NPRB Use Only
Reference No 43
Date Submitted December 01, 2006
Date Received
Project Title:
Threatened southwest Alaska sea otter stock: delineating the causes and constraints to recovery
of a keystone predator in the North Pacific Ocean.
Project Period:
from October, 2007 to April, 2010
Name, Address, Telephone Number and Email Address of Applicant:
Dr. James A Estes
Alaska SeaLife Center
8314592357
8314592249
jestes@ucsc.edu
100 Shaffer Rd, Santa Cruz, California 95060, USA
Principal Investigator(s): (Include name, affiliation and email address):
Dr. James A Estes, Alaska SeaLife Center, jestes@ucsc.edu
Research Priority:
Sea otters
Summary of Proposed Work: The decline in the SW Alaska sea otter stock extends from the western end of the
Aleutian archipelago eastward to somewhere between the ShumaginIslands and the Kodiak archipelago. Although
Killer whale predation is apparently a significant cause of the decline in the Aleutians, the eastern extent of the decline
and the role of predation in this region are unknown. The nearshore marine ecosystem in the central and western
Aleutians has changed markedly over the past 15 years. The present-day system is characterized by extremely low
sea otter densities, large increases in the macro-invertebrates that sea otters prey upon (primarily sea urchins), and
corresponding declines in the abundance of kelps as a result of urchin grazing. We will use the observed direct
(reduced sea otter densities) and indirect consequences of Killer whale predation (change in body size, increased food
availability, modified behavior and habitat use) to; 1) delineate the eastern extent of the sea otter decline, 2) evaluate
the role of predation as a consistent cause within the area of decline, and 3) evaluate factors other than predation as
potentially constraining recovery. These project goals will be met through the collection of systematic data at a series
of locations extending eastward from the Andreanof Islands in the Central Aleutians to Cook Inlet. These data will be
integrated with information from Bering Island, Russia, the western Aleutian Islands, the Kodiak archipelago, and
Prince William Sound to establish a transect of relevant information across and beyond the range of the decline.
Total Funding Requested From NPRB:
$ 299,807.00 Alaska SeaLife Center
$ 299,807.00
Total Other Support:
$ 38,546.00 Alaska SeaLife Center
$ 84,744.00 U.S. Geological Survey, Western Ecological Research Center
$ 140,690.00 U.S. Geological Survey, Alaska Science Center
$ 263,980.00
Legally Binding Authorizing Signature and Affiliation:
Estes and Bodkin Research Plan
A. Project Title
Threatened southwest Alaska sea otter stock: delineating the causes and constraints to recovery
of a keystone predator in the North Pacific Ocean.
Short Title: Sea otter decline
B. Proposal Summary
Populations of several marine mammal species have declined precipitously over the last several
decades. Understanding and mitigating these declines is a pressing issue for the management and
conservation of Alaska’s marine resources. The decline in the SW Alaska sea otter stock extends
from the western end of the Aleutian archipelago eastward to somewhere between the Shumagin
Islands and the Kodiak archipelago. Although Orca predation is apparently a significant cause of
the decline in the Aleutians, the eastern extent of the decline and the role of predation in this
region are unknown. The nearshore marine ecosystem in the central and western Aleutians has
changed markedly over the past 15 years. The present-day system is characterized by extremely
low sea otter densities, large increases in the macro-invertebrates that sea otters prey upon
(primarily sea urchins), and corresponding declines in the abundance of kelps. We will use the
observed direct (reduced otter densities) and indirect consequences of Orca predation (change in
body size, increased food availability, modified behavior and habitat use) to; 1) delineate the
eastern extent of the sea otter decline, 2) evaluate the role of predation as a consistent cause
within the area of decline, and 3) evaluate various other factors that may be constraining
recovery. These project goals will be met through the collection of similar data at a series of
locations extending eastward from the Andreanof Islands in the Central Aleutians to Cook Inlet.
These data will be integrated with those available from Bering Island, Russia, the western
Aleutian Islands, the Kodiak archipelago, and Prince William Sound to establish a transect of
information across and beyond the range of the sea otter decline.
C. Project Responsiveness to NPRB Research Priorities or Identified Project Needs
The 2007 NPRB call for proposals on General Research Priorities on Ecosystems Components
identified the recent sea otter decline as a specific topic under the Marine Mammal section. Our
proposed research follows NPRB’s request for studies to assess the likely causes for the decline
(particularly those that have not already been investigated) and factors affecting population
recovery. We will delineate the eastern extent of the decline. We also will further assess the
suite of potential factors responsible for the decline, the potential factors affecting population
recovery, and how these may vary geographically across the sea otter’s range in southwest
Alaska. The sea otter decline is part of a larger overall collapse of coastal-living marine mammal
species in southwest Alaska, including harbor seals, northern fur seals, and Steller sea lions.
These declines are of great concern to marine resource management and conservation.
Understanding the causes and consequences of these declines, and those preventing recovery, is
a more tractable goal for sea otters than for the other marine mammal species.
D. Soundness of Project Design and Conceptual Approach:
Estes and Bodkin Research Plan
In about 1990, sea otter populations began declining rapidly over large areas of southwest Alaska
(Estes et al. 1998, Doroff et al. 2003, Burn et al. 2003). The declines in many areas are now
approaching two orders of magnitude (Estes et al. 2005) and there is concern over the possibility
of localized or even larger-scale extinctions of sea otters from a region where the species
abounded just 15 years ago. Like most large scale wildlife population declines, this one was
unanticipated. Therefore, the available data to evaluate the specific causes of the decline are few.
The only data that are available for making such inferences come from the central and western
Aleutian Islands where field studies of sea otters and coastal ecosystems were fortuitously being
conducted during the time of the decline.
Post-hoc analyses and interpretation of the earlier data led Estes and colleagues to conclude that
killer whale predation was the most likely cause of the decline (Estes et al. 1998, 2004, Williams
et al. 2004). In brief, this conclusion was based on the following evidence:
1) increased killer whale sightings in coastal waters (from one or fewer per year to
several per day) at about the onset of the decline;
2) a significant increase in the observed killer whale attack rate on sea otters during the
period of the decline;
3) the absence of localized population declines in habitats that afforded refuge to sea
otters from killer whale predation;
4) the results of demographic and energetic analyses indicating that a) the observed
number of attacks was similar to that expected if killer whale predation was entirely
responsible for the decline and b) all of the missing sea otters could be accounted for by a
small change in killer whale foraging behavior (i.e., several animals switching to a diet of
sea otters or the entire population of transient killer whales altering their diets by just
several percent).
Other potential explanations for the decline include demographic stochasticity, nutritional
limitation, disease, toxic substances (naturally occurring or anthropogenic), and incidental or
illegal take. Human take has been discounted because human settlements and human activity in
coastal waters are virtually absent from this part of the world. Based on the geographic range and
time course of the decline, demographic stochasticity also seems highly unlikely. The absence of
stranded carcasses, improved body condition over the course of the decline (Laidre et al. 2006),
increased food availability, and a reduction in time spent foraging over the course of the decline
are inconsistent with nutritional limitation (Estes et al. 2004). Health and disease screening in the
living animals and contaminant assays inform living and dead animals do not indicate that these
factors have caused or contributed to the declines (Estes et al. 1998, Hanni et al. 2003, Reese et
al. in review, Estes, unpubl. data). Finally, the distribution of the surviving animals has shifted
markedly shoreward, and when alarmed, sea otters now often take refuge on land, a behavior we
never saw prior to the decline. We interpret this new behavior as potential avoidance responses
to predation.
Although killer whale predation is the leading hypothesis for the cause of the sea otter decline in
the Aleutian Islands, there are outstanding points of uncertainty or debate. One of these is the
geographical extent of the decline. While the western end of the population decline is both
clearly established (between the Near and Commander islands—Fig. 1) and sharply punctuated
Estes and Bodkin Research Plan
(populations in the Near Islands have declined as precipitously and deeply as anywhere; those in
the Commander Islands have not declined at all), the decline in the east is poorly known. Sea
otter numbers have declined in the Shumagin Islands (southwest Alaska Peninsula) and along the
northwest side of the Alaska Peninsula (USFWS unpubl. data and pers. comm.). However, there
is no indication of a decline in the Kodiak archipelago or areas further east (Bodkin et al. 2002,
USFWS and USGS, unpublished data). Understanding the true spatial extent of the decline is
critical to understanding if it is stable or spreading, if it is sharply punctuated (as in the west) or
gradual, and if it is in fact geographically coincident with the harbor seal and sea lion declines.
Whether infectious diseases caused or contributed to the decline, or are inhibiting population
recovery, are questions of growing interest and concern. A relatively large number of stranded
carcasses have been reported in Kachemak Bay in recent years, and valvular endocarditis is the
cause of death in a high proportion of those that have been necropsied. Whether this is truly an
emerging disease, an epiphenomenon of high population density and resource limitation, or the
result of some as yet unknown cause remains uncertain. Nonetheless, the U.S. Fish and Wildlife
Service recently designated the increased number of standings as an Unusual Mortality Event,
heightening concerns that disease may be a factor limiting recovery of the Threatened SW
Alaska sea otter stock. Furthermore, blood serum assays from living sea otters in some areas
indicate exposure to morbilliviruses. These findings are equivocal because of inconsistencies in
the results from different diagnostic laboratories, and it remains uncertain whether positive test
results are indicative of disease exposure. Even so, the disease issue clearly requires further
information and analysis.
General approach and study design
It is important to recognize that there probably always will be doubt and debate over the cause of
the sea otter decline in southwest Alaska. This is because the evidence for or against each of the
potential drivers of population change is subject to uncertainty and differing interpretations. For
example, since predation events occur almost instantaneously and over large expanses of space
and time, the expected number of observed attacks will be exceedingly small under even the
most ideal circumstances. We know this to be true on theoretical grounds and from our field
experience in the Aleutian Islands during the early 1990s (e.g., see Estes et al. 1998, 2004). The
expected number of attacks in an already depleted population would be even fewer. Thus, it
would be imprudent to mount a field program with the a priori intent of directly measuring
predation rates. Similarly, the demographic consequences of diseases are often difficult to infer.
Evidence for disease exposure by itself means relatively little as individual animals can be
exposed to diseases without being impacted by them. Even unequivocal evidence for diseaseinduced mortality in large numbers of stranded carcasses doesn’t necessarily indicate an
epidemic or a disease-induced population decline because deteriorating health and disease are
common manifestations of high population density and resource limitation.
These difficulties notwithstanding, the differing explanations of the sea otter population decline
lead to differing expectations of pattern in the sea otters themselves and in their ecosystem.
Therefore a meta-type analysis of the relevant data obtained over the appropriate scale of space
and time can be revealing. Without some new and unforeseeable event and based solely on a
continued focused study of sea otters in the west/central Aleutian Islands, it probably will not be
Estes and Bodkin Research Plan
possible to advance a much stronger argument than already has been made for the cause of the
sea otter decline in that region. However, using the data from the central/western Aleutians as
both a model of expectation and a point of comparison, it will be relatively straightforward to
establish the eastern extent of the decline and to assess whether the sea otter declines in different
areas of southwest Alaska have similar or differing associated patterns, and thus to infer whether
they resulted from common or differing causes.
We will employ this general approach by obtaining a common suite of measurements from sea
otters and their environments at a number of sites across the sea otter’s range, from Bering Island
in the west to Prince William Sound in the east. Although Bering Island and Prince William
Sound currently lie beyond the western and eastern extremes of the decline, the fact that sea otter
populations are abundant and at or near environmental carrying capacity in both areas make them
important points of comparison. If there is a common cause across the geographic range of
decline, then we would expect to see this manifested as common patterns across this range.
Conversely, variable patterns between the western and eastern regions of the decline would
suggest differing causes. For example, the nearly complete absence of beach-cast carcasses in the
central/western Aleutian Islands has been interpreted as being most consistent with the killer
whale predation hypothesis. If starvation, toxic materials, or diseases were responsible for
declines elsewhere, we would expect to see indirect evidence for this in the form of more
abundant stranded carcass remains (e.g., scattered bones, even in areas that are extensively
scavenged) on the beaches.
To reiterate, we do not propose to test the killer whale predation hypothesis by obtaining
observations of the rate at which sea otters are attacked by killer whales. This is not an
achievable objective. Instead, we have established a small number of reasonable alternative
hypotheses for the cause of the sea otter population declines, formulated a suite of correlated
response variables in the sea otters and their coastal ecosystems that will vary in predictable
ways under each hypothesis, and will evaluate the cause or causes of the decline over its entire
range across the North Pacific rim by measuring the patterns of variation in these response
variables at a relatively large number of selected sites throughout and beyond this range.
Proposed Research
We will use NPRB funding to add study sites to our existing sea otter research programs that will
fill in critical data gaps for understanding the full geographic extent of the decline and its causes.
We will collect the following common data sets, using standard and well tested protocols, from
13 locations (Fig. 1) across the longitudinal range of the decline: 1) sea otter population density
and distance from shore; 2) carcass encounter rates in beach surveys; 3) food availability and
benthic community structure from diving surveys; and 4) the net rate of energy gain from
foraging sea otters. We will also conduct experiments to evaluate the behavioral response of sea
otters living within and beyond the range of the decline to simulated visual and auditory killer
whale cues.
From our current and recently completed studies, we have partial or complete data sets for 5 of
the 13 sites (Nos. 1, 2, 9, 10, and 13). In addition, population survey data are available for 2 sites
(Nos. 6 and 8). We are requesting funding to complete the data collection across and beyond the
Estes and Bodkin Research Plan
range of the population decline. This will be done in two phases. In Phase one, to be conducted
in 2008, we will conduct the population surveys of living animals, assess prey availability,
conduct the beach surveys for carcass remains, and begin the foraging efficiency analyses. In
Phase two, to be conducted in 2009, we will capture living animals from several of these sites for
health screening and body condition.
In the body condition and health screening analysis, we will look for evidence of disease
exposure in otters between nearby areas where sea otter populations have and have not declined.
This will be done at both the western and eastern ends of the range of the overall population
decline. For this analysis, we will obtain the following samples and information: a)
Morphometric measures (length, weight, girth); b) a premolar tooth (for age estimates) c) whole
blood (Hgb, hematocrit RBC counts, WBC counts, WBC differential counts); d) blood serum
and plasma (serology, serum chemistry, and serum or plasma serology for antibodies to or
antigens of selected infectious diseases); e) nasal, rectal, and vaginal/preputial swabs; and f)
fecal culture swabs (protozoal parasite evaluation). These data will be obtained from 4 sites-Bering Island; western/central Aleutian Islands; and two comparable sites in the east, to be
determined from the 2008 survey results. Information on sea otter body condition, health and
disease is currently available from live animal captures at several of these locations, including
Bering Island, the central/western Aleutian Islands, Prince William Sound, and the Kodiak
archipelago. Our efforts will be mainly to fill out the necessary information so that the contrasts
can be done in a rigorous and consistent manner.
PHASE ONE
Density and Distribution: We will conduct skiff surveys of otters within 100-200 km of
shoreline, including offshore habitats and islands out to the 50 m depth contour to estimate the
densities (#/km2) of sea otters and their distances from shore. The general skiff-survey protocol
(Estes 1990) has been used extensively and was recently adopted by the U.S. Fish and Wildlife
Service in its monitoring plan for sea otters in Alaska
(http://alaska.fws.gov/fisheries/mmm/seaotters/pdf/Final%20Alaska%20Sea%20Otter%20Population%20
Monitoring%20Plan%2001JUL2005.pdf.). Locations of all otters will be mapped and distances to
shore recorded. This activity will require 6 person-days at each site.
Stranded Carcass Surveys: We will survey coastlines where sea otter carcasses may be
deposited or accumulate (e.g., at haulout sites). Two-person teams will walk near the high water
line along stretches of accessible beach and record the remains of all sea otters found. The
location and nature (e.g., complete skeleton, partial skeleton, skull only) of the remains will be
recorded using established protocols (Monson et al. 2000). A premolar (or another tooth if the
premolar is not present) will be extracted from each carcass or partial carcass to provide an
estimated age. The estimated age class of the individual (pup, juvenile, adult, or aged adult) also
will be determined in the field based on skeletal or tooth eruption and wear patterns. Tracklines
of areas surveyed will be maintained, from which carcass recovery rates (carcasses/km of shore
surveyed) will be determined. This activity will require 4 person-days at each site.
Prey Availability and Community Structure: We will sample sea otter prey and various
related aspects of benthic community structure at each site. Briefly, this is done by
Estes and Bodkin Research Plan
superimposing a grid over the coastal region to be sampled and using the grid intersections with
shoreline to define the potential sample sites. From these, 35 sites are randomly selected and
GPS coordinates are assigned to each. At each site a team of two SCUBA divers samples the
epibenthic community by randomly placing ¼ m2 quadrats on the sea floor. One of the divers
counts the number of kelps and estimates the percent cover of the common sessile invertebrates
and algae; the other diver counts and collects all of the benthic macroinvertebrates, most of
which are sea urchins, from within the quadrat. Further details of the benthic sampling procedure
are provided by Estes and Duggins (1995). This activity will require 8 person-days per site.
Energy recovery: We will directly observe foraging sea otters using conventional shore based
focal animal observations with high resolution telescopes (50-80x Questar, New Hope, PA) and
binoculars (Doroff and Bodkin 1994). The objective will be to obtain data from 25-50 individual
foraging bouts, consisting of 1-20 dives per bout. We will describe foraging success, prey
species, number and size, and from these data we will calculate the net rate of energy gain by
individual and by site. Data recovery rates will likely vary with sea otter density. At average
densities of about 1 otter/km2, we can measure about 1.5 bouts/hr and thus a field crew of 2
people will be able to observe about 20 bouts/d, or 40 bouts in 2 days. The data recovery rates
will be less where densities are lower. We anticipate that this work will require 6 person-days
per site. Where densities are very low we may establish temporary field camps with a team of
two observers for periods of 1-2 weeks, or we may extend this activity into Phase Two (see
below).
Behavioral response to Killer Whale sounds and visual cues: We will experimentally assess
sea otter vigilance and response to the presence of killer whales by playing recordings of killer
whale calls and blows and by displaying an artificial dorsal fin to individual sea otters. An
observer blind to the type of trial presented will record all behaviors of the focal otters prior to,
during and after playbacks. This work will be conducted under the supervision of Dr. Lance
Barrett-Lennard (see attached letter). The various activities will require 4 person-days per site
and will be coordinated with the energy recovery rate protocol describe above.
PHASE TWO
Health, body condition, and disease assessment: Sea otters will be captured using standard
protocols approved by the Institutional Animal Use and Care Committee of the U.S. Geological
Survey, Alaska Science Center. Our standard capture method involves diver-operated traps and
surface tangle nets--methods we have employed successfully in capturing sea otters elsewhere.
The captured sea otters are immobilized with Fentynal to obtain body measurements and the
various other samples, and the otters will then receive a reversal drug and be released (Monson et
al. 2001). Data and tissues collected will include body length, mass and girth, a premolar for age
determination, blood, swabs, and tissue biopsies to evaluate general health, disease exposure, and
potential genetic bottlenecks.
The sampling procedures and data analyses for health and disease exposure will be done in
accordance with standard protocols that have been established for live sea otter captures
throughout the species range. These were initially developed by veterinarians and health
scientists from the California Department of Fish and Game and UC Davis School of Veterinary
Estes and Bodkin Research Plan
Medicine, and are currently in use in all permitted wild sea otter captures done by the U.S.
Geological Survey, the U.S. Fish and Wildlife Service, and the Alaska SeaLife Center. The
proposed work will be conducted as an integrated part of that larger effort. Dr. Pam Tuomi
(Alaska SeaLife Center) will provide guidance and oversight for these analyses.
We will attempt to sample a minimum of 10-20 otters from each of the 4 sites. Capture rate, and
thus sample sizes will vary with population density. More field time therefore will be required at
locations where densities are low. We anticipate this activity will require a crew of 6 people for
3 days per site where otters are abundant and 2 crews of 5 people for 5 days per site where otters
are rare.
Because similar sampling methods will be employed at all the sites, we expect to be able to
subject geographical patterns to statistically rigorous tests using Analysis of Variance. We
anticipate using locations as treatments and post-hoc treatment comparisons to identify those that
differ significantly from one another. From past experience, we know that the proposed sample
sizes will provide sufficient power to detect variation of the magnitude expected for each of the
metrics described above. Information theoretic approaches (such as AIC) also will be used to
evaluate the relative importance of various sources of variation (e.g., within vs. outside areas of
sea otter decline, east vs. west) in each of the data bases.
E. Timeline and Milestones
The proposed research will be completed in two phases. The initial phase in which we will
sample sea otter density, carcass deposition, prey, and energy recovery will be conducted during
a 16 day cruise in summer 2008. Sampling for sea otter body condition, health and disease will
be completed during a 16 d cruise in 2009. We expect to use the F/V Norseman or a comparable
vessel to support the work.
With a scientific crew of 12 people, the 32 days of requested ship time will provide a total of 382
person days of field time. Assuming 5 days (60 person days) lost for travel and weather, this
leaves 322 person days of actual on-site work time. From the information provided in the
descriptions of work (immediately above) and Table 2 (below), an estimated 292 days of on-site
field time will be required to complete the proposed work. The proposed work will be done in 2
succeeding years (rather than a single long cruise) 1) because the exact locations of the Phase 2
research will depend on results from surveys conducted during Phase 1; 2) somewhat different
personnel and equipment will be needed for Phase 1 and Phase 2 activities; and 3) in order to
provide the latitude to complete the work at any sites in year 2 that could not be sampled in year
1.
September 2008: Complete Phase one data collection
December 2008: Complete sample analysis and data QA/QC
January 2009: Report preliminary findings at Alaska Marine Science Symposium
April 2009: Provide annual report to NPRB
Estes and Bodkin Research Plan
September 2009: Complete Phase two data collection
December 2009: Complete sample analysis and data QA/QC
January 2009: Report findings of project at Alaska Marine Science Symposium
May 2010: Provide final report to NPRB
Research results will be disseminated through a final report to NPRB, and publication in peer
reviewed manuscripts. Findings will be made available to governmental and non-governmental
agencies.
F. Project Management
The project will be managed by the principal investigator, James A. Estes (Alaska Sea Life
Center, Seward, Alaska) and the co-principal Investigator, James L. Bodkin (Alaska Science
Center, US Geological Survey, Anchorage, AK).
James A. Estes is a research scientist with the Department of Interior and currently serves as Sea
Otter Program Manager for the Alaska Sea Life Center. He is also an adjunct professor of
ecology and evolutionary biology at the University of California at Santa Cruz. Work done by
Estes and colleagues provides the foundation for our current understanding of the pattern, cause,
and consequences of the recent sea otter decline in the central/western Aleutian Islands. He
currently manages annual budgets of approximately $1,400,000 that include both congressional
appropriations and extramural funding. The Estes program will bring in-kind contributions of
salary, equipment and supplies from the Alaska SeaLife Center and USGS of approximately
$80,000 and will contribute data from 2 of the 13 sites (Table 1) at no cost to NPRB. Estes,
Bodkin and their associated staffs have collaborated extensively on various research projects
having to do with sea otters and coastal ecosystems in Alaska, California, and Russia. Estes and
colleagues have published several books and >125 peer-reviewed papers (see CV).
James L. Bodkin has been the leader for the Department of Interior sea otter and coastal
ecosystems research in Alaska since 1990. He is responsible for managing science projects in
nearshore marine ecosystems across the north Pacific from California to Russia. He manages
annual budgets of approximately $800,000 that include both congressional appropriations and
funds acquired through competitive process within and external to the Federal government.
Bodkin will bring in-kind contributions of salary, equipment, and supplies from USGG of
approximately $70,000 and will contribute data from five of the 13 sites (Table 1) at no cost to
NPRB (approximate value $24,000). Bodkin has successfully managed and participated in
complex, multi-disciplinary, long-term scientific programs since 1990 and consistently
demonstrated the capacity to meet contractual requirements and professional obligations through
the publication of results in the scientific literature (see CV).
Estes and Bodkin Research Plan
G. Figures and Tables
Figure 1. Phase one sampling locations along the transect across the Pacific to delineate extent, cause,
and constraints to recovery in the SW Alaska sea otter (see Tables 1 and 2 for sampling sites, data
collection protocols, and a summary of the data that are currently available to complete the analysis).
Figure 2. Phase two proposed sampling locations to assess condition, health, and disease through the
capture of individual sea otters in SW Alaska. Red circles represent potential sampling locations, to be
determined following analysis of Phase one data collection. Orange circles represent sites of ongoing or
recent sampling that will provide comparable data without cost to this proposal.
Adak Island
g 0.25m-2
400
Amchitka Island
Estes and Bodkin Research Plan
200
0
-- mid 1980s; before decline (100% K)
-- late 1990s; after decline (~ 5-10% K)
A. Sea urchin biomass density before vs. after sea otter declines at Adak and Amchitka islands.
Magenta-colored percentages indicate estimated sea otter population density relative to
carrying capacity.
35
30
Weight (kg)
25
20
15
Ale utian fem ales, 2004
10
Com mande r Isl. female s, 2006
Ale utian fem ales, 1960 s
Ale utian fem ales, 1993
5
0
5
10
15
20
25
B. Growth curves (mass at age) for female sea otters at various places and times in the Aleutian
archipelago and Commander Islands. Note that growth rate and asymptotic size increase as
abundance is reduced from carrying capacity.
Log (Distance to shore, m)
10
YEAR
1995
2005
5
167m
37m
0
-5
200
100
0
100
200
Count
C. Frequency distributions of distance from shore by sea otters at Adak Island in 1995 and 2005.
Figure 3. Examples of changes in sea otter food availability (A), morphology (B) and behavior (C) with
declining population density in the Aleutian archipelago.
Estes and Bodkin Research Plan
Table 2. Locations and sampling protocols to delineate extent, cause, and constraints to recovery in the
SW Alaska sea otter. Proposed sample locations along a longitudinal transect across the north Pacific
from the Commander Islands, Russia to Prince William Sound, Alaska (see Figure 1 and Table 2). Blue
data protocols will be carried out in 2008. “Population Density”-- includes distribution and distance to
shore; “Carcass Deposition”--the search and recovery of beach cast sea otter carcasses. “Prey
Availability”--direct measures of sea otter prey abundance, prey size, and benthic community structure;
“Energy Recovery”--visual observations of foraging sea otters. The health/disease data protocol includes
the capture of live animals for assessment of condition, health and disease and is to be conducted in 2009
at three sites dependent on results of the 2008 data collection. Locations with grey shading--data
available from ongoing or recent research at no cost to NPRB. Locations indicated by X indicate where
concurrent or recent data are available using appropriate protocols.
Population
Density
PHASE 1 (2008)
Carcass
Prey
Deposition Availability
1. Bering Island
X
X
X
2. Central Aleutians
X
X
X
Location
Energy
Recovery
PHASE 2 (2009)
Health, Disease,
Body Condition
X
X
X
3. Fox Islands
4. Sanak Reefs
5. Pavlov Bat
6. Shumigam Islands
X
7. Chignik
8. Semidi Islands
X
9. Katmai
X
10. Kodiak
X
11. Kamishak Bay
X
12. Kachamak Bay
X
13. Prince William
Sound
X
X
X
X
X
X
X
X
X
X
H. References
Burn, D.M, A.M. Doroff, and M.T. Tinker. 2003. Carrying capacity and pre-decline abundance
of sea otters (Enyhdra lutris kenyoni) in the Aleutian Islands. Northwestern Naturalist 84: 145148.
Doroff, A.M. and J.L. Bodkin. 1994. Sea otter foraging behavior and hydrocarbon levels in
prey. in T. Loughlin, editor. Marine mammals and the Exxon Valdez. Academic Press. San
Diego, CA pages 193-208.
Estes, J.A. (1990) Growth and equilibrium in sea otter populations. Journal of Animal Ecology,
59: 385-400.
Estes and Bodkin Research Plan
Estes, J.A., M.T. Tinker, T.M. Williams, and D.F. Doak. 1998. Killer whale predation on sea
otters linking oceanic and nearshore ecosystems. Science 282: 473-476.
Estes, J.A., E.M. Danner, D.F. Doak, B. Konar, A.M. Springer, P.D. Steinberg, M.T. Tinker, and
T.M. Williams. 2004. Complex trophic interactions in kelp forest ecosystems. Bulletin of Marine
Science 74: 621-638.
Estes, J.A., Tinker, M.T., Doroff, A.M. & Burn D.M. (2005) Continuing sea otter population
declines in the central and western Aleutian archipelago. Marine Mammal Science, 21: 169-172.
Estes, J.A. & Duggins, D.O. (1995) Sea otters and kelp forests in Alaska: generality and
variation in a community ecological paradigm. Ecological Monographs 65: 75-100.
Hanni, K.D., J.A.K. Mazet, F.M.D. Gulland, J.A. Estes, M. Staedler, M.J. Murray, and D.A.
Jessup. 2003. Clinical pathological values and assessment of pathogen exposure in southern and
Alaskan sea otters. Journal of Wildlife Disease 39:837-850.
Laidre, K.L., J. A. Estes, M. T. Tinker, J. Bodkin, D. Monson, and K. Schneider. 2006. Patterns
of growth and body condition in sea otters from the Aleutian archipelago before and after the
recent population decline. Journal of Animal Ecology 75: 978-989.
Monson, D.H., D.F. Doak, B.E. Ballachey, A. Johnson, and J.L. Bodkin. 2000. Long-term
impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality
patterns. Proceedings National Academy of Sciences, USA.97(12):6562-6567.
Monson, D. H., McCormik, C. & Ballachey, B.E. (2001) Chemical anesthesia of northern sea
otters (Enhydra lutris): Results from past field studies. Journal of Zoology and Wildlife Medicine
32:181-189.
Reese, S.L., J.A. Estes, and W.M. Jarman. Organochlorine contaminants in coastal marine
ecosystems of the Aleutian archipelago and southeast Alaska: source and transport mode inferred
from spatial analyses of blue mussels (Mytilus trossulus). Ecological Applications (in review).
Williams, T.M., J.A. Estes, D.F. Doak, and A.M. Springer. 2004. Killer appetites: assessing the
role of predators in ecological communities. Ecology 85: 3373-3384.
NPRB BUDGET SUMMARY FORM - MULTIPLE ORGANIZATIONS
PROJECT TITLE:
PRINCIPAL INVESTIGATOR(S):
FUNDING SOURCE
NPRB Funding
Sea otter decline
James Estes (ASLC); James Estes (USGS-Western Ecological Research
Center); James Bodkin (Co-PI, USGS Alaska Science Center);
YEAR 1
YEAR 2
YEAR 3
TOTAL
145,615
153,557
635
Other Support
TOTAL
Cost Categories
1. Personnel Salaries
299,807
263,980
145,615
153,557
635
Annual cost
category
breakdowns will
be requested for
other support
only if project is
funded
563,787
NPRB
NPRB
NPRB
NPRB
Match/In kind
Year 1
Year 2
Year 3
TOTAL
TOTAL (all years)
2,500
2,500
0
5,000
159,772
625
625
0
1,250
39,942
15,460
15,460
500
31,420
8,960
4. Equipment
0
0
0
0
0
5. Supplies
0
4,250
0
4,250
0
96,000
96,000
0
192,000
0
0
2,000
0
2,000
0
114,585
120,835
500
235,920
208,674
31,030
32,722
135
63,887
55,306
145,615
153,557
635
299,807
263,980
2. Personnel Fringe Benefits
3. Travel (include 1 trip to review
mtg in Anchorage each year plus for
the year following project conclusion)
6. Contractual/Consultants
7. Other (Include $2000 for education
and outreach)
Total Direct Costs
Indirect Costs
TOTAL PROJECT COSTS
James Allen Estes
U.S. Geological Survey - Biological Resources Division
100 Shaffer Road; Santa Cruz, CA 95060
Phone: 831-459-2820; Email: jestes@ucsc.edu
Degrees:
B.A.
M.S.
Ph.D.
University of Minnesota
Washington State University
University of Arizona
1967
1969
1974
Zoology
Zoology
Biological Sciences/Statistics
Appointments:
Supervisory Wildlife Biologist, Western Ecological Research Center, Biological Resources Division, US
Geological Survey (position previously administered by National Biological Service [NBS] and Fish and
Wildlife Service), Santa Cruz, CA, 1978-Present
Adjunct Professor in Biology, Marine Sciences, and Environmental Studies, University of California at Santa
Cruz, 1979-Present
Research Biologist, U.S. Fish and Wildlife Service, National Fish and Wildlife Lab, Anchorage, AK, 1975-1978
Teaching/Research Assistant, Dept. of Biology, University of Arizona, Tucson, AZ, 1972-1974
Research Associate, Department of Biology, University of Arizona, Tucson, AZ, 1970-1972
Teaching Assistant, Department of Zoology, Washington State University, Pullman, WA, 1967-1970
5 Relevant Publications:
• Estes, J.A., and J.F. Palmisano. 1974. Sea otters: their role in structuring nearshore communities. Science
185: 1058-1060.
• Estes, J.A., and P.D. Steinberg. 1988. Predation, herbivory and kelp evolution. Paleobiology 14: 19-36.
• Estes, J.A, and D.O. Duggins. 1995. Sea otters and kelp forests in Alaska: generality and variation in a
community ecological paradigm. Ecological Monographs 65: 75-100.
• Estes, J.A., M.T. Tinker, T.M. Williams, and D.F. Doak. 1998. Killer whale predation on sea otters linking
coastal with oceanic ecosystems. Science 282: 473-476.
• Laidre, K.L., J.A. Estes, M.T. Tinker, J. Bodkin, D. Monson, and K. Schneider. 2006. Patterns of growth
and body condition in sea otters from the Aleutian archipelago before and after the recent population
decline. Journal of Animal Ecology 75: 978-989.
5 Other Publications:
• Simenstad, C.A., J.A. Estes, and K.W. Kenyon. 1978. Aleuts, sea otters, and alternate stable state
communities. Science 200: 403-411.
• Duggins, D.O., C.A. Simenstad, and J.A. Estes. 1989. Magnification of secondary production by kelp
detritus in coastal marine ecosystems. Science 245: 170-173.
• Steinberg, P.D., J.A. Estes, and F.C. Winter. 1995. Evolutionary consequences of food chain length in kelp
forest communities. Proc. Natl. Acad. Sci. 92: 8145-8148.
• Jackson, J.B.C., et al. 2001. Historical overfishing and the recent collapse of coastal ecosystems. Science
293: 629-637.
• Springer, A.M. et al. 2003. Sequential megafaunal collapse in the North Pacific Ocean: an ongoing legacy of
industrial whaling? PNAS 100:12223-12228.
Synergistic Activities:
Editor, Marine Mammal Science; Board of Editors, Frontiers of Ecology and the Environment,
Marine Ecology Progress Series. Pew Fellow in Marine Conservation. National Research Council
Study Committee—Steller sea lion. Southern sea otter Recovery Team and Recovery Implementation
Team; NCEAS Science Advisory Board. Fellow, California Academy of Sciences.
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Co-authors and Collaborators:
J. Ames, California Dept. of Fish & Game; S. Andelman, NCEAS/UC Santa Barbara; R.G. Anthony;
US Geological Survey; J. Berger, Wildlife Conservation Society; W.H. Berger, Scripps Institution of
Oceanography; K.A. Bjorndal, University of Florida; J.L. Bodkin, US Geological Survey; L.W.
Botsford, UC Davis; B.J. Bourque, Bates Univ.; W.D. Bowen, Bedford Institute of Oceanography; R.
Bradbury, Australian National University; D. Burn, US Fish & Wildlife Service; M. Carr, UC Santa
Cruz; P.A. Conrad, UC Davis; R. Cooke, Smithsonian Tropical Research Institute; D. Corbett, US
Fish & Wildlife Service; K. Crooks, Colorado State Univ.; E.M. Danner, National Marine Fisheries
Service; D.F, Doak, UC Santa Cruz; E. Dodd, CA Dept. of Fish & Game; A.M. Doroff, US Fish &
Wildlife Service; J.M. Erlandson, Univ. of Oregon; T.J. Evans, US Fish & Wildlife Service; K.A.
Forney, NMFS; I.A. Gardner, UC Davis; T.S. Gelatt, NMFS; L.R. Gerber, NCEAS/UC Santa
Barbara; G.H. Golet, The Nature Conservancy; M.H. Graham, Moss Landing Marine Laboratories;
F.M.D. Gulland, The Marine Mammal Center; K.D. Hanni, Monterey Bay Aquarium; B. Hatfield, US
Geological Survey R. Holt, Univ. of Florida; T.P. Hughes, James Cook Univ.; D.B. Irons, US Fish &
Wildlife Service; J.B.C. Jackson, Scripps Institution of Oceanography; R.J. Jameson, retired; D.A.
Jessup, CA Dept. of Fish & Game; S. Kidwell, Univ. of Chicago; M.X. Kirby, NCEAS/UC Santa
Barbara; B. Konar, Univ. of Alaska Fairbanks; D.J. Kushner, Channel Islands National Park; K.
Laidre, UC Santa Cruz; C.B. Lange, Scripps Institution of Oceanography; J. Largier, Scripps
Institution of Oceanography; H.S. Lenihan, University of North Carolina Chapel Hill; L.J.
Lowenstine, UC Davis; J. Lubchenco, Oregon State Univ.; B.E. Lyon, UC Santa Cruz; C. Martinez
del Rio, Univ. of Wyoming; J.K. Mazet, UC Davis; M.A. Miller, UC Davis; D. Monson, US
Geological Survey; M.J. Murray, Monterey Bay Aquarium; J. Neigel, Univ. of Louisiana; A.
Packham, UC Davis; M.J. Paddack, Rosenstiel School of Marine & Atmospheric Science; J.M.
Pandolfi, Smithsonian Institution; C.H. Peterson, Univ. of North Carolina Chapel Hill; K. Ralls,
Smithsonian National Zoological Park; A.J. Read, Center for Marine Conservation; D.C. Reed, UC
Santa Barbara; M.L. Riedman, Monterey Bay Aquarium; J.A. Schmutz, US Geological Survey; S.C.
Schroeter, UC Santa Barbara; D.B. Siniff, Univ. of Minnesota; M.E. Soulé, UC Santa Cruz emeritus;
A.M. Springer, Univ. of Alaska Fairbanks; M. Staedler, Monterey Bay Aquarium; P.D. Steinberg,
Univ. of New South Wales; R.S. Steneck, Univ. of Maine; M.J. Tegner, deceased; M.T. Tinker, UC
Santa Cruz; G.B. van Vliet, Alaska Dept. of Environmental Conservation; R. Warner, UC Santa
Barbara; J. Watt, Locherby Fisheries Trust; T.M. Williams, UC Santa Cruz
Names and current locations of graduate students from the past five years:
Matthew Edwards, Ph.D. 2001. Assistant Professor, San Diego State University
Shauna Reisewitz, M.S. 2002. High School Teacher, Santa Cruz, CA
M. Timothy Tinker. Ph.D. 2004. Postdoc, UC Santa Cruz
Alisha Kage, M.S. 2004. US Geological Survey, Santa Cruz, CA
Gena Bentall, M.S. 2005. Alaska SeaLife Center, Seward, AK
Eric Danner, Ph.D. 2006. National Marine Fisheries Service, Santa Cruz, CA
Names and current locations of postdocs from the past five years:
Jon Watt, Locherby Fisheries Trust, Scotland
Kristin Laidre, Copenhagen, Denmark
M. Timothy Tinker, UC Santa Cruz
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Resume
James L. Bodkin
Project Leader, Research Wildlife Biologist
U.S. Geological Survey, Alaska Science Center
1011 East Tudor Road
Anchorage, Alaska 99503, USA
Phone: 907-786-3550
Fax: 907-786-3636
E-mail: James_Bodkin@usgs.gov
Education
1985 - MS, California Polytechnic State University, San Luis Obispo, CA. (Wildlife Biology)
1976 - BS, Long Beach State University (Biology), Long Beach, CA
Current Activities
I lead the Alaska sea otter research project and the coastal ecosystems team of the Alaska Science
Center, US Geological Survey. Research is organized into three programs: 1) Sea otter
population assessment, 2) Processes structuring coastal ecosystems and, 3) Effects and status of
recovery of the nearshore ecosystem from the 1989 Exxon Valdez oil spill in Prince William
Sound. Each of these programs consists of several independent research projects. I supervise and
manage all activities associated with this complex and diverse array of research projects internal
to the Alaska Science Center and collaborate with at least 14 agencies, academic or private
institutions on cooperative, multi-disciplinary projects. I lead a scientific team of six, and
manage annual budgets of about $700,000 that include USGS and cyclic funds. I also lead the
Coastal Marine Ecosystem Team, a multi-disciplinary research effort investigating coastal
ecosystems in the North Pacific. Coastal Marine Ecosystem Team research programs, in addition
to sea otters include; benthic habitat classification, biological and physical oceanography,
seabirds and other marine mammals, marine invertebrates, and marine fishes.
Relevant Publications
Iverson, S.J., A.M. Springer, and J.L. Bodkin. In press. Harbor seals, sea lions, and sea otters,
fundamental life history characteristics: similarities, differences, and gradations. In Robert Spies
(ed.). Ecosystem change in the northern Gulf of Alaska.
Bodkin, J.L., G.G. Esslinger and D.H. Monson. 2004. Foraging depths of sea otters and
implications to coastal marine communities. Marine Mammal Science 20(2):305-321.
Bodkin, J.L., B.E. Ballachey, T.A. Dean, A.K. Fukuyama, S.C. Jewett, L.M. McDonald,
D.H.Monson, C.E. O’Clair and G.R. VanBlaricom. 2002. Sea otter population status and the
process of recovery from the Exxon Valdez oil spill. Marine Ecology Progress Series. 241:237253.
Estes, J.A. and J.L. Bodkin. 2002. Marine Otters. In W.F. Perrin, B. Wursig,, J.G.M. Thewissen
and C.R. Crumly (eds) Encyclopedia of Marine Mammals. Academic Press 843-858.
Bodkin, J.L. 2001. Marine Mammals: Sea otters. Pages 2614-2621. in Steele, J. S.Thorpe and
K. Turekian (eds.) Encyclopedia of Ocean Sciences. Academic Press, London UK.
1
Other Selected Publications
Bodkin, J.L., A.M. Burdin and D.A. Ryzanov. 2000. Age and sex specific mortality and
population structure in sea otters. Marine Mammal Science 16(1):201-219.
Monson, D.H., D.F. Doak, B.E. Ballachey, A. Johnson, and J.L. Bodkin. 2000. Long-term
impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality
patterns. Proceedings National Academy of Sciences, USA 97(12):6562-6567.
Bodkin, J.L., B.E. Ballachey, M.A. Cronin and K.T. Scribner. 1999. Population demographics
and genetic diversity in remnant and re-established populations of sea otters. Conservation
Biology 13(6):1278-1385.
Doroff, A.M. and J.L. Bodkin. 1994. Sea otter foraging behavior and hydrocarbon levels in
prey. in T. Loughlin, editor. Marine mammals and the Exxon Valdez. Academic Press. San
Diego, CA pages 193-208.
Collaborators
Ballachey, Brenda, Alaska Science Center, Anchorage, AK , 403-288-9184
Burn, Douglas, US Fish and Wildlife Service, Anchorage, AK, 907-786-3807
Dean, Thomas, Coastal Resources Associates, San Diego, CA, 760-603-0612
Doroff, Angela, US Fish and Wildlife Service, Anchorage, AK, 907-786-3803
Esler, Dan, Simon Fraser University, Victoria, B.C. 604-940-4652
Estes, James, University of California, Santa Cruz, CA, 831-459-2820
Howlin, Shay, West Ecosystems Technology, Cheyenne, WY, 307-634-1756
Irons, David, US Fish and Wildlife Service, Anchorage, AK 907-786-3653
McDonald, Lyman, Western Ecosystems Technology, Cheyenne, WY, 307-634-1756
Snyder, Paul, Purdue University, West Lafayette, IN, 765-494-9676
Staedler, Michelle, Monterey Bay Aquarium, Monterey, CA, 831-648-4976
Tinker, Tim, University of California, Santa Cruz, CA, 831-459-2357
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