Population biology and ecology of marine mammals, population estimation, predator/prey relations, carnivora, coastal marine ecology, marine conservation.
Professional Experience
2013 - Present Research Wildlife Biologist Emeritus, USGS, Alaska Science Center, Anchorage, Alaska
1990 - 2013 Research Wildlife Biologist, USGS, Alaska Science Center, Anchorage, Alaska
1989 - 1990 Wildlife Biologist, U.S. Fish & Wildlife Service, Koyukuk Wildlife Refuge, Galena, AK
1986 - 1989 Fish and Wildlife Biologist, National Ecology Research Center, Santa Cruz, CA
Education and Certifications
M.S. 1986 California Polytechnical University, San Luis Obispo, CA Biology
B.S. 1975 California State University, Long Beach, CA Wildlife Biology
Affiliations and Memberships
Society for Conservation Biology
American Society of Mammalogy
Society for Marine Mammalogy
The Wildlife Society
Science and Products
Primary Production Sources and Bottom-up Limitations in Nearshore Ecosystems
Sea Otter Survey Data, Carcass Recovery Data, and Blood Chemistry Data from Southwest Alaska
Data for Gene Transcription Patterns in Response to Low Level Petroleum Contaminants in Mytilus trossulus from Field Sites and Harbors in Southcentral Alaska
Sea otter foraging behavior
Translocations maintain genetic diversity and increase connectivity in sea otters, Enhydra lutris
Sea otter population collapse in southwest Alaska: Assessing ecological covariates, consequences, and causal factors
Ecosystem response persists after a prolonged marine heatwave
Spatial epidemiological patterns suggest mechanisms of land-sea transmission for Sarcocystis neurona in a coastal marine mammal
Future directions in sea otter research and management
Trends and carrying capacity of sea otters in Southeast Alaska
Defining the risk landscape in the context of pathogen pollution: Toxoplasma gondii in sea otters along the Pacific Rim
Size, growth, and density data for shallow-water sea urchins from Mexico to the Aleutian Islands, Alaska, 1956–2016
Variation in abundance of Pacific Blue Mussel (Mytilus trossulus) in the Northern Gulf of Alaska, 2006–2015
Timelines and mechanisms of wildlife population recovery following the Exxon Valdez oil spill
Science and Products
- Science
Primary Production Sources and Bottom-up Limitations in Nearshore Ecosystems
Kelp forests are among the world’s most productive habitats, but recent evidence suggests that production is highly variable. - Data
Sea Otter Survey Data, Carcass Recovery Data, and Blood Chemistry Data from Southwest Alaska
Three data sets are included here to aid in assessment of the sea otter population collapse in southwest Alaska. One data set consists of results of sea otter surveys conducted between 1959 and 2015 at Bering Island, Russia and a selection of western Aleutian Islands in Alaska. Sea otter counts are reduced to a comparable value of otters per linear kilometer. Another data set consists per-capita aData 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
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Sea otter foraging behavior
Sea otters are marine specialists but diet generalists, which feed primarily on benthic mega-invertebrates (i.e., body dimension >1 cm). They locate and capture epibenthic and infaunal prey with their forepaws by relying on vision and tactile sensitivity during short-duration dives (generallyTranslocations maintain genetic diversity and increase connectivity in sea otters, Enhydra lutris
Sea otters, Enhydra lutris, were once abundant along the nearshore areas of the North Pacific. The international maritime fur trade that ended in 1911 left 13 small remnant populations with low genetic diversity. Subsequent translocations into previously occupied habitat resulted in several reintroduced populations along the coast of North America. We sampled sea otters between 2008 and 2011 throuSea 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 contaminantsEcosystem response persists after a prolonged marine heatwave
Some of the longest and most comprehensive marine ecosystem monitoring programs were established in the Gulf of Alaska following the environmental disaster of the Exxon Valdez oil spill over 30 years ago. These monitoring programs have been successful in assessing recovery from oil spill impacts, and their continuation decades later has now provided an unparalleled assessment of ecosystem responseSpatial epidemiological patterns suggest mechanisms of land-sea transmission for Sarcocystis neurona in a coastal marine mammal
Sarcocystis neurona was recognised as an important cause of mortality in southern sea otters (Enhydra lutris nereis) after an outbreak in April 2004 and has since been detected in many marine mammal species in the Northeast Pacific Ocean. Risk of S. neurona exposure in sea otters is associated with consumption of clams and soft-sediment prey and is temporally associated with runoff events. We examFuture directions in sea otter research and management
The conservation and management of sea otters has benefited from a dedicated research effort over the past 60 years enabling this species to recover from a few thousand in the early 20th century to about 150,000 today. Continued research to allow full, pre-exploitation recovery and restoration of nearshore ecosystems should focus on at least seven key challenges: 1) Defining sea otter populationsTrends and carrying capacity of sea otters in Southeast Alaska
Sea otter populations in Southeast Alaska (SEAK) have increased dramatically from fewer than 500 translocated animals in the late 1960s. The recovery of sea otters to ecosystems from which they had been absent has affected coastal food webs, including commercially important fisheries, and thus information on expected growth and equilibrium abundances can help inform resource management. We compileDefining the risk landscape in the context of pathogen pollution: Toxoplasma gondii in sea otters along the Pacific Rim
Pathogens entering the marine environment as pollutants exhibit a spatial signature driven by their transport mechanisms. The sea otter (Enhydra lutris), a marine animal which lives much of its life within sight of land, presents a unique opportunity to understand land–sea pathogen transmission. Using a dataset on Toxoplasma gondii prevalence across sea otter range from Alaska to California, we foSize, growth, and density data for shallow-water sea urchins from Mexico to the Aleutian Islands, Alaska, 1956–2016
Size, growth, and density have been studied for North American Pacific coast sea urchins Strongylocentrotus purpuratus, S. droebachiensis, S. polyacanthus, Mesocentrotus (Strongylocentrotus) franciscanus, Lytechinus pictus, Centrostephanus coronatus, and Arbacia stellata by various workers at diverse sites and for varying lengths of time from 1956 to present. Numerous peer-reviewed publications haVariation 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 l