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
Intertidal Temperature Data from Kachemak Bay, Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park
These data are part of the Gulf Watch Alaska (GWA) long-term monitoring program. This dataset consists of date, time, and temperature measurements from intertidal rocky sampling sites, including predicted tide height at the time of the reading, which is used to distinguish air from water temperature readings. The data are provided as comma separated values (.csv) files derived from data downloaded
Intertidal Mussel (Mytilus) Data from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park
These data are part of the Gulf Watch Alaska (GWA) long-term monitoring program and describe mussel sampling and observations conducted in the northern Gulf of Alaska. This dataset consists of six comma separated files (.csv): 1) mussel sampling site layout information, 2) mussel counts for mussels greater than 20 millimeters in a quadrat, 3) mussel size measurements for mussels greater than 20 mi
Data for Gene Transcription Patterns in Response to Low Level Petroleum Contaminants in Mytilus trossulus from Field Sites and Harbors in Southcentral Alaska
Marine mussels are a ubiquitous and crucial component of the nearshore environment, and new genomic technologies exist to quantify molecular responses of individual mussels to stimuli, including exposure to polycyclic aromatic hydrocarbons (PAHs). We used gene-based assays of exposure and physiological function to assess lingering oil damage from the 1989 Exxon Valdez oil spill using the Pacific b
Filter Total Items: 67
Divergent gene expression profiles in Alaskan sea otters: An indicator of chronic domoic acid exposure?
An opportunistic investigation into ecosystem instability in Kachemak Bay (KBay), Alaska, has led us to investigate exposure to toxic algae in sea otters. We used gene expression to explore the physiological health of sea otters sampled in KBay in May 2019. We found altered levels of gene transcripts in comparison with reference sea otters from clinically normal, oil-exposed, and nutritionally cha
Evidence of increased mussel abundance related to the Pacific marine heatwave and sea star wasting
Mussels occupy a key middle trophic position in nearshore food webs linking primary producers to predators. Climate-related environmental changes may synergistically combine with changes in predator abundance to affect intertidal ecosystems. We examined the influence of two major events on mussel (Mytilus trossulus) abundance in the northern Gulf of Alaska: the recent Pacific marine heatwave (PMH,
Gene expression profiles in two razor clam populations: Discerning drivers of population status
With rapidly changing marine ecosystems, shifts in abundance and distribution are being documented for a variety of intertidal species. We examined two adjacent populations of Pacific razor clams (Siliqua patula) in lower Cook Inlet, Alaska. One population (east) supported a sport and personal use fishery, but this has been closed since 2015 due to declines in abundance, and the second population
Sea otter population collapse in southwest Alaska: Assessing ecological covariates, consequences, and causal factors
Sea otter (Enhydra lutris) populations in southwest Alaska declined substantially between about 1990 and the most recent set of surveys in 2015. Here we report changes in the distribution and abundance of sea otters, and covarying patterns in reproduction, mortality, body size and condition, diet and foraging behavior, food availability, health profiles, and exposure to environmental contaminants
Monitoring nearshore ecosystem health using Pacific razor clams (Siliqua patula) as an indicator species
An emerging approach to ecosystem monitoring involves the use of physiological biomarker analyses in combination with gene transcription assays. For the first time, we employed these tools to evaluate the Pacific razor clam (Siliqua patula), which is important both economically and ecologically, as a bioindicator species in the northeast Pacific. Our objectives were to (1) develop biomarker and ge
Variation in abundance of Pacific Blue Mussel (Mytilus trossulus) in the Northern Gulf of Alaska, 2006–2015
Mussels are conspicuous and ecologically important components of nearshore marine communities around the globe. Pacific blue mussels (Mytilus trossulus) are common residents of intertidal habitats in protected waters of the North Pacific, serving as a conduit of primary production to a wide range of nearshore consumers including predatory invertebrates, sea ducks, shorebirds, sea otters, humans, a
Timelines and mechanisms of wildlife population recovery following the Exxon Valdez oil spill
Research and monitoring activities over the 28 years since the T/V Exxon Valdez ran aground and spilled oil into Prince William Sound, Alaska have led to an improved understanding of how wildlife populations were damaged, as well as the mechanisms and timelines of recovery. A key finding was that for some species, such as harlequin ducks and sea otters, chronic oil spill effects persisted for at l
Gene transcription patterns in response to low level petroleum contaminants in Mytilus trossulus from field sites and harbors in southcentral Alaska
The 1989 Exxon Valdez oil spill damaged a wide range of natural resources, including intertidal communities, and post-spill studies demonstrated acute and chronic exposure and injury to an array of species. Standard toxicological methods to evaluate petroleum contaminants have assessed tissue burdens, with fewer assays providing indicators of health or physiology, particularly when contaminant lev
Cessation of oil exposure in harlequin ducks after the Exxon Valdez oil spill: Cytochrome P4501A biomarker evidence
The authors quantified hepatic hydrocarbon-inducible cytochrome P4501A (CYP1A) expression, as ethoxyresorufin-O-deethylase (EROD) activity, in wintering harlequin ducks (Histrionicus histrionicus) captured in Prince William Sound, Alaska (USA), during 2011, 2013, and 2014 (22–25 yr following the 1989 Exxon Valdez oil spill). Average EROD activity was compared between birds from areas oiled by the
Detecting and inferring cause of change in an Alaska nearshore marine ecosystem
Community composition, species abundance, and species distribution are expected to change while monitoring ecosystems over time, and effective management of natural resources requires understanding mechanisms contributing to change. Marine ecosystems in particular can be difficult to monitor, in part due to large, multidimensional spatial scales and complex dynamics. However, within the temperate
Gene transcript profiling in sea otters post-Exxon Valdez oil spill: A tool for marine ecosystem health assessment
Using a panel of genes stimulated by oil exposure in a laboratory study, we evaluated gene transcription in blood leukocytes sampled from sea otters captured from 2006–2012 in western Prince William Sound (WPWS), Alaska, 17–23 years after the 1989 Exxon Valdez oil spill (EVOS). We compared WPWS sea otters to reference populations (not affected by the EVOS) from the Alaska Peninsula (2009), Katmai
Long-term monitoring program: Evaluating chronic exposure of harlequin ducks and sea otters to lingering Exxon Valdez Oil in Western Prince William Sound
We found that average cytochrome P4501A induction (as measured by EROD activity) during March 2014 was not elevated in wintering harlequin ducks captured in areas of Prince William Sound oiled by the 1989 Exxon Valdez oil spill, relative to those captured in unoiled areas. This result is consistent with findings from March 2013. We interpret these findings to indicate that exposure of harlequin du
Science and Products
- Data
Intertidal Temperature Data from Kachemak Bay, Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park
These data are part of the Gulf Watch Alaska (GWA) long-term monitoring program. This dataset consists of date, time, and temperature measurements from intertidal rocky sampling sites, including predicted tide height at the time of the reading, which is used to distinguish air from water temperature readings. The data are provided as comma separated values (.csv) files derived from data downloadedIntertidal Mussel (Mytilus) Data from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park
These data are part of the Gulf Watch Alaska (GWA) long-term monitoring program and describe mussel sampling and observations conducted in the northern Gulf of Alaska. This dataset consists of six comma separated files (.csv): 1) mussel sampling site layout information, 2) mussel counts for mussels greater than 20 millimeters in a quadrat, 3) mussel size measurements for mussels greater than 20 miData for Gene Transcription Patterns in Response to Low Level Petroleum Contaminants in Mytilus trossulus from Field Sites and Harbors in Southcentral Alaska
Marine mussels are a ubiquitous and crucial component of the nearshore environment, and new genomic technologies exist to quantify molecular responses of individual mussels to stimuli, including exposure to polycyclic aromatic hydrocarbons (PAHs). We used gene-based assays of exposure and physiological function to assess lingering oil damage from the 1989 Exxon Valdez oil spill using the Pacific b - Publications
Filter Total Items: 67
Divergent gene expression profiles in Alaskan sea otters: An indicator of chronic domoic acid exposure?
An opportunistic investigation into ecosystem instability in Kachemak Bay (KBay), Alaska, has led us to investigate exposure to toxic algae in sea otters. We used gene expression to explore the physiological health of sea otters sampled in KBay in May 2019. We found altered levels of gene transcripts in comparison with reference sea otters from clinically normal, oil-exposed, and nutritionally chaEvidence of increased mussel abundance related to the Pacific marine heatwave and sea star wasting
Mussels occupy a key middle trophic position in nearshore food webs linking primary producers to predators. Climate-related environmental changes may synergistically combine with changes in predator abundance to affect intertidal ecosystems. We examined the influence of two major events on mussel (Mytilus trossulus) abundance in the northern Gulf of Alaska: the recent Pacific marine heatwave (PMH,Gene expression profiles in two razor clam populations: Discerning drivers of population status
With rapidly changing marine ecosystems, shifts in abundance and distribution are being documented for a variety of intertidal species. We examined two adjacent populations of Pacific razor clams (Siliqua patula) in lower Cook Inlet, Alaska. One population (east) supported a sport and personal use fishery, but this has been closed since 2015 due to declines in abundance, and the second populationSea otter population collapse in southwest Alaska: Assessing ecological covariates, consequences, and causal factors
Sea otter (Enhydra lutris) populations in southwest Alaska declined substantially between about 1990 and the most recent set of surveys in 2015. Here we report changes in the distribution and abundance of sea otters, and covarying patterns in reproduction, mortality, body size and condition, diet and foraging behavior, food availability, health profiles, and exposure to environmental contaminants
Monitoring nearshore ecosystem health using Pacific razor clams (Siliqua patula) as an indicator species
An emerging approach to ecosystem monitoring involves the use of physiological biomarker analyses in combination with gene transcription assays. For the first time, we employed these tools to evaluate the Pacific razor clam (Siliqua patula), which is important both economically and ecologically, as a bioindicator species in the northeast Pacific. Our objectives were to (1) develop biomarker and geVariation in abundance of Pacific Blue Mussel (Mytilus trossulus) in the Northern Gulf of Alaska, 2006–2015
Mussels are conspicuous and ecologically important components of nearshore marine communities around the globe. Pacific blue mussels (Mytilus trossulus) are common residents of intertidal habitats in protected waters of the North Pacific, serving as a conduit of primary production to a wide range of nearshore consumers including predatory invertebrates, sea ducks, shorebirds, sea otters, humans, aTimelines and mechanisms of wildlife population recovery following the Exxon Valdez oil spill
Research and monitoring activities over the 28 years since the T/V Exxon Valdez ran aground and spilled oil into Prince William Sound, Alaska have led to an improved understanding of how wildlife populations were damaged, as well as the mechanisms and timelines of recovery. A key finding was that for some species, such as harlequin ducks and sea otters, chronic oil spill effects persisted for at lGene transcription patterns in response to low level petroleum contaminants in Mytilus trossulus from field sites and harbors in southcentral Alaska
The 1989 Exxon Valdez oil spill damaged a wide range of natural resources, including intertidal communities, and post-spill studies demonstrated acute and chronic exposure and injury to an array of species. Standard toxicological methods to evaluate petroleum contaminants have assessed tissue burdens, with fewer assays providing indicators of health or physiology, particularly when contaminant levCessation of oil exposure in harlequin ducks after the Exxon Valdez oil spill: Cytochrome P4501A biomarker evidence
The authors quantified hepatic hydrocarbon-inducible cytochrome P4501A (CYP1A) expression, as ethoxyresorufin-O-deethylase (EROD) activity, in wintering harlequin ducks (Histrionicus histrionicus) captured in Prince William Sound, Alaska (USA), during 2011, 2013, and 2014 (22–25 yr following the 1989 Exxon Valdez oil spill). Average EROD activity was compared between birds from areas oiled by theDetecting and inferring cause of change in an Alaska nearshore marine ecosystem
Community composition, species abundance, and species distribution are expected to change while monitoring ecosystems over time, and effective management of natural resources requires understanding mechanisms contributing to change. Marine ecosystems in particular can be difficult to monitor, in part due to large, multidimensional spatial scales and complex dynamics. However, within the temperateGene transcript profiling in sea otters post-Exxon Valdez oil spill: A tool for marine ecosystem health assessment
Using a panel of genes stimulated by oil exposure in a laboratory study, we evaluated gene transcription in blood leukocytes sampled from sea otters captured from 2006–2012 in western Prince William Sound (WPWS), Alaska, 17–23 years after the 1989 Exxon Valdez oil spill (EVOS). We compared WPWS sea otters to reference populations (not affected by the EVOS) from the Alaska Peninsula (2009), KatmaiLong-term monitoring program: Evaluating chronic exposure of harlequin ducks and sea otters to lingering Exxon Valdez Oil in Western Prince William Sound
We found that average cytochrome P4501A induction (as measured by EROD activity) during March 2014 was not elevated in wintering harlequin ducks captured in areas of Prince William Sound oiled by the 1989 Exxon Valdez oil spill, relative to those captured in unoiled areas. This result is consistent with findings from March 2013. We interpret these findings to indicate that exposure of harlequin du
*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