Female Pacific walruses and their calves traditionally spend summers far from shore, diving for benthic invertebrates over the shallow continental shelf waters of the Chukchi Sea. These female walruses and their calves prefer to rest between forage bouts on sea ice drifting above their feeding grounds.
Daniel H Monson, Ph.D.
Dan is a Research Wildlife Biologist with the Alaska Science Center and sea otter research lead within the Nearshore Marine Ecosystem Research Program. His work focuses on sea otter ecology and conservation including developing metrics of sea otter population status and exploring drivers of variation in sea otter foraging and demographic patterns.
Professional Experience
1995 - Present Research Wildlife Biologist, USGS, Alaska Science Center, Anchorage, Alaska
1995, 1996, 1998, 1999 Biologist, University of Minnesota, Antarctic Research Program, McMurdo, Antarctica
1992 - 1995 Graduate Research Assistant, University of California Santa Cruz, Santa Cruz, California
1992 - 1995 Statistical Assistant, NBS, Alaska Science Center, Anchorage, Alaska
1987 - 1992 Biological Technician, U.S. Fish & Wildlife Service, Anchorage, Alaska
1985 - 1987 Research Assistant, University of Minnesota, Northern Prairie Wildlife Research Center, Jamestown, North Dakota
1983 - 1985 Biological Technician, U.S. Fish & Wildlife Service, Kawishawi Field Station, Ely, Minnesota
Education and Certifications
Ph.D. 2009 University of California Santa Cruz, Santa Cruz, CA Ecology and Evolutionary Biology
M.S. 1995 University of California Santa Cruz, Santa Cruz, CA Marine Science
B.S. 1983 Luther College, Decorah, IA Biology
Affiliations and Memberships*
The Wildlife Society
American Association for the Advancement of Science
Ecological Society of America
Science and Products
Nearshore Marine Ecosystem Research
Glacier Bay National Park and Preserve Sea Otter Forage Data, 1993-2019
Intertidal Temperature Data from Kachemak Bay, Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park
Intertidal Mussel (Mytilus) Data from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park
Sea Otter Aerial Survey Data from Western Prince William Sound, Alaska, 2017
Sea Otter Aerial Survey Data from the outer Kenai Peninsula, Alaska, 2019
Sea Otter Survey Data, Carcass Recovery Data, and Blood Chemistry Data from Southwest Alaska
Morphometric and Reproductive Status Data for Sea Otters Collected or Captured in Alaska
Gulf Watch Alaska, Nearshore Component: Sea Otter Mortality Age Data from Katmai National Park and Preserve, Kenai Fjords National Park, and Prince William Sound, Alaska, 2006-2017
Gulf Watch Alaska Nearshore Component: Marine Water Quality, Water Temperature from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park, 2014-2016
Gulf Watch Alaska, Nearshore Monitoring Component: Sea Otter Foraging Observations from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park, 2012-2016
Female Pacific walruses and their calves traditionally spend summers far from shore, diving for benthic invertebrates over the shallow continental shelf waters of the Chukchi Sea. These female walruses and their calves prefer to rest between forage bouts on sea ice drifting above their feeding grounds.
Nearshore ecosystems in the Gulf of Alaska
Gene expression and wildlife health: Varied interpretations based on perspective
Revealing the extent of sea otter impacts on bivalve prey through multi-trophic monitoring and mechanistic models
Brown bear–sea otter interactions along the Katmai coast: Terrestrial and nearshore communities linked by predation
Where land and sea meet: Brown bears and sea otters
Divergent gene expression profiles in Alaskan sea otters: An indicator of chronic domoic acid exposure?
Temperature variations in the northern Gulf of Alaska across synoptic to century-long time scales
Evidence of increased mussel abundance related to the Pacific marine heatwave and sea star wasting
Abundance and distribution of sea otters (Enhydra lutris) in the southcentral Alaska stock, 2014, 2017, and 2019
Genetic variation in sea otters (Enhydra lutris) from the North Pacific with relevance to the threatened Southwest Alaska Distinct Population Segment
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
Sea otter predator avoidance behavior
Science and Products
- Science
Nearshore Marine Ecosystem Research
Nearshore ecosystems include many resources that are of high ecological, recreational, subsistence, and economic value. They also are subject to influences from a wide variety of natural and human-caused perturbations, which can originate in terrestrial or oceanic environments. Our research is designed to evaluate sources of variation in the nearshore and how they influence resources of high... - Data
Glacier Bay National Park and Preserve Sea Otter Forage Data, 1993-2019
These data describe observations of sea otter foraging behavior in Glacier Bay National Park and Preserve. Data consist of dive and surface times, success in prey retrieval, prey item, prey quantity, and size. Additionally, location of observations, and age class, sex, and pup status of the focal sea otter were also recorded.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 miSea Otter Aerial Survey Data from Western Prince William Sound, Alaska, 2017
This dataset consists of three tables related to abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in western Prince William Sound, Alaska, based on data collected during a series of population-wide aerial surveys in June 2017. The dataset consists of: (1) sea otter counts along strip transects, (2) sea otter counts in Intensive Search Unit (ISU) within the transects, andSea Otter Aerial Survey Data from the outer Kenai Peninsula, Alaska, 2019
This dataset consists of three tables related to abundance and distribution of northern sea otters (Enhydra lutris kenyoni) near the outer Kenai Peninsula, Alaska, based on data collected during a series of population-wide aerial surveys in June 2019. The dataset consists of: (1) sea otter counts along strip transects, (2) sea otter counts in Intensive Search Unit (ISU) within the transects, and (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 aMorphometric and Reproductive Status Data for Sea Otters Collected or Captured in Alaska
This dataset includes morphometric measurements and pregnancy / dependency status from sea otters captured or collected (experimental harvests or recovered after the Exxon Valdez Oil Spill) in Alaska, 1947-2019 by the U.S. Geological Survey (USGS) and the U.S. Fish and Wildlife Service (USFWS). Data collected include total body length, tail length, body mass, axillary girth, paw width, canine diamGulf Watch Alaska, Nearshore Component: Sea Otter Mortality Age Data from Katmai National Park and Preserve, Kenai Fjords National Park, and Prince William Sound, Alaska, 2006-2017
These data are part of the Gulf Watch Alaska (GWA) long term monitoring program, nearshore monitoring component. The dataset is a comma separated file exported from a Microsoft Excel spreadsheet. The data consist of information related to collection of sea otter carcasses. Collectors walked selected shorelines searching for signs of carcasses. Date, location, carcass condition, parts collected, anGulf Watch Alaska Nearshore Component: Marine Water Quality, Water Temperature from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park, 2014-2016
This data is part of the Gulf Watch Alaska (GWA) long term monitoring program, nearshore monitoring component. The data consists of date, time, and temperature measurements from intertidal rocky sampling sites. The dataset is 5 comma separated files exported from a download from the HOBO temperature logger. Sites are in Alaska and include locations in Katmai National Park and Preserve, Kenai FjorGulf Watch Alaska, Nearshore Monitoring Component: Sea Otter Foraging Observations from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park, 2012-2016
This data is part of the Gulf Watch Alaska (GWA) long term monitoring program, benthic monitoring component and a seasonal diet study in Kenai Fjords National Park. The dataset is a comma separated file exported from a Microsoft Access database. The data consists of observations made of foraging sea otters (Enhydra lutris). Observers used Questar field model spotting scopes and binoculars to ident - Multimedia
USGS Science: Walrus Haul-Out 2011
Female Pacific walruses and their calves traditionally spend summers far from shore, diving for benthic invertebrates over the shallow continental shelf waters of the Chukchi Sea. These female walruses and their calves prefer to rest between forage bouts on sea ice drifting above their feeding grounds.
ByFemale Pacific walruses and their calves traditionally spend summers far from shore, diving for benthic invertebrates over the shallow continental shelf waters of the Chukchi Sea. These female walruses and their calves prefer to rest between forage bouts on sea ice drifting above their feeding grounds.
By - Publications
Filter Total Items: 66
Nearshore ecosystems in the Gulf of Alaska
Nearshore ecosystem monitoring in western Prince William Sound, Kenai Fjords National Park, Kachemak Bay, and Katmai National Park and Preserve has been conducted as a single Nearshore Component of the Gulf Watch Alaska program over the past five years (2017-2021). This program builds on the previous five years and continues, in many cases, decades of preceding research and monitoring. During theAuthorsHeather A. Coletti, Daniel Esler, Brenda Ballachey, Jim Bodkin, George G. Esslinger, Kimberly A. Kloecker, Daniel Monson, Brian H. Robinson, Sarah Beth Traiger, Katrin Iken, Brenda Konar, Tom Dean, Mandy Lindeberg, Ben WeitzmanGene expression and wildlife health: Varied interpretations based on perspective
We evaluated wildlife population health from the perspective of statistical means vs. variances. We outlined the choices necessary to provide the framework for our study. These consisted of spatial and temporal boundaries (e.g., choice of sentinel species, populations, time frame), measurement techniques (molecular to population level), and appropriate statistical analyses. We chose to assess theAuthorsLizabeth Bowen, Julie L. Yee, James L. Bodkin, Shannon C. Waters, Michael J. Murray, Heather Coletti, Brenda E. Ballachey, Daniel Monson, A. Keith MilesRevealing the extent of sea otter impacts on bivalve prey through multi-trophic monitoring and mechanistic models
Sea otters are apex predators that can exert considerable influence over the nearshore communities they occupy. Since facing near extinction in the early 1900s, sea otters are making a remarkable recovery in Southeast Alaska, particularly in Glacier Bay, the largest protected tidewater glacier fjord in the world. The expansion of sea otters across Glacier Bay offers both a challenge to monitoringAuthorsClinton B. Leach, Benjamin P. Weitzman, James L. Bodkin, Daniel Esler, George G. Esslinger, Kimberly A. Kloecker, Daniel Monson, Jamie N. Womble, Mevin B. HootenBrown bear–sea otter interactions along the Katmai coast: Terrestrial and nearshore communities linked by predation
Sea otters were extirpated throughout much of their range by the maritime fur trade in the 18th and 19th centuries, including the coast of Katmai National Park and Preserve in southcentral Alaska. Brown bears are an important component of the Katmai ecosystem where they are the focus of a thriving ecotourism bear-viewing industry as they forage in sedge meadows and dig clams in the extensive tidalAuthorsDaniel Monson, Rebecca L. Taylor, Grant Hilderbrand, Joy Erlenbach, Heather Coletti, James L. BodkinWhere land and sea meet: Brown bears and sea otters
In Katmai National Park, Alaska, USA, we have seen changes in the number of brown bears and sea otters. The number of animals of a species a habitat can support is called carrying capacity. Even though bears live on land and sea otters live in the ocean, these two mammals share coastal habitats. Bears eat salmon, other fish, plants, clams, and beached whales. Sea otters feed on clams and other marAuthorsHeather Coletti, Grant Hilderbrand, James L. Bodkin, Brenda E. Ballachey, Joy Erlenbach, George G. Esslinger, Michael Hannam, Kimberly A. Kloecker, Buck Mangipane, Amy Miller, Daniel Monson, Benjamin Pister, K. Griffin, K. Bodkin, Tom SmithDivergent 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 chaAuthorsLizabeth Bowen, Susan Knowles, Kathi Lefebvre, Michelle St Martin, Michael Murray, Kimberly A. Kloecker, Daniel Monson, Ben Weitzman, Brenda Ballachey, Heather Coletti, Shannon C. Waters, C CummingsTemperature variations in the northern Gulf of Alaska across synoptic to century-long time scales
Surface and subsurface moored buoy, ship-based, remotely sensed, and reanalysis datasets are used to investigate thermal variability of northern Gulf of Alaska (NGA) nearshore, coastal, and offshore waters over synoptic to century-long time scales. NGA sea surface temperature (SST) showed a larger positive trend of 0.22 ± 0.10 °C per decade over 1970–2021 compared to 0.10 ± 0.03 °C per decade overAuthorsSeth L. Danielson, Tyler D. Hennon, Daniel Monson, Robert M. Suryan, Rob W. Cambell, Steven J. Baird, Kristine Holderied, Thomas J. WeingartnerEvidence 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,AuthorsSarah Beth Traiger, James L. Bodkin, Heather Coletti, Brenda Ballachey, Dean Thomas, Daniel Esler, Katrin Iken, Brenda Konar, Mandy Lindeberg, Daniel Monson, Brian H. Robinson, Robert M. Suryan, Ben WeitzmanAbundance and distribution of sea otters (Enhydra lutris) in the southcentral Alaska stock, 2014, 2017, and 2019
The Southcentral Alaska (SCAK) sea otter (Enhydra lutris) stock is the northernmost stock of sea otters, a keystone predator known for structuring nearshore marine ecosystems. We conducted aerial surveys within the range of the SCAK sea otter stock to provide recent estimates of sea otter abundance and distribution. We defined three survey regions: (1) Eastern Cook Inlet (2017), (2) Outer Kenai PeAuthorsGeorge G. Esslinger, Brian H. Robinson, Daniel H. Monson, Rebecca L. Taylor, Daniel Esler, Ben P. Weitzman, Joel Garlich-MillerGenetic variation in sea otters (Enhydra lutris) from the North Pacific with relevance to the threatened Southwest Alaska Distinct Population Segment
For the sea otter (Enhydra lutris), genetic population structure is an area of research that has not received significant attention, especially in Southwest Alaska where that distinct population segment has been listed as threatened since 2005 pursuant to the U.S. Endangered Species Act. In this study, 501 samples from 14 locations from Prince William Sound, Alaska to the Commander Islands in RussAuthorsBlair G. Flannery, Ora L. Russ, Michelle St. Martin, William S. Beatty, Kristen Worman, Joel Garlich-Miller, Verena A. Gill, Patrick R. Lemons, Daniel Monson, Kimberly A. Kloecker, Daniel Esler, John WenburgSea 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
AuthorsM. Tim Tinker, James L. Bodkin, Lizabeth Bowen, Brenda Ballachey, Gena Bentall, Alexander Burdin, Heather Coletti, George G. Esslinger, Brian B. Hatfield, Michael C. Kenner, Kimberly A. Kloecker, Brenda Konar, A. Keith Miles, Daniel Monson, Michael J. Murray, Ben Weitzman, James A. EstesSea otter predator avoidance behavior
Predators directly affect their prey as a source of mortality, and prey respond by employing antipredator strategies. Sea otters are a keystone predator within the nearshore community, but higher trophic level avian, terrestrial, and pelagic predators (e.g., bald eagles, brown bears, wolves, white sharks, and killer whales) prey on them. Three antipredator strategies used by sea otters are vigilanAuthorsDaniel Monson
*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