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At-sea aerial survey species observations in southern California, 1999-2002

Metadata Updated: July 6, 2024

Broad survey lines, island radial survey lines, coastal survey lines, and focal-area (Santa Barbara Channel) survey lines were surveyed during each oceanographic season: spring (May), fall (September), and winter (January) during 1999 (May and September), 2000 (January, May, September), 2001 (January May, September), and 2002 (January). Aerial survey methods follow Mason et al. (2007). Specifically, we recorded all sightings of marine animals, vessels, and floating objects from twin-engine, high wing aircraft (Partenavia P-68s, Aspen Helicopters, Oxnard, CA, or California Department of Fish and Game) along pre-determined 100-meter (50 meters per side) strip transects at 60 meters above sea level. Surveys were flown at 160 kilometers per hour, and we used a Global Positioning System (GPS) unit linked to a laptop computer that allowed us to simultaneously collect coordinates (WGS-84 map datum), sea surface temperature (SST, degrees Celcius [°C]) determined via a belly-mounted, digital infrared radiation pyrometer (Heitronics™ KT19.85; measurement interval = 1 s, response time = 3 ms, emissivity = 0.99). SST values were appended to GPS flight data based on date and time. During individual surveys, observers frequently verified strip widths using hand-held clinometers. Observations generally were discontinued when glare exceeded greater than 25% of the field-of-view or if sea state exceeded Beaufort 5 (29–38 kilometers per hour wind speed). Observations were recorded into hand-held audio recorders. The third (non-dedicated) observer assisted the pilot with navigation, monitored sensor data, and maintained the onboard computer. The third observer also recorded incidental observations of marine mammals outside transects (i.e., non-standardized effort sightings). The effort for incidental marine mammal observations is not always consistent because the third observer was sometimes required to be engaged in other activities. Observations of species or individuals identified to nearest taxon included number of individuals, time, pre-coded behaviors, flight direction, and interspecies or vessel associations. Digital recordings of observations were archived and used by observers after surveys to enter data into a customized Graphical User Interface. Observation data were proofed after transcription to ensure accuracy or to resolve inconsistencies. Species observations were linked with GPS-based tracklines generated at 1 to 3 s intervals. Based on variations in the lag-time between sightings and recordings, we estimate that observations have a nominal along-trackline spatial accuracy of 222 meters, based on a five-second lag at 160 kilometers per hour survey speed. These data are associated with the following publication: Mason, J.W., McChesney, G.J., McIver, W.R., Carter, H.R., Takekawa, J.Y., Golightly, R.T., Ackerman, J.T., Orthmeyer, D.L., Perry, W.M., Yee, J.L. and Pierson, M.O. 2007. At-sea distribution and abundance of seabirds off southern California: a 20-Year comparison. Cooper Ornithological Society, Studies in Avian Biology Vol. 33.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date June 1, 2023
Metadata Updated Date July 6, 2024

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date June 1, 2023
Metadata Updated Date July 6, 2024
Publisher U.S. Geological Survey
Identifier USGS:57c761bfe4b0f2f0cebed538
Data Last Modified 20200827
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id f4c36c75-c91f-496d-b726-6b64f98ee78d
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -122.075873612,31.76840782,-117.11747222,36.329207841
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash 83e9e0ed331693c2bc321cc73c7c5d6e1a3f34a1deb10cae8915bae8902abd0b
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -122.075873612, 31.76840782, -122.075873612, 36.329207841, -117.11747222, 36.329207841, -117.11747222, 31.76840782, -122.075873612, 31.76840782}

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