A Dataset of Aerial Survey Counts of Harbor Seals in Iliamna Lake, Alaska: 1984-2013

Metadata Updated: March 26, 2021

This dataset provides counts of harbor seals from aerial surveys over Iliamna Lake, 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 phyiscal 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.

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 March 18, 2021
Metadata Created Date November 12, 2020
Metadata Updated Date March 26, 2021
Reference Date(s) February 3, 2015 (publication)
Frequency Of Update asNeeded

Metadata Source

Harvested from NMFS AFSC

Additional Metadata

Resource Type Dataset
Metadata Date March 18, 2021
Metadata Created Date November 12, 2020
Metadata Updated Date March 26, 2021
Reference Date(s) February 3, 2015 (publication)
Responsible Party (Point of Contact, Custodian)
Contact Email
Guid gov.noaa.nmfs.inport:24457
Access Constraints Cite As: Alaska Fisheries Science Center, [Date of Access]: A Dataset of Aerial Survey Counts of Harbor Seals in Iliamna Lake, Alaska: 1984-2013 [Data Date Range], https://www.fisheries.noaa.gov/inport/item/24457., Access Constraints: 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 | 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; Cite as: Withrow, David E., J.M. London, K.M. Yano, P.L. Boveng 2014. A Dataset of Aerial Survey Counts of Harbor Seals in Iliamna Lake, Alaska: 1984-2013 doi:10.7289/V5H41PCQ; | Distribution Liability: 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.
Bbox East Long -154.214
Bbox North Lat 59.7512
Bbox South Lat 59.5281
Bbox West Long -154.94
Coupled Resource
Frequency Of Update asNeeded
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.
Metadata Language eng
Metadata Type geospatial
Old Spatial {"type": "Polygon", "coordinates": [[[-154.94, 59.5281], [-154.214, 59.5281], [-154.214, 59.7512], [-154.94, 59.7512], [-154.94, 59.5281]]]}
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 1984-08-06
Temporal Extent End 2013-08-07

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