Sea Otter Research and Conservation Symposium
Sea Otter Research and Conservation Symposium
Thursday, April 1: 12:30pm to 4:15pm PDT Friday, April 2: 9am to 1:15pm PDT
Meeting hosts Seattle Aquarium and Defenders of Wildlife
Zoom coordinators and meeting facilitators Shawn Larson (Seattle Aquarium), Andy Johnson (Defenders of Wildlife), Michelle Staedler (UC Santa Cruz), Becky Bingham (Seattle Aquarium), Monica LeFlore (Defenders of Wildlife) Thursday, April 1, 2021
Seattle Aquarium 12:30pm Welcome and acknowledgments Defenders of Wildlife
SESSION ONE: Demographics Moderated by Michelle Staedler
12:40pm Joe Tomoleoni Southern Sea Otter Population Status Update
12:45pm Julie Yee San Nicolas Southern Sea Otter Research Update
12:50pm Colleen Young Southern Sea Otter Stranding Update
1pm Ron Eby Update on the Otters at Elkhorn Slough
Status, Trends and Equilibrium Abundance Estimates of the 1:05pm Jessie Hale Translocated Sea Otter Population in Washington State
1:15pm Teal Waterstrat Washington Northern Sea Otter Population Status and Stranding
Sea Otter Population Surveys and Benthic Sampling in the 1:25pm Paul Schuette Western Aleutians
Diffusion Modeling Reveals Effects of Multiple Release Sites and 1:30pm Joseph Eisaguirre Human Activity on A Recolonizing Apex Predator
Life History (LHX2) Tags in Kachemak Bay, Alaska: Pilot Project 1:35pm Caroline Cummings Update
1:45pm Q & A
1:50pm Break
SESSION TWO: Conservation, management and outreach I Moderated by Andy Johnson
1:55pm Lilian Carswell Southern Sea Otter Management Update
2:05pm Dan Esler USGS Sea Otter Research and Monitoring in Alaska
Changes to Preparation for Responding to 2:15pm Don Noviello Oil Injured Sea Otters
Evaluating the Feasibility of Sea Otter Restoration in Oregon: 2:25pm John Goodell Studies, Plans, and Updates
2:35pm Nicole Duplaix IUCN/SSC Otter Specialist Group Update
2:40pm Andy Johnson Defenders of Sea Otters!
2:45pm Q & A
2:50pm Break
Sea Otter Research and Conservation Symposium 2 SESSION THREE: Conservation, management, and outreach II Moderated by Tim Tinker
2:55pm Heather Barrett Sea Otter Savvy and the Cost of Disturbance
The Economic Value of Sea Otters and Recreational Tourism in a 3:05pm Jessica Fujii California Estuary
Examining Potential Conflict Between Sea Otters and the 3:15pm Andre Boustany Dungeness Crab Fishery in California
Behavioral Responses Across a Mosaic of Ecosystem States 3:25pm Josh Smith Restructure a Sea Otter-Urchin Trophic Cascade
Population Impacts of Domoic Acid Exposure in Southern Sea 3:35pm Megan Moriarty Otters: An Increasing Threat in a Changing Climate
A Summary of Sea Otter Modeling Efforts to Inform Conservation 3:45pm Tim Tinker from California to Oregon to Haida Gwaii
4pm Q & A
4:05pm Announcements, appreciations, wrap-up
4:15pm Day 1 adjourned
Friday, April 2, 2021
Seattle Aquarium 9am Welcome and acknowledgments Defenders of Wildlife
SESSION FOUR: Health Moderated by Mike Murray
Kathy Burek Causes of Mortality of Northern Sea Otters (Enhydra lutris kenyoni) 9:05am Huntington in Alaska from 2002 to 2012
9:10am Greg Frankfurter Sea Otter Rehabilitation in the Puget Sound
Bacterial Taxa Associated with Nasopulmonary Mites 9:15am Risa Pesapane (Acari: Halarachnidae) Including Streptococcus phocae in Marine Mammals
Suspected Ovarian Granulosa Cell Tumor in an Adult Female 9:25am Angelina Reed Southern Sea Otter (Enhydra lutris nereis)
Southern Sea Otter Thermal Function and Morphology Across 9:30am Kate Riordan Ontogeny
Investigating the Presence and Trophic Transfer of Microplastics in 9:40am Jennifer VanBrocklin Ex- and In-Situ Sea Otters using Scat and Diet Analysis
Sea Otter Research and Conservation Symposium 3 9:45am Q & A
9:50am Break
SESSION FIVE: Genetics Moderated by Shawn Larson
Range-wide Genomic Sampling Illuminates Sea Otter Population 9:55am Annabel Beichman Structure and Consequences of Fur Trade Exploitation
Investigating Relationships Between Genetics and Causes of 10:05am Nicole Hallie Carter Mortality in Southern Sea Otters (Enhydra lutris nereis)
Physical Disturbance by Recovering Sea Otter Populations 10:15am Erin Foster Increases Eelgrass Genetic Diversity
Investigation of Antimicrobial Resistance Gene Patterns Among 10:20am Peter Sebastian Vibrio spp. in Sea Otters and Marine Mussels
Effects of Limited Dispersal by Sea Otters (Enhydra lutris) on 10:25am Daniel Monson Population Dynamics: Relevance to the Threatened Southwest Alaska Distinct Population Segment
10:35am Shawn Larson Seattle Aquarium’s Sea Otter Research Program
Archaeological Mitogenomes Illuminate the Historical Ecology of 10:40am Hannah Wellman Oregon Sea Otters (Enhydra lutris)
10:50am Q & A
10:55am Break
SESSION SIX: Ecology I Moderated by Karl Mayer
Historical Ecology of Sea Otters from Alaska, Oregon 11am Emma Elliott Smith and California
Sea Otter Impacts to Seagrass Communities Across the Northeast 11:05am Joseph Jackson Pacific
Changes in Kelp Canopy Cover Associated with Sea Otter Recovery 11:10am Tom Bell in the Northeast Pacific
Monitoring the Salt Marsh Habitat Use and Foraging Habits of 11:15am Madeline Sanchez the Recovering Southern Sea Otter (Enhydra lutris nereis) in a Recolonized Ecosystem
11:20am Nicole LaRoche Sea Otter Diet Composition in Southern Southeast Alaska
Flexing Their Mussels: Sea Otter Diet Shifts in Response to Mussel 11:25am James Bodkin Abundance
Combining Contemporary Models and Aerial 11:30am Jamie Womble Photographic Surveys to Monitor Sea Otters in Glacier Bay National Park, Alaska
Sea Otter Research and Conservation Symposium 4 Dietary Patterns and Energy Intake Rates of Sea Otters 11:40am George Esslinger Recolonizing Glacier Bay
Sea Otter Carrying Capacity in a Soft- and Mixed-Sediment 11:50am Randall Davis Benthic Habitat
Noon Mike Kenner Tribute to Glenn VanBlaricom
12:05pm Q & A
12:10pm Break
SESSION SEVEN: Ecology II Moderated by Lilian Carswell
Sea Otter-Orca Interaction Geodatabase: A New Tool for 12:15pm Bethany Walter Researchers and Managers
12:20pm Carter Johnson Fast Kelp-Crab-Handling in Washington’s Sea Otter Population
Investigations of Southern Sea Otter Foraging Ecology at the 12:25pm Sophia Lyon Northern Range Extent
12:35pm Chris Law Tool Use Benefits in Southern Sea Otters
North Pacific Warming Shifts the Juvenile Range of a Marine Apex 12:45pm Sal Jorgensen Predator
Proposed Research: Kelp Forest Complexity, Connectivity and 12:55pm Zachary Randell Resilience with and Without Keystone Predators Along the Olympic Coast
1:05pm Q & A
1:10pm Announcements, appreciations, farewells
1:15pm Day 2 adjourned
Sea Otter Research and Conservation Symposium 5 SESSION ONE: Demographics
Southern Sea Otter Population Status Update Joe Tomoleoni, U.S. Geological Survey [email protected] This talk provides a summary of the results from our most recent (2019) range-wide census of the southern sea otter population and shares plans for future counts.
San Nicolas Southern Sea Otter Research Update Julie Yee, U.S. Geological Survey [email protected] This talk gives an overview of research on the southern sea otter subpopulation at San Nicolas Island, CA, including our latest information on their size, distribution and forage diet.
Southern Sea Otter Stranding Update Colleen Young, California Department of Fish and Wildlife [email protected] Stranded sea otters have been systematically collected and examined in California since 1968. The sea otter stranding network is a collaborative effort of many organizations and has resulted in >9,000 recorded stranded sea otters. A summary of strandings, including demographic and geographic information, causes of strandings, and other interesting trends from 2019 and 2020 will be presented. These two years provide a fascinating juxtaposition, with 427 stranded sea otters in 2019, which was consistent with the average of the previous five years (2014–2018; average = 427.6), and 277 stranded sea otters in 2020.
Update on the Sea Otters at Elkhorn Slough Ron Eby, Elkhorn Slough National Estuarine Research Reserve [email protected] I’ll share historical otter counts since 1984 from USGS and Elkhorn Slough Safari as well as from the Elkhorn Slough Otter Project (2013–2016) and ongoing observations by the Reserve Otter Monitoring Project. The disappearance of the North Harbor otter raft in September of 2019 and other changes in otter distribution. The value of monitoring at least twice a month and the methods used might be applicable to other areas.
Sea Otter Research and Conservation Symposium 6 Status, Trends and Equilibrium Abundance Estimates of the Translocated Sea Otter Population in Washington State Jessie Hale, University of Washington [email protected] I will update our research on sea otter population dynamics in Washington state that was recently submitted for publication. We compile available survey data for sea otters in Washington state since their translocation (1977–2019) and fit a Bayesian state-space model to estimate past and current abundance and equilibrium abundance at multiple spatial scales. We then use forward projections of population dynamics to explore potential scenarios of range recolonization and as the basis of a sensitivity analysis to evaluate the relative influence of movement behavior, frontal wave speed, intrinsic growth and equilibrium density on future population recovery potential.
Washington Northern Sea Otter Population Status and Stranding Teal Waterstrat, U.S. Fish and Wildlife Service [email protected] This talk will provide an overview of abundance and distribution of northern sea otters south of British Columbia and a summary of stranding network observations and causes of mortality.
Sea Otter Population Surveys and Benthic Sampling in the Western Aleutians Paul Schuette, U.S. Fish and Wildlife Service [email protected] The southwest stock of the northern sea otter was listed as Threatened under the Endangered Species Act in 2005 following a dramatic decline in the population. In the western Aleutian Islands, skiff-based sea otter population surveys and scuba-based benthic sampling methods have documented trends in the sea otter population and ecosystem-level changes. Scientists at U.S. Fish & Wildlife Service are collaborating with U.S. Geological Survey in summer 2021 to conduct the next round of sea otter population surveys and scuba-based benthic surveys to extend this rich legacy of data. Additional data collection techniques will be added to account for sea otter detection probability and to explore spatial variation in abundance around islands.
Sea Otter Research and Conservation Symposium 7 Diffusion Modeling Reveals Effects of Multiple Release Sites and Human Activity on a Recolonizing Apex Predator Joseph Eisaguirre, U.S. Fish and Wildlife Service [email protected] In Southeast Alaska, reintroduction of 413 sea otters in the late 1960s initiated the growth and spread of a population that now exceeds 25,000. Periodic aerial surveys in the region provide a time series of spatially-explicit data to investigate factors influencing this successful and ongoing recovery. We integrated an ecological diffusion model into a Bayesian hierarchical framework to estimate process parameters from the survey data. This provided updated estimates of abundance, intrinsic growth and carrying capacity, and revealed some of the factors influencing the success of this recolonization, including how protected areas have affected the movement and density-dependent regulation of the population.
Life History (LHX2) Tags in Kachemak Bay, Alaska: Pilot Project Update Caroline Cummings, U.S. Fish and Wildlife Service [email protected] In 2019, USFWS deployed 20 LHX2 tags in adult female sea otters in Kachemak Bay. This project was conceptualized as a proof of concept before deployment of these tags in the listed Southwest stock located in the remote Aleutian management units. To date, 5 LHX2 tags have been released from animals, showing successful transmissions of end-of-life data. Based on temperature, activity and light sensor data, three mortality events were traumatic deaths, one was an unknown cause and one was a confirmed hunter harvest. Additionally, we have successfully confirmed reproductive events recorded on the tags with visual observations. Surveys in Kachemak Bay will conclude this spring, and we aim to deploy these tags in Amchitka or Adak next.
Sea Otter Research and Conservation Symposium 8 SESSION TWO: Conservation, Management, and Outreach I
Southern Sea Otter Management Update Lilian Carswell, Fish and Wildlife Service/University of California, Santa Cruz [email protected] I will present updates on the Southern Sea Otter Status Assessment, a federal feasibility analysis on sea otter reintroduction mandated by Congress in the explanatory statement for the 2021 Appropriations Act, and other matters pertaining to sea otter management.
USGS Sea Otter Research and Monitoring in Alaska Dan Esler, U.S. Geological Survey [email protected] USGS-ASC is engaged in a variety of sea otter research and monitoring activities occurring across the Alaska range of sea otters. Our work is designed to understand factors that influence sea otter population status, to elucidate the roles that sea otters play in a variety of nearshore systems, and to provide conservation-relevant information to managers of sea otters and their habitats. In this presentation, we provide a broad overview of the work that we and our collaborators (National Park Service, U.S. Fish and Wildlife Service, University of Alaska, Alaska Pacific University, NOAA, BOEM, USGS-WERC) conduct on sea otters in Alaska.
Changes to Preparation for Responding to Oil Injured Sea Otters Don Noviello, Washington Department of Fish and Wildlife [email protected]
For many years there has been a cooperative agreement between Northwest Zoos and Aquariums and the Washington State Department of Fish and Wildlife to respond to oil- injured sea otters during future oil spills. Recent regulatory changes by the Department of Ecology are being enacted to require regulated oil-handling facilities to more completely identify and contract the equipment and personnel that will be needed to implement oiled wildlife response plans as described in the Northwest Area Contingency Plan. This presentation will describe the current situation, describe some potential ways forward and solicit input on how this could best be done.
Sea Otter Research and Conservation Symposium 9 Evaluating the Feasibility of Sea Otter Restoration in Oregon: Studies, Plans, and Updates John Goodell, Elakha Alliance [email protected] The Elakha Alliance is a nonprofit organization dedicated to pursuing the reintroduction of sea otters to the Oregon coast. In 2020, we launched a third-party feasibility study to evaluate a prospective reintroduction. The completed document will be released by the late summer of 2021 and will analyze a broad suite of considerations including population models, habitat suitability, logistics, source populations, release locations, legal dimensions and stakeholder perspectives. Evaluations will also include a rigorous economic assessment of expected positive or negative impacts to varied industries and interests. We will provide an update of these investigations and review developing challenges and opportunities.
Otter Specialist Group Update Nicole Duplaix, IUCN/SSC Otter Specialist Group [email protected] The members of the Otter Specialist Group focus on developing otter conservation programs for the 13 species of otters around the world. This talk will provide a quick update on the Otter Specialist Group’s goals, conservation planning, and activities for the next four years.
Defenders of Sea Otters! Andy Johnson, Defenders of Wildlife [email protected] Defenders of Wildlife has committed new resources toward the conservation of sea otters. This talk will highlight Defenders’ Sea Otter Program Plan elements, including areas of emphasis and effort by our California, Northwest and Alaska programs through 2021. Defenders hopes to add value within all active campaigns to study, protect and restore sea otters throughout their range.
Sea Otter Research and Conservation Symposium 10 SESSION THREE: Conservation, Management, and Outreach II
Sea Otter Savvy and the Cost of Disturbance Heather Barrett, Sea Otter Savvy [email protected] This presentation will provide a brief Sea Otter Savvy program update and share results from the updated energetic cost disturbance model.
The Economic Value of Sea Otters and Recreational Tourism in a California Estuary Jessica Fujii, Monterey Bay Aquarium [email protected] We surveyed visitors to Elkhorn Slough to examine the economic effect recreational activities can have on a local region and determine what role the presence of sea otters has on the value placed on the visit and the area’s preservation. We asked visitors to rank attributes related to their trip and measured the perceived value of the estuary and sea otters to visitors as their willingness to pay a hypothetical fee for access that would go toward protection and restoration. We show that recreational visitors contribute to local economies and sea otters play a role in what visitors value about their visit.
Examining Potential Conflict Between Sea Otters and the Dungeness Crab Fishery in California Andre Boustany, Monterey Bay Aquarium [email protected] We examined sea otter population growth in relation to Dungeness crab catch using landing receipts since the early 1980s. We found Dungeness crab landings and fishing success increased across all ports. In the most recent decade, we observed slower growth in fishing success in northern ports where otters were absent, relative to southern ports where sea otters are present. In ports where otters were present, fishing success was positively correlated with otter population size over time. Further, an extensive dataset of 83,000 sea otter foraging dives identified Dungeness crab to be less than 2% of the total diet.
Sea Otter Research and Conservation Symposium 11 Behavioral Responses Across a Mosaic of Ecosystem States Restructure a Sea Otter-Urchin Trophic Cascade Josh Smith, University of California, Santa Cruz [email protected] For this presentation, I will be sharing results from our recent publication on sea otter responses to a sea urchin outbreak. In 2014, a dramatic sea urchin outbreak shifted a once-expansive kelp forest along the Monterey Peninsula, CA, USA, to a patchy mosaic of remnant kelp forests interspersed with patches of sea urchin barrens. We show that this mosaic of adjacent alternative ecosystem states led to an increase in the number of sea otters (Enhydra lutris nereis) specializing on urchin prey, a population-level increase in urchin consumption, and an increase in sea otter survivorship. We further show that the spatial distribution of sea otter foraging efforts for urchins was predicted by the distribution of energetically profitable prey.
Population Impacts of Domoic Acid Exposure in Southern Sea Otters: An Increasing Threat in a Changing Climate Megan Moriarty, University of California, Davis/California Department of Fish and Wildlife [email protected] Harmful algal blooms can have profound detrimental effects on individual marine mammals, yet population-level impacts of biotoxins are not well characterized. Southern sea otters face many environmental hazards, including domoic acid (DA), which causes neurological and cardiovascular disease. We evaluate the impact of future DA exposure on population viability using an integrated population model, which was modified to allow for DA exposure effects on cause-specific hazards of DA toxicosis and cardiomyopathy. In a series of alternative scenarios, we investigate how increased frequency and severity of future DA events (as might be expected with climate change) translated into changes in abundance of otters in 50 years relative to baseline.
A Summary of Sea Otter Modeling Efforts to Inform Conservation from California to Oregon to Haida Gwaii Tim Tinker, University of California, Santa Cruz/Nhydra [email protected] Years of field research have generated an unparalleled set of data on sea otter ecology, now being harnessed to parameterize integrative models addressing key conservation concerns. I provide a summary of three models tailored to conservation challenges in
Sea Otter Research and Conservation Symposium 12 different regions: 1) the Integrated Population Model (IPM) for southern sea otters was developed to investigate potential management actions and assess the population impacts of multiple competing threats; 2) the Oregon Sea Otter Population model (ORSO) is used to assess recovery potential and ecological/economic impacts of sea otters in Oregon; 3) the Haida Gwaii sea otter model helps communities anticipate effects of sea otter recovery on food security, and evaluate management options.
SESSION FOUR: Health
Causes of Mortality of Northern Sea Otters (Enhydra lutris kenyoni) in Alaska from 2002 to 2012 Kathy Burek Huntington, Alaska Veterinary Pathology Services [email protected] We want to announce that this paper was published in 2021. We examined 780 northern sea otters from 2002 to 2012 to evaluate the causes of death (COD). Forty-four percent of the fresh dead otters (n = 144) were determined to have died of systemic streptococcosis (“Strep syndrome”). Other CODS included neurologic (10%), nutritional (7%), cardiovascular (7%), and gastrointestinal (6%) disease, trauma (8%), septicemia (3%), and neoplasia (3%). Five percent were undetermined. All other causes of death (oiling, hepatobiliary, fungal, marine biotoxins, pulmonary) were at or below 1%. Twenty percent were positive for phocine distemper virus (PDV) by polymerase chain reaction (PCR). Domoic acid and saxitoxin were detected in 26% and 22% of animals at low levels.
Sea Otter Rehabilitation in the Puget Sound Greg Frankfurter, SR3 [email protected] With the completion of our new marine mammal rehabilitation hospital in Des Moines, WA, we will be able to provide response and rehabilitation options for otters in Washington state. The new hospital has surgical and treatment facilities and rehabilitation/conditioning spaces capable of holding all age classes of sea otters.
Sea Otter Research and Conservation Symposium 13 Bacterial Taxa Associated with Nasopulmonary Mites (Acari: Halarachnidae) Including Streptococcus phocae in Marine Mammals Risa Pesapane, Ohio State University [email protected] Nasopulmonary mite (NPM) acariasis is an underappreciated contributor to the morbidity and mortality of southern sea otters (Enhydra lutris nereis). Despite increasing reports of respiratory infection associated with mite infestation, the role of NPM in disseminating pathogens is unknown. The goals of this study were to (1) assess whether NPM harbor pathogens of veterinary concern and (2) determine the prevalence of S. phocae among NPM. At least 16 organisms with pathogenic potential were detected in NPM, including several associated with disease in sea otters and pinnipeds. One-third of NPM tested positive for S. phocae and most individuals harbored mites that were positive. NPM may be acting as mechanical vectors of bacteria.
Suspected Ovarian Granulosa Cell Tumor in an Adult Female Southern Sea Otter (Enhydra lutris nereis) Angelina Reed, California Department of Fish and Wildlife [email protected] A large, complex ovarian mass; an enlarged, thickened cervix; and a thickened endometrium were revealed during the necropsy of a frozen/thawed, moderate decomposition adult female southern sea otter. Gross necropsy, limited histopathology and immunohistochemistry findings suggest a functional ovarian granulosa cell tumor, which appears to be the first documented case in a southern sea otter.
Southern Sea Otter Thermal Function and Morphology Across Ontogeny Kate Riordan, California Polytechnic State University San Luis Obispo [email protected] Sea otters are unique among marine mammals in that they lack blubber and instead must rely on especially thick fur to keep warm. Seawater conducts heat 25 times faster than air at the same temperature, and a high surface-area-to-volume ratio puts sea otters at risk of being thermally stressed in the ocean. Despite a wealth of knowledge regarding the functional morphology of adult sea otter pelage, almost nothing is known about the characteristics of lanugo. To better understand the differences in sea otter fur across ontogeny, we investigated thermal function of pelts in air. Thermal conductivity, thermal resistance and pelt thickness were measured for six age classes: neonates, small pups, large pups, juveniles, subadults and adults.
Sea Otter Research and Conservation Symposium 14 Investigating the Presence and Trophic Transfer of Microplastics in Ex- and In-Situ Sea Otters using Scat and Diet Analysis Jennifer VanBrocklin, Oregon State University [email protected] I will be presenting on my master’s thesis research, in which we are investigating the ingestion of microplastics by sea otters (Enhydra lutris) using scat and diet sample analysis. Our study includes samples from individuals housed at the Seattle Aquarium and from wild sea otter populations in Alaska. We are also analyzing diet items fed to otters at the Seattle Aquarium to evaluate the role trophic transfer has in microplastic ingestion by otters. This analysis could provide opportunities to understand the current level of microplastic ingestion by aquarium-housed and wild sea otters using a non- invasive method, which may be beneficial for understanding sea otter population health.
SESSION FIVE: Genetics
Range-wide Genomic Sampling Illuminates Sea Otter Population Structure and Consequences of Fur Trade Exploitation Annabel Beichman, University of Washington [email protected] We designed sequence capture probes of sea otter coding and neutral genomic regions to examine the genetic population structure and demographic history of 135 otters across five sea otter populations ranging from the Kuril Islands to California. We see that sea otter population structure mirrors geography and that two sea otters sampled from Baja California, Mexico are likely migrants from the San Nicolas Island colony. We detected a signal of extreme and recent population decline in every surviving sea otter population, likely caused by the fur trade. We then used simulations to demonstrate that this decline may have lowered the fitness of recovering populations but that genetic factors likely do not pose an immediate extinction risk.
Sea Otter Research and Conservation Symposium 15 Investigating Relationships Between Genetics and Causes of Mortality in Southern Sea Otters (Enhydra lutris nereis) Nicole Hallie Carter, University of Wyoming [email protected] We investigated the relationship between genetics and causes of mortality in southern sea otters: cardiomyopathy, acanthocephalan (Profilicollis spp.) peritonitis, systemic protozoal infection (Toxoplasma gondii and Sarcocystis neurona), domoic acid intoxication, end lactation syndrome, and shark bite. Microsatellite genetic markers were used to assess host genetic diversity and pairwise relatedness in relation to these causes of death in 356 southern sea otters necropsied from 1998 to 2012. Significant relationships with genetics were observed for cardiomyopathy, acanthocephalan peritonitis and sarcocystosis and these associations varied by sex. Our findings can inform policy for conservation management as part of species recovery.
Physical Disturbance by Recovering Sea Otter Populations Increases Eelgrass Genetic Diversity Erin Foster, University of Victoria/Hakai Institute [email protected] Most of what we know about the role of sea otter predation in ecosystems is focused on changes to community structure. We examined eelgrass (Zostera marina) meadows across a gradient of sea otter occupancy in 2017 and found that the disturbance caused by sea otters digging for infaunal prey increased eelgrass genetic diversity by promoting conditions that favoured sexual reproduction over vegetative reproduction. Eelgrass allelic richness was 25% higher where sea otters were established (20–30 yrs) compared to where they had recently arrived (<10 yrs) or were absent (>100 yrs). Our findings reveal an underappreciated evolutionary process by which sea otters contribute to population genetic diversity and associated ecological resilience.
Investigation of Antimicrobial Resistance Gene Patterns Among Vibrio spp. in Sea Otters and Marine Mussels Peter Sebastian, University of California, Davis [email protected] Despite conservation and health issues associated with treating opportunistic Vibrio spp. in sea otters (Enhydra lutris), there is a gap in our ability to understand Vibrio spp. expression of antimicrobial resistance. Whole genome sequencing can augment understanding of antimicrobial resistance in Vibrio spp. From 2000 to 2015,
Sea Otter Research and Conservation Symposium 16 >340 Vibrio spp. isolates from southern and northern sea otters have been archived. We will sequence isolates to investigate how antimicrobial resistance genes differ between a) host species, b) study year, c) pathogen traits and d) landscape factors. Based on our ability to monitor antimicrobial resistance genes, we can assess trends and optimize detection of antimicrobial resistance for improved antibiotic therapy.
Effects of Limited Dispersal by Sea Otters (Enhydra lutris) on Population Dynamics: Relevance to the Threatened Southwest Alaska Distinct Population Segment Daniel Monson, U.S. Geological Survey [email protected] The Southwest Alaska sea otter stock has declined by ≥ 90% since early 1990s driven by killer whale (Orcinus orca) predation. The remaining sea otters are concentrated in a few colonies within sheltered habitats. This distribution protects them from predation; however, the patchy distribution combined with high fidelity likely acts to reduce demographic connectivity among colonies. We hypothesize that predation-driven selection for reduced movements and high fidelity to sheltered habitats may lead to reduced gene flow and further losses of genetic diversity due to small population sizes, which threatens long-term population viability. Management strategies that increase gene flow and maintain remnant genetic diversity should be considered.
Seattle Aquarium’s Sea Otter Research Program Shawn Larson, Seattle Aquarium [email protected] We will provide a short update on our sea otter research, including genetics, sea otter foraging and the new SOFA2 shiny R software to analyze foraging data to be released soon by the Seattle Aquarium, USGS and Nhydra.
Archaeological Mitogenomes Illuminate the Historical Ecology of Oregon Sea Otters (Enhydra lutris) Hannah Wellman, University of Oregon [email protected] To address the complex historical ecology of the sea otter (Enhydra lutris), we compared mitochondrial genomes of pre-extirpation Oregon sea otters to extant and historical populations. We extracted and sequenced complete ancient mitogenomes from archaeological Oregon sea otter tooth dentine and historical northern Pacific sea otter
Sea Otter Research and Conservation Symposium 17 dental calculus. The 10 archaeological Oregon haplotypes cluster with haplotypes from Alaska, Washington and British Columbia. These northern haplotypes exhibit a clear division from California haplotypes. This project demonstrates the feasibility of mitogenome capture/sequencing from non-human dental calculus and the diverse applications of ancient DNA analyses to historical ecology and conservation topics.
SESSION SIX: Ecology I
Historical Ecology of Sea Otters from Alaska, Oregon, and California Emma Elliott Smith, Smithsonian National Museum of Natural History [email protected] We explore the ecology of late Holocene sea otter populations using zooarchaeological and stable isotope analyses. We analyzed specimens from three localities: southeastern Alaska (n=38), northern Oregon (n=17) and central California (n=123). We measured bone collagen d13C and d15N values to estimate ancient population niche and found otters from California had the widest niche space and otters from Oregon the smallest. We also employed essential amino acid d13C analysis on a subset of samples (n=82), which provided information on habitats used by ancient sea otters. We found ancient Oregon otters were reliant on kelp forests, and sea otters from Alaska and California showed a mixed reliance on kelp forest and soft-sediment habitats.
Sea Otter Impacts to Seagrass Communities Across the Northeast Pacific Joseph Jackson, Sonoma State University [email protected] This project looks at the presence of top-down relationships in coastal systems across the northeastern Pacific. To assess the potential relationships caused by the presence of sea otters (Enhydra lutris), we sampled nine different coastal regions (with eelgrass beds) with varying sea otter presence spanning from southeast Alaska to central California. To accomplish this, we collected biomass data of the major trophic groups within eelgrass beds (Zostera marina). The goals of this project are to determine how relationships between these trophic levels change with or without the presence of sea otters and with latitude.
Sea Otter Research and Conservation Symposium 18 Changes in Kelp Canopy Cover Associated with Sea Otter Recovery in the Northeast Pacific Tom Bell, Woods Hole Oceanographic Institution [email protected] Sea otters can exert strong top-down pressure on kelp herbivores leading to increased kelp abundance. We used satellite observations of kelp canopy dynamics over three decades to relate patterns in kelp canopy to sea otter recolonization over regional scales in both Southeast Alaska and California. We found spatial patterns of kelp canopy changed through time and were related the timing and expansion of sea otters from relocation sites. Areas in California with persistent otter populations showed little expansion of kelp canopy occurrence.
Monitoring the Salt Marsh Habitat Use and Foraging Habits of the Recovering Southern Sea Otter (Enhydra lutris nereis) in a Recolonized Ecosystem Madeline Sanchez, Sonoma State University [email protected] This project investigated sea otter (Enhydra lutris nereis) salt marsh use utilizing camera trapping, machine learning and analysis of potential habitat use drivers. Camera traps were deployed at three salt marsh tidal creek sites in Elkhorn Slough, CA, from June 2020 to November 2020. The ability of machine learning to identify and quantify salt marsh use by sea otters and other predators was assessed. Sea otter scats found at each site were collected for prey content analysis to determine the proportion of the striped shore crab (found in salt marsh habitat) in sea otter diet. Striped shore crab availability and climatic extremes were also assessed as potential drivers of salt marsh use.
Sea Otter Diet Composition in Southern Southeast Alaska Nicole LaRoche, University of Alaska Fairbanks [email protected] The goal of this study was to quantify changes in seasonal diet composition and assess the energetic quality of sea otter prey in southern Southeast Alaska. Sea otter diets mainly consisted of clams, as quantified both from visual observations and stable isotope analysis. However, there was more variation in the diet estimates from stable isotope analysis. Stable isotope analysis revealed variation among individual diets of sea otters and individuality in diet within the POW region of sea otters. Sea otters seasonally increased consumption of some prey when the prey was highest in lipid and overall caloric content. Sea otters switched prey types when the prey was more energetically valuable.
Sea Otter Research and Conservation Symposium 19 Flexing Their Mussels: Sea Otter Diet Shifts in Response to Mussel Abundance James Bodkin, U.S. Geological Survey [email protected] Mussels are a ubiquitous but often minor component in the sea otter diet. In spraint examined from 2006 to 2019, mussels (Mytilus trossulus) are present in 39% of the spraint and are the predominant prey in most of those in the Gulf of Alaska. Sea otters preferentially consume mussels when they are gravid and energetically more valuable early in the year. Further, we found that as mussel density and abundance increased, the proportion of mussel in spraint also increased, from an average of 22% through 2013 to 59% after 2013. Sea otter diet across the Gulf of Alaska, viewed through spraint, commonly includes mussels, and in many cases, mussels are found to be the dominant prey, present in more than 90% of spraint.
Combining Contemporary Models and Aerial Photographic Surveys to Monitor Sea Otters in Glacier Bay National Park, Alaska Jamie Womble, National Park Service [email protected] In 2015 sea otters were identified as a “vital sign” in Glacier Bay National Park, and an effort was initiated, built upon existing data collected by the USGS from 1992 to 2012, to understand the ecological processes governing changes in sea otter distribution and abundance. To facilitate long-term monitoring of sea otters in Glacier Bay, we developed (1) a Bayesian spatiotemporal model and can accommodate multiple data sources and allows for inference over a large spatiotemporal domain and (2) aerial photographic methods using crewed aircraft to monitor sea otters. The aerial photographic methods provide high-resolution digital images that can be used to count sea otters, reduce observer bias, and provide a permanent record.
Dietary Patterns and Energy Intake Rates of Sea Otters Recolonizing Glacier Bay George Esslinger, U.S. Geological Survey [email protected] Sea otters began recolonizing the soft-sediment habitats of Glacier Bay in 1993 and occupied most regions of the Bay by 2018. Changes in Glacier Bay sea otter abundance and distribution are well documented, but population status relative to food resources is less well-known. We collected sea otter foraging observations in Glacier Bay over a
Sea Otter Research and Conservation Symposium 20 26-year period to track variation in energy intake rates and diet composition as indicators of population status. Our results indicate a transition from an urchin-dominated diet with an estimated intake of 27 kcal/min in 1993 to a blue mussel-dominated diet with an average intake of 6 kcal/min in 2019 and suggest sea otters in most areas of Glacier Bay are close to a food-limited carrying capacity.
Sea Otter Carrying Capacity in a Soft- and Mixed-Sediment Benthic Habitat Randall Davis, Texas A&M University at Galveston [email protected] Identifying factors that influence animal population density provide insight into why it varies spatiotemporally and when a population has reached carrying capacity (K), but how do we determine this? The goal of this study was to estimate K for Simpson Bay, AK, by measuring the abundance of bivalves, the primary prey for sea otters for over 40 years. On average, 110 adult sea otters (5.2 km−2) have occupied Simpson Bay annually since 2001, consuming an estimated 176,660 kg of bivalves. The total biomass of the major bivalves was 785,730 kg, so adult sea otters consumed ~22% of this biomass annually. Based on these observations and calculations, the estimated annual number of sea otters occupying Simpson Bay appears to be at or near K.
SESSION SEVEN: Ecology II
Sea Otter-Orca Interaction Geodatabase: A New Tool for Researchers and Managers Bethany Walter, Alaska Pacific University [email protected] Typically, sea otter populations are regulated by food supply. However, top-down predation has also limited dispersal or reduced numbers. Since 1993, otter numbers have declined in the Aleutian Archipelago. Estes et al. (1998) postulated that orca predation was the cause. Though few direct sightings had occurred at that time, there have been sporadic observations of orca-otter interactions over the years. For my student project at APU, I am creating a geospatial database of observed orca-otter interactions to document spatial extent and frequency of the interactions and allow researchers easy access to these data. During my presentation, I’ll solicit feedback on database design and ask about additional otter-orca interaction sightings.
Sea Otter Research and Conservation Symposium 21 Fast Kelp-Crab-Handling in Washington’s Sea Otter Population Carter Johnson, University of Washington [email protected] Sea otters in Washington appear to handle kelp crabs significantly faster than sea otters in California or British Columbia, a pattern that has been consistent through time and has yet to be formally investigated. We designed our study to test whether the faster kelp crab handling times are driven by a difference in sea otter behavior or by a difference in kelp crab morphology. Our results do not suggest that a difference in kelp crab morphology is driving the handling time anomaly and instead suggest that sea otters in Washington are experiencing population-wide diet specialization of kelp crabs and have developed behavioral differences that allow them to consume kelp crabs faster than in California or British Columbia.
Investigations of Southern Sea Otter Foraging Ecology at the Northern Range Extent Sophia Lyon, University of San Francisco [email protected] Sea otters are vital keystone predators within coastal ecosystems, but recovery of this threatened species has proceeded slowly in California. Yearly census data represents the majority of information regarding sea otters at the northern range extent, where a historical lack of range expansion has limited population growth. Although data pertaining to foraging behavior and rates of energy intake can serve as valuable metrics for assessing population status, little is known about these dynamics at the northern range edge. Thus, we collected fine-scale census and foraging data of sea otters at Año Nuevo State Park to determine seasonal abundance, diet composition, diet diversity and energy intake rates of sea otters at the northern range extent.
Tool Use Benefits in Southern Sea Otters Chris Law, University of Washington [email protected] We examined how variation in tool use frequency contributes to foraging success biomechanically and energetically and long-term health gains in 196 radio-tagged southern sea otters. We found that individuals, particularly females, with high tool use frequency consumed harder prey items. We also found a bi-modal relationship between tool use frequency and caloric income, revealing that frequent tool use and non-tool use both serve as a viable strategy to maintain sufficient caloric requirements. Interestingly, these foraging advantages do not translate to long-term health gains as tool use frequency neither prevented tooth injury nor increased body condition.
Sea Otter Research and Conservation Symposium 22 North Pacific Warming Shifts the Juvenile Range of a Marine Apex Predator Sal Jorgensen, University of California, Santa Cruz [email protected] During the 2014–2016 North Pacific marine heatwave, unprecedented sightings of juvenile white sharks (Carcharodon carcharias) emerged in central California. These records contradicted the species’ established life history, where juveniles remain in warmer waters in the Southern California Current. Here, we integrate community science, photogrammetry, biologging and mesoscale climate data to describe and explain this phenomenon. This spatial shift in juvenile white sharks is significant as it creates conflicts with commercial fisheries, protected species conservation and public safety concerns. We discuss the rise in sea otter mortality from white shark bites, which represents the greatest source of otter mortality during this period.
Proposed Research: Kelp Forest Complexity, Connectivity, and Resilience with and Without Keystone Predators Along the Olympic Coast Zachary Randell, Oregon State University/Seattle Aquarium [email protected] In conjunction with Tribal, federal, state, nonprofit and academic partners and collaborators, the Seattle Aquarium is in the process of initiating a new coastal research program along the Olympic Coast. Our overarching objective: evaluate the capacity for keystone sea otter predation to modify benthic resilience to pulse-perturbations such as anomalous warm-water, large-wav, and marine disease emergency events associated with climate change. Our approach includes: (1) ROV/AUV benthic surveys in conjunction with SCUBA diver observations, (2) measurements of kelp, sea urchin and reef fish recruitment, and (3) an increased frequency of sea otter surveys and foraging observations, particularly in proximity to the subtidal stations.
Sea Otter Research and Conservation Symposium 23 Save the date: Sea Otter Conservation Workshop XII In Seattle, Washington March 2022
Inspiring Conservation of Our Marine Environment