These data are part of North Pacific Research Board Project 414 and Project 514. Project 514 provided a second year of data collection to the study detailed in Banks et al. (2006; North Pacific Research Board Project 414 Final Report; https://workspace.aoos.org/published/file/48ffae91-0274-4b2b-bc84-5378554070c1/f0414_final_report.pdf?source=catalog&portalId=92), and are summarized together in Springer et al. (2008; North Pacific Research Board Project 514 Final Report; https://workspace.aoos.org/files/2580819/514_Final%20report.pdf?source=catalog&portalId=92 Adult female northern fur seals were captured with hoop nets at 2 breeding colonies (Reef and Vostochni Rookeries) on St. Paul Island, Alaska, and at the single breeding colony on Bogoslof Island, Alaska. Captures occurred during November, 2004 (St. Paul Island only); July, 2005; October-November, 2005; and July 2006. 20 seals at each island and during each capture period were weighed, measured, flipper tagged, and instrumented with satellite tags (platform transmitter terminals, or PTTs), for a total of 140 deployments. Seals were also instrumented with archival time-depth recorders (TDRs) during the July, 2005 (n = 20 TDRs at each island) and July, 2006 (n = 17 TDRs at each island) capture periods. Seals were recaptured, and the instruments recovered, at the end of the each summer. Data collection began on 11/06/2004 and ended on 10/19/2006; data represent 2 winter (fur seal migration) and 2 summer (fur seal lactation) study seasons. PTT (model: Kiwisat 101 and 202; Sirtrack Limited, Havelock North, New Zealand) transmissions were programmed to duty cycle at 4 hours on, 8 hours off during the winter study seasons and at 4 hours on, 4 hours off during the summer study seasons. TDRs (model Mk9; Wildlife Computers, Redmond, WA) sampled depth and temperature every 5 second. Data are composed of: fur seal capture and instrument deployment histories (1 spreadsheet); seal locations obtained from PTT deployments (4 spreadsheets, each containing all seal locations during a study season); TDR environmental sampling records (65 text files in 4 folders, each file representing a single TDR deployment and each folder representing the deployment island and summer study year for the included TDR files).

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.

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.

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.

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.

Adult male and female northern fur seals (Callorhinus ursinus) are sexually segregated in different regions of the North Pacific Ocean and Bering Sea during their winter migration. Explanations for this involve interplay between physiology, predator-prey dynamics, and ecosystem characteristics, however possible mechanisms lack empirical support. To investigate factors influencing the winter ecology of both sexes, we deployed five satellite-linked conductivity, temperature, and depth data loggers on adult males, and six satellite-linked depth data loggers and four satellite transmitters on adult females from St. Paul Island (Bering Sea, Alaska, USA) in October 2009. Males and females migrated to different regions of the North Pacific Ocean: males wintered in the Bering Sea and northern North Pacific Ocean, while females migrated to the Gulf of Alaska and California Current. Horizontal and vertical movement behaviors of both sexes were influenced by wind speed, season, light (sun and moon), and the ecosystem they occupied, although the expression of the behaviors differed between sexes. Male dive depths were aligned with the depth of the mixed layer during daylight periods and we suspect this was the case for females upon their arrival to the California Current. We suggest that females, because of their smaller size and physiological limitations, must avoid severe winters typical of the northern North Pacific Ocean and Bering Sea and migrate long distances to areas of more benign environmental conditions and where prey is shallower and more accessible. In contrast, males can better tolerate often extreme winter ocean conditions and exploit prey at depth because of their greater size and physiological capabilities. We believe these contrasting winter behaviors 1) are a consequence of evolutionary selection for large size in males, important to the acquisition and defense of territories against rivals during the breeding season, and 2) ease environmental/physiological constraints imposed on smaller females.

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.

Bearded seals (Erignathus barbatus) are one of the most important subsistence resources for the indigenous people of coastal northern and western Alaska, as well as key components of Arctic marine ecosystems. Yet, relatively little about their abundance, seasonal distribution, migrations, or foraging behaviors has been documented scientifically. Ice-associated seal populations may be negatively impacted by offshore oil and gas development as well as by climate change. Our ability to predict impacts, however, is limited by inadequate knowledge of seal population structure and foraging ecology. By working cooperatively with Alaska Native subsistence hunters we developed methods for live- capturing bearded seals in the Chukchi Sea using nets set in the shallow coastal waters where bearded seals were foraging. Capture efforts were based out of Kotzebue and various locations in the North Slope Borough from Wainwright to Barrow in June and July from 2009 to 2012. In all, 7 seals were caught (2 adults and 5 sub-adults; 4 males and three females; ranging in length and weight from 159 cm and 116 kg to 216 cm and 253 kg), all from Kotzebue Sound. Each seal was released with two different types of bio-logging devices: the SPOT5, attached to a rear flipper, provided information on the timing of hauling out and on the seal’s location for up to three years. The MK10, glued to the top of a seal’s head, provided the same information as well as data on the timing and depths of dives. MK10 deployments remained active up to ten months and were shed from the seal during the annual molt. The data files within this dataset represent the 'raw' data obtained from the Wildlife Computers data portal. Each deployment (unique tag id + animal id combination) is provided as a zipped archive. The root folder also includes additional documentation. The various files and detailed column descriptions are described in the 'Spreadsheet-File-Descriptions.pdf' which was downloaded from Wildlife Computers (https://wildlifecomputers.com/support/downloads/). The '00_kotzeb0912_get_data.Rmd' file is an RMarkdown file that provides code and documentation of the data retrieval process. The corresponding '00_kotzeb0912_get_data.hml' file is autogenerated from the RMarkdown file.

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 data set contains food habits determined from stomachs of northern fur seals collected from pelagic waters during 1981-1985. Prey items were identified using hard parts including bones, otoliths, and cephalopod beaks.