Descriptions of the full Weekly Findings and links to more information.
Return to Weekly Findings
Increased Pathogen Exposure of Polar Bears in the Chukchi Sea
Pathogen exposure in wildlife is important for identifying factors that can affect species health and for monitoring the potential for species to serve as vectors in transmitting disease to humans, particularly for harvested species such as polar bears. A study examined changes in pathogen exposure via antibodies in serum and fecal parasites across three decades for polar bears that occur in the Chukchi Sea. Prevalence of serum antibodies, indicative of exposure, increased between 1987-1994 and 2008-2017 for five: Toxoplasma gondii, Neospora caninum, Francisella tularensis, Brucella abortus/suis, and canine distemper virus. Exposure was related to diet for several pathogens suggesting exposure in the food web. Elevated white blood cell counts in association with antibodies for some pathogens suggest a possible immune response of polar bears. The study was published in PLoS ONE and is available at: https://doi.org/10.1371/journal.pone.0310973. Learn More>>
Contact: Karyn Rode, Research Wildlife Biologist
Modeling, Mapping, and Measuring the Risk of Invasive Freshwater Species Across Alaska
Prevention and preparedness to identify and control introductions are key to effective invasive species management. This report describes a collaborative effort to identify and prioritize aquatic invasive species known to be invasive in the contiguous United States, evaluate current and future habitat suitability for aquatic invasive species in Alaska, and assess potential for aquatic invasive species to be transported to habitats across Alaska. The report is available at: https://accs.uaa.alaska.edu/publications. Learn More>>
Contact: Michael Carey, Research Fish Biologist
Why the Tallest Mountain in North America is so Tall?
A new paper assesses the growth of anomalously high relief on Denali, located in the Alaska Range, Alaska, and the tallest mountain in North America. Denali lies inside a 19° restraining bend in the active Denali fault system that is moving at about 7 mm/yr, providing a tectonic and structural driver for ongoing rock uplift. High relief around Denali is also due, in part, to its granitic rock type and low fracture density relative to adjacent metasediments. Here we show that unique climatic conditions at high elevations also contribute to the growth of relief. Meteorological data at 5 sites show temperatures rarely exceed freezing above 13,000 feet elevation, indicating that frost weathering currently plays a diminished role in erosion at high elevations. These results highlight the combined influence of rock type, glacial erosion, and permanent sub-zero temperatures on erosion rates. The paper is available in Earth and Planetary Science Letters at: https://doi.org/10.1016/j.epsl.2024.118999.
Contact: Douglas Kreiner, Associate Center Director for Geology
Assessing the Population Consequences of Disturbance and Climate Change for the Pacific Walrus
As the Arctic becomes increasingly ice-free, walruses spend more time at coastal, as opposed to ice-based, haulouts, from which they must expend more energy to reach foraging areas and where they experience an elevated risk of mortality. Sea ice loss is also increasing the anthropogenic footprint in the Arctic, allowing new fisheries, shipping routes, and energy exploration, which creates additional disturbance for walruses. This study developed and applied a modeling framework that incorporated global sea ice model projections and varying degrees of anthropogenic disturbance to assess potential future changes to the Pacific walrus population, a critical subsistence resource for indigenous communities along the Bering and Chukchi Sea coasts in Alaska and Russia. All scenarios indicated a decline in Pacific walrus population vital rates by the end of the 21st century, but our results demonstrated that the intensity of that decline could be mitigated by global efforts to reduce carbon emissions, along with local management and conservation efforts to protect important coastal haulouts and foraging grounds. The publication is available at: https://doi.org/10.3354/meps14635. Learn More>>
Contact: Joe Eisaguirre, Research Wildlife Biologist
Understanding Sea Otter Population Change in Southeast Alaska
Since sea otters were reintroduced to Southeast Alaska in the late 1960s, several efforts over the years have contributed to our present understanding of the population. Many of these efforts used different methods that occasionally led to different estimates of sea otter population abundance in the region. Given recent survey efforts and advances in statistical methods, this fact sheet summarizes how our understanding of the sea otter population in Southeast Alaska has changed through time both as new data were collected, and new methods developed. The fact sheet also highlights some ongoing research and next steps by USGS and collaborators to better understand the population ecology of sea otters and inform management in the region. The fact sheet is available at: https://doi.org/10.3133/fs20243007. Learn More>>
Contact: Joe Eisaguirre, Research Wildlife Biologist
Descriptions of the full Weekly Findings and links to more information.
Return to Weekly Findings
Increased Pathogen Exposure of Polar Bears in the Chukchi Sea
Pathogen exposure in wildlife is important for identifying factors that can affect species health and for monitoring the potential for species to serve as vectors in transmitting disease to humans, particularly for harvested species such as polar bears. A study examined changes in pathogen exposure via antibodies in serum and fecal parasites across three decades for polar bears that occur in the Chukchi Sea. Prevalence of serum antibodies, indicative of exposure, increased between 1987-1994 and 2008-2017 for five: Toxoplasma gondii, Neospora caninum, Francisella tularensis, Brucella abortus/suis, and canine distemper virus. Exposure was related to diet for several pathogens suggesting exposure in the food web. Elevated white blood cell counts in association with antibodies for some pathogens suggest a possible immune response of polar bears. The study was published in PLoS ONE and is available at: https://doi.org/10.1371/journal.pone.0310973. Learn More>>
Contact: Karyn Rode, Research Wildlife Biologist
Modeling, Mapping, and Measuring the Risk of Invasive Freshwater Species Across Alaska
Prevention and preparedness to identify and control introductions are key to effective invasive species management. This report describes a collaborative effort to identify and prioritize aquatic invasive species known to be invasive in the contiguous United States, evaluate current and future habitat suitability for aquatic invasive species in Alaska, and assess potential for aquatic invasive species to be transported to habitats across Alaska. The report is available at: https://accs.uaa.alaska.edu/publications. Learn More>>
Contact: Michael Carey, Research Fish Biologist
Why the Tallest Mountain in North America is so Tall?
A new paper assesses the growth of anomalously high relief on Denali, located in the Alaska Range, Alaska, and the tallest mountain in North America. Denali lies inside a 19° restraining bend in the active Denali fault system that is moving at about 7 mm/yr, providing a tectonic and structural driver for ongoing rock uplift. High relief around Denali is also due, in part, to its granitic rock type and low fracture density relative to adjacent metasediments. Here we show that unique climatic conditions at high elevations also contribute to the growth of relief. Meteorological data at 5 sites show temperatures rarely exceed freezing above 13,000 feet elevation, indicating that frost weathering currently plays a diminished role in erosion at high elevations. These results highlight the combined influence of rock type, glacial erosion, and permanent sub-zero temperatures on erosion rates. The paper is available in Earth and Planetary Science Letters at: https://doi.org/10.1016/j.epsl.2024.118999.
Contact: Douglas Kreiner, Associate Center Director for Geology
Assessing the Population Consequences of Disturbance and Climate Change for the Pacific Walrus
As the Arctic becomes increasingly ice-free, walruses spend more time at coastal, as opposed to ice-based, haulouts, from which they must expend more energy to reach foraging areas and where they experience an elevated risk of mortality. Sea ice loss is also increasing the anthropogenic footprint in the Arctic, allowing new fisheries, shipping routes, and energy exploration, which creates additional disturbance for walruses. This study developed and applied a modeling framework that incorporated global sea ice model projections and varying degrees of anthropogenic disturbance to assess potential future changes to the Pacific walrus population, a critical subsistence resource for indigenous communities along the Bering and Chukchi Sea coasts in Alaska and Russia. All scenarios indicated a decline in Pacific walrus population vital rates by the end of the 21st century, but our results demonstrated that the intensity of that decline could be mitigated by global efforts to reduce carbon emissions, along with local management and conservation efforts to protect important coastal haulouts and foraging grounds. The publication is available at: https://doi.org/10.3354/meps14635. Learn More>>
Contact: Joe Eisaguirre, Research Wildlife Biologist
Understanding Sea Otter Population Change in Southeast Alaska
Since sea otters were reintroduced to Southeast Alaska in the late 1960s, several efforts over the years have contributed to our present understanding of the population. Many of these efforts used different methods that occasionally led to different estimates of sea otter population abundance in the region. Given recent survey efforts and advances in statistical methods, this fact sheet summarizes how our understanding of the sea otter population in Southeast Alaska has changed through time both as new data were collected, and new methods developed. The fact sheet also highlights some ongoing research and next steps by USGS and collaborators to better understand the population ecology of sea otters and inform management in the region. The fact sheet is available at: https://doi.org/10.3133/fs20243007. Learn More>>
Contact: Joe Eisaguirre, Research Wildlife Biologist