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
Marine predator surveys in Glacier Bay National Park and Preserve
Long-term impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality patterns
Population demographics and genetic diversity in remnant and translocated populations of sea otters
Response of Pacific walruses to disturbances from capture and handling activities at a haul-out in Bristol Bay, Alaska
Integrating ecosystem studies: A Bayesian comparison of hypotheses
Estimating survival rates with age-structure data
Flow-cytometric determination of genotoxic effects of exposure to petroleum in mink and sea otters
Population genetic studies of the sea otter (Enhydra lutris): A review and interpretation of available data
Sea Otter Enhydra lutris
Hydrocarbons in hair, livers, and intestines of sea otters (Enhydra lutris) found dead along the path of the Exxon Valdez oil spill
Hydrocarbon residues in tissues of sea otters (Enhydra lutris) collected following the Exxon Valdez Oil Spill
Hydrocarbon residues in tissues of sea otters (Enhydra lutris) collected from southeast Alaska
Science and Products
- Data
- Publications
Filter Total Items: 71
Marine predator surveys in Glacier Bay National Park and Preserve
No abstract available.AuthorsJames L. Bodkin, Kimberly A. Kloecker, H.A. Coletti, George G. Esslinger, Daniel H. Monson, Brenda E. BallacheyLong-term impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality patterns
We use age distributions of sea otters (Enhydra lutris) found dead on beaches of western Prince William Sound, Alaska, between 1976 and 1998 in conjunction with time-varying demographic models to test for lingering effects from the 1989 Exxon Valdez oil spill. Our results show that sea otters in this area had decreased survival rates in the years following the spill and that the effects of the spiAuthorsDaniel H. Monson, Daniel F. Doak, Brenda E. Ballachey, Aaron H. Johnson, James L. BodkinPopulation demographics and genetic diversity in remnant and translocated populations of sea otters
The effects of small population size on genetic diversity and subsequent population recovery are theoretically predicted, but few empirical data are available to describe those relations. We use data from four remnant and three translocated sea otter ( Enhydra lutris) populations to examine relations among magnitude and duration of minimum population size, population growth rates, and genetic variAuthorsJames L. Bodkin, Brenda E. Ballachey, M. A. Cronin, K.T. ScribnerResponse of Pacific walruses to disturbances from capture and handling activities at a haul-out in Bristol Bay, Alaska
Observations were made on hems of the Pacific walrus (Odobenus rosmarus divergens) to study their response during the capturing and handling of adult males in summer 1995 at a haul-out at Cape Peirce in southwestern Alaska. Three behaviors (alertness, displacement, and dispersal) were quantified from 16 capture sessions. Herd sizes ranged from 622 to 5,289 walruses. Handling of an immobilized walrAuthorsC.V. Jay, Tamara L. Olson, G.W. Garner, Brenda E. BallacheyIntegrating ecosystem studies: A Bayesian comparison of hypotheses
Ecosystem studies are difficult to interpret because of the complexity and number of pathways that may affect a phenomenon of interest. It is not possible to study all aspects of a problem; thus subjective judgment is required to weigh what has been observed in the context of components that were not studied but may have been important. This subjective judgment is usually a poorly documented and aAuthorsMilo D. Adkison, Brenda E. Ballachey, James L. Bodkin, Leslie E. Holland-BartelsEstimating survival rates with age-structure data
We developed a general statistical model that provides a comprehensive framework for inference about survival rates based on standing age-structure and ages-at-death data. Previously available estimators are maximum likelihood under the general model, but they use only 1 type of data and require the assumption of a stable age structure and a known population growth rate. We used the general modelAuthorsMark S. Udevitz, Brenda E. BallacheyFlow-cytometric determination of genotoxic effects of exposure to petroleum in mink and sea otters
Three experiments were conducted to investigate the genotoxic effects of crude oil on mink and sea otters, In the first experiment, the effects on mink of chronic exposure to weathered Prudhoe Bay crude oil were studied, Female mink were fed a diet that included weathered crude oil for a period of 3 weeks prior to mating, during pregnancy and until weaning. Kits were exposed through lactation andAuthorsJ. W. Bickham, J.A. Mazet, J. Blake, M.J. Smolen, Y. Lou, Brenda E. BallacheyPopulation genetic studies of the sea otter (Enhydra lutris): A review and interpretation of available data
Current information about the utility of genetic markers for estimating population structuring in sea otters (Enhydra lutris) is reviewed. Analyses of spatial population structuring with biochemical and molecular genetic markers are discussed in the context of the species' ecology and history of exploitation. Studies that have used a diversity of genetic markers including allozymes, mitochondrialAuthorsKim T. Scribner, James L. Bodkin, Brenda E. Ballachey, Steven R. Fain, Matthew A. Cronin, Maria D. SanchezSea Otter Enhydra lutris
The sea otter, Enhydra lutris, is the largest member of the Mustelidae family and is the only one which lives entirely in marine waters. Sea otters are unique among marine mammals because, unlike whales, dolphins and seals, they do not have a layer of fat or blubber to keep them warm in the cool oceans of the North Pacific. Instead, sea otters depend on dense fur that traps tiny air bubbles to insAuthorsJames L. Bodkin, Brenda E. BallacheyHydrocarbons in hair, livers, and intestines of sea otters (Enhydra lutris) found dead along the path of the Exxon Valdez oil spill
No abstract available.AuthorsBrenda E. Ballachey, Kimberly A. KloeckerHydrocarbon residues in tissues of sea otters (Enhydra lutris) collected following the Exxon Valdez Oil Spill
No abstract available.AuthorsBrenda E. Ballachey, Kimberly A. KloeckerHydrocarbon residues in tissues of sea otters (Enhydra lutris) collected from southeast Alaska
No abstract available.AuthorsBrenda E. Ballachey, Kimberly A. Kloecker
*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