A Dataset of Aerial Survey Counts of Harbor Seals in Iliamna Lake, Alaska: 1984-2013

Description

This dataset provides counts of harbor seals from aerial surveys over Iliamna Lake, Alaska, USA. The data have been collated from three previously published sources (Mathisen and Kline 1992; Small 2001; ABR Inc. Environmental Research and Services 2011) and newly available data from the NOAA Alaska Fisheries Science Center and the Newhalen Tribal Council. The survey years range between 1984 and 2013. Counts are reported as summed totals across all identified waypoints in the lake for each survey date. The NOAA National Marine Mammal Laboratory (NMML) (Alaska Fisheries Science Center, Seattle, Washington, USA) conducted aerial surveys of Iliamna Lake between 2008 and 2013. Surveys were conducted as part of annual harbor seal survey effort and in collaboration with local community participants and researchers at the University of Alaska. Surveys were flown using high wing, twin engine aircraft (Aero Commander 680, 690 or a de Havilland Twin Otter). Survey altitude was generally 330 m and at an aircraft speed of 120 kts. Surveys were performed seasonally for most years between 2008 and 2013. Surveys were timed so that one survey was conducted while the lake was mostly frozen (Late March/early April), one during pupping (mid July), and often several during the August molt, when the greatest number of seals typically haul out on shore. Surveys were flown, weather allowing, in the mid- to late-afternoon, when the number of seals hauled out was expected to be highest. Aircraft flight track was recorded by GPS and all seals sighted were digitally photographed using a high resolution digital SLR camera with a telephoto zoom lens (up to 400mm). Time, date, latitude, longitude, and altitude were automatically saved into the image metadata or georeferenced post survey using the GPS track and software. The total number of seals hauled out were counted from the digital photographs and recorded for each identified site. Pups were determined by their smaller size, and close proximity (less than 1 body length; either nursing or laying right next) to a larger seal. Pups were no longer recorded beyond about mid-August when many have been weaned and cannot reliably be distinguished from other non-adult seals. In 2009, a collaborative effort between NMML and researchers from the Newhalen Tribal Council (Newhalen Tribal Council 2009) provided 10 additional surveys and similar techniques were used. The raw survey count data from these surveys was provided to NMML. Aerial surveys were authorized under a Marine Mammal Protection Act General Authorization (LOC No. 14590) issued to the NMML. Between 2005 and 2007, ABR, Inc. Environmental Research and Services conducted a series of aerial surveys for harbor seals in Iliamna Lake (ABR Inc. Environmental Research and Services 2011). In addition, earlier counts from surveys conducted by ADFG (Small 2001) and a 1991 census by Mathisen and Kline (Mathisen and Kline 1992) were incorporated into the dataset to expand the historical reach. Geographic coordinates were provided (or, when not provided, determined based on descriptions or phyiscal maps) for each survey site and these sites were compared and merged with locations identified by NMML. In some cases, sites in very close geographic proximity were combined into a single site.

Resources

Name Format Description Link
0 View the complete metadata record on InPort for more information about this dataset. https://www.fisheries.noaa.gov/inport/item/24457
0 AKFSC Home Page https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
0 Digital Object Identifier http://dx.doi.org/10.7289/V5H41PCQ
0 NCEI Landing Page http://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.nodc:0123188
33 NOAA Data Management Plan for this record on InPort. https://www.fisheries.noaa.gov/inportserve/waf/noaa/nmfs/afsc/dmp/pdf/24457.pdf
0 https://noaa-fisheries-afsc.data.socrata.com/Species/A-Dataset-of-Aerial-Survey-Counts-of-Harbor-Seals-/dfm6-zu9q
0 https://accession.nodc.noaa.gov/download/123188
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
0 https://accession.nodc.noaa.gov/download/123188
0 https://noaa-fisheries-afsc.data.socrata.com/Species/A-Dataset-of-Aerial-Survey-Counts-of-Harbor-Seals-/dfm6-zu9q
0 View the complete metadata record on InPort for more information about this dataset. https://www.fisheries.noaa.gov/inport/item/24457
0 AKFSC Home Page https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
0 Digital Object Identifier http://dx.doi.org/10.7289/V5H41PCQ
0 NCEI Landing Page https://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.nodc:0123188
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/24457.pdf
0 https://accession.nodc.noaa.gov/download/123188
0 https://noaa-fisheries-afsc.data.socrata.com/Species/A-Dataset-of-Aerial-Survey-Counts-of-Harbor-Seals-/dfm6-zu9q
0 View the complete metadata record on InPort for more information about this dataset. https://www.fisheries.noaa.gov/inport/item/24457
0 AKFSC Home Page https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
0 Digital Object Identifier http://dx.doi.org/10.7289/V5H41PCQ
0 NCEI Landing Page https://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.nodc:0123188
0 Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 22. 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/24457.pdf

Tags

  • alaska fisheries science center
  • alaska
  • iliamna lake
  • harbor seal
  • noaa
  • u.s. department of commerce
  • national marine fisheries service
  • doc/noaa/nmfs/afsc
  • abundance
  • alaska harbor seal surveys and abundance
  • aerial survey

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