Brenda Ballachey, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 72
Chemical anesthesia of Northern sea otters (Enhydra lutris): Results of past field studies Chemical anesthesia of Northern sea otters (Enhydra lutris): Results of past field studies
Between 1987 and 1997, we chemically immobilized 597 wild sea otters (Enhydra lutris) in Alaska for the collection of biological samples or for surgical instrumentation. One drug-related sea otter fatality occurred during this time. Fentanyl in combination with diazepam produced consistent, smooth inductions with minimal need for supplemental anesthetics during procedures lasting 30-40...
Authors
Daniel H. Monson, C. McCormick, Brenda E. Ballachey
Marine predator surveys in Glacier Bay National Park and Preserve Marine predator surveys in Glacier Bay National Park and Preserve
No abstract available.
Authors
James L. Bodkin, Kimberly A. Kloecker, H.A. Coletti, George G. Esslinger, Daniel H. Monson, Brenda E. Ballachey
Long-term impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality patterns Long-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...
Authors
Daniel H. Monson, Daniel F. Doak, Brenda E. Ballachey, Aaron H. Johnson, James L. Bodkin
Population demographics and genetic diversity in remnant and translocated populations of sea otters Population 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...
Authors
James L. Bodkin, Brenda E. Ballachey, M. A. Cronin, K.T. Scribner
Estimating survival rates with age-structure data Estimating 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...
Authors
Mark S. Udevitz, Brenda E. Ballachey
Response of Pacific walruses to disturbances from capture and handling activities at a haul-out in Bristol Bay, Alaska Response 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...
Authors
C.V. Jay, Tamara L. Olson, G.W. Garner, Brenda E. Ballachey
Flow-cytometric determination of genotoxic effects of exposure to petroleum in mink and sea otters Flow-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...
Authors
J. W. Bickham, J.A. Mazet, J. Blake, M.J. Smolen, Y. Lou, Brenda E. Ballachey
Integrating ecosystem studies: A Bayesian comparison of hypotheses Integrating 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...
Authors
Milo D. Adkison, Brenda E. Ballachey, James L. Bodkin, Leslie E. Holland-Bartels
Hydrocarbon residues in tissues of sea otters (Enhydra lutris) collected from southeast Alaska Hydrocarbon residues in tissues of sea otters (Enhydra lutris) collected from southeast Alaska
No abstract available.
Authors
Brenda E. Ballachey, Kimberly A. Kloecker
Population genetic studies of the sea otter (<i>Enhydra lutris</i>): A review and interpretation of available data Population genetic studies of the sea otter (<i>Enhydra lutris</i>): 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...
Authors
Kim T. Scribner, James L. Bodkin, Brenda E. Ballachey, Steven R. Fain, Matthew A. Cronin, Maria D. Sanchez
Sea Otter Enhydra lutris Sea 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...
Authors
James L. Bodkin, Brenda E. Ballachey
Hydrocarbons in hair, livers, and intestines of sea otters (Enhydra lutris) found dead along the path of the Exxon Valdez oil spill Hydrocarbons in hair, livers, and intestines of sea otters (Enhydra lutris) found dead along the path of the Exxon Valdez oil spill
No abstract available.
Authors
Brenda E. Ballachey, Kimberly A. Kloecker
Science and Products
Filter Total Items: 72
Chemical anesthesia of Northern sea otters (Enhydra lutris): Results of past field studies Chemical anesthesia of Northern sea otters (Enhydra lutris): Results of past field studies
Between 1987 and 1997, we chemically immobilized 597 wild sea otters (Enhydra lutris) in Alaska for the collection of biological samples or for surgical instrumentation. One drug-related sea otter fatality occurred during this time. Fentanyl in combination with diazepam produced consistent, smooth inductions with minimal need for supplemental anesthetics during procedures lasting 30-40...
Authors
Daniel H. Monson, C. McCormick, Brenda E. Ballachey
Marine predator surveys in Glacier Bay National Park and Preserve Marine predator surveys in Glacier Bay National Park and Preserve
No abstract available.
Authors
James L. Bodkin, Kimberly A. Kloecker, H.A. Coletti, George G. Esslinger, Daniel H. Monson, Brenda E. Ballachey
Long-term impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality patterns Long-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...
Authors
Daniel H. Monson, Daniel F. Doak, Brenda E. Ballachey, Aaron H. Johnson, James L. Bodkin
Population demographics and genetic diversity in remnant and translocated populations of sea otters Population 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...
Authors
James L. Bodkin, Brenda E. Ballachey, M. A. Cronin, K.T. Scribner
Estimating survival rates with age-structure data Estimating 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...
Authors
Mark S. Udevitz, Brenda E. Ballachey
Response of Pacific walruses to disturbances from capture and handling activities at a haul-out in Bristol Bay, Alaska Response 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...
Authors
C.V. Jay, Tamara L. Olson, G.W. Garner, Brenda E. Ballachey
Flow-cytometric determination of genotoxic effects of exposure to petroleum in mink and sea otters Flow-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...
Authors
J. W. Bickham, J.A. Mazet, J. Blake, M.J. Smolen, Y. Lou, Brenda E. Ballachey
Integrating ecosystem studies: A Bayesian comparison of hypotheses Integrating 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...
Authors
Milo D. Adkison, Brenda E. Ballachey, James L. Bodkin, Leslie E. Holland-Bartels
Hydrocarbon residues in tissues of sea otters (Enhydra lutris) collected from southeast Alaska Hydrocarbon residues in tissues of sea otters (Enhydra lutris) collected from southeast Alaska
No abstract available.
Authors
Brenda E. Ballachey, Kimberly A. Kloecker
Population genetic studies of the sea otter (<i>Enhydra lutris</i>): A review and interpretation of available data Population genetic studies of the sea otter (<i>Enhydra lutris</i>): 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...
Authors
Kim T. Scribner, James L. Bodkin, Brenda E. Ballachey, Steven R. Fain, Matthew A. Cronin, Maria D. Sanchez
Sea Otter Enhydra lutris Sea 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...
Authors
James L. Bodkin, Brenda E. Ballachey
Hydrocarbons in hair, livers, and intestines of sea otters (Enhydra lutris) found dead along the path of the Exxon Valdez oil spill Hydrocarbons in hair, livers, and intestines of sea otters (Enhydra lutris) found dead along the path of the Exxon Valdez oil spill
No abstract available.
Authors
Brenda 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