Brenda Ballachey, Ph.D.
Population status and indices of population condition; population, physiological and ecological effects of oil exposure on marine mammals and coastal ecosystems; environmental toxicology, physiology and genetics of marine mammals.
Professional Experience
2016 - Present Research Physiologist Emeritus, USGS, Alaska Science Center, Anchorage, Alaska
1990 - 2016 Research Physiologist, USGS, Alaska Science Center, Anchorage, Alaska
1989 - 1990 Biologist, USGS, Alaska Science Center, Anchorage, Alaska
1987 - 1989 Staff Officer, Board on Agriculture, National Research Council, Washington, D.C.
1986 - 1987 Research Associate, Department of Chemistry, South Dakota State University, Brookings, South Dakota
1985 - 1985 Instructor, Department of Animal Science, Oregon State University, Corvallis, Oregon
1981 - 1985 Graduate Research Assistant, Department of Animal Science, Oregon State University, Corvallis, Oregon
1977 - 1980 Graduate Research Assistant, Department of Animal Science, Colorado State University, Ft. Collins, Colorado
Education and Certifications
Ph.D. 1985 Oregon State University, Corvallis, OR Animal Breeding and Genetics
M.S. 1980 Colorado State University, Ft. Collins, CO Animal Sciences
B.S. 1974 Colorado State University, Ft. Collins, CO Animal Science
Affiliations and Memberships*
Society for Marine Mammalogy
The Wildlife Society
Society of Environmental Toxicology and Chemistry
Science and Products
Synthesis of nearshore recovery following the 1989 Exxon Valdez oil spill: sea otter liver pathology and survival in Western Prince William Sound, 2001 – 2008
Quantifying long-term risks to sea otters from the 1989 'Exxon Valdez' oil spill: reply to Harwell & Gentile (2013)
Long-term effects of the 'Exxon Valdez' oil spill: Sea otter foraging in the intertidal as a pathway of exposure to lingering oil
Variations of transcript profiles between sea otters Enhydra lutris from Prince William Sound, Alaska, and clinically normal reference otters
Gene transcription in sea otters (Enhydra lutris); development of a diagnostic tool for sea otter and ecosystem health
Cytochrome P4501A biomarker indication of the timeline of chronic exposure of Barrow’s goldeneyes to residual Exxon Valdez oil
Could residual oil from the Exxon Valdez spill create a long-term population "sink" for sea otters in Alaska?
Trends in sea otter population abundance in western Prince William Sound, Alaska: Progress toward recovery following the 1989 Exxon Valdez oil spill
Modeling the Effects of Mortality on Sea Otter Populations
PCB exposure in sea otters and harlequin ducks in relation to history of contamination by the Exxon Valdez oil spill
Cytochrome P4501A biomarker indication of oil exposure in harlequin ducks up to 20 years after the Exxon Valdez oil spill
Stress-related hormones and genetic diversity in sea otters (Enhydra lutris)
Science and Products
- Data
- Publications
Filter Total Items: 71
Synthesis of nearshore recovery following the 1989 Exxon Valdez oil spill: sea otter liver pathology and survival in Western Prince William Sound, 2001 – 2008
We examined livers and liver biopsies collected from captured sea otters in WPWS, 2001–2008, to determine whether indicators of liver health correlated with history of oil contamination from the 1989 Exxon Valdez oil spill. Sea otters captured in oiled areas had a significantly higher proportion of livers with gross pathological change, based on visual inspection at the time of capture, than thoseAuthorsBrenda E. Ballachey, Daniel H. Monson, Kimberly A. Kloecker, George G. Esslinger, F.C. Mohr, T.P. Lipscomb, M.J. Murray, S. HowlinQuantifying long-term risks to sea otters from the 1989 'Exxon Valdez' oil spill: reply to Harwell & Gentile (2013)
Recovery of sea otter populations in Prince William Sound (PWS), Alaska, has been delayed for more than 2 decades following the 1989 ‘Exxon Valdez’ oil spill. Harwell & Gentile (2013; Mar Ecol Prog Ser 488:291–296) question our conclusions in Bodkin et al. (2012; Mar Ecol Prog Ser 447:273-287) regarding adverse effects that oil lingering in the environment may have on sea otters. They agree that eAuthorsBrenda E. Ballachey, James L. Bodkin, Daniel H. MonsonLong-term effects of the 'Exxon Valdez' oil spill: Sea otter foraging in the intertidal as a pathway of exposure to lingering oil
The protracted recovery of some bird and mammal populations in western Prince William Sound (WPWS), Alaska, and the persistence of spilled 'Exxon Valdez' oil in intertidal sediments, suggests a pathway of exposure to consumers that occupy nearshore habitats. To evaluate the hypothesis that sea otter (Enhydra lutris) foraging allows access to lingering oil, we contrast spatial relations between forAuthorsJames L. Bodkin, Brenda E. Ballachey, Heather A. Coletti, George G. Esslinger, Kimberly A. Kloecker, Stanley D. Rice, John A. Reed, Daniel H. MonsonVariations of transcript profiles between sea otters Enhydra lutris from Prince William Sound, Alaska, and clinically normal reference otters
Development of blood leukocyte gene transcript profiles has the potential to expand condition assessments beyond those currently available to evaluate wildlife health, including sea otters Enhydra lutris, both individually and as populations. The 10 genes targeted in our study represent multiple physiological systems that play a role in immuno-modulation, inflammation, cell protection, tumor supprAuthorsA. Keith Miles, Lizabeth Bowen, Brenda E. Ballachey, James L. Bodkin, M. Murray, J.L. Estes, Robin A. Keister, J.L. StottGene transcription in sea otters (Enhydra lutris); development of a diagnostic tool for sea otter and ecosystem health
Gene transcription analysis for diagnosing or monitoring wildlife health requires the ability to distinguish pathophysiological change from natural variation. Herein, we describe methodology for the development of quantitative real-time polymerase chain reaction (qPCR) assays to measure differential transcript levels of multiple immune function genes in the sea otter (Enhydra lutris); sea otter-spAuthorsLizabeth Bowen, A. Keith Miles, Michael Murray, Martin Haulena, Judy Tuttle, William van Bonn, Lance Adams, James L. Bodkin, Brenda E. Ballachey, James A. Estes, M. Tim Tinker, Robin Keister, Jeffrey L. StottCytochrome P4501A biomarker indication of the timeline of chronic exposure of Barrow’s goldeneyes to residual Exxon Valdez oil
We examined hepatic EROD activity, as an indicator of CYP1A induction, in Barrow’s goldeneyes captured in areas oiled during the 1989 Exxon Valdez spill and those from nearby unoiled areas. We found that average EROD activity differed between areas during 2005, although the magnitude of the difference was reduced relative to a previous study from 1996/1997, and we found that areas did not differ bAuthorsDaniel Esler, Brenda E. Ballachey, Kimberly A. Trust, Samuel A. Iverson, John A. Reed, A. Keith Miles, John D. Henderson, Bruce R. Woodin, John J. Stegeman, Malcolm McAdie, Daniel M. Mulcahy, Barry W. WilsonCould residual oil from the Exxon Valdez spill create a long-term population "sink" for sea otters in Alaska?
Over 20 years ago, the Exxon Valdez oil tanker spilled 42 million L of crude oil into the waters of Prince William Sound, Alaska, USA. At the time of the spill, the sea otter (Enhydra lutris) population inhabiting the spill area suffered substantial acute injuries and loss. Subsequent research has resulted in one of the best-studied species responses to an oil spill in history. However, the questiAuthorsDaniel H. Monson, Daniel F. Doak, Brenda E. Ballachey, James L. BodkinTrends in sea otter population abundance in western Prince William Sound, Alaska: Progress toward recovery following the 1989 Exxon Valdez oil spill
Sea otters in western Prince William Sound (WPWS) and elsewhere in the Gulf of Alaska suffered widespread mortality as a result of oiling following the 1989 T/V Exxon Valdez oil spill. Following the spill, extensive efforts have been directed toward identifying and understanding long-term consequences of the spill and the process of recovery. We conducted annual aerial surveys of sea otter abundanAuthorsJames L. Bodkin, Brenda E. Ballachey, George G. EsslingerModeling the Effects of Mortality on Sea Otter Populations
Conservation and management of sea otters can benefit from managing the magnitude and sex composition of human related mortality, including harvesting within sustainable levels. Using age and sex-specific reproduction and survival rates from field studies, we created matrix population models representing sea otter populations with growth rates of 1.005, 1.072, and 1.145, corresponding to stable, mAuthorsJames L. Bodkin, Brenda E. BallacheyPCB exposure in sea otters and harlequin ducks in relation to history of contamination by the Exxon Valdez oil spill
Exposure to contaminants other than petroleum hydrocarbons could confound interpretation of Exxon Valdez oil spill effects on biota at Prince William Sound, Alaska. Hence, we investigated polychlorinated biphenyls (PCBs) in blood of sea otters and harlequin ducks sampled during 1998. PCB concentrations characterized by lower chlorinated congeners were highest in sea otters from the unoiled area, wAuthorsMark A. Ricca, A. Keith Miles, Brenda E. Ballachey, James L. Bodkin, Daniel Esler, Kimberly A. TrustCytochrome P4501A biomarker indication of oil exposure in harlequin ducks up to 20 years after the Exxon Valdez oil spill
Hydrocarbon-inducible cytochrome P4501A (CYP1A) expression was measured, as ethoxyresorufin-O-deethylase (EROD) activity, in livers of wintering harlequin ducks (Histrionicus histrionicus) captured in areas of Prince William Sound, Alaska, USA, oiled by the 1989 Exxon Valdez spill and in birds from nearby unoiled areas, during 2005 to 2009 (up to 20 years following the spill). The present work repAuthorsDaniel Esler, Kimberly A. Trust, Brenda E. Ballachey, Samuel A. Iverson, Tyler L. Lewis, Daniel Rizzolo, Daniel M. Mulcahy, A. Keith Miles, Bruce R. Woodin, John J. Stegeman, John D. Henderson, Barry W. WilsonStress-related hormones and genetic diversity in sea otters (Enhydra lutris)
Sea otters (Enhydra lutris) once ranged throughout the coastal regions of the north Pacific, but were extirpated throughout their range during the fur trade of the 18th and 19th centuries, leaving only small, widely scattered, remnant populations. All extant sea otter populations are believed to have experienced a population bottleneck and thus have lost genetic variation. Populations that undergoAuthorsShawn E. Larson, Daniel H. Monson, Brenda E. Ballachey, Ronald J. Jameson, S.K. Wasser
*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