Data Supporting Walrus Areas of Use in the Chukchi Sea During Sparse Sea Ice Cover

Identification_Information:

Citation:

Citation_Information:

Originator: Jay, Chadwick V. (ORCID: 0000-0002-9559-2189)
Originator: Fischbach, Anthony S. (ORCID: 0000-0002-6555-865X)
Originator: Kochnev, Anatoly A.
Publication_Date: 20121108
Title:

Geospatial_Data_Presentation_Form: raster and vector digital data
Publication_Information:

Publication_Place: Anchorage, Alaska
Publisher: U.S. Geological Survey, Alaska Science Center

Other_Citation_Details:

Suggested Citation: Jay, C.V, Fischbach, A.S., Kochnev, A.A. 2012. Data supporting walrus areas of use in the Chukchi Sea during sparse sea ice cover: U.S. Geological Survey data release, https://doi.org/10.5066/F7X928C3

Online_Linkage: https://doi.org/10.5066/F7X928C3
Larger_Work_Citation:

Citation_Information:

Originator: U.S. Geological Survey, Alaska Science Center
Publication_Date: 2005
Title:

Response of Pacific Walrus Populations to a Rapidly Diminishing Sea Ice Environment

Geospatial_Data_Presentation_Form: website
Series_Information:

Series_Name: Alaska Science Portal
Issue_Identification: 96

Publication_Information:

Publication_Place: Anchorage, Alaska
Publisher: U.S. Geological Survey, Alaska Science Center

Other_Citation_Details:

This is a link to the broader USGS Alaska Science Center research project supported by these data. Users will find a description of the research project and links to associated reports, publications, and data products.

Online_Linkage: https://alaska.usgs.gov/portal/project.php?project_id=96

Description:

Abstract:

The dataset consists of geospatial files depicting the estimated June-to-November distribution of walrus foraging and occupancy during a four year period of sparse sea ice cover above the Chukchi Sea continental shelf (2008-2011). The walrus distribution and utilization estimates are based on location data from satellite-linked radio-tracked walruses in the Chukchi Sea (2008-2011). Compared to previous years this period was marked by earlier and more extensive sea ice retreat (June - September) and delayed sea ice freeze-up (October - November). This allowed walruses to arrive earlier, occupy slightly more northern areas, and stay later in the Chukchi Sea than previously. Data are combined for all four years and structured by month (June [06] - November [11]). Within each month, we estimated walrus utilization distributions by using an unweighted movement based kernel density estimator. The kernel density was then weighted by the amount of time walruses spent foraging during each recorded track segment. We present contours of the kernel density ranging from the 10th to 95th percentile.

Purpose:

These data were prepared to better understand the monthly distribution of walruses in the Chukchi Sea.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20080601
Ending_Date: 20111130

Currentness_Reference: observed

Status:

Progress: Complete
Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Description_of_Geographic_Extent: Chukchi Sea
Bounding_Coordinates:

West_Bounding_Coordinate: -179.85
East_Bounding_Coordinate: -159.68
North_Bounding_Coordinate: 72.10
South_Bounding_Coordinate: 67.48

Keywords:

Theme:

Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:ASC509

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: Biota
Theme_Keyword: Environment

Theme:

Theme_Keyword_Thesaurus: NASA GCMD Earth Science Keyword Thesaurus
Theme_Keyword: Animals/vertebrates
Theme_Keyword: Mammals
Theme_Keyword: Carnivores
Theme_Keyword: Seals/sea lions/walruses
Theme_Keyword: Species/Population interactions
Theme_Keyword: Use/Feeding habitats
Theme_Keyword: Marine habitat

Theme:

Theme_Keyword_Thesaurus: USGS CSA Biocomplexity Thesaurus
Theme_Keyword: Marine ecosystems
Theme_Keyword: Coastal ecosystems
Theme_Keyword: Wildlife food habits

Theme:

Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: Wildlife
Theme_Keyword: Geospatial datasets

Theme:

Theme_Keyword_Thesaurus: None
Theme_Keyword: Animal distribution

Place:

Place_Keyword_Thesaurus: USGS Geographic Names Information System (GNIS)
Place_Keyword: Alaska
Place_Keyword: Chukchi Sea

Taxonomy:

Keywords/Taxon:

Taxonomic_Keyword_Thesaurus: None
Taxonomic_Keywords: Walrus
Taxonomic_Keywords: Pacific Walrus
Taxonomic_Keywords: Odobenus rosmarus divergens

Taxonomic_System:

Classification_System/Authority:

Classification_System_Citation:

Citation_Information:

Originator: ITIS Integrated Taxonomic Information System
Publication_Date: Unknown
Title: ITIS Integrated Taxonomic Information System
Geospatial_Data_Presentation_Form: online database
Publication_Information:

Publication_Place: online
Publisher: ITIS-North America

Other_Citation_Details:

Taxonomic details retrieved December 8, 2022 from the Integrated Taxonomic Information System online database https://www.itis.gov

Online_Linkage: https://doi.org/10.5066/F7KH0KBK

Taxonomic_Procedures: Species were identified by skilled observers in the field.
Taxonomic_Completeness:

Taxonomy is complete for all samples. No vouchers were collected.

Taxonomic_Classification:

Taxon_Rank_Name: Kingdom
Taxon_Rank_Value: Animalia
Taxonomic_Classification:

Taxon_Rank_Name: Subkingdom
Taxon_Rank_Value: Bilateria
Taxonomic_Classification:

Taxon_Rank_Name: Infrakingdom
Taxon_Rank_Value: Deuterostomia
Taxonomic_Classification:

Taxon_Rank_Name: Phylum
Taxon_Rank_Value: Chordata
Taxonomic_Classification:

Taxon_Rank_Name: Subphylum
Taxon_Rank_Value: Vertebrata
Taxonomic_Classification:

Taxon_Rank_Name: Infraphylum
Taxon_Rank_Value: Gnathostomata
Taxonomic_Classification:

Taxon_Rank_Name: Superclass
Taxon_Rank_Value: Tetrapoda
Taxonomic_Classification:

Taxon_Rank_Name: Class
Taxon_Rank_Value: Mammalia
Taxonomic_Classification:

Taxon_Rank_Name: Subclass
Taxon_Rank_Value: Theria
Taxonomic_Classification:

Taxon_Rank_Name: Infraclass
Taxon_Rank_Value: Eutheria
Taxonomic_Classification:

Taxon_Rank_Name: Order
Taxon_Rank_Value: Carnivora
Taxonomic_Classification:

Taxon_Rank_Name: Suborder
Taxon_Rank_Value: Caniformia
Taxonomic_Classification:

Taxon_Rank_Name: Family
Taxon_Rank_Value: Odobenidae
Taxonomic_Classification:

Taxon_Rank_Name: Genus
Taxon_Rank_Value: Odobenus
Taxonomic_Classification:

Taxon_Rank_Name: Species
Taxon_Rank_Value: Odobenus rosmarus
Applicable_Common_Name: Walrus
Applicable_Common_Name: TSN: 180639
Taxonomic_Classification:

Taxon_Rank_Name: Subspecies
Taxon_Rank_Value: Odobenus rosmarus divergens
Applicable_Common_Name: Pacific Walrus
Applicable_Common_Name: TSN: 622045

Access_Constraints: None
Use_Constraints:

It is requested that the authors and the USGS Alaska Science Center be cited for any subsequent publications that reference this dataset.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey, Alaska Science Center

Contact_Address:

Address_Type: Mailing and Physical
Address: 4210 University Drive
City: Anchorage
State_or_Province: Alaska
Postal_Code: 99508
Country: USA

Contact_Voice_Telephone: 907-786-7000
Contact_Electronic_Mail_Address: ascweb@usgs.gov

Cross_Reference:

Citation_Information:

Originator: Jay, C.V.
Originator: Fischbach, A.S.
Originator: Kochnev, A.A.
Publication_Date: 2012
Title:

Walrus Areas of Use in the Chukchi Sea During Sparse Sea Ice Cover

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Marine Ecology Progress Series (MEPS)
Issue_Identification: 468:1-13

Publication_Information:

Publication_Place: online
Publisher: Inter-Research Science Center

Other_Citation_Details:

Jay, C.V., Fischbach, A.S., Kochnev, A.A. 2012. Walrus areas of use in the Chukchi Sea during sparse sea ice cover. Marine Ecology Progress Series 468:1-13 doi:10.3354/meps10057

Online_Linkage: https://doi.org/10.3354/meps10057

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report: All attributes have been checked for accuracy.

Logical_Consistency_Report:

Attribute values fall within expected ranges and data were proofed for the presence of duplication and omission.

Completeness_Report: No data were omitted and there are no missing data.
Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

These monthly distribution polygons have been summarized from tracking location and hourly behavior records collected from numerous walruses tracked by Argos System satellite-linked radio tags. These summarized monthly distributions are subject to sampling variability as the authors infer the distribution of the Pacific walrus population as a whole within the study area and study month from the summarized distribution of sampled walruses. Please see the Discussion section of Jay et al. (2012) which discusses limitations of this sampling and suggests months during which the sampling may have resulted in a biased understanding of the distribution. In particular: "Tagging effort differed between the eastern and western sides of our study area. In U.S. waters, we feel we obtained good spatial coverage of walrus movements and areas of use throughout the Chukchi Sea from June through October (most walruses moved to the southwestern Chukchi Sea by November). In Russian waters, we feel the spatial coverage of walrus movements we obtained was good in June, fair in July, weak in August and September, good in October (except perhaps in the northwestern areas), and good in November. Therefore, the relative concentration of walrus foraging and occupancy within our study area are biased towards the eastern side of our study area, particularly in July to September." (Jay et al 2012)

Lineage:

Methodology:

Methodology_Type: Field
Methodology_Description:

We attached 251 satellite radio-tags (Telonics Inc., Mesa, Arizona) to walruses (Odobenus rosmarus divergens) resting on sea ice and beaches in the northern Bering Strait region and the Chukchi Sea in summer and fall (2008-2011). The tags were similar to the tags described in Fischbach and Jay (2016) and were deployed by using a crossbow or jab stick. We attached the tags on adult walruses (primarily females, n = 222).

Methodology:

Methodology_Type: Lab
Methodology_Description:

We received data and geographic location estimates from the Argos location and data collection system. Argos location estimates were filtered through the Douglas Argos-filter algorithm (Douglas et al 2012), which uses spatial redundancy, movement rates, and angles to select between primary and alternate Argos locations and rejects unreasonable location estimates.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Douglas, D.C.
Originator: Weinzierl, R.
Originator: Davidson, S.C.
Originator: Kays, R.
Originator: Wikelski, M.
Originator: Bohrer, G.
Publication_Date: 2012
Title: Moderating Argos Location Errors in Animal Tracking Data
Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Methods in Ecology and Evolution
Issue_Identification: 3(6):999-1007

Publication_Information:

Publication_Place: online
Publisher: Wiley

Other_Citation_Details:

Douglas, D.C., Weinzierl, R., Davidson, S.C., Kays, R., Wikelski, M., Bohrer, G. 2012. Moderating Argos location errors in animal tracking data. Methods in Ecology and Evolution 3(6):999-1007 doi:10.1111/j.2041-210X.2012.00245.x

Online_Linkage: https://doi.org/10.1111/j.2041-210X.2012.00245.x

Type_of_Source_Media: journal article
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2012

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Douglas et al 2012
Source_Contribution:

Describes the use of the "Douglas Argos Filter" (DAF) for flagging implausible locations.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Benhamou S.
Originator: Cornélis D.
Publication_Date: 2010
Title:

Incorporating Movement Behavior and Barriers to Improve Kernel Home Range Space Use Estimates

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Journal of Wildlife Management
Issue_Identification: 74(6):1353-1360

Publication_Information:

Publication_Place: online
Publisher: Wiley

Other_Citation_Details:

Benhamou S., Cornélis D. 2010. Incorporating movement behavior and barriers to improve kernel home range space use estimates. Journal of Wildlife Management 74(6):1353−1360 doi:10.1111/j.1937-2817.2010.tb01257.x

Online_Linkage: http://doi.org/10.1111/j.1937-2817.2010.tb01257.x

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2010

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Benhamou and Cornelis 2010
Source_Contribution: Describes details of movement-based kernel density estimator.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Jay, C.V.
Originator: Heide-JØrgensen, M.P.
Originator: Fischbach, A.S.
Originator: Jensen, M.V.
Originator: Tessler, D.F.
Originator: Jensen, A.V.
Publication_Date: 2006
Title:

Comparison of Remotely Deployed Satellite Radio Transmitters on Walruses

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Marine Mammal Science
Issue_Identification: 22(1):226-236

Publication_Information:

Publication_Place: online
Publisher: Wiley

Other_Citation_Details:

Jay, C.V., Heide-JØrgensen, M.P., Fischbach, A.S., Jensen, M.V., Tessler, D.F., Jensen, A.V. 2006. Comparison of remotely deployed satellite radio transmitters on walruses. Marine Mammal Science 22(1):226-236 doi:10.1111/j.1748-7692.2006.00018.x

Online_Linkage: http://doi.org/10.1111/j.1748-7692.2006.00018.x

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2006

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Jay et al 2006
Source_Contribution: Describes marking walruses with satellite tags.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Jay, C.V.
Originator: Fischbach, A.S.
Originator: Kochnev, A.A.
Publication_Date: 2012
Title:

Walrus Areas of Use in the Chukchi Sea During Sparse Sea Ice Cover

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Marine Ecology Progress Series (MEPS)
Issue_Identification: 468:1-13

Publication_Information:

Publication_Place: online
Publisher: Inter-Research Science Center

Other_Citation_Details:

Jay, C.V., Fischbach, A.S., Kochnev, A.A. 2012. Walrus areas of use in the Chukchi Sea during sparse sea ice cover. Marine Ecology Progress Series 468:1-13 doi:10.3354/meps10057

Online_Linkage: https://doi.org/10.3354/meps10057

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2012

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Jay et al 2012
Source_Contribution:

Describes details of satellite tracking and utilization distribution models.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Kie, J.G.
Originator: Matthiopoulos, J.
Originator: Fieberg, J.
Originator: Powell, R.A.
Originator: Cagnacci, F.
Originator: Mitchell, M.S.
Originator: Gaillard, J.-M.
Originator: Moorcroft, P.R.
Publication_Date: 2010
Title:

The Home-Range Concept: are Traditional Estimators Still Relevant with Modern Telemetry Technology?

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name:

Philosophical Transactions of the Royal Society B: Biological Sciences

Issue_Identification: 365(1550):2221−2231

Publication_Information:

Publication_Place: online
Publisher: The Royal Society

Other_Citation_Details:

Kie, J.G., Matthiopoulos, J., Fieberg, J., Powell, R.A., Cagnacci, F., Mitchell, M.S., Gaillard J.-M., Moorcroft, P.R. 2010. The home-range concept: Are traditional estimators still relevant with modern telemetry technology? Philosophical Transactions of the Royal Society B: Biological Science 365(1550):2221−2231 doi:10.1098/rstb.2010.0093

Online_Linkage: http://doi.org/10.1098/rstb.2010.0093

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2010

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Kie et al 2010
Source_Contribution: Describes utilization distributions using kernel methods.

Process_Step:

Process_Description:

We estimated utilization distributions (UDs) using kernel methods (Kie et al. 2010). We used a grid cell size of 5 km2 to partially account for spatial errors associated with Argos location estimates while allowing for relatively fine resolution of spatial structure on the scale of our study area. To minimize linear distortion of walrus movements, all data were projected into an azimuthal equidistant projection centered on the study area (70°N, 170° W).

Process_Date: Unknown

Process_Step:

Process_Description:

We used the Benhamou and Cornelis 2010 movement-based kernel density estimator to estimate a UD of walrus foraging and, separately, a UD of walrus occupancy across the Chukchi Sea during each of the study months using the spatial analysis package adehabitatHR written in Program R. To estimate a UD of foraging in a month, we estimated, for each walrus, a UD for each track segment, then summed the UD volume within each grid cell across all track segments with the volume from each track segment multiplied by the proportion of hours spent foraging during the track segment, and then re-scaled each cell volume so that the total volume within the study area summed to 1. In addition to estimating monthly UDs of walrus foraging, we estimated monthly UDs of walrus occupancy by following the above procedure, but without weighting each track segment by number of hours spent foraging. Additional data processing details are available in Jay et al 2012.

Process_Date: Unknown

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:

Raster_Object_Type: Pixel
Row_Count: 3046
Column_Count: 2208

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Azimuthal Equidistant
Azimuthal_Equidistant:

Longitude_of_Central_Meridian: -170
Latitude_of_Projection_Origin: 70
False_Easting: 0
False_Northing: 0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:

Abscissa_Resolution: 5000
Ordinate_Resolution: 5000

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: World Geodetic System of 1984 (WGS84)
Ellipsoid_Name: World Geodetic System of 1984 (WGS84)
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257223563

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: USGS_Walrus_UD_Forage_PNGs
Entity_Type_Definition:

Folder with georeferenced raster files showing estimated Walrus foraging utilization distributions by month. Files are Azimuthal equidistant centered on 170W 70N. Presented as georeferenced Portable Network Graphic (Geo PNG) files. Additionally, a non-georeferenced 'browse image' map (showing all months together) is provided as a separate image file in this data package: "USGS_Walrus_UD_Forage_Jun_Nov_BrowseImage.png".

*NOTE - a legend indicating the color representation for each UD contour is provided as a separate image file in this data package: "USGS_Walrus_UD_Forage_Legend.png".

Filenaming convention: USGS_Walrus_UD_Forage_aed170_70_[MM]; where [MM] = two-digit month

Entity_Type_Definition_Source: Author defined

Detailed_Description:

Entity_Type:

Entity_Type_Label: Walrus_Forage_Jun-Nov_KMZs
Entity_Type_Definition:

Folder with vector polygon files showing estimated Walrus foraging utilization distribution by month, using geographic coordinates (WGS84). Presented as a Keyhole Markup Language Zipped (KMZ) file.

Filenaming convention: WalrusUD[MM]_fromGM_transparent; where [MM] = two-digit month

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: id
Attribute_Definition:

Unique ID for each record. A concatenation of the method, month, contour.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: Unique ID for each record

Attribute:

Attribute_Label: Area_sq_Km
Attribute_Definition:

Area of the Chukchi Sea encompassed by the contour (Method, month, percentile).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 38
Range_Domain_Maximum: 233346
Attribute_Units_of_Measure: Square Kilometers

Attribute:

Attribute_Label: Method
Attribute_Definition:

Whether the contour represents walrus occupancy or foraging distribution

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Foraging
Enumerated_Domain_Value_Definition: Foraging distribution
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Month
Attribute_Definition: Month represented by the contour
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 06
Range_Domain_Maximum: 11
Attribute_Units_of_Measure: Month (MM)

Attribute:

Attribute_Label: Contour
Attribute_Definition:

The percentile of the walrus population estimated to be utilizing the area within contour.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 10
Range_Domain_Maximum: 95
Attribute_Units_of_Measure: Percentile

Detailed_Description:

Entity_Type:

Entity_Type_Label: USGS_Walrus_UD_Occupancy_KMZs
Entity_Type_Definition:

Folder with vector polygon files showing estimated Walrus occupancy distribution by month, using geographic coordinates (WGS84). Presented as a Keyhole Markup Language Zipped (KMZ) file.

File naming convention: USGS_Walrus_UD_Occupancy_[MM]; where [MM] = two-digit month

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: id
Attribute_Definition:

Unique ID for each record. A concatenation of the method, month, contour.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: Unique ID for each record

Attribute:

Attribute_Label: Area_sq_Km
Attribute_Definition:

Area of the Chukchi Sea encompassed by the contour (Method, month, percentile).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 422
Range_Domain_Maximum: 23614
Attribute_Units_of_Measure: Square Kilometers

Attribute:

Attribute_Label: Method
Attribute_Definition:

Whether the contour represents walrus occupancy or foraging distribution

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Occupancy
Enumerated_Domain_Value_Definition: Occupancy distribution
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Month
Attribute_Definition: Month represented by the contour
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 06
Range_Domain_Maximum: 11
Attribute_Units_of_Measure: Month (MM)

Attribute:

Attribute_Label: Contour
Attribute_Definition:

The percentile of the walrus population estimated to be utilizing the area within contour.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 10
Range_Domain_Maximum: 95
Attribute_Units_of_Measure: Percentile

Detailed_Description:

Entity_Type:

Entity_Type_Label: USGS_Walrus_UD_Occupancy_aed170_70_shp
Entity_Type_Definition:

Vector polygon file showing utilization distribution contours for walruses in the Chukchi Sea June-November (2008-2011). Geospatial data presented as an ESRI Shapefile (SHP).

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: id
Attribute_Definition:

Unique ID for each record. A concatenation of the method, month, contour.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: Unique ID for each record

Attribute:

Attribute_Label: Area_sq_Km
Attribute_Definition:

Area of the Chukchi Sea encompassed by the contour (Method, month, percentile).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 38
Range_Domain_Maximum: 23614
Attribute_Units_of_Measure: Square Kilometers

Attribute:

Attribute_Label: Method
Attribute_Definition:

Whether the contour represents walrus occupancy or foraging distribution

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Occupancy
Enumerated_Domain_Value_Definition: Occupancy distribution
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Foraging
Enumerated_Domain_Value_Definition: Foraging distribution
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Month
Attribute_Definition: Month represented by the contour
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 06
Range_Domain_Maximum: 11
Attribute_Units_of_Measure: Month (MM)

Attribute:

Attribute_Label: Contour
Attribute_Definition:

The percentile of the walrus population estimated to be utilizing the area within contour.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 10
Range_Domain_Maximum: 95
Attribute_Units_of_Measure: Percentile

Detailed_Description:

Entity_Type:

Entity_Type_Label: USGS_Walrus_UD_Occupancy_geo_shp
Entity_Type_Definition:

Vector polygon file showing occupancy distribution contours for walruses in the Chukchi Sea June-November (2008-2011). Geospatial data presented as an ESRI Shapefile (SHP).

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: id
Attribute_Definition:

Unique ID for each record. A concatenation of the method, month, contour.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: Unique ID for each record

Attribute:

Attribute_Label: Area_sq_Km
Attribute_Definition:

Area of the Chukchi Sea encompassed by the contour (Method, month, percentile).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 422
Range_Domain_Maximum: 23614
Attribute_Units_of_Measure: Square Kilometers

Attribute:

Attribute_Label: Method
Attribute_Definition:

Whether the contour represents walrus occupancy or foraging distribution

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Occupancy
Enumerated_Domain_Value_Definition: Occupancy distribution
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Month
Attribute_Definition: Month represented by the contour
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 06
Range_Domain_Maximum: 11
Attribute_Units_of_Measure: Month (MM)

Attribute:

Attribute_Label: Contour
Attribute_Definition:

The percentile of the walrus population estimated to be utilizing the area within contour.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 50
Range_Domain_Maximum: 95
Attribute_Units_of_Measure: Percentile

Data Supporting Walrus Areas of Use in the Chukchi Sea During Sparse Sea Ice Cover

Metadata: