Annual California Sea Otter Census—2018 Spring Census Summary

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 ground-based survey of the sea otter population at San Nicolas Island was completed earlier in the spring (April 13–15) under fair to good survey viewing conditions (View Score = 1.5). Surface kelp canopies at San Nicolas Island were estimated to be near the seasonal normal. These data support the following U.S. Geological Survey Data Series:

Data and Resources

Field Value
accessLevel public
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identifier USGS:5b9a9e93e4b0d966b485dc8d
metadata_type geospatial
modified 20200830
old-spatial -122.423222821, 34.3902457219, -120.27277221, 37.2009909007
publisher U.S. Geological Survey
publisher_hierarchy Department of the Interior > U.S. Geological Survey
resource-type Dataset
source_datajson_identifier true
source_hash 1a85a2e3a73846ec6e8a11762ac61d72d27c344a
source_schema_version 1.1
spatial {"type": "Polygon", "coordinates": [[[-122.423222821, 34.3902457219], [-122.423222821, 37.2009909007], [ -120.27277221, 37.2009909007], [ -120.27277221, 34.3902457219], [-122.423222821, 34.3902457219]]]}
theme {geospatial}
Groups
  • AmeriGEOSS
  • National Provider
  • North America
Tags
  • aerial-counts
  • amerigeo
  • amerigeoss
  • biota
  • california
  • central-california-coastal
  • ckan
  • distribution
  • environment
  • geo
  • geoss
  • national
  • north-america
  • ocean
  • range
  • sea-otter-census
  • sea-otters
  • shore-counts
  • southern-california-coastal
  • united-states
  • usgs-5b9a9e93e4b0d966b485dc8d
isopen False
license_id notspecified
license_title License not specified
maintainer Brian B Hatfield
maintainer_email brian_hatfield@usgs.gov
metadata_created 2025-11-21T08:28:05.185960
metadata_modified 2025-11-21T08:28:05.185964
notes 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 ground-based survey of the sea otter population at San Nicolas Island was completed earlier in the spring (April 13–15) under fair to good survey viewing conditions (View Score = 1.5). Surface kelp canopies at San Nicolas Island were estimated to be near the seasonal normal. These data support the following U.S. Geological Survey Data Series:
num_resources 2
num_tags 21
title Annual California Sea Otter Census—2018 Spring Census Summary