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Jeffrey Bromaghin, Ph.D. (Former Employee)

Science and Products

Polar bear mother and two cubs on the Beaufort Sea ice.

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...
By
Ecosystems Mission Area, Land Management Research Program, Species Management Research Program, Alaska Science Center
Polar Bear Research

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...
Learn More
Sampling a stream in the mist in the Akilik River drainage

Ecosystems Analytics

Ecosystems Analytics is a group of quantitative biologists and research statisticians with a diverse range of expertise and experience (summarized below). We collaborate with internal and external partners to answer challenging ecological questions that are a high priority of the U.S. Geological Survey Alaska Science Center, sister agencies within the Department of the Interior (DOI), and various...
By
Ecosystems Mission Area, Alaska Science Center
Ecosystems Analytics

Ecosystems Analytics

Ecosystems Analytics is a group of quantitative biologists and research statisticians with a diverse range of expertise and experience (summarized below). We collaborate with internal and external partners to answer challenging ecological questions that are a high priority of the U.S. Geological Survey Alaska Science Center, sister agencies within the Department of the Interior (DOI), and various...
Learn More
Polar bear appears to walk on top of rippled gray water. Just behind it are very large breaking waves below a gray-blue sky.

Polar Bear Population Dynamics

Information on the status and trends of polar bear populations are needed to inform management of polar bears under US laws and international agreements. The USGS maintains a long-term research program focused on the population dynamics of the southern Beaufort Sea polar bear population. In addition, the USGS collaborates with the US Fish and Wildlife Service in population studies in the Chukchi...
By
Species Management Research Program, Alaska Science Center
Polar Bear Population Dynamics

Polar Bear Population Dynamics

Information on the status and trends of polar bear populations are needed to inform management of polar bears under US laws and international agreements. The USGS maintains a long-term research program focused on the population dynamics of the southern Beaufort Sea polar bear population. In addition, the USGS collaborates with the US Fish and Wildlife Service in population studies in the Chukchi...
Learn More

Southern Beaufort Sea Polar Bear Fatty Acid Data, Spring Samples 2004-2016 Southern Beaufort Sea Polar Bear Fatty Acid Data, Spring Samples 2004-2016

These data consist of the fatty acid composition (percent of mass) of adipose tissue samples from polar bears in Alaska's southern Beaufort Sea. Fat biopsy samples were collected from polar bears that were either captured or biopsy darted along the north coast of Alaska or on offshore ice during March, April, or May from 2004 to 2016. The data also include an identification code unique...
By
Alaska Science Center

Diet Composition of Southern Beaufort Sea Polar Bears Sampled in Spring from 2004 to 2016 Estimated with Quantitative Fatty Acid Signature Analysis Diet Composition of Southern Beaufort Sea Polar Bears Sampled in Spring from 2004 to 2016 Estimated with Quantitative Fatty Acid Signature Analysis

These data are estimates of the proportional contributions of bearded seal, beluga whale, bowhead whale, and ringed seal to the diets of southern Beaufort Sea polar bears. Fat biopsy samples were collected from polar bears captured or biopsy darted along the north coast of Alaska or on offshore ice during March, April, and May from 2004 to 2016. Fatty acid data of the above four prey...
By
Alaska Science Center

qfasar: Quantitative Fatty Acid Signature Analysis in R qfasar: Quantitative Fatty Acid Signature Analysis in R

Knowledge of predator diets provides numerous insights into their ecology. Diet estimation therefore remains an active area of research in quantitative ecology. Quantitative Fatty Acid Signature Analysis (QFASA) is a method of estimating the diet composition of predators. The fundamental unit of information in QFASA is a fatty acid signature (signature), which is a vector of proportions...
By
Alaska Science Center

QFASA Robustness to Assumption Violations: Computer Code QFASA Robustness to Assumption Violations: Computer Code

Quantitative fatty acid signature analysis (QFASA; Iverson et al. 2004) has become a common method of estimating diet composition, especially for marine mammals, but the performance of the method has received limited investigation. Bromaghin et al. (In press) used computer simulation to compare the bias of several QFASA estimators and developed recommendations regarding estimator...
By
Alaska Science Center

Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017 Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017

This 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...
By
Alaska Science Center

Multistate Capture and Search Data from the Southern Beaufort Sea Polar Bear Subpopulation in Alaska, 2001-2016 Multistate Capture and Search Data from the Southern Beaufort Sea Polar Bear Subpopulation 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.
By
Alaska Science Center

Fatty Acid Signature Data of Potential Yellow-billed Loon Prey in the Arctic Coastal Plain of Alaska, 2009-2011 Fatty Acid Signature Data of Potential Yellow-billed Loon Prey in the Arctic Coastal Plain of Alaska, 2009-2011

This dataset contains fatty acid data expressed as mass percent of total fatty acids for several species potentially preyed upon by yellow-billed loons. These data were utilized in a quantitative fatty acid signature analysis to estimate the diet of yellow-billed loons nesting on the Arctic Coastal Plain of Alaska.
By
Alaska Science Center

Assessing the Robustness of Quantitative Fatty Acid Signature Analysis to Assumption Violations (Supplementary Data) Assessing the Robustness of Quantitative Fatty Acid Signature Analysis to Assumption Violations (Supplementary Data)

This dataset contains fatty acid (FA) data expressed as mass percent of total FA for bearded seals, ringed seals and walrus. This is one of many datasets used in Bromaghin et al. 2016 (https://doi.org/10.1111/2041-210X.12456). These supplemental data were used in computer simulations to compare the bias of several quantitative fatty acid signature analysis (QFASA) estimators and develop...
By
Alaska Science Center

U.S. Geological Survey Polar Bear Mark-Recapture Records, Alaska Portion of the Southern Beaufort Sea, 2001-2010 U.S. Geological Survey Polar Bear Mark-Recapture Records, Alaska Portion of the Southern Beaufort Sea, 2001-2010

The dataset consists of one file of tabular data. These data include: a unique bear identification, bear sex, birth year, capture year, capture location (latitude and longitude), indicator of satellite radio status, and search effort.
By
Alaska Science Center
Aerial survey for Black Brant at Izembek Lagoon, Alaska Aerial survey for Black Brant at Izembek Lagoon, Alaska
USGS Alaska Science Center Ecosystems Analytics Program
Aerial survey for Black Brant at Izembek Lagoon, Alaska

USGS Alaska Science Center Ecosystems Analytics Program

USGS Alaska Science Center Ecosystems Analytics Program

The USGS Alaska Science Center Ecosystems Analytics program is a group of quantitative biologists and research statisticians who provide analytical support to USGS scientists to answer challenging ecological topics and management questions for USGS partners.

By
Ecosystems Mission Area, Alaska Science Center, Alaska Science Center
Aerial survey for Black Brant at Izembek Lagoon, Alaska

USGS Alaska Science Center Ecosystems Analytics Program

USGS Alaska Science Center Ecosystems Analytics Program

The USGS Alaska Science Center Ecosystems Analytics program is a group of quantitative biologists and research statisticians who provide analytical support to USGS scientists to answer challenging ecological topics and management questions for USGS partners.

By
Ecosystems Mission Area, Alaska Science Center, Alaska Science Center
Graphical abstract showing role of diet and food intake affecting polar bear population dynamics in southern Beaufort Sea.
Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea
Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea
Graphical abstract showing role of diet and food intake affecting polar bear population dynamics in southern Beaufort Sea.

Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea

Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea

This is a graphical abstract for a publication by the USGS and collaborators that examines the role of diet and food intake affecting polar bear population dynamics. Polar bears consume diets consisting of high proportions of marine mammal blubber that they access from the sea ice.

By
Alaska Science Center
Graphical abstract showing role of diet and food intake affecting polar bear population dynamics in southern Beaufort Sea.

Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea

Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea

This is a graphical abstract for a publication by the USGS and collaborators that examines the role of diet and food intake affecting polar bear population dynamics. Polar bears consume diets consisting of high proportions of marine mammal blubber that they access from the sea ice.

By
Alaska Science Center
Filter Total Items: 31

The importance of method selection when estimating diet composition with quantitative fatty acid signature analysis The importance of method selection when estimating diet composition with quantitative fatty acid signature analysis

Quantitative fatty acid signature analysis (QFASA) is a common method of estimating the composition of prey species in the diets of consumers from polar and temperate ecosystems in which lipids are an important source of energy. A key characteristic of QFASA is that the large number of fatty acids that typically comprise lipids permits the dietary contributions of a correspondingly large...
Authors
Jeffrey Bromaghin, Todd Atwood, Karyn Rode
By
Alaska Science Center

Incremental evolution of modeling a prognosis for polar bears in a rapidly changing Arctic Incremental evolution of modeling a prognosis for polar bears in a rapidly changing Arctic

Updating predictions of the response of high-profile, at-risk species to climate change and anthropogenic stressors is vital for informing effective conservation action. Here, we review two prior generations of Bayesian network probability models predicting changes in global polar bear (Ursus maritimus) population status, and provide a contemporary update based on recent research...
Authors
Bruce Marcot, Todd Atwood, David Douglas, Jeffrey Bromaghin, Anthony Pagano, Steven Amstrup
By
Alaska Science Center

Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics

Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator-prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under-ice food web to meet their energy needs. Here, we...
Authors
Karyn Rode, Brian Taras, Craig Stricker, Todd Atwood, Nicole Boucher, George Durner, Andrew Derocher, Evan Richardson, Seth Cherry, Lori Quakenbush, Lara Horstmann, Jeffrey Bromaghin
By
Ecosystems Mission Area, Alaska Science Center, Fort Collins Science Center

Summer/fall diet and macronutrient assimilation in an Arctic predator Summer/fall diet and macronutrient assimilation in an Arctic predator

Free-ranging predator diet estimation is commonly achieved by applying molecular-based tracers because direct observation is not logistically feasible or robust. However, tracers typically do not represent all dietary macronutrients, which likely obscures resource use as prey proximate composition varies and tissue consumption can be specific. For example, polar bears (Ursus maritimus)...
Authors
Craig Stricker, Karyn Rode, Brian Taras, Jeffrey Bromaghin, Lara Horstmann, Lori Quakenbush
By
Ecosystems Mission Area, Alaska Science Center, Fort Collins Science Center

Long-term variation in polar bear body condition and maternal investment relative to a changing environment 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...
Authors
Todd Atwood, Karyn Rode, David Douglas, Kristin Simac, Anthony Pagano, Jeffrey Bromaghin
By
Ecosystems Mission Area, Alaska Science Center

Survival and abundance of polar bears in Alaska’s Beaufort Sea, 2001–2016 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...
Authors
Jeffrey Bromaghin, David Douglas, George Durner, Kristin Simac, Todd Atwood
By
Ecosystems Mission Area, Alaska Science Center

Diet composition and body condition of polar bears (Ursus maritimus) in relation to sea ice habitat in the Canadian High Arctic Diet composition and body condition of polar bears (Ursus maritimus) in relation to sea ice habitat in the Canadian High Arctic

Polar bears (Ursus maritimus) rely on sea ice for hunting marine mammal prey. Declining sea ice conditions associated with climate warming have negatively affected polar bears, especially in the southern portion of their range. At higher latitudes, the transition from multi-year ice to thinner annual ice has been hypothesized to increase biological productivity and potentially improve...
Authors
Katie Florko, Gregory Thiemann, Jeffrey Bromaghin, Evan Richardson
By
Ecosystems Mission Area, Alaska Science Center

Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea

Polar bears (Ursus maritimus) are experiencing loss of sea ice habitats used to access their marine mammal prey. Simultaneously, ocean warming is changing ecosystems that support marine mammal populations. The interactive effects of sea ice and prey are not well understood yet may explain spatial‐temporal variation in the response of polar bears to sea ice loss. Here, we examined the...
Authors
Karyn Rode, Eric Regehr, Jeffrey Bromaghin, Ryan Wilson, Michelle St. Martin, Justin Crawford, Lori Quakenbush
By
Ecosystems Mission Area, Alaska Science Center

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 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)...
Authors
Todd Atwood, Jeffrey Bromaghin, Vijay Patil, George Durner, David Douglas, Kristin Simac
By
Ecosystems Mission Area, Alaska Science Center

Drivers and consequences of apex predator diet composition in the Canadian Beaufort Sea Drivers and consequences of apex predator diet composition in the Canadian Beaufort Sea

Polar bears (Ursus maritimus) rely on annual sea ice as their primary habitat for hunting marine mammal prey. Given their long lifespan, wide geographic distribution, and position at the top of the Arctic marine food web, the diet composition of polar bears can provide insights into temporal and spatial ecosystem dynamics related to climate-mediated sea ice loss. Polar bears with the...
Authors
Katie Florko, Gregory Thiemann, Jeffrey Bromaghin
By
Ecosystems Mission Area, Alaska Science Center

Dietary fat concentrations influence fatty acid assimilation patterns in Atlantic pollock (Pollachius virens) Dietary fat concentrations influence fatty acid assimilation patterns in Atlantic pollock (Pollachius virens)

A key aspect in the use of fatty acids (FA) to estimate predator diets using Quantitative FA Signature Analysis (QFASA) is the ability to account for FA assimilation through the use of calibration coefficients (CC). Here, we tested the assumption that CC are independent of dietary fat concentrations by feeding Atlantic pollock (Pollachius virens) three formulated diets with very similar...
Authors
Suzanne Budge, Katherine Townsend, Santosh Lall, Jeffrey Bromaghin
By
Ecosystems Mission Area, Alaska Science Center

Energy-rich mesopelagic fishes revealed as a critical prey resource for a deep-diving predator using quantitative fatty acid signature analysis Energy-rich mesopelagic fishes revealed as a critical prey resource for a deep-diving predator using quantitative fatty acid signature analysis

Understanding the diet of deep-diving predators can provide essential insight to the trophic structure of the mesopelagic ecosystem. Comprehensive population-level diet estimates are exceptionally difficult to obtain for elusive marine predators due to the logistical challenges involved in observing their feeding behavior and collecting samples for traditional stomach content or fecal...
Authors
Chandra Goetsch, Melinda Conners, Suzanne Budge, Yoko Mitani, William Walker, Jeffrey Bromaghin, Samantha Simmons, Colleen Reichmuth, Daniel Costa
By
Ecosystems Mission Area, Alaska Science Center

Tests of multistate CJS models to estimate survival conditioned on a partially-observed latent state Tests of multistate CJS models to estimate survival conditioned on a partially-observed latent state

Polar bears (Ursus maritimus) of the Southern Beaufort Sea (SBS) historically spent nearly the entire year on the sea ice but are increasingly using land habitat as sea ice becomes less available seasonally due to climate warming. The U.S. Geological Survey, Alaska Science Center maintains a research program on the SBS polar bear subpopulation and one important research question is...
By
Alaska Science Center

QFASA Robustness to Assumption Violations: Computer Code QFASA Robustness to Assumption Violations: Computer Code

Quantitative fatty acid signature analysis (QFASA; Iverson et al. 2004) has become a common method of estimating diet composition, especially for marine mammals, but the performance of the method has received limited investigation. Bromaghin et al. (In press) used computer simulation to compare the bias of several QFASA estimators and developed recommendations regarding estimator...
By
Ecosystems Mission Area, Species Management Research Program, Alaska Science Center

qfasar: Quantitative Fatty Acid Signature Analysis in R qfasar: Quantitative Fatty Acid Signature Analysis in R

Knowledge of predator diets provides numerous insights into their ecology. Diet estimation therefore remains an active area of research in quantitative ecology. Quantitative Fatty Acid Signature Analysis (QFASA) is a method of estimating the diet composition of predators. The fundamental unit of information in QFASA is a fatty acid signature (signature), which is a vector of proportions...
By
Alaska Science Center

Science and Products

Polar bear mother and two cubs on the Beaufort Sea ice.

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...
By
Ecosystems Mission Area, Land Management Research Program, Species Management Research Program, Alaska Science Center
Polar Bear Research

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...
Learn More
Sampling a stream in the mist in the Akilik River drainage

Ecosystems Analytics

Ecosystems Analytics is a group of quantitative biologists and research statisticians with a diverse range of expertise and experience (summarized below). We collaborate with internal and external partners to answer challenging ecological questions that are a high priority of the U.S. Geological Survey Alaska Science Center, sister agencies within the Department of the Interior (DOI), and various...
By
Ecosystems Mission Area, Alaska Science Center
Ecosystems Analytics

Ecosystems Analytics

Ecosystems Analytics is a group of quantitative biologists and research statisticians with a diverse range of expertise and experience (summarized below). We collaborate with internal and external partners to answer challenging ecological questions that are a high priority of the U.S. Geological Survey Alaska Science Center, sister agencies within the Department of the Interior (DOI), and various...
Learn More
Polar bear appears to walk on top of rippled gray water. Just behind it are very large breaking waves below a gray-blue sky.

Polar Bear Population Dynamics

Information on the status and trends of polar bear populations are needed to inform management of polar bears under US laws and international agreements. The USGS maintains a long-term research program focused on the population dynamics of the southern Beaufort Sea polar bear population. In addition, the USGS collaborates with the US Fish and Wildlife Service in population studies in the Chukchi...
By
Species Management Research Program, Alaska Science Center
Polar Bear Population Dynamics

Polar Bear Population Dynamics

Information on the status and trends of polar bear populations are needed to inform management of polar bears under US laws and international agreements. The USGS maintains a long-term research program focused on the population dynamics of the southern Beaufort Sea polar bear population. In addition, the USGS collaborates with the US Fish and Wildlife Service in population studies in the Chukchi...
Learn More

Southern Beaufort Sea Polar Bear Fatty Acid Data, Spring Samples 2004-2016 Southern Beaufort Sea Polar Bear Fatty Acid Data, Spring Samples 2004-2016

These data consist of the fatty acid composition (percent of mass) of adipose tissue samples from polar bears in Alaska's southern Beaufort Sea. Fat biopsy samples were collected from polar bears that were either captured or biopsy darted along the north coast of Alaska or on offshore ice during March, April, or May from 2004 to 2016. The data also include an identification code unique...
By
Alaska Science Center

Diet Composition of Southern Beaufort Sea Polar Bears Sampled in Spring from 2004 to 2016 Estimated with Quantitative Fatty Acid Signature Analysis Diet Composition of Southern Beaufort Sea Polar Bears Sampled in Spring from 2004 to 2016 Estimated with Quantitative Fatty Acid Signature Analysis

These data are estimates of the proportional contributions of bearded seal, beluga whale, bowhead whale, and ringed seal to the diets of southern Beaufort Sea polar bears. Fat biopsy samples were collected from polar bears captured or biopsy darted along the north coast of Alaska or on offshore ice during March, April, and May from 2004 to 2016. Fatty acid data of the above four prey...
By
Alaska Science Center

qfasar: Quantitative Fatty Acid Signature Analysis in R qfasar: Quantitative Fatty Acid Signature Analysis in R

Knowledge of predator diets provides numerous insights into their ecology. Diet estimation therefore remains an active area of research in quantitative ecology. Quantitative Fatty Acid Signature Analysis (QFASA) is a method of estimating the diet composition of predators. The fundamental unit of information in QFASA is a fatty acid signature (signature), which is a vector of proportions...
By
Alaska Science Center

QFASA Robustness to Assumption Violations: Computer Code QFASA Robustness to Assumption Violations: Computer Code

Quantitative fatty acid signature analysis (QFASA; Iverson et al. 2004) has become a common method of estimating diet composition, especially for marine mammals, but the performance of the method has received limited investigation. Bromaghin et al. (In press) used computer simulation to compare the bias of several QFASA estimators and developed recommendations regarding estimator...
By
Alaska Science Center

Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017 Polar Bear Continuous Time-Correlated Random Walk (CTCRW) Location Data Derived from Satellite Location Data, Chukchi and Beaufort Seas, July-November 1985-2017

This 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...
By
Alaska Science Center

Multistate Capture and Search Data from the Southern Beaufort Sea Polar Bear Subpopulation in Alaska, 2001-2016 Multistate Capture and Search Data from the Southern Beaufort Sea Polar Bear Subpopulation 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.
By
Alaska Science Center

Fatty Acid Signature Data of Potential Yellow-billed Loon Prey in the Arctic Coastal Plain of Alaska, 2009-2011 Fatty Acid Signature Data of Potential Yellow-billed Loon Prey in the Arctic Coastal Plain of Alaska, 2009-2011

This dataset contains fatty acid data expressed as mass percent of total fatty acids for several species potentially preyed upon by yellow-billed loons. These data were utilized in a quantitative fatty acid signature analysis to estimate the diet of yellow-billed loons nesting on the Arctic Coastal Plain of Alaska.
By
Alaska Science Center

Assessing the Robustness of Quantitative Fatty Acid Signature Analysis to Assumption Violations (Supplementary Data) Assessing the Robustness of Quantitative Fatty Acid Signature Analysis to Assumption Violations (Supplementary Data)

This dataset contains fatty acid (FA) data expressed as mass percent of total FA for bearded seals, ringed seals and walrus. This is one of many datasets used in Bromaghin et al. 2016 (https://doi.org/10.1111/2041-210X.12456). These supplemental data were used in computer simulations to compare the bias of several quantitative fatty acid signature analysis (QFASA) estimators and develop...
By
Alaska Science Center

U.S. Geological Survey Polar Bear Mark-Recapture Records, Alaska Portion of the Southern Beaufort Sea, 2001-2010 U.S. Geological Survey Polar Bear Mark-Recapture Records, Alaska Portion of the Southern Beaufort Sea, 2001-2010

The dataset consists of one file of tabular data. These data include: a unique bear identification, bear sex, birth year, capture year, capture location (latitude and longitude), indicator of satellite radio status, and search effort.
By
Alaska Science Center
Aerial survey for Black Brant at Izembek Lagoon, Alaska Aerial survey for Black Brant at Izembek Lagoon, Alaska
USGS Alaska Science Center Ecosystems Analytics Program
Aerial survey for Black Brant at Izembek Lagoon, Alaska

USGS Alaska Science Center Ecosystems Analytics Program

USGS Alaska Science Center Ecosystems Analytics Program

The USGS Alaska Science Center Ecosystems Analytics program is a group of quantitative biologists and research statisticians who provide analytical support to USGS scientists to answer challenging ecological topics and management questions for USGS partners.

By
Ecosystems Mission Area, Alaska Science Center, Alaska Science Center
Aerial survey for Black Brant at Izembek Lagoon, Alaska

USGS Alaska Science Center Ecosystems Analytics Program

USGS Alaska Science Center Ecosystems Analytics Program

The USGS Alaska Science Center Ecosystems Analytics program is a group of quantitative biologists and research statisticians who provide analytical support to USGS scientists to answer challenging ecological topics and management questions for USGS partners.

By
Ecosystems Mission Area, Alaska Science Center, Alaska Science Center
Graphical abstract showing role of diet and food intake affecting polar bear population dynamics in southern Beaufort Sea.
Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea
Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea
Graphical abstract showing role of diet and food intake affecting polar bear population dynamics in southern Beaufort Sea.

Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea

Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea

This is a graphical abstract for a publication by the USGS and collaborators that examines the role of diet and food intake affecting polar bear population dynamics. Polar bears consume diets consisting of high proportions of marine mammal blubber that they access from the sea ice.

By
Alaska Science Center
Graphical abstract showing role of diet and food intake affecting polar bear population dynamics in southern Beaufort Sea.

Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea

Role of Diet and Food Intake Affecting Polar Bear Population Dynamics in Southern Beaufort Sea

This is a graphical abstract for a publication by the USGS and collaborators that examines the role of diet and food intake affecting polar bear population dynamics. Polar bears consume diets consisting of high proportions of marine mammal blubber that they access from the sea ice.

By
Alaska Science Center
Filter Total Items: 31

The importance of method selection when estimating diet composition with quantitative fatty acid signature analysis The importance of method selection when estimating diet composition with quantitative fatty acid signature analysis

Quantitative fatty acid signature analysis (QFASA) is a common method of estimating the composition of prey species in the diets of consumers from polar and temperate ecosystems in which lipids are an important source of energy. A key characteristic of QFASA is that the large number of fatty acids that typically comprise lipids permits the dietary contributions of a correspondingly large...
Authors
Jeffrey Bromaghin, Todd Atwood, Karyn Rode
By
Alaska Science Center

Incremental evolution of modeling a prognosis for polar bears in a rapidly changing Arctic Incremental evolution of modeling a prognosis for polar bears in a rapidly changing Arctic

Updating predictions of the response of high-profile, at-risk species to climate change and anthropogenic stressors is vital for informing effective conservation action. Here, we review two prior generations of Bayesian network probability models predicting changes in global polar bear (Ursus maritimus) population status, and provide a contemporary update based on recent research...
Authors
Bruce Marcot, Todd Atwood, David Douglas, Jeffrey Bromaghin, Anthony Pagano, Steven Amstrup
By
Alaska Science Center

Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics

Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator-prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under-ice food web to meet their energy needs. Here, we...
Authors
Karyn Rode, Brian Taras, Craig Stricker, Todd Atwood, Nicole Boucher, George Durner, Andrew Derocher, Evan Richardson, Seth Cherry, Lori Quakenbush, Lara Horstmann, Jeffrey Bromaghin
By
Ecosystems Mission Area, Alaska Science Center, Fort Collins Science Center

Summer/fall diet and macronutrient assimilation in an Arctic predator Summer/fall diet and macronutrient assimilation in an Arctic predator

Free-ranging predator diet estimation is commonly achieved by applying molecular-based tracers because direct observation is not logistically feasible or robust. However, tracers typically do not represent all dietary macronutrients, which likely obscures resource use as prey proximate composition varies and tissue consumption can be specific. For example, polar bears (Ursus maritimus)...
Authors
Craig Stricker, Karyn Rode, Brian Taras, Jeffrey Bromaghin, Lara Horstmann, Lori Quakenbush
By
Ecosystems Mission Area, Alaska Science Center, Fort Collins Science Center

Long-term variation in polar bear body condition and maternal investment relative to a changing environment 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...
Authors
Todd Atwood, Karyn Rode, David Douglas, Kristin Simac, Anthony Pagano, Jeffrey Bromaghin
By
Ecosystems Mission Area, Alaska Science Center

Survival and abundance of polar bears in Alaska’s Beaufort Sea, 2001–2016 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...
Authors
Jeffrey Bromaghin, David Douglas, George Durner, Kristin Simac, Todd Atwood
By
Ecosystems Mission Area, Alaska Science Center

Diet composition and body condition of polar bears (Ursus maritimus) in relation to sea ice habitat in the Canadian High Arctic Diet composition and body condition of polar bears (Ursus maritimus) in relation to sea ice habitat in the Canadian High Arctic

Polar bears (Ursus maritimus) rely on sea ice for hunting marine mammal prey. Declining sea ice conditions associated with climate warming have negatively affected polar bears, especially in the southern portion of their range. At higher latitudes, the transition from multi-year ice to thinner annual ice has been hypothesized to increase biological productivity and potentially improve...
Authors
Katie Florko, Gregory Thiemann, Jeffrey Bromaghin, Evan Richardson
By
Ecosystems Mission Area, Alaska Science Center

Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea

Polar bears (Ursus maritimus) are experiencing loss of sea ice habitats used to access their marine mammal prey. Simultaneously, ocean warming is changing ecosystems that support marine mammal populations. The interactive effects of sea ice and prey are not well understood yet may explain spatial‐temporal variation in the response of polar bears to sea ice loss. Here, we examined the...
Authors
Karyn Rode, Eric Regehr, Jeffrey Bromaghin, Ryan Wilson, Michelle St. Martin, Justin Crawford, Lori Quakenbush
By
Ecosystems Mission Area, Alaska Science Center

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 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)...
Authors
Todd Atwood, Jeffrey Bromaghin, Vijay Patil, George Durner, David Douglas, Kristin Simac
By
Ecosystems Mission Area, Alaska Science Center

Drivers and consequences of apex predator diet composition in the Canadian Beaufort Sea Drivers and consequences of apex predator diet composition in the Canadian Beaufort Sea

Polar bears (Ursus maritimus) rely on annual sea ice as their primary habitat for hunting marine mammal prey. Given their long lifespan, wide geographic distribution, and position at the top of the Arctic marine food web, the diet composition of polar bears can provide insights into temporal and spatial ecosystem dynamics related to climate-mediated sea ice loss. Polar bears with the...
Authors
Katie Florko, Gregory Thiemann, Jeffrey Bromaghin
By
Ecosystems Mission Area, Alaska Science Center

Dietary fat concentrations influence fatty acid assimilation patterns in Atlantic pollock (Pollachius virens) Dietary fat concentrations influence fatty acid assimilation patterns in Atlantic pollock (Pollachius virens)

A key aspect in the use of fatty acids (FA) to estimate predator diets using Quantitative FA Signature Analysis (QFASA) is the ability to account for FA assimilation through the use of calibration coefficients (CC). Here, we tested the assumption that CC are independent of dietary fat concentrations by feeding Atlantic pollock (Pollachius virens) three formulated diets with very similar...
Authors
Suzanne Budge, Katherine Townsend, Santosh Lall, Jeffrey Bromaghin
By
Ecosystems Mission Area, Alaska Science Center

Energy-rich mesopelagic fishes revealed as a critical prey resource for a deep-diving predator using quantitative fatty acid signature analysis Energy-rich mesopelagic fishes revealed as a critical prey resource for a deep-diving predator using quantitative fatty acid signature analysis

Understanding the diet of deep-diving predators can provide essential insight to the trophic structure of the mesopelagic ecosystem. Comprehensive population-level diet estimates are exceptionally difficult to obtain for elusive marine predators due to the logistical challenges involved in observing their feeding behavior and collecting samples for traditional stomach content or fecal...
Authors
Chandra Goetsch, Melinda Conners, Suzanne Budge, Yoko Mitani, William Walker, Jeffrey Bromaghin, Samantha Simmons, Colleen Reichmuth, Daniel Costa
By
Ecosystems Mission Area, Alaska Science Center

Tests of multistate CJS models to estimate survival conditioned on a partially-observed latent state Tests of multistate CJS models to estimate survival conditioned on a partially-observed latent state

Polar bears (Ursus maritimus) of the Southern Beaufort Sea (SBS) historically spent nearly the entire year on the sea ice but are increasingly using land habitat as sea ice becomes less available seasonally due to climate warming. The U.S. Geological Survey, Alaska Science Center maintains a research program on the SBS polar bear subpopulation and one important research question is...
By
Alaska Science Center

QFASA Robustness to Assumption Violations: Computer Code QFASA Robustness to Assumption Violations: Computer Code

Quantitative fatty acid signature analysis (QFASA; Iverson et al. 2004) has become a common method of estimating diet composition, especially for marine mammals, but the performance of the method has received limited investigation. Bromaghin et al. (In press) used computer simulation to compare the bias of several QFASA estimators and developed recommendations regarding estimator...
By
Ecosystems Mission Area, Species Management Research Program, Alaska Science Center

qfasar: Quantitative Fatty Acid Signature Analysis in R qfasar: Quantitative Fatty Acid Signature Analysis in R

Knowledge of predator diets provides numerous insights into their ecology. Diet estimation therefore remains an active area of research in quantitative ecology. Quantitative Fatty Acid Signature Analysis (QFASA) is a method of estimating the diet composition of predators. The fundamental unit of information in QFASA is a fatty acid signature (signature), which is a vector of proportions...
By
Alaska Science Center

*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government

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