Aerial Survey Counts of Harbor Seals in Coastal Alaska (2003-2011)

This dataset supports efforts to estimate the abundance and trends in population size of Alaska harbor seals. Annual surveys of harbor seal populations are fundamental to estimation of seal abundance, distribution, and trends, which in turn are essential for stock assessment, conservation, and management. The most feasible approach to determining harbor seal distribution and abundance is to use aircraft to count seals when they haul out of the water and are visible. Harbor seals in Alaska occupy a geographically extensive range from approximately long. 172ºE to 130ºW (over 3,500 km east to west) and from lat. 51ºN to 61.5ºN (over 1,000 km north to south). Estimation of the abundance of harbor seals statewide requires broad-scale aerial surveys and these surveys have been conducted by NOAA Fisheries, the Alaska Department of Fish and Game, and other collaborators since the early 1980s. This dataset reflects counts of harbor seals from surveys conducted between 2003 and 2011.

This dataset differs from earlier datasets in a few key areas: 1) records generally correspond to a count of the number of harbor seals within a single, geo-referenced digital photo, 2) photographs were not taken when no seals were present so additional analysis of survey effort and flight tracks was required to determine 0 counts.

The purpose of this dataset is to provide a single collection of harbor seal counts from aerial surveys conducted in Alaska between 2003 and 2011.

London, J.M., K.M. Yano, D.E. Withrow, J.K. Jansen, S.P. Dahle, H.L. Ziel, G.M. Brady, M.F. Cameron, J.M. Ver Hoef, and P.L. Boveng (2015): Aerial Survey Counts of Harbor Seals in Coastal Alaska (2004-2011). Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration. --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.

Data represented in this dataset are the result of a culmination of multiple observations, data collection protocols and spatial analysis. Through the process various checks are performed to insure data are of the highest quality. These include, but are not limited to: collection of geographic coordinates with high resolution GPS units, high resolution navigational systems on board the aircraft, the use of high resolution DSLR cameras and quality lenses, synching camera time with GPS provided time, and counting of photographs on large, high quality screens with modern software. Despite these quality control checks, users of these data must understand the data are often collected under challenging field conditions and additional processing and testing must be done before these data can be used appropriately.

data are not automatically processed

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.

Data collection and processing protocols were updated and improved on a nearly annual basis during the 2003-2011 period. For example, aerial survey observers transitioned from using paper maps and rudimentary GPS units to using advanced GPS units and moving map software on laptop computers for in-flight navigation and data recording purposes. 35 mm film cameras were replaced by digital SLR cameras with new, higher-resolution models being added every few years. And the seal counting process transitioned from projecting slides on a white board to using computers with photo-processing software and high-resolution monitors to mark and count individual seals. In most cases, records within this dataset represent seal counts within a single, geo-referenced photograph taken by a trained observer during dedicated aerial surveys for harbor seals.