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Jeffrey Bromaghin, Ph.D.

My research broadly encompasses the development and application of statistical methods and models to improve our understanding of ecological processes that influence the survival, behavior, and reproduction of individual animals, and how individual-animal outcomes ultimately scale upward to shape the dynamics and demographics of entire populations and communities through time and space.

My research involves the development and application of new analytical methods and models to improve our understanding of wildlife population ecology, with a current emphasis on polar bears and other DOI trust species residing in Arctic and sub-Arctic ecosystems. Past work has included nest survival models, applications of genetics in wildlife models, size selectivity and the effects of selective exploitation, animal response to capture and handling, and mark-recapture methodology. Most current research involves the development of mark-recapture and integrated population models to improve our understanding of polar bear population dynamics in a warming Arctic and the use of biotracers (e.g. fatty acids, stable isotopes) to estimate predator diet composition and animal origins and movements. Research products provide valuable information to the public and management authorities from local to international levels, and many have broad applicability that advance the discipline of statistical ecology.

Professional Experience

  • 2009 - Present   Research Statistician, U.S. Geological Survey, Alaska Science Center

  • 2000 - 2009       Statistician, U.S. Fish and Wildlife Service, Fisheries and Ecological Services, Alaska Region

  • 1990 - 2000       Regional Biometrician, Alaska Dept. of Fish and Game, Commercial Fisheries Division

Education and Certifications

  • Ph.D.    1991    University of Wyoming    Statistics

  • M.S.     1988    University of Wyoming    Statistics

  • B.S.      1985    University of Alaska        Wildlife Management

Affiliations and Memberships*

  • The International Biometric Society

  • The Wildlife Society

  • Ecological Society of America

Honors and Awards

  • 2014    U. S. Geological Survey, Quality step increase for exceptional performance

  • 2014    U. S. Geological Survey, STAR award for special achievement

  • 2012    U. S. Geological Survey, STAR award for special achievement

  • 2012    Stevan Phelps Award, American Fisheries Society (Bromaghin et al., 2011, TAFS 140:235-249)

  • 2011     U. S. Geological Survey, STAR award for special achievement

  • 2010    U. S. Geological Survey, STAR award for special achievement

  • 2007   U. S. Fish and Wildlife Service, STAR award for exceptional performance

  • 2007   U. S. Fish and Wildlife Service, Regional Director’s award for Science Excellence

  • 2004   U. S. Fish and Wildlife Service, quality step increase for sustained exceptional performance

  • 2001    U. S. Fish and Wildlife Service, STAR award for outstanding performance

  • 1993    Letter of commendation, Alaska Dept. Fish and Game

  • 1992    Deming Award for distinguished graduate program. Dept. of Statistics, University of Wyoming

Science and Products

Filter Total Items: 29

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 assessed whe
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Ecosystems, Alaska Science Center, Fort Collins Science Center

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) preferentia
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Ecosystems, Alaska Science Center, Fort Collins Science Center

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
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Ecosystems, Alaska Science Center

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
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Ecosystems, Alaska Science Center

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 polar bear f
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Ecosystems, Alaska Science Center

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 potential com
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Ecosystems, 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

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
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Ecosystems, Alaska Science Center

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 greatest ecol
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Ecosystems, Alaska Science Center

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 FA proport
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Ecosystems, Alaska Science Center

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 analyses. We
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Ecosystems, Alaska Science Center

QFASAR: Quantitative fatty acid signature analysis with R

Knowledge of predator diets provides essential insights into their ecology, yet diet estimation is challenging and remains an active area of research.Quantitative fatty acid signature analysis (QFASA) is a popular method of estimating diet composition that continues to be investigated and extended. However, software to implement QFASA has only recently become publicly available.I summarize a new R
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Ecosystems, Alaska Science Center

Simultaneous estimation of diet composition and calibration coefficients with fatty acid signature data

Knowledge of animal diets provides essential insights into their life history and ecology, although diet estimation is challenging and remains an active area of research. Quantitative fatty acid signature analysis (QFASA) has become a popular method of estimating diet composition, especially for marine species. A primary assumption of QFASA is that constants called calibration coefficients, which
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Ecosystems, Alaska Science Center
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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...
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Alaska Science Center
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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
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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...
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Species Management Research Program, Alaska Science Center
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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

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
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Alaska Science Center

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.
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Alaska Science Center

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 (Haynes et al. 2015).
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Alaska Science Center

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

These data were collected by the U.S. Geological Survey, Alaska Science Center, Polar Bear Research Program as part of long-term on the southern Beaufort Sea polar bear population.
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Alaska Science Center
Graphical abstract showing role of diet and food intake affecting polar bear population dynamics in southern Beaufort Sea.
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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 selection. Simula
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Ecosystems, Species Management Research Program, Alaska Science Center

Science and Products

*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