These data are .csv files of capture data from tagged sea otters in the Santa Barbara Channel Study. Sea otters were captured using highly specialized techniques employed by a team a rebreather divers and were processed by a shore team and veterinary crew at a mobile vet lab. Overall health assessments and morphometric data were collected, and the otters received colored flipper tags (for visual identification in the field) as well as VHF radio transmitter implants (for locating and "re-sighting" individuals) and time-depth recorder instruments (for archival logging of dive records and core body temperature for individual sea otters). Fields include an individual otter identification number, capture date, general location, specific location (lat/long), sex, age class, weight, length, age, date each otter was last seen, dates of re-capture, outcome of each individual otter by the end of the study, and birth date and outcome of each pup born during the study. These data support the followinf publication: Tinker, M.T., Tomoleoni, Joseph, LaRoche, Nicole, Bowen, Lizabeth, Miles, A. Keith, Murray, Mike, Staedler, Michelle, and Randell, Zach, 2017, Southern sea otter range expansion and habitat use in the Santa Barbara Channel, California: U.S. Geological Survey Open-File Report 2017–1001 (OCS Study BOEM 2017-002), 76 p., http://doi.org/10.3133/ofr20171001.

These data are .csv files of tagged sea otter re-sighting locations (henceforth, resights) collected in the field using a combination of VHF radio telemetry and direct observation using high powered (80x) telescopes. Sea otters were tracked by shore or boat-based observers from the date of tagging until the time of radio battery failure, the animal’s death, or the end of the project, whichever comes first. The frequency of re-sighting was opportunistic, depending on logistical factors such as coastal access, but generally ranged from daily to weekly. Location coordinates are reported latitude and longitude as well as X and Y coordinates in the projection/datum California Teale-Albers NAD 1927. The file contains resight data for all tagged sea otters in the Santa Barbara Channel Study, collected over a period of 2.5 years. Fields include individual identification numbers, sex, age class, geographic coordinates, the date and time of the re-sighting location, and associated behavioral state of the individual at the time of re-sighting. These data support the followinf publication: Tinker, M.T., Tomoleoni, Joseph, LaRoche, Nicole, Bowen, Lizabeth, Miles, A. Keith, Murray, Mike, Staedler, Michelle, and Randell, Zach, 2017, Southern sea otter range expansion and habitat use in the Santa Barbara Channel, California: U.S. Geological Survey Open-File Report 2017–1001 (OCS Study BOEM 2017-002), 76 p., http://doi.org/10.3133/ofr20171001.

These data are .csv files of tagged sea otter re-sighting locations (henceforth, resights) collected in the field using a combination of VHF radio telemetry and direct observation using high powered (80x) telescopes. Sea otters were tracked by shore or boat-based observers from the date of tagging until the time of radio battery failure, the animal’s death, or the end of the project, whichever comes first. The frequency of re-sighting was opportunistic, depending on logistical factors such as coastal access, but generally ranged from daily to weekly. Location coordinates are reported latitude and longitude as well as X and Y coordinates in the projection/datum California Teale-Albers NAD 1927. The file contains resight data for all tagged sea otters in the Santa Barbara Channel Study, collected over a period of 2.5 years. Fields include individual identification numbers, sex, age class, geographic coordinates, the date and time of the re-sighting location, and associated behavioral state of the individual at the time of re-sighting. These data support the followinf publication: Tinker, M.T., Tomoleoni, Joseph, LaRoche, Nicole, Bowen, Lizabeth, Miles, A. Keith, Murray, Mike, Staedler, Michelle, and Randell, Zach, 2017, Southern sea otter range expansion and habitat use in the Santa Barbara Channel, California: U.S. Geological Survey Open-File Report 2017–1001 (OCS Study BOEM 2017-002), 76 p., http://doi.org/10.3133/ofr20171001.

These data are .csv files of tagged sea otter re-sighting locations (henceforth, resights) collected in the field using a combination of VHF radio telemetry and direct observation using high powered (80x) telescopes. Sea otters were tracked by shore or boat-based observers from the date of tagging until the time of radio battery failure, the animal’s death, or the end of the project, whichever comes first. The frequency of re-sighting was opportunistic, depending on logistical factors such as coastal access, but generally ranged from daily to weekly. Location coordinates are reported latitude and longitude as well as X and Y coordinates in the projection/datum California Teale-Albers NAD 1927. The file contains resight data for all tagged sea otters in the Santa Barbara Channel Study, collected over a period of 2.5 years. Fields include individual identification numbers, sex, age class, geographic coordinates, the date and time of the re-sighting location, and associated behavioral state of the individual at the time of re-sighting. These data support the followinf publication: Tinker, M.T., Tomoleoni, Joseph, LaRoche, Nicole, Bowen, Lizabeth, Miles, A. Keith, Murray, Mike, Staedler, Michelle, and Randell, Zach, 2017, Southern sea otter range expansion and habitat use in the Santa Barbara Channel, California: U.S. Geological Survey Open-File Report 2017–1001 (OCS Study BOEM 2017-002), 76 p., http://doi.org/10.3133/ofr20171001.

The GIS shapefile "Census summary of southern sea otter 2016" provides a standardized tool for examining spatial patterns in abundance and demographic trends of the southern sea otter (Enhydra lutris nereis), based on data collected during the spring 2016 range-wide census. The USGS range-wide sea otter census has been undertaken twice a year since 1982, once in May and once in October, using consistent methodology involving both ground-based and aerial-based counts. The spring census is considered more accurate than the fall count, and provides the primary basis for gauging population trends by State and Federal management agencies. This Shape file includes a series of summary statistics derived from the raw census data, including sea otter density (otters per square km of habitat), linear density (otters per km of coastline), relative pup abundance (ratio of pups to independent animals) and 5-year population trend (calculated as exponential rate of change). All statistics are calculated and plotted for small sections of habitat in order to illustrate local variation in these statistics across the entire mainland distribution of sea otters in California (as of 2016). Sea otter habitat is considered to extend offshore from the mean low tide line and out to the 60m isobath: this depth range includes over 99% of sea otter feeding dives, based on dive-depth data from radio tagged sea otters (Tinker et al 2006, 2007). Sea otter distribution in California (the mainland range) is considered to comprise this band of potential habitat stretching along the coast of California, and bounded to the north and south by range limits defined as "the points farthest from the range center at which 5 or more otters are counted within a 10km contiguous stretch of coastline (as measured along the 10m bathymetric contour) during the two most recent spring censuses, or at which these same criteria were met in the previous year". The polygon corresponding to the range definition was then sub-divided into onshore/offshore strips roughly 500 meters in width. The boundaries between these strips correspond to ATOS (As-The-Otter-Swims) points, which are arbitrary locations established approximately every 500 meters along a smoothed 5 fathom bathymetric contour (line) offshore of the State of California.

The GIS shapefile "Census summary of southern sea otter 2016" provides a standardized tool for examining spatial patterns in abundance and demographic trends of the southern sea otter (Enhydra lutris nereis), based on data collected during the spring 2016 range-wide census. The USGS range-wide sea otter census has been undertaken twice a year since 1982, once in May and once in October, using consistent methodology involving both ground-based and aerial-based counts. The spring census is considered more accurate than the fall count, and provides the primary basis for gauging population trends by State and Federal management agencies. This Shape file includes a series of summary statistics derived from the raw census data, including sea otter density (otters per square km of habitat), linear density (otters per km of coastline), relative pup abundance (ratio of pups to independent animals) and 5-year population trend (calculated as exponential rate of change). All statistics are calculated and plotted for small sections of habitat in order to illustrate local variation in these statistics across the entire mainland distribution of sea otters in California (as of 2016). Sea otter habitat is considered to extend offshore from the mean low tide line and out to the 60m isobath: this depth range includes over 99% of sea otter feeding dives, based on dive-depth data from radio tagged sea otters (Tinker et al 2006, 2007). Sea otter distribution in California (the mainland range) is considered to comprise this band of potential habitat stretching along the coast of California, and bounded to the north and south by range limits defined as "the points farthest from the range center at which 5 or more otters are counted within a 10km contiguous stretch of coastline (as measured along the 10m bathymetric contour) during the two most recent spring censuses, or at which these same criteria were met in the previous year". The polygon corresponding to the range definition was then sub-divided into onshore/offshore strips roughly 500 meters in width. The boundaries between these strips correspond to ATOS (As-The-Otter-Swims) points, which are arbitrary locations established approximately every 500 meters along a smoothed 5 fathom bathymetric contour (line) offshore of the State of California.

The GIS shapefile "Range extent of southern sea otters 2016" is a simple polyline representing the geographic distribution of the southern sea otter (Enhydra lutris nereis) in mainland California, based on data collected during the spring 2016 range-wide census. The USGS range-wide sea otter census has been undertaken twice a year since 1982, once in May and once in October, using consistent methodology involving both ground-based and aerial-based counts. The spring census is considered more accurate than the fall count, and provides the primary basis for gauging population trends by State and Federal management agencies. Sea otter distribution in California (the mainland range) is considered to comprise a band of potential habitat stretching along the coast of California, and bounded to the north and south by range limits defined as "the points farthest from the range center at which 5 or more otters are counted within a 10km contiguous stretch of coastline (as measured along the 10m bathymetric contour) during the two most recent spring censuses, or at which these same criteria were met in the previous year".

The GIS shapefile "Range extent of southern sea otters 2016" is a simple polyline representing the geographic distribution of the southern sea otter (Enhydra lutris nereis) in mainland California, based on data collected during the spring 2016 range-wide census. The USGS range-wide sea otter census has been undertaken twice a year since 1982, once in May and once in October, using consistent methodology involving both ground-based and aerial-based counts. The spring census is considered more accurate than the fall count, and provides the primary basis for gauging population trends by State and Federal management agencies. Sea otter distribution in California (the mainland range) is considered to comprise a band of potential habitat stretching along the coast of California, and bounded to the north and south by range limits defined as "the points farthest from the range center at which 5 or more otters are counted within a 10km contiguous stretch of coastline (as measured along the 10m bathymetric contour) during the two most recent spring censuses, or at which these same criteria were met in the previous year".

The GIS shapefile "Range extent of southern sea otters 2018" is a simple polyline representing the geographic distribution of the southern sea otter (Enhydra lutris nereis) in mainland California, based on data collected during the spring 2018 range-wide census. The USGS range-wide sea otter census has been undertaken each year since 1982, using consistent methodology involving both ground-based and aerial-based counts. The spring provides the primary basis for gauging population trends by State and Federal management agencies. Sea otter distribution in California (the mainland range) is considered to comprise a band of potential habitat stretching along the coast of California, and bounded to the north and south by range limits defined as "the points farthest from the range center at which 5 or more otters are counted within a 10km contiguous stretch of coastline (as measured along the 10m bathymetric contour) during the two most recent spring censuses, or at which these same criteria were met in the previous year".

The GIS shapefile "Range extent of southern sea otters 2018" is a simple polyline representing the geographic distribution of the southern sea otter (Enhydra lutris nereis) in mainland California, based on data collected during the spring 2018 range-wide census. The USGS range-wide sea otter census has been undertaken each year since 1982, using consistent methodology involving both ground-based and aerial-based counts. The spring provides the primary basis for gauging population trends by State and Federal management agencies. Sea otter distribution in California (the mainland range) is considered to comprise a band of potential habitat stretching along the coast of California, and bounded to the north and south by range limits defined as "the points farthest from the range center at which 5 or more otters are counted within a 10km contiguous stretch of coastline (as measured along the 10m bathymetric contour) during the two most recent spring censuses, or at which these same criteria were met in the previous year".