Now showing items 1-20 of 12946

    • The Level 2025-04

      Leigh, Nathan; Zenger, Adam; Leamer, Christena; Buness, Mardis; Lendrum, David; George, Greg; Kryman, Jakob; Reynolds, Kristin (University of Alaska Southeast, 2025-04-11)
    • The Level 2024-10

      Leigh, Nathan; Zenger, Adam; Lendrum, David; Bolaños, Mitzi; Cornejo, Elizabeth; Kryman, Jakob; Reynolds, Kristin; Trimble, Heather; George, Greg (2024-10-03)
    • The Level 2024-04

      Leamer, Christena; Leigh, Nathan; Reynolds, Kristin; Zenger, Adam; Trimble, Heather; Lendrum, David; Scharen, Andie; Buness, Mardis; Wade, Dana (University of Alaska Southeast, 2024-04-11)
    • The Level 2023-10

      Leigh, Nathan; Zenger, Adam; Buness, Mardis; Lendrum, David; Reynolds, Kristin; George, Greg (University of Alaska Southeast, 2023-10-16)
    • The Level 2021-09

      Leigh, Nathan; Lendrum, David; Zenger, Adam; George, Greg; Garcia, Dan; Mell, Ke; Kito II, Sam; Beck, Paul (University of Alaska Southeast, 2021-09-10)
    • The Level 2020-10

      Sand, Ryan; George, Greg; Zenger, Adam; Garcia, Dan; Leigh, Nathan; Lendrum, David; Mell, Ke; Kito II, Sam (University of Alaska Southeast, 2020-10-02)
    • The Level 2020-04

      Leigh, Nathan; Garcia, Dan; George, Greg; Zenger, Adam; Lendrum, David; Mell, Ke; Kito II, Sam (University of Alaska Southeast, 2020-04-30)
    • EVALUATING DRONE TECHNOLOGY TO IDENTIFY ICE CHANGES THAT CAN CAUSE ICE-ROAD HAZARDS

      Saiet, Eyal (2025-02-24)
      Ice roads in Alaska, a form that connects people during the winter months, enable the importing of critical goods and accessibility to medical services. These ice roads span 100 miles or more and are subject to spatial and temporal safety variability during the shoulder seasons and unseasonal warm events of above-freezing temperatures. In this work, we explore using an unmanned aircraft system (UAS) coupled with a ground penetrating radar (GPR) to inspect ice thickness safety and the presence of subsnow liquid overflow, common during winter. We compared our UAS-based GPR with ground-based GPR and nearby ice coring. We found the UAS-based GPR biased compared to the ice cores and the ground-based GPR. Nonetheless, when accounting for this bias, the UAS-based GPR had an RMSE of 5 cm for an ice thickness of 20 to 60 cm. More work is needed to understand the root cause of the UAS-based GPR for measuring ice thickness. The UAS-based GPR also effectively mapped subsnow liquid overflow by measuring the radar return amplitude, which is particularly strong when reflecting between the snow and water layers. Coupling UAS and GPR technology has great promise in conducting ice river safety assessments from a safe location. Still, more work must be done to understand the data’s bias.
    • Spawning stocks and juvenile summer habitat of rainbow trout and steelhead, Gulkana River, Alaska

      Stark, Thomas Christopher (1999-05)
      The Gulkana River supports the northernmost population of steelhead and rainbow trout Oncorhynchus mykiss in North America. The summer habitat of Gulkana River juvenile trout (i.e., steelhead and rainbow trout) was identified and described. Analysis of geomorphological features of stream reaches (stream entrenchment, bankfull width-to-depth ratio, sinuosity, channel material, and slope) in relation to differential use of habitat by juvenile trout indicated a strong preference for type C reaches (predominately riffle/run habitat) over type E reaches (predominately slow run habitat). A comparison of micro-habitats (riffle, run, pool, slow run) within those same reaches and distribution of juvenile trout indicated a preference for riffle and run habitat. Most type C reaches in the Mainstem were sparsely populated by juveniles throughout summer. The Middle Fork was devoid of juveniles in early summer. In mid- and late summer, coinciding with the arrival of spawning chinook O. tshawytscha and sockeye salmon O. nerka, most riffle/run reaches in the Middle Fork were occupied by juvenile trout. The steelhead spawning population has declined from an estimated 200-1,000 fish two decades ago to 20-50 fish during this study (1993-1995). Rainbow trout stocks are also apparently low. Monitoring of Copper River fisheries and Gulkana spawning populations and an investigation into other steelhead spawning populations in the Copper River basin are recommended
    • The Level 2019-10

      Garcia, Dan; Leigh, Nathan; Zenger, Adam; Lendrum, David (University of Alaska Southeast, 2019-10-03)
    • Alaska Earthquake Center Quarterly Technical Report October-December 2024

      McFarlin, Heather; Farrell, Alexandra; Grassi, Beth; Holtkamp, Stephen; Nadin, Elisabeth; Parcheta, Carolyn; Stabs, Angelica; West, Michael (Alaska Earthquake Center, 2025-04)
      This series of technical quarterly reports from the Alaska Earthquake Center (AEC) includes detailed summaries and updates on Alaska seismicity, the AEC seismic network and stations, fieldwork, our online presence, public outreach, and lists publications and presentations by AEC staff. Multiple AEC staff members contributed to this report.
    • Lake productivity indices as estimators of carrying capacity for burbot and northern pike in Interior Alaska

      Simpson, Thomas David (1998-12)
      Two Alaska sport fish species, burbot and northern pike, were used to test the ability to estimate carrying capacity of fishes based on biotic and abiotic indices of lake productivity. Understanding the quantitative relationships between the potential fish productivity of freshwater lakes and physical, biological, or chemical characteristics could provide models sufficient for calculating a timely prediction of carrying capacity to evaluate the population status. This would provide a technique for allocating limited resources for fishery stock assessment as an aide in resource management of sport fisheries. The lakes covered in the study lie in an area spanning West 151°--142°/North 64°30ʹ--61°52ʹ. They are Fielding Lake, George Lake, Glacier Lake, Harding Lake, Hudson Lake, Jatahmund Lake, Lake Louise, Landlocked Tangle Lake, Moose Lake, Paxson Lake, Sevenmile Lake, T Lake, Tolsona Lake, Volkmar Lake, and West Twin Lake.
    • Indigenous engagement with the Alexander Archipelago Wolf: Cultural context and traditional ecological knowledge

      Langdon, Stephen J.; Brooks, Jeffrey J.; Ackerman, Tim; Anderstrom, Devlin Shaag̱ aw Éesh; Atkinson, Eldon C.; Douville, Michael Gitwaayne; George, Thomas Allen; Hotch, Stanley Yeilwú; Jackson, Michael Kauish; Jackson, Nathan; et al. (Sealaska Heritage Institute, 2023-12-31)
      The U.S. Fish and Wildlife Service in Alaska conducted a Species Status Assessment in response to a petition to list the Alexander Archipelago wolf under the Endangered Species Act. This federal undertaking could not be adequately prepared without including the voices of the Indigenous People who have a deep connection with the subspecies. The Indigenous knowledge presented in this report is the cultural and intellectual property of those who have shared it. The purpose of the report is to communicate the knowledge shared with us to the U.S. Fish and Wildlife Service to help inform the Species Status Assessment and future tribal consultations, wildlife research, and management. Due to a constrained regulatory timeline, we employed rapid appraisal research to expeditiously develop a preliminary understanding of Indigenous People’s ecological knowledge of wolves. We applied the social scientific methods of qualitative ethnography and inductive coding from grounded theory for text analysis. We conducted archival research and literature reviews on the cultural significance of wolves in Tlingit society and social organization to supplement in-depth conversations with traditional knowledge holders who are local wolf experts. The study was informed by two tribal consultations.
    • American Museum of Natural History Educator's Guide: Northwest Coast Hall

      Ramos, Judith Dax̱ootsú; Smith Wilson, Laurel Xsim Ganaa’w (American Museum of Natural History, 2024)
      Welcome to the Northwest Coast Hall. Reopened in 2022, it is the result of an intensive five-year collaboration between the Museum and ten advisors from the Indigenous cultural groups featured in the hall. This revitalized hall celebrates Indigenous worldview, artistry, cultural persistence, and the distinct practices and histories of the individual Nations along the Northwest Coast.
    • Seasonal habitat relationships of adult female deer on Kodiak Island, Alaska

      Selinger, Jeffrey S. (1995-12)
      Movements of adult female deer (Odocoileus hemionus sitkensis) were monitored using radio-collars (n = 21) in a region lacking old-growth conifer forest on Kodiak Island, Alaska, from 17 July 1990 to 8 July 1991. Mean distance between seasonal ranges for 7 deer that migrated from the study area during winter was 22 km (SD = 10.2 km), whereas < 5 km separated seasonal ranges of 14 deer that remained in the study area throughout the year. Mean movement date to winter range was 30 October (SD = 38 days), and to summer range, 29 May (SD = 18 days). Overall habitat use differed significantly (P < 0.001) between seasons. Habitats used more than available (P ≤ 0.01) were tall shrub closed in summer and tall shrub open in winter. Using the 95% adaptive kernel method (Worton 1989), mean summer home range (454 ha, n = 11, range 134 - 819 ha, SD = 227 ha) was larger (P < 0.001)than the mean winter home range (107 ha, n = 9, range 67-217 ha, SD = 56 ha).
    • Indigenous use and conservation of harbor seals (Phoca vitulina) at Yakutat, Alaska since the sixteenth century

      Crowell, Aron L.; Ramos, Judith Dax̱ootsú; Etnier, Michael A. (Frontiers Media S.A., 2024-11-13)
      Sustainable Indigenous resource use reflects balance between animal populations and levels of human consumption, influenced by natural cycles of faunal abundance, community size and subsistence needs, procurement technologies, and the requirements of trade or commodity production. Sustainability is “epiphenomenal” when animal populations are preserved, and community needs met, without deliberate measures to prevent overharvesting. Alternatively, Indigenous conservation—cultural practices that moderate use of a resource to prevent its depletion—may play a determinative role. In this study from the Tlingit community of Yakutat, Alaska in the Northwest Coast cultural region, we interweave Indigenous and scientific perspectives to trace the use and conservation of harbor seals (Phoca vitulina) from before Western contact through the Russian and American colonial periods to the present. Harbor seals, which concentrate in large numbers at a summer ice floe rookery near Hubbard Glacier, are the community's most important subsistence food and a key to its culture and history. The Smithsonian Institution and Yakutat Tlingit Tribe undertook collaborative research in historical ecology and archaeology in 2011–2014 including oral interviews with elders and subsistence providers, excavations at sealing sites, archaeofaunal analysis, historical and archival research, and consideration of climate cycles and biological regime shifts that influence the harbor seal population in the Gulf of Alaska. We compare technologies and hunting practices before and after Western contact, estimate harvest levels in different periods, and evaluate the effectiveness of traditional conservation practices that included hunting quotas enforced by clan leaders and the seasonal delay of hunting with firearms to prevent abandonment of the rookery by the seal herd.
    • Downstream passage performance of silver eel at an angled rack: Effects of behavior and morphology

      Motyka, Roman; Watz, Johan; Aldvén, David; Carlsson, Niclas; Eissenhauer, Felix; Harbicht, Andrew; Karathanou, Eirini; Knieps, Tobias; Lind, Lovisa; Calles, Olle (Springer Nature, 2024-04-13)
      The European eel is critically endangered due to heavy impact of anthropogenic factors, such as habitat fragmentation, overexploitation and climate change. During downstream migration, silver eels may encounter hydropower plants, which often result in delay or mortality from impingement on trash-racks or turbine passage. These problems can be mitigated with downstream passage solutions, such as angled racks that guide downstream-migrating eels to safe passage routes. The importance of bar spacing and phenotypic diversity for passage performance is, however, largely unknown. In this study, we investigated how morphological parameters (body mass, eye and fin indices) and behavioral score (open field test) influenced passage rate at an experimental intake equipped with a bypass and angled racks with either 15 or 30 mm bar spacing. Both racks were efficient in guiding eels into a bypass. There was a strong positive effect of body mass and a weak positive effect of open field test score on passage rate. Other factors such as eye and fin indices played a minor role. These results demonstrate the performance of angled racks with bypasses and form a useful starting point for further research regarding the relationships between individual variation in behavior, morphology and passage solutions for silver eels.
    • Optimizing seaweed biomass production ‑ A two kelp solution

      Stekoll, Michael; Pryor, Alf; Meyer, Alexandra; Kite-Powell, Hauke L.; Bailey, David; Berbery, Kendall; Goudey, Clifford A.; Lindell, Scott; Roberson, Loretta; Yarish, Charles (Springer Nature, 2024-07-02)
      Interest in farming kelps has grown beyond using kelp for food, feed or biofuels. There is considerable interest in generating biomass from seaweed for use in bioplastics and other products that would substitute for petroleum-derived products. For these uses to be viable, large amounts of biomass are needed. Very large kelp farms can be expensive to build and maintain, leading to the need to optimize the biomass per unit area. Although close spacing of growlines can lead to poor growth, a viable approach may be to grow two species of kelps together: one that hangs down and one that is buoyant, growing up. This system would increase the spacing in three dimensions. In Alaska, Saccharina latissima is commonly grown hanging down from longlines. One of the buoyant Alaskan kelps is Nereocystis luetkeana. Because there are commercial uses for wild-harvested Nereocystis in Alaska, we undertook a preliminary trial in Kodiak, Alaska, that grew both Saccharina and Nereocystis in the same longline array. Closely spaced lines were seeded the first week of February 2023 and set at 3 m below the surface. The arrays were harvested in late June 2023. Total yields were greatest on the combined arrays, followed by the Nereocystis only and Saccharina only arrays. Despite having 45% fewer grow-lines, the total yield of the Nereocystis on the combined arrays was statistically similar to the Nereocystis only arrays. These results may have significance for large scale macroalgal production.
    • Plant architecture and forage selection by moose

      Mallek, Edward Joseph II (1999-08)
      The effects of plant architecture on browse selection and the extent of use of Salix alaxensis and Salix plantifolia by moose foraging in winter in Interior Alaska were studied during 1997 and 1998. Three sampling techniques were employed to estimate forage availability and utilization. Sampling forage availability prior to use (in autumn) provided the best estimates of forage use in spring. In Salix plantifolia, selection of current annual growth (CAG) twigs was significantly related to basal diameter of CAG, diameter of nearest neighbor, distance to nearest neighbor, and number of leaders per cluster. In contrast, CAG selection in Salix alaxensis was related only to basal diameter. The proportion of CAG biomass removed from stems of either species was not related to any measured plant architecture variables. Because plant architecture affects browse use by moose, it is an important factor in determining food availability, and thereby in assessing moose habitat