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The GIS shapefile "Census summary of southern sea otter 2017" 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 2017 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...
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The GIS shapefile "Extra limit observations 2016" 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 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...
Two data sets concerning organic contaminants are included here to aid in assessment of the sea otter population collapse in southwest Alaska. One data set consists of levels of organic pollutant compounds found in wild sea otter blood collected from captured animals in 1997 (Jessup et al., 2010). These sea otters were captured from islands in the western Aleutians and from outside the area of population collapse, in southeast Alaska near Cross Sound. Another data set consists of levels of organic pollutant compounds found in blue mussels collected from multiple sites along the Aleutian archipelago and from the Cross Sound area in southeast Alaska in 1994-1996 (Reese et al., 2012). These data support the following...
The table presents summary data of sea otter skulls found on carcass searches conducted along stretches of shoreline at islands or locations along a longitudinal span encompassing the sea otter population decline. Numbers of skulls encountered, length of shoreline searched, population density calculated from survey data, as well as skulls per kilometer and per-capita recovery rate are presented. The data are arranged in west to east order from Bering Island to Prince William Sound.
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The GIS shapefile "Extra limit counts of southern sea otters 2017" 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 2017 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...
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The spring 2018 mainland sea otter count began on April 26, and was completed by May 24, 2018. Overall viewing conditions this year were good and rounded off to the same conditions experienced during the 2017 spring census (View Score 2.4, 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 above normal for this time of year in most areas of the mainland range, and considerably above what was encountered during the 2017 spring census. Sea otters along the mainland coast were surveyed from Pillar Point in San Mateo County in the north to Rincon Point in the south at the Santa Barbara/Ventura County line. A separate...
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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...


map background search result map search result map Annual California Sea Otter Census: 2016 Extra limit observations shapefile Annual California Sea Otter Census: 2017 Census Summary Shapefile Annual California Sea Otter Census: 2017 Extra Limit Observations Shapefile Annual California Sea Otter Census - 2018 Spring Census Summary Annual California Sea Otter Census: 2018 Range Extent Shapefile Sea otter carcass recovery rates from Bering Island, some Western Aleutian Islands, the Alaskan Peninsula and Prince William Sound, 1971-2009 Persistent Organic Pollutants in Sea Otter Blood and in Blue Mussels from the Aleutian Islands and Southeast Alaska Annual California Sea Otter Census: 2017 Extra Limit Observations Shapefile Annual California Sea Otter Census: 2018 Range Extent Shapefile Annual California Sea Otter Census: 2017 Census Summary Shapefile Annual California Sea Otter Census - 2018 Spring Census Summary Persistent Organic Pollutants in Sea Otter Blood and in Blue Mussels from the Aleutian Islands and Southeast Alaska Sea otter carcass recovery rates from Bering Island, some Western Aleutian Islands, the Alaskan Peninsula and Prince William Sound, 1971-2009