This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) and reported breeding areas of spotted seals (Phoca largha). It was produced as part of a U.S. Endangered Species Act status review, which included delineating the species in question and assessing its risk of extinction within the foreseeable future throughout all or a significant portion of its range. Its boundaries are based on previously published range maps and/or descriptions of the species' distribution in published or unpublished accounts. All boundaries should be considered approximate.

This dataset contains GIS layers that depict the known spatial distributions (i.e., ranges) and reported breeding areas of ribbon seals (Histriophoca fasciata). It was produced as part of a U.S. Endangered Species Act status review, which included delineating the species in question and assessing its risk of extinction within the foreseeable future throughout all or a significant portion of its range. Its boundaries are based on previously published range maps and/or descriptions of the species' distribution in published or unpublished accounts. All boundaries should be considered approximate

This dataset contains information regarding the capture and tagging of northern fur seals on the Pribilof Islands and Bogoslof Island, Alaska, from 1992 to 2017.

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.

These data sets were used by Zeppelin et al. (2015) to model northern fur seal foraging habitats based on stable isotope values measured in plasma and red blood cells, and satellite-linked tag measures of locations and diving behavior. Foraging habitat models were developed using blood isotope samples collected from 35 adult female fur seals on three breeding colonies in Alaska during July-October 2006. Satellite location and dive data were used to define habitat use in terms of the proportion of time spent or dives made in different oceanographic/bathymetric domains. Stable isotope samples, dive data, and GPS location data collected from 15 females during August-October 2008 validated model use across years.

This data layer represents the 12 uniquely identified stocks of harbor seals found in Alaskan waters. Stocks were identified by NMFS and their co-management partners, the Alaska Native Harbor Seal Commission, in 2010 based largely on genetic structure. Given the genetic samples were not obtained continuously throughout the range, a total evidence approach was used to consider additional factors such as population trends, observed harbor seal movements, and traditional Alaska Native use areas in the final designation of stock boundaries. The 12 stocks of harbor seals currently identified in Alaska are 1) the Aleutian Islands, 2) the Pribilof Islands, 3) Bristol Bay, 4) North Kodiak Island, 5) South Kodiak Island, 6) Prince William Sound, 7) Cook Inlet/Shelikof Strait, 8) Glacier Bay/Icy Strait, 9) Lynn Canal/Stephens Passage, 10) Sitka/Chatham Strait, 11) Dixon/Cape Decision and 12) Clarence Strait.

Aerial surveys of coastal Alaska are the primary method for estimating abundance of harbor seals. A particular challenge associated with aerial surveys of harbor seals is maintaining consistent spatial representation of haulout locations. In some cases, seals aggregate into a single large grouping at a particular area. In other cases, seals aggregate into several smaller groups spread over a particular area. To establish geo-spatial consistency, the Alaska Fisheries Science Center developed coastal survey units (spatial polygons) throughout the distriubtion of harbor seals in Alaska. Each survey unit was designed to be approximately 10-15 kilometers in coastal length, to faciliate efficient aerial surveys, and to aggregate known harbor seal haulout locations. Each survey unit was assigned a unique alphanumeric identifier and the spatial data are provided in the geographic (epsg:4326) coordinate reference system. The survey units form the spatial foundation for estimation of harbor seal abundance and trend.

In the spring of 2007 and 2008, researchers from the Alaska Fisheries Science Center conducted aerial surveys for ribbon, bearded, and spotted seals in the US sector of the Bering Sea. The surveys were conducted from helicopters based aboard the US Coast Guard icebreakers Healy and Polar Sea. Line transect surveys were conducted between approximately 09:00 and 16:00 (local solar time), which corresponds to the timing of peak seal haul-out probability. By local solar time, we mean that for each 15° of latitude west of 0 degrees longitude, one hour was subtracted; thus, we used UTC minus 11 h for Bering Sea observations which puts the sun overhead at approximately noon at these coordinates. Each flight had two to three observers and was flown at a target altitude of 118m (400 ft) at speeds of 80–95 knots. Only seals hauled out on ice were observed and recorded. The distance from each seal to the helicopter’s track line was calculated using a sighting bar mounted on each observer’s window. In all, 2214 seals were observed during approximately 73 h of survey effort covering 11819 km of survey line on 63 flights. Because ice conditions decayed markedly toward the end of the 2007 surveys, our analysis used only the first 27 flights. The number of ringed seal sightings was low, possibly due to a combination of a preponderance of survey effort away from near-shore areas favored by ringed seals and a greater tendency for ringed seals to be disturbed into the water by the helicopter, and therefore to be missed by observers.

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.

US surveys were conducted of the Bering Sea pack ice for bearded, spotted, ribbon, and ringed seals using digital cameras and thermal imagers mounted in the belly ports of two fixed-wing aircraft from 6 April to 23 May 2012 and 4 April to 9 May 2013. U.S. flights were flown at a target altitude of 1,000 ft (300 m) to maximize the area surveyed while maintaining the required imaging resolution and minimizing the chance of disturbance to seals and other wildlife. A NOAA Twin Otter (N56RF) aircraft housed three FLIR SC645 thermal imagers, which recorded continuous data in the 7.5-13.0 µm wavelength. Each thermal imager was paired with a Canon Mark III 1Ds digital single-lens reflex camera fitted with a 100-mm Zeiss lens. All six instruments were mounted in an open-air belly port. The combined thermal swath width was approximately 1,500 ft (470 m) at an altitude of 1,000 ft. A contracted Aero Commander aircraft carried two sets of paired thermal imagers (SC645) and digital SLR cameras (Nikon D3X) and surveyed a maximum swath width of approximately 900 ft (280 m). Color cameras collected images at a 1-1.2 second interval. In 2013 the two aircraft flew a total of 36 surveys covering more than 17,000 nmi (32,090 km) of trackline and collected about 913,000 images. Combined with the 2012 survey effort, the U.S. BOSS team covered 31,000 nmi of trackline and collected 1.8 million images.