Aerial Survey Counts of Harbor Seals in Lake Iliamna, Alaska, 1984-2013 (NODC Accession 0123188)

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This dataset provides counts of harbor seals from aerial surveys over Lake Iliamna, 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 phyiscial 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.

The iliamna_totalcounts file provides counts (n=96) and observed weather conditions for each survey date. Both total number of adult seals (adulttotal) and total number of identified pups (puptotal) are provided when available. puptotal is recorded as NA when adults and pups were not distinguished. In these cases, the adulttotal value is presumed to include pups. In addition to the seal count inforamtion, each record includes observed weather variables (airtemp (in ranges of degrees F), windspeed (in ranges of miles per hour), winddirection (cardinal), and descriptive categories for skycondition and precip). The datetime values correspond to local Alaska time.
  • Cite as: Withrow, David E.; London, Josh M.; Yano, Kymberly M.; Boveng, Peter L. (2015). Aerial Survey Counts of Harbor Seals in Lake Iliamna, Alaska, 1984-2013 (NODC Accession 0123188). Version 2.3. National Oceanographic Data Center, NOAA. Dataset. doi:10.7289/V5H41PCQ [access date]
gov.noaa.nodc:0123188
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  • Originator data format
Ordering Instructions Data may be searched and downloaded using online services provided by NCEI using the online resource URLs in this record. Contact NCEI Information Services for custom orders. When requesting data from NCEI, the desired data set may be referred to by the unique package identification number listed in this metadata record.
Distributor DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
Dataset Point of Contact Information Services
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
Time Period 1984-08-06 to 2013-08-07
Spatial Bounding Box Coordinates
N: 59.7512
S: 59.5281
E: -154.214
W: -154.94
Spatial Coverage Map
General Documentation
Associated Resources
Publication Dates
  • publication: 2015-01-22
  • revision: 2015-06-18
Edition 2.3
Data Presentation Form Digital table - digital representation of facts or figures systematically displayed, especially in columns
Dataset Progress Status Complete - production of the data has been completed
Data Update Frequency As needed
Supplemental Information
In this accession, NCEI has archived multiple versions of these data. The latest (and best) version of these data has the largest version number.
Purpose Basic research
Use Limitations
  • accessLevel: Public
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Dataset Citation
  • Cite as: Withrow, David E.; London, Josh M.; Yano, Kymberly M.; Boveng, Peter L. (2015). Aerial Survey Counts of Harbor Seals in Lake Iliamna, Alaska, 1984-2013 (NODC Accession 0123188). Version 2.3. National Oceanographic Data Center, NOAA. Dataset. doi:10.7289/V5H41PCQ [access date]
Cited Authors
  • Withrow, David E.
  • London, Josh M.
  • Yano, Kymberly M.
  • Boveng, Peter L.
Contributors
Resource Providers
Publishers
Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
Global Change Master Directory (GCMD) Science and Services Keywords
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > SURFACE WINDS > WIND DIRECTION
  • EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > SURFACE WINDS > WIND SPEED
  • EARTH SCIENCE > ATMOSPHERE > PRECIPITATION
  • EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > MAMMALS
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NESDIS/NODC > National Oceanographic Data Center, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NMFS/AFSC/NMML > National Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, U.S. Department of Commerce
NODC COLLECTING INSTITUTION NAMES THESAURUS NODC SUBMITTING INSTITUTION NAMES THESAURUS
Instrument keywords NODC INSTRUMENT TYPES THESAURUS
Place keywords NODC SEA AREA NAMES THESAURUS Global Change Master Directory (GCMD) Location Keywords
  • OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN
Keywords NCEI ACCESSION NUMBER
Use Constraints
  • Cite as: Withrow, David E.; London, Josh M.; Yano, Kymberly M.; Boveng, Peter L. (2015). Aerial Survey Counts of Harbor Seals in Lake Iliamna, Alaska, 1984-2013 (NODC Accession 0123188). Version 2.3. National Oceanographic Data Center, NOAA. Dataset. doi:10.7289/V5H41PCQ [access date]
Access Constraints
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Lineage information for: dataset
Processing Steps
  • 2015-01-22T20:14:06 - NCEI Accession 0123188 v1.1 was published.
  • 2015-05-04T23:53:11 - NCEI Accession 0123188 was revised and v1.2 was published.
    Rationale: Updates were received for this data set. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession.
  • 2015-06-18T19:14:14 - NCEI Accession 0123188 was revised and v2.3 was published.
    Rationale: Updates were received for this data set. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession.
Output Datasets
Lineage information for: repository
Processing Steps
  • 2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
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Instrument
  • visual analysis
Last Modified: 2018-08-10T18:56:51
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