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    • Aerial Survey Trend Counts of Harbor Seals in Coastal Alaska (1984-2006) - ADF&G

    Metadata Updated: May 1, 2024

    Aerial surveys were conducted during 1983–2006 in the Ketchikan, Sitka, Kodiak, and Bristol Bay areas of Alaska to estimate trends in abundance of harbor seals.

    Access & Use Information

    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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    Dates

    Metadata Date April 17, 2024
    Metadata Created Date May 1, 2024
    Metadata Updated Date May 1, 2024
    Reference Date(s) (publication)
    Frequency Of Update notPlanned

    Metadata Source

    Harvested from NMFS AFSC

    Other Data Resources

    Additional Metadata

    Resource Type Dataset
    Metadata Date April 17, 2024
    Metadata Created Date May 1, 2024
    Metadata Updated Date May 1, 2024
    Reference Date(s) (publication)
    Responsible Party (Point of Contact, Custodian)
    Contact Email
    Guid gov.noaa.nmfs.inport:26619
    Access Constraints Cite As: Alaska Fisheries Science Center, [Date of Access]: Aerial Survey Trend Counts of Harbor Seals in Coastal Alaska (1984-2006) - ADF&G [Data Date Range], https://www.fisheries.noaa.gov/inport/item/26619., Access Constraints: The data set is in the process of being archived with the NOAA National Centers for Environmental Information. Once the archival process is complete and verified, the data set will be publicly available., Use Constraints: User must read and fully comprehend the metadata prior to use. Applications or inferences derived from the data should be carefully considered for accuracy. While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty. Acknowledge NOAA/NMFS/AFSC or the specified citation as the source from which these data were obtained in any publications and/or other representations of these data. Communication and collaboration with dataset authors is strongly encouraged., Distribution Liability: While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
    Bbox East Long -130
    Bbox North Lat 62
    Bbox South Lat 54
    Bbox West Long -166
    Coupled Resource
    Frequency Of Update notPlanned
    Harvest Object Id 07680720-55bb-450c-8d9e-0b14da555e9c
    Harvest Source Id 26a29bb9-50b0-47fd-920b-edc74aa6ec76
    Harvest Source Title NMFS AFSC
    Licence NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
    Lineage The Ketchikan and Sitka aerial trend routes were first surveyed in 1983 and 1984 (Pitcher, unpublished data), followed by only one additional survey of the Ketchikan route in 1988 (Pitcher, unpublished data) prior to consecutive annual surveys beginning in 1994 for Ketchikan and 1995 for Sitka. Beginning in 1998, ADF&G surveyed the Ketchikan route biennially due to low variation associated with an estimated long-term increasing trend (Small, unpublished data). The Kodiak and Bristol Bay trend routes were established in 1993 and 1998, respectively, and surveyed through 2006. Haul-out sites within the Ketchikan and Sitka routes were selected primarily because they represented the large majority of sites within a logical flight sequence and could be surveyed within approximately 4 h from an airport; sites with few (<5) seals were not included. For the Kodiak and Bristol Bay routes, all haul-out sites along a relatively extensive coastline were selected. Specifically, all sites on the east side of Kodiak Island from Chiniak Bay (near Kodiak) south to Tugidak Island were included in the Kodiak route, whereas in Bristol Bay all sites between Kvichak Bay and Port Moller on the north side of the Alaska Peninsula were included. The sites within Herendeen Bay and the southeast arm of Port Moller were not included in the Bristol Bay route because the number of seals using those sites was relatively much smaller compared to sites nearer the open waters of Bristol Bay, and their inclusion would increase the duration of the survey substantially. Prince William Sound was first flown in 1984 and then annually from 1988 through 2006. Each trend route consisted of 16-34 harbor seal haul-out sites that were surveyed with either single- or twin-engine aircraft during the molting period between mid- August and early September. Surveys usually were conducted between 2 h either side of the low tide, at an altitude of 200-300 m unless weather conditions required lower altitudes; surveys were not conducted during heavy rain or strong winds. After locating hauled-out seals, the pilots circled the site and the observer visually counted all seals (including those in the water near haul-outs), using binoculars when necessary, and then photographed sites using either 35-mm color slide film (ASA 400) or digital images and a 80-200-mm zoom lens for groups of >10-15 seals. We recorded the time when seals at each site were counted, so that tide height at each site during the survey could later be estimated based on tide data from the nearest tide station. Survey times were not recorded for the 1983 Sitka survey, and therefore those counts are not included in our analysis. We attempted to conduct five to seven replicate surveys per year for each route, with each site surveyed unless prohibited by poor weather. Seals were later counted from projected slide images on a white surface or from a computer monitor for digital images. The replicate counts for each trend site were reported previously (Small, unpublished data).
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Polygon", "coordinates": [[[-166.0, 54.0], [-130.0, 54.0], [-130.0, 62.0], [-166.0, 62.0], [-166.0, 54.0]]]}
    Progress completed
    Spatial Data Service Type
    Spatial Reference System
    Spatial Harvester True
    Temporal Extent Begin 1984
    Temporal Extent End 2006

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