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Alaska Harbor Seal Glacial Surveys

Metadata Updated: May 1, 2024

Floating glacial ice serves as a haul-out substrate for a significant number (10-15%) of Alaskan harbor seals, and thus surveying tidewater glacial fjords is an important component of statewide efforts to estimate seal abundance. Surveys conducted during pupping suggest that glacial haul outs have higher than average productivity and thus may serve as important source populations statewide. The availability of ice for hauling out varies with seasonal glacial dynamics, but over decades of climate change most tidewater glaciers are now retreating toward eventual grounding with many already ceasing to calve ice into the water. Compounding glacial retreat and thinning is the trend at most of these sites toward increasing tourism and a low compliance of tour vessels to seal approach guidelines and regulations. It is thus important to track glacial populations over the long-term especially as various impacts may degrade seal habitat leading to fewer glacial seals and potential impacts to the population state-wide.

There are currently 28 glacial sites that have at least one actively calving tidewater glacier and in turn seals that haul out on the ice during the seals’ molting period, when most surveys have occurred. Due to concerns about vessel disturbance, Disenchantment and Icy Bays have been surveyed during molting almost annually between 2001-2011 (ex 2003); surveys occurred during pupping and molting in 2004 and 2005, and have occurred just during molting apx. every other year since 2011. Johns Hopkins Inlet in Glacier Bay has been surveyed annually using these methods since 2007, with surveys occurring during both pupping and molting. The remaining 25 sites have been surveyed on an opportunistic schedule (based on weather and aircraft availability), which for most sites equates to about every 2-3 years. Some of the smallest sites have been surveyed on a 4-5 year schedule. These schedules will likely continue with more abundant sites in Prince William Sound (e.g., College Fjord and Columbia) and Southeast Alaska (Tracy Arm, Endicott Arm, LeConte Bay, and Glacier Bay) having higher priority and contingent on management concerns.

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 asNeeded

Metadata Source

Harvested from NMFS AFSC

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:17348
Access Constraints Cite As: Alaska Fisheries Science Center, [Date of Access]: Alaska Harbor Seal Glacial Surveys [Data Date Range], https://www.fisheries.noaa.gov/inport/item/17348., 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 -132
Bbox North Lat 61.5
Bbox South Lat 56.8
Bbox West Long -150.5
Coupled Resource
Frequency Of Update asNeeded
Harvest Object Id 3f5cc956-f55d-4924-8e22-d918d3e8fba3
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 AFSC’s current methods for surveying glacial fjords were first used in 2004, employing a cost-effective technique of high-resolution, vertical photography, using over-the-counter digital SLR cameras adapted to shoot vertically from a plane suitable for flying transects at 1000 feet in sometimes narrow glacial fjords. The resulting high-quality photographs (<4cm per pixel), which represent a sample of the ice habitat, produce spatial maps of seals which can then be used via statistical models to estimate density and ultimately abundance (with standard error). This technique, known as the LATTE method (short for Low AlTitude Transect Estimation), has been incrementally improved with higher resolution cameras (from 10 to 25 MP), faster, more accurate GPS’s to aid in transect navigation, and a system that has a 3-camera, forward motion-compensating camera system to increase coverage and reduce flight time.
Metadata Language eng
Metadata Type geospatial
Old Spatial {"type": "Polygon", "coordinates": [[[-150.5, 56.8], [-132.0, 56.8], [-132.0, 61.5], [-150.5, 61.5], [-150.5, 56.8]]]}
Progress underDevelopment
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 2004
Temporal Extent End 2011

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