| Bi-Annual Sea Otter Counts |
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| Written by Mike Harris | |
| Tuesday, 21 November 2006 | |
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Since 1982,
a standardized method has been deployed to survey the sea otter population in California. The entire sea otter range is surveyed twice
annually, in early fall and late spring. The spring surveys have traditionally been
used to assess population status because they are both consistently higher than
fall surveys and show less variability.
The fall survey data supplements the spring data to provide the
necessary information to assess female reproductive rates and changes in
reproductive success of the California sea otter population through time. The current survey area extends along approximately
630 kilometers (395 miles) of coastline from Point San Pedro, San Mateo County southward to Rincon Point, Santa Barbara County.
The survey methodology consists of two-person teams using binoculars and
spotting scopes that survey nearshore waters along accessible stretches of
coastline. A Fixed-wing aircraft (Partenavia
PN68 Observer) with two observers, a data recorder and pilot conduct aerial
surveys of the remaining areas. The
aerial method is used to survey sections of the sea otter range that are not amenable
to shore-based counts either because of accessibility, topography, or distance
of animals from shore. Approximately 60%
of the survey area is counted by the aerial method. 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 used in the
aircraft. These rangewide sea otter surveys are conducted cooperatively by
scientists of the U.S. Geological Survey, California Department of Fish and Game, U.S. Fish and Wildlife Service, Monterey
Bay Aquarium and with the help of experienced volunteers. The information
gathered will be used by federal and state wildlife agencies to monitor trends
in population dynamics and in making decisions about the management of this threatened
species.
 Sea Otter Shore Based Survey  Sea Otter Shore Based Survey  Sea Otter Shore Based Survey  Sea Otter Aerial Survey  Sea Otter Aerial Survey  Sea Otter Survey Transects  Sea Otter Survey Plane
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| Last Updated ( Wednesday, 08 August 2007 ) |
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