AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service Annual Eastern Bering Sea Summer Bottom Trawl Surveys 1975 - 2018

Metadata Updated: February 27, 2019

This dataset contains detailed crab data collected from the annual NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the eastern Bering Sea continental shelf. The standard survey area, surveyed each year since 1975, encompasses a major portion of the eastern Bering Sea shelf between the 20 meter and 200 meter isobaths and from the Alaska Peninsula to the north of St. Matthew Island. The study area is divided into a grid with cell sizes of 20 x 20 nautical miles (37 x 37 kilometers). Sampling takes place within each 20 x 20 nautical mile grid cell. In areas surrounding St. Matthew (1983-present) and the Pribilof Islands (1981-present), grid corners were also sampled to better assess king crab concentrations. In 1975, tows were 1 hour in duration; from 1976 to present, each tow is one-half hour in duration, averaging 1.54 nautical miles (2.86 kilometers) - exact tow duration and distance fished for each haul can be found in RACEBASE.HAUL. 100% of the catch is sorted for red, blue, and golden king crab, bairdi Tanner, snow crab, hybrid Tanner, and hair crab. 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.

Access & Use Information

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Dates

Metadata Date November 28, 2018
Metadata Created Date May 31, 2016
Metadata Updated Date February 27, 2019
Reference Date(s) (publication)
Frequency Of Update annually

Metadata Source

Harvested from NOAA CSW Harvest Source

Additional Metadata

Resource Type Dataset
Metadata Date November 28, 2018
Metadata Created Date May 31, 2016
Metadata Updated Date February 27, 2019
Reference Date(s) (publication)
Responsible Party (Point of Contact, Custodian)
Contact Email
Access Constraints Access Constraints: There are no legal restrictions on access to the data. They reside in public domain and can be freely distributed. | 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 is designed as a systematic survey. Any data analysis must take into consideration the survey design for the results to be valid. The exact location of the trawl within the 20 x 20 nautical mile grid varies each year. In some cases, a tow will originate in one station and conclude in another. The data user may need to define set criteria for tow location from year to year. In addition, higher station density in the Pribilof (1981 to present) and St. Matthew Island (1983 to present) regions necessitate defining criteria for assigning data to grid cells to avoid biased population indices. This dataset includes data obtained from non-standard (special project, opportunistic collections, hot spot tows, 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. | 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.
Bbox East Long -157.97861
Bbox North Lat 68.3
Bbox South Lat 53.81867
Bbox West Long -178.74067
Coupled Resource
Frequency Of Update annually
Guid gov.noaa.nmfs.inport:17108
Harvest Object Id e787573f-af07-4a7f-87dc-b75e4fc99a06
Harvest Source Id 2aed8e29-fc5b-4cde-aa66-fb1118fd705e
Harvest Source Title NOAA CSW Harvest Source
Licence 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.
Metadata Language eng
Metadata Type geospatial
Progress underDevelopment
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 1975-06
Temporal Extent End 2015-08

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