species in the catch. Individual crab carapaces were measured (± 1 mm) to provide a size-frequency distribution of each sample. Crab sizes are reported as carapace width (CW) excluding spines for Tanner and snow crab, and carapace length (CL) for all king crab and hair crab. In the absence of specific age data, shell condition classification by length and sex is necessary for apportioning stock abundance and biomass for determination of stock status, analytical stock assessment, and for establishing annual management controls. Shell condition class serves as a semi-quantitative index of molt status and time in shell post-molt. For all EBS crab stocks, and particularly those which exhibit a terminal molt at maturity (i.e., Chionoecetes spp.), shell condition is a requisite for setting overfishing limits and harvest quotas. Carapace shell condition was assessed for each crab sampled and assigned to one of six classes according to specific criteria (0 = premolt or molting, 1 = soft and pliable, 2 = new hardshell both firm and clean, 3 = oldshell slightly worn, 4 = oldshell worn, 5 = very oldshell). Clutch assessment is used to estimate spawning stock biomass and overall reproductive health and to monitor demographic changes in the mating population. All female crab abdomens were evaluated to determine reproductive condition based on the color of the eggs (0 = no eggs, 2 = purple, 3 = brown, 4 = orange, 5 = purple-brown, 6 = pink), the condition of the eggs (0 = no eggs, 1 = uneyed, 2 = eyed, 3 = dead, 4 = empty egg cases), and the size of the egg clutch (0 = immature, 1 = mature female no eggs, 2 = trace to 1/8, 3 = 1/4, 4 = 1/2, 5 = 3/4, 6 = full). For mature females, egg clutch and egg condition codes were used to identify the stage in the molt-mate cycle, where the presence of eyed embryos, empty egg cases, or absence of eggs (barren, hereafter) in mature-sized females were indications of an incomplete cycle while mature females brooding uneyed embryos indicated completion of the cycle. Catch-per-unit-effort CPUE), abundance, and biomass estimates are calculated by species and by stock. Area swept is calculated as the product of the distance trawled while the net had bottom contact by the mean net width over the duration of the tow. CPUE is expressed in terms of number (or weight) of crab per square nautical mile. Biomass estimates are calculated for the number of individual male and female crab species at each 1 mm size category using the weight-size relationships developed by the AFSC’s Kodiak Laboratory. The size-weight relationships are described by the expression: W = a Lb, where W is the total weight in grams, L is either CL or CW in millimeters, a is the intercept in log scale and b is the slope. Parameters a and b for the size-weight relationships are estimated from a linear regression fitted to log-transformed size-weight data. The weights calculated at each 1 mm size category are summed within the legal male, sublegal male, mature and immature size categories for each species and sex caught at a station. The crab biomass within a district or section stratum was estimated by averaging crab densities from all stations within the defined district or section stratum and multiplied by the total area of the district or section stratum specific to that stock. Total biomass was calculated using a stratified design based on management units (standard density, high density, Alaska Department of Fish&Game-defined districts, or section stratum). Population biomass estimates were calculated in each stratum and then summed among strata. Variance of the total biomass estimate for each size class was calculated by summing the variance of each stratum. The 95% confidence intervals were calculated using the standard error of the total population multiplied by 1.96.