Kristin Simac
Logistical support for Polar Bear Research Group
Coordination of sample collections for Alaska Marine Mammal Tissue and Archival Program
Education and Certifications
M.S. 2001 Alaska Pacific University, Anchorage, AK Environmental Science
B.S. 1984 Willamette University, Salem, OR Biology
Science and Products
Health and Energetics of Polar Bears
The warming climate has the potential to drive significant changes in the health and energetics of Arctic fauna, particularly those dependent on sea ice habitats like polar bears. An animal’s health and energetic state reflects the interaction between its behavioral choices and the environment. Because of this, measuring changes in health and energetics has potential for revealing important...
Polar Bear Research
Polar bears ( Ursus maritimus ) are one of 4 marine mammal species managed by the U.S. Department of Interior. The USGS Alaska Science Center leads long–term research on polar bears to inform local, state, national and international policy makers regarding conservation of the species and its habitat. Our studies, ongoing since 1985, are focused on population dynamics, health and energetics...
Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017
his dataset consists of one table with estimated locations of adult female polar bears during July-November 1985-2017, used for quantifying changes in summer land use over time. Locations were estimated with a Continuous Time-Correlated Random Walk (CTCRW) model fit to satellite tracking from radio-collared adult female polar bears. All bears included in this data set were captured and instrumente
Serum Urea and Creatinine Levels of Spring-Caught Polar Bears (Ursus maritimus) in the Southern Beaufort and Chukchi Seas
These data are serum urea nitrogen and creatinine levels for polar bears captured in the southern Beaufort Sea 1983-2016 and the Chukchi Sea 1987-1993 and 2008-2017. The dataset includes relevant information about the bears that were captured including the latitude and longitude of their capture location, capture date, age class and sex, the age and number of cubs accompanying an adult female, and
Multistate capture and search data from the southern Beaufort Sea polar bear population in Alaska, 2001-2016
This data release contains two tables of information on polar bear distributions in the southern Beaufort Sea during spring, from 2001 to 2016. One table provides location (classified into 5 broad regions) of individual bears during the spring. The other table presents the aerial search effort by year and area.
Filter Total Items: 21
Long-term variation in polar bear body condition and maternal investment relative to a changing environment
In the Arctic, warming air and ocean temperatures have resulted in substantial changes to sea ice, which is primary habitat for polar bears (Ursus maritimus). Reductions in extent, duration, and thickness have altered sea ice dynamics, which influences the ability of polar bears to reliably access marine mammal prey. Because nutritional condition is closely linked to population vital rates, a prog
Authors
Todd C. Atwood, Karyn D. Rode, David C. Douglas, Kristin S. Simac, Anthony Pagano, Jeffrey F. Bromaghin
Survival and abundance of polar bears in Alaska’s Beaufort Sea, 2001–2016
The Arctic Ocean is undergoing rapid transformation toward a seasonally ice-free ecosystem. As ice-adapted apex predators, polar bears (Ursus maritimus) are challenged to cope with ongoing habitat degradation and changes in their prey base driven by food-web response to climate warming. Knowledge of polar bear response to environmental change is necessary to understand ecosystem dynamics and infor
Authors
Jeffrey F. Bromaghin, David C. Douglas, George M. Durner, Kristin S. Simac, Todd C. Atwood
Analyses on subpopulation abundance and annual number of maternal dens for the U.S. Fish and Wildlife Service on polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska
The long-term persistence of polar bears (Ursus maritimus) is threatened by sea-ice loss due to climate change, which is concurrently providing an opportunity in the Arctic for increased anthropogenic activities including natural resource extraction. Mitigating the risk of those activities, which can adversely affect the population dynamics of the southern Beaufort Sea (SBS) subpopulation, is an e
Authors
Todd C. Atwood, Jeffrey F. Bromaghin, Vijay P. Patil, George M. Durner, David C. Douglas, Kristin S. Simac
Identifying reliable indicators of fitness in polar bears
Animal structural body size and condition are often measured to evaluate individual health, identify responses to environmental change and food availability, and relate food availability to effects on reproduction and survival. A variety of condition metrics have been developed but relationships between these metrics and vital rates are rarely validated. Identifying an optimal approach to estimate
Authors
Karyn D. Rode, Todd C. Atwood, Gregory Thiemann, Michelle St. Martin, Ryan H. Wilson, George M. Durner, Eric V. Regehr, Sandra L. Talbot, Kevin Sage, Anthony M. Pagano, Kristin S. Simac
Reference intervals for blood-based biochemical analytes of southern Beaufort Sea polar bears
Accurate reference intervals (RI) for commonly measured blood-based analytes are essential for health monitoring programs. Baseline values for a panel of analytes can be used to monitor physiologic and pathophysiologic processes such as organ function, electrolyte balance, and protein catabolism. Our reference population includes 651 serum samples from polar bears (Ursus maritimus) from the south
Authors
Tricia Fry, Kristen R. Friedrichs, Todd C. Atwood, Colleen G. Duncan, Kristin S. Simac, Tony Goldberg
Human-polar bear interactions in a changing Arctic: Existing and emerging concerns
The behavior and sociality of polar bears (Ursus maritimus) have been shaped by evolved preferences for sea ice habitat and preying on marine mammals. However, human behavior is causing changes to the Arctic marine ecosystem through the influence of greenhouse gas emissions that drive long-term change in ecosystem processes and via the presence of in situ stressors associated with increasing human
Authors
Todd C. Atwood, Kristin S. Simac, Stewart Breck, Geoff York, James Wilder
Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity
The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume
Authors
Karyn D. Rode, Ryan H. Wilson, David C. Douglas, Vanessa L Muhlenbruch, Todd C. Atwood, Eric V. Regehr, Evan Richardson, Nicholas Pilfold, Andrew E. Derocher, George M. Durner, Ian Stirling, Steven C. Amstrup, Michelle St. Martin, Anthony M. Pagano, Kristin S. Simac
An experimental investigation of chemical communication in the polar bear
The polar bear (Ursus maritimus), with its wide-ranging movements, solitary existence and seasonal reproduction, is expected to favor chemosignaling over other communication modalities. However, the topography of its Arctic sea ice habitat is generally lacking in stationary vertical substrates routinely used for targeted scent marking in other bears. These environmental constraints may have shaped
Authors
Megan A. Owen, Ronald R. Swaisgood, C. Slocomb, Steven C. Amstrup, George M. Durner, Kristin S. Simac, Allan P. Pessier
Effects of capturing and collaring on polar bears: findings from long-term research on the southern Beaufort Sea population
Context: The potential for research methods to affect wildlife is an increasing concern among both scientists and the public. This topic has a particular urgency for polar bears because additional research is needed to monitor and understand population responses to rapid loss of sea ice habitat.Aims: This study used data collected from polar bears sampled in the Alaska portion of the southern Beau
Authors
Karyn D. Rode, Anthony M. Pagano, Jeffrey F. Bromaghin, Todd C. Atwood, George M. Durner, Kristin S. Simac, Steven C. Amstrup
Mapping polar bear maternal denning habitat in the National Petroleum Reserve -- Alaska with an IfSAR digital terrain model
The National Petroleum Reserve–Alaska (NPR-A) in northeastern Alaska provides winter maternal denning habitat for polar bears (Ursus maritimus) and also has high potential for recoverable hydrocarbons. Denning polar bears exposed to human activities may abandon their dens before their young are able to survive the severity of Arctic winter weather. To ensure that wintertime petroleum activities do
Authors
George M. Durner, Kristin S. Simac, Steven C. Amstrup
Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water
Polar bears (Ursus maritimus Phipps, 1774) depend on sea ice for catching marine mammal prey. Recent sea-ice declines have been linked to reductions in body condition, survival, and population size. Reduced foraging opportunity is hypothesized to be the primary cause of sea-ice-linked declines, but the costs of travel through a deteriorated sea-ice environment also may be a factor. We used movemen
Authors
Anthony M. Pagano, George M. Durner, Kristin S. Simac, G.S. York, Steven C. Amstrup
Development of a murre (Uria spp.) egg control material
The Seabird Tissue Archival and Monitoring Project (STAMP) is a collaborative Alaska-wide effort by the US Fish and Wildlife Service's Alaska Maritime National Wildlife Refuge (USFWS/AMNWR), the US Geological Survey's Biological Resources Division (USGS/BRD), the Bureau of Indian Affairs Alaska Region Subsistence Branch (BIA/ARSB), and the National Institute of Standards and Technology (NIST) to m
Authors
Stacy S. Vander Pol, M.B. Ellisor, Rebecca S. Pugh, P.R. Becker, D.L. Poster, M.M. Schantz, S.D. Leigh, B.J. Wakeford, David G. Roseneau, Kristin S. Simac
Science and Products
Health and Energetics of Polar Bears
The warming climate has the potential to drive significant changes in the health and energetics of Arctic fauna, particularly those dependent on sea ice habitats like polar bears. An animal’s health and energetic state reflects the interaction between its behavioral choices and the environment. Because of this, measuring changes in health and energetics has potential for revealing important...
Polar Bear Research
Polar bears ( Ursus maritimus ) are one of 4 marine mammal species managed by the U.S. Department of Interior. The USGS Alaska Science Center leads long–term research on polar bears to inform local, state, national and international policy makers regarding conservation of the species and its habitat. Our studies, ongoing since 1985, are focused on population dynamics, health and energetics...
Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017
his dataset consists of one table with estimated locations of adult female polar bears during July-November 1985-2017, used for quantifying changes in summer land use over time. Locations were estimated with a Continuous Time-Correlated Random Walk (CTCRW) model fit to satellite tracking from radio-collared adult female polar bears. All bears included in this data set were captured and instrumente
Serum Urea and Creatinine Levels of Spring-Caught Polar Bears (Ursus maritimus) in the Southern Beaufort and Chukchi Seas
These data are serum urea nitrogen and creatinine levels for polar bears captured in the southern Beaufort Sea 1983-2016 and the Chukchi Sea 1987-1993 and 2008-2017. The dataset includes relevant information about the bears that were captured including the latitude and longitude of their capture location, capture date, age class and sex, the age and number of cubs accompanying an adult female, and
Multistate capture and search data from the southern Beaufort Sea polar bear population in Alaska, 2001-2016
This data release contains two tables of information on polar bear distributions in the southern Beaufort Sea during spring, from 2001 to 2016. One table provides location (classified into 5 broad regions) of individual bears during the spring. The other table presents the aerial search effort by year and area.
Filter Total Items: 21
Long-term variation in polar bear body condition and maternal investment relative to a changing environment
In the Arctic, warming air and ocean temperatures have resulted in substantial changes to sea ice, which is primary habitat for polar bears (Ursus maritimus). Reductions in extent, duration, and thickness have altered sea ice dynamics, which influences the ability of polar bears to reliably access marine mammal prey. Because nutritional condition is closely linked to population vital rates, a prog
Authors
Todd C. Atwood, Karyn D. Rode, David C. Douglas, Kristin S. Simac, Anthony Pagano, Jeffrey F. Bromaghin
Survival and abundance of polar bears in Alaska’s Beaufort Sea, 2001–2016
The Arctic Ocean is undergoing rapid transformation toward a seasonally ice-free ecosystem. As ice-adapted apex predators, polar bears (Ursus maritimus) are challenged to cope with ongoing habitat degradation and changes in their prey base driven by food-web response to climate warming. Knowledge of polar bear response to environmental change is necessary to understand ecosystem dynamics and infor
Authors
Jeffrey F. Bromaghin, David C. Douglas, George M. Durner, Kristin S. Simac, Todd C. Atwood
Analyses on subpopulation abundance and annual number of maternal dens for the U.S. Fish and Wildlife Service on polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska
The long-term persistence of polar bears (Ursus maritimus) is threatened by sea-ice loss due to climate change, which is concurrently providing an opportunity in the Arctic for increased anthropogenic activities including natural resource extraction. Mitigating the risk of those activities, which can adversely affect the population dynamics of the southern Beaufort Sea (SBS) subpopulation, is an e
Authors
Todd C. Atwood, Jeffrey F. Bromaghin, Vijay P. Patil, George M. Durner, David C. Douglas, Kristin S. Simac
Identifying reliable indicators of fitness in polar bears
Animal structural body size and condition are often measured to evaluate individual health, identify responses to environmental change and food availability, and relate food availability to effects on reproduction and survival. A variety of condition metrics have been developed but relationships between these metrics and vital rates are rarely validated. Identifying an optimal approach to estimate
Authors
Karyn D. Rode, Todd C. Atwood, Gregory Thiemann, Michelle St. Martin, Ryan H. Wilson, George M. Durner, Eric V. Regehr, Sandra L. Talbot, Kevin Sage, Anthony M. Pagano, Kristin S. Simac
Reference intervals for blood-based biochemical analytes of southern Beaufort Sea polar bears
Accurate reference intervals (RI) for commonly measured blood-based analytes are essential for health monitoring programs. Baseline values for a panel of analytes can be used to monitor physiologic and pathophysiologic processes such as organ function, electrolyte balance, and protein catabolism. Our reference population includes 651 serum samples from polar bears (Ursus maritimus) from the south
Authors
Tricia Fry, Kristen R. Friedrichs, Todd C. Atwood, Colleen G. Duncan, Kristin S. Simac, Tony Goldberg
Human-polar bear interactions in a changing Arctic: Existing and emerging concerns
The behavior and sociality of polar bears (Ursus maritimus) have been shaped by evolved preferences for sea ice habitat and preying on marine mammals. However, human behavior is causing changes to the Arctic marine ecosystem through the influence of greenhouse gas emissions that drive long-term change in ecosystem processes and via the presence of in situ stressors associated with increasing human
Authors
Todd C. Atwood, Kristin S. Simac, Stewart Breck, Geoff York, James Wilder
Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity
The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume
Authors
Karyn D. Rode, Ryan H. Wilson, David C. Douglas, Vanessa L Muhlenbruch, Todd C. Atwood, Eric V. Regehr, Evan Richardson, Nicholas Pilfold, Andrew E. Derocher, George M. Durner, Ian Stirling, Steven C. Amstrup, Michelle St. Martin, Anthony M. Pagano, Kristin S. Simac
An experimental investigation of chemical communication in the polar bear
The polar bear (Ursus maritimus), with its wide-ranging movements, solitary existence and seasonal reproduction, is expected to favor chemosignaling over other communication modalities. However, the topography of its Arctic sea ice habitat is generally lacking in stationary vertical substrates routinely used for targeted scent marking in other bears. These environmental constraints may have shaped
Authors
Megan A. Owen, Ronald R. Swaisgood, C. Slocomb, Steven C. Amstrup, George M. Durner, Kristin S. Simac, Allan P. Pessier
Effects of capturing and collaring on polar bears: findings from long-term research on the southern Beaufort Sea population
Context: The potential for research methods to affect wildlife is an increasing concern among both scientists and the public. This topic has a particular urgency for polar bears because additional research is needed to monitor and understand population responses to rapid loss of sea ice habitat.Aims: This study used data collected from polar bears sampled in the Alaska portion of the southern Beau
Authors
Karyn D. Rode, Anthony M. Pagano, Jeffrey F. Bromaghin, Todd C. Atwood, George M. Durner, Kristin S. Simac, Steven C. Amstrup
Mapping polar bear maternal denning habitat in the National Petroleum Reserve -- Alaska with an IfSAR digital terrain model
The National Petroleum Reserve–Alaska (NPR-A) in northeastern Alaska provides winter maternal denning habitat for polar bears (Ursus maritimus) and also has high potential for recoverable hydrocarbons. Denning polar bears exposed to human activities may abandon their dens before their young are able to survive the severity of Arctic winter weather. To ensure that wintertime petroleum activities do
Authors
George M. Durner, Kristin S. Simac, Steven C. Amstrup
Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water
Polar bears (Ursus maritimus Phipps, 1774) depend on sea ice for catching marine mammal prey. Recent sea-ice declines have been linked to reductions in body condition, survival, and population size. Reduced foraging opportunity is hypothesized to be the primary cause of sea-ice-linked declines, but the costs of travel through a deteriorated sea-ice environment also may be a factor. We used movemen
Authors
Anthony M. Pagano, George M. Durner, Kristin S. Simac, G.S. York, Steven C. Amstrup
Development of a murre (Uria spp.) egg control material
The Seabird Tissue Archival and Monitoring Project (STAMP) is a collaborative Alaska-wide effort by the US Fish and Wildlife Service's Alaska Maritime National Wildlife Refuge (USFWS/AMNWR), the US Geological Survey's Biological Resources Division (USGS/BRD), the Bureau of Indian Affairs Alaska Region Subsistence Branch (BIA/ARSB), and the National Institute of Standards and Technology (NIST) to m
Authors
Stacy S. Vander Pol, M.B. Ellisor, Rebecca S. Pugh, P.R. Becker, D.L. Poster, M.M. Schantz, S.D. Leigh, B.J. Wakeford, David G. Roseneau, Kristin S. Simac