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

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.

The purpose of this dataset is to provide an archive of harbor seal counts collected as part of an extensive effort by the Alaska Department of Fish and Game (ADFG) in collaboration with the Polar Ecosystems Program (PEP). The data were provided to the Alaska Fisheries Science Center by ADFG and are a key foundation for assessment of abundance and long term trends.

Small, R, G. Pendleton, K. Pitcher, K. Wynne, K. Frost, K. McAlister, B. Mathews, J. Womble, and G. Blundell (2015): Aerial Survey Trend Counts of Harbor Seals in Coastal Alaska (1984-2006) - ADF&G. Alaska Department of Fish and Game. --doi:TBD, contact authors for updated citation details--

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.

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. Acknowledge NOAA/NMFS/AFSC 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 prior to use.

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.

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.

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.

no metadata access constraints

Metadata are subject to revision at any time and information within the metadata record should not be cited without author consent. 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.

This dataset has been the foundation of at least one peer-reviewed and published study. As such, the data have been subjected quality control and quality assurance procedures associated with the statistical analysis and both internal and external review processes.

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IT Security and Contingency Plan for the system establishes procedures and applies to the functions, operations, and resources necessary to recover and restore data as hosted in the Western Regional Support Center in Seattle, Washington, following a disruption.

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).