Sea Otter Aerial Survey Data from Western Prince William Sound, Alaska, 2017

Identification_Information:

Citation:

Citation_Information:

Originator: Esslinger, G.G. (ORCID:0000-0002-3459-0083)
Originator: Monson, D.H. (ORCID:0000-0002-4593-5673)
Originator: Robinson, B.H. (ORCID:0000-0001-8588-7162)
Publication_Date: 20211201
Title:

Geospatial_Data_Presentation_Form: tabular digital data
Publication_Information:

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

Other_Citation_Details:

Suggested Citation: Esslinger, G.G., Monson, D.H., and Robinson, B.H., 2021, Sea otter aerial survey data from Western Prince William Sound, Alaska, 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P9KNKOG1

Online_Linkage: https://doi.org/10.5066/P9KNKOG1
Larger_Work_Citation:

Citation_Information:

Originator: U.S. Geological Survey, Alaska Science Center
Publication_Date: 2005
Title: Nearshore Marine Ecosystem Research Program
Geospatial_Data_Presentation_Form: website
Series_Information:

Series_Name: Alaska Science Portal
Issue_Identification: 99

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=99

Description:

Abstract:

This dataset consists of three tables related to abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in western Prince William Sound, Alaska, based on data collected during a series of population-wide aerial surveys in June 2017. The dataset consists of: (1) sea otter counts along strip transects, (2) sea otter counts in Intensive Search Unit (ISU) within the transects, and (3) Transect coordinates.

Purpose:

These data were collected as part of Gulf Watch Alaska (https://gulfwatchalaska.org) to assess changes in the abundance and distribution of sea otters in the waters throughout western Prince William Sound, Alaska in 2017.

Supplemental_Information:

Sea otters are a keystone predator, well known for structuring the nearshore marine ecosystem through their consumption of invertebrate prey. To estimate sea otter abundance, the U.S. Geological Survey has designed and conducted multiple aerial surveys in Alaska using a method that adjusts for detection bias. The surveys provide data and a population estimate that federal and state management agencies use for decision making and planning additional research.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20170525
Ending_Date: 20170530

Currentness_Reference: observed

Status:

Progress: Complete
Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Description_of_Geographic_Extent: Nearshore waters in Prince William Sound, Alaska
Bounding_Coordinates:

West_Bounding_Coordinate: -148.83
East_Bounding_Coordinate: -145.50
North_Bounding_Coordinate: 61.50
South_Bounding_Coordinate: 59.67

Keywords:

Theme:

Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:ASC417

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: Otters

Theme:

Theme_Keyword_Thesaurus: USGS CSA Biocomplexity Thesaurus
Theme_Keyword: Aerial surveys
Theme_Keyword: Population density
Theme_Keyword: Abundance (organisms)
Theme_Keyword: Marine mammals
Theme_Keyword: Spatial distribution

Theme:

Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: Wildlife
Theme_Keyword: Ecology
Theme_Keyword: Population dynamics
Theme_Keyword: Ecosystem monitoring

Theme:

Theme_Keyword_Thesaurus: None
Theme_Keyword: Sea otters
Theme_Keyword: Enhydra lutris kenyoni
Theme_Keyword: Northern sea otters

Place:

Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)
Place_Keyword: Alaska
Place_Keyword: Prince William Sound

Taxonomy:

Keywords/Taxon:

Taxonomic_Keyword_Thesaurus: None
Taxonomic_Keywords: Mammals
Taxonomic_Keywords: Carnivore

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 October 13, 2022, from the Integrated Taxonomic Information System online database https://www.itis.gov

Online_Linkage: https://www.itis.gov

Taxonomic_Procedures: Species were identified by experts in the field
Taxonomic_Completeness:

Taxonomy is complete for all samples. No voucher specimens were collected.

Taxonomic_Classification:

Taxon_Rank_Name: Kingdom
Taxon_Rank_Value: Animalia
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: 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: Mustelidae
Taxonomic_Classification:

Taxon_Rank_Name: Subfamily
Taxon_Rank_Value: Lutrinae
Taxonomic_Classification:

Taxon_Rank_Name: Genus
Taxon_Rank_Value: Enhydra
Taxonomic_Classification:

Taxon_Rank_Name: Species
Taxon_Rank_Value: Enhydra lutris
Applicable_Common_Name: Sea otter
Applicable_Common_Name: TSN: 180547
Taxonomic_Classification:

Taxon_Rank_Name: Subspecies
Taxon_Rank_Value: Enhydra lutris kenyoni
Applicable_Common_Name: Northern sea otter
Applicable_Common_Name: TSN: 622038

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

Data_Set_Credit:

Sea otter group locations from the 2017 aerial surveys were mapped during the survey by Dan Monson and later digitized by Brian Robinson. This material is based upon work funded by the Exxon Valdez Oil Spill Trustee Council under Project/Program No. 17120114-H. Any opinions, findings, conclusions, or recommendations expressed herein are those of the author(s) and do not necessarily reflect the views or positions of the Trustee Council.

Cross_Reference:

Citation_Information:

Originator: Esslinger, G.G.
Originator: Robinson, B.H.
Originator: Monson, D.H.
Originator: Taylor, R.L.
Originator: Esler, D.
Originator: Weitzman, B.P
Originator: Garlich-Miller, J.
Publication_Date: 2021
Title:

Abundance and distribution of sea otters (Enhydra lutris) in the Southcentral Alaska stock, 2014, 2017 and 2019

Geospatial_Data_Presentation_Form: document
Series_Information:

Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: 2021-1122

Publication_Information:

Publication_Place: online
Publisher: U.S. Geological Survey

Other_Citation_Details:

Esslinger, G.G, Robinson, B.H., Monson, D.H., Taylor, R.L., Esler, D., Weitzman, B.P., Garlich-Miller, J. 2021. Abundance and distribution of sea otters (Enhydra lutris) in the Southcentral Alaska stock, 2014, 2017 and 2019: U.S. Geological Survey Open-File Report 2021-1122, https://doi.org/10.3133/ofr20211122

Online_Linkage: https://doi.org/10.3133/ofr20211122

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Prior to conducting an aerial survey, each observer underwent a training program that involved comparing aerial counts with ground-based counts and was able to consistently detect at least 90 percent of the sea otters within Intensive Search Units (ISU). Adult sea otters were distinguished from pups when possible and are identified as separate fields in the data. However, small pups may not have been detected and large pups were sometimes indistinguishable from adults. Therefore, pup counts should be regarded as minimum counts. Groups greater than 20 sea otters typically contain active individuals which make it more challenging to obtain accurate counts so photographs are occasionally taken and used to check these counts. Sea otters hauled out on land are typically more difficult to sight but were counted when observed.

During the aerial survey, sea otter locations were mapped on paper maps and later digitized into ArcMap (ESRI). Mapped otter locations are approximate and, especially where sea otters were observed in offshore waters devoid of landmarks, may be off by several hundreds of meters.

We carried out a standard quality assurance quality control (QAQC) procedure for this data. Entries were checked against field data sheets and data standards for accuracy, missing values, outliers, and inconsistencies. When applicable, data were checked against validated ranges.

Logical_Consistency_Report:

Attribute values fall within expected ranges. Null values are represented with "."

Completeness_Report:

This survey was designed to cover all habitat in western Prince William Sound, Alaska where sea otters were known to occur in 2017. All planned survey transects are included in the file "seaOtter_aerialSurveyTransectCoords_westPWS_esslinger_2017.csv" (included with this data package). However, transects or portions of transects may not have been surveyed if the survey crew encountered: (1) hazardous conditions such as downdrafts, (2) land due to low tide, or (3) sensitive areas such as sea lion rookeries. Transects that were not surveyed are not included in the file "seaOtter_aerialSurveyTransectCounts_westPWS_esslinger_2017.csv"

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Transect coordinate accuracy was not tested quantitatively. Many high density transects intersect with the shoreline on at least one end and the vast majority of these planned intersection points seemed to align well with observed locations during the surveys. However, planned shoreline intersection points may not match ground conditions due to factors such as tidal state (especially on gradually sloping beaches), navigation error, and inaccuracies in the shoreline maps used to design the surveys, mostly resulting from changes in the shoreline from ongoing natural processes such as erosion, sedimentation, or isostatic rebound. Mapped otter locations are approximate and, especially where sea otters were observed in offshore waters devoid of landmarks, may be off by several hundreds of meters.

Lineage:

Methodology:

Methodology_Type: Field
Methodology_Description:

Sea otter habitat was divided into two strata, high density and low density, based on distance from shore and water depth. The high density stratum extended from shore to 400 m seaward or to the 40 m depth contour, whichever was greater. The low density stratum extended from the high density line to a line 2 km offshore or to the 100 m depth contour, whichever was greater. Bays and inlets less than 6 km wide were sampled entirely, regardless of depth. Survey effort was allocated proportional to expected otter abundance in the respective strata by adjusting the systematic spacing of transects within each stratum.

For each aerial survey, the pilot flew an airplane at an airspeed of 29 meters per second and an altitude of 91 meters over pre-determined transects while an observer searched on one side of the plane and recorded sea otter group counts and locations. All sea otter groups observed within 400 meters of each transect were recorded. A group of sea otters was defined as 1 or more sea otters spaced less than 3 otter lengths apart. Adult sea otters were distinguished from pups when possible and identified as separate fields in the data. When large groups of sea otters (≥20) were sighted on transect, they were circled until a complete count was made. Sea otters sighted beyond the confines of designated transect swaths were also counted and mapped, time permitting.

We used Intensive Search Units (ISU) to estimate the number of sea otters in small groups (<20) not detected along transect swaths (e.g., due to diving behavior or the presence of kelp canopy). ISUs are 400 meter diameter circles, along the transects, that were searched intensively by periodically flying 5 concentric circles around an initiating group. These ISUs were distributed throughout the survey area in an attempt to accurately represent the full range of observation conditions encountered during the survey. See Esslinger et al. (2021) for additional details of field sampling.

Source_Information:

Source_Citation:

Citation_Information:

Abundance and distribution of sea otters (Enhydra lutris) in the Southcentral Alaska stock, 2014, 2017 and 2019

Geospatial_Data_Presentation_Form: document
Series_Information:

Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: 2021-1122

Publication_Information:

Publication_Place: online
Publisher: U.S. Geological Survey

Other_Citation_Details:

Esslinger, G.G, Robinson, B.H., Monson, D.H., Taylor, R.L., Esler, D., Weitzman, B.P., Garlich-Miller, J. in prep. Abundance and distribution of sea otters (Enhydra lutris) in the Southcentral Alaska stock, 2014, 2017 and 2019: U.S. Geological Survey Open-File Report 2021-1122, https://doi.org/10.3133/ofr20211122

Online_Linkage: https://doi.org/10.3133/ofr20211122

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2021

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Esslinger et al 2021
Source_Contribution: Provides detailed survey methods.

Process_Step:

Process_Description:

Aerial survey observational data were collected by experienced field observers. Field data were recorded on paper field data sheets for electronic entry at a later time.

Process_Date: Unknown

Process_Step:

Process_Description:

The sea otter sightings recorded on paper maps were digitized as points in ArcMap (ESRI) using the "Create Features" pane. Each point indicates the location of a group of one or more sea otters relative to shoreline features, nearby transects, and other sightings. After each point was digitized, the following information was entered into the attribute table: transect number, group number, number of adults, number of pups, ISU number, and date. Sea otter group coordinates were obtained using the "Add XY Coordinates" tool in ArcToolbox (ESRI).

Process_Date: Unknown

Process_Step:

Process_Description:

Quality Assurance/Quality Control (QAQC): Field data sheets QAQC: the aerial observer and then a data manager review the data sheets for missing, illegible, or confusing entries and correct any issues.

Spreadsheet QAQC: tabular sea otter counts are checked against maps showing sea otter group counts and locations, and also checked row by row/cell by cell for accuracy and completeness. Basic descriptive statistics were run on the count data to look for outliers or values inconsistent with the protocol. If outliers or inconsistent values were found, corrections were applied to the data. The descriptive statistics are not part of the dataset, but are used for QAQC. Digitized sea otter sightings were checked by ensuring values entered in the point attribute table matched values recorded by the aerial observer on paper maps, transect count data sheets, and ISU count data sheets.

Process_Date: Unknown

Spatial_Data_Organization_Information:

Indirect_Spatial_Reference:

Transect start and end coordinates are unique for each Survey_Unit, Year, and Replicate combination in the strip transect count data. Sea otter group coordinates are included for each group in the strip transect count data.

Direct_Spatial_Reference_Method: Point

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Geographic:

Latitude_Resolution: 0.0001
Longitude_Resolution: 0.0001
Geographic_Coordinate_Units: Decimal degrees

Geodetic_Model:

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

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: seaOtter_aerialSurveyTransectCounts_westPWS_esslinger_2017.csv
Entity_Type_Definition:

This is spreadsheet data saved as a comma delimited file. Each record (row) represents one group of observed sea otters along a transect. In the case of no otters observed, each row represents one transect.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: SURVEY_UNIT
Attribute_Definition: Up to four character code for the area covered by the survey.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: WPWS
Enumerated_Domain_Value_Definition: The WPWS unit comprises Western Prince William Sound.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: YEAR
Attribute_Definition:

Year of survey; this attribute is preferable to the "date" field for sorting transects within a year.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 2017
Enumerated_Domain_Value_Definition: Survey conducted in 2017.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: DATE
Attribute_Definition:

Date sea otter group was observed, year month day (YYYYMMDD). A "." indicates the date was not recorded by the observer because the record is from an off transect sighting.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 20170525
Range_Domain_Maximum: 20170530
Attribute_Units_of_Measure: Date (YYYYMMDD)

Attribute:

Attribute_Label: OBSERVER
Attribute_Definition:

First initial and first seven letters of last name of aerial observer.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: DMONSON
Enumerated_Domain_Value_Definition: Daniel H Monson
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: REPLICATE
Attribute_Definition:

Replicate number; used to designate the order surveys were flown when more than one survey was flown in a given year.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1
Range_Domain_Maximum: 2

Attribute:

Attribute_Label: STRATUM
Attribute_Definition:

Designates which stratum each transect falls within, high density (H) or low density (L). Sea otter groups sighted off-transect have a "." in this column.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: H
Enumerated_Domain_Value_Definition: High density
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: L
Enumerated_Domain_Value_Definition: Low density
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: .
Enumerated_Domain_Value_Definition:

Sea otter sighting was not on a transect, so no stratum is designated.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: TRANSECT
Attribute_Definition:

Sequential integer number assigned to each transect within a survey when survey is designed. Transect number; designates which transect the sea otter group was observed on, if any. Sea otter groups sighted off-transect have a "0" in this column.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 241

Attribute:

Attribute_Label: GROUP
Attribute_Definition:

Sequential integer number assigned to each group of sea otters along a transect. Group number; used to designate the order sea otter groups were sighted on a given transect. "0" is assigned for otters observed off transect or when no otters are observed along a transect.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 18

Attribute:

Attribute_Label: ADULTS
Attribute_Definition: Number of adult sea otters observed in a group.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 45

Attribute:

Attribute_Label: PUPS
Attribute_Definition: Number of sea otter pups observed in a group.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 5

Attribute:

Attribute_Label: ISU
Attribute_Definition:

Intensive Search Unit; indicates an ISU number if a group of sea otters occurred within an ISU. A "0" in this field indicates no ISUs were flown on that transect. An ISU is a 400m diameter circle, located within the transect strip, where the survey plane flew 5 concentric circles to search for sea otters that were not sighted (for example, because they were diving or camouflaged by kelp). These data were later used to estimate the proportion of sea otters not detected on transects and adjust the overall abundance estimate for each survey accordingly. Sea otter groups sighted during the strip count portion of the ISU are indicated with an ISU number in the file "seaOtter_aerialSurveyTransectCounts_westPWS_esslinger_2017.csv" and also entered into the file "seaOtter_aerialSurveyISUCounts_westPWS_esslinger_2017" (both files included in this data package), linked by the Survey Unit, Year, Replicate, and ISU number.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 31

Attribute:

Attribute_Label: CC
Attribute_Definition:

Complete Count; designates whether a group of sea otters was circled until it was completely counted.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 0
Enumerated_Domain_Value_Definition: No
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 1
Enumerated_Domain_Value_Definition: Yes
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: GROUP_X
Attribute_Definition:

Sea otter group longitude in decimal degrees, WGS84. "." has been entered when there were no otters observed.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -148.3690
Range_Domain_Maximum: -147.1770
Attribute_Units_of_Measure: Decimal degrees (WGS84)

Attribute:

Attribute_Label: GROUP_Y
Attribute_Definition:

Sea otter group latitude in decimal degrees, WGS84. "." has been entered when there were no otters observed.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 59.7982
Range_Domain_Maximum: 60.7358
Attribute_Units_of_Measure: Decimal degrees (WGS84)

Detailed_Description:

Entity_Type:

Entity_Type_Label: seaOtter_aerialSurveyISUCounts_westPWS_esslinger_2017.csv
Entity_Type_Definition:

This is spreadsheet data saved as a comma delimited file. Each record (row) represents one ISU conducted along a transect.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: SURVEY_UNIT
Attribute_Definition: Up to four character code for the area covered by the survey.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: WPWS
Enumerated_Domain_Value_Definition: The WPWS unit comprises Western Prince William Sound, Alaska.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: YEAR
Attribute_Definition:

Year of survey; this attribute is preferable to the "date" field for sorting transects within a year.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 2017
Enumerated_Domain_Value_Definition: Survey conducted in 2017.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: DATE
Attribute_Definition:

Date sea otter group was observed, year month day (YYYYMMDD). A "." indicates the date was not recorded by the observer because the record is from an off transect sighting.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 20170525
Range_Domain_Maximum: 20170530
Attribute_Units_of_Measure: Date (YYYYMMDD)

Attribute:

Attribute_Label: OBSERVER
Attribute_Definition:

First initial and first seven letters of last name of aerial observer.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: DMONSON
Enumerated_Domain_Value_Definition: Daniel H Monson
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: REPLICATE
Attribute_Definition:

Replicate number; used to designate the order surveys were flown when more than one survey was flown in a given year.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1
Range_Domain_Maximum: 2

Attribute:

Attribute_Label: STRATUM
Attribute_Definition:

Designates which stratum each transect falls within, high density (H) or low density (L). Sea otter groups sighted off-transect have a "." in this column.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: H
Enumerated_Domain_Value_Definition: High density
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: L
Enumerated_Domain_Value_Definition: Low density
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: ISU
Attribute_Definition:

Intensive Search Unit; indicates the number of a particular ISU. Sequential integer number assigned to each ISU within a survey. An ISU is a 400m diameter circle, located within the transect strip, where the survey plane flew 5 concentric circles to search for sea otters that were not sighted (for example, because they were diving or camouflaged by kelp). These data were later used to estimate the proportion of sea otters not detected on transects and adjust the overall abundance estimate for each survey accordingly. Sea otter groups sighted during the strip count portion of the ISU are indicated with an ISU number in the "ISU counts" data and also entered into the "Strip transect counts" data, linked by the Survey Unit, Year, Replicate, and ISU number.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1
Range_Domain_Maximum: 31

Attribute:

Attribute_Label: TRANSECT
Attribute_Definition:

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 4
Range_Domain_Maximum: 236

Attribute:

Attribute_Label: GROUP
Attribute_Definition:

Group number, sequential integer number used to designate the order sea otter groups were sighted in a given ISU. A group was defined as 1 or more sea otters spaced less than 3 otter lengths apart.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1
Range_Domain_Maximum: 17

Attribute:

Attribute_Label: STRIP_ADULTS
Attribute_Definition:

Number of adult sea otters observed in a group while flying the strip count portion of an ISU. When the observer asked the pilot to initiate an ISU, the plane temporarily departed the transect flight path to circle the initiating sea otter group 5 times. Any adult sea otters sighted prior to the first quarter turn of the first circle are included in the "Strip_Adults" count.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 4

Attribute:

Attribute_Label: STRIP_PUPS
Attribute_Definition:

Number of sea otter pups observed in a group while flying the strip count portion of an ISU. When the observer asked the pilot to initiate an ISU, the plane temporarily departed the transect flight path to circle the initiating sea otter group 5 times. Any sea otter pups sighted prior to the first quarter turn of the first circle are included in the "Strip_Pups" count.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 1

Attribute:

Attribute_Label: CIRCLE_ADULTS
Attribute_Definition:

Number of adult sea otters observed in a group while flying the circle count portion of an ISU. When the observer asked the pilot to initiate an ISU, the plane temporarily departed the transect flight path to circle the initiating sea otter group 5 times. Any adult sea otters sighted after the first quarter turn of the first circle are included in the "Circle_Adults" count.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1
Range_Domain_Maximum: 8

Attribute:

Attribute_Label: CIRCLE_PUPS
Attribute_Definition:

Number of sea otter pups observed in a group while flying the circle count portion of an ISU. When the observer asked the pilot to initiate an ISU, the plane temporarily departed the transect flight path to circle the initiating sea otter group 5 times. Any sea otter pups sighted after the first quarter turn of the first circle are included in the "Circle_Pups" count.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0
Range_Domain_Maximum: 1

Attribute:

Attribute_Label: BEHAVIOR
Attribute_Definition:

Behavior is defined as "whatever the otter was doing before the plane arrived" and recorded for each group as either diving (D), non-diving (N), or hauled-out (H). "." indicates the behavior was not recorded by the observer. Diving otters include any individuals that swim below the surface and out of view, whether traveling or foraging. If any individual(s) in a group are diving, the whole group is classified as diving. Non-diving otters are animals seen resting, interacting, swimming (but not diving), or hauled-out on land or ice.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: D
Enumerated_Domain_Value_Definition: Diving, out of view
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: N
Enumerated_Domain_Value_Definition: Not Diving
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: H
Enumerated_Domain_Value_Definition: Hauled-out
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: .
Enumerated_Domain_Value_Definition: Behavior not recorded.
Enumerated_Domain_Value_Definition_Source: Author defined

Detailed_Description:

Entity_Type:

Entity_Type_Label: seaOtter_aerialSurveyTransectCoords_westPWS_esslinger_2017.csv
Entity_Type_Definition:

This is spreadsheet data saved as a comma delimited file. Each record (row) represents one transect endpoint, describing a pool of possible survey transects. Not all transects in this transect coordinate file were surveyed. Transects listed in the strip transect counts file were surveyed.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: SURVEY_UNIT
Attribute_Definition: Up to four character code for the area covered by the survey.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: WPWS
Enumerated_Domain_Value_Definition: The WPWS unit comprises Western Prince William Sound, Alaska.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: YEAR
Attribute_Definition:

Year of survey; this attribute is preferable to the "date" field for sorting transects within a year.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 2017
Enumerated_Domain_Value_Definition: Survey conducted in 2017.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: REPLICATE
Attribute_Definition:

Replicate number; used to designate the order surveys were flown when more than one survey was flown in a given year.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1
Range_Domain_Maximum: 2

Attribute:

Attribute_Label: STRATUM
Attribute_Definition:

Designates which stratum each transect falls within, high density (H) or low density (L). Sea otter groups sighted off-transect have a "." in this column.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: H
Enumerated_Domain_Value_Definition: High density
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: L
Enumerated_Domain_Value_Definition: Low density
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: TRANSECT
Attribute_Definition:

Sequential integer number assigned to each transect within a survey when survey is designed along with a letter indicating which end (E = east, W = west). For example, transect 1 in the otter data spreadsheets is designated here by endpoints 001E and 001W. Note that each stratum within each replicate will have their own 001E and 001W.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 001
Range_Domain_Maximum: 241

Attribute:

Attribute_Label: X_COORDINATE
Attribute_Definition: Sea otter group longitude in decimal degrees, WGS84.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -148.7145
Range_Domain_Maximum: -147.1025
Attribute_Units_of_Measure: Decimal degrees (WGS84)

Attribute:

Attribute_Label: Y_COORDINATE
Attribute_Definition: Sea otter group latitude in decimal degrees, WGS84.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 59.7869
Range_Domain_Maximum: 60.7494
Attribute_Units_of_Measure: Decimal degrees (WGS84)

Overview_Description:

Entity_and_Attribute_Overview:

The information contained in these datasets includes strip transect counts, ISU counts, and transect coordinates from sea otter aerial surveys conducted in Western Prince William Sound, Alaska.

Entity_and_Attribute_Detail_Citation: Author defined

Sea Otter Aerial Survey Data from Western Prince William Sound, Alaska, 2017

Metadata: