Bering Sea Helicopter Surveys for Ice-Associated Seals (2007-08)

Description

In the spring of 2007 and 2008, researchers from the Alaska Fisheries Science Center conducted aerial surveys for ribbon, bearded, and spotted seals in the US sector of the Bering Sea. The surveys were conducted from helicopters based aboard the US Coast Guard icebreakers Healy and Polar Sea. Line transect surveys were conducted between approximately 09:00 and 16:00 (local solar time), which corresponds to the timing of peak seal haul-out probability. By local solar time, we mean that for each 15° of latitude west of 0 degrees longitude, one hour was subtracted; thus, we used UTC minus 11 h for Bering Sea observations which puts the sun overhead at approximately noon at these coordinates. Each flight had two to three observers and was flown at a target altitude of 118m (400 ft) at speeds of 80–95 knots. Only seals hauled out on ice were observed and recorded. The distance from each seal to the helicopter’s track line was calculated using a sighting bar mounted on each observer’s window. In all, 2214 seals were observed during approximately 73 h of survey effort covering 11819 km of survey line on 63 flights. Because ice conditions decayed markedly toward the end of the 2007 surveys, our analysis used only the first 27 flights. The number of ringed seal sightings was low, possibly due to a combination of a preponderance of survey effort away from near-shore areas favored by ringed seals and a greater tendency for ringed seals to be disturbed into the water by the helicopter, and therefore to be missed by observers.

Resources

Name Format Description Link
0 Data are available online as supplemental material associated with the publication: http://www.esapubs.org/archive/ecol/E094/239/suppl-1.php (see "File list" section) http://www.esapubs.org/archive/ecol/E094/239/suppl-1.php
0 View the complete metadata record on InPort for more information about this dataset. https://www.fisheries.noaa.gov/inport/item/17354
0 AKFSC Home Page https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
0 Digital Object Identifier http://dx.doi.org/10.1016/j.stamet.2013.03.001
33 NOAA Data Management Plan for this record on InPort. https://www.fisheries.noaa.gov/inportserve/waf/noaa/nmfs/afsc/dmp/pdf/17354.pdf
21 Online Resource http://www.afsc.noaa.gov/Quarterly/amj2008/divrptsNMML3.htm
0 The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. https://www.earthdata.nasa.gov/learn/find-data/idn/gcmd-keywords
21 Online Resource http://www.afsc.noaa.gov/Quarterly/amj2007/divrptsNMML3.htm
0 Data are available online as supplemental material associated with the publication: http://www.esapubs.org/archive/ecol/E094/239/suppl-1.php (see "File list" section) http://www.esapubs.org/archive/ecol/E094/239/suppl-1.php
0 View the complete metadata record on InPort for more information about this dataset. https://www.fisheries.noaa.gov/inport/item/17354
0 AKFSC Home Page https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
0 Digital Object Identifier http://dx.doi.org/10.1016/j.stamet.2013.03.001
21 Online Resource https://www.afsc.noaa.gov/Quarterly/amj2007/divrptsNMML3.htm
21 Online Resource https://www.afsc.noaa.gov/Quarterly/amj2008/divrptsNMML3.htm
0 Global Change Master Directory (GCMD). 2024. GCMD Keywords, Version 19. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords
33 NOAA Data Management Plan for this record on InPort. https://www.fisheries.noaa.gov/inportserve/waf/noaa/nmfs/afsc/dmp/pdf/17354.pdf

Tags

  • bearded seal
  • alaska fisheries science center
  • alaska
  • ribbon seal
  • distribution
  • noaa
  • ringed seal
  • u.s. department of commerce
  • 2007-2008 bering sea ice seal surveys
  • national marine fisheries service
  • doc/noaa/nmfs/afsc
  • abundance
  • line-transect survey
  • spotted seal
  • bering sea

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