17108
AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service Annual Eastern Bering Sea Summer Bottom Trawl Surveys 1975 - 2018
AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service Annual Eastern Bering Sea Summer Bottom Trawl Surveys 1975 - 2018
Data Set
Published / External
22354
Shellfish Assessment Program
Project
In Work
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.
Provide crab data from the annual bottom trawl survey of the eastern Bering Sea continental shelf.
Loaded by FGDC Metadata Uploader, batch 5412, 02-26-2015 12:34
The following FGDC sections are not currently supported in InPort, but were preserved and will be included in the FGDC export:
- Taxonomy (FGDC:taxonomy)
- Lineage (FGDC:lineage)
Survey vessels from 1975-1980 used a 400 mesh eastern otter trawl constructed of 36 thread 4-inch mesh in the wings, 60 thread 3-1/2 inch mesh in the intermediate, and 96 thread 1-1/4 inch mesh codend liner. The trawl was rigged with 18 eight-inch floats on the headrope and 25 fathom dandylines (10 fathom single, 15 fathom double). The footrope was 94 feet and the headrope was 71 feet in length. The doors were of the Astoria "V" type and measured 5 x 7 feet.. In 1981, one vessel (R/V Chapman) fished an 83-112 eastern otter trawl (described below), and the second vessel (R/V Alaska) fished the 400-mesh eastern otter trawl. From the 1982 survey to present, vessels have been equipped with 83-112 eastern otter trawls which have 25.3 meter (83 ft) headropes and 34.1 meter (112 ft) footropes. The footropes are 5/8 inch wire ropes wrapped with polypropylene ropes and heavy rubber hoses. Headropes contain 41- 8-inch floats. These nets are attached to tail chains with 54.9 meter (30 fathoms) paired bridles. Each lower bridle has a 0.61 meter chain extension connected to the lower wing edge to improve bottom tending characteristics. Steel "V"-doors measuring 1.8 x 2.7 meters and weighing 816 kilograms are used. The trawls are constructed of 3.5 and 4.0 inch polyethylene mesh with a 1.25 inch nylon liner in the codend. 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.
Theme
ISO 19115 Topic Category
biota
Theme
ISO 19115 Topic Category
oceans
Temporal
summer
Spatial
Alaska
Spatial
Bering Sea
Spatial
Chukchi Sea
Spatial
Norton Sound
Alaska Fisheries Science Center
Seattle
WA
USA
Data Set
Oracle Database
Annually
Table (digital)
RACE Shellfish Assessment Program eastern Bering Sea shelf crab database EBSCRAB
Refer to the pdf document Crab Code Instructions" provided with this dataset for a detailed descript
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.
Not Applicable
Not Applicable
Not Applicable
23469
EBSCRAB
EBSCRAB
Published / External
In Work
NA
Loaded by FGDC Metadata Uploader, batch 5412, 02-26-2015 12:34
Data Table
Yes
CRAB
NA
CRAB_ID
NUMBER
No
No
Active
Unique number generated by Oracle that identifies each record in the CRAB.EBSCRAB table
NA - NA
HAULJOIN
NUMBER
No
No
Active
NA
NA - NA
CRUISE
NUMBER
No
No
Active
6-digit number assigned to each RACE survey cruise; first 4 digits identify cruise year
NA - NA
VESSEL
NUMBER
No
No
Active
Numeric code assigned to each vessel participating in a RACE cruise (source: RACE ADP codebook)
NA - NA
HAUL
NUMBER
No
No
Active
Number identifying a specific tow
NA - NA
STATION
Unknown
No
No
Active
NA
unknown
SPECIES_CODE
NUMBER
No
No
Active
5-digit number assigned to a species (source: RACE ADP codebook)
NA - NA
SPECIES_KFRC
NUMBER
No
No
Active
Numeric code assigned to a species (source: NMFS Kodiak Shellfish Assessment Program)
NA - NA
SEX
VARCHAR2
No
No
Active
1-digit numeric code assigned to a particular sex of crab
1, 2, 3, 4
LENGTH
NUMBER
No
No
Active
Carapace measurement, in millimeters, of king and hair crabs
NA - NA
WIDTH
NUMBER
No
No
Active
Carapace measurement, in millimeters, of Chionoecetes and Dungeness crabs
NA - NA
SHELL_CONDITION
VARCHAR2
No
No
Active
1-digit numeric code describing carapace condition of crab
0, 1, 2, 3, 4, 5, 9
EGG_COLOR
VARCHAR2
No
No
Active
1-digit numeric code describing color of eggs in female crab
0, 2, 3, 4, 5, 6, 7, 9
EGG_CONDITION
VARCHAR2
No
No
Active
1-digit numeric code describing condition of eggs in female crab
0, 1, 2, 3, 4, 9
CLUTCH_SIZE
VARCHAR2
No
No
Active
1-digit numeric code describing fullness of clutch in female crab
0, 1, 2, 3, 4, 5, 6, 9
WEIGHT
NUMBER
No
No
Active
Weight, in grams, of individual crab
NA - NA
DISEASE_CODE
NUMBER
No
No
Active
1-digit numeric code indicating presence of certain diseases in crab
NA - NA
DISEASE_DORSAL
NUMBER
No
No
Active
If black mat disease is present, this 1-digit number describes percent of dorsal body surface covered by disease
NA - NA
DISEASE_VENTRAL
NUMBER
No
No
Active
If black mat disease is present, this 1-digit number describes percent of ventral body surface covered by disease
NA - NA
DISEASE_LEGS
NUMBER
No
No
Active
If black mat disease is present, this 1-digit number describes percent of leg surface covered by disease
NA - NA
SAMPLING_FACTOR
NUMBER
No
No
Active
NA
NA - NA
CHELA_HEIGHT
NUMBER
No
No
Active
Measurement, in millimeters, of height of right chela of crab
NA - NA
GIS_STATION
Unknown
No
No
Active
NA
unknown
COMMENTS
Unknown
No
No
Active
Any comments particular to that crab record or haul
unknown
Data Steward
2015-09-23
Person
Foy, Robert
robert.foy@noaa.gov
robert.foy@noaa.gov
Distributor
2015-02-26
Person
Foy, Robert
robert.foy@noaa.gov
robert.foy@noaa.gov
Metadata Contact
2015-02-26
Person
Lang, Christie
christie.lang@noaa.gov
christie.lang@noaa.gov
Originator
2015-02-26
Organization
Alaska Fisheries Science Center
AFSC
afsc.webmaster@noaa.gov
7600 Sand Point Way N.E., Building 4
Seattle
WA
98115
USA
(206) 526-4000
(206) 526-4004
https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
AKFSC Home Page
Online Resource
0700-1700 Pacific Time
Point of Contact
2015-02-26
Person
Foy, Robert
robert.foy@noaa.gov
Ground Condition
-178.74067
-157.97861
68.3
53.81867
More elaborate than a keyword.
Range
1975-06
2015-08
Unclassified
unknown
There are no legal restrictions on access to the data. They reside in public domain and can be freely distributed.
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.
https://console.cloud.google.com/storage/browser/_details/nmfs_odp_afsc/RACE/SAP/Detailed%20Crab%20Data%20From%20NOAA%20Fisheries%20Service%20Annual%20Eastern%20Bering%20Sea%20Summer%20Bottom%20Trawl%20Surveys%201975%20-%202018.csv
Note: Dataset migrated by Dan Woodrich (AFSC data management coordinator) on 12/14/2021. Contact: Daniel.woodrich@noaa.gov
http://www.afsc.noaa.gov/Publications/AFSC-TM/NOAA-TM-AFSC-308.pdf
Online Resource
pdf
AFSC Technical Memorandum summarizing results of the 2014 eastern Bering Sea trawl survey for commercially important crab species
http://www.afsc.noaa.gov/RACE/groundfish/species_codebook.pdf
Online Resource
pdf
Listing of codes used for fish and invertebrates identified in RACE Division surveys.
Oracle
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 (1980-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. 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.
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. 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. 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.
Data is checked for values outside range
Data is submitted through a thorough QA/QC process. Data is checked for outliers, impossible values, and invalid values.
No
Unknown
Yes
No
yes
unknown
No delay
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 disruption.
1
Trawl samples take place within 20 x 20 nautical mile grid cells throughout the eastern Bering Sea shelf. In areas surrounding St. Matthew (1983-present) and the Pribilof Islands (1980-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.
Organization
Alaska Fisheries Science Center
AFSC
afsc.webmaster@noaa.gov
7600 Sand Point Way N.E., Building 4
Seattle
WA
98115
USA
(206) 526-4000
(206) 526-4004
https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
AKFSC Home Page
Online Resource
0700-1700 Pacific Time
2
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. Since 2006, individual weights were measured for blue king crabs every year, red king crab and snow crab in odd years, and for Tanner crab in even years to add to the existing length-weight data and to monitor temporal variability in length-weight regressions. For every haul in 2014, data were collected on up to five intact crab per each of the following categories: 1) male
Tanner crab, 2) ovigerous Tanner crab, and 3) non-ovigerous female Tanner crab. Because of their relative rarity, weight data were collected for all intact blue king crabs encountered that met the sampling requirements (i.e., whole, live crab without regenerating limbs). Weights were collected from representative size ranges throughout the spatial distribution of each species.
Measurements were regionally stratified and tally sheets ensured all size ranges were equally sampled within each region.
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.
Organization
Alaska Fisheries Science Center
AFSC
afsc.webmaster@noaa.gov
7600 Sand Point Way N.E., Building 4
Seattle
WA
98115
USA
(206) 526-4000
(206) 526-4004
https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
AKFSC Home Page
Online Resource
0700-1700 Pacific Time
3
Data collected at sea is uploaded to an Oracle database and subjected to a thorough QA/QC process.
Organization
Alaska Fisheries Science Center
AFSC
afsc.webmaster@noaa.gov
7600 Sand Point Way N.E., Building 4
Seattle
WA
98115
USA
(206) 526-4000
(206) 526-4004
https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
AKFSC Home Page
Online Resource
0700-1700 Pacific Time
4
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. Prior to 2010, the weight-size relationships were based on limited data (< 500 samples for all species) and estimates from survey data total weights. In 2010 the relationships were revised based on species-specific length and weight data collect during EBS surveys from 2006 to 2010 from > 1,000 measurements made for each species. Length and weight data currently being collected on the survey annually will be used to assess relative changes to the relationship overtime and correlated with
environmental variables. 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.
Organization
Alaska Fisheries Science Center
AFSC
afsc.webmaster@noaa.gov
7600 Sand Point Way N.E., Building 4
Seattle
WA
98115
USA
(206) 526-4000
(206) 526-4004
https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
AKFSC Home Page
Online Resource
0700-1700 Pacific Time
23469
Entity
EBSCRAB
gov.noaa.nmfs.inport:17108
Doug Turnbull
2012-12-05T14:10:39
SysAdmin InPortAdmin
2024-01-15T12:08:04
2018-11-26
Alaska Fisheries Science Center
AFSC
7600 Sand Point Way N.E., Building 4
Seattle
WA
98115
USA
http://www.afsc.noaa.gov
0700-1700 Pacific Time
1001
Public
No
2018-11-26
1 Year
2019-11-26
none
crab
Kingdom
Animalia
Genus
Chionoecetes
Species
bairdi
southern tanner crab
Genus
Chionoecetes
Species
opilio
snow crab
Genus
Paralithodes
Species
camtschaticus
red king crab
Genus
Paralithodes
Species
platypus
blue king crab
Genus
Lithodes
Species
aequispinus
golden king crab
Genus
Chionoecetes
Species
hybrid
hybrid Tanner crab
Genus
Erimacrus
Species
isenbeckii
horsehair crab
EBSCRAB
NA
AFSC
CRAB_ID
Unique number generated by Oracle that identifies each record in the CRAB.EBSCRAB table
AFSC
NA
NA
HAULJOIN
NA
AFSC
NA
NA
CRUISE
6-digit number assigned to each RACE survey cruise; first 4 digits identify cruise year
AFSC
NA
NA
VESSEL
Numeric code assigned to each vessel participating in a RACE cruise (source: RACE ADP codebook)
AFSC
NA
NA
HAUL
Number identifying a specific tow
AFSC
NA
NA
STATION
NA
AFSC
unknown
SPECIES_CODE
5-digit number assigned to a species (source: RACE ADP codebook)
AFSC
NA
NA
SPECIES_KFRC
Numeric code assigned to a species (source: NMFS Kodiak Shellfish Assessment Program)
AFSC
NA
NA
SEX
1-digit numeric code assigned to a particular sex of crab
AFSC
1
male
AFSC
2
female
AFSC
3
unidentifiable
AFSC
4
hermaphrodite
AFSC
LENGTH
Carapace measurement, in millimeters, of king and hair crabs
AFSC
NA
NA
WIDTH
Carapace measurement, in millimeters, of Chionoecetes and Dungeness crabs
AFSC
NA
NA
SHELL_CONDITION
1-digit numeric code describing carapace condition of crab
AFSC
0
pre_molt and molting crab
AFSC
1
soft
AFSC
2
new; firm to hard
AFSC
3
old
AFSC
4
very old
AFSC
5
ancient
AFSC
9
missing data
AFSC
EGG_COLOR
1-digit numeric code describing color of eggs in female crab
AFSC
0
no eggs
AFSC
2
purple
AFSC
3
brown
AFSC
4
orange
AFSC
5
purple-brown
AFSC
6
pink
AFSC
7
cream/yellow
AFSC
9
missing data
AFSC
EGG_CONDITION
1-digit numeric code describing condition of eggs in female crab
AFSC
0
no eggs
AFSC
1
uneyed eggs
AFSC
2
eyed eggs
AFSC
3
dead eggs
AFSC
4
empty egg cases
AFSC
9
missing data
AFSC
CLUTCH_SIZE
1-digit numeric code describing fullness of clutch in female crab
AFSC
0
immature
AFSC
1
mature female with no eggs
AFSC
2
trace to 1/8 full
AFSC
3
1/4 full
AFSC
4
1/2 full
AFSC
5
3/4 full
AFSC
6
full
AFSC
9
missing data
AFSC
WEIGHT
Weight, in grams, of individual crab
AFSC
NA
NA
SPECIAL_SAMPLE
1-digit numeric code indicating presence of certain diseases in crab
AFSC
NA
NA
SPECIAL1
If black mat disease is present, this 1-digit number describes percent of dorsal body surface covered by disease
AFSC
NA
NA
SPECIAL2
If black mat disease is present, this 1-digit number describes percent of ventral body surface covered by disease
AFSC
NA
NA
SPECIAL3
If black mat disease is present, this 1-digit number describes percent of leg surface covered by disease
AFSC
NA
NA
SAMPLING_FACTOR
NA
AFSC
NA
NA
CHELA_HEIGHT
Measurement, in millimeters, of height of right chela of crab
AFSC
NA
NA
GIS_STATION
NA
AFSC
unknown
COMMENTS
Any comments particular to that crab record or haul
AFSC
unknown
RACE Shellfish Assessment Program eastern Bering Sea shelf crab database EBSCRAB
Refer to the pdf document Crab Code Instructions" provided with this dataset for a detailed description of the codes