Skip to main content
Dataset Overview | National Centers for Environmental Information (NCEI)

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

browse graphicPreview graphic
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 physical 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 information, 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 (NCEI Accession 0123188). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.7289/v5h41pcq. Accessed [date].
gov.noaa.nodc:0123188
Download Data
  • HTTPS (download)
    Navigate directly to the URL for data access and direct download.
  • FTP (download)
    These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP).
Distribution Formats
  • Originator data format
Ordering Instructions Contact NCEI for other distribution options and instructions.
Distributor NOAA National Centers for Environmental Information
+1-301-713-3277
NCEI.Info@noaa.gov
Dataset Point of Contact NOAA National Centers for Environmental Information
ncei.info@noaa.gov
Time Period 1984-08-06 to 2013-08-07
Spatial Bounding Box Coordinates
West: -154.94
East: -154.214
South: 59.5281
North: 59.7512
Spatial Coverage Map
General Documentation
Associated Resources
  • Alaska Fisheries Science Center, 2015: A Dataset of Aerial Survey Counts of Harbor Seals in Iliamna Lake, Alaska: 1984-2013, https://www.fisheries.noaa.gov/inport/item/24457.
Publication Dates
  • publication: 2015-01-22
  • revision: 2015-06-18
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
Historical archive - data has been stored in an offline storage facility
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 This dataset is available to the public for a wide variety of uses including scientific research and analysis.
Use Limitations
  • accessLevel: Public
  • Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
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 (NCEI Accession 0123188). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.7289/v5h41pcq. Accessed [date].
Cited Authors
Contributors
Resource Providers
Publishers
Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
Global Change Master Directory (GCMD) Science Keywords
Data Center keywords NODC COLLECTING INSTITUTION NAMES THESAURUS NODC SUBMITTING INSTITUTION NAMES THESAURUS Global Change Master Directory (GCMD) Data Center Keywords
Instrument keywords NODC INSTRUMENT TYPES THESAURUS
Place keywords NODC SEA AREA NAMES THESAURUS Global Change Master Directory (GCMD) Location Keywords
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 (NCEI Accession 0123188). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.7289/v5h41pcq. Accessed [date].
Access Constraints
  • Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
Fees
  • In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media.
Lineage information for: dataset
Processing Steps
  • 2015-01-22T20:14:05Z - NCEI Accession 0123188 v1.1 was published.
  • 2015-05-04T23:53:10Z - NCEI Accession 0123188 was revised and v1.2 was published.
    Rationale: Additional metadata files were received or created for this dataset. These updates were copied into the about/ 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.
  • 2015-06-18T19:14:13Z - NCEI Accession 0123188 was revised and v2.3 was published.
    Rationale: Updates were received for this dataset. 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.
Acquisition Information (collection)
Instrument
  • visual analysis
Last Modified: 2024-01-02T12:15:45Z
For questions about the information on this page, please email: ncei.info@noaa.gov