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George G Esslinger

Using new technologies to study ecosystems; sea otter ecology; geographic information systems; population estimation; predator/prey interactions.

Professional Experience

  • 1998 - Present    Zoologist, USGS, Alaska Biological Science Center Anchorage, Alaska

  • 1995 - 1998         Fish and Wildlife Biologist, USGS, Alaska Biological Science Center Anchorage, Alaska

  • 1993 - 1995         Biological Science Technician, U.S. Fish & Wildlife Service, Alaska Fish & Wildlife Research Center Anchorage, Alaska

  • 1989 - 1993         Biological Science Technician, U.S. Fish & Wildlife Service, Migratory Bird Management Anchorage, Alaska

Education and Certifications

  • M.S.   2011    University of Alaska, Anchorage, AK      Biological Sciences

  • B.S.    1993    Humboldt State University Arcata, CA    Wildlife

Science and Products

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A view of the R/V Alaskan Gyre with a glacier in the background in Harriman Fjord in Prince William Sound, Alaska

USGS Research Vessel Alaskan Gyre

The R/V Alaskan Gyre is a 50-foot fiberglass seiner that has been converted into a versatile research vessel to provide USGS scientists and collaborators with access to remote marine areas of Alaska and serve as a mobile laboratory. The vessel was built by Ledford Marine of Marysville, Washington in 1989 and is named after the Alaskan Gyre, a series of wind driven currents that rotate counter...
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Alaska Science Center
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USGS Research Vessel Alaskan Gyre

The R/V Alaskan Gyre is a 50-foot fiberglass seiner that has been converted into a versatile research vessel to provide USGS scientists and collaborators with access to remote marine areas of Alaska and serve as a mobile laboratory. The vessel was built by Ledford Marine of Marysville, Washington in 1989 and is named after the Alaskan Gyre, a series of wind driven currents that rotate counter...
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A juvenile female sea otter eating small green urchins in the intertidal. Glacier Bay near Geikie Inlet, Alaska

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...
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Ecosystems, Species Management Research Program, Alaska Science Center
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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...
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Filter Total Items: 13

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
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Alaska Science Center

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
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Alaska Science Center

Intertidal 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 at
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Alaska Science Center

Sea Otter Aerial Survey Data from Lower Cook Inlet, Alaska, 2017

This dataset consists of three tables related to abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in lower Cook Inlet, Alaska, based on data collected during a series of population-wide aerial surveys in May 2017. The dataset consists of: (1) sea otter counts along strip transects, (2) sea otter counts in Intensive Search Unit (ISU) within the transects, and (3) Transect
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Alaska Science Center

Sea 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 (
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Alaska Science Center

Sea 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, and
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Alaska Science Center

Sea Otter Aerial Survey Data from Northern and Eastern Prince William Sound, Alaska, 2014

This dataset consists of three tables related to abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in northern and eastern Prince William Sound, Alaska, based on data collected during a series of population-wide aerial surveys in June 2014. The dataset consists of: (1) sea otter counts along strip transects, (2) sea otter counts in Intensive Search Unit (ISU) within the tr
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Alaska Science Center

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 a
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Western Ecological Research Center (WERC)

Morphometric 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 diam
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Alaska Science Center

Sea Otter Aerial Survey Data from Southeast Alaska, 2002-2003

The data package "Sea Otter Aerial Survey Data from Southeast Alaska, 2002-2003" provides raw data for examining abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in Southeast Alaska, based on data collected during a series of population-wide aerial surveys. The USGS aerial sea otter surveys have been completed multiple times using consistent methodology involvin
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Alaska Science Center

Gulf Watch Alaska Nearshore Component: Sea Otter Aerial Survey Data Katmai National Park and Preserve, 2008 - 2018 (ver 2.0, March 2020)

These data are part of the Gulf Watch Alaska (GWA) long term monitoring program, nearshore monitoring component. Specifically, these data describe sea otter (Enhydra lutris) aerial survey observations from the waters around Katmai National Park and Preserve from surveys conducted in 2008, 2012, 2015, and 2018. Sea otters are a keystone predator, well known for structuring the nearshore marine ecos
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Alaska Science Center

Sea Otter Aerial Survey Data from Glacier Bay National Park and Preserve, 1999-2012

The data package "Sea Otter Aerial Survey Data from Glacier Bay National Park and Preserve, 1999-2012" provides raw data for examining abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in Glacier Bay National Park and Preserve in southeast Alaska, based on data collected during a series of population-wide aerial surveys. The USGS aerial sea otter surveys have bee
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Alaska Science Center
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Where 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 mar
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Ecosystems, Alaska Science Center

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 Pe
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Ecosystems, Alaska Science Center

Diffusion modeling reveals effects of multiple release sites and human activity on a recolonizing apex predator

BackgroundReintroducing predators is a promising conservation tool to help remedy human-caused ecosystem changes. However, the growth and spread of a reintroduced population is a spatiotemporal process that is driven by a suite of factors, such as habitat change, human activity, and prey availability. Sea otters (Enhydra lutris) are apex predators of nearshore marine ecosystems that had declined n
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Ecosystems, Alaska Science Center, Fort Collins Science Center

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

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Ecosystems, Alaska Science Center, Western Ecological Research Center (WERC)

Trends 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 compile
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Ecosystems, Alaska Science Center

The rise of an apex predator following deglaciation

AimSea otters (Enhydra lutris) are an apex predator of the nearshore marine community and nearly went extinct at the turn of the 20th century. Reintroductions and legal protection allowed sea otters to re‐colonize much of their former range. Our objective was to chronicle the colonization of this apex predator in Glacier Bay, Alaska, to help understand the mechanisms that governed their successful
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Ecosystems, Water Resources, Cooperative Research Units, Alaska Science Center, Fort Collins Science Center

Aerial surveys of sea otters (Enhydra lutris) in Lower Cook Inlet, Alaska, May, 2017

Portions of two stocks of northern sea otters (Enhydra lutris kenyoni) occur in Lower Cook Inlet (LCI), Alaska. Sea otters on the west side of LCI are considered part of the southwest Alaska stock; sea otters occupying eastern LCI are considered part of the southcentral Alaska stock. Information concerning the distributions and abundance of sea otters in LCI is needed to track the status and tre
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Ecosystems, Alaska Science Center

Monitoring dynamic spatio-temporal ecological processes optimally

Population dynamics vary in space and time. Survey designs that ignore these dynamics may be inefficient and fail to capture essential spatio‐temporal variability of a process. Alternatively, dynamic survey designs explicitly incorporate knowledge of ecological processes, the associated uncertainty in those processes, and can be optimized with respect to monitoring objectives. We describe a cohesi
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Cooperative Research Units

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
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Ecosystems, Species Management Research Program, Alaska Science Center

An integrated data model to estimate spatiotemporal occupancy, abundance, and colonization dynamics

Ecological invasions and colonizations occur dynamically through space and time. Estimating the distribution and abundance of colonizing species is critical for efficient management or conservation. We describe a statistical framework for simultaneously estimating spatiotemporal occupancy and abundance dynamics of a colonizing species. Our method accounts for several issues that are common when mo
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Cooperative Research Units

Variability within nearshore ecosystems of the Gulf of Alaska

Nearshore marine habitats, which represent the interface among air, land and sea, form a critical component of the Gulf of Alaska (GOA) ecosystem. As an interface, the nearshore facilitates transfer of water, nutrients and biota between terrestrial and oceanic systems, creating zones of high productivity. The nearshore provides a variety of ecosystem services, including (1) nursery grounds for a w
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Ecosystems, Alaska Science Center

Monitoring population status of sea otters (Enhydra lutris) in Glacier Bay National Park and Preserve, Alaska: options and considerations

After many decades of absence from southeast Alaska, sea otters (Enhydra lutris) are recolonizing parts of their former range, including Glacier Bay, Alaska. Sea otters are well known for structuring nearshore ecosystems and causing community-level changes such as increases in kelp abundance and changes in the size and number of other consumers. Monitoring population status of sea otters in Glacie
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Ecosystems, Environments Program, Alaska Science Center
Distribution map of sea otters in southcentral Alaska from aerial surveys flown in 2014, 2017, and 2019.
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Figure of density estimate of sea otters in southcentral Alaska from aerial surveys flown in 2014, 2017, and 2019.
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A layout diagram of the R/V Alaskan Gyre
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A diver holds onto a motorized device that aids in the capture of sea otters.
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View of a net to capture a sea otter, from underwater.
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The R/V Alaskan Gyre in Katmai National Park, Alaska
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