scholarly journals Harlequin Ducks (Histrionicus histrionicus) Scavenge Sea Urchin Fragments from Foraging Sea Otters (Enhydra lutris)

2016 ◽  
Vol 130 (2) ◽  
pp. 91 ◽  
Author(s):  
Erin Rechsteiner ◽  
Angeleen Olson
Keyword(s):  
Red Sea ◽  
Sea Urchins ◽  
Keystone Species ◽  
Sea Otter ◽  
Enhydra Lutris ◽  
Sea Otters ◽  
Important Prey ◽  
Histrionicus Histrionicus ◽  
Harlequin Ducks

Foraging animals may risk association with potential predators to obtain otherwise inaccessible prey. We observed this strategy in wintering Harlequin Ducks (Histrionicus histrionicus) scavenging fragments of Red Sea Urchins (Mesocentrotus franciscanus) from foraging Sea Otters (Enhydra lutris) that were re-occupying an area from which they had been ecologically absent since about 1850. Harlequin Ducks, like other sea ducks, have not previously been reported scavenging from other birds or mammals. In British columbia, Red Sea Urchins have reached large sizes and densities since the removal of Sea Otter predators by the marine fur trade in the 18th and 19th centuries. Observations of Sea Otters and Harlequin Ducks were made in 4 areas, spanning a time gradient of Sea Otter occupation from 1 to 5 years. During 3 months of observations (December 2013 – February 2014), Harlequin Ducks were associated with foraging Sea Otters only at sites that were recently occupied by Sea Otters (≤ 2 months), where the proportion of urchins in Sea Otter diets was highest and where the ducks acquired urchin fragments from foraging Sea Otters. We suggest that Sea Otters re-occupying their historic range and consuming predominantly large Red Sea Urchins provide a temporarily available prey subsidy for Harlequin Ducks. Our observations document a novel effect of Sea Otters providing important prey supplementation to a marine bird when foraging in urchin-rich habitats, contributing to the overall role of Sea Otters as a keystone species.

scholarly journals The historical and contemporary status of the sea otter Enhydra lutris population on Urup Island, southern Kuril Islands

Oryx ◽  
2021 ◽  
pp. 1-6
Author(s):  
Igor Popov ◽  
Alexey Scopin
Keyword(s):  
Total Population ◽  
Kuril Islands ◽  
Sea Otter ◽  
Enhydra Lutris ◽  
Sea Otters ◽  
The Past ◽  
Remote Island ◽  
Contemporary Status ◽  
Wildlife Refuges ◽  
Effective Conservation

Abstract We describe the population of the Еndangered sea otter Enhydra lutris on Urup Island, one of the main wildlife refuges in the southern Kuril Islands of Russia. We reviewed historical and local reports of the sea otter, identified its habitat around the island, and surveyed the coastal waters of the island in 2019. Sea otters were numerous on Urup Island in the past but were hunted excessively and almost exterminated by the 1950s. Since then, sea otter populations have increased, and as the island is almost uninhabited we expected otters to be numerous. This was not the case, and we estimated the total population to be 363 ± SE 126 individuals. Our observation of two skinned carcasses on the shore suggests the low numbers are a result of poaching for the illegal fur trade. The case of Urup Island demonstrates that sea otters require active conservation, as even on a remote island they remain threatened. Establishment of protected areas would be an effective conservation measure for this species, although the suppression of demand for sea otter fur is of the greatest importance.

scholarly journals Predators, Disease, and Environmental Change in the Nearshore Ecosystem: Mortality in Southern Sea Otters (Enhydra lutris nereis) From 1998–2012

2020 ◽  
Vol 7 ◽  
Author(s):  
Melissa A. Miller ◽  
Megan E. Moriarty ◽  
Laird Henkel ◽  
Martin Tim Tinker ◽  
Tristan L. Burgess ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Population Level ◽  
Large Sample Size ◽  
Sea Otter ◽  
Enhydra Lutris ◽  
Sea Otters ◽  
Sarcocystis Neurona ◽  
Enhydra Lutris Nereis ◽  
Protozoal Infection ◽  
Demographic Attributes

We compiled findings from 15 years (1998–2012) of southern sea otter (Enhydra lutris nereis) necropsies, incorporating data from 560 animals. Sensitive diagnostic tests were used to detect biotoxins, bacteria, parasites and fungi. Methods to classify primary and contributing causes of death (COD) and sequelae utilized an updated understanding of health risks affecting this population. Several interesting patterns emerged, including identification of coastal regions of high mortality risk for sea otter mortality due to shark bite, cardiomyopathy, toxoplasmosis, sarcocystosis, acanthocephalan peritonitis and coccidioidomycosis. We identified demographic attributes that enhanced the risk of disease in relation to age, sex, and reproductive stage. Death due to white shark (Carcharodon carcharias) bite increased dramatically during the study period and was the most common primary COD. However, when primary and contributing COD were combined, the most prevalent COD was infectious disease (affecting 63% of otters), especially fatal infections by acanthocephalans (Profilicollis spp.) and protozoa (e.g., Sarcocystis neurona and Toxoplasma gondii). Fatal bacterial infections were also extremely common as a primary process or a sequela, affecting 68% of examined otters. Substantial advances were made in identifying sea otters that died following exposure to the pervasive marine neurotoxin domoic acid (DA), and DA intoxication was conservatively estimated as a primary or contributing COD for 20% of otters. Cardiomyopathy was also highly prevalent as a primary or contributing COD (41%) and exhibited significant associations with DA intoxication and protozoal infection. For adult and aged adult females in late pup care through post-weaning at the time of death, 83% had end lactation syndrome (ELS) as a primary or contributing COD. This comprehensive longitudinal dataset is unique in its depth and scope. The large sample size and extensive time period provided an opportunity to investigate mortality patterns in a changing environment and identify spatial and temporal disease “hot spots” and emerging threats. Our findings will help improve estimates of population-level impacts of specific threats and optimize conservation and environmental mitigation efforts for this threatened species.

scholarly journals Archaeological mitogenomes illuminate the historical ecology of sea otters ( Enhydra lutris ) and the viability of reintroduction

2020 ◽  
Vol 287 (1940) ◽  
pp. 20202343
Author(s):  
Hannah P. Wellman ◽  
Rita M. Austin ◽  
Nihan D. Dagtas ◽  
Madonna L. Moss ◽  
Torben C. Rick ◽  
...  
Keyword(s):  
British Columbia ◽  
Ancient Dna ◽  
Historical Ecology ◽  
Mitochondrial Genomes ◽  
Sea Otter ◽  
Enhydra Lutris ◽  
Dental Calculus ◽  
Sea Otters ◽  
Dna Analyses ◽  
Modern Context

Genetic analyses are an important contribution to wildlife reintroductions, particularly in the modern context of extirpations and ecological destruction. To address the complex historical ecology of the sea otter ( Enhydra lutris ) and its failed 1970s reintroduction to coastal Oregon, we compared mitochondrial genomes of pre-extirpation Oregon sea otters to extant and historical populations across the range. We sequenced, to our knowledge, the first complete ancient mitogenomes from archaeological Oregon sea otter dentine and historical sea otter dental calculus. Archaeological Oregon sea otters ( n = 20) represent 10 haplotypes, which cluster with haplotypes from Alaska, Washington and British Columbia, and exhibit a clear division from California haplotypes. Our results suggest that extant northern populations are appropriate for future reintroduction efforts. This project demonstrates the feasibility of mitogenome capture and sequencing from non-human dental calculus and the diverse applications of ancient DNA analyses to pressing ecological and conservation topics and the management of at-risk/extirpated species.

Primary intracranial fibrosarcoma in a southern sea otter Enhydra lutris nereis

2020 ◽  
Vol 138 ◽  
pp. 207-213
Author(s):  
AR Armwood ◽  
CE Anderson ◽  
T Clauss ◽  
AC Camus
Keyword(s):  
Smooth Muscle Actin ◽  
Brain Lesion ◽  
Acute Onset ◽  
Sea Otter ◽  
Enhydra Lutris ◽  
Mammal Species ◽  
Sea Otters ◽  
Enhydra Lutris Nereis ◽  
High Mitotic Count ◽  
Southern Sea Otter

Southern sea otters Enhydra lutris nereis, a threatened marine mammal species, face numerous environmental and infectious disease challenges in their native habitat of coastal California, USA. However, there are few published cases describing neoplasia in sea otters despite their relatively long life span when cared for in aquarium settings. An 18 yr old neutered male southern sea otter, born and raised in human care, presented with an acute onset of seizures and dull mentation. Magnetic resonance imaging of the head revealed a large, central brain lesion. After no improvement with treatment, euthanasia was elected due to a poor prognosis. Grossly, a poorly demarcated, granular, tan mass expanded the cranial meninges in the longitudinal fissure at the level of the cruciate sulcus and extended into the underlying gray matter and superficial white matter. Histologically, the mass was composed of spindle cells, forming haphazardly arranged interlacing bundles and herringbone patterns, with a high mitotic count, moderate cellular pleomorphism, and prominent vascularization. Neoplastic cells demonstrated positive immunoreactivity for vimentin and negative immunoreactivity for smooth muscle actin, factor VIII-related antigen, S100, melan-A, E-cadherin, desmin, glial fibrillary acidic protein, and cytokeratin AE1/AE3. Based on gross, histologic, and immunohistochemical findings, the mass was most consistent with a primary intracranial fibrosarcoma (PIF). PIFs are a rare neoplasm in both humans and other animals with few reports in the veterinary literature. This is the first recorded case of a PIF in a sea otter.

Did Tlingit Ancestors Eat Sea Otters? Addressing Intellectual Property and Cultural Heritage through Zooarchaeology

2020 ◽  
Vol 85 (2) ◽  
pp. 202-221
Author(s):  
Madonna L. Moss
Keyword(s):  
Alaska Native ◽  
Marine Ecosystem ◽  
Keystone Species ◽  
Sea Otter ◽  
Sea Otters ◽  
Southeast Alaska ◽  
The North ◽  
Commercially Important ◽  
The 1960S ◽  
The North Pacific

The maritime fur trade caused the extirpation of sea otters from southeast Alaska. In the 1960s, sea otters were reintroduced, and their numbers have increased. Now, sea otters are competing with people for what have become commercially important invertebrates. After having been absent for more than a century, the reentry of this keystone species has unsettled people. Although some communities perceive sea otters as a threat to their livelihoods, others view their return as restoration of the marine ecosystem. The federal Marine Mammal Protection Act authorizes any Alaska Native to harvest sea otters for subsistence provided that the harvest is not wasteful. Some people are seeking to define “traditional” Tlingit use of sea otters as not only using their pelts but consuming them as food, but some Tlingit maintain they never ate sea otters. This project analyzes the largest precontact archaeological assemblage of sea otter bones in southeast Alaska, with the benefit of insights gained from observing a Tlingit hunter skin a sea otter to infer that Tlingit ancestors hunted sea otters primarily for pelts. The extent to which other Indigenous peoples of the North Pacific consumed sea otters as food deserves investigation, especially as sea otters recolonize their historic range.

scholarly journals Sea Otter, Enhydra lutris, Sightings off Haida Gwaii / Queen Charlotte Islands, British Columbia, 1972-2002

2004 ◽  
Vol 118 (2) ◽  
pp. 270
Author(s):  
Kimberly Raum-Suryan ◽  
Kenneth Pitcher ◽  
Richard Lamy
Keyword(s):  
British Columbia ◽  
Steller Sea Lion ◽  
Sea Otter ◽  
Eumetopias Jubatus ◽  
Enhydra Lutris ◽  
Haida Gwaii ◽  
Sea Lion ◽  
Sea Otters ◽  
The Past ◽  
Queen Charlotte Islands

On 27 June 2001 we observed and photographed a Sea Otter (Enhydra lutris) adjacent to a Steller Sea Lion (Eumetopias jubatus) haulout near Sgang Gwaay (Anthony Island), Haida Gwaii / Queen Charlotte Islands. This is one of only eight documented sightings of Sea Otters in these waters during the past 30 years. These sightings may represent the beginning of the expansion of Sea Otters to their former range off Haida Gwaii.

scholarly journals Use of the ACTH challenge test to identify the predominant glucocorticoid in the southern sea otter (Enhydra lutris nereis)

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
M J Murray ◽  
M A Young ◽  
R M Santymire
Keyword(s):  
Challenge Test ◽  
Controlled Study ◽  
Sea Otter ◽  
Saline Injection ◽  
Enhydra Lutris ◽  
Sea Otters ◽  
Late 20Th Century ◽  
Acth Challenge ◽  
Human Care ◽  
The Individual

Abstract After nearly being hunted to extinction during the fur trade of the late 20th Century, sea otter (Enhydra lutris) populations have recovered to varying degrees of their historical range. While overall population numbers and range have increased, there are regions in which expansion has occurred at a slower rate and/or animal numbers have decreased, which may be a result of chronic stress from a variety of sources. Some have employed glucocorticoid analysis in their attempts to validate these explanations. Our goal was to conduct a controlled study using sea otters managed under human care to validate the use of serum glucocorticoid analysis to monitor stress physiology in the sea otter. We used a standard ACTH challenge test to compare cortisol and corticosterone responses, thereby identifying the primary glucocorticoid in the sea otter. Fourteen sea otters of both sexes (five males, nine females), including juveniles, sub-adults and adults, participated in the study. The results of the testing supported cortisol as the primary glucocorticoid in the sea otter. Sex and age did not affect how the individual responded to the ACTH or saline injection. Interestingly, the saline injection not only confirmed the effects of the ACTH on glucocorticoid release from the adrenal glands but also provided information on how long it takes the sea otter’s glucocorticoid levels to return to baseline after capture and sedation. The insight gained from this study will aid in future efforts to better understand the role of stress in free-ranging sea otter populations. Recognition of the primary glucocorticoid will facilitate evaluation of more stable biological material, such as fur or whiskers, which tend to be less affected by the diurnal cycling of glucocorticoids.

Impacts of sea otter (Enhydra lutris) predation on commercially important sea cucumbers (Parastichopus californicus) in southeast Alaska

2013 ◽  
Vol 70 (10) ◽  
pp. 1498-1507 ◽  
Author(s):  
Sean D. Larson ◽  
Zachary N. Hoyt ◽  
Ginny L. Eckert ◽  
Verena A. Gill
Keyword(s):  
Sea Cucumber ◽  
Inverse Relationship ◽  
Population Survey ◽  
Fishery Management ◽  
Sea Otter ◽  
Enhydra Lutris ◽  
Sea Otters ◽  
Sea Cucumbers ◽  
Southeast Alaska ◽  
Commercially Important

Sea cucumbers (Parastichopus californicus), which are an important commercial, subsistence, and ecological resource, are negatively affected by an expanding sea otter (Enhydra lutris) population in southeast Alaska. A few hundred sea otters were reintroduced into southeast Alaska in the late 1960s after their extirpation during the 18th and 19th century fur trade. In the ensuing decades after recolonization, the sea otter population grew exponentially in number and distribution, and sea cucumbers declined in density in areas with otters, suggesting an inverse relationship between sea otter numbers and sea cucumber density. We evaluated the interaction and effects of sea otters on sea cucumbers using sea otter foraging observations, sea otter population survey data, and sea cucumber density data. Our results indicate that sea cucumber density declined with and without sea otter presence and that the extent of the decline depends on the duration and magnitude of sea otter presence, with 100% decline in areas occupied by sea otters since 1994. Sea otter predation should be included in sea cucumber fishery management as a step toward ecosystem-based management.

scholarly journals Type X strains of Toxoplasma gondii are virulent for southern sea otters ( Enhydra lutris nereis) and present in felids from nearby watersheds

2019 ◽  
Vol 286 (1909) ◽  
pp. 20191334 ◽  
Author(s):  
Karen Shapiro ◽  
Elizabeth VanWormer ◽  
Andrea Packham ◽  
Erin Dodd ◽  
Patricia A. Conrad ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Coastal Waters ◽  
Sea Otter ◽  
Type Ii ◽  
Enhydra Lutris ◽  
Chronic Infections ◽  
Sea Otters ◽  
Central California ◽  
Enhydra Lutris Nereis ◽  
Marine Wildlife

Why some Toxoplasma gondii -infected southern sea otters ( Enhydra lutris nereis ) develop fatal toxoplasmosis while others have incidental or mild chronic infections has long puzzled the scientific community. We assessed robust datasets on T. gondii molecular characterization in relation to detailed necropsy and histopathology results to evaluate whether parasite genotype influences pathological outcomes in sea otters that stranded along the central California coast. Genotypes isolated from sea otters were also compared with T. gondii strains circulating in felids from nearby coastal regions to assess land-to-sea parasite transmission. The predominant T. gondii genotypes isolated from 135 necropsied sea otters were atypical Type X and Type X variants (79%), with the remainder (21%) belonging to Type II or Type II/X recombinants. All sea otters that died due to T. gondii as a primary cause of death were infected with Type X or X-variant T. gondii strains. The same atypical T. gondii strains were detected in sea otters with fatal toxoplasmosis and terrestrial felids from watersheds bordering the sea otter range. Our results confirm a land–sea connection for virulent T. gondii genotypes and highlight how faecal contamination can deliver lethal pathogens to coastal waters, leading to detrimental impacts on marine wildlife.

Oxygen consumption, thermoregulation, and the effect of fur oiling and washing on the sea otter, Enhydra lutris

1982 ◽  
Vol 60 (11) ◽  
pp. 2761-2767 ◽  
Author(s):  
Daniel P. Costa ◽  
Gerald L. Kooyman
Keyword(s):  
Oxygen Consumption ◽  
Water Repellent ◽  
Sea Otter ◽  
Relative Importance ◽  
Enhydra Lutris ◽  
Sea Otters ◽  
Open Flow ◽  
Before And After ◽  
Core Body ◽  
Made In

The relative importance of a water-repellent fur was assessed by changes in oxygen consumption [Formula: see text] and in body and subcutaneous temperatures before and after oiling and washing in 15 °C water. In addition, changes in posture and [Formula: see text] in five sea otters were measured while immersed in water from 5 to 30 °C. Measurements were made in an enclosed water bath with Vo2 determined by open-flow respirometry. Core body and subcutaneous temperatures were telemetered. Resting [Formula: see text] was 11.7 mL O2∙kg−1∙min−1 and did not significantly increase with decreasing temperature. Average and active [Formula: see text] increased with decreasing temperature. Average [Formula: see text] (16.0 mL O2∙kg−1∙min−1) increased 41% (22.0 mL O2∙kg−1∙min−1) after oiling 20% of the total fur surface and more than doubled (32.6 mL O2∙kg−1∙min−1) after washing. Oiling and washing reduced the fur's insulating quality. The result was an energetic liability, since the average maintenance [Formula: see text] doubled in 15 °C water; this temperature is above typical water temperatures for this species, which range from 0 °C (Alaska) to 12 °C (California). Average [Formula: see text] returned to control levels after a minimum of 8 days.

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