Dan is a Research Wildlife Biologist with the Alaska Science Center and leads the Nearshore Marine Ecosystem Research Program. His work focuses on nearshore marine monitoring, drivers of variation in nearshore systems, sea duck ecology and conservation, and program management.
Professional Experience
2013 - Present Research Wildlife Biologist, USGS Alaska Science Center
2001 - 2013 Research Scientist, Centre for Wildlife Ecology, Simon Fraser University, Delta, British Columbia
1990 - 2001 Research Wildlife Biologist, USGS/US Fish and Wildlife Service, Alaska Biological Science Center/Alaska Fish and Wildlife Research Center, Anchorage, Alaska
1989 - 1990 Biological Technician, US Fish and Wildlife Service, Alaska Fish and Wildlife Research Center, Anchorage, Alaska
1989 Wildlife Technician, Florida Game and Freshwater Fish Commission, Okeechobee, Florida
Education and Certifications
Ph.D. 2000 Oregon State University Wildlife Science
M.S. 1988 Texas A&M University Wildlife Ecology
B.S. 1985 Northland College Biology/Outdoor Education
Affiliations and Memberships*
Affiliate Faculty - University of Alaska Fairbanks, College of Fisheries and Ocean Sciences
Adjunct Professor - Simon Fraser University
The Wildlife Society
Pacific Seabird Group
Sea Duck Joint Venture Continental Technical Team
Science and Products
Tracking Data for Surf Scoter (Melanitta perspicillata)
Ecosystem Shifts in Arctic Seas
Nearshore Marine Ecosystem Research
Rocky Intertidal Data from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park
Intertidal Temperature Data from Kachemak Bay, Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park
Sea Otter Spraint Data from Kachemak Bay, Katmai National Park and Preserve, Kenai Fjords National Park and Prince William Sound
Intertidal Mussel (Mytilus) Data from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park
Intertidal and Subtidal Sea Otter Prey Sampling in Mixed Sediment Habitat in Glacier Bay National Park and Preserve, Alaska, 1998 to 2011
Bioenergetics and Morphology of Mussels (Mytilus trossulus) in Kenai Fjords National Park
Genetic Data from Barrow's Goldeneye and Common Goldeneye
Data for Determining Age of Barrow's Goldeneye (Bucephala islandica) from External Characteristics, Alaska and Canada, 2007-2015
Tracking Data for Surf Scoter (Melanitta perspicillata)
Intertidal Soft-Sediment Bivalves from Prince William Sound, Kachemak Bay, Katmai National Park and Preserve, and Kenai Fjords National Park
Data for Evaluating Efficacy of 1- versus 2-prong Radio Transmitter Attachment for Scoters in Alaska and Washington, 2008-2010
Data for Gene Transcription Patterns in Response to Low Level Petroleum Contaminants in Mytilus trossulus from Field Sites and Harbors in Southcentral Alaska
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
Strong evidence for two disjunct populations of Black Scoters Melanitta americana in North America
Ecosystem response persists after a prolonged marine heatwave
High site fidelity does not equate to population genetic structure for common goldeneye and Barrow's goldeneye in North America
Reliability of external characteristics to age Barrow’s goldeneye
A synthesis of ten years of chemical contaminant monitoring data in National Park Service - Southeast and southwest Alaska networks
Annual winter site fidelity of Barrow's goldeneyes in the Pacific
Wasting disease and static environmental variables drive sea star assemblages in the northern Gulf of Alaska
Attaching transmitters to waterbirds using one versus two subcutaneous anchors: Retention and survival trade-offs
Variation in abundance of Pacific Blue Mussel (Mytilus trossulus) in the Northern Gulf of Alaska, 2006–2015
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
Tracking Data for Surf Scoter (Melanitta perspicillata)
Available here are tracking data of Surf Scoter, a duck species that breeds throughout higher latitudes of Alaska and Canada and winters along coastal areas of North America. These data were collected to better understand the timing and patterns of migratory movements between breeding and wintering areas.Ecosystem Shifts in Arctic Seas
In addition to the direct effects of sea ice loss on walrus (Odobenus rosmarus divergens) and polar bears (Ursus maritimus) that use ice as a platform, the decline of Arctic sea ice is predicted to promote a fundamental ecosystem shift from benthic animals that forage on the sea floor to pelagic animals that forage near the sea surface.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
Filter Total Items: 14
Rocky Intertidal 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, nearshore monitoring component. The dataset consists of 10 tables of data organized into four folders. The data are presented in Comma Separated Value (CSV) format exported from a Microsoft Access relational database. The tables are: 1) invertebrate taxonomy, 2) limpet size, 3) limpet counts, 4) Nucella, Katharina, anIntertidal 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 downloadedSea Otter Spraint Data from Kachemak Bay, Katmai National Park and Preserve, Kenai Fjords National Park and Prince William Sound
These data are part of the Gulf Watch Alaska (GWA) long-term monitoring program. This dataset consist of observations of sea otter (Enhydra lutris) fecal samples (spraint). Observers examined fresh spraint piles to identify major prey classes in the samples and to determine sea otter diets in the Gulf of Alaska region.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 miIntertidal and Subtidal Sea Otter Prey Sampling in Mixed Sediment Habitat in Glacier Bay National Park and Preserve, Alaska, 1998 to 2011
This dataset provides clam species abundance and size data from intertidal and subtidal mixed sediment habitats in Glacier Bay National Park and Preserve (GBNPP). Data are provided for all observed clams, horse mussels, or urchins 14 mm or larger. Sampling involved excavating 25 cm of substrate from quadrats (approximately 0.25 sq meter) along transects at random and selected sites, 10 quadrats atBioenergetics and Morphology of Mussels (Mytilus trossulus) in Kenai Fjords National Park
This dataset provides one table of bioenergetic and morphological measurements of Pacific blue mussels (Mytilus trossulus; N = 444) collected at three intertidal sites in Kenai Fjords National Park, Alaska. Mussels were collected at the same tidal height across all three sites on a nearly monthly basis from 2014-2015.Genetic Data from Barrow's Goldeneye and Common Goldeneye
This data set describes nuclear microsatellite genotypes derived from eight autosomal loci (Aph02, Aph11, Aalµ1, Sfiµ4, Smo4, Smo7, Smo12, and Sfiµ8) and accession numbers for double digest restriction-site associated DNA (ddRAD) sequences.Data for Determining Age of Barrow's Goldeneye (Bucephala islandica) from External Characteristics, Alaska and Canada, 2007-2015
These data describe an exercise in which known age and sex class of 100 Barrow's goldeneyes (Bucephala islandica), determined by expert examination bursa and plumage, was contrasted with age and sex classes estimated from photos by trained observers.Tracking Data for Surf Scoter (Melanitta perspicillata)
This metadata document describes the data contained in the "rawData" folder of this data package. This data package contains all data collected by the Argos System from 25 satellite transmitters attached to Surf Scoters on their winter ranges in southeast Alaska and Baja California, Mexico, 2005-2008. Five data files are included in the "rawData" folder of this data package. Two data files (with iIntertidal Soft-Sediment Bivalves from Prince William Sound, Kachemak Bay, 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 bivalve count and size sampling and observations conducted at intertidal soft-sediment sampling sites in the northern Gulf of Alaska. This dataset consists of five comma separated files (.csv): 1) bivalve taxonomy table, 2) bivalve sampling site table, 3) bivalve count table, 4) bivalve size table, and 5)Data for Evaluating Efficacy of 1- versus 2-prong Radio Transmitter Attachment for Scoters in Alaska and Washington, 2008-2010
A major challenge of wildlife telemetry is choosing an attachment technique that maximizes transmitter retention while minimizing negative side effects. For waterbirds, attachment of transmitters with subcutaneous anchors has been an effective and well-established technique, having been used on >40 species. This method was recently modified to include a second subcutaneous anchor, presuData 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: 77
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,Abundance 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 PeGenetic 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 RussStrong evidence for two disjunct populations of Black Scoters Melanitta americana in North America
Black Scoters Melanitta americana were marked with satellite transmitters on Atlantic and Pacific coasts of North America to examine continental-scale population delineation. Scoters marked on the different coasts did not overlap at any stage of the annual cycle, suggesting that birds in the two regions could be monitored and managed as separate populations: 1) an Atlantic population, which winterEcosystem 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 responseHigh site fidelity does not equate to population genetic structure for common goldeneye and Barrow's goldeneye in North America
Delineation of population structure provides valuable information for conservation and management of species, as levels of demographic and genetic connectivity not only affect population dynamics but also have important implications for adaptability and resiliency of populations and species. Here, we measure population genetic structure and connectivity across the ranges of two sister species of sReliability of external characteristics to age Barrow’s goldeneye
Accurate assignment of age class is critical for understanding most demographic processes. For waterfowl, most techniques for determining age class require birds in hand, reducing utility for quickly and efficiently sampling a large portion of the population. As an alternative, we sought to establish an observation‐based methodology, achievable in the field with standard optics, for determining agA synthesis of ten years of chemical contaminant monitoring data in National Park Service - Southeast and southwest Alaska networks
With the exception of PAHs and trace metals, which were detected at 100% of the sites, all of the other contaminants were detected at varying frequencies. PBBs, Mirex and Endosulfans were not detected in any of the samples and Chlorpyrifos was only detected in five samples across four sites. Chlordanes were present at 79% of the sites while Butyltins were only detected at 20% of the sites. OverallAnnual winter site fidelity of Barrow's goldeneyes in the Pacific
Coastal regions on the Pacific north coast of North America provide important wintering habitat for many species of sea ducks. Although winter range and habitat preferences are well described for most species, fidelity to coastal wintering sites is generally undocumented. Fidelity is an important factor necessary for understanding interactions with coastal developments and activities and corresponWasting disease and static environmental variables drive sea star assemblages in the northern Gulf of Alaska
Sea stars are ecologically important in rocky intertidal habitats where they can play an apex predator role, completely restructuring communities. The recent sea star die-off throughout the eastern Pacific, known as Sea Star Wasting Disease, has prompted a need to understand spatial and temporal patterns of sea star assemblages and the environmental variables that structure these assemblages. We eAttaching transmitters to waterbirds using one versus two subcutaneous anchors: Retention and survival trade-offs
A major challenge of wildlife telemetry is choosing an attachment technique that maximizes transmitter retention while minimizing negative side effects. For waterbirds, attachment of transmitters with subcutaneous anchors has been an effective and well-established technique, having been used on >40 species. This method was recently modified to include a second subcutaneous anchor, presumably increVariation 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, aNon-USGS Publications**
Agüero, M. L., P. G. Borboroglu, and D. Esler. 2014. Trophic ecology of breeding white-headed steamerduck (Tachyeres leucocephalus). Waterbirds 37:88-93.Hogan, D., D. Esler, and J. E. Thompson. 2013. Duration and Phenology of Remigial Molt of Barrow's Goldeneye. Condor 115 (4):762-768Palm, E. C., D. Esler, E. M. Anderson, T. D. Williams, and M. T. Wilson. 2013. Variation in physiology and energy management of wintering white-winged scoters in relation to local habitat conditions. Condor 115 (4) :750-761.Hogan, D., D. Esler, and J. E. Thompson. 2013. Variation in body mass and foraging effort of Barrow’s goldeneyes (Bucephala islandica) during remigial molt. Auk 130 (2):313-322.Palm, E. C., D. Esler, E. M. Anderson, T. D. Williams, O. P. Love, and M. T. Wilson. 2013. Baseline corticosterone in wintering marine birds: methodological considerations and ecological patterns. Physiological and Biochemical. Zoology 86 (3):346-353.Hogan, D., J. E. Thompson, and D. Esler. 2013. Survival of Barrow’s goldeneyes during remigial molt and fall staging. Journal of Wildlife Management 77:701-706.Heath, J. P., W. A. Montevecchi, and D. Esler. 2012. A method for quantifying consistency in animal distributions using survey data. PLoS One 7(9): e44353.Palm, E. C., D. Esler, E. M. Anderson, and M. T. Wilson. 2012. Geographic and temporal variation in diet of wintering white-winged scoters. Waterbirds 35 (4):577-589.Federer, R., T. Hollmén, D. Esler, and M. J. Wooller. 2012. Stable carbon and nitrogen isotope discrimination factors for quantifying spectacled eider nutrient allocation to egg production. Condor 114:726-732.Agüero, M. L., P. G. Borboroglu, and D. Esler. 2012. Distribution and abundance of Chubut steamerducks: an endemic species to central Patagonia, Argentina. Bird Conservation International 22:307-315.Hogan, D., J. E. Thompson, D. Esler, and W. S. Boyd. 2011. Discovery of important postbreeding sites for Barrow’s goldeneye in the boreal transition zone of Alberta. Waterbirds 34(3):261-268.Takekawa, J. Y., S. W. De La Cruz, M. T. Wilson, E. C. Palm, J. Yee, D. R. Nyeswander, J. R. Evenson, J. M. Eadie, D. Esler, W. S. Boyd, and D. H. Ward. 2011. Breeding distribution and ecology of Pacific coast surf scoters. Pages 41-64 in J.V. Wells, editor. Boreal Birds of North America: a hemispheric view of their conservation links and significance. Studies in Avian Biology (Number 41). University of California Press, Berkeley.Agüero, M. L., P. G. Borboroglu, and D. Esler. 2010. Breeding habitat attributes and nest site selection of Chubut steamerducks in Patagonia, Argentina. Emu 110:302-306.Federer, R., T. Hollmén, D. Esler, M. J. Wooller, and S. W. Wang. 2010. Stable carbon and nitrogen isotope discrimination factors from diet to blood plasma, cellular blood, feathers, and adipose fatty acids in spectacled eiders (Somateria fischeri). Canadian Journal of Zoology 88(9): 866-874.Esler, D., and J. C. Bond. 2010. Cross-seasonal dynamics in body mass of male harlequin ducks: a strategy for meeting costs of reproduction. Canadian Journal of Zoology 88:224-230.Iverson, S. A., and D. Esler. 2010. Harlequin duck population dynamics following the 1989 Exxon Valdez oil spill: assessing injury and projecting a timeline to recovery. Ecological Applications 20:1993-2006.Esler, D., and S. A. Iverson. 2010. Female harlequin duck winter survival 11 to 14 years after the Exxon Valdez oil spill. Journal of Wildlife Management 74(3):471-478.Anderson, E. M., J. R. Lovvorn, D. Esler, W. S. Boyd, and K. C. Stick. 2009. Using predator distributions, diet, and condition to evaluate seasonal foraging sites: sea ducks and herring spawn. Marine Ecology Progress Series 386:287-302.Bond, J. C., S. A. Iverson, N. B. MacCallum, C. M. Smith, H. J. Bruner, and D. Esler. 2009. Variation in breeding season survival of female harlequin ducks. Journal of Wildlife Management 73: 965-972.De La Cruz, S. W., J. Y. Takekawa, M. T. Wilson, D. R. Nysewander, J. R. Evenson, D. Esler, W. S. Boyd, and D. H. Ward. 2009. Surf Scoter (Melanitta perspicillata) spring migration routes and chronology: A synthesis of Pacific coast studies. Canadian Journal of Zoology 87:1069-1086.LeBourdais, S. V., R. C. Ydenberg, and D. Esler. 2009. Fish and harlequin ducks compete on breeding streams. Canadian Journal of Zoology 87(1): 31-40.Gorman, K. B., D. Esler, R. L. Walzem, and T. D. Williams. 2009. Plasma yolk precursor dynamics during egg production by female greater scaup (Aythya marila): characterization and indices of reproductive state. Physiological and Biochemical Zoology 82(4): 372-381.Žydelis, R., D. Esler, M. Kirk, and W. S. Boyd. 2009. Effects of off-bottom shellfish aquaculture on winter habitat use by molluscivorous sea ducks. Aquatic Conservation: Marine and Freshwater Ecosystems 19:34-42.Bond, J. C., D. Esler, and T. D. Williams. 2008. Breeding propensity of female harlequin ducks. Journal of Wildlife Management 72(6):1388-1393.Lok, E. K., M. Kirk, D. Esler, and W. S. Boyd. 2008. Movements of pre-migratory surf and white-winged scoters in response to Pacific herring spawn. Waterbirds 31:385-393.Bond, J.C., and D. Esler. 2008. Bill entanglement in subcutaneously-anchored radio transmitters on harlequin ducks. Wilson Journal of Ornithology 120(3): 599-602.Gorman, K. B., D. Esler, P. L. Flint, and T. D. Williams. 2008. Nutrient reserve dynamics during egg production by female greater scaup (Aythya marila): relationships with timing of reproduction. Auk 125:384-394.Lewis, T. L., D. Esler, and W. S. Boyd. 2008. Foraging behaviors of surf and white-winged scoters in relation to clam density: inferring food availability and habitat quality. Auk 125:149-157.Kirk, M., D. Esler, and W. S. Boyd. 2007. Foraging effort of surf scoters (Melanitta perspicillata) wintering in a spatially and temporally variable prey landscape. Canadian Journal of Zoology 85(12): 1207-1215.Kirk, M., D. Esler, and W. S. Boyd. 2007. Morphology and density of mussels on natural and aquaculture structure habitats: implications for sea duck predators. Marine Ecology Progress Series 346:179-187.Bond, J. C., D. Esler, and K. A. Hobson. 2007. Isotopic evidence for sources of nutrients allocated to clutch formation by harlequin ducks. Condor 109:698-704.Iverson, S. A., and D. Esler. 2007. Survival of female harlequin ducks during wing molt. Journal of Wildlife Management 71:1220-1224.Bond, J. C., and D. Esler. 2006. Nutrient acquisition by female harlequin ducks prior to migration and reproduction: evidence for body mass optimization. Canadian Journal of Zoology 84: 1223-1229.Žydelis, R., D. Esler, W. S. Boyd, D. Lacroix, and M. Kirk. 2006. Habitat use by wintering surf and white-winged scoters: effects of environmental attributes and shellfish aquaculture. Journal of Wildlife Management 70(6):1754-1762.Iverson, S. A., and D. Esler. 2006. Site fidelity and the demographic implications of winter movements by a migratory bird, the harlequin duck. Journal of Avian Biology 37:219-228.Lewis, T. L., D. Esler, W. S. Boyd, and R. Žydelis. 2005. Nocturnal foraging behavior of wintering surf scoters and white-winged scoters. Condor 107:636-646.Lacroix, D. L., W. S. Boyd, D. Esler, M. Kirk, T. L. Lewis, and S. Lipovsky. 2005. Surf scoters aggregate in association with ephemerally abundant polychaetes. Marine Ornithology 33:61-63.Žydelis, R., and D. Esler. 2005. Response of wintering Steller’s eiders to herring spawn. Waterbirds 28:344-350.Iverson, S. A., D. Esler, and W. S. Boyd. 2003. Plumage characteristics as an indicator of age class in the surf scoter. Waterbirds 26:56-61.Weller, M. W., K. C. Jensen, E. J. Taylor, M. Miller, K. S. Bollinger, D. V. Derksen, D. Esler, and C. Markon. 1994. Assessment of shoreline vegetation in relation to use by molting black brant on the Alaska coastal plain. Biological Conservation 70:219 225.Esler, D. 1992. Habitat use by piscivorous birds on a power plant cooling reservoir. Journal of Field Ornithology 63:241 249.Esler, D. 1990. Avian community responses to hydrilla invasion. Wilson Bulletin 102:427 440.Esler, D. 1990. Waterfowl habitat use on a Texas reservoir with hydrilla. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies. 44:390 400.Esler, D. 1989. An assessment of American coot herbivory of hydrilla. Journal of Wildlife Management 53:1147 1149.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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*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