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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...
Categories: Data;
Types: Citation;
Tags: California,
Santa Barbara Channel Islands,
Santa Barbara County,
Southern sea otter,
movement patterns,
The data consist of levels of organic pollutants found in the blue mussels (Mytelus trossulus) samples from 44 sites along the Aleutian archipelago and in Cross Sound in southeast Alaska. For each site, the percent lipid, percent water and the sum of the target organic compounds are reported. The compounds are PCBs (polychlorinated biphenyls), DDTs (dichlorodiphenyltrichloroethanes), HCHs (hexachlorocyclohexanes), chlordane, and HCB (hexachlorocyclobenzene).
The data consist of levels of organic pollutants found in the blood of sea otters captured from five areas in the western aleutian Islands and in Cross Sound in southeast Alaska. For each location, the sample size, and the median and range of values for each compound is provided. The compounds are PCBs (polychlorinated biphenyls), DDTs (dichlorodiphenyltrichloroethanes), HCHs (hexachlorocyclohexanes), chlordane, HCB (hexachlorocyclobenzene), and dieldrin.
Categories: Data;
Tags: Southeast Alaska,
Western Aleutian Islands,
biota,
health,
organic pollutants,
The current study was designed to provide critical information for resource managers (specifically the Bureau of Ocean Energy Management, henceforth BOEM, and the U.S. Fish and Wildlife Service, henceforth USFWS) about the spatial ecology, population status, and potential population threats to sea otters in Santa Barbara Channel, with particular reference to exposure to manmade structures and sources of oil and natural gas. Our four primary research objectives were: 1. Determine the extent of movements and spatial use patterns by sea otters along the southern California coast 2. Identify important sea otter resting and foraging areas adjacent to manmade structures 3. Assess sea otter distribution, behavior and...
The southern sea otter (Enhydra lutris nereis), also known as California sea otter, was listed as threatened in 1977 under the Endangered Species Act. Since 1985, stranded otters from throughout their California coastal range have been collected and analyzed to inform resource management on recovery and conservation of the species. This data set is a complete 34 year compilation. Future annual stranding recovery information will be published when available. Stranded sea otters were collected by members of the sea otter stranding network (USGS, California Department of Fish and Wildlife (CDFW), Monterey Bay Aquarium (MBA), and the Marine Mammal Center (TMMC)) during routine beach walks and (more often) following...
Categories: Data Release - Revised;
Tags: California,
Marine Nearshore,
Stranded southern sea otters,
USGS Science Data Catalog (SDC),
ecology,
The 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 based observers from the date of tagging until the time of radio battery failure or the animal’s death, 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 as X and Y coordinates in the projection/datum California Teale-Albers NAD 1927. Each file contains resight data for one individual sea otter collected over a period...
Categories: Data;
Types: ArcGIS REST Map Service,
ArcGIS Service Definition,
Citation,
Downloadable,
Map Service;
Tags: California,
Half Moon Bay,
Santa Barbara,
Santa Barbara Channel Islands,
Southern sea otter,
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...
Categories: Data;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
Central California Coast,
Coast,
Southern California Coast,
aerial counts,
The GIS shapefile "Census summary of southern sea otter 2018" 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 2018 range-wide census. The USGS spring 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 census 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...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
Central California Coastal,
Coast,
Southern California Coastal,
aerial counts,
The data table consists of a compilation of sea otter survey results from Bering Island, Russia and select Western Aleutian Islands conducted between 1959 and 2015. The counts were reduced to sea otters per kilometer of coastline for temporal comparability. A correction factor of 3.6 was applied to aerial survey totals to yield results comparable to skiff based surveys. The data table provides the island, year, mode (aerial, skiff, or ground), and shore length covered in each survey. Counts of independent otters and pups are provided if available. Total otters counted or calculated with the correction factor and the calculated linear density are also provided.
Categories: Data;
Tags: Adak Island, Alaska,
Aleutian Islands,
Amchitka Island, Alaska,
Attu Island, Alaska,
Bering Island, Russia,
The spring 2016 mainland sea otter count began on 1 May and was completed on 11 May. Overall viewing conditions this year were very good, being more favorable than those during the 2015 spring census (3.1 vs. 2.6, where 0=poor, 1=fair, 2=good, 3=very good, and 4=excellent) and contributed to the relatively short duration of the count. The surface canopies of kelp (Macrocystis sp.) were considered by most participants to be below normal for this time of year in the northern half of the range and about normal in the southern half. Sea otters along the mainland were surveyed (using a combination of ground-based and aerial-based surveys) from Pillar Point in San Mateo County in the north, to Rincon Point in the south...
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...
Categories: Data;
Types: Citation;
Tags: California,
Santa Barbara Channel Islands,
Santa Barbara County,
Southern sea otter,
movement patterns,
The GIS shapefile "Extra limit counts of southern sea otters 2018" is a point layer representing the locations of sea otter sightings that fall outside the officially recognized range of the southern sea otter (Enhydra lutris nereis) in mainland California. These data were 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 census 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...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
Central California Coastal,
Southern California Coastal,
aerial counts,
biota,
The GIS shapfile "Range extent of southern sea otter 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...
Categories: Data;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
Central California Coast,
Coast,
Southern California Coast,
aerial counts,
The GIS layer "Census_sum_15" 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 2015 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...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
Central California Coast,
Coast,
Southern California Coast,
aerial counts,
Sea otters are well-known tool users, employing objects such as rocks or shells to break open invertebrate prey. We used a series of generalized linear mixed effect models (GLMEs) to examine observational data on prey capture and tool use from 211 tagged individuals from five geographically defined study areas throughout the sea otter’s range in California. Our best supported model was able to explain 75% of the variation in the frequency of tool-use by individual sea otters with only ecological and demographic variables. In one study area, where sea otter food resources were abundant, all individuals had similar diets focusing on preferred prey items and used tools at low to moderate frequencies (4-38% of prey...
Categories: Data;
Tags: California,
USGS Science Data Catalog (SDC),
diet specialization,
foraging,
sea otter,
Three data sets are included here to aid in assessment of the sea otter population collapse in southwest Alaska. One data set consists of results of sea otter surveys conducted between 1959 and 2015 at Bering Island, Russia and a selection of western Aleutian Islands in Alaska. Sea otter counts are reduced to a comparable value of otters per linear kilometer. Another data set consists per-capita and per kilometer recovery rates of stranded sea otter carcasses from locations ranging from Bering Island, Russia, several Aleutian Islands, sites along the Alaska Peninsula, and Prince William Sound, Alaska. These data are mainly from the period 1991-2009 and are from stable populations as well as those in decline or post...
Categories: Data;
Tags: Eastern Aleutian Islands,
Gulf of Alaska,
Kodiak Island,
Prince William Sound,
USGS Science Data Catalog (SDC),
A standardized method to survey sea otters (Enhydra lutris nereis) was developed by WERC scientists and put into use in 1982 in California. Survey procedures involve counting animals during the "spring survey" -- generally beginning in April and ending in June or early July, depending on weather conditions. Two-person teams use binoculars and spotting scopes to count individuals from accessible stretches of coastline and from fixed-wing aircraft in the remaining areas. The counts made from shore are plotted on maps and then entered into a spatial database. The aerial counts are entered directly into a geographic information system-linked database in the aircraft. The survey records the total otter numbers, the...
The spring 2015 mainland sea otter count began on 2 May and wasn’t completed until 2 July. The delay in finishing the census was due primarily to limited availability of the survey plane (because of the need for the plane during the oil spill in the Refugio State Beach area). Overall viewing conditions this year were more favorable than those during the 2014 spring census (View Score = 2.6 vs. 2.3, where 0=poor, 1=fair, 2=good, 3=very good, and 4=excellent). The surface canopies of kelp (Macrocystis sp.) were considered by most participants to be about normal for this time of year. Sea otters along the mainland were surveyed (using a combination of ground-based and aerial-based surveys) from Pillar Point...
Categories: Data;
Tags: California,
Central California Coast,
Coast,
Southern California Coast,
USGS Science Data Catalog (SDC),
This data release is comprised of sea otter capture data from the capture of wild sea otters in Big Sur and Monterey, CA between the years of 2008-2011. These sea otters were captured for tagging and tracking during a comparison study designed to examine the biology, health, and survival of sea otters in a relatively pristine habitat (Big Sur) and a highly-impacted habitat (Monterey). At the time of capture a variety of data are collected on each individual sea otter. The otter may receive multiple identifiers including an otter number, color coded flipper tags, a PIT tag, VHF radio transmitter, and archival time-depth recorder. Capture information (date, time, GPS location and general area, capture team, capture...
Categories: Data;
Tags: Big Sur,
Monterey Bay,
USGS Science Data Catalog (SDC),
Wildlife Biology,
biota,
The GIS layer "Range_extent_15" 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 2015 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...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: California,
Central California Coast,
Coast,
Southern California Coast,
aerial counts,
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