Coccidioidomycosis in southern sea otters

USGS Publications Warehouse

Thomas, Nancy J.; Pappagianis, Demosthenes; Creekmore, Lynn H.; Duncan, Ruth M.

1994-01-01

Disseminated coccidioidomycosis was diagnosed postmortem in six southern sea otters (Enhydra lutris nereis) found dying or dead along the Pacific Coast of California at San Luis Obispo County.  These otters were found during winter or summer 1992, 1993, and 1994.  Coccidioides immitis was identified by its morphology in tissue impression smears and by histopathology, and was confirmed by culture.  Positive serologic results were obtained from four of five sea otters tested.  The lungs, pleura, tracheobronchial lymph nodes, liver, and spleen were involved in each case.  There was meningeal involvement in half of the affected animals.  Coccidioidomycosis has been reported in a wild sea otter only once previously, in 1976, and that otter was also found on the coast of San Luis Obispo County.

The use of quantitative models in sea otter conservation

USGS Publications Warehouse

Tinker, M. Tim

2015-01-01

Sea otters are good indicators of ocean health. In addition, they are a keystone species, offering a stabilizing effect on ecosystem, controlling sea urchin populations that would otherwise inflict damage to kelp forest ecosystems. The kelp forest ecosystem is crucial for marine organisms and contains coastal erosion. With the concerns about the imperiled status of sea otter populations in California, Aleutian Archipelago and coastal areas of Russia and Japan, the last several years have shown growth of interest culturally and politically in the status and preservation of sea otter populations. Sea Otter Conservation brings together the vast knowledge of well-respected leaders in the field, offering insight into the more than 100 years of conservation and research that have resulted in recovery from near extinction. This publication assesses the issues influencing prospects for continued conservation and recovery of the sea otter populations and provides insight into how to handle future global changes.

Epidemiology and potential land-sea transfer of enteric bacteria from terrestrial to marine species in the Monterey Bay Region of California.

PubMed

Oates, Stori C; Miller, Melissa A; Byrne, Barbara A; Chouicha, Nadira; Hardin, Dane; Jessup, David; Dominik, Clare; Roug, Annette; Schriewer, Alexander; Jang, Spencer S; Miller, Woutrina A

2012-07-01

Marine mammals are at risk for infection by fecal-associated zoonotic pathogens when they swim and feed in polluted nearshore marine waters. Because of their tendency to consume 25-30% of their body weight per day in coastal filter-feeding invertebrates, southern sea otters (Enhydra lutris nereis) can act as sentinels of marine ecosystem health in California. Feces from domestic and wildlife species were tested to determine prevalence, potential virulence, and diversity of selected opportunistic enteric bacterial pathogens in the Monterey Bay region. We hypothesized that if sea otters are sentinels of coastal health, and fecal pollution flows from land to sea, then sea otters and terrestrial animals might share the same enteric bacterial species and strains. Twenty-eight percent of fecal samples tested during 2007-2010 were positive for one or more potential pathogens. Campylobacter spp. were isolated most frequently, with an overall prevalence of 11%, followed by Vibrio cholerae (9%), Salmonella spp. (6%), V. parahaemolyticus (5%), and V. alginolyticus (3%). Sea otters were found positive for all target bacteria, exhibiting similar prevalences for Campylobacter and Salmonella spp. but greater prevalences for Vibrio spp. when compared to terrestrial animals. Fifteen Salmonella serotypes were detected, 11 of which were isolated from opossums. This is the first report of sea otter infection by S. enterica Heidelberg, a serotype also associated with human clinical disease. Similar strains of S. enterica Typhimurium were identified in otters, opossums, and gulls, suggesting the possibility of land-sea transfer of enteric bacterial pathogens from terrestrial sources to sea otters.

Ecosystem features determine seagrass community response to sea otter foraging

USGS Publications Warehouse

Hessing-Lewis, Margot; Rechsteiner, Erin U.; Hughes, Brent B.; Tinker, M. Tim; Monteith, Zachary L.; Olson, Angeleen M.; Henderson, Matthew Morgan; Watson, Jane C.

2017-01-01

Comparing sea otter recovery in California (CA) and British Columbia (BC) reveals key ecosystem properties that shape top-down effects in seagrass communities. We review potential ecosystem drivers of sea otter foraging in CA and BC seagrass beds, including the role of coastline complexity and environmental stress on sea otter effects. In BC, we find greater species richness across seagrass trophic assemblages. Furthermore, Cancer spp. crabs, an important link in the seagrass trophic cascade observed in CA, are less common. Additionally, the more recent reintroduction of sea otters, more complex coastline, and reduced environmental stress in BC seagrass habitats supports the hypotheses that sea otter foraging pressure is currently reduced there. In order to manage the ecosystem features that lead to regional differences in top predator effects in seagrass communities, we review our findings, their spatial and temporal constraints, and present a social-ecological framework for future research.

Evaluating potential conservation conflicts between two listed species: Sea otters and black abalone

USGS Publications Warehouse

Raimondi, Peter T.; Jurgens, Laura J.; Tinker, M. Tim

2015-01-01

Population consequences of endangered species interacting as predators and prey have been considered theoretically and legally, but rarely investigated in the field. We examined relationships between spatially variable populations of a predator, the California sea otter, Enhydra lutris nereis, and a prey species, the black abalone, Haliotis cracherodii. Both species are federally listed under the Endangered Species Act and co-occur along the coast of California. We compared the local abundance and habitat distribution of black abalone at 12 sites with varying densities of sea otters. All of the populations of abalone we examined were in the geographic area currently unaffected by withering disease, which has decimated populations south of the study area. Surprisingly, our findings indicate that sea otter density is positively associated with increased black abalone density. The presence of sea otters also correlated with a shift in black abalone to habitat conferring greater refuge, which could decrease illegal human harvest. These results highlight the need for a multi-species approach to conservation management of the two species, and demonstrate the importance of using field-collected data rather than simple trophic assumptions to understand relationships between jointly vulnerable predator and prey populations.

Evaluating potential conservation conflicts between two listed species: sea otters and black abalone.

PubMed

Raimondi, Peter; Jurgens, Laura J; Tinker, M Tim

2015-11-01

Population consequences of endangered species interacting as predators and prey have been considered theoretically and legally, but rarely investigated in the field. We examined relationships between spatially variable populations of a predator, the California sea otter, Enhydra lutris nereis, and a prey species, the black abalone, Haliotis cracherodii. Both species are federally listed under the Endangered Species Act and co-occur along the coast of California. We compared the local abundance and habitat distribution of black abalone at 12 sites with varying densities of sea otters. All of the populations of abalone we examined were in the geographic area currently unaffected by withering disease, which has decimated populations south of the study area. Surprisingly, our findings indicate that sea otter density is positively associated with increased black abalone density. The presence of sea otters also correlated with a shift in black abalone to habitat conferring greater refuge, which could decrease illegal human harvest. These results highlight the need for a multi-species approach to conservation management of the two species, and demonstrate the importance of using field-collected data rather than simple trophic assumptions to understand relationships between jointly vulnerable predator and prey populations.

Effects of wildfire on sea otter (Enhydra lutris) gene transcript profiles

USGS Publications Warehouse

Bowen, Lizabeth; Miles, A. Keith; Kolden, Crystal A.; Saarinen, Justin A.; Bodkin, James L.; Murray, Michael J.; Tinker, M. Tim

2015-01-01

Wildfires have been shown to impact terrestrial species over a range of temporal scales. Little is known, however, about the more subtle toxicological effects of wildfires, particularly in downstream marine or downwind locations from the wildfire perimeter. These down-current effects may be just as substantial as those effects within the perimeter. We used gene transcription technology, a sensitive indicator of immunological perturbation, to study the effects of the 2008 Basin Complex Fire on the California coast on a sentinel marine species, the sea otter (Enhydra lutris). We captured sea otters in 2008 (3 mo after the Basin Complex Fire was controlled) and 2009 (15 mo after the Basin Complex Fire was controlled) in the adjacent nearshore environment near Big Sur, California. Gene responses were distinctly different between Big Sur temporal groups, signifying detoxification of PAHs, possible associated response to potential malignant transformation, and suppression of immune function as the primary responses of sea otters to fire in 2008 compared to those captured in 2009. In general, gene transcription patterns in the 2008 sea otters were indicative of molecular reactions to organic exposure, malignant transformation, and decreased ability to respond to pathogens that seemed to consistent with short-term hydrocarbon exposure.

76 FR 53381 - Endangered and Threatened Wildlife and Plants; Termination of the Southern Sea Otter...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-26

...We, the U.S. Fish and Wildlife Service (Service), propose to remove the regulations that govern the southern sea otter (Enhydra lutris nereis) translocation program, including the establishment of an experimental population of southern sea otters, and all associated management actions. We are also proposing to amend the Authority citation for 50 CFR part 17 by removing the reference to Public Law 99- 625, the statute that authorized the Secretary to promulgate regulations establishing the southern sea otter translocation program. Removal of the regulations will terminate the program. We are proposing this action because we believe that the southern sea otter translocation program has failed to fulfill its purpose, as outlined in the southern sea otter translocation plan, and that our recovery and management goals for the species cannot be met by continuing the program. Our conclusion is based, in part, on an evaluation of the program against specific failure criteria established at the program's inception. This proposed action would terminate the designation of the experimental population of southern sea otters, abolish the southern sea otter translocation and management zones, and eliminate the current requirement to remove southern sea otters from San Nicolas Island and the management zone. This proposed rule would also eliminate future actions, required under the current regulations, to capture and relocate southern sea otters for the purpose of establishing an experimental population, and to remove southern sea otters in perpetuity from an ``otter-free'' management zone. As a result, it would allow southern sea otters to expand their range naturally into southern California waters. We have prepared a revised draft supplemental environmental impact statement (SEIS) and an initial regulatory flexibility analysis (IRFA) to accompany this proposed rule.

Release strategies for rehabilitated sea otters

USGS Publications Warehouse

DeGange, Anthony R.; Ballachey, Brenda E.; Bayha, Keith; Williams, Terrie M.; Davis, Randall W.

1995-01-01

According to the U.S. Fish and Wildlife Services’ (USFWS) Response Plan for sea otters (USFWS, in preparation), in the event of an oil spill, the decision to release sea otters from rehabilitation centers following treatment will be linked to the decision on whether to capture sea otters for treatment. Assuming a scenario similar to the Exxon Valdez oil spill (EVOS), once the decision to capture sea otters is made, the ultimate goal is to return as many sea otters to the wild as possible, even though the rescue may not be expected to produce results significant at the population level. The decision by the USFWS to proceed with capture, rehabilitation, and release will be made on a case-by-case basis (USFWS, in preparation). Many factors will influence the decision. Perhaps the most important factors in deciding when and where to release sea otters are the location and availability of suitable release sites and verification that the otters are free of diseases that might be transmitted to the wild population.Alternative release strategies for sea otters will be contained in the sea otter response portion of the USFWS’s oil spill contingency plans for Alaska and California that are being developed as required by the Oil Pollution Act of 1990. Public review of these plans before they are implemented will help to reduce public concern about the survival of rehabilitated otters, their biological effect on the release area, and the potential introduction or spread of disease into the wild sea otter population.The objective of this chapter is to review alternative strategies for the disposition of rehabilitated sea otters. Our assumption is that returning as many animals to the wild as possible, whether it be for humanitarian or biological reasons, is the ultimate goal of this effort (Figure 10.1).

ISOLATION AND CHARACTERIZATION OF A NOVEL MARINE BRUCELLA FROM A SOUTHERN SEA OTTER (ENHYDRA LUTRIS NEREIS), CALIFORNIA, USA.

PubMed

Miller, Melissa A; Burgess, Tristan L; Dodd, Erin M; Rhyan, Jack C; Jang, Spencer S; Byrne, Barbara A; Gulland, Frances M D; Murray, Michael J; Toy-Choutka, Sharon; Conrad, Patricia A; Field, Cara L; Sidor, Inga F; Smith, Woutrina A

2017-04-01

We characterize Brucella infection in a wild southern sea otter ( Enhydra lutris nereis) with osteolytic lesions similar to those reported in other marine mammals and humans. This otter stranded twice along the central California coast, US over a 1-yr period and was handled extensively at two wildlife rehabilitation facilities, undergoing multiple surgeries and months of postsurgical care. Ultimately the otter was euthanized due to severe, progressive neurologic disease. Necropsy and postmortem radiographs revealed chronic, severe osteoarthritis spanning the proximal interphalangeal joint of the left hind fifth digit. Numerous coccobacilli within the joint were strongly positive on Brucella immunohistochemical labelling, and Brucella sp. was isolated in pure culture from this lesion. Sparse Brucella-immunopositive bacteria were also observed in the cytoplasm of a pulmonary vascular monocyte, and multifocal granulomas were observed in the spinal cord and liver on histopathology. Findings from biochemical characterization, 16S ribosomal DNA, and bp26 gene sequencing of the bacterial isolate were identical to those from marine-origin brucellae isolated from cetaceans and phocids. Although omp2a gene sequencing revealed 100% homology with marine Brucella spp. infecting pinnipeds, whales, and humans, omp2b gene sequences were identical only to pinniped-origin isolates. Multilocus sequence typing classified the sea otter isolate as ST26, a sequence type previously associated only with cetaceans. Our data suggest that the sea otter Brucella strain represents a novel marine lineage that is distinct from both Brucella pinnipedialis and Brucella ceti. Prior reports document the zoonotic potential of the marine brucellae. Isolation of Brucella sp. from a stranded sea otter highlights the importance of wearing personal protective equipment when handling sea otters and other marine mammals as part of wildlife conservation and rehabilitation efforts.

Vitamin A deficiency and hepatic retinol levels in sea otters, Enhydra lutris.

PubMed

St Leger, Judy A; Righton, Alison L; Nilson, Erika M; Fascetti, Andrea J; Miller, Melissa A; Tuomi, Pamela A; Goertz, Caroline E C; Puschner, Birgit

2011-03-01

Vitamin A deficiency has rarely been reported in captive or free-ranging wildlife species. Necropsy findings in two captively housed southern sea otters (Enhydra lutris nereis) included irregular thickening of the calvaria characterized by diffuse hyperostoses on the internal surface. One animal also had moderate squamous metaplasia of the seromucinous glands of the nose. There was no measurable retinol in the liver of either sea otter. For comparison, hepatic retinol concentration was determined for 23 deceased free-ranging southern and northern (Enhydra lutris kenyoni) sea otters from California and Alaska. Free-ranging otters were found to have similar hepatic retinol concentrations (316 +/- 245 mg/kg wet weight) regardless of their location and subspecies. All of these values were significantly higher than the levels in the affected animals. Consumption of a diet with very low vitamin A concentrations and noncompliance in daily supplementation are hypothesized as the causes of vitamin A deficiency in these two sea otters.

Translocated sea otter populations off the coasts of Oregon and Washington

USGS Publications Warehouse

Jameson, Ronald J.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

1998-01-01

The historical distribution of sea otters extended from the northern islands of Japan north and east across the Aleutian chain to the mainland of North America then south along the west coast to central Baja California, Mexico (Riedman and Estes 1990). By the beginning of the twentieth century, after 150 years of being intensively hunted for their valuable fur, sea otters had been extirpated from most of their range (Kenyon 1969). In 1911 sea otters were protected by the passage of the International Fur Seal Treaty. Unfortunately, only 13 remnant populations survived the fur-hunting period, and two of those, British Columbia and Mexico, would also ultimately disappear, leaving only a small group of sea otters south of Alaska, along the rugged Big Sur coast of California (Kenyon 1969).The earliest attempts to reestablish sea otters to unoccupied habitat were begun in the early 1950’s by R. D. (Sea Otter) Jones, then manager of the Aleutian National Wildlife Refuge (Kenyon 1969). These early efforts were experimental, and all failed to establish populations. However, the knowledge gained from Jones’s efforts and the seminal work of Kenyon (1969) and others during the 1950’s and early 1960’s ultimately led to the successful efforts to come.During the mid-1960’s the Alaska Department of Fish and Game began translocating sea otters to sites where the species had occurred before the fur-trade period. The first translocations were restricted to Alaska, but beginning in 1969 and continuing through 1972, the effort expanded beyond Alaska. During this period, 241 sea otters were translocated to sites in British Columbia, Washington, and Oregon (Jameson et al. 1982). The work was done cooperatively between state and provincial conservation agencies, with much of the financial support for the Oregon and Washington efforts coming from the Atomic Energy Commission (now ERDA). Followup studies of the Oregon population began in 1971 and continued through 1975. After 1975, surveys in Oregon occurred infrequently. In Washington no follow-up surveys were conducted until 1977, although the population has been monitored closely since then (Jameson et al. 1982, 1986; Jeffries and Jameson 1995).

A comparative analysis of polybrominated diphenyl ethers and polychlorinated biphenyls in southern sea otters that died of infectious diseases and noninfectious causes

USGS Publications Warehouse

Kannan, K.; Perrota, E.; Thomas, N.J.; Aldous, D.M.

2007-01-01

Southern sea otters (Enhydra lutris nereis) from the California coast continue to exhibit a slower population regrowth rate than the population in Alaska. Infectious diseases have been identified as a frequent cause of death. Infectious diseases caused by varied pathogens including bacteria, fungi, and parasites were suggestive of compromised immunological health of mature animals in this population. To test the hypothesis that elevated exposure to immunotoxic contaminants such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) contribute to disease susceptibility via immunosuppression, we determined concentrations of PBDEs and PCBs in livers of 80 adult female sea otters that died of infectious diseases, noninfectious causes, or emaciation. Concentrations of PBDEs and PCBs in sea otter livers varied widely (10a??26,800 ng/g and 81a??210,000 ng/g, lipid weight, respectively). Concentrations of PBDEs in sea otters were some of the highest values reported for marine mammals so far. Although PCB concentrations in sea otters have declined during 1992a??2002, the mean concentration was at the threshold at which adverse health effects are elicited. Concentrations of PBDEs and PCBs were significantly correlated, suggesting co-exposure of these contaminants in sea otters. No significant association was found between the concentrations of PBDEs and the health status of sea otters. Concentrations of PCBs were significantly higher in otters in the infectious disease category than in the noninfectious category, suggesting an association between elevated PCB concentrations and infectious diseases in Southern sea otters.

Molecular characterization of Sarcocystis neurona strains from opossums (Didelphis virginiana) and intermediate hosts from Central California

PubMed Central

Rejmanek, Daniel; Miller, Melissa A.; Grigg, Michael E.; Crosbie, Paul R.; Conrad, Patricia A.

2016-01-01

Sarcocystis neurona is a significant cause of neurological disease in horses and other animals, including the threatened Southern sea otter (Enhydra lutris nereis). Opossums (Didelphis virginiana), the only known definitive hosts for S. neurona in North America, are an introduced species in California. S. neurona DNA isolated from sporocysts and/or infected tissues of 10 opossums, 6 horses, 1 cat, 23 Southern sea otters, and 1 harbor porpoise (Phocoena phocoena) with natural infections was analyzed based on 15 genetic markers, including the first internal transcribed spacer (ITS-1) region; the 25/396 marker; S. neurona surface antigen genes (snSAGs) 2, 3, and 4; and 10 different microsatellites. Based on phylogenetic analysis, most of the S. neurona strains segregated into three genetically distinct groups. Additionally, fifteen S. neurona samples from opossums and several intermediate hosts, including sea otters and horses, were found to be genetically identical across all 15 genetic markers, indicating that fatal encephalitis in Southern sea otters and equine protozoal myeloencephalitis (EPM) in horses is strongly linked to S. neurona sporocysts shed by opossums. PMID:20226596

Behavior associated with forced copulation of juvenile Pacific harbor seals (Phoca vitulina richardsi) by southern sea otters (Enhydra lutris nereis)

USGS Publications Warehouse

Harris, Heather S.; Oates, Stori C.; Staedler, Michelle M.; Tinker, M. Tim; Jessup, David A.; Harvey, James T.; Miller, Melissa A.

2010-01-01

Nineteen occurrences of interspecific sexual behavior between male southern sea otters (Enhydra lutris nereis) and juvenile Pacific harbor seals (Phoca vitulina richardsi) were reported in Monterey Bay, California, between 2000 and 2002. At least three different male sea otters were observed harassing, dragging, guarding, and copulating with harbor seals for up to 7 d postmortem. Carcasses of 15 juvenile harbor seals were recovered, and seven were necropsied in detail by a veterinary pathologist. Necropsy findings from two female sea otters that were recovered dead from male sea otters exhibiting similar behavior are also presented to facilitate a comparison of lesions. The most frequent lesions included superficial skin lacerations; hemorrhage around the nose, eyes, flippers, and perineum; and traumatic corneal erosions or ulcers. The harbor seals sustained severe genital trauma, ranging from vaginal perforation to vagino-cervical transection, and colorectal perforations as a result of penile penetration. One harbor seal developed severe pneumoperitoneum subsequent to vaginal perforation, which was also observed in both female sea otters and has been reported as a postcoital lesion in humans. This study represents the first description of lesions resulting from forced copulation of harbor seals by sea otters and is also the first report of pneu-moperitoneum secondary to forced copulation in a nonhuman animal. Possible explanations for this behavior are discussed in the context of sea otter biology and population demographics.

Ecological drivers of variation in tool-use frequency across sea otter populations

USGS Publications Warehouse

Fujii, Jessica; Ralls, Katherine; Tinker, M. Tim

2015-01-01

Sea otters are well-known tool users, employing objects such as rocks or shells to break open hard-shelled invertebrate prey. However, little is known about how the frequency of tool use varies among sea otter populations and the factors that drive these differences. We examined 17 years of observational data on prey capture and tool use from 8 sea otter populations ranging from southern California to the Aleutian Islands in Alaska. There were significant differences in the diets of these populations as well as variation in the frequency of tool use. Sea otters at Amchitka Island, Alaska, used tools on less than 1% of dives that resulted in the capture of prey compared with approximately 16% in Monterey, California. The percentage of individuals in the population that used tools ranged from 10% to 93%. In all populations, marine snails and thick-shelled bivalves were most likely to be associated with tool use, whereas soft-bodied prey items such as worms and sea stars were the least likely. The probability that a tool would be used on a given prey type varied across populations. The morphology of the prey item being handled and the prevalence of various types of prey in local diets were major ecological drivers of tool use: together they accounted for about 64% of the variation in tool-use frequency among populations. The remaining variation may be related to changes in the relative costs and benefits to an individual otter of learning to use tools effectively under differing ecological circumstances.

Temporal association between land-based runoff events and California sea otter (Enhydra lutris nereis) protozoal mortalities.

PubMed

Shapiro, Karen; Miller, Melissa; Mazet, Jonna

2012-04-01

Toxoplasma gondii and Sarcocystis neurona have caused significant morbidity and mortality in threatened Southern sea otters (Enhydra lutris nereis) along the central California coast. Because only terrestrial animals are known to serve as definitive hosts for T. gondii and S. neurona, infections in otters suggest a land to sea flow of these protozoan pathogens. To better characterize the role of overland runoff in delivery of terrestrially derived fecal pathogens to the near shore, we assessed the temporal association between indicators of runoff and the timing of sea otter deaths due to T. gondii and S. neurona. Sea otter stranding records 1998-2004, from Monterey and Estero bays were reviewed and cases identified for which T. gondii or S. neurona were determined to be a primary or contributing cause of death. Precipitation and stream flow data from both study sites were used as indicators of land-based runoff. Logistic regression was applied to determine if a temporal association could be detected between protozoal mortalities and runoff indicators that occur in the 2 mo preceding mortality events. A significant association was found between S. neurona otter deaths at Estero Bay and increased stream flow that occurred 30-60 days prior to mortality events. At this site, the cause of otter mortality following increased river flows was 12 times more likely to be S. neurona infection compared with nonprotozoal causes of death. There were no significant associations between the timing of T. gondii otter deaths and indicators of overland runoff. Our results indicate that the association between overland runoff and otter mortalities is affected by geography as well as parasite type, and highlight the complex mechanisms that influence transmission of terrestrially derived pathogens to marine wildlife. Policy and management practices that aim to mitigate discharges of contaminated overland runoff can aid conservation efforts by reducing pathogen pollution of coastal waters, which impacts the health of threatened marine wildlife and humans.

Mitogenomes and relatedness do not predict frequency of tool-use by sea otters

USGS Publications Warehouse

Ralls, Katherine; Rotzel McInerney, Nancy; Gagne, Roderick B.; Ernest, Holly B.; Tinker, M. Tim; Fujii, Jessica; Maldonado, Jesus

2017-01-01

Many ecological aspects of tool-use in sea otters are similar to those in Indo-Pacific bottlenose dolphins. Within an area, most tool-using dolphins share a single mitochondrial haplotype and are more related to each other than to the population as a whole. We asked whether sea otters in California showed similar genetic patterns by sequencing mitogenomes of 43 otters and genotyping 154 otters at 38 microsatellite loci. There were six variable sites in the mitogenome that yielded three haplotypes, one found in only a single individual. The other two haplotypes contained similar percentages (33 and 36%) of frequent tool-users and a variety of diet types. Microsatellite analyses showed that snail specialists, the diet specialist group that most frequently used tools, were no more related to each other than to the population as a whole. The lack of genetic association among tool-using sea otters compared with dolphins may result from the length of time each species has been using tools. Tool-use in dolphins appears to be a relatively recent innovation (less than 200 years) but sea otters have probably been using tools for many thousands or even millions of years.

Lesions and behavior associated with forced copulation of juvenile Pacific harbor seals (Phoca vitulina richardsi) by southern sea otters (Enhydra lutris nereis)

USGS Publications Warehouse

Harris, H.S.; Oates, S.C.; Staedler, M.M.; Tinker, M.T.; Jessup, David A.; Harvey, J.T.; Miller, M.A.

2010-01-01

Nineteen occurrences of interspecific sexual behavior between male southern sea otters (Enhydra lutris nereis) and juvenile Pacific harbor seals (Phoca vitulina richardsi) were reported in Monterey Bay, California, between 2000 and 2002. At least three different male sea otters were observed harassing, dragging, guarding, and copulating with harbor seals for up to 7 d postmortem. Carcasses of 15 juvenile harbor seals were recovered, and seven were necropsied in detail by a veterinary pathologist. Necropsy findings from two female sea otters that were recovered dead from male sea otters exhibiting similar behavior are also presented to facilitate a comparison of lesions. The most frequent lesions included superficial skin lacerations; hemorrhage around the nose, eyes, flippers, and perineum; and traumatic corneal erosions or ulcers. The harbor seals sustained severe genital trauma, ranging from vaginal perforation to vagino-cervical transection, and colorectal perforations as a result of penile penetration. One harbor seal developed severe pneumoperitoneum subsequent to vaginal perforation, which was also observed in both female sea otters and has been reported as a postcoital lesion in humans. This study represents the first description of lesions resulting from forced copulation of harbor seals by sea otters and is also the first report of pneumoperitoneum secondary to forced copulation in a nonhuman animal. Possible explanations for this behavior are discussed in the context of sea otter biology and population demographics.

Protozoal meningoencephalitis in sea otters (Enhydra lutris): A histopathological and immunohistochemical study of naturally occurring cases

USGS Publications Warehouse

Thomas, N.J.; Dubey, J.P.; Lindsay, D.S.; Cole, Rebecca A.; Meteyer, C.U.

2007-01-01

Protozoal meningoencephalitis is considered to be an important cause of mortality in the California sea otter (Enhydra lutris). Thirty nine of 344 (11.3%) California (CA) and Washington state (WA) sea otters examined from 1985 to 2004 had histopathological evidence of significant protozoal meningoencephalitis. The aetiological agents and histopathological changes associated with these protozoal infections are described. The morphology of the actively multiplicative life stages of the organisms (tachyzoites for Toxoplasma gondii and merozoites for Sarcocystis neurona) and immunohistochemical labelling were used to identify infection with S. neurona (n=22, 56.4%), T. gondii (n=5, 12.8%) or dual infection with both organisms (n=12, 30.8%). Active S. neurona was present in all dual infections, while most had only the latent form of T. gondii. In S. neuronameningoencephalitis, multifocal to diffuse gliosis was widespread in grey matter and consistently present in the molecular layer of the cerebellum. In T. gondiimeningoencephalitis, discrete foci of gliosis and malacia were more widely separated, sometimes incorporated pigment-laden macrophages and mineral, and were found predominantly in the cerebral cortex. Quiescent tissue cysts of T. gondii were considered to be incidental and not a cause of clinical disease and mortality. Protozoal meningoencephalitis was diagnosed more frequently in the expanding population of WA sea otters (10 of 31, 32.3%) than in the declining CA population (29 of 313, 9.3%). Among sea otters with protozoal meningoencephalitis, those that had displayed neurological signs prior to death had active S. neurona encephalitis, supporting the conclusion that S. neurona is the most significant protozoal pathogen in the central nervous system of sea otters.

Molecular characterization of Sarcocystis neurona strains from opossums (Didelphis virginiana) and intermediate hosts from Central California.

PubMed

Rejmanek, Daniel; Miller, Melissa A; Grigg, Michael E; Crosbie, Paul R; Conrad, Patricia A

2010-05-28

Sarcocystis neurona is a significant cause of neurological disease in horses and other animals, including the threatened Southern sea otter (Enhydra lutris nereis). Opossums (Didelphis virginiana), the only known definitive hosts for S. neurona in North America, are an introduced species in California. S. neurona DNA isolated from sporocysts and/or infected tissues of 10 opossums, 6 horses, 1 cat, 23 Southern sea otters, and 1 harbor porpoise (Phocoena phocoena) with natural infections was analyzed based on 15 genetic markers, including the first internal transcribed spacer (ITS-1) region; the 25/396 marker; S. neurona surface antigen genes (snSAGs) 2, 3, and 4; and 10 different microsatellites. Based on phylogenetic analysis, most of the S. neurona strains segregated into three genetically distinct groups. Additionally, fifteen S. neurona samples from opossums and several intermediate hosts, including sea otters and horses, were found to be genetically identical across all 15 genetic markers, indicating that fatal encephalitis in Southern sea otters and equine protozoal myeloencephalitis (EPM) in horses is strongly linked to S. neurona sporocysts shed by opossums. (c) 2010 Elsevier B.V. All rights reserved.

Activity patterns and time budgets of the declining sea otter population at Amchitka Island, Alaska

USGS Publications Warehouse

Gelatt, Thomas S.; Siniff, Donald B.; Estes, James A.

2002-01-01

Time budgets of predators may reflect population status if time spent foraging varies with local prey abun- dance. We assumed that the sea otter (Enhydra lutris) population at Amchitka Island, Alaska, USA, had been at equilibrium since the early 1960s and collected time budgets of otters to be used to represent future conditions of currently expanding sea otter populations. We used radiotelemetry to monitor activity-time budgets of otters from August 1992 to March 1994. Sea otter activity was directly linked to sex, age, weather condition, season, and time of day. Sea otters differed in percent time foraging among cohorts but not within cohorts. Percent time foraging ranged from 21% for females with very young (≤ 3weeks of age) dependent pups to 52% for females with old (≥10 weeks of age) pups. Otters foraged more and hauled out more as local sea conditions worsened. Adult males spent less time foraging during winter and spring, consistent with seasonal changes in prey selection. Time spent for- aging was similar to that reported for otters in California and an established population in Prince William Sound, Alaska, but greater than that of otters in recently established populations in Oregon and Alaska. Despite current evidence indicating that the population was in decline during our study, we were unable to recognize this change using time budgets. Our results illustrate the importance of stratifying analyses of activity patterns by age and sex cohorts and the complexity inherent in comparisons of behavioral data between different populations relying on distinct prey bases.

Comparison of human and southern sea otter (Enhydra lutris nereis) health risks for infection with protozoa in nearshore waters.

PubMed

Adell, A D; McBride, G; Wuertz, S; Conrad, P A; Smith, W A

2016-11-01

Cryptosporidium and Giardia spp. are waterborne, fecally-transmitted pathogens that cause economic loss due to gastroenteritis and beach closures. We applied quantitative microbial risk assessment (QMRA) to determine the health risks for humans and sea otters due to waterborne exposure of Cryptosporidium and Giardia spp. when swimming in three types of surface waters: river, stormwater and wastewater effluent during the wet and dry seasons in the central coast of California. This is the first application of QMRA to estimate both the probability of infection in Southern sea otters and the probability of illness in humans, using microbial source tracking (MST) as a variable. Children swimming close to stormwater discharges had an estimated Cryptosporidium-associated illness probability that exceeded the accepted U.S. EPA criteria (32 illnesses/1000 swimmers or 3.2%). Based on the assumption that sea otters are as susceptible as humans to Cryptosporidium infection, the infection probabilities were close to 2% and 16% when sea otters were swimming at the end of points of rivers and stormwater discharges, respectively. In the case of Giardia, infection probabilities of 11% and 23% were estimated for sea otters swimming at the end of point of wastewater discharges, assuming that sea otters are as susceptible as gerbils and humans, respectively. The results of this QMRA suggest that 1) humans and sea otters are at risk when swimming at outflow sites for rivers, stormwater and treated wastewater effluent; 2) reduced loads of viable protozoan cysts and oocysts in recreational water can lessen the probability of infection of humans and sea otters; and 3) the risk of infection of humans and sea otters can be reduced with the treatment of wastewater to decrease oocyst and cyst viability before effluent is released into the sea. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sea otter population structure and ecology in Alaska

USGS Publications Warehouse

Bodkin, James L.; Monson, Daniel H.

2002-01-01

Sea otters are the only fully marine otter. They share a common ancestry with the Old World land otters, but their route of dispersal to the New World is uncertain. The historic range of the species is along the northern Pacific Ocean rim, between central Baja California and the islands of northern Japan. Because they forage almost exclusively on bottom-dwelling marine invertebrates such as clams, snails, crabs, and sea urchins, they predominantly occur near shore. Their offshore distribution is limited by their diving ability; although they are capable of diving to more than 100 meters deep, most of their feeding takes place between the shoreline and depths of 40 meters. They are social animals, generally resting in protected bays or kelp forests in groups, commonly referred to as rafts. Because they are gregarious, possess a fine fur, and occur primarily near shore, they have been exploited by humans for as long as they have co-occupied coastal marine communities.During the late Pleistocene, glacial advances and retreats in the northern latitudes likely influenced genetic exchange within the sea otter’s northern range. When the glaciers were at their maximum, ice sheets extended over large coastal areas, isolating sea otter populations and causing local extinctions. During periods of glacial retreat, sea otters likely recolonized the newly available habitats, allowing exchange of individuals and gene flow between populations.Beginning in about 1750, sea otter populations underwent dramatic declines as a direct result of commercial harvest for their furs. Explorations by Vitus Bering led to the discovery of abundant sea otter populations in the Aleutian Islands. The early harvest, conducted by Russians with enslaved Aleut hunters, began in the eastern Aleutians. Eventually the harvest became multinational and contributed significantly to the exploration and settlement of the North Pacific coastline by Europeans. There were two distinct periods of harvest—one reaching its peak about 1800 and averaging about 15,000 per year and a second about 1870, averaging about 4,000 per year. The causes for this harvest pattern are unknown, but it may represent two distinct periods of overexploitation separated by a brief period of population recovery.By 1890 the species had been eliminated throughout most of its range, persisting in small numbers at 13 isolated locations in California, Alaska, and Russia. The number of sea otters that survived the fur trade is unknown, but available data suggest that some remnant populations may have been as small as a few dozen individuals. In 1911, sea otters were afforded protection under the International Fur Seal Treaty, and populations apparently responded by gradually increasing in abundance. The rates of population recovery varied among locations, averaging 9% annually and ranging from 6 to 13%. The population at Amchitka Island in the central Aleutians had the highest growth rate among those surviving, apparently reaching carrying capacity by about 1950.Efforts to aid the recovery of the species into the vast unoccupied habitats between California and Prince William Sound began in 1965. Sea otters from Amchitka and Prince William Sound were translocated to Oregon, Washington, British Columbia, and several locations in southeastern Alaska. With the exception of Oregon, these translocations have resulted in the establishment of successful colonies. Population growth rates of translocated sea otters have been significantly greater than among remnant populations, averaging 21% and ranging from 18 to 24%. We don’t know why the growth rates of the remnant and translocated populations are so different, but it may be partly because of the abundant food and space available at the translocated sites.The varying patterns of sea otter population decline and recovery provide a unique and powerful tool for studying the effects of historic reductions on populations, as well as how populations respond to varying environmental conditions. During the past decade, using molecular genetics, researchers have been trying to understand how sea otter populations might differ throughout the North Pacific and what effects population reductions and recovery have had on population genetics. Also, as a result of the varying degree of recovery among isolated populations, we have the opportunity to contrast life history attributes (such as condition, reproduction, and survival) among populations throughout their range. These contrasts may be useful in developing methods to assess the status of populations where traditional methods of surveying abundance are difficult and expensive.

Using stable isotopes to investigate individual diet specialization in California sea otters (Enhydra lutris nereis)

USGS Publications Warehouse

Newsome, S.D.; Tinker, M.T.; Monson, Daniel H.; Oftedal, O.T.; Ralls, K.; Staedler, M.M.; Fogel, M.L.; Estes, J.A.

2009-01-01

Differences in diet composition among conspecifics (dietary specialization) have been documented across a broad range of taxonomic groups and habitats, and such variation at the individual level is increasingly recognized as an important component of diversity in trophic interactions. Accurate identification of individual dietary specialization, however, requires longitudinal dietary records that are labor-intensive and cost-prohibitive to obtain for many species. Here we explore the use of stable isotopes (δ13C and δ15N) as a promising technique for detecting and quantifying patterns of individual dietary specialization. Southern sea otters (Enhydra lutris nereis) offer a unique opportunity for testing this approach because (1) they consume a wide variety of prey that span multiple trophic levels, habitats, and ecologically defined functional groups; and (2) individual diet specialization can be validated with existing observational data. We analyzed the isotopic composition of sea otter vibrissae (n = 31) in order to characterize inter- and intra-individual variation in sea otter diets at Monterey Bay, California, USA. At the population level, sea otters showed substantial variation in both δ13C and δ15N values, occupying nearly all of the “isotopic space” created by the diversity of isotopic signatures of potential prey taxa. Most of the variation in sea otter vibrissae was accounted for by differences between individuals, with much less contributed by within-individual variation. A majority of sea otters (∼80%) showed relatively little temporal variability in isotopic composition, suggesting that the proportional composition of most individuals' diets is relatively constant over time; a few individuals (∼20%) exhibited a high degree of intra-vibrissa isotopic variability, suggesting seasonal shifts in diet composition. These results and our interpretation of them were supported by long-term observational data on the diets of radio-tagged sea otters from the same population (n = 23). Our results demonstrate that stable isotopes can provide an efficient tool for measuring individual- and population-level dietary breadth and may be useful for studying populations where longitudinal data on individuals would otherwise be impossible to acquire. This will be critical for examining the causes and consequences of dietary variation within and among consumer populations, thereby improving our understanding of these important ecological and evolutionary processes at the community level.

The cost of reproduction: differential resource specialization in female and male California sea otters.

PubMed

Smith, Emma A Elliott; Newsome, Seth D; Estes, James A; Tinker, M Tim

2015-05-01

Intraspecific variation in behavior and diet can have important consequences for population and ecosystem dynamics. Here, we examine how differences in reproductive investment and spatial ecology influence individual diet specialization in male and female southern sea otters (Enhydra lutris nereis). We hypothesize that greater reproductive constraints and smaller home ranges of females lead to more pronounced intraspecific competition and increased specialization. We integrate stable carbon (δ(13)C) and nitrogen (δ(15)N) isotope analysis of sea otter vibrissae with long-term observational studies of five subpopulations in California. We define individual diet specialization as low ratios of within-individual variation (WIC) to total population niche width (TNW). We compare isotopic and observational based metrics of WIC/TNW for males and females to data on population densities, and movement patterns using both general linear and linear mixed-effects models. Consistent with our hypothesis, increasing population density is associated with increased individual diet specialization by females but not by males. Additionally, we find the amount of coastline in a sea otter's home range positively related with individual dietary variability, with increased range span resulting in weaker specialization for both males and females. We attribute our results to sex-based differences in movement, with females needing to specialize in their small ranges to maximize energy gain, and posit that the paradigm of individual prey specialization in sea otters with increased intraspecific competition may be a pattern driven largely by females. Our work highlights a potentially broader role of sex in the mechanistic pressures promoting and maintaining diet specialization.

Individual dietary specialization and dive behaviour in the California sea otter: Using archival time depth data to detect alternative foraging strategies

NASA Astrophysics Data System (ADS)

Tinker, M. T.; Costa, D. P.; Estes, J. A.; Wieringa, N.

2007-02-01

The existence of individual prey specializations has been reported for an ever-growing number of taxa, and has important ramifications for our understanding of predator-prey dynamics. We use the California sea otter population as a case study to validate the use of archival time-depth data to detect and measure differences in foraging behaviour and diet. We collected observational foraging data from radio-tagged sea otters that had been equipped with Mk9 time depth recorders (TDRs, Wildlife Computers, Redmond, WA). After recapturing the study animals and retrieving the TDRs it was possible to compare the two data types, by matching individual dives from the TDR record with observational data and thus examining behavioural correlates of capture success and prey species. Individuals varied with respect to prey selection, aggregating into one of three distinct dietary specializations. A number of TDR-derived parameters, particularly dive depth and post-dive surface interval, differed predictably between specialist types. A combination of six dive parameters was particularly useful for discriminating between specialist types, and when incorporated into a multivariate cluster analysis, these six parameters resulted in classification of 13 adult female sea otters into three clusters that corresponded almost perfectly to the diet-based classification (1 out of 13 animals was misclassified). Thus based solely on quantifiable traits of time-depth data that have been collected over an appropriate period (in this case 1 year per animal), it was possible to assign female sea otters to diet type with >90% accuracy. TDR data can thus be used as a tool to measure the degree of individual specialization in sea otter populations, a conclusion that will likely apply to other diving marine vertebrates as well. Our ultimate goals must be both to understand the causes of individual specialization, and to incorporate such variation into models of population- and community-level food web dynamics.

Individual dietary specialization and dive behaviour in the California sea otter: Using archival time-depth data to detect alternative foraging strategies

USGS Publications Warehouse

Tinker, M.T.; Costa, D.P.; Estes, J.A.; Wieringa, N.

2007-01-01

The existence of individual prey specializations has been reported for an ever-growing number of taxa, and has important ramifications for our understanding of predator-prey dynamics. We use the California sea otter population as a case study to validate the use of archival time-depth data to detect and measure differences in foraging behaviour and diet. We collected observational foraging data from radio-tagged sea otters that had been equipped with Mk9 time depth recorders (TDRs, Wildlife Computers, Redmond, WA). After recapturing the study animals and retrieving the TDRs it was possible to compare the two data types, by matching individual dives from the TDR record with observational data and thus examining behavioural correlates of capture success and prey species. Individuals varied with respect to prey selection, aggregating into one of three distinct dietary specializations. A number of TDR-derived parameters, particularly dive depth and post-dive surface interval, differed predictably between specialist types. A combination of six dive parameters was particularly useful for discriminating between specialist types, and when incorporated into a multivariate cluster analysis, these six parameters resulted in classification of 13 adult female sea otters into three clusters that corresponded almost perfectly to the diet-based classification (1 out of 13 animals was misclassified). Thus based solely on quantifiable traits of time-depth data that have been collected over an appropriate period (in this case 1 year per animal), it was possible to assign female sea otters to diet type with >90% accuracy. TDR data can thus be used as a tool to measure the degree of individual specialization in sea otter populations, a conclusion that will likely apply to other diving marine vertebrates as well. Our ultimate goals must be both to understand the causes of individual specialization, and to incorporate such variation into models of population- and community-level food web dynamics. ?? 2007 Elsevier Ltd. All rights reserved.

Expressed MHC class II genes in sea otters (Enhydra lutris) from geographically disparate populations

USGS Publications Warehouse

Bowen, Lizabeth; Aldridge, B.M.; Miles, A. Keith; Stott, J.L.

2006-01-01

The major histocompatibility complex (MHC) is central to maintaining the immunologic vigor of individuals and populations. Classical MHC class II genes were targeted for partial sequencing in sea otters (Enhydra lutris) from populations in California, Washington, and Alaska. Sequences derived from sea otter peripheral blood leukocyte mRNAs were similar to those classified as DQA, DQB, DRA, and DRB in other species. Comparisons of the derived amino acid compositions supported the classification of these as functional molecules from at least one DQA, DQB, and DRA locus and at least two DRB loci. While limited in scope, phylogenetic analysis of the DRB peptide‐binding region suggested the possible existence of distinct clades demarcated by geographic region. These preliminary findings support the need for additional MHC gene sequencing and expansion to a comprehensive study targeting additional otters.

Food abundance, prey morphology, and diet specialization influence individual sea otter tool use

USGS Publications Warehouse

Fujii, Jessica A.; Ralls, Katherine; Tinker, M. Tim

2017-01-01

Sea otters are well-known tool users, employing objects such as rocks or shells to break open invertebrate prey. We used a series of generalized linear mixed effect models to examine observational data on prey capture and tool use from 211 tagged individuals from 5 geographically defined study areas throughout the sea otter’s range in California. Our best supported model was able to explain 75% of the variation in the frequency of tool use by individual sea otters with only ecological and demographic variables. In one study area, where sea otter food resources were abundant, all individuals had similar diets focusing on preferred prey items and used tools at low to moderate frequencies (4–38% of prey captures). In the remaining areas, where sea otters were food-limited, individuals specialized on different subsets of the available prey and had a wider range of average tool-use frequency (0–98% of prey captures). The prevalence of difficult-to-access prey in individual diets was a major predictor of tool use and increased the likelihood of using tools on prey that were not difficult to access as well. Age, sex, and feeding habitat also contributed to the probability of tool use but to a smaller extent. We developed a conceptual model illustrating how food abundance, the prevalence of difficult-to-access prey, and individual diet specialization interacted to determine the likelihood that individual sea otters would use tools and considered the model’s relevance to other tool-using species.

The high cost of motherhood: End-lactation syndrome in southern sea otters (Enhydra lutris nereis) on the central California, USA, coast

USGS Publications Warehouse

Chinn, Sarah S; Miller, Melissa A.; Tinker, M. Tim; Staedler, Michelle M.; Batac, Francesca I.; Dodd, Erin M.; Henkel, Laird A.

2016-01-01

Sea otters (Enhydra lutris) have exceptionally high energetic requirements, which nearly double during lactation and pup care. Thus, females are extremely vulnerable to caloric insufficiency. Despite a number of compensatory strategies, the metabolic challenge of reproduction culminates in numerous maternal deaths annually. Massive depletion of energy reserves results in a case presentation that we define as end-lactation syndrome (ELS), characterized by moderate to severe emaciation not attributable to a concurrent, independent disease process in females dying during late pup care or postweaning. We compiled detailed data for 108 adult female southern sea otters (Enhydra lutris nereis) examined postmortem that stranded in California, US, 2005–12, and assessed pathology, reproductive status, and the location and timing of stranding. We introduce simple, grossly apparent, standardized physical criteria to assess reproductive stage for female sea otters. We also describe ELS, examine associated risk factors, and highlight female life history strategies that likely optimize reproduction and survival. Our data suggest that females can reset both the timing and energetic demands of reproduction through fetal loss, pup abandonment, or early weaning as part of specific physiologic checkpoints during each reproductive cycle. Females appear to preload nutritionally during delayed implantation and gestation to increase fitness and reproductive success. We found that ELS was a major cause of death, affecting 56% of enrolled adult females. Peak ELS prevalence occurred in late spring, possibly reflecting the population trend toward fall/winter pupping. Increasing age and number of pregnancies were associated with a higher risk of ELS. Although the proportion of ELS females was highest in areas with dense sea otter populations, cases were recovered throughout the range, suggesting that death from ELS is associated with, but not solely caused by, population resource limitation.

The distribution of nuclear genetic variation and historical demography of sea otters

USGS Publications Warehouse

Aguilar, A.; Jessup, David A.; Estes, J.; Garza, J.C.

2008-01-01

The amount and distribution of population genetic variation is crucial information for the design of effective conservation strategies for endangered species and can also be used to provide inference about demographic processes and patterns of migration. Here, we describe variation at a large number of nuclear genes in sea otters Enhydra lutris ssp. We surveyed 14 variable microsatellite loci and two genes of the major histocompatibility complex (MHC) in up to 350 California sea otters Enhydra lutris nereis, which represents ∼10% of the subspecies' population, and 46 otters from two Alaskan sites. We utilized methods for detecting past reductions in effective population size to examine the effects of near extinction from the fur trade. Summary statistic tests largely failed to find a signal of a recent population size reduction (within the past 200 years), but a Bayesian method found a signal of a strong reduction over a longer time scale (up to 500 years ago). These results indicate that the reduction in size began long enough ago that much genetic variation was lost before the 19th century fur trade. A comparison of geographic distance and pairwise relatedness for individual otters found no evidence of kin-based spatial clustering for either gender. This indicates that there is no population structure, due to extended family groups, within the California population. A survey of population genetic variation found that two of the MHC genes, DQB and DRB, had two alleles present and one of the genes, DRA, was monomorphic in otters. This contrasts with other mammals, where they are often the most variable coding genes known. Genetic variation in the sea otter is among the lowest observed for a mammal and raises concerns about the long-term viability of the species, particularly in the face of future environmental changes.

Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system

USGS Publications Warehouse

Johnson, Christine K.; Tinker, M. Tim; Estes, James A.; Conrad, Patricia A.; Staedler, Michelle M.; Miller, Melissa A.; Jessup, David A.; Mazet, Jonna A.K.

2014-01-01

The processes promoting disease in wild animal populations are highly complex, yet identifying these processes is critically important for conservation when disease is limiting a population. By combining field studies with epidemiologic tools, we evaluated the relationship between key factors impeding southern sea otter (Enhydra lutris nereis) population growth: disease and resource limitation. This threatened population has struggled to recover despite protection, so we followed radio-tagged sea otters and evaluated infection with 2 disease-causing protozoal pathogens, Toxoplasma gondii and Sarcocystis neurona, to reveal risks that increased the likelihood of pathogen exposure. We identified patterns of pathogen infection that are linked to individual animal behavior, prey choice, and habitat use. We detected a high-risk spatial cluster of S. neurona infections in otters with home ranges in southern Monterey Bay and a coastal segment near San Simeon and Cambria where otters had high levels of infection with T. gondii. We found that otters feeding on abalone, which is the preferred prey in a resource-abundant marine ecosystem, had a very low risk of infection with either pathogen, whereas otters consuming small marine snails were more likely to be infected with T. gondii. Individual dietary specialization in sea otters is an adaptive mechanism for coping with limited food resources along central coastal California. High levels of infection with protozoal pathogens may be an adverse consequence of dietary specialization in this threatened species, with both depleted resources and disease working synergistically to limit recovery.

Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system

PubMed Central

Johnson, Christine K.; Tinker, Martin T.; Estes, James A.; Conrad, Patricia A.; Staedler, Michelle; Miller, Melissa A.; Jessup, David A.; Mazet, Jonna A. K.

2009-01-01

The processes promoting disease in wild animal populations are highly complex, yet identifying these processes is critically important for conservation when disease is limiting a population. By combining field studies with epidemiologic tools, we evaluated the relationship between key factors impeding southern sea otter (Enhydra lutris nereis) population growth: disease and resource limitation. This threatened population has struggled to recover despite protection, so we followed radio-tagged sea otters and evaluated infection with 2 disease-causing protozoal pathogens, Toxoplasma gondii and Sarcocystis neurona, to reveal risks that increased the likelihood of pathogen exposure. We identified patterns of pathogen infection that are linked to individual animal behavior, prey choice, and habitat use. We detected a high-risk spatial cluster of S. neurona infections in otters with home ranges in southern Monterey Bay and a coastal segment near San Simeon and Cambria where otters had high levels of infection with T. gondii. We found that otters feeding on abalone, which is the preferred prey in a resource-abundant marine ecosystem, had a very low risk of infection with either pathogen, whereas otters consuming small marine snails were more likely to be infected with T. gondii. Individual dietary specialization in sea otters is an adaptive mechanism for coping with limited food resources along central coastal California. High levels of infection with protozoal pathogens may be an adverse consequence of dietary specialization in this threatened species, with both depleted resources and disease working synergistically to limit recovery. PMID:19164513

The cost of reproduction: differential resource specialization in female and male California sea otters

USGS Publications Warehouse

Elliott Smith, Emma A.; Newsome, Seth D.; Estes, James A.; Tinker, M. Tim

2015-01-01

Intraspecific variation in behavior and diet can have important consequences for population and ecosystem dynamics. Here, we examine how differences in reproductive investment and spatial ecology influence individual diet specialization in male and female southern sea otters (Enhydra lutris nereis). We hypothesize that greater reproductive constraints and smaller home ranges of females lead to more pronounced intraspecific competition and increased specialization. We integrate stable carbon (δ13C) and nitrogen (δ15N) isotope analysis of sea otter vibrissae with long-term observational studies of five subpopulations in California. We define individual diet specialization as low ratios of within-individual variation (WIC) to total population niche width (TNW). We compare isotopic and observational based metrics of WIC/TNW for males and females to data on population densities, and movement patterns using both general linear and linear mixed-effects models. Consistent with our hypothesis, increasing population density is associated with increased individual diet specialization by females but not by males. Additionally, we find the amount of coastline in a sea otter’s home range positively related with individual dietary variability, with increased range span resulting in weaker specialization for both males and females. We attribute our results to sex-based differences in movement, with females needing to specialize in their small ranges to maximize energy gain, and posit that the paradigm of individual prey specialization in sea otters with increased intraspecific competition may be a pattern driven largely by females. Our work highlights a potentially broader role of sex in the mechanistic pressures promoting and maintaining diet specialization.

Trade-offs between energy maximization and parental care in a central place forager, the sea otter

USGS Publications Warehouse

Thometz, N M; Staedler, M.M.; Tomoleoni, Joseph; Bodkin, James L.; Bentall, G.B.; Tinker, M. Tim

2016-01-01

Between 1999 and 2014, 126 archival time–depth recorders (TDRs) were used to examine the foraging behavior of southern sea otters (Enhydra lutris nereis) off the coast of California, in both resource-abundant (recently occupied, low sea otter density) and resource-limited (long-occupied, high sea otter density) locations. Following predictions of foraging theory, sea otters generally behaved as energy rate maximizers. Males and females without pups employed similar foraging strategies to optimize rates of energy intake in resource-limited habitats, with some exceptions. Both groups increased overall foraging effort and made deeper, longer and more energetically costly dives as resources became limited, but males were more likely than females without pups to utilize extreme dive profiles. In contrast, females caring for young pups (≤10 weeks) prioritized parental care over energy optimization. The relative importance of parental care versus energy optimization for adult females with pups appeared to reflect developmental changes as dependent young matured. Indeed, contrary to females during the initial stages of lactation, females with large pups approaching weaning once again prioritized optimizing energy intake. The increasing prioritization of energy optimization over the course of lactation was possible due to the physiological development of pups and likely driven by the energetic deficit incurred by females early in lactation. Our results suggest that regardless of resource availability, females at the end of lactation approach a species-specific ceiling for percent time foraging and that reproductive females in the central portion of the current southern sea otter range are disproportionately affected by resource limitation.

Dual congenital transmission of Toxoplasma gondii and Sarcocystis neurona in a late-term aborted pup from a chronically infected southern sea otter (Enhydra lutris nereis).

PubMed

Shapiro, Karen; Miller, Melissa A; Packham, Andrea E; Aguilar, Beatriz; Conrad, Patricia A; Vanwormer, Elizabeth; Murray, Michael J

2016-03-01

Toxoplasma gondii and Sarcocystis neurona are protozoan parasites with terrestrial definitive hosts, and both pathogens can cause fatal disease in a wide range of marine animals. Close monitoring of threatened southern sea otters (Enhydra lutris nereis) in California allowed for the diagnosis of dual transplacental transmission of T. gondii and S. neurona in a wild female otter that was chronically infected with both parasites. Congenital infection resulted in late-term abortion due to disseminated toxoplasmosis. Toxoplasma gondii and S. neurona DNA was amplified from placental tissue culture, as well as from fetal lung tissue. Molecular characterization of T. gondii revealed a Type X genotype in isolates derived from placenta and fetal brain, as well as in all tested fetal organs (brain, lung, spleen, liver and thymus). This report provides the first evidence for transplacental transmission of T. gondii in a chronically infected wild sea otter, and the first molecular and immunohistochemical confirmation of concurrent transplacental transmission of T. gondii and S. neurona in any species. Repeated fetal and/or neonatal losses in the sea otter dam also suggested that T. gondii has the potential to reduce fecundity in chronically infected marine mammals through parasite recrudescence and repeated fetal infection.

An incidence of twinning in the sea otter (Enhydra lutris)

USGS Publications Warehouse

Jameson, Ronald J.; Bodkin, James L.

1986-01-01

On 3 October 1984 at 0928 h (PST) near Pt. San Simeon, California (35°39’N, 121°11’W), we observed a female sea otter (Enhydra lutris) resting in a kelp bed (Macrocystis pyrifera) with a small pup on her chest;  approximately 2 m away another small pup floated unattended in the kelp. The only other otters we saw in the area was a mated pair (adult male tending an adult female) resting about 20 m from the mother and pups. At 0929 h the mother swam to the unattended pup and placed it on her abdomen next to the other pup. We concluded that live birth of twin pups had occurred, an incident previously unrecorded for the species.

Southern sea otter range expansion and habitat use in the Santa Barbara Channel, California

USGS Publications Warehouse

Tinker, M. Tim; Tomoleoni, Joseph; LaRoche, Nicole; Bowen, Lizabeth; Miles, A. Keith; Murray, Mike; Staedler, Michelle; Randell, Zachary

2017-01-17

The re-colonization of the Santa Barbara channel by sea otters brings these ESA-listed marine mammals closer to active oil and gas production facilities, shipping lanes and naturally occurring oil and gas seeps. However, the degree to which sea otters may actually be affected by human-caused oil spills or exposure to natural oil seeps is currently unknown. Between 2012 and 2014, the U.S. Geological Survey and collaborating agencies conducted a telemetry-based study of sea otters in Santa Barbara channel, in order to provide critical information for resource managers (specifically the Bureau of Ocean Energy Management, henceforth BOEM, and the U.S. Fish and Wildlife Service, henceforth USFWS) about the spatial ecology, population status, and potential population threats to sea otters in Santa Barbara Channel, with particular reference to exposure to manmade structures and sources of oil and natural gas. Analysis of spatial monitoring data using a Bayesian-based synoptic model allowed for description of sea otter home ranges, identification of hot-spots of use, and insights into habitat selection behavior by male and female sea otters. Important findings included the deeper modal depth preferred by males versus females, strong preferences by both sexes for areas with persistent kelp canopy, and greater use of soft-sediment areas by males. The synoptic model also provided the ability to predict population-level density distribution for each sex in new habitats: by calculating the value of these probability density distributions at the known locations of natural seeps, we were able to identify those seeps with higher potential for sea otter encounters. The relative probability of occurrence at locations near to some seeps was sufficiently high (about 1% likelihood of occurrence for some of our study animals) that one would anticipate occasional encounters. Data on male and female survival, reproductive success, activity budgets, and body condition all indicated that sea otters in Santa Barbara Channel are not resource limited, and thus we would expect to see continued strong population growth in this area. However, the principal cause of death for study animals was lethal bites by white sharks, suggesting that shark bite mortality represents the single biggest threat to continued population growth in the Santa Barbara Channel.

Rehabilitating sea otters: Feeling good versus being effective; Chapter 20

USGS Publications Warehouse

Estes, James A.; Tinker, M. Tim; Kareiva, Peter; Marvier, Michelle; Silliman, Brian

2017-01-01

This chapter examines the complexities of assessing the merits and drawbacks of wildlife rehabilitation. Wildlife rehabilitation is often costly, and the resulting benefits differ depending on whether one’s interest is in the welfare of individual animals or conserving populations. Two examples of this dilemma include the rehabilitation of oiled sea otters following the Exxon Valdez spill in Prince William Sound, Alaska, and the rehabilitation of stranded sea otter pups in central California. In the first example, substantial financial investment resulted in little or no benefits for population conservation. In the second example, the potential for population-level benefits is context dependent: in populations near carrying capacity the conservation impacts are negligible, whereas in isolated, low-density populations rehabilitation and release can be an effective conservation tool. Wildlife rehabilitation is valued by people for various reasons, but recognizing and acknowledging the difference between individual and population welfare is an important step toward effective wildlife conservation.

Energetic demands of immature sea otters from birth to weaning: implications for maternal costs, reproductive behavior and population-level trends

USGS Publications Warehouse

Thometz, N.M.; Tinker, M.T.; Staedler, M.M.; Mayer, K.A.; Williams, T.M.

2014-01-01

Sea otters (Enhydra lutris) have the highest mass-specific metabolic rate of any marine mammal, which is superimposed on the inherently high costs of reproduction and lactation in adult females. These combined energetic demands have been implicated in the poor body condition and increased mortality of female sea otters nearing the end of lactation along the central California coast. However, the cost of lactation is unknown and currently cannot be directly measured for this marine species in the wild. Here, we quantified the energetic demands of immature sea otters across five developmental stages as a means of assessing the underlying energetic challenges associated with pup rearing that may contribute to poor maternal condition. Activity-specific metabolic rates, daily activity budgets and field metabolic rates (FMR) were determined for each developmental stage. Mean FMR of pre-molt pups was 2.29±0.81 MJ day−1 and increased to 6.16±2.46 and 7.41±3.17 MJ day−1 in post-molt pups and dependent immature animals, respectively. Consequently, daily energy demands of adult females increase 17% by 3 weeks postpartum and continue increasing to 96% above pre-pregnancy levels by the average age of weaning. Our results suggest that the energetics of pup rearing superimposed on small body size, marine living and limited on-board energetic reserves conspire to make female sea otters exceptionally vulnerable to energetic shortfalls. By controlling individual fitness, maternal behavior and pup provisioning strategies, this underlying metabolic challenge appears to be a major factor influencing current population trends in southern sea otters (Enhydra lutris nereis).

77 FR 27246 - Marine Mammal Protection Act; Stock Assessment Report

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-09

... population status in the southern sea otter: a comparative study between central California and San Nicolas.... Kannan, K., E. Perrotta, N.J. Thomas, and K.M. Aldous. 2007. A comparative analysis of polybrominated... OCS Study 2006-007. Coastal Research Center, Marine Science Institute, University of California, Santa...

Sea Otter, River Otter. The Wonder Series.

ERIC Educational Resources Information Center

Robinson, Sandra Chisholm

This curriculum guide is all about otters and provides information on both sea and river otters. Included are activities related to the diet of sea otters, the adaptations sea otters have made to live in the sea, their tool-using abilities, where they live and how to spot them, comparative anatomy of sea and river otters, and otter movement. The…

Genetic diversity among sea otter isolates of Toxoplasma gondii

USGS Publications Warehouse

Sundar, N.; Cole, Rebecca A.; Thomas, N.J.; Majumdar, D.; Dubey, J.P.; Su, C.

2008-01-01

Sea otters (Enhydra lutris) have been reported to become infected with Toxoplasma gondiiand at times succumb to clinical disease. Here, we determined genotypes of 39 T. gondiiisolates from 37 sea otters in two geographically distant locations (25 from California and 12 from Washington). Six genotypes were identified using 10 PCR-RFLP genetic markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico, and by DNA sequencing of loci SAG1 and GRA6 in 13 isolates. Of these 39 isolates, 13 (33%) were clonal Type II which can be further divided into two groups at the locus Apico. Two of the 39 isolates had Type II alleles at all loci except a Type I allele at locus L358. One isolate had Type II alleles at all loci except the Type I alleles at loci L358 and Apico. One isolate had Type III alleles at all loci except Type II alleles at SAG2 and Apico. Two sea otter isolates had a mixed infection. Twenty-one (54%) isolates had an unique allele at SAG1 locus. Further genotyping or DNA sequence analysis for 18 of these 21 isolates at loci SAG1 and GRA6 revealed that there were two different genotypes, including the previously identified Type X (four isolates) and a new genotype named Type A (14 isolates). The results from this study suggest that the sea otter isolates are genetically diverse.

Causes of mortality in California sea otters during periods of population growth and decline

USGS Publications Warehouse

Estes, J.A.; Hatfield, B.B.; Ralls, K.; Ames, J.

2003-01-01

Elevated mortality appears to be the main reason for both sluggish growth and periods of decline in the threatened California sea otter population. We assessed causes of mortality from salvage records of 3,105 beach-cast carcasses recovered from 1968 through 1999, contrasting two periods of growth with two periods of decline. Overall, an estimated 40%-60% of the deaths were not recovered and 70% of the recovered carcasses died from unknown causes. Nonetheless, several common patterns were evident in the salvage records during the periods of population decline. These included greater percentages of (1) prime age animals (3-10 yr), (2) carcasses killed by great white shark attacks, (3) carcasses recovered in spring and summer, and (4) carcasses for which the cause of death was unknown. Neither sex composition nor the proportion of carcasses dying of infectious disease varied consistently between periods of population increase and decline. The population decline from 1976 to 1984 was likely due to incidental mortality in a set-net fishery, and the decline from 1995 to 1999 may be related to a developing live-fish fishery. Long-term trends unrelated to periods of growth and decline included a decrease in per capita pup production and mass/length ratios of adult carcasses over the 31-yr study. The generally high proportion of deaths from infectious disease suggests that this factor has contributed to the chronically sluggish growth rate of the California sea otter population.

Osteosarcoma of the maxilla with concurrent osteoma in a southern sea otter (Enhydra lutris nereis)

USGS Publications Warehouse

Fernandez, J. Rodriguez-Ramos; Thomas, N.J.; Dubielzig, R.R.; Drees, R.

2012-01-01

Southern sea otters (Enhydra lutris nereis) are threatened marine mammals that belong to the family Mustelidae and are native to the coast of Central California. Neoplasia is reported infrequently in seaotters. An adult female free-ranging southern sea otter was found alive at Pebble Beach, Monterey County, California, on January 1st, 1994 and died soon after capture. The carcass was submitted to the US Geological Survey – National Wildlife Health Center for necropsy examination. Grossly, a mass with rubbery texture was firmly attached to the left maxillary region of the skull and the nasopharynx was occluded by soft neoplastic tissue. Post-mortem skull radiographs showed an oval, smoothly marginated mineralized opaque mass centered on the left maxilla, extending from the canine tooth to caudal to the molar and replacing portions of the zygomatic arch and palatine and temporal bones. The majority of the mass protruded laterally from the maxilla and was characterized by central homogeneous mineral opacity. Microscopically, the mass was characterized by fully differentiated lamellar non-osteonal bone that expanded beyond the margins of the adjacent normal osteonal bone. Sections of the nasopharyngeal mass were comprised of moderately pleomorphic cells with bony stroma. Gross, microscopical and radiological findings were compatible with maxillary osteosarcoma with concurrent osteoma.

California sea otter (Enhydra lutris nereis) census results, Spring 2016

USGS Publications Warehouse

Tinker, M. Tim; Hatfield, Brian B.

2016-09-19

The 2016 census of southern sea otters Enhydra lutris nereis was conducted in May along the mainland coast of central California and in April at San Nicolas Island in southern California. The 3-year average of combined counts from the mainland range and San Nicolas Island was 3,272. This is the first year that the official index has exceeded 3,090, the Endangered Species Act delisting threshold suggested by the U.S. Fish and Wildlife Service (the threshold would need to be exceeded for 3 consecutive years before delisting consideration). The 5-year average trend in abundance, including both the mainland range and San Nicolas Island populations, is positive at 3.2 percent per year; however, regional trends vary, with localized declines at the southern and northern peripheries of the mainland range. The lack of population growth in the range peripheries over recent years likely explains the cessation of range expansion, with the range limits remaining almost unchanged from the previous 5 years.

Toxoplasma gondii, source to sea: higher contribution of domestic felids to terrestrial parasite loading despite lower infection prevalence.

PubMed

Vanwormer, Elizabeth; Conrad, Patricia A; Miller, Melissa A; Melli, Ann C; Carpenter, Tim E; Mazet, Jonna A K

2013-09-01

Environmental transmission of Toxoplasma gondii, a global zoonotic parasite, adversely impacts human and animal health. Toxoplasma is a significant cause of mortality in threatened Southern sea otters, which serve as sentinels for disease threats to people and animals in coastal environments. As wild and domestic felids are the only recognized hosts capable of shedding Toxoplasma oocysts into the environment, otter infection suggests land-to-sea pathogen transmission. To assess relative contributions to terrestrial parasite loading, we evaluated infection and shedding among managed and unmanaged feral domestic cats, mountain lions, and bobcats in coastal California, USA. Infection prevalence differed among sympatric felids, with a significantly lower prevalence for managed feral cats (17%) than mountain lions, bobcats, or unmanaged feral cats subsisting on wild prey (73-81%). A geographic hotspot of infection in felids was identified near Monterey Bay, bordering a high-risk site for otter infection. Increased odds of oocyst shedding were detected in bobcats and unmanaged feral cats. Due to their large populations, pet and feral domestic cats likely contribute more oocysts to lands bordering the sea otter range than native wild felids. Continued coastal development may influence felid numbers and distribution, increase terrestrial pathogens in freshwater runoff, and alter disease dynamics at the human-animal-environment interface.

Using molecular epidemiology to track Toxoplasma gondii from terrestrial carnivores to marine hosts: implications for public health and conservation.

PubMed

VanWormer, Elizabeth; Miller, Melissa A; Conrad, Patricia A; Grigg, Michael E; Rejmanek, Daniel; Carpenter, Tim E; Mazet, Jonna A K

2014-01-01

Environmental transmission of the zoonotic parasite Toxoplasma gondii, which is shed only by felids, poses risks to human and animal health in temperate and tropical ecosystems. Atypical T. gondii genotypes have been linked to severe disease in people and the threatened population of California sea otters. To investigate land-to-sea parasite transmission, we screened 373 carnivores (feral domestic cats, mountain lions, bobcats, foxes, and coyotes) for T. gondii infection and examined the distribution of genotypes in 85 infected animals sampled near the sea otter range. Nested PCR-RFLP analyses and direct DNA sequencing at six independent polymorphic genetic loci (B1, SAG1, SAG3, GRA6, L358, and Apico) were used to characterize T. gondii strains in infected animals. Strains consistent with Type X, a novel genotype previously identified in over 70% of infected sea otters and four terrestrial wild carnivores along the California coast, were detected in all sampled species, including domestic cats. However, odds of Type X infection were 14 times higher (95% CI: 1.3-148.6) for wild felids than feral domestic cats. Type X infection was also linked to undeveloped lands (OR = 22, 95% CI: 2.3-250.7). A spatial cluster of terrestrial Type II infection (P = 0.04) was identified in developed lands bordering an area of increased risk for sea otter Type II infection. Two spatial clusters of animals infected with strains consistent with Type X (P ≤ 0.01) were detected in less developed landscapes. Differences in T. gondii genotype prevalence among domestic and wild felids, as well as the spatial distribution of genotypes, suggest co-existing domestic and wild T. gondii transmission cycles that likely overlap at the interface of developed and undeveloped lands. Anthropogenic development driving contact between these cycles may increase atypical T. gondii genotypes in domestic cats and facilitate transmission of potentially more pathogenic genotypes to humans, domestic animals, and wildlife.

Changes in sea urchins and kelp following a reduction in sea otter density as a result of the Exxon Valdez oil spill

USGS Publications Warehouse

Dean, Thomas A.; Bodkin, James L.; Jewett, Stephen C.; Monson, Daniel H.; Jung, D.

2000-01-01

Interactions between sea otters Enhydra lutris, sea urchins Strongylocentrotus droebachiensis, and kelp were investigated following the reduction in sea otter density in Prince William Sound, Alaska, after the Exxon Valdez oil spill in 1989. At northern Knight Island, a heavily oiled portion of the sound, sea otter abundance was reduced by a minimum of 50% by the oil spill, and from 1995 through 1998 remained at an estimated 66% lower than in 1973. Where sea otter densities were reduced, there were proportionally more large sea urchins. However, except in some widely scattered aggregations, both density and biomass of sea urchins were similar in an area of reduced sea otter density compared with an area where sea otters remained about 10 times more abundant. Furthermore, there was no change in kelp abundance in the area of reduced sea otter density. This is in contrast to greatly increased biomass of sea urchins and greatly reduced kelp density observed following an approximate 90% decline in sea otter abundance in the western Aleutian Islands. The variation in community response to a reduction in sea otters may be related to the magnitude of the reduction and the non-linear response by sea urchins to changes in predator abundance. The number of surviving sea otters may have been high enough to suppress sea urchin populations in Prince William Sound, but not in the Aleutians. Alternatively, differences in response may have been due to differences in the frequency or magnitude of sea urchin recruitment. Densities of small sea urchins were much higher in the Aleutian system even prior to the reduction in sea otters, suggesting a higher rate of recruitment.

Changes in Alaskan soft-bottom prey communities along a gradient in sea otter predation

USGS Publications Warehouse

Kvitek, R.G.; Oliver, J.S.; DeGange, A.R.; Anderson, B.S.

1992-01-01

Sea Otter (Enhydra lutris), well documented as "keystone" predators in rocky marine communities, were found to exert a strong influence on infaunal prey communities in soft-sediment habitats. Direct and indirect effects of sea otter predation on subtidal soft-bottom prey communities were evaluated along a temporal gradient of sea otter occupancy around the Kodiak Archipelago. The results indicate that Kodiak otters forage primarily on bivalve prey and dramatically reduce infaunal bivalve and green sea urchin (Strongylocentrotus droebachiensis) prey populations. Bivalve prey abundance, biomass, and size were inversely related to duration of sea otter occupancy. The relative conditions of shells discarded by otters in shallow (<10 m) vs. deep (> 20 m) water at the same sites indicate that otters first exploited Saxidomus in shallow-water feeding areas, and later switched to Macoma spp. in deeper water. Otter-cracked shells of the deep-burrowing clam Tresus capax were rarely found, even at otter foraging sites where the clam accounted for the majority of available prey biomass, suggesting that it has a partial depth refuge from otter predation. The indirect effects of otter predation included substratum disturbance and the facilitation of sea star predation on infaunal prey. Sea stars, Pycnopodia helianthoides, were attracted to experimentally dug excavations as well as natural sea otter foraging pits, where the sea stars foraged on smaller size classes of infaunal bivalves than those eaten by otters. Otters also discard clam shells on the sediment surface and expose old, buried shells during excavation. Surface shells were found to provide attachment sites for large anemones and kelp. Our study shows that sea otters can affect soft-sediment communities, not only through predation, as in rocky habitats, but also through disturbance, and thus retain a high degree of influence in two very different habitat types.

A protozoal-associated epizootic impacting marine wildlife: Mass-mortality of southern sea otters (Enhydra lutris nereis) due to Sarcocystis neurona infection

PubMed Central

Conrad, Patricia A.; Harris, Michael; Hatfield, Brian; Langlois, Gregg; Jessup, David A.; Magargal, Spencer L.; Packham, Andrea E.; Toy-Choutka, Sharon; Melli, Ann C.; Murray, Michael A.; Gulland, Frances M.; Grigg, Michael E.

2016-01-01

During April, 2004, 40 sick and dead southern sea otters (Enhydra lutris nereis) were recovered over 18 km of coastline near Morro Bay, California. This event represented the single largest monthly spike in mortality ever recorded during 30 years of southern sea otter stranding data collection. Because of the point-source nature of the event and clinical signs consistent with severe, acute neurological disease, exposure to a chemical or marine toxin was initially considered. However, detailed postmortem examinations revealed lesions consistent with an infectious etiology, and further investigation confirmed the protozoan parasite Sarcocystis neurona as the underlying cause. Tissues from 94% of examined otters were PCR-positive for S. neurona, based on DNA amplification and sequencing at the ITS-1 locus, and 100% of tested animals (n = 14) had elevated IgM and IgG titers to S. neurona. Evidence to support the point-source character of this event include the striking spatial and temporal clustering of cases and detection of high concentrations of anti-S. neurona IgM in serum of stranded animals. Concurrent exposure to the marine biotoxin domoic acid may have enhanced susceptibility of affected otters to S. neurona and exacerbated the neurological signs exhibited by stranded animals. Other factors that may have contributed to the severity of this epizootic include a large rainstorm that preceded the event and an abundance of razor clams near local beaches, attracting numerous otters close to shore within the affected area. This is the first report of a localized epizootic in marine wildlife caused by apicomplexan protozoa. PMID:20615616

A protozoal-associated epizootic impacting marine wildlife: mass-mortality of southern sea otters (Enhydra lutris nereis) due to Sarcocystis neurona infection.

PubMed

Miller, Melissa A; Conrad, Patricia A; Harris, Michael; Hatfield, Brian; Langlois, Gregg; Jessup, David A; Magargal, Spencer L; Packham, Andrea E; Toy-Choutka, Sharon; Melli, Ann C; Murray, Michael A; Gulland, Frances M; Grigg, Michael E

2010-09-20

During April 2004, 40 sick and dead southern sea otters (Enhydra lutris nereis) were recovered over 18km of coastline near Morro Bay, California. This event represented the single largest monthly spike in mortality ever recorded during 30 years of southern sea otter stranding data collection. Because of the point-source nature of the event and clinical signs consistent with severe, acute neurological disease, exposure to a chemical or marine toxin was initially considered. However, detailed postmortem examinations revealed lesions consistent with an infectious etiology, and further investigation confirmed the protozoan parasite Sarcocystis neurona as the underlying cause. Tissues from 94% of examined otters were PCR-positive for S. neurona, based on DNA amplification and sequencing at the ITS-1 locus, and 100% of tested animals (n=14) had elevated IgM and IgG titers to S. neurona. Evidence to support the point-source character of this event include the striking spatial and temporal clustering of cases and detection of high concentrations of anti-S. neurona IgM in serum of stranded animals. Concurrent exposure to the marine biotoxin domoic acid may have enhanced susceptibility of affected otters to S. neurona and exacerbated the neurological signs exhibited by stranded animals. Other factors that may have contributed to the severity of this epizootic include a large rainstorm that preceded the event and an abundance of razor clams near local beaches, attracting numerous otters close to shore within the affected area. This is the first report of a localized epizootic in marine wildlife caused by apicomplexan protozoa.

19 CFR 12.63 - Seal-skin or sea-otter-skin waste.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 1 2014-04-01 2014-04-01 false Seal-skin or sea-otter-skin waste. 12.63 Section... OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.63 Seal-skin or sea-otter-skin waste. Seal-skin or sea-otter-skin waste composed of small pieces not large enough to be...

19 CFR 12.61 - Fur-seal or sea-otter skins permitted entry.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 1 2011-04-01 2011-04-01 false Fur-seal or sea-otter skins permitted entry. 12.61...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.61 Fur-seal or sea-otter skins permitted entry. (a) Fur-seal or sea-otter skins taken by Indians, Aleuts, or other...

19 CFR 12.63 - Seal-skin or sea-otter-skin waste.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 1 2013-04-01 2013-04-01 false Seal-skin or sea-otter-skin waste. 12.63 Section... OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.63 Seal-skin or sea-otter-skin waste. Seal-skin or sea-otter-skin waste composed of small pieces not large enough to be...

19 CFR 12.63 - Seal-skin or sea-otter-skin waste.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 1 2012-04-01 2012-04-01 false Seal-skin or sea-otter-skin waste. 12.63 Section... OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.63 Seal-skin or sea-otter-skin waste. Seal-skin or sea-otter-skin waste composed of small pieces not large enough to be...

19 CFR 12.61 - Fur-seal or sea-otter skins permitted entry.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Fur-seal or sea-otter skins permitted entry. 12.61...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.61 Fur-seal or sea-otter skins permitted entry. (a) Fur-seal or sea-otter skins taken by Indians, Aleuts, or other...

19 CFR 12.63 - Seal-skin or sea-otter-skin waste.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 1 2011-04-01 2011-04-01 false Seal-skin or sea-otter-skin waste. 12.63 Section... OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.63 Seal-skin or sea-otter-skin waste. Seal-skin or sea-otter-skin waste composed of small pieces not large enough to be...

19 CFR 12.63 - Seal-skin or sea-otter-skin waste.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Seal-skin or sea-otter-skin waste. 12.63 Section... OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.63 Seal-skin or sea-otter-skin waste. Seal-skin or sea-otter-skin waste composed of small pieces not large enough to be...

19 CFR 12.61 - Fur-seal or sea-otter skins permitted entry.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 1 2013-04-01 2013-04-01 false Fur-seal or sea-otter skins permitted entry. 12.61...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.61 Fur-seal or sea-otter skins permitted entry. (a) Fur-seal or sea-otter skins taken by Indians, Aleuts, or other...

19 CFR 12.61 - Fur-seal or sea-otter skins permitted entry.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 1 2012-04-01 2012-04-01 false Fur-seal or sea-otter skins permitted entry. 12.61...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.61 Fur-seal or sea-otter skins permitted entry. (a) Fur-seal or sea-otter skins taken by Indians, Aleuts, or other...

19 CFR 12.61 - Fur-seal or sea-otter skins permitted entry.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 1 2014-04-01 2014-04-01 false Fur-seal or sea-otter skins permitted entry. 12.61...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.61 Fur-seal or sea-otter skins permitted entry. (a) Fur-seal or sea-otter skins taken by Indians, Aleuts, or other...

Detection and characterization of diverse coccidian protozoa shed by California sea lions.

PubMed

Girard, Yvette A; Johnson, Christine K; Fritz, Heather M; Shapiro, Karen; Packham, Andrea E; Melli, Ann C; Carlson-Bremer, Daphne; Gulland, Frances M; Rejmanek, Daniel; Conrad, Patricia A

2016-04-01

Tissue-cyst forming coccidia in the family Sarcocystidae are etiologic agents of protozoal encephalitis in marine mammals including the federally listed Southern sea otter (Enhydra lutris). California sea lions (Zalophus californianus), whose coastal habitat overlaps with sea otters, are definitive hosts for coccidian protozoa provisionally named Coccidia A, B and C. While Coccidia A and B have unknown clinical effects on aquatic wildlife hosts, Coccidia C is associated with severe protozoal disease in harbor seals (Phoca vitulina). In this study, we conducted surveillance for protozoal infection and fecal shedding in hospitalized and free-ranging California sea lions on the Pacific Coast and examined oocyst morphology and phenotypic characteristics of isolates via mouse bioassay and cell culture. Coccidia A and B were shed in similar frequency, particularly by yearlings. Oocysts shed by one free-ranging sea lion sampled at Año Nuevo State Park in California were previously unidentified in sea lions and were most similar to coccidia infecting Guadalupe fur seals (Arctocephalus townsendi) diagnosed with protozoal disease in Oregon (USA). Sporulated Coccidia A and B oocysts did not replicate in three strains of mice or in African green monkey kidney cells. However, cultivation experiments revealed that the inoculum of fecally-derived Coccidia A and B oocysts additionally contained organisms with genetic and antigenic similarity to Sarcocystis neurona; despite the absence of detectable free sporocysts in fecal samples by microscopic examination. In addition to the further characterization of Coccidia A and B in free-ranging and hospitalized sea lions, these results provide evidence of a new role for sea lions as putative mechanical vectors of S. neurona, or S. neurona-like species. Future work is needed to clarify the distribution, taxonomical status, and pathogenesis of these parasites in sea lions and other marine mammals that share their the near-shore marine environment.

Detection and characterization of diverse coccidian protozoa shed by California sea lions

PubMed Central

Girard, Yvette A.; Johnson, Christine K.; Fritz, Heather M.; Shapiro, Karen; Packham, Andrea E.; Melli, Ann C.; Carlson-Bremer, Daphne; Gulland, Frances M.; Rejmanek, Daniel; Conrad, Patricia A.

2015-01-01

Tissue-cyst forming coccidia in the family Sarcocystidae are etiologic agents of protozoal encephalitis in marine mammals including the federally listed Southern sea otter (Enhydra lutris). California sea lions (Zalophus californianus), whose coastal habitat overlaps with sea otters, are definitive hosts for coccidian protozoa provisionally named Coccidia A, B and C. While Coccidia A and B have unknown clinical effects on aquatic wildlife hosts, Coccidia C is associated with severe protozoal disease in harbor seals (Phoca vitulina). In this study, we conducted surveillance for protozoal infection and fecal shedding in hospitalized and free-ranging California sea lions on the Pacific Coast and examined oocyst morphology and phenotypic characteristics of isolates via mouse bioassay and cell culture. Coccidia A and B were shed in similar frequency, particularly by yearlings. Oocysts shed by one free-ranging sea lion sampled at Año Nuevo State Park in California were previously unidentified in sea lions and were most similar to coccidia infecting Guadalupe fur seals (Arctocephalus townsendi) diagnosed with protozoal disease in Oregon (USA). Sporulated Coccidia A and B oocysts did not replicate in three strains of mice or in African green monkey kidney cells. However, cultivation experiments revealed that the inoculum of fecally-derived Coccidia A and B oocysts additionally contained organisms with genetic and antigenic similarity to Sarcocystis neurona; despite the absence of detectable free sporocysts in fecal samples by microscopic examination. In addition to the further characterization of Coccidia A and B in free-ranging and hospitalized sea lions, these results provide evidence of a new role for sea lions as putative mechanical vectors of S. neurona, or S. neurona-like species. Future work is needed to clarify the distribution, taxonomical status, and pathogenesis of these parasites in sea lions and other marine mammals that share their the near-shore marine environment. PMID:27141438

Evaluation of sea otter capture after the Exxon Valdez oil spill, Prince William Sound, Alaska

USGS Publications Warehouse

Bodkin, James L.; Weltz, F.; Bayha, Keith; Kormendy, Jennifer

1990-01-01

After the T/V Exxon Valdez oil spill into Prince William Sound, the U.S. Fish and Wildlife Service and Exxon Company, U.S.A., began rescuing sea otters (Enhydra lutris). The primary objective of this operation was to capture live, oiled sea otters for cleaning and rehabilitation. Between 30 March and 29 May 1989, 139 live sea otters were captured in the sound and transported to rehabilitation centers in Valdez, Alaska. Within the first 15 days of capture operations, 122 (88%) otters were captured. Most sea otters were captured near Knight, Green, and Evans islands in the western sound. The primary capture method consisted of dipnetting otters out of water and off beaches. While capture rates declined over time, survival of captured otters increased as the interval from spill date to capture date increased. The relative degree of oiling observed for each otter captured declined over time. Declining capture rates led to the use of tangle nets. The evidence suggests the greatest threat to sea otters in Prince William Sound occurred within the first 3 weeks after the spill. Thus, in the future, the authors believe rescue efforts should begin as soon as possible after an oil spill in sea otter habitat. Further, preemptive capture and relocation of sea otters in Prince William Sound may have increased the number of otters that could have survived this event.

Discovery of the fossil otter Enhydritherium terraenovae (Carnivora, Mammalia) in Mexico reconciles a palaeozoogeographic mystery.

PubMed

Tseng, Z Jack; Pacheco-Castro, Adolfo; Carranza-Castañeda, Oscar; Aranda-Gómez, José Jorge; Wang, Xiaoming; Troncoso, Hilda

2017-06-01

The North American fossil otter Enhydritherium terraenovae is thought to be partially convergent in ecological niche with the living sea otter Enhydra lutris , both having low-crowned crushing teeth and a close association with marine environments. Fossil records of Enhydritherium are found in mostly marginal marine deposits in California and Florida; despite presence of very rich records of fossil terrestrial mammals in contemporaneous localities inland, no Enhydritherium fossils are hitherto known in interior North America. Here we report the first occurrence of Enhydritherium outside of Florida and California, in a land-locked terrestrial mammal fauna of the upper Miocene deposits of Juchipila Basin, Zacatecas State, Mexico. This new occurrence of Enhydritherium is at least 200 km from the modern Pacific coastline, and nearly 600 km from the Gulf of Mexico. Besides providing further evidence that Enhydritherium was not dependent on coastal marine environments as originally interpreted, this discovery leads us to propose a new east-to-west dispersal route between the Florida and California Enhydritherium populations through central Mexico. The proximity of the fossil locality to nearby populations of modern neotropical otters Lontra longicaudis suggests that trans-Mexican freshwater corridors for vertebrate species in riparian habitats may have persisted for a prolonged period of time, pre-dating the Great American Biotic Interchange. © 2017 The Author(s).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monnett, C.; Rotterman, L.M.

Ninety-six adult female sea otters and 64 weanling sea otters were instrumented with implanted radio-transmitters in Prince William Sound during 1989-1990 and monitored until November, 1991. Observations of the movements of adult female and weanling sea otters in prince William Sound indicated no tendency for individuals to emigrate from, or immigrate to, the area affected by oil spilled from the Exxon Valdez. This finding indicates that the study groups of sea otters categorized as `western Prince William Sound oil-spill treatment` otters and `eastern Prince William Sound control` otters are indeed distinct groups of individuals. No tendency was observed for recentlymore » weaned sea otters to exhibit a preference for habitat units based on the likelihood that they would encounter spilled oil therein. Finally, data reported suggest that the recovery of the sea otter population in the oil spill affected region of Prince William Sound will likely be a direct function of the rates of survival and reproduction of the sea otters in the affected habitat with little or no influence from emigration or immigration.« less

Procedures and rationale for marking sea otters captured and treated during the T/V Exxon Valdez oil spill

USGS Publications Warehouse

DeGange, A.R.; Williams, T.D.; Bayha, Keith; Kormendy, Jennifer

1990-01-01

Four methods were used for marking sea otters (Enhydra lutris) captured and treated during the response to the T/V Exxon Valdez oil spill. Colored and numbered flipper tags were placed on each sea otter that was brought to the otter treatment centers. These tags allowed individual recognition and permitted the tracking of individuals through the treatment and holding processes. Recovery of tagged carcasses may provide a crude measure of the fates of rehabilitated otters. Seven sea otters were instrumented with radio transmitters attached to flipper tags as part of a pilot release program. The results of that study were inconclusive. Forty-five sea otters were implanted with radio transmitters as part of a study to assess the fate of rehabilitated sea otters. Specific objectives of the study include estimating survived rates and monitoring the reproductive success of the sample of rehabilitated sea otters and comparing the results with similar variables in a control population. Transponder chips were injected in the perianal region of all but seven of the instrumented sea otters, and all were tagged with red flipper tags. The advantages and disadvantages of each type of tag are discussed.

A protozoal-associated epizootic impacting marine wildlife: Mass-mortality of southern sea otters (Enhydra lutris nereis) due to Sarcocystis neurona infection

USGS Publications Warehouse

Miller, M.A.; Conrad, P.A.; Harris, M.; Hatfield, B.; Langlois, G.; Jessup, David A.; Magargal, S.L.; Packham, A.E.; Toy-Choutka, S.; Melli, A.C.; Murray, M.A.; Gulland, F.M.; Grigg, M.E.

2010-01-01

During April 2004, 40 sick and dead southern sea otters (Enhydra lutris nereis) were recovered over 18 km of coastline near Morro Bay, California. This event represented the single largest monthly spike in mortality ever recorded during 30 years of southern sea otter stranding data collection. Because of the point-source nature of the event and clinical signs consistent with severe, acute neurological disease, exposure to a chemical or marine toxin was initially considered. However, detailed postmortem examinations revealed lesions consistent with an infectious etiology, and further investigation confirmed the protozoan parasite Sarcocystis neurona as the underlying cause. Tissues from 94% of examined otters were PCR-positive for S. neurona, based on DNA amplification and sequencing at the ITS-1 locus, and 100% of tested animals (n= 14) had elevated IgM and IgG titers to S. neurona. Evidence to support the point-source character of this event include the striking spatial and temporal clustering of cases and detection of high concentrations of anti- S. neurona IgM in serum of stranded animals. Concurrent exposure to the marine biotoxin domoic acid may have enhanced susceptibility of affected otters to S. neurona and exacerbated the neurological signs exhibited by stranded animals. Other factors that may have contributed to the severity of this epizootic include a large rainstorm that preceded the event and an abundance of razor clams near local beaches, attracting numerous otters close to shore within the affected area. This is the first report of a localized epizootic in marine wildlife caused by apicomplexan protozoa. ?? 2010 Elsevier B.V.

An overview of sea otter studies

USGS Publications Warehouse

Ballachey, Brenda E.; Bodkin, James L.; DeGange, Anthony R.; Loughlin, Thomas R.

1994-01-01

The Exxron Valdez oil spill (EVOS) on 24 March 1989 threatened extensive areas of prime sea otter (Enhydra lutris) habitat along the coasts of south-central Alaska. The spill occurred in northeastern Prince William Sound (PWS), and oil moved rapidly south and west through PWS into the Gulf of Alaska. Much of the coastline of western PWS was heavily oiled, and the slick eventually spread as far southwest as Kodiak Island and the Alaska Peninsula (Galt and Payton 1990; Morris and Loughlin, Chapter 1). All coastal waters affected by the spill were inhabited by sea otters.Concern for the survival of sea otters following the oil spill was immediate and well founded. Sea otters are particularly vulnerable to oil contamination because they rely on pelage rather than blubber for insulation, and oiling drastically reduces the insulative value of the fur (Costa and Kooyman 1982; Siniff et al. 1982; Geraci and Williams 1990). Within days of the spill, recovery of oiled live otters and carcasses began. During the several months following the spill, sea otters became symbolic of the mortality associated with the spilled oil, and of the hope for rescue and recovery of injured wildlife (Batten 1990).An extensive sea otter rescue and rehabilitation effort was mounted in the weeks and months following the spill. Handling and treatment of the captive sea otters posed an enormous and difficult challenge, given the large number of otters held at the facilities and minimal prior experience in caring for oiled sea otters. Rehabilitation of sea otters was a separate effort from the postspill studies designed to evaluate injury to the otter populations and is not addressed in this chapter only as it relates to evaluation of damage assessment studies. Detailed information on the rehabilitation effort is presented in Bayha and Kormendy (1990) and Williams and Davis (1990).Sea otters retained a high profile in the Natural Resource Damage Assessment (NRDA) studies largely because the initial injury to the sea otter population was readily demonstrable, but also because of concerns about long-term damages. The scope of the postspill studies to assess oil-related damages to sea otters was extensive: From 1989 through 1993, more than $3,000,000 was spent, and more than 20 scientists were involved in a comprehensive research program. The studies were predominantly directed at sea otter populations in PWS.Damages to sea otters generally can be classified as either acute, defined as spill-related deaths occurring during the spill, or chronic, defined as longer term lethal or sublethal oil-related injuries. Studies of acute damages focused on estimating the total initial loss of sea otters. Characterization of the pathologies associated with exposure to oil was a secondary goal of studies of acute effects. Chronic or longer term damages may have resulted from sublethal initial exposure or continued exposure to hydrocarbons persisting in the environment. Studies of chronic effects included evaluating abundance and distribution, survival and reproduction rates, foraging behavior, and pathological, physiological, and toxicological changes in the years following the spill.The objective of this chapter is to review the studies conducted on sea otters in response to the EVOS and to synthesize the major findings of those studies relative to injury to the sea otter population associated with exposure to oil. We also provide recommendations for research to improve our understanding of the effects of future oil spills on Sea otter populations.

Individual variation in prey selection by sea otters: Patterns, causes and implications

USGS Publications Warehouse

Estes, J.A.; Riedman, M.L.; Staedler, M.M.; Tinker, M.T.; Lyon, B.E.

2003-01-01

1. Longitudinal records of prey selection by 10 adult female sea otters on the Monterey Peninsula, California, from 1983 to 1990 demonstrate extreme inter-individual variation in diet. Variation in prey availability cannot explain these differences as the data were obtained from a common spatial-temporal area. 2. Individual dietary patterns persisted throughout our study, thus indicating that they are life-long characteristics. 3. Individual dietary patterns in sea otters appear to be transmitted along matrilines, probably by way of learning during the period of mother-young association. 4. Efficient utilization of different prey types probably requires radically different sensory/motor skills, each of which is difficult to acquire and all of which may exceed the learning and performance capacities of any single individual. This would explain the absence of generalists and inertia against switching, but not the existence of alternative specialists. 5. Such individual variation might arise in a constant environment from frequency-dependent effects, whereby the relative benefit of a given prey specialization depends on the number of other individuals utilizing that prey. Additionally, many of the sea otter's prey fluctuate substantially in abundance through time. This temporal variation, in conjunction with matrilineal transmission of foraging skills, may act to mediate the temporal dynamics of prey specializations. 6. Regardless of the exact cause, such extreme individual variation in diet has broad ramifications for population and community ecology. 7. The published literature indicates that similar patterns occur in many other species.

U.S. Geological Survey (USGS), Western Region: Coastal ecosystem responses to influences from land and sea, Coastal and Ocean Science

USGS Publications Warehouse

Bodkin, James L.

2010-01-01

Sea otters and the nearshore ecosystems they inhabit-from highly urbanized California to relatively pristine Alaska-are the focus of a new multidisciplinary study by scientists with the U.S. Geological Survey (USGS) and a suite of international, academic and government collaborators. The Coastal Ecosystem Responses to Influences from Land and Sea project will investigate the many interacting variables that influence the health of coastal ecosystems along the Northeast Pacific shore. These ecosystems face unprecedented challenges, with threats arising from the adjacent oceans and lands. From the ocean, challenges include acidification, sea level rise, and warming. From the land, challenges include elevated biological, geological and chemical pollutants associated with burgeoning human populations along coastlines. The implications of these challenges for biological systems are only beginning to be explored. Comparing sea otter population status indicators from around the northeastern Pacific Rim, will begin the process of defining factors of coastal ecosystem health in this broad region.

Distribution and relative abundance of sea otters in south-central and south-western Alaska before or at the time of the T/V Exxon Valdez oil spill

USGS Publications Warehouse

DeGange, Anthony R.; Monson, Daniel H.; Irons, David B.; Robbins, C.M.; Douglas, David C.; Bayha, Keith; Kormendy, Jennifer

1990-01-01

Surveys of sea otters (Enhydra lutris) conducted before, immediately after, or at the time of the TA^ Exxon Valdez oil spill were used to guide otter capture efforts and assess the immediate effects of the spill. Shoreline counts (by boat) of sea otters in Prince William Sound in 1984 suggested that a minimum of 4,500 sea otters inhabited nearshore waters of Prince William Sound. Areas of highest density within the western portion of Prince William Sound included the Bainbridge Island area, Montague Island, Green Island, and Port Wells. About 1,330 sea otters were counted from helicopters along the coast of the Kenai Peninsula. Highest densities of sea otters were found along the western end of the Kenai Peninsula. At Kodiak Island, about 3,500 sea otters were counted in coastal surveys from helicopters. Highest densities of sea otters were found in Perenosa Bay in northern Afognak Island, and in waters between Afogneik, Kodiak, and Raspberry Islands. Along the Alaska Peninsula, about 6,500 sea otters were counted between Kamishak Bay and Unimak Pass. Areas of concentration included the Izembek Lagoon airea. False Pass, the Pavlof Islands, Hallo Bay, and Kujulik Bay. Line transect surveys conducted offshore of the coastal strips indicate that at the time of the surveys relatively high densities of sea otters existed offshore at Kodiak Island and along the Alaska Peninsula, but not on the Kenai Peninsula.

76 FR 68393 - Endangered and Threatened Wildlife and Plants; Termination of the Southern Sea Otter...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-04

... the Southern Sea Otter Translocation Program; Revised Draft Supplemental Environmental Impact Statement on the Translocation of Southern Sea Otters AGENCY: Fish and Wildlife Service, Interior. ACTION... draft supplemental environmental impact statement on the translocation of southern sea otters (revised...

Using Molecular Epidemiology to Track Toxoplasma gondii from Terrestrial Carnivores to Marine Hosts: Implications for Public Health and Conservation

PubMed Central

VanWormer, Elizabeth; Miller, Melissa A.; Conrad, Patricia A.; Grigg, Michael E.; Rejmanek, Daniel; Carpenter, Tim E.; Mazet, Jonna A. K.

2014-01-01

Background Environmental transmission of the zoonotic parasite Toxoplasma gondii, which is shed only by felids, poses risks to human and animal health in temperate and tropical ecosystems. Atypical T. gondii genotypes have been linked to severe disease in people and the threatened population of California sea otters. To investigate land-to-sea parasite transmission, we screened 373 carnivores (feral domestic cats, mountain lions, bobcats, foxes, and coyotes) for T. gondii infection and examined the distribution of genotypes in 85 infected animals sampled near the sea otter range. Methodology/Principal Findings Nested PCR-RFLP analyses and direct DNA sequencing at six independent polymorphic genetic loci (B1, SAG1, SAG3, GRA6, L358, and Apico) were used to characterize T. gondii strains in infected animals. Strains consistent with Type X, a novel genotype previously identified in over 70% of infected sea otters and four terrestrial wild carnivores along the California coast, were detected in all sampled species, including domestic cats. However, odds of Type X infection were 14 times higher (95% CI: 1.3–148.6) for wild felids than feral domestic cats. Type X infection was also linked to undeveloped lands (OR = 22, 95% CI: 2.3–250.7). A spatial cluster of terrestrial Type II infection (P = 0.04) was identified in developed lands bordering an area of increased risk for sea otter Type II infection. Two spatial clusters of animals infected with strains consistent with Type X (P≤0.01) were detected in less developed landscapes. Conclusions Differences in T. gondii genotype prevalence among domestic and wild felids, as well as the spatial distribution of genotypes, suggest co-existing domestic and wild T. gondii transmission cycles that likely overlap at the interface of developed and undeveloped lands. Anthropogenic development driving contact between these cycles may increase atypical T. gondii genotypes in domestic cats and facilitate transmission of potentially more pathogenic genotypes to humans, domestic animals, and wildlife. PMID:24874796

77 FR 67302 - Endangered and Threatened Wildlife and Plants; Termination of the Southern Sea Otter...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-09

... the Southern Sea Otter Translocation Program; Final Supplemental Environmental Impact Statement on the Translocation of Southern Sea Otters AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice of availability... Supplemental Environmental Impact Statement on the Translocation of Southern Sea Otters (final SEIS). The final...

Otters, Marine

USGS Publications Warehouse

Estes, James A.; Bodkin, James L.; Ben-David, M.; Perrin, William F.; Würsing, Bernd; Thewissen, J.G.M.

2009-01-01

The otters (Mustelidae; Lutrinae) provide an exceptional perspective into the evolution of marine living by mammals. Most extant marine mammals (e.g. the cetaceans, pinnipeds, and sirenians) have been so highly modified by long periods of selection for life in the sea that they bear little resemblance to their terrestrial ancestors. Marine otters, in contrast, are more recent expatriates from freshwater habitats and some species still live in both environments. Contrasts among species within the otters, and among the otters, terrestrial mammals, and the more highly adapted pinnipeds and cetaceans provide powerful insights into mammalian adaptations to life in the sea (Estes, 1989). Among the marine mammals, sea otters (Enhydra lutris, Fig. 1) provide the clearest understanding of consumer-induced effects on ecosystem function. This is due in part to opportunities provided by history and in part to the relative ease with which shallow coastal systems where sea otters live can be observed and studied. Although more difficult to study than sea otters, other otter species reveal the connectivity among the marine, freshwater, and terrestrial systems. These three qualities of the otters – their comparative biology, their role as predators, and their role as agents of ecosystem connectivity – are what make them interesting to marine mammalogy.The following account provides a broad overview of the comparative biology and ecology of the otters, with particular emphasis on those species or populations that live in the sea. Sea otters are features prominently, in part because they live exclusively in the sea whereas other otters have obligate associations with freshwater and terrestrial environments (Kenyon, 1969; Riedman and Estes, 1990).

Detection of sea otters in boat-based surveys of Prince William Sound, Alaska

USGS Publications Warehouse

Udevitz, Mark S.; Bodkin, James L.; Costa, Daniel P.

1995-01-01

Boat-based surveys have been commonly used to monitor sea otter populations, but there has been little quantitative work to evaluate detection biases that may affect these surveys. We used ground-based observers to investigate sea otter detection probabilities in a boat-based survey of Prince William Sound, Alaska. We estimated that 30% of the otters present on surveyed transects were not detected by boat crews. Approximately half (53%) of the undetected otters were missed because the otters left the transects, apparently in response to the approaching boat. Unbiased estimates of detection probabilities will be required for obtaining unbiased population estimates from boat-based surveys of sea otters. Therefore, boat-based surveys should include methods to estimate sea otter detection probabilities under the conditions specific to each survey. Unbiased estimation of detection probabilities with ground-based observers requires either that the ground crews detect all of the otters in observed subunits, or that there are no errors in determining which crews saw each detected otter. Ground-based observer methods may be appropriate in areas where nearly all of the sea otter habitat is potentially visible from ground-based vantage points.

Prevalence and risk factors associated with Sarcocystis neurona infections in opossums (Didelphis virginiana) from central California.

PubMed

Rejmanek, Daniel; Vanwormer, Elizabeth; Miller, Melissa A; Mazet, Jonna A K; Nichelason, Amy E; Melli, Ann C; Packham, Andrea E; Jessup, David A; Conrad, Patricia A

2009-12-03

Sarcocystis neurona, a protozoal parasite shed by opossums (Didelphis virginiana), has been shown to cause significant morbidity and mortality in horses, sea otters, and other marine mammals. Over the course of 3 years (fall 2005-summer 2008), opossums from central California were tested for infection with S. neurona. Of 288 opossums sampled, 17 (5.9%) were infected with S. neurona based on the molecular characterization of sporocysts from intestinal scrapings or feces. Risk factors evaluated for association with S. neurona infection in opossums included: age, sex, location, season, presence of pouch young in females, concomitant infection, and sampling method (live-trapped or traffic-killed). Multivariate logistic regression analysis identified that opossums in the Central Valley were 9 times more likely to be infected than those near the coast (p=0.009). Similarly, opossum infection was 5 times more likely to be detected during the reproductive season (March-July; p=0.013). This first investigation of S. neurona infection prevalence and associated risk factors in opossums in the western United States can be used to develop management strategies aimed at reducing the incidence of S. neurona infections in susceptible hosts, including horses and threatened California sea otters (Enhydra lutris neries).

Sea Otter Enhydra lutris

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.

1997-01-01

The sea otter, Enhydra lutris, is the largest member of the Mustelidae family and is the only one which lives entirely in marine waters. Sea otters are unique among marine mammals because, unlike whales, dolphins and seals, they do not have a layer of fat or blubber to keep them warm in the cool oceans of the North Pacific. Instead, sea otters depend on dense fur that traps tiny air bubbles to insulate them from the cold water. To stay warm, they also must maintain a very high metabolic rate, requiring the sea otter to eat about 25% of its body weight per day. Sea otters eat mostly invertebrates - clams, crabs, urchins, and mussels - found in shallow coastal waters.

PCB exposure in sea otters and harlequin ducks in relation to history of contamination by the Exxon Valdez oil spill

USGS Publications Warehouse

Ricca, Mark A.; Miles, A. Keith; Ballachey, Brenda E.; Bodkin, James L.; Esler, Daniel N.; Trust, Kimberly A.

2010-01-01

Exposure to contaminants other than petroleum hydrocarbons could confound interpretation of Exxon Valdez oil spill effects on biota at Prince William Sound, Alaska. Hence, we investigated polychlorinated biphenyls (PCBs) in blood of sea otters and harlequin ducks sampled during 1998. PCB concentrations characterized by lower chlorinated congeners were highest in sea otters from the unoiled area, whereas concentrations were similar among harlequin ducks from the oiled and unoiled area. Blood enzymes often elevated by xenobiotics were not related to PCB concentrations in sea otters. Only sea otters from the unoiled area had estimated risk from PCBs, and PCB composition or concentrations did not correspond to reported lower measures of population performance in sea otters or harlequin ducks from the oiled area. PCBs probably did not influence limited sea otter or harlequin duck recovery in the oiled area a decade after the spill.

Food limitation and the recovery of sea otters following the 'Exxon Valdez' oil spill

USGS Publications Warehouse

Dean, Thomas A.; Bodkin, James L.; Fukuyama, Allan K.; Jewett, Stephen C.; Monson, Daniel H.; O'Clair, Charles E.; VanBlaricom, Glenn R.

2002-01-01

We examined the potential role of food limitation in constraining the recovery of sea otters Enhydra lutris in Prince William Sound, Alaska, following the 'Exxon Valdez' oil spill. The spill resulted in the removal of a large number of sea otters in 1989, and as of 1998, the portion of the population in the heavily oiled northern Knight Island region had not fully recovered. Between 1996 and 1998, prey consumption rate was higher and the condition of sea otters was better at northern Knight Island than in an unoiled area of the sound (Montague Island). Estimates of prey energy available per unit mass of sea otter were about 4 times higher at Knight than Montague Island, albeit not significantly different between the 2 areas. Over this same period, the number of sea otters remained constant at northern Knight Island but increased at Montague Island. These data suggest that food was at least as abundant at Knight than at Montague Island, and that recovery of sea otters via intrinsic population growth was limited by factors other than food. However, the availability of food, the prey consumption rate, and the condition of sea otters were all much lower at both Knight and Montague Islands than in areas newly occupied by sea otters where the population growth rate was near the theoretical maximum. It is possible that the relatively short supply of food (compared to areas where sea otter population growth rate was high) may have inhibited immigration or interacted with other factors (e.g. oil-induced mortality or predation) to restrict sea otter population growth. Nonetheless, these data suggest that impacts of anthropogenic disturbances on large, often food-limited vertebrate predators can persist in spite of the availability of food resources that are sufficient for intrinsic population growth.

75 FR 30428 - Receipt of Applications for Permit

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-01

... from museum specimens of mantled howler monkey (Alouatta palliata) and Yellow-tail woolly monkey...), northern sea otters (Enhydra lutris kenyoni) and southern sea otters (Enhydra lutris nereis) may be... acquire, import, and export unlimited number of specimens of sea otters (Enhydra lutris), marine otters...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodkin, J.L.; Udevitz, M.S.

The authors developed an analytical model (intersection model) to estimate the exposure of sea otters (Enhydra lutris), to oil from the Exxon Valdez oil spill. The authors applied estimated and assumed exposure dependent mortality rates to the Kenai Peninsula sea otter population to provide examples of the application of the model in estimating sea otter mortality. The intersection model requires three distinct types of data: (1) distribution, abundance, and movements of oil, (2) abundance and distribution of sea otters, and (3) sea otter mortality rates relative to oil exposure. Initial output of the model is an estimate of exposure ofmore » otters to oil. Exposure is measured in amount and duration of oil near an otter`s observed location (intersections). The authors provide two examples of the model using different assumptions about the relation between exposure and mortality. Because of an apparent non-linear relation between the degree of oiling and survival of otters from rehabilitation, output from the authors` examples are likely biased.« less

Status and Trends of Sea Otter Populations in Southeast Alaska, 1969-2003

USGS Publications Warehouse

Esslinger, George G.; Bodkin, James L.

2009-01-01

Aerial surveys of all known sea otter (Enhydra lutris) habitat in Southeast Alaska (SE AK) in 2002-2003 indicated a population size of 8,949 otters [Standard Error (SE) = 899] at an average density of 0.92 otters per square kilometer. These findings on sea otter distribution and abundance were compared to results from several previous surveys. Sea otters have expanded their range beyond the outer coast of SE AK and currently occupy inside waters such as Glacier Bay and Sumner Strait. This range expansion, along with archeological evidence, supports the hypothesis that sea otters are capable of colonizing inside waters in SE AK. Inside Glacier Bay National Park and Preserve, in northern SE AK, sea otter abundance has increased from 5 in 1995 to 1,266 (SE = 196) in 2002, more than doubling on an average annual basis, indicating immigration and reproduction as factors contributing to population growth. In the remainder of northern SE AK, the estimated abundance has declined from 2,295 in 1987 to 1,838 (SE = 307) in 2002. In southern SE AK, the abundance of sea otters increased from 2,167 in 1988 to 5,845 (SE = 821) in 2003. Overall, population growth rates for sea otters in SE AK between 1987 and 2003 are much lower than rates from previous studies and were unexpected given the amount of unoccupied habitat available in SE AK. Divergent population trajectories were evident between the southern (6.6 percent per year) and northern areas of SE AK (2.0 percent per year). These differences suggest variation in reproductive or survival rates between the areas. Harvest levels between 1989 and 2003 may have had a measurable effect on sea otter populations in SE AK. Available data on age and sex specific fecundity and survival rates could be used to develop age- and sex-structured population matrix models to help guide management and conservation of sea otter populations.

Hydrocarbon concentrations and patterns in free-ranging sea otters (Enhydra lutris) from British Columbia, Canada.

PubMed

Harris, Kate A; Nichol, Linda M; Ross, Peter S

2011-10-01

With oil pollution recognized as a major threat to British Columbia's recovering sea otter (Enhydra lutris) population, it is important to distinguish acute from chronic exposures to oil constituent groups in this marine mammal. Concentrations and patterns of alkanes and polycyclic aromatic hydrocarbons (PAHs) were determined in blood samples from 29 live-captured sea otters in two coastal areas of British Columbia, as well as in representative samples of their invertebrate prey. Hydrocarbon concentrations in sea otters were similar between areas and among age and sex classes, suggesting that metabolism dominates the fate of these compounds in sea otters. Biomagnification factors derived from PAH ratios in otter:prey supported this notion. Although some higher alkylated three- and four-ring PAHs appeared to biomagnify, the majority of PAHs did not. The apparent retention of alkyl PAHs was reflected in the composition of estimated sea otter body burdens, which provided an alternative way of evaluating hydrocarbon exposure. Alkyl PAHs made up 86 ± 9% of estimated body burdens (4,340 ± 2,950 µg), with no differences between males and females (p = 0.18). The importance of measuring both parent and alkyl PAHs is underscored by their divergent dynamics in sea otters, with ready depuration of parent PAHs (metabolized or excreted) by sea otters on the one hand and biomagnification of alkyl PAHs on the other. Copyright © 2011 SETAC.

Postrelease monitoring of radio-instrumented sea otters in Prince William Sound

USGS Publications Warehouse

Monnett, C.; Rotterman, L.M.; Stack, C.; Monson, Daniel H.; Bayha, Keith; Kormendy, Jennifer

1990-01-01

Sea otters (Enhydra lutris) that were captured in western Prince William Sound (PWS) or the Gulf of Alaska, treated, and held in captivity at the temporary rehabilitation centers established in response to the T/V Exxon Valdez oil spill were instrumented with radio transmitters, released into eastern PWS, and monitored by radiotelemetry. We undertook the present study to gain information for guiding the release of the remaining captive otters and evaluating the efficacy of sea otter rehabilitation after exposure to crude oil. Radio transmitters were attached to the flippers of seven sea otters released in May 1989 and monitored for periods of a few hours to more than 60 days. However, little was learned about the fate of these animals because the radio transmitters used proved unreliable. Forty-five additional sea otters from the rehabilitation centers were implanted with radio transmitters, released into northeastern PWS and monitored for 8 months. During the first 20 days after the first release of these implanted otters (n = 21), they were more mobile than wild-caught and released sea otters studied in PWS, from 1984 through 1990. All were alive and vigorous at the end of the 20-day period. Tracking of all 45 implanted sea otters during the 8-month period showed that the otters remained highly mobile. Many (46.6%) crossed into western PWS. However, by the end of the 8 months, 12 of the instrumented otters were dead and 9 were missing. One radio failed. These mortality and missing rates are much higher than those normally observed for adult sea otters in PWS. The death rate was highest in winter. These data suggest that, despite the tremendous amount of money and energy directed toward the treatment and care of these animals, the sea otters released from the centers were not completely rehabilitated, that is, not returned to a normal state. We recommend that future policies focus on preventing otters from becoming oiled, rather than attempting to treat them after oiling has occurred. This focus is especially recommended because of stress and disease risks associated with bringing wild animals into captivity.

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

USGS Publications Warehouse

Esslinger, George G.; Esler, Daniel N.; Howlin, S.; Starcevich, L.A.

2015-06-25

After many decades of absence from southeast Alaska, sea otters (Enhydra lutris) are recolonizing parts of their former range, including Glacier Bay, Alaska. Sea otters are well known for structuring nearshore ecosystems and causing community-level changes such as increases in kelp abundance and changes in the size and number of other consumers. Monitoring population status of sea otters in Glacier Bay will help park researchers and managers understand and interpret sea otter-induced ecosystem changes relative to other sources of variation, including potential human-induced impacts such as ocean acidification, vessel disturbance, and oil spills. This report was prepared for the National Park Service (NPS), Southeast Alaska Inventory and Monitoring Network following a request for evaluation of options for monitoring sea otter population status in Glacier Bay National Park and Preserve. To meet this request, we provide a detailed consideration of the primary method of assessment of abundance and distribution, aerial surveys, including analyses of power to detect interannual trends and designs to reduce variation around annual abundance estimates. We also describe two alternate techniques for evaluating sea otter population status—(1) quantifying sea otter diets and energy intake rates, and (2) detecting change in ages at death. In addition, we provide a brief section on directed research to identify studies that would further our understanding of sea otter population dynamics and effects on the Glacier Bay ecosystem, and provide context for interpreting results of monitoring activities.

Sea otters in captivity: applications and implications of husbandry development, public display, scientific research and management, and rescue and rehabilitation for sea otter conservation

USGS Publications Warehouse

VanBlaricom, Glenn R.; Belting, Traci F.; Triggs, Lisa H.

2015-01-01

Studies of sea otters in captivity began in 1932, producing important insights for conservation. Soviet (initiated in 1932) and United States (1951) studies provided information on captive otter husbandry, setting the stage for eventual large-scale translocations as tools for population restoration. Early studies also informed effective housing of animals in zoos and aquaria, with sea otters first publicly displayed in 1954. Surveys credited displayed otters in convincing the public of conservation values. After early studies, initial scientific data for captive sea otters in aquaria came from work initiated in 1956, and from dedicated research facilities beginning in 1968. Significant achievements have been made in studies of behavior, physiology, reproduction, and high-priority management issues. Larger-scale projects involving translocation and oil spill response provided extensive insights into stress reactions, water quality issues in captivity, and effects of oil spills.

Overview of studies to determine injury caused by the Exxon Valdez Oil Spill to marine mammals

USGS Publications Warehouse

Loughlin, Thomas R.; Ballachey, Brenda E.; Wright, B.A.; Rice, S.D.; Spies, R.B.; Wolfe, D.A.; Wright, B.A.

1996-01-01

Marine mammal damage assessment studies after the Exxon Valdez oil spill concentrated on sea otters, harbor seals, Steller sea lions, killer whales, and humpback whales. Sea otter and harbor seals were the most affected marine mammal; it was estimated that several thousand otters and several hundred harbor seals died within months of the spill. Steller sea lion, harbor seal, and sea otter numbers were monitored using aerial surveys. Studies of humpback whales and killer whales used photoidentification techniques to determine changes in abundance, distribution, mortality, and natality. Tissues from animals found dead in spill and control areas were analyzed for hydrocarbon levels. Sea otters, sea lions and harbor seals had elevated hydrocarbon levels, but only sea otters and harbor seals showed population declines associated with the spill. Humpback whales were not severely affected by the Exxon Valdez oil spill. Killer whale numbers in the resident AB pod declined after the spill. Coincidental evidence supports the oil spill as the causative agent.

Limited effects of a keystone species: Trends of sea otters and kelp forests at the Semichi Islands, Alaska

USGS Publications Warehouse

Konar, Brenda

2000-01-01

Sea otters are well known as a keystone species because of their ability to transform sea urchin-dominated communities into kelp-dominated communities by preying on sea urchins and thus reducing the intensity of herbivory. After being locally extinct for more than a century, sea otters re-colonized the Semichi Islands in the Aleutian Archipelago, Alaska in the early 1990s. Here, otter populations increased to about 400 individuals by 1994, but rapidly declined to about 100 by 1997. Roughly 7 yr after initial otter re-colonization, there were only marginal changes in sea urchin biomass, mean maximum test size, and kelp density. These small changes may be the first steps in the cascading effects on community structure typically found with the invasion of a keystone species. However, no wholesale change in community structure occurred following re-colonization and growth of the sea otter population. Instead, this study describes a transition state and identifies factors such as keystone species density and residence time that can be important in dictating the degree to which otter effects are manifested.

Quantifying long-term risks to sea otters from the 1989 'Exxon Valdez' oil spill: reply to Harwell & Gentile (2013)

USGS Publications Warehouse

Ballachey, Brenda E.; Bodkin, James L.; Monson, Daniel H.

2013-01-01

Recovery of sea otter populations in Prince William Sound (PWS), Alaska, has been delayed for more than 2 decades following the 1989 ‘Exxon Valdez’ oil spill. Harwell & Gentile (2013; Mar Ecol Prog Ser 488:291–296) question our conclusions in Bodkin et al. (2012; Mar Ecol Prog Ser 447:273-287) regarding adverse effects that oil lingering in the environment may have on sea otters. They agree that exposure may continue, but disagree that it constitutes a significant risk to sea otters. In Bodkin et al. (2012), we suggested that subtle effects of chronic exposure were the most reasonable explanation for delayed recovery of the sea otter population in areas of western PWS, where shorelines were most heavily oiled. Here, we provide additional information on the ecology of sea otters that clarifies why the toxicological effects of oral ingestion of oil do not reflect all effects of chronic exposure. The full range of energetic, behavioral, and toxicological concerns must be considered to appraise how chronic exposure to residual oil may constrain recovery of sea otter populations.

SPORULATION AND SURVIVAL OF TOXOPLASMA GONDII OOCYSTS IN SEA WATER

EPA Science Inventory

Since 1992, we have been collaborating in studies on southern sea otters (Enhdyra lutris nereis) as part of a program to define factors which may be responsible for limiting the growth of the southern sea otter population. We previously demonstrated Toxoplasma gondii in sea otter...

Gene transcript profiling in sea otters post-Exxon Valdez oil spill: A tool for marine ecosystem health assessment

USGS Publications Warehouse

Bowen, Lizabeth; Miles, A. Keith; Ballachey, Brenda E.; Waters, Shannon C.; Bodkin, James L.

2016-01-01

Using a panel of genes stimulated by oil exposure in a laboratory study, we evaluated gene transcription in blood leukocytes sampled from sea otters captured from 2006–2012 in western Prince William Sound (WPWS), Alaska, 17–23 years after the 1989 Exxon Valdez oil spill (EVOS). We compared WPWS sea otters to reference populations (not affected by the EVOS) from the Alaska Peninsula (2009), Katmai National Park and Preserve (2009), Clam Lagoon at Adak Island (2012), Kodiak Island (2005) and captive sea otters in aquaria. Statistically, sea otter gene transcript profiles separated into three distinct clusters: Cluster 1, Kodiak and WPWS 2006–2008 (higher relative transcription); Cluster 2, Clam Lagoon and WPWS 2010–2012 (lower relative transcription); and Cluster 3, Alaska Peninsula, Katmai and captive sea otters (intermediate relative transcription). The lower transcription of the aryl hydrocarbon receptor (AHR), an established biomarker for hydrocarbon exposure, in WPWS 2010–2012 compared to earlier samples from WPWS is consistent with declining hydrocarbon exposure, but the pattern of overall low levels of transcription seen in WPWS 2010–2012 could be related to other factors, such as food limitation, pathogens or injury, and may indicate an inability to mount effective responses to stressors. Decreased transcriptional response across the entire gene panel precludes the evaluation of whether or not individual sea otters show signs of exposure to lingering oil. However, related studies on sea otter demographics indicate that by 2012, the sea otter population in WPWS had recovered, which indicates diminishing oil exposure.

Histopathologic lesions in sea otters exposed to crude oil

USGS Publications Warehouse

Lipscomb, T.P.; Harris, R.K.; Moeller, R.B.; Pletcher, J.M.; Haebler, R.J.; Ballachey, Brenda E.

1993-01-01

Following the Exxon Valdez oil spill in Prince William Sound, Alaska, sea otters (Enhydra lutris) that appeared to be contaminated with oil, that were in danger of becoming contaminated, or that were behaving abnormally were captured and taken to rehabilitation centers. Exposure to oil was assessed by visual examination when otters arrived at the centers. Degree of oil exposure was graded according to the following criteria: oil covering greater than 60% of the body - heavily contaminated; oil covering 30–60% of the body - moderately contaminated; oil covering less than 30% of the body or light sheen on fur - lightly contaminated. If there was no oil visible, otters were considered uncontaminated. Tissues from 51 oil-contaminated sea otters (14 males, 37 females) and from six uncontaminated sea otters (three males, three females) that died in rehabilitation centers were examined histologically. Among oil-contaminated sea otters, 19/46 had interstitial pulmonary emphysema, 13/40 had gastric erosion and hemorrhage, 11/47 had centrilobular hepatic necrosis, 14/47 had periportal to diffuse hepatic lipidosis, and 10/42 had renal tubular lipidosis. Of the uncontaminated sea otters, 1/6 had gastric erosion and hemorrhage and 1/6 had diffuse hepatic lipidosis. Histologic examinations were performed on tissues from five sea otters (three males, two females) found dead with external oil present 15 to 16 days after the spill. Periportal hepatic lipidosis and renal tubular lipidosis were found in 3/5, and interstitial pulmonary emphysema was found in 1/5. Tissues from six apparently normal sea otters (four males, two females) collected from an area not affected by an oil spill were examined histologically, and none of these lesions were found. We conclude that interstitial pulmonary emphysema, centrilobular hepatic necrosis, and hepatic and renal lipidosis of sea otters were associated with exposure to crude oil. Gastric erosion and hemorrhage may have been associated with stress of captivity and/or oil exposure.

ENDEMIC INFECTION OF STRANDED SOUTHERN SEA OTTERS (ENHYDRA LUTRIS NEREIS) WITH NOVEL PARVOVIRUS, POLYOMAVIRUS, AND ADENOVIRUS.

PubMed

Siqueira, Juliana D; Ng, Terry F; Miller, Melissa; Li, Linlin; Deng, Xutao; Dodd, Erin; Batac, Francesca; Delwart, Eric

2017-07-01

Over the past century, the southern sea otter (SSO; Enhydra lutris nereis) population has been slowly recovering from near extinction due to overharvest. The SSO is a threatened subspecies under federal law and a fully protected species under California law, US. Through a multiagency collaborative program, stranded animals are rehabilitated and released, while deceased animals are necropsied and tissues are cryopreserved to facilitate scientific study. Here, we processed archival tissues to enrich particle-associated viral nucleic acids, which we randomly amplified and deeply sequenced to identify viral genomes through sequence similarities. Anelloviruses and endogenous retroviral sequences made up over 50% of observed viral sequences. Polyomavirus, parvovirus, and adenovirus sequences made up most of the remaining reads. We characterized and phylogenetically analyzed the full genome of sea otter polyomavirus 1 and the complete coding sequence of sea otter parvovirus 1 and found that the closest known viruses infect primates and domestic pigs ( Sus scrofa domesticus), respectively. We tested archived tissues from 69 stranded SSO necropsied over 14 yr (2000-13) by PCR. Polyomavirus, parvovirus, and adenovirus infections were detected in 51, 61, and 29% of examined animals, respectively, with no significant increase in frequency over time, suggesting endemic infection. We found that 80% of tested SSO were infected with at least one of the three DNA viruses, whose tissue distribution we determined in 261 tissue samples. Parvovirus DNA was most frequently detected in mesenteric lymph node, polyomavirus DNA in spleen, and adenovirus DNA in multiple tissues (spleen, retropharyngeal and mesenteric lymph node, lung, and liver). This study describes the virome in tissues of a threatened species and shows that stranded SSO are frequently infected with multiple viruses, warranting future research to investigate associations between these infections and observed lesions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monson, D.H.; Ballachey, B.

Age distribution of sea otters (Enhydra lutris) found dead on beaches in western Prince William Sound Alaska, from 1976 to 1984, were compared to those of sea otters found dead from 1989 to 1993, following the Exxon Valdez oil spill. The age distribution of sea otters recovered in western Prince William Sound prior to the spill was bimodal and composed of primarily young and old animals. The high proportion of prime-age otters recovered immediately following the spill indicates significant losses occurred within a segment of the population which normally experiences very low mortality. The high proportion of prime-age otters recoveredmore » in 1990-1991 may be evidence of a prolonged, spill-related effect on the western Prince William Sound sea otter population.« less

2013 update on sea otter studies to assess recovery from the 1989 Exxon Valdez oil spill, Prince William Sound, Alaska

USGS Publications Warehouse

Ballachey, Brenda E.; Monson, Daniel H.; Esslinger, George G.; Kloecker, Kimberly A.; Bodkin, James L.; Bowen, Lizabeth; Miles, A. Keith

2014-01-01

On March 24, 1989, the tanker vessel Exxon Valdez ran aground in Prince William Sound, Alaska, spilling an estimated 42 million liters of Prudhoe Bay crude oil. Oil spread in a southwesterly direction and was deposited on shores and waters in western Prince William Sound (WPWS). The sea otter (Enhydra lutris) was one of more than 20 nearshore species considered to have been injured by the spill. Since 1989, the U.S. Geological Survey has led a research program to evaluate effects of the spill on sea otters and assess progress toward recovery, as defined by demographic and biochemical indicators. Here, we provide an update on the status of sea otter populations in WPWS, presenting findings through 2013. To assess recovery based on demographic indicators, we used aerial surveys to estimate abundance and annual collections of sea otter carcasses to evaluate patterns in ages-at-death. To assess recovery based on biochemical indicators, we quantified transcription rates for a suite of genes selected as potential indicators of oil exposure in sea otters based on laboratory studies of a related species, the mink (Mustela vison). In our most recent assessment of sea otter recovery, which incorporated results from a subset of studies through 2009, we concluded that recovery of sea otters in WPWS was underway. This conclusion was based on increasing abundance throughout WPWS, including increasing numbers at northern Knight Island, an area that was heavily oiled in 1989 and where the local sea otter population had previously shown protracted injury and lack of recovery. However, we did not conclude that the WPWS sea otter population had fully recovered, due to indications of continuing reduced survival and exposure to lingering oil in sea otters at Knight Island, at least through 2009. Based on data available through 2013, we now conclude that the status of sea otters—at all spatial scales within WPWS—is consistent with the designation of recovery from the spill as defined by the Exxon Valdez Oil Spill Trustee Council. The support for this conclusion is based primarily on demographic data, including (1) a return to estimated pre-spill abundance of sea otters at northern Knight Island, and (2) a return to pre-spill mortality patterns. Gene transcription rates in 2012 were similar in sea otters from oiled, moderately oiled and unoiled areas, suggesting abatement of exposure effects in 2012. However, because 2012 gene transcription rates generally were low for sea otters from all areas relative to 2008, we cannot fully interpret these observations without data from a wider panel of genes. This slight uncertainty with respect to the data from the biochemical indicator is outweighed by the strength of the data for the demographic indicators. The return to pre-spill numbers and mortality patterns suggests a gradual dissipation of lingering oil over the past two decades, to the point where continuing exposure is no longer of biological significance to the WPWS sea otter population.

Identification of a herpes-like virus in sea otters during rehabilitation after the T/V Exxon Valdez oil spill

USGS Publications Warehouse

Harris, R.K.; Moeller, R.B.; Lipscomb, T.P.; Pletcher, J.M.; Haebler, R.J.; Tuomi, P.A.; McCormick, C.R.; DeGange, Anthony R.; Mulcahy, Daniel M.; Williams, T.D.; Bayha, Keith; Kormendy, Jennifer

1990-01-01

During implantation of radiotelemetry devices in sea otters (Enhydra lutris) at the Seward Otter Rehabilitation Center, surgical team members noted ulcers in the oral cavity of each of five animals examined. Oral lesions were identified in 25 of 27 otters examined at the center. Histological evaluation of the lesions revealed focal areas of mucosal epithelial necrosis with associated intranuclear viral inclusion bodies. A herpes-like virus was subsequently identified ultrastructurally. The concern of releasing a virus of unknown origin and virulence into a naive wild otter population prompted management decisions restricting the movement of otters and jeopardizing the scheduled release of the otters on 27 July 1989. A team of veterinarians and otter capture personnel captured and examined 12 free-living adult otters off the coast of the southern Kenai Peninsula. Viral-induced oral lesions were identified in many of these animals establishing that the virus was indigenous to sea otters living in Alaskan waters; rehabilitated otters were released back into the wild.

Mortality trends in northern sea otters (Enhydra lutris kenyoni) collected from the coasts of Washington and Oregon (2002–15)

USGS Publications Warehouse

White, C. LeAnn; Lankau, Emily W.; Lynch, Deanna; Knowles, Susan N.; Schuler, Krysten L.; Dubey, Jitender P.; Shearn-Bochsler, Valerie I.; Isidoro Ayza, Marcos; Thomas, Nancy J.

2018-01-01

During 2002−15 we examined the causes of mortality in a population of northern sea otters (Enhydra lutris kenyoni). Beachcast sea otters were collected primarily from the coast of Washington. Although there are no permanent sea otter residents in Oregon, several beachcast otters were collected from the Oregon coast. Infectious diseases were the primary cause of death (56%) for otters we examined. Sarcocystosis was the leading infectious cause of death (54%) and was observed throughout the study period. Some infectious diseases, such as morbilliviral encephalitis and leptospirosis, were documented for a limited number of years and then not detected again despite continued testing for these pathogens in necropsied animals. Trauma was the second most common cause of death (14%) during the study period. The continued stable growth of the Washington population of otters suggests they are able to tolerate current mortality rates.

Sediment-associated aliphatic and aromatic hydrocarbons in coastal British Columbia, Canada: concentrations, composition, and associated risks to protected sea otters.

PubMed

Harris, Kate A; Yunker, Mark B; Dangerfield, Neil; Ross, Peter S

2011-10-01

Sediment-associated hydrocarbons can pose a risk to wildlife that rely on benthic marine food webs. We measured hydrocarbons in sediments from the habitat of protected sea otters in coastal British Columbia, Canada. Alkane concentrations were dominated by higher odd-chain n-alkanes at all sites, indicating terrestrial plant inputs. While remote sites were dominated by petrogenic polycyclic aromatic hydrocarbons (PAHs), small harbour sites within sea otter habitat and sites from an urban reference area reflected weathered petroleum and biomass and fossil fuel combustion. The partitioning of hydrocarbons between sediments and adjacent food webs provides an important exposure route for sea otters, as they consume ∼25% of their body weight per day in benthic invertebrates. Thus, exceedences of PAH sediment quality guidelines designed to protect aquatic biota at 20% of the sites in sea otter habitat suggest that sea otters are vulnerable to hydrocarbon contamination even in the absence of catastrophic oil spills. Copyright © 2011 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doroff, A.M.; DeGange, A.R.

Two experiments were conducted to evaluate efforts to recover sea otter (Enhydra lutris) carcasses following the Exxon Valdez oil spill. The first study was implemented during sea otter rescue and carcass recovery activities to assess the probability of carcass recovery. Twenty-five previously recovered sea otter carcasses were marked with flipper tags and released near northern Kodiak Island between 27 May and 3 June 1989. Five were recovered, for a recovery rate of 20%. In the second study, 30 radio-monitored floats designed to assess drift characteristics of floating sea otter carcasses were deployed in early summer 1990. During a 43-day monitoringmore » period, 27 were known to have washed ashore, 25 in Prince William Sound (PWS) and two on the Gulf of Alaska coast of Montague Island. These studies suggest that many more sea otters may have died from the spill than were recovered, and that some sea otters succumbing to oil exposure in PWS could have drifted outside of PWS and never been recovered.« less

Variations of transcript profiles between sea otters Enhydra lutris from Prince William Sound, Alaska, and clinically normal reference otters

USGS Publications Warehouse

Miles, A. Keith; Bowen, Lizabeth; Ballachey, Brenda E.; Bodkin, James L.; Murray, M.; Estes, J.L.; Keister, Robin A.; Stott, J.L.

2012-01-01

Development of blood leukocyte gene transcript profiles has the potential to expand condition assessments beyond those currently available to evaluate wildlife health, including sea otters Enhydra lutris, both individually and as populations. The 10 genes targeted in our study represent multiple physiological systems that play a role in immuno-modulation, inflammation, cell protection, tumor suppression, cellular stress-response, xenobiotic metabolizing enzymes, and antioxidant enzymes. These genes can be modified by biological, physical, or anthropogenic impacts and consequently provide information on the general type of stressors present in a given environment. We compared gene transcript profiles of sea otters sampled in 2008 among areas within Prince William Sound impacted to varying degrees by the 1989 ‘Exxon Valdez’ oil spill with those of captive and wild reference sea otters. Profiles of sea otters from Prince William Sound showed elevated transcription in genes associated with tumor formation, cell death, organic exposure, inflammation, and viral exposure when compared to the reference sea otter group, indicating possible recent and chronic exposure to organic contaminants. Sea otters from historically designated oiled areas within Prince William Sound 19 yr after the oil spill had higher transcription of genes associated with tumor formation, cell death, heat shock, and inflammation than those from areas designated as less impacted by the spill.

A Quantitative Ecological Risk Assessment of the Toxicological Risks from Exxon Valdez Subsurface Oil Residues to Sea Otters at Northern Knight Island, Prince William Sound, Alaska

PubMed Central

Harwell, Mark A.; Gentile, John H.; Johnson, Charles B.; Garshelis, David L.; Parker, Keith R.

2010-01-01

A comprehensive, quantitative risk assessment is presented of the toxicological risks from buried Exxon Valdez subsurface oil residues (SSOR) to a subpopulation of sea otters (Enhydra lutris) at Northern Knight Island (NKI) in Prince William Sound, Alaska, as it has been asserted that this subpopulation of sea otters may be experiencing adverse effects from the SSOR. The central questions in this study are: could the risk to NKI sea otters from exposure to polycyclic aromatic hydrocarbons (PAHs) in SSOR, as characterized in 2001–2003, result in individual health effects, and, if so, could that exposure cause subpopulation-level effects? We follow the U.S. Environmental Protection Agency (USEPA) risk paradigm by: (a) identifying potential routes of exposure to PAHs from SSOR; (b) developing a quantitative simulation model of exposures using the best available scientific information; (c) developing scenarios based on calculated probabilities of sea otter exposures to SSOR; (d) simulating exposures for 500,000 modeled sea otters and extracting the 99.9% quantile most highly exposed individuals; and (e) comparing projected exposures to chronic toxicity reference values. Results indicate that, even under conservative assumptions in the model, maximum-exposed sea otters would not receive a dose of PAHs sufficient to cause any health effects; consequently, no plausible toxicological risk exists from SSOR to the sea otter subpopulation at NKI. PMID:20862194

The distribution of 4-nonylphenol in marine organisms of North American Pacific Coast estuaries.

PubMed

Diehl, Jennifer; Johnson, Sarah E; Xia, Kang; West, Amy; Tomanek, Lars

2012-04-01

One of the chemical breakdown products of nonylphenol ethoxylates, 4-nonylphenol (4-NP), accumulates in organisms and is of concern as an environmental pollutant due to its endocrine disrupting effects. We measured 4-NP levels in the seawater, sediment, and twelve organisms within the California estuary, Morro Bay, and examined biomagnification of 4-NP using stable isotope abundances (δ(15)N and δ(13)C) to quantify trophic position. 4-NP concentrations in organisms from Morro Bay included 25000±8600 ng g(-1) lw in liver of California sea lion, 14000±5600 ng g(-1) lw in liver of harbor porpoise, 138000±55000 ng g(-1) lw in liver of sea otters, 15700±3600 ng g(-1) lw in liver of seabirds, 36100±6100 ng g(-1) lw in arrow goby fish, 62800±28400 ng g(-1) lw in oysters, and 12700±1300 ng g(-1) lw in mussels. 4-NP levels generally showed a pattern of trophic dilution among organisms in Morro Bay, with exceptions of biomagnification observed between three trophic links: mussel to sea otter (BMF 10.9), oyster to sea otter (BMF 2.2), and arrow goby to staghorn sculpin (BMF 2.7). Our examination of other west coast estuaries of USA and Canada revealed that mean 4-NP concentrations in gobies and mussels from Morro Bay were significantly higher than those from a more urbanized estuary, San Francisco Bay (goby: 11100±3800 ng g(-1) lw) and from a remote estuary, Bamfield Inlet, Canada (goby: 9000±900 ng g(-1) lw, mussel: 6100±700 ng g(-1) lw). Relative to other estuaries worldwide, 4-NP levels in seawater (0.42±0.16 μg L(-1)) and sediment (53±14 ng g(-1) dw) of Morro Bay are low, but gobies and oysters have higher 4-NP levels than comparable fauna. Copyright © 2012 Elsevier Ltd. All rights reserved.

Sea otter studies in Glacier Bay National Park and Preserve: annual report 2002

USGS Publications Warehouse

Bodkin, James L.; Kloecker, Kimberly A.; Esslinger, George G.; Monson, Daniel H.; Coletti, Heather A.; Doherty, Janet

2003-01-01

Since 1995, the number of sea otters in Glacier Bay proper has increased from around 5 to more than 1200. Sea otter distribution is mostly limited to the Lower Bay, south of Sandy Cove, and is not continuous within that area. Concentrations occur in the vicinity of Sita Reef and Boulder Island and between Pt. Carolus and Rush Pt. on the west side of the Bay, although there have been occasional sightings north of Sandy Cove (Figure 1). Large portions of the Bay remain unoccupied by sea otters, but recolonization is occurring rapidly. Most prey recovered by sea otters in Glacier Bay are ecologically, commercially, or socially important species. In 2002 sea otter diet consisted of 35% clam, 26% mussel, 3% crab, 3.0% snail, 2% starfish, 11% urchins, 2% other, and 20% unidentified. Dominant clam species include the butter clam, Saxidomus gigantea, the Greenland cockle, Serripes groenlandicus, and the littleneck clam, Protothaca staminea. Urchins are primarily green urchins, Strongylocentrotus droebachiensis, and the mussel is Modiolus modiolus. Crabs observed in 2002 include the Dungeness, Cancer magister, the kelp crab Pugettia gracilis, and the helmet crab, Telmessus cherigonus. Although we characterize diet at broad geographic scales, we have previously found diet to vary between sites separated by as little as several hundred meters. Dietary variation among and within sites can reflect differences in prey availability as well as individual specialization. We estimated species composition, density, biomass, and sizes of subtidal clams, urchins, and mussels at 13 sites in Glacier Bay and 5 sites in nearby Port Althorp, where sea otters have been present for at least 20 years. All sites were selected based on the presence of abundant clam siphons and the absence of sea otters (Glacier Bay) or abundant shell litter and the presence of sea otters (Port Althorp). Glacier Bay sites were selected to achieve a broad geographic sample of dense subtidal clam beds within Glacier Bay prior to occupation and foraging by sea otters. Port Althorp sites were chosen to achieve a representative sample of subtidal clam beds already under prolonged foraging pressure by sea otters. There was no direct evidence of otter foraging at any of our Glacier Bay sampling sites. In Glacier Bay, we sampled 15,338 bivalves (average of 1,180/site) representing 14 species of clam, 2 species of mussel, and a single scallop and we sampled 6,917 urchins (average of 513/site). In Port Althorp, we sampled 1,034 bivalves (average of 207/site) representing 14 species of clam. We found only 5 urchins, all S. droebachiensis. Mean densities and biomass of all subtidal clams were significantly greater in Glacier Bay (59.2 and 99/0.25m2 compared to Port Althorp (10.3 and 5.8/0.25m2 (p Our contrasts of subtidal clam populations between Glacier Bay and Port Althorp suggest that clam densities will likely decline by about a factor of six and that clam biomass estimates will decline by more than a factor of ten. Numerically dominant species of clams, P. staminea, S. gigantea, Macoma sp. and Mya sp. were all significantly greater in density and biomass in Glacier Bay, while C. nutalli density was low but significantly higher in Port Althorp. Subtidal clam species diversity was significantly greater in Port Althorp compared to Glacier Bay, although this may simply reflect habitat differences. Sea urchin densities were high in Glacier Bay, while in Port Althorp urchins were virtually absent. Sea otters are now well established in limited areas of the lower portions of Glacier Bay. It is likely that distribution and numbers of sea otters will continue to increase in Glacier Bay in the near future. Glacier Bay supports large and diverse populations of clams that are largely unexploited by sea otters at present. It is predictable that the density and sizes of clam populations will decline in response to otter predation. This will result in fewer opportunities for human harvest, but will also trigger ecosystem level changes, as prey for other predators, such as octopus, sea stars, fishes, birds and mammals are modified. Sea otters will also modify benthic habitats through excavation of sediments required to extract burrowing infauna such as clams. Effects of sediment disturbance by foraging sea otters are not understood. Glacier Bay also supports large populations of other preferred sea otter prey, such as king (Paralithodes sp.), tanner (Chionoecetes sp.) and dungeness (Cancer magister) crabs and green sea urchins (S. droebachiensis). As the colonization of Park waters by sea otters continues, it is also likely that dramatic changes will occur in the species composition, abundance, and size class distribution of many components of the nearshore marine ecosystem. Many of the changes will occur as a direct result of predation by sea otters. Others will result from indirect or cascading effects of sea otter foraging, such as increased kelp production and modified prey availability for other nearshore predators. Without recognizing and quantifying the extent of change initiated by the colonization of Glacier Bay by sea otters, management of nearshore resources will be severely constrained for many decades.

Sarcocystis neurona retinochoroiditis in a sea otter (Enhydra lutris kenyoni)

USDA-ARS?s Scientific Manuscript database

Sarcocystis neurona is an important cause of fatal disease in sea otters in the USA. Encephalitis is the predominant lesion and parasites are confined to the central nervous system and muscles. Here we report retinochoroiditis in a sea otter (Enhydra lutris kenyoni) found dead on Copalis Beach, WA, ...

Assessing Risks to Sea Otters and the Exxon Valdez Oil Spill: New Scenarios, Attributable Risk, and Recovery

PubMed Central

Harwell, Mark A.; Gentile, John H.

2014-01-01

The Exxon Valdez oil spill occurred more than two decades ago, and the Prince William Sound ecosystem has essentially recovered. Nevertheless, discussion continues on whether or not localized effects persist on sea otters (Enhydra lutris) at northern Knight Island (NKI) and, if so, what are the associated attributable risks. A recent study estimated new rates of sea otter encounters with subsurface oil residues (SSOR) from the oil spill. We previously demonstrated that a potential pathway existed for exposures to polycyclic aromatic hydrocarbons (PAHs) and conducted a quantitative ecological risk assessment using an individual-based model that simulated this and other plausible exposure pathways. Here we quantitatively update the potential for this exposure pathway to constitute an ongoing risk to sea otters using the new estimates of SSOR encounters. Our conservative model predicted that the assimilated doses of PAHs to the 1-in-1000th most-exposed sea otters would remain 1–2 orders of magnitude below the chronic effects thresholds. We re-examine the baseline estimates, post-spill surveys, recovery status, and attributable risks for this subpopulation. We conclude that the new estimated frequencies of encountering SSOR do not constitute a plausible risk for sea otters at NKI and these sea otters have fully recovered from the oil spill. PMID:24587690

Bald eagles and sea otters in the Aleutian Archipelago: indirect effects of trophic cascades.

USGS Publications Warehouse

Anthony, R.G.; Estes, J.A.; Ricca, M.A.; Miles, A.K.; Forsman, E.D.

2008-01-01

Because sea otters (Enhydra lutris) exert a wide array of direct and indirect effects on coastal marine ecosystems throughout their geographic range, we investigated the potential influence of sea otters on the ecology of Bald Eagles (Haliaeetus leucocephalus) in the Aleutian Islands, Alaska, USA. We studied the diets, productivity, and density of breeding Bald Eagles on four islands during 1993–1994 and 2000–2002, when sea otters were abundant and scarce, respectively. Bald Eagles depend on nearshore marine communities for most of their prey in this ecosystem, so we predicted that the recent decline in otter populations would have an indirect negative effect on diets and demography of Bald Eagles. Contrary to our predictions, we found no effects on density of breeding pairs on four islands from 1993–1994 to 2000–2002. In contrast, diets and diet diversity of Bald Eagles changed considerably between the two time periods, likely reflecting a change in prey availability resulting from the increase and subsequent decline in sea otter populations. The frequency of sea otter pups, rock greenling (Hexagammus lagocephalus), and smooth lumpsuckers (Aptocyclus ventricosus) in the eagle's diet declined with corresponding increases in Rock Ptarmigan (Lagopus mutus), Glaucous-winged Gulls (Larus glaucescens), Atka mackerel (Pleurogrammus monopterygius), and various species of seabirds during the period of the recent otter population decline. Breeding success and productivity of Bald Eagles also increased during this time period, which may be due to the higher nutritional quality of avian prey consumed in later years. Our results provide further evidence of the wide-ranging indirect effects of sea otter predation on nearshore marine communities and another apex predator, the Bald Eagle. Although the indirect effects of sea otters are widely known, this example is unique because the food-web pathway transcended five species and several trophic levels in linking one apex predator to another.

ANTIDOG IgG SECONDARY ANTIBODY SUCCESSFULLY DETECTS IgG IN A VARIETY OF AQUATIC MAMMALS.

PubMed

Roehl, Katherine; Jankowski, Mark; Hofmeister, Erik

2016-12-01

Serological tests play an important role in the detection of wildlife diseases. However, while there are many commercial assays and reagents available for domestic species, there is a need to develop efficient serological assays for wildlife. In recent years, marine mammals have represented a wildlife group with emerging infectious diseases, such as influenza, brucellosis, and leptospirosis. However, with the exception of disease-agent-specific assays or functional assays, few reports describe the use of antibody detection assays in marine mammals. In an indirect enzyme-linked immunoassay (EIA) or an immunofluorescence assay, antibody is detected using an antitarget species secondary conjugated antibody. The sensitivity of the assay depends on the avidity of the binding reaction between the bound antibody and the detection antibody. A commercial polyclonal antidog IgG conjugated antibody was tested in an EIA for its ability to sensitively detect the IgG of seven marine mammals including sea otter ( Enhydra lutris ), polar bear ( Ursus maritimus ), grey seal ( Halichoerus grypus ), harbor seal ( Phoca vitulina ), northern elephant seal ( Mirounga angustirostris ), California sea lion ( Zalophus californianus ), Pacific walrus ( Odobenus rosmarus ) and one freshwater mammal: Asian small-clawed otter ( Aonyx cinerea ). With the exception of Asian small-clawed sea otters, the detection of IgG in these marine mammals either exceeded or was nearly equal to detection of dog IgG. The use of the tested commercial antidog IgG antibody may be a valid approach to the detection of antibody response to disease in sea mammals.

Anti-dog IgG secondary antibody successfully detects IgG in a variety of aquatic mammals

USGS Publications Warehouse

Roehl, Katherine; Jankowski, Mark D.; Hofmeister, Erik K.

2016-01-01

Serological tests play an important role in the detection of wildlife diseases. However, while there are many commercial assays and reagents available for domestic species, there is a need to develop efficient serological assays for wildlife. In recent years, marine mammals have represented a wildlife group with emerging infectious diseases, such as influenza, brucellosis, and leptospirosis. However, with the exception of disease-agent-specific assays or functional assays, few reports describe the use of antibody detection assays in marine mammals. In an indirect enzyme-linked immunoassay (EIA) or an immunofluorescence assay, antibody is detected using an antitarget species secondary conjugated antibody. The sensitivity of the assay depends on the avidity of the binding reaction between the bound antibody and the detection antibody. A commercial polyclonal antidog IgG conjugated antibody was tested in an EIA for its ability to sensitively detect the IgG of seven marine mammals including sea otter (Enhydra lutris), polar bear (Ursus maritimus), grey seal (Halichoerus grypus), harbor seal (Phoca vitulina), northern elephant seal (Mirounga angustirostris), California sea lion (Zalophus californianus), Pacific walrus (Odobenus rosmarus) and one freshwater mammal: Asian small-clawed otter (Aonyx cinerea). With the exception of Asian small-clawed sea otters, the detection of IgG in these marine mammals either exceeded or was nearly equal to detection of dog IgG. The use of the tested commercial antidog IgG antibody may be a valid approach to the detection of antibody response to disease in sea mammals.

Refining aging criteria for northern sea otters in Washington State

USGS Publications Warehouse

Schuler, Krysten L.; Baker, Bridget B.; Mayer, Karl A.; Perez-Heydrich, Carolina; Holahan, Paula M.; Thomas, Nancy J.; White, C. LeAnn

2018-01-01

Measurement of skull ossification patterns is a standard method for aging various mammalian species and has been used to age Russian, Californian, and Alaskan sea otter populations. Cementum annuli counts have also been verified as an accurate aging method for the Alaskan sea otter population. In this study, cementum annuli count results and skull ossification patterns were compared as methods for aging the northern sea otter (Enhydra lutris kenyoni) population in Washington State. Significant agreement was found between the two methods suggesting that either method could be used to age the Washington population of otters. This study also found that ossification of the squamosal-jugal suture at the ventral glenoid fossa can be used to differentiate male subadults from adults. To assist field biologists or others without access to cementum annuli or skull ossification analysis techniques, a suite of morphologic, physiologic, and developmental characteristics were analyzed to assess whether a set of these more easily accessible parameters could also predict age class for the Washington population of otters. Tooth condition score, evidence of reproductive activity in females, and tooth eruption pattern were identified as the most useful criteria for classifying Washington sea otters as pups, juveniles, subadults, or adults/aged adults. A simple decision tree based on characteristics accessible in the field or at necropsy was created that can be used to reliably predict age class of Washington sea otters as determined by cementum annuli.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballachey, B.E.; Kloecker, K.A.

Ten moderately to heavily oiled sea otters were collected in Prince William Sound during the Exxon Valdez oil spill and up to seven tissues from each were analyzed for hydrocarbons. Aliphatic and aromatic hydrocarbons were detected in all tissues. Concentrations of aromatic hydrocarbons in fat samples were an order of magnitude higher than in other tissues. The patterns of distribution of these hydrocarbons suggested crude oil as the source of contamination. However, there was variation among oiled otters in the concentrations of individual hydrocarbons, which may be due to differing proximate causes of mortality and varying lengths of time andmore » sea otters survived following oil exposure. The concentrations of both aliphatic and aromatic hydrocarbons in the tissues of the ten oiled sea otters generally were higher than in tissues from 7 sea otters with no external oiling that were collected from prince William Sound in 1989 and 1990, or from 12 sea otters collected from an area in southeast Alaska which had not experienced an oil spill.« less

Gene transcription in sea otters (Enhydra lutris); development of a diagnostic tool for sea otter and ecosystem health

USGS Publications Warehouse

Bowen, Lizabeth; Miles, A. Keith; Murray, Michael; Haulena, Martin; Tuttle, Judy; van Bonn, William; Adams, Lance; Bodkin, James L.; Ballachey, Brenda E.; Estes, James A.; Tinker, M. Tim; Keister, Robin; Stott, Jeffrey L.

2012-01-01

Gene transcription analysis for diagnosing or monitoring wildlife health requires the ability to distinguish pathophysiological change from natural variation. Herein, we describe methodology for the development of quantitative real-time polymerase chain reaction (qPCR) assays to measure differential transcript levels of multiple immune function genes in the sea otter (Enhydra lutris); sea otter-specific qPCR primer sequences for the genes of interest are defined. We establish a ‘reference’ range of transcripts for each gene in a group of clinically healthy captive and free-ranging sea otters. The 10 genes of interest represent multiple physiological systems that play a role in immuno-modulation, inflammation, cell protection, tumour suppression, cellular stress response, xenobiotic metabolizing enzymes, antioxidant enzymes and cell–cell adhesion. The cycle threshold (CT) measures for most genes were normally distributed; the complement cytolysis inhibitor was the exception. The relative enumeration of multiple gene transcripts in simple peripheral blood samples expands the diagnostic capability currently available to assess the health of sea otters in situ and provides a better understanding of the state of their environment.

Sea otter population declines in the Aleutian Archipelago

USGS Publications Warehouse

Doroff, Angela M.; Estes, James A.; Tinker, M. Tim; Burn, Douglas M.; Evans, Thomas J.

2003-01-01

Sea otter (Enhydra lutris) populations were exploited to near extinction and began to recover after the cessation of commercial hunting in 1911. Remnant colonies of sea otters in the Aleutian archipelago were among the first to recover; they continued to increase through the 1980s but declined abruptly during the 1990s. We conducted an aerial survey of the Aleutian archipelago in 2000 and compared results with similar surveys conducted in 1965 and 1992. The number of sea otters counted decreased by 75% between 1965 and 2000; 88% for islands at equilibrial density in 1965. The population decline likely began in the mid-1980s and declined at a rate of 17.5%/year in the 1990s. The minimal population estimate was 8,742 sea otters in 2000. The population declined to a uniformly low density in the archipelago, suggesting a common and geographically widespread cause. These data are in general agreement with the hypothesis of increased predation on sea otters. These data chronicle one of the most widespread and precipitous population declines for a mammalian carnivore in recorded history.

78 FR 34652 - Proposed Information Collection; Comment Request; Reporting Requirements for Sea Otter...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-10

.... If a southern sea otter is entangled in a net, regardless of whether the animal is injured or killed... of interaction; otter's behavior during interaction; and, measures taken to avoid interaction. II...

First Report of an Adult Tapeworm (Cestoda: Diphyllobothriidea) in a Southern Sea Otter (Enhydra lutris nereis).

PubMed

Young, Colleen; Miller, Melissa A; Kuchta, Roman; Brabec, Jan; Newsome, Seth D; Dailey, Murray

2017-10-01

We present a novel case of an intestinal cestode infection in a southern sea otter (Enhydra lutris nereis). The cestode species Diphyllobothrium tetrapterum (syn. Diplogonoporus tetrapterus) was confirmed genetically. Stable isotope analysis of whiskers collected from the sea otter did not confirm the consumption of fish as the route of exposure.

Hearing in the sea otter (Enhydra lutris): auditory profiles for an amphibious marine carnivore.

PubMed

Ghoul, Asila; Reichmuth, Colleen

2014-11-01

In this study we examine the auditory capabilities of the sea otter (Enhydra lutris), an amphibious marine mammal that remains virtually unstudied with respect to its sensory biology. We trained an adult male sea otter to perform a psychophysical task in an acoustic chamber and at an underwater apparatus. Aerial and underwater audiograms were constructed from detection thresholds for narrowband signals measured in quiet conditions at frequencies from 0.125-40 kHz. Aerial hearing thresholds were also measured in the presence of octave-band masking noise centered at eight signal frequencies (0.25-22.6 kHz) so that critical ratios could be determined. The aerial audiogram of the sea otter resembled that of sea lions and showed a reduction in low-frequency sensitivity relative to terrestrial mustelids. Best sensitivity was -1 dB re 20 µPa at 8 kHz. Under water, hearing sensitivity was significantly reduced when compared to sea lions and other pinniped species, demonstrating that sea otter hearing is primarily adapted to receive airborne sounds. Critical ratios were more than 10 dB higher than those measured for pinnipeds, suggesting that sea otters are less efficient than other marine carnivores at extracting acoustic signals from background noise, especially at frequencies below 2 kHz.

Trial aerial survey of sea otters in Prince William Sound, Alaska, 1993. Restoration project 93043-2. Exxon Valdez oil spill restoration project final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bodkin, J.L.; Udevitz, M.S.

1996-05-01

We developed an aerial survey method for sea otters, using a strip transect design where otters observed in a strip along one side of the aircraft are counted. Two strata are sampled, one lies close to shore and/or in shallow. The other strata lies offshore and over deeper water. We estimate the proportion of otters not seen by the observer by conducting intensive searches of units (ISU`s) within strips when otters are observed. The first study found no significant differences in sea otter detection probabilities between ISU`s initiated by the sighting of an otter group compared to systematically located ISU`s.more » The second study consisted of a trial survey of all of Prince William Sound, excluding Orca Inlet. The survey area consisted of 5,017 sq km of water between the shore line and an offshore boundary based on shoreline physiography, the 100 m depth contour or a distance of 2 km from the shore. From 5-13 August 1993, two observers surveyed 1,023 linear km of high density sea otter habitat and 355 linear km of low density habitat.« less

Sea otter population status and the process of recovery from the 1989 'Exxon Valdez' oil spill

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.; Dean, T.A.; Fukuyama, Allan K.; Jewett, S.C.; McDonald, L.; Monson, Daniel H.; O'Clair, Charles E.; VanBlaricom, G.R.

2002-01-01

Sea otter Enhydra lutris populations were severely affected by the 1989 'Exxon Valdez' oil spill in western Prince William Sound, AK, and had not fully recovered by 2000. Here we present results of population surveys and incorporate findings from related studies to identify current population status and factors affecting recovery. Between 1993 and 2000, the number of sea otters in the spill-area of Prince William Sound increased by about 600 to nearly 2700. However, at Knight Island, where oil exposure and sea otter mortality in 1989 was most severe, no increase has been observed. Sea otter reproduction was not impaired, and the age and sex composition of captured otters are consistent with both intrinsic reproduction and immigration contributing to recovery. However, low resighting rates of marked otters at Knight Island compared to an unoiled reference area, and high proportions of young otters in beach cast carcasses through 1998, suggest that the lack of recovery was caused by relatively poor survival or emigration of potential recruits. Significantly higher levels of cytochrome P4501A (CYP1A), a biomarker of hydrocarbons, were found in sea otters at Knight Island from 1996 to 1998 compared to unoiled Montague Island, implicating oil effects in the lack of recovery at Knight Island. Delayed recovery does not appear to be directly related to food limitation. Although food availability was relatively low at both oiled and unoiled areas, we detected significant increases in sea otter abundance only at Montague Island, a finding inconsistent with food as a principal limiting factor. Persistent oil in habitats and prey provides a source of continued oil exposure and, combined with relatively low prey densities, suggests a potential interaction between oil and food. However, sea otters foraged more successfully at Knight Island and young females were in better condition than those at Montague Island. We conclude that progress toward recovery of sea otters in Prince William Sound is evident, but that in areas where initial oil effects were greatest, recovery may be constrained by residual spill effects, resulting from elevated mortality and emigration. It is evident that internal reproduction and immigration of juveniles has been the primary means of population recovery, as opposed to broad scale redistribution of adults from outside affected areas. The result is a recovery period protracted by long-term spill effects on survival and emigration and intrinsic limits to population growth.

Long-term effects of the 'Exxon Valdez' oil spill: Sea otter foraging in the intertidal as a pathway of exposure to lingering oil

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.; Coletti, Heather A.; Esslinger, George G.; Kloecker, Kimberly A.; Rice, Stanley D.; Reed, John; Monson, Daniel H.

2012-01-01

The protracted recovery of some bird and mammal populations in western Prince William Sound (WPWS), Alaska, and the persistence of spilled 'Exxon Valdez' oil in intertidal sediments, suggests a pathway of exposure to consumers that occupy nearshore habitats. To evaluate the hypothesis that sea otter (Enhydra lutris) foraging allows access to lingering oil, we contrast spatial relations between foraging behavior and documented oil distribution. We recovered archival time-depth recorders implanted in 19 sea otters in WPWS, where lingering oil and delayed ecosystem recovery are well documented. Sea otter foraging dives ranged from +2.7 to -92 m below sea level (MLLW), with intertidal accounting for 5 to 38% of all foraging. On average, female sea otters made 16050 intertidal dives per year and 18% of these dives were at depths above the +0.80 m tidal elevation. Males made 4100 intertidal dives per year and 26% of intertidal foraging took place at depths above the +0.80 m tidal elevation. Estimated annual oil encounter rates ranged from 2 to 24 times yr-1 for females, and 2 to 4 times yr-1 for males. Exposure rates increased in spring when intertidal foraging doubled and females were with small pups. In summer 2008, we found sea otter foraging pits on 13.5 of 24.8 km of intertidal shoreline surveyed. Most pits (82%) were within 0.5 m of the zero tidal elevation and 15% were above 0.5 m, the level above which most (65%) lingering oil remains. In August 2008, we detected oil above background concentrations in 18 of 41 (44%) pits excavated by sea otters on beaches with prior evidence of oiling, with total PAH concentrations up to 56000 ng g−1 dry weight. Our estimates of intertidal foraging, the widespread presence of foraging pits in the intertidal, and the presence of oil in and near sea otter foraging pits documents a pathway of exposure from lingering intertidal oil to sea otters foraging in WPWS.

Auditory Sensitivity and Masking Profiles for the Sea Otter (Enhydra lutris).

PubMed

Ghoul, Asila; Reichmuth, Colleen

2016-01-01

Sea otters are threatened marine mammals that may be negatively impacted by human-generated coastal noise, yet information about sound reception in this species is surprisingly scarce. We investigated amphibious hearing in sea otters by obtaining the first measurements of absolute sensitivity and critical masking ratios. Auditory thresholds were measured in air and underwater from 0.125 to 40 kHz. Critical ratios derived from aerial masked thresholds from 0.25 to 22.6 kHz were also obtained. These data indicate that although sea otters can detect underwater sounds, their hearing appears to be primarily air adapted and not specialized for detecting signals in background noise.

Correlates to survival of juvenile sea otters in Prince William Sound, Alaska, 1992-1993

USGS Publications Warehouse

Ballachey, Brenda E.; Bodkin, James L.; Howlin, S.; Doroff, A.M.; Rebar, A.H.

2003-01-01

We estimated survival of sea otters (Enhydra lutris) for 1 year post weaning during 1992-1993 in Prince William Sound (PWS), location of the 1989 Exxon Valdez oil spill. We sampled 38 pups in eastern PWS (EPWS), an unoiled area occupied by sea otters for 25 years. We compared survival between areas, sexes, and condition groups. We also examined the relation of blood parameters to survival. Survival was estimated at 0.74 in EPWS and 0.52 in WPWS. Female survival was 0.86 in EPWS and 0.64 in WPWS, whereas male survival was lower, 0.61 in EPWS and 0.44 in WPWS. Sea otters from EPWS were in better condition (mass/length) than WPWS sea otters. Pups in better condition had higher survival in EPWS but not in WPWS. Foraging success was greater in EPWS than in WPWS, consistent with either an effect of length of occupation or the effects of oil on the prey base or a combination of these effects. Area differences in blood parameters suggested liver damage in WPWS sea otters, perhaps resulting from continued exposure to oil. Thus, both length of occupation and oiling history likely influenced juvenile survival in PWS.

Modest genetic differentiation among North American populations of Sarcocystis neurona may reflect expansion in its geographic range.

PubMed

Sundar, N; Asmundsson, I M; Thomas, N J; Samuel, M D; Dubey, J P; Rosenthal, B M

2008-03-25

Sarcocystis neurona is an important cause of neurological disease in horses (equine protozoal myeloencephalitis, EPM) and sea otters in the United States. In addition, EPM-like disease has been diagnosed in several other land and marine mammals. Opossums are its only definitive hosts. Little genetic diversity among isolates of S. neurona from different hosts has been reported. Here, we used 11 microsatellites to characterize S. neurona DNA isolated from natural infections in 22 sea otters (Enhydra lutris) from California and Washington and in 11 raccoons (Procyon lotor) and 1 striped skunk (Mephitis mephitis) from Wisconsin. By jointly analyzing these 34 isolates with 26 isolates previously reported, we determined that geographic barriers may limit S. neurona dispersal and that only a limited subset of possible parasite genotypes may have been introduced to recently established opossum populations. Moreover, our study confirms that diverse intermediate hosts share a common infection source, the opossum (Didelphis virginiana).

Modest genetic differentiation among North American populations of Sarcocystic neurona may reflect expansion in its geographic range

USGS Publications Warehouse

Sundar, N.; Asmundsson, I.M.; Thomas, N.J.; Samuel, M.D.; Dubey, J.P.; Rosenthal, B.M.

2008-01-01

Sarcocystis neurona is an important cause of neurological disease in horses (equine protozoal myeloencephalitis, EPM) and sea otters in the United States. In addition, EPM-like disease has been diagnosed in several other land and marine mammals. Opossums are its only definitive hosts. Little genetic diversity among isolates of S. neurona from different hosts has been reported. Here, we used 11 microsatellites to characterize S. neurona DNA isolated from natural infections in 22 sea otters (Enhydra lutris) from California and Washington and in 11 raccoons (Procyon lotor) and 1 striped skunk (Mephitis mephitis) from Wisconsin. By jointly analyzing these 34 isolates with 26 isolates previously reported, we determined that geographic barriers may limit S. neurona dispersal and that only a limited subset of possible parasite genotypes may have been introduced to recently established opossum populations. Moreover, our study confirms that diverse intermediate hosts share a common infection source, the opossum (Didelphis virginiana).

75 FR 11115 - Proposed Information Collection; Comment Request; Reporting Requirements for Sea Otter...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-10

... Collection; Comment Request; Reporting Requirements for Sea Otter Interactions with the Pacific Sardine... conservation measures under the CPS FMP. This included the requirement to report any interactions that may... interactions (defined as otters within encircled nets or coming into contact with nets or vessels, including...

Indirect food web interactions: Sea otters and kelp forest fishes in the Aleutian archipelago

USGS Publications Warehouse

Reisewitz, S.E.; Estes, J.A.; Simenstad, C.A.

2006-01-01

Although trophic cascades - the effect of apex predators on progressively lower trophic level species through top-down forcing - have been demonstrated in diverse ecosystems, the broader potential influences of trophic cascades on other species and ecosystem processes are not well studied. We used the overexploitation, recovery and subsequent collapse of sea otter (Enhydra lutris) populations in the Aleutian archipelago to explore if and how the abundance and diet of kelp forest fishes are influenced by a trophic cascade linking sea otters with sea urchins and fleshy macroalgae. We measured the abundance of sea urchins (biomass density), kelp (numerical density) and fish (Catch per unit effort) at four islands in the mid-1980s (when otters were abundant at two of the islands and rare at the two others) and in 2000 (after otters had become rare at all four islands). Our fish studies focused on rock greenling (Hexagrammos lagocephalus), the numerically dominant species in this region. In the mid-1980s, the two islands with high-density otter populations supported dense kelp forests, relatively few urchins, and abundant rock greenling whereas the opposite pattern (abundant urchins, sparse kelp forests, and relatively few rock greenling) occurred at islands where otters were rare. In the 2000, the abundances of urchins, kelp and greenling were grossly unchanged at islands where otters were initially rare but had shifted to the characteristic pattern of otter-free systems at islands where otters were initially abundant. Significant changes in greenling diet occurred between the mid-1980s and the 2000 although the reasons for these changes were difficult to assess because of strong island-specific effects. Whereas urchin-dominated communities supported more diverse fish assemblages than kelp-dominated communities, this was not a simple effect of the otter-induced trophic cascade because all islands supported more diverse fish assemblages in 2000 than in the mid-1980s. ?? Springer-Verlag 2005.

Serologic evidence of influenza A(H1N1)pdm09 virus in northern sea otters

USGS Publications Warehouse

Li, Zhu-Nan; Ip, Hon S.; Frost, Jessica F.; White, C. LeAnn; Murray, Michael J.; Carney, Paul J.; Sun, Xiang-Jie; Stevens, James; Levine, Min Z.; Katz, Jacqueline M.

2014-01-01

Sporadic epizootics of pneumonia among marine mammals have been associated with multiple animal-origin influenza A virus subtypes (1–6); seals are the only known nonhuman host for influenza B viruses (7). Recently, we reported serologic evidence of influenza A virus infection in free-ranging northern sea otters (Enhydra lutris kenyoni) captured off the coast of Washington, USA, in August 2011 (8). To investigate further which influenza A virus subtype infected these otters, we tested serum samples from these otters by ELISA for antibody-binding activity against 12 recombinant hemagglutinins (rHAs) from 7 influenza A hemagglutinin (HA) subtypes and 2 lineages of influenza B virus (Technical Appendix Table 1). Estimated ages for the otters were 2–19 years (Technical Appendix Table 2); we also tested archived serum samples from sea otters of similar ages collected from a study conducted during 2001–2002 along the Washington coast (9).

Genotypic Characterization of Streptococcus infantarius subsp. coli Isolates from Sea Otters with Infective Endocarditis and/or Septicemia and from Environmental Mussel Samples

PubMed Central

Counihan-Edgar, Katrina L.; Gill, Verena A.; Doroff, Angela M.; Burek, Kathleen A.; Miller, Woutrina A.; Shewmaker, Patricia L.; Jang, Spencer; Goertz, Caroline E. C.; Tuomi, Pamela A.; Miller, Melissa A.; Jessup, David A.

2012-01-01

Pulsed-field gel electrophoresis (PFGE) was used to type 128 Streptococcus infantarius subsp. coli isolates from sea otters and mussels. Six SmaI PFGE groups were detected, with one predominant group representing 57% of the isolates collected over a wide geographic region. Several sea otter and mussel isolates were highly related, suggesting that an environmental infection source is possible. PMID:23052307

Gene sequences for cytochromes p450 1A1 and 1A2: the need for biomarker development in sea otters (Enhydra lutris).

PubMed

Hook, Sharon E; Cobb, Michael E; Oris, James T; Anderson, Jack W

2008-11-01

There has been recent public concern regarding the impacts of environmental pollution on populations of otters. Population level impacts have been seen with otter (Lutra lutra) populations in Europe due to polychlorinated biphenyls, and with some segments of the Prince William Sound, AK, sea otter (Enhydra lutris) population following the Exxon Valdez oil spill. Despite public interest in these animals and their ecological significance, there are few tools that allow for the study of otter's response to contaminant exposure. Cytochrome p450 1A (CYP1A) performs the first step in metabolizing many xenobiotics, including many polychlorinated biphenyls and polycyclic aromatic hydrocarbons. CYP1A induction is a frequently used biomarker of exposure to these compounds. Despite the potential importance of this gene in ecological risk assessment, the complete coding sequence has not been published for any otter species. This study's objective was to isolate the gene for CYP1A1 and CYP1A2 in sea otters using a series of PCR-based approaches. The coding sequences from CYP1A1 and CYP1A2 from sea otters were identified and published in GenBank. Both CYP1A sequences are homologous to those obtained from marine mammals and other carnivores. These sequences will be useful as tools for researchers assessing contaminant exposure in mustelid populations.

Could residual oil from the Exxon Valdez spill create a long-term population "sink" for sea otters in Alaska?

USGS Publications Warehouse

Monson, Daniel H.; Doak, Daniel F.; Ballachey, Brenda E.; Bodkin, James L.

2011-01-01

Over 20 years ago, the Exxon Valdez oil tanker spilled 42 million L of crude oil into the waters of Prince William Sound, Alaska, USA. At the time of the spill, the sea otter (Enhydra lutris) population inhabiting the spill area suffered substantial acute injuries and loss. Subsequent research has resulted in one of the best-studied species responses to an oil spill in history. However, the question remains: Is the spill still influencing the Prince William Sound sea otter population? Here we fit time-varying population models to data for the sea otter population of western Prince William Sound to quantify the duration and extent of mortality effects from the spill. We hypothesize that the patchy nature of residual oil left in the environment has created a source-sink population dynamic. We fit models using the age distributions of both living and dying animals and estimates of sea otter population size to predict the number of sea otters in the hypothesized sink population and the number lost to this sink due to chronic exposure to residual oil. Our results suggest that the sink population has remained at just over 900 individuals (95% CI: 606-960) between 1990 and 2009, during which time prime-age survival remained 2-6% below pre-spill levels. This reduced survival led to chronic losses of ???900 animals over the past two decades, which is similar in magnitude to the number of sea otter deaths documented in western Prince William Sound during the acute phase of the spill. However, the unaffected source population appears to be counterbalancing these losses, with the model indicating that the sea otter population increased from ???2150 individuals in 1990 to nearly 3000 in 2009. The most optimistic interpretation of our results suggests that mortality effects dissipated between 2005 and 2007. Our results suggest that residual oil can affect wildlife populations on time scales much longer than previously believed and that cumulative chronic effects can be as significant as acute effects. Further, source-sink population dynamics can explain the slow recovery observed in the spill-affected western Prince William Sound sea otter population and are consistent with available data. ??2011 by the Ecological Society of America.

Comparison of anesthetic agents in the sea otter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, T.D.; Kocher, F.H.

Five anesthetic agents (CI744, etorphine, fentanyl, ketamine hydrochloride, and halothane) were tested to establish the dosage of a safe, effective, short-acting anesthetic for use in the sea otter. Etorphine, at a dosage of 0.75 mg per adult otter and used in conjunction with diazepam, at a dosage of 1.25 mg per adult otter, met most of the requirements for use under field conditions. Halothane, administered through an anesthetic machine, proved to be effective for use in a veterinary hospital.

Sarcocysts of an unidentified species of Sarcocystis in the sea otter (Enhydra lutris)

USGS Publications Warehouse

Dubey, J.P.; Lindsay, D.S.; Rosenthal, B.M.; Thomas, N.J.

2003-01-01

The number of Sarcocystis species that infect sea otters (Enhydra lutris) is unknown. Sea otter tissues were recently shown to harbor sarcocysts of S. neurona and of unidentified species of Sarcocystis. Whereas sarcocysts of S. neurona have walls 1a??3 I?m thick with type 9 villar protrusions, ultrastructure of a distinct thin-walled sarcocyst (0.5a??0.7 I?m thick) lacking villar protrusions, but instead exhibiting minute type 1 undulations on the sarcocyst wall, is described in this report. Parasites characterized from a sea otter infection were inferred to be related to, but distinct from, other species belonging to Sarcocystis, based on sequencing and phylogenetic analysis of a portion of the beta subunit of the plastid-encoded RNA polymerase gene.

Mitochondrial-DNA variation among subspecies and populations of sea otters (Enhydra lutris)

USGS Publications Warehouse

Cronin, Matthew A.; Bodkin, James L.; Ballachey, Brenda E.; Estes, James A.; Patton, John C.

1996-01-01

We used restriction-enzyme analysis of polymerase-chain reaction-amplified, mitochondrial DNA (mtDNA) to assess genetic differentiation of subspecies and populations of sea otters, Enhydra lutris, throughout the range of the species. There were several haplotypes of mtDNA in each subspecies and geographically separate populations. MtDNA sequence divergence of haplotypes of sea otters was 0.0004–0.0041 base substitutions per nucleotide. E. L nereis appears to have monophyletic mitochondrial DNA, while E. I. lutris and E. I. kenyoni do not. Different frequencies of haplotypes of mtDNA among populations reflect current restriction of gene flow and the unique histories of different populations. There are two or three haplotypes of mtDNA and diversity of haplotypes is 0.1376–0.5854 in each population of otters. This is consistent with theoretical work, which suggests that population bottlenecks of sea otters probably did not result in major losses of genetic variation for individual populations, or the species as a whole.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballachey, B.E.

The study was conducted to evaluate several biomarkers of genotoxic damage in sea otters that had potentially been exposed to oil spilled from the Exxon Valdez. Thirteen adult male sea otters were captured in eastern (unoiled) Prince William Sound, and 14 in western (oiled) Prince William Sound in September and October 1991. Blood lymphocytes, sperm and testicular cells were collected from the otters for flow cytometric analyses to measure: (1) DNA content of lymphocytes, (2) nuclear chromatin structure of sperm, and (3) subpopulations of cell types in the testis. Additionally, sperm cells were examined by light microscopy for morphological abnormalities.more » The DNA content of blood lymphocytes from sea otters in the oiled vs. unoiled areas was not significantly different, although there was greater variation among samples from the oiled area. One measure of sperm cell quality was poorer for male sea otters from the unoiled area, and may have been associated with differences in the age and breeding status of the two groups sampled. Other measures of sperm and testicular cells did not differ between areas.« less

High-altitude diving in river otters: coping with combined hypoxic stresses.

PubMed

Crait, Jamie R; Prange, Henry D; Marshall, Noah A; Harlow, Henry J; Cotton, Clark J; Ben-David, Merav

2012-01-15

River otters (Lontra canadensis) are highly active, semi-aquatic mammals indigenous to a range of elevations and represent an appropriate model for assessing the physiological responses to diving at altitude. In this study, we performed blood gas analyses and compared blood chemistry of river otters from a high-elevation (2357 m) population at Yellowstone Lake with a sea-level population along the Pacific coast. Comparisons of oxygen dissociation curves (ODC) revealed no significant difference in hemoglobin-oxygen (Hb-O(2)) binding affinity between the two populations - potentially because of demands for tissue oxygenation. Instead, high-elevation otters had greater Hb concentrations (18.7 g dl(-1)) than sea-level otters (15.6 g dl(-1)). Yellowstone otters displayed higher levels of the vasodilator nitric oxide (NO), and half the concentration of the serum protein albumin, possibly to compensate for increased blood viscosity. Despite compensation in several hematological and serological parameters, theoretical aerobic dive limits (ADL) were similar between high-elevation and sea-level otters because of the lower availability of O(2) at altitude. Our results suggest that recent disruptions to the Yellowstone Lake food web could be detrimental to otters because at this high elevation, constraints on diving may limit their ability to switch to prey in a deep-water environment.

Using ecological function to develop recovery criteria for depleted species: Sea otters and kelp forests in the Aleutian archipelago

USGS Publications Warehouse

Estes, James A.; Tinker, M. Tim; Bodkin, James L.

2010-01-01

Recovery criteria for depleted species or populations normally are based on demographic measures, the goal being to maintain enough individuals over a sufficiently large area to assure a socially tolerable risk of future extinction. Such demographically based recovery criteria may be insufficient to restore the functional roles of strongly interacting species. We explored the idea of developing a recovery criterion for sea otters (Enhydra lutris) in the Aleutian archipelago on the basis of their keystone role in kelp forest ecosystems. We surveyed sea otters and rocky reef habitats at 34 island-time combinations. The system nearly always existed in either a kelp-dominated or deforested phase state, which was predictable from sea otter density. We used a resampling analysis of these data to show that the phase state at any particular island can be determined at 95% probability of correct classification with information from as few as six sites. When sea otter population status (and thus the phase state of the kelp forest) was allowed to vary randomly among islands, just 15 islands had to be sampled to estimate the true proportion that were kelp dominated (within 10%) with 90% confidence. We conclude that kelp forest phase state is a more appropriate, sensitive, and cost-effective measure of sea otter recovery than the more traditional demographically based metrics, and we suggest that similar approaches have broad potential utility in establishing recovery criteria for depleted populations of other functionally important species.

Foraging depths of sea otters and implications to coastal marine communities

USGS Publications Warehouse

Bodkin, James L.; Esslinger, George G.; Monson, Daniel H.

2004-01-01

We visually observed 1,251 dives, of 14 sea otters instrumented with TDRs in southeast Alaska, and used attribute values from observed dives to classify 180,848 recorded dives as foraging (0.64), or traveling (0.36). Foraging dives were significantly deeper, with longer durations, bottom times, and postdive surface intervals, and greater descent and ascent rates, compared to traveling dives. Most foraging occurred in depths between 2 and 30 m (0.84), although 0.16 of all foraging was between 30 and 100 m. Nine animals, including all five males, demonstrated bimodal patterns in foraging depths, with peaks between 5 and 15 m and 30 and 60 m, whereas five of nine females foraged at an average depth of 10 m. Mean shallow foraging depth was 8 m, and mean deep foraging depth was 44 m. Maximum foraging depths averaged 61 m (54 and 82 for females and males, respectively) and ranged from 35 to 100 m. Female sea otters dove to depths ≤20 m on 0.85 of their foraging dives while male sea otters dove to depths ≥45 m on 0.50 of their foraging dives. Less than 0.02 of all foraging dives were >55 m, suggesting that effects of sea otter foraging on nearshore marine communities should diminish at greater depths. However, recolonization of vacant habitat by high densities of adult male sea otters may result in initial reductions of some prey species at depths >55 m.

Temporal variations of natural and anthropogenic radionuclides in sea otter skull tissue in the North Pacific Ocean

USGS Publications Warehouse

Baskaran, M.; Hong, G.-H.; Dayton, S.; Bodkin, James L.; Kelley, J.J.

2002-01-01

Marine mammals being among the top predators in the food web tend to accumulate organic and inorganic contaminants from the environment. The body burden of contaminants in these species could reflect their foods and thus contaminant levels could serve as proxies on the changes of ecosystem. A pilot study was carried out to investigate the possibility of radionuclide leakage at Amchitka using a suite of sea otter (Enhydra lutris) skulls collected near Amchitka nuclear test-sites before (1950s) and after the testing (1990s), and at Adak, another Aleutian Island, about 300 km from Amchitka, where the potential impact of radionuclide leakage from Amchitka is expected to be negligible. In addition, the naturally occurring and anthropogenic radionuclide content on the sea otter skull was also utilized to investigate if there was any significant ecosystem changes in the environment.Concentration of 210Pb in sea otter bones collected during the 1950s was significantly higher than those collected in the 1990s. We propose that among the various factors that could cause this higher enrichment in 210Pb, changes in the sea otter prey is the most likely one. Comparison of the 137Cs, 90Sr, 239,240Pu concentrations appear not to be significantly higher in sea otter skulls collected in 1990s from Amchitka where the underground tests in 1965–71 than those from Adak, although significant differences were detected among different groups collected at various times.

Sarcocystis neurona infections in sea otter (Enhydra lutris): evidence for natural infections with sarcocysts and transmission of infection to opossums (Didelphis virginiana)

USGS Publications Warehouse

Dubey, J.P.; Rosypal, A.C.; Rosenthal, B.M.; Thomas, N.J.; Lindsay, D.S.; Stanek, J.F.; Reed, S.M.; Saville, W.J.A.

2001-01-01

Although Sarcocystis neurona has been identified in an array of terrestrial vertebrates, recent recognition of its capacity to infect marine mammals was unexpected. Here, sarcocysts from 2 naturally infected sea otters (Enhydra lutris) were characterized biologically, ultrastructurally, and genetically. DNA was extracted from frozen muscle of the first of these sea otters and was characterized as S. neurona by polymerase chain reation (PCR) amplification followed by restriction fragment length polymorphism analysis and sequencing. Sarcocysts from sea otter no. 1 were up to 350 I?m long, and the villar protrusions on the sarcocyst wall were up to 1.3 I?m long and up to 0.25 I?m wide. The villar protrusions were tapered towards the villar tip. Ultrastructurally, sarcocysts were similar to S. neurona sarcocysts from the muscles of cats experimentally infected with S. neurona sporocysts. Skeletal muscles from a second sea otter failed to support PCR amplification of markers considered diagnostic for S. neurona but did induce the shedding of sporocysts when fed to a laboratory-raised opossum (Didelphis virginiana). Such sporocysts were subsequently fed to knockout mice for the interferon-gamma gene, resulting in infections with an agent identified as S. neurona on the basis of immunohistochemistry, serum antibodies, and diagnostic sequence detection. Thus, sea otters exposed to S. neurona may support the development of mature sarcocysts that are infectious to competent definitive hosts.

Sea otter studies in Glacier Bay National Park and Preserve

USGS Publications Warehouse

Bodkin, James L.; Kloecker, Kimberly A.; Esslinger, George G.; Monson, Daniel H.; DeGroot, J.D.; Doherty, J.

2002-01-01

Following translocations to the outer coast of Southeast Alaska in 1965, sea otters have been expanding their range and increasing in abundance. We began conducting surveys for sea otters in Cross Sound, Icy Strait, and Glacier Bay, Alaska in 1994, following initial reports (in 1993) of their presence in Glacier Bay. Since 1995, the number of sea otters in Glacier Bay proper has increased from around 5 to more than 1500. Between 1993 and 1997 sea otters were apparently only occasional visitors to Glacier Bay, but in 1998 long-term residence was established as indicated by the presence of adult females and their dependent pups. Sea otter distribution is limited to the Lower Bay, south of Sandy Cove, and is not continuous within that area. Concentrations occur in the vicinity of Sita Reef and Boulder Island and between Pt. Carolus and Rush Pt. on the west side of the Bay (Figure 1). We describe the diet of sea otters during 2001 in Glacier Bay based on visual observations of prey during 456 successful forage dives. In Glacier Bay, diet consisted of 62% clam, 15% mussel, 9% crab, 7% unidentified, 4& urchins, and 4% other. Most prey recovered by sea otters are commercially, socially, or ecologically important species. Species of clam include Saxidomus gigantea, Protothaca staminea, and Mya truncata. Urchins are primarily Strongylocentrotus droebachiensis and the mussel is Modiolus modiolus. Crabs include species of three genera: Cancer, Chinoecetes, and Telmessus. Although we characterize diet at broad geographic scales, we found diet to vary between sites separated by as little as several hundred meters. Dietary variation among and within sites can reflect differences in prey availability and individual specialization. We estimated species composition, density, biomass, and sizes of subtidal clams, urchins, and mussels at 9 sites in lower Glacier Bay. All sites were selected based on the presence of abundant clam siphons. Sites were not selected to allow inference to any area larger than the sampling area (approx 400 m^2). Sites were selected to achieve a broad geographic sample of dense subtidal clam beds within Glacier Bay prior to occupation and foraging by sea otters. There was no direct evidence of otter foraging at any of our clam sampling sites. We sampled 11,568 bivalves representing 14 speces of clam and 2 species of mussel. We sampled 4,981 urchins, all Strongylocentrotus droeobachiensis. Only four species of clam (littleneck clams, Protothaca staminea; butter clams, Saxidomus gigantea; soft-shell claims, Mya truncata; and Macoma sp.) accounted for 91.6% of all clams sampled. Mean total clam density (#/0.25 m^2) across the 9 sites was 62.3. Densities (and se ) of P. staminea averaged 22.6 (1.6) and ranged from 0 to 97. Densities of S. gigantea averaged 14.4 (1.0) and ranged from 0 to 63. Densities of Macoma sp. averaged 14.5 (1.2) and ranged from 0 to 78. Densities of S. droebachiensis averaged 27.3 (1.7) and ranged from 0 to 109. Mean S. droebachiensis sizes ranged from 16 to 30 mm by site. Mean P. staminea sizes ranged from 30 to 53 mm, mean S. gigantea sizes ranged from 51 to 85 mm, and mean Macoma sp. sizes ranged from 14 to 19 mm. Although not the most abundant clam, S. gigantea contributed the greatest proportion to total clam biomass (63%), followed by P. staminea (24%). Sea otters are now well established in limited areas of the lower portions of Glacier Bay. It is likely that distribution and numbers of sea otters will continue to increase in Glacier Bay in the near future. Glacier Bay supports large and diverse populations of clams that are largely unexploited by sea otters presently. It is predictable that the density and sizes of clam populations will decline in response to otter predation. This will result in fewer opportunities for human harvest, but will also trigger ecosystem level changes, as prey for other predators, such as octopus, sea stars, fishes, birds and mammals are modified. Sea ott

Determining the pattern of cementum annuli and relationship to reproduction in male sea otters

USGS Publications Warehouse

Proper, Josh; von Biela, Vanessa R.; Burns, Jennifer M.

2007-01-01

Since the early 1990s, the southwestern Alaskan sea otter (Enhydra lutris) population has declined dramatically and the cause has yet to be determined. Population trajectories of large mammals are determined by three factors: survival rate, reproduction rate, and age of first reproduction (AFR). Of these three, AFR should respond first to environmental change. Life history theory predicts that AFR will be older with bottom-up causes (ie, food limitation) and younger when the cause of the decline is top-down (ie, predation), as there is usually abundant resources in this scenario. Traditionally, determining AFR required lethal sampling, which may not always be possible. Work on many mammalian species suggests that the width of annual cementum layers in teeth may decline when breeding begins. If so, examining teeth annuli may provide a nonlethal alternative for determining AFR. Ongoing research has shown this relationship in female sea otters, but male sea otters have not been tested. Sea otter testes and premolar teeth slides were collected by subsistence hunters working with the US Fish and Wildlife Service and the Alaska Sea Otter and Steller Sea Lion Commission from Alaska (1994– 2005). We determined the pattern in cementum annuli thickness for male sea otters across age by measuring annuli at three sites on each of the two slide sections available. We found that cementum annuli layers decreased with age, but found no correlation between cementum annuli and sexual maturity in male sea otters. This lack of correlation may be due to sampling error or different energy expenditures during reproduction for each sex. Since females expend large amounts of energy through gestation and lactation, we hypothesize that the width of female cementum annuli decreases at a much sharper rate when they reach AFR.The southwest Alaskan sea otter population has plummeted up to 90% since the early 1990s and the reason is unknown.1 Declines may be due to a bottom-up source caused by lack of food and habitat that occurs when populations are dense, in which case we would expect reproduction rates to decrease and age of first reproduction (AFR) to increase. However, circumstantial evidence suggests that the decline may be due to a top-down source, ie, predation.2 In this case, we would expect reproduction rates to increase and AFR to decrease due to lowered densities that coincide with top-down declines.3 An ongoing study of female sea otters has shown that past reproduction can be determined by analysis of cementum annuli in the teeth, and used to calculate AFR.4 Cementum annuli are annual deposits of minerals that occur on the root of a tooth that correspond to the growth of the animal (Figure 1). During summer and spring, growth is fast which accounts for the white area, but during winter, growth slows down and the cementum is compressed which accounts for a darkened line. In females, the relationship between cementum width declines and reproduction likely reflects the large expenditure of energy that is required during gestation and lactation. However, male and female mammals expend energy for reproduction in very distinct ways,3 and the same pattern of cementum decline may not be present in males. Since shifts in the life history strategy of males are poorly understood, we are interested in testing the relationship between cementum declines and reproduction in male sea otters using cementum analysis.

Detection of sea otters in boat-based surveys of Prince William Sound, Alaska. Marine mammal study 6-19. Exxon Valdez oil spill state/federal natural resource damage assessment final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Udevitz, M.S.; Bodkin, J.L.; Costa, D.P.

1995-05-01

Boat-based surveys were used to monitor the Prince William Sound sea otter population before and after the Exxon Valdez oil spill. Population and loss estimates could be obtained from these surveys by direct expansion from the counts in the surveyed transects under the assumption that all otters in those transects were observed. The authors conducted a pilot study using ground-based observers in conjunction with the August 1990 survey of marine mammals and birds to investigate the validity of this assumption. The proportion of otters detected by boat crews was estimated by comparing boat and ground-based observations on 22 segments ofmore » shoreline transects. Overall, the authors estimated that only 70% of the otters in surveyed shoreline transects were detected by the boat crews. These results suggest that unadjusted expansions of boat survey transect counts will underestimate sea otter population size and that loss estimates based on comparisons of unadjusted population estimates will be biased.« less

19 CFR 12.62 - Enforcement; duties of Customs officers.

Code of Federal Regulations, 2014 CFR

2014-04-01

...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.62 Enforcement... made pursuant thereto; and shall seize fur seals and sea otters, or the skins thereof, killed, captured...

19 CFR 12.62 - Enforcement; duties of Customs officers.

Code of Federal Regulations, 2011 CFR

2011-04-01

...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.62 Enforcement... made pursuant thereto; and shall seize fur seals and sea otters, or the skins thereof, killed, captured...

19 CFR 12.62 - Enforcement; duties of Customs officers.

Code of Federal Regulations, 2012 CFR

2012-04-01

...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.62 Enforcement... made pursuant thereto; and shall seize fur seals and sea otters, or the skins thereof, killed, captured...

19 CFR 12.62 - Enforcement; duties of Customs officers.

Code of Federal Regulations, 2013 CFR

2013-04-01

...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.62 Enforcement... made pursuant thereto; and shall seize fur seals and sea otters, or the skins thereof, killed, captured...

19 CFR 12.62 - Enforcement; duties of Customs officers.

Code of Federal Regulations, 2010 CFR

2010-04-01

...; DEPARTMENT OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.62 Enforcement... made pursuant thereto; and shall seize fur seals and sea otters, or the skins thereof, killed, captured...

The conservation of sea otters: a prelude

USGS Publications Warehouse

Bodkin, James L.; Larson, Shawn E.

2015-01-01

The story of sea otters over the past 275 years chronicles their decline to near extinction and the roads to recovery that cross various conflicts, and in the end provides lessons that will aid the conservation of other threatened species and compromised ecosystems. Sea otters inspire strong human emotions ranging from adoration to disdain. They are protected internationally, federally, and at state and local levels, yet still face a diversity of threats, representing the legacy of their decline as well as emerging consequences from the ever-deepening imprint of the human endeavor. Here we briefly introduce the species, chronicle its history of near-demise and subsequent recovery, and highlight several conservation successes and challenges. In this volume we bring together scientists with significant knowledge of and experience with the sea otter and its ecosystems to share lessons learned and consider how these might be used to aid in the enterprise of conservation more broadly.

Chemical anesthesia of Northern sea otters (Enhydra lutris): Results of past field studies

USGS Publications Warehouse

Monson, Daniel H.; McCormick, C.; Ballachey, Brenda E.

2001-01-01

Between 1987 and 1997, we chemically immobilized 597 wild sea otters (Enhydra lutris) in Alaska for the collection of biological samples or for surgical instrumentation. One drug-related sea otter fatality occurred during this time. Fentanyl in combination with diazepam produced consistent, smooth inductions with minimal need for supplemental anesthetics during procedures lasting 30-40 min. Antagonism with naltrexone or naloxone was rapid and complete, although we observed narcotic recycling in sea otters treated with naloxone. For surgical procedures, we recommend a fentanyl target dose of 0.33 mg/kg of body mass and diazepam at 0.11 mg/kg. For nonsurgical biological sample collection procedures, we recommend fentanyl at 0.22 mg/kg and diazepam at 0.07 mg/kg. We advise the use of the opioid antagonist naltrexone at a ratio of 2:1 to the total fentanyl administered during processing.

Testing the nutritional-limitation, predator-avoidance, and storm-avoidance hypotheses for restricted sea otter habitat use in the Aleutian Islands, Alaska

USGS Publications Warehouse

Stewart, Nathan L.; Konar, Brenda; Tinker, M. Tim

2015-01-01

Sea otters (Enhydra lutris) inhabiting the Aleutian Islands have stabilized at low abundance levels following a decline and currently exhibit restricted habitat-utilization patterns. Possible explanations for restricted habitat use by sea otters can be classified into two fundamentally different processes, bottom-up and top-down forcing. Bottom-up hypotheses argue that changes in the availability or nutritional quality of prey resources have led to the selective use of habitats that support the highest quality prey. In contrast, top-down hypotheses argue that increases in predation pressure from killer whales have led to the selective use of habitats that provide the most effective refuge from killer whale predation. A third hypothesis suggests that current restricted habitat use is based on a need for protection from storms. We tested all three hypotheses for restricted habitat use by comparing currently used and historically used sea otter foraging locations for: (1) prey availability and quality, (2) structural habitat complexity, and (3) exposure to prevailing storms. Our findings suggest that current use is based on physical habitat complexity and not on prey availability, prey quality, or protection from storms, providing further evidence for killer whale predation as a cause for restricted sea otter habitat use in the Aleutian Islands.

Testing the nutritional-limitation, predator-avoidance, and storm-avoidance hypotheses for restricted sea otter habitat use in the Aleutian Islands, Alaska.

PubMed

Stewart, Nathan L; Konar, Brenda; Tinker, M Tim

2015-03-01

Sea otters (Enhydra lutris) inhabiting the Aleutian Islands have stabilized at low abundance levels following a decline and currently exhibit restricted habitat-utilization patterns. Possible explanations for restricted habitat use by sea otters can be classified into two fundamentally different processes, bottom-up and top-down forcing. Bottom-up hypotheses argue that changes in the availability or nutritional quality of prey resources have led to the selective use of habitats that support the highest quality prey. In contrast, top-down hypotheses argue that increases in predation pressure from killer whales have led to the selective use of habitats that provide the most effective refuge from killer whale predation. A third hypothesis suggests that current restricted habitat use is based on a need for protection from storms. We tested all three hypotheses for restricted habitat use by comparing currently used and historically used sea otter foraging locations for: (1) prey availability and quality, (2) structural habitat complexity, and (3) exposure to prevailing storms. Our findings suggest that current use is based on physical habitat complexity and not on prey availability, prey quality, or protection from storms, providing further evidence for killer whale predation as a cause for restricted sea otter habitat use in the Aleutian Islands.

Age- and sex-specific mortality and population structure in sea otters

USGS Publications Warehouse

Bodkin, James L.; Burdin, A.M.; Ryazanov, D.A.

2000-01-01

We used 742 beach-cast carcasses to characterize age- and sex-specific sea otter mortality during the winter of 1990-1991 at Bering Island, Russia. We also examined 363 carcasses recovered after the 1989 grounding of the T/V Exxon Valdez, to characterize age and sex composition in the living western Prince William Sound (WPWS) sea otter population. At Bering Island, mortality was male-biased (81%), and 75% were adults. The WPWS population was female-biased (59%) and most animals were subadult (79% of the males and 45% of the females). In the decade prior to 1990-1991 we found increasing sea otter densities (particularly among males), declining prey resources, and declining weights in adult male sea otters at Bering Island. Our findings suggest the increased mortality at Bering Island in 1990-1991 was a density-dependent population response. We propose male-maintained breeding territories and exclusion of juvenile females by adult females, providing a mechanism for maintaining densities in female areas below densities in male areas and for potentially moderating the effects of prey reductions on the female population. Increased adult male mortality at Bering Island in 1990-1991 likely modified the sex and age class structure there toward that observed in Prince William Sound.

Dual Sarcocystis neurona and Toxoplasma gondii infection in a northern sea otter from Washington state, USA

USGS Publications Warehouse

Lindsay, D.S.; Thomas, N.J.; Rosypal, A.C.; Dubey, J.P.

2001-01-01

Dual Sarcocystis neurona and Toxoplasma gondii infection was observed in a Northern sea otter from Washington, USA. The animal was found stranded, convulsed, and died shortly thereafter. Encephalitis caused by both S. neurona and T. gondii was demonstrated in histological sections of brain. Immunohistochemical examination of sections with S. neurona specific antisera demonstrated developmental stages that divided by endopolygeny and produced numerous merozoites. PCR of brain tissue from the sea otter using primer pairs JNB33/JNB54 resulted in amplification of a 1100 bp product. This PCR product was cut in to 884 and 216 bp products by Dra I but was not cut by Hinf I indicating that it was S. neurona [J. Parasitol. 85 (1999) 221]. No PCR product was detected in the brain of a sea otter which had no lesions of encephalitis. Examination of brain sections using T. gondii specific antisera demonstrated tachyzoites and tissue cysts of T. gondii. The lesions induced by T. gondii suggested that the sea otter was suffering from reactivated toxoplasmosis. T. gondii was isolated in mice inoculated with brain tissue. A cat that was fed infected mouse brain tissue excreted T. gondii oocysts which were infective for mice. This is apparently the first report of dual S. neurona and T. gondii in a marine mammal.

77 FR 75265 - Endangered and Threatened Wildlife and Plants; Termination of the Southern Sea Otter...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-19

... designed and intended, we committed to a full and final evaluation of the program. We have now completed... its sea otter research project and would no longer be able to assist if we resumed capturing sea.... In light of our inability to implement the translocation program as designed and intended, we...

The interaction of intraspecific competition and habitat on individual diet specialization: a near range-wide examination of sea otters

USGS Publications Warehouse

Newsome, Seth D.; Tinker, M. Tim; Gill, Verena A.; Hoyt, Zachary N.; Doroff, Angela M.; Nichol, Linda; Bodkin, James L.

2015-01-01

The quantification of individuality is a common research theme in the fields of population, community, and evolutionary ecology. The potential for individuality to arise is likely context-dependent, and the influence of habitat characteristics on its prevalence has received less attention than intraspecific competition. We examined individual diet specialization in 16 sea otter (Enhydra lutris) populations from southern California to the Aleutian Islands in Alaska. Because population histories, relative densities, and habitat characteristics vary widely among sites, we could examine the effects of intraspecific competition and habitat on the prevalence of individual diet specialization. Using observed diet data, we classified half of our sites as rocky substrate habitats and the other half containing a mixture of rocky and unconsolidated (soft) sediment substrates. We used stable isotope data to quantify population- and individual-level diet variation. Among rocky substrate sites, the slope [±standard error (SE)] of the positive significant relationship between the within-individual component (WIC) and total isotopic niche width (TINW) was shallow (0.23 ± 0.07) and negatively correlated with sea otter density. In contrast, the slope of the positive WIC/TINW relationship for populations inhabiting mixed substrate habitats was much higher (0.53 ± 0.14), suggesting a low degree of individuality, irrespective of intraspecific competition. Our results show that the potential for individuality to occur as a result of increasing intraspecific competition is context-dependent and that habitat characteristics, which ultimately influence prey diversity, relative abundance, and the range of skillsets required for efficient prey procurement, are important in determining when and where individual diet specialization occurs in nature.

Experimental recovery of sea otter carcasses at Kodiak Island, Alaska, following the Exxon Valdez oil spill

USGS Publications Warehouse

DeGange, Anthony R.; Doroff, Angela M.; Monson, Daniel H.

1994-01-01

ound,  Alaska,  spilling  approximately  11  million  barrels  of  crude  oil.  Oil  wasdeposited  on  beaches  nearly  700  km  from  the  spill  site  (Galt  and  Payton  1990,Piatt  et  al.  1990),  affecting  thousands  of  hectares  of  sea  otter(Enhydra  lutris)habitat.  Two  of  the  principal  limitations  in  determining  the  initial  effects  of  theExxon  Valdez  oil  spill  on  sea  otter  populations  were  a  lack  of  recent  populationdata,  and  a  lack  of  information  on  the  proportion  of  the  total  number  of  seaotters  killed  by  the  spill  that  were  actually  recovered.ound,  Alaska,  spilling  approximately  11  million  barrels  of  crude  oil.  Oil  wasdeposited  on  beaches  nearly  700  km  from  the  spill  site  (Galt  and  Payton  1990,Piatt  et  al.  1990),  affecting  thousands  of  hectares  of  sea  otter(Enhydra  lutris)habitat.  Two  of  the  principal  limitations  in  determining  the  initial  effects  of  theExxon  Valdez  oil  spill  on  sea  otter  populations  were  a  lack  of  recent  populationdata,  and  a  lack  of  information  on  the  proportion  of  the  total  number  of  seaotters  killed  by  the  spill  that  were  actually  recovered.On 24 March 1989, the T/V Exxon Valdez ran aground in Prince William Sound, Alaska, spilling approximately 11 million barrels of crude oil. Oil was deposited on beaches nearly 700 km from the spill site (Galt and Payton 1990, Piatt et al. 1990), affecting thousands of hectares of sea otter (Enhydra lutris) habitat. Two of the principal limitations in determining the initial effects of the Exxon Valdez oil spill on sea otter populations were a lack of recent population data, and a lack of information on the proportion of the total number of sea otters killed by the spill that were actually recovered.In late April and early May oil spread to the Kodiak Archipelago. With the oil came wildlife rescue, beach cleanup, and other spill-response activities including searches for dead birds and mammals. We took this opportunity to assess experimentally the recovery of sea otter carcasses in the Kodiak Island area. Specifically, we were interested in the proportion of the total number of dead sea otters the recovered carcasses represented.

Use of historically fishless high-mountain lakes and streams by neartic River Otters (Lontra canadensis) in California

Treesearch

Justin M. Garwood; Roland A. Knapp; Karen L. Pope; Robert L. Grasso; Michael L. Magnuson; Jeff R. Maurer

2013-01-01

In California, River Otters (Lontra canadensis) are most commonly associated with food-rich lowland aquatic habitats where they forage primarily on fish and crustaceans. Their distribution in high-elevation montane regions of the state, areas in which fish and crayfish were absent historically, is largely unknown.We compiled occurrence records of...

Catastrophes and conservation: Lessons from sea otters and the Exxon Valdez

DOE Office of Scientific and Technical Information (OSTI.GOV)

Estes, J.A.

1991-12-13

In this commentary, the author considers the effort to save sea otters after the Exxon Valdez oil spill. Despite immense expenditures, the emerging facts lead to two conclusions: population losses were poorly documented, and few animals were saved. These findings cast doubt on our ability to protect sea otters from future spills and lead to troubling questions about how to recognize and document the effects of catastrophic events, and, ultimately, the utility of highly visible and expensive efforts to save wildlife from perceived environmental catastrophes. On 24 March 1989, the Exxon Valdez ran aground on Bligh Reef in northeastern Princemore » William Sound, spilling more than 10 million gallons of crude oil. Catastrophic losses were expected and a monumental effort was made to save sea otters. The Exxon Valdez spill spread over a linear distance of more than 700 kilometers and soiled an estimated 5,300 kilometers of shoreline. While cleaning up and capturing oiled wildlife for rehabilitation, 878 sea otter carcasses were recovered - a minimal estimate of loss. However, many animals killed by the spill undoubtedly were not found. Losses have been estimated from pre- and post-spill surveys, although these surveys shed little light on the population-level effect, mainly because the size and distribution of the population just prior to the spill is poorly known. This is because a comprehensive survey of Prince William Sound and adjacent waters was not done immediately after the spill but before oil dispersed into southwestern Prince William Sound and the northern Gulf of Alaska. Thus, although the Exxon Valdez spill undoubtedly killed many sea otters and may have reduced populations substantially, available data lack the power to demonstrate population changes.« less

Exposure of sea otters and harlequin ducks in Prince William Sound, Alaska, USA, to shoreline oil residues 20 years after the Exxon Valdez oil spill.

PubMed

Neff, Jerry M; Page, David S; Boehm, Paul D

2011-03-01

We assessed whether sea otters and harlequin ducks in an area of western Prince William Sound, Alaska, USA (PWS), oiled by the 1989 Exxon Valdez oil spill (EVOS), are exposed to polycyclic aromatic hydrocarbons (PAH) from oil residues 20 years after the spill. Spilled oil has persisted in PWS for two decades as surface oil residues (SOR) and subsurface oil residues (SSOR) on the shore. The rare SOR are located primarily on the upper shore as inert, nonhazardous asphaltic deposits, and SSOR are confined to widely scattered locations as small patches under a boulder/cobble veneer, primarily on the middle and upper shore, in forms and locations that preclude physical contact by wildlife and diminish bioavailability. Sea otters and harlequin ducks consume benthic invertebrates that they collect by diving to the bottom in the intertidal and subtidal zones. Sea otters also dig intertidal and subtidal pits in search of clams. The three plausible exposure pathways are through the water, in oil-contaminated prey, or by direct contact with SSOR during foraging. Concentrations of PAH in near-shore water off oiled shores in 2002 to 2005 were at background levels (<0.05 ng/L). Median concentrations of PAH in five intertidal prey species on oiled shores in 2002 to 2008 range from 4.0 to 34 ng/g dry weight, indistinguishable from background concentrations. Subsurface oil residues are restricted to locations on the shore and substrate types, where large clams do not occur and where sea otters do not dig foraging pits. Therefore, that sea otters and harlequin ducks continue to be exposed to environmentally significant amounts of PAH from EVOS 20 years after the spill is not plausible. Copyright © 2010 SETAC.

Inter-decadal patterns of population and dietary change in sea otters at Amchitka Island, Alaska

USGS Publications Warehouse

Watt, J.; Siniff, D.B.; Estes, J.A.

2000-01-01

After having been hunted to near-extinction in the Pacific maritime fur trade, the sea otter population at Amchitka Island, Alaska increased from very low numbers in the early 1900s to near equilibrium density by the 1940s. The population persisted at or near equilibrium through the 1980s, but declined sharply in the 1990s in apparent response to increased killer whale predation. Sea otter diet and foraging behavior were studied at Amchitka from August 1992 to March 1994 and the data compared with similar information obtained during several earlier periods. In contrast with dietary patterns in the 1960s and 1970s, when the sea otter population was at or near equilibrium density and kelp-forest fishes were the dietary mainstay, these fishes were rarely eaten in the 1990s. Benthic invertebrates, particularly sea urchins, dominated the otter's diet from early summer to midwinter, then decreased in importance during late winter and spring when numerous Pacific smooth lumpsuckers (a large and easily captured oceanic fish) were eaten. The occurrence of spawning lumpsuckers in coastal waters apparently is episodic on a scale of years to decades. The otters' recent dietary shift away from kelp-forest fishes is probably a response to the increased availability of lumpsuckers and sea urchins (both high-preference prey). Additionally, increased urchin densities have reduced kelp beds, thus further reducing the availability of kelp-forest fishes. Our findings suggest that dietary patterns reflect changes in population status and show how an ecosystem normally under top-down control and limited by coastal zone processes can be significantly perturbed by exogenous events.

Setting realistic recovery targets for two interacting endangered species, sea otter and northern abalone.

PubMed

Chadès, Iadine; Curtis, Janelle M R; Martin, Tara G

2012-12-01

Failure to account for interactions between endangered species may lead to unexpected population dynamics, inefficient management strategies, waste of scarce resources, and, at worst, increased extinction risk. The importance of species interactions is undisputed, yet recovery targets generally do not account for such interactions. This shortcoming is a consequence of species-centered legislation, but also of uncertainty surrounding the dynamics of species interactions and the complexity of modeling such interactions. The northern sea otter (Enhydra lutris kenyoni) and one of its preferred prey, northern abalone (Haliotis kamtschatkana), are endangered species for which recovery strategies have been developed without consideration of their strong predator-prey interactions. Using simulation-based optimization procedures from artificial intelligence, namely reinforcement learning and stochastic dynamic programming, we combined sea otter and northern abalone population models with functional-response models and examined how different management actions affect population dynamics and the likelihood of achieving recovery targets for each species through time. Recovery targets for these interacting species were difficult to achieve simultaneously in the absence of management. Although sea otters were predicted to recover, achieving abalone recovery targets failed even when threats to abalone such as predation and poaching were reduced. A management strategy entailing a 50% reduction in the poaching of northern abalone was a minimum requirement to reach short-term recovery goals for northern abalone when sea otters were present. Removing sea otters had a marginally positive effect on the abalone population but only when we assumed a functional response with strong predation pressure. Our optimization method could be applied more generally to any interacting threatened or invasive species for which there are multiple conservation objectives. © 2012 Society for Conservation Biology.

Sea otter research methods and tools

USGS Publications Warehouse

Bodkin, James L.; Maldini, Daniela; Calkins, Donald; Atkinson, Shannon; Meehan, Rosa

2004-01-01

Sea otters possess physical characteristics and life history attributes that provide both opportunity and constraint to their study. Because of their relatively limited diving ability they occur in nearshore marine habitats that are usually viewable from shore, allowing direct observation of most behaviors. Because sea otters live nearshore and forage on benthic invertebrates, foraging success and diet are easily measured. Because they rely almost exclusively on their pelage for insulation, which requires frequent grooming, successful application of external tags or instruments has been limited to attachments in the interdigital webbing of the hind flippers. Techniques to surgically implant instruments into the intraperitoneal cavity are well developed and routinely applied. Because they have relatively small home ranges and rest in predictable areas, they can be recaptured with some predictability using closed-circuit scuba diving technology. The purpose of this summary is to identify some of the approaches, methods, and tools that are currently engaged for the study of sea otters, and to suggest potential avenues for applying advancing technologies.

Epidemiology and pathology of Toxoplasma gondii in free-ranging California sea lions (Zalophus californianus).

PubMed

Carlson-Bremer, Daphne; Colegrove, Kathleen M; Gulland, Frances M D; Conrad, Patricia A; Mazet, Jonna A K; Johnson, Christine K

2015-04-01

The coccidian parasite Toxoplasma gondii infects humans and warm-blooded animals worldwide. The ecology of this parasite in marine systems is poorly understood, although many marine mammals are infected and susceptible to clinical toxoplasmosis. We summarized the lesions associated with T. gondii infection in the California sea lion (Zalophus californianus) population and investigated the prevalence of and risk factors associated with T. gondii exposure, as indicated by antibody. Five confirmed and four suspected cases of T. gondii infection were identified by analysis of 1,152 medical records of necropsied sea lions from 1975-2009. One suspected and two confirmed cases were identified in aborted fetuses from a sea lion rookery. Toxoplasmosis was the primary cause of death in five cases, including the two fetuses. Gross and histopathologic findings in T. gondii-infected sea lions were similar to those reported in other marine mammals. The most common lesions were encephalitis, meningitis, and myocarditis. The antibody prevalence in stranded, free-ranging sea lions for 1998-2009 was 2.5% (±0.03%; IgG titer 640). There was an increase in odds of exposure in sea lions with increasing age, suggesting cumulative risk of exposure and persistent antibody over time. The occurrence of disseminated T. gondii infection in aborted fetuses confirms vertical transmission in sea lions, and the increasing odds of exposure with age is consistent with additional opportunities for horizontal transmission in free-ranging sea lions over time. These data suggest that T. gondii may have two modes of transmission in the sea lion population. Overall, clinical disease was uncommon in our study which, along with low prevalence of T. gondii antibody, suggests substantially less-frequent exposure and lower susceptibility to clinical disease in California sea lions as compared to sympatric southern sea otters (Enhydra lutris nereis).

Variation in δ13C and δ15N diet–vibrissae trophic discrimination factors in a wild population of California sea otters

USGS Publications Warehouse

Newsome, Seth D.; Bentall, Gena B.; Tinker, M. Tim; Oftedal, Olav T.; Ralls, Katherine; Estes, James A.; Fogel, Marilyn L.

2010-01-01

The ability to quantify dietary inputs using stable isotope data depends on accurate estimates of isotopic differences between a consumer (c) and its diet (d), commonly referred to as trophic discrimination factors (TDFs) and denoted by Δc-d. At present, TDFs are available for only a few mammals and are usually derived in captive settings. The magnitude of TDFs and the degree to which they vary in wild populations is unknown. We determined δ13C and δ15N TDFs for vibrissae (i.e., whiskers), a tissue that is rapidly becoming an informative isotopic substrate for ecologists, of a wild population of sea otters for which individual diet has been quantified through extensive observational study. This is one of the very few studies that report TDFs for free-living wild animals feeding on natural diets. Trophic discrimination factors of 2.2‰ ± 0.7‰ for δ13C and 3.5‰ ± 0.6‰ for δ15N (mean ± SD) were similar to those reported for captive carnivores, and variation in individual δ13C TDFs was negatively but significantly related to sea urchin consumption. This pattern may relate to the lipid-rich diet consumed by most sea otters in this population and suggests that it may not be appropriate to lipid-extract prey samples when using the isotopic composition of keratinaceous tissues to examine diet in consumers that frequently consume lipid-rich foods, such as many marine mammals and seabirds. We suggest that inherent variation in TDFs should be included in isotopically based estimates of trophic level, food chain length, and mixing models used to quantify dietary inputs in wild populations; this practice will further define the capabilities and limitations of isotopic approaches in ecological studies.

Evidence for a novel marine harmful algal bloom: Cyanotoxin (Microcystin) transfer from land to sea otters

USGS Publications Warehouse

Miller, Melissa A.; Kudela, Raphael M.; Mekebri, Abdu; Crane, Dave; Oates, Stori C.; Tinker, M. Timothy; Staedler, Michelle; Miller, Woutrina A.; Toy-Choutka, Sharon; Dominik, Clare; Hardin, Dane; Langlois, Gregg; Murray, Michael; Ward, Kim; Jessup, David A.

2010-01-01

"Super-blooms" of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrates as the most likely route of exposure. This hypothesis was evaluated through environmental detection of potential freshwater and marine microcystin sources, sea otter necropsy with biochemical analysis of tissues and evaluation of bioaccumulation of freshwater microcystins by marine invertebrates. Ocean discharge of freshwater microcystins was confirmed for three nutrient-impaired rivers flowing into the Monterey Bay National Marine Sanctuary, and microcystin concentrations up to 2,900 ppm (2.9 million ppb) were detected in a freshwater lake and downstream tributaries to within 1 km of the ocean. Deaths of 21 southern sea otters, a federally listed threatened species, were linked to microcystin intoxication. Finally, farmed and free-living marine clams, mussels and oysters of species that are often consumed by sea otters and humans exhibited significant biomagnification (to 107 times ambient water levels) and slow depuration of freshwater cyanotoxins, suggesting a potentially serious environmental and public health threat that extends from the lowest trophic levels of nutrient-impaired freshwater habitat to apex marine predators. Microcystin-poisoned sea otters were commonly recovered near river mouths and harbors and contaminated marine bivalves were implicated as the most likely source of this potent hepatotoxin for wild otters. This is the first report of deaths of marine mammals due to cyanotoxins and confirms the existence of a novel class of marine "harmful algal bloom" in the Pacific coastal environment; that of hepatotoxic shellfish poisoning (HSP), suggesting that animals and humans are at risk from microcystin poisoning when consuming shellfish harvested at the land-sea interface.

Evidence for a Novel Marine Harmful Algal Bloom: Cyanotoxin (Microcystin) Transfer from Land to Sea Otters

PubMed Central

Miller, Melissa A.; Kudela, Raphael M.; Mekebri, Abdu; Crane, Dave; Oates, Stori C.; Tinker, M. Timothy; Staedler, Michelle; Miller, Woutrina A.; Toy-Choutka, Sharon; Dominik, Clare; Hardin, Dane; Langlois, Gregg; Murray, Michael; Ward, Kim; Jessup, David A.

2010-01-01

“Super-blooms” of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrates as the most likely route of exposure. This hypothesis was evaluated through environmental detection of potential freshwater and marine microcystin sources, sea otter necropsy with biochemical analysis of tissues and evaluation of bioaccumulation of freshwater microcystins by marine invertebrates. Ocean discharge of freshwater microcystins was confirmed for three nutrient-impaired rivers flowing into the Monterey Bay National Marine Sanctuary, and microcystin concentrations up to 2,900 ppm (2.9 million ppb) were detected in a freshwater lake and downstream tributaries to within 1 km of the ocean. Deaths of 21 southern sea otters, a federally listed threatened species, were linked to microcystin intoxication. Finally, farmed and free-living marine clams, mussels and oysters of species that are often consumed by sea otters and humans exhibited significant biomagnification (to 107 times ambient water levels) and slow depuration of freshwater cyanotoxins, suggesting a potentially serious environmental and public health threat that extends from the lowest trophic levels of nutrient-impaired freshwater habitat to apex marine predators. Microcystin-poisoned sea otters were commonly recovered near river mouths and harbors and contaminated marine bivalves were implicated as the most likely source of this potent hepatotoxin for wild otters. This is the first report of deaths of marine mammals due to cyanotoxins and confirms the existence of a novel class of marine “harmful algal bloom” in the Pacific coastal environment; that of hepatotoxic shellfish poisoning (HSP), suggesting that animals and humans are at risk from microcystin poisoning when consuming shellfish harvested at the land-sea interface. PMID:20844747

76 FR 68438 - Environmental Impacts Statements; Notice of Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-04

... Los Angeles River between Mateo and Mill Streets, Los Angeles County, CA, Review Period Ends: 12/05..., USFWS, CA, Southern Sea Otters (Enhydra lutris nereis) Translocation Program, Updated Information to the.../species_information/so_sea_otter/index.html . Revision of FR Notice Published 08/26/2011: Reopening...

Temporal patterns in the foraging behavior of sea otters in Alaska

USGS Publications Warehouse

Esslinger, George G.; Bodkin, James L.; Breton, André R.; Burns, Jennifer M.; Monson, Daniel H.

2014-01-01

Activity time budgets in apex predators have been proposed as indicators of population status relative to resource limitation or carrying capacity. We used archival time-depth recorders implanted in 15 adult female and 4 male sea otters (Enhydra lutris) from the northernmost population of the species, Prince William Sound, Alaska, USA, to examine temporal patterns in their foraging behavior. Sea otters that we sampled spent less time foraging during summer (females 8.8 hr/day, males 7.9 hr/day) than other seasons (females 10.1–10.5 hr/day, males 9.2–9.5 hr/day). Both sexes showed strong preferences for diurnal foraging and adjusted their foraging effort in response to the amount of available daylight. One exception to this diurnal foraging mode occurred after females gave birth. For approximately 3 weeks post-partum, females switched to nocturnal foraging, possibly in an effort to reduce the risk of predation by eagles on newborn pups. We used multilevel mixed regression models to assess the contribution of several biological and environmental covariates to variation in the daily foraging effort of parous females. In the random effects only model, 87% of the total variation in foraging effort was within-otter variation. The relatively small among-otter variance component (13%) indicates substantial consistency in the foraging effort of sea otters in this northern population. In the top 3 models, 17% of the within-otter variation was explained by reproductive stage, day length, wind speed, air temperature and a wind speed × air temperature interaction. This study demonstrates the potential importance of environmental and reproductive effects when using activity budgets to assess population status relative to carrying capacity.

Pathogen exposure and blood chemistry in the Washington population of northern sea otters (Enhydra lutris kenyoni)

USGS Publications Warehouse

White, C. LeAnn; Schuler, Krysten L.; Thomas, Nancy J.; Webb, Julie L.; Saliki, Jeremiah T.; Ip, Hon S.; Dubey, J.P.; Frame, Elizabeth R.

2013-01-01

Northern sea otters (Enhydra lutris kenyoni) from Washington State, United States were evaluated in 2011 to determine health status and pathogen exposure. Antibodies to Brucella spp. (10%) and influenza A virus (23%) were detected for the first time in this population in 2011. Changes in clinical pathology values (serum chemistries), exposure to pathogens, and overall health of the population over the last decade were assessed by comparing 2011 data to the data collected on this population in 2001–2002. Several serum chemistry parameters were different between study years and sexes but were not clinically significant. The odds of canine distemper virus exposure were higher for otters sampled in 2001–2002 (80%) compared to 2011 (10%); likelihood of exposure significantly increased with age. Prevalence of exposure to Sarcocystis neurona was also higher in 2001–2002 (29%) than in 2011 (0%), but because testing methods varied between study years the results were not directly comparable. Exposure to Leptospira spp. was only observed in 2001–2002. Odds of Toxoplasma gondii exposure were higher for otters sampled in 2011 (97%) than otters in 2001–2002 (58%). Substantial levels of domoic acid (n = 2) and saxitoxin (n = 2) were found in urine or fecal samples from animals sampled in 2011. No evidence of calicivirus or Coxiella burnetii exposure in the Washington population of northern sea otters was found in either 2001–2002 or 2011. Changes in exposure status from 2001–2002 to 2011 suggest that the Washington sea otter population may be dealing with new disease threats (e.g., influenza) while also increasing their susceptibility to diseases that may be highly pathogenic in naïve individuals (e.g., canine distemper).

Assessment of clinical pathology and pathogen exposure in sea otters (Enhydra lutris) bordering the threatened population in Alaska

USGS Publications Warehouse

Goldstein, Tracey; Gill, Verena A.; Tuomi, Pamela A.; Monson, Daniel H.; Burdin, Alexander; Conrad, Patricia A.; Dunn, J. Lawrence; Field, Cara L.; Johnson, Christine K.; Jessup, David A.; Bodkin, James L.; Doroff, Angela M.

2011-01-01

Northern sea otter (Enhydra lutris kenyoni) abundance has decreased dramatically over portions of southwest Alaska, USA, since the mid-1980s, and this stock is currently listed as threatened under the Endangered Species Act. In contrast, adjacent populations in south central Alaska, USA, and Russia have been stable to increasing during the same period. Sea otters bordering the area classified in the recent decline were live-captured during 2004–2006 at Bering Island, Russia, and the Kodiak Archipelago, Alaska, USA, to evaluate differences in general health and current exposure status to marine and terrestrial pathogens. Although body condition was lower in animals captured at Bering Island, Russia, than it was at Kodiak, USA, clinical pathology values did not reveal differences in general health between the two regions. Low prevalences of antibodies (>5%) were found in Kodiak, USA, and on Bering Island, Russia, to Toxoplasma gondii, Sarcocystis neurona, and Leptospira interrogans. Exposure to phocine herpesvirus-1 was found in both Kodiak, USA (15.2%), and Bering Island, Russia (2.3%). Antibodies to Brucella spp. were found in 28% of the otters tested on Bering Island, Russia, compared with only 2.7% of the samples from Kodiak, USA. Prevalence of exposure to Phocine distemper virus (PDV) was 41% in Kodiak, USA, but 0% on Bering Island, Russia. Archived sera from southwest and south-central Alaska dating back to 1989 were negative for PDV, indicating exposure occurred in sea otters in Kodiak, USA, in recent years. Because PDV can be highly pathogenic in naïve and susceptible marine mammal populations, tissues should be examined to explore the contribution of this virus to otter deaths. Our results reveal an increase in exposure to pathogens in sea otters in Kodiak, Alaska, USA, since the 1990s.

19 CFR 12.60 - Importation prohibited.

Code of Federal Regulations, 2014 CFR

2014-04-01

... TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.60 Importation prohibited. The transportation, importation, sale, or possession of the skins of fur seals or sea otters is prohibited if such skins were taken contrary to the provisions of section 2 of the act of February 26, 1944 (58 Stat. 100...

19 CFR 12.60 - Importation prohibited.

Code of Federal Regulations, 2012 CFR

2012-04-01

... TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.60 Importation prohibited. The transportation, importation, sale, or possession of the skins of fur seals or sea otters is prohibited if such skins were taken contrary to the provisions of section 2 of the act of February 26, 1944 (58 Stat. 100...

19 CFR 12.60 - Importation prohibited.

Code of Federal Regulations, 2011 CFR

2011-04-01

... TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.60 Importation prohibited. The transportation, importation, sale, or possession of the skins of fur seals or sea otters is prohibited if such skins were taken contrary to the provisions of section 2 of the act of February 26, 1944 (58 Stat. 100...

19 CFR 12.60 - Importation prohibited.

Code of Federal Regulations, 2013 CFR

2013-04-01

... TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.60 Importation prohibited. The transportation, importation, sale, or possession of the skins of fur seals or sea otters is prohibited if such skins were taken contrary to the provisions of section 2 of the act of February 26, 1944 (58 Stat. 100...

19 CFR 12.60 - Importation prohibited.

Code of Federal Regulations, 2010 CFR

2010-04-01

... TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.60 Importation prohibited. The transportation, importation, sale, or possession of the skins of fur seals or sea otters is prohibited if such skins were taken contrary to the provisions of section 2 of the act of February 26, 1944 (58 Stat. 100...

Pathogen exposure and blood chemistry in the Washington population of northern sea otters (Enhydra lutris kenyoni)

USDA-ARS?s Scientific Manuscript database

Northern sea otters (Enhydra lutris kenyoni) from Washington State were evaluated in 2011 to determine health status and pathogen exposure. Antibodies to Brucella spp. (10%) and influenza A (23%) were detected for the first time in this population in 2011. Changes in clinical pathology values (serum...

Brucella Infection in Asian Sea Otters (Enhydra lutris lutris) on Bering Island, Russia.

PubMed

Burgess, Tristan L; Johnson, Christine Kreuder; Burdin, Alexander; Gill, Verena A; Doroff, Angela M; Tuomi, Pamela; Smith, Woutrina A; Goldstein, Tracey

2017-10-01

Infection with Brucella spp., long known as a cause of abortion, infertility, and reproductive loss in domestic livestock, has increasingly been documented in marine mammals over the past two decades. We report molecular evidence of Brucella infection in Asian sea otters (Enhydra lutris lutris). Brucella DNA was detected in 3 of 78 (4%) rectal swab samples collected between 2004 and 2006 on Bering Island, Russia. These 78 animals had previously been documented to have a Brucella seroprevalence of 28%, markedly higher than the prevalence documented in sea otters (Enhydra lutris) in North America. All of the DNA sequences amplified were identical to one or more previously isolated Brucella spp. including strains from both terrestrial and marine hosts. Phylogenetic analysis of this sequence suggested that one animal was shedding Brucella spp. DNA with a sequence matching a Brucella abortus strain, whereas two animals yielded a sequence matching a group of strains including isolates classified as Brucella pinnipedialis and Brucella melitensis. Our results highlight the diversity of Brucella spp. within a single sea otter population.

Age-specific reproduction in female sea otters (Enhydra lutris) from south-central Alaska: Analysis of reproductive tracts

USGS Publications Warehouse

Bodkin, James L.; Mulcahy, Daniel M.; Lensink, Calvin J.

1993-01-01

We estimated age at sexual maturity and age-specific reproductive rates by examining carcasses and reproductive tracts from 177 female sea otters (Enhydra lutris). Carcasses were recovered from south-central Alaska, Primarily from western Prince William Sound, as a result of the T/V Exxon Valdez oil spill in 1989. We found 65% of our sample to be sexually mature. Sexual maturity was first attained at age 2. The proportion of sexually mature animals increased from 30% at age 2 to 100% at age 5. Annual reproductive rates increased from 22% at age 2 to 78% at age 5 and remained relatively stable (75-88%) through to age 15. the sex ratio (female:male) of 49 fetal sea otters was 18:37 and differed significantly from parity. Females younger than 8 tended to produce more female fetuses, while older mothers did not. Our estimates of the reproductive characteristics of female sea otters obtained by examination of reproductive tracts were similiar to those reported in the literature based on in situ observations of marked individuals.

Clinical and clinical laboratory correlates in sea otters dying unexpectedly in rehabilitation centers following the Exxon Valdez oil spill

USGS Publications Warehouse

Rebar, A.H.; Lipscomb, T.P.; Harris, R.K.; Ballachey, Brenda E.

1995-01-01

Following the Exxon Valdez oil spill, 347 oiled sea otters (Enhydra lutris) were treated in rehabilitation centers. Of these, 116 died, 94 within 10 days of presentation. Clinical records of 21 otters dying during the first 10 days of rehabilitation were reviewed to define the laboratory abnormalities and clinical syndromes associated with these unexpected deaths. The most common terminal syndrome was shock characterized by hypothermia, lethargy, and often hemorrhagic diarrhea. In heavily and moderately oiled otters, shock developed within 48 hours of initial presentation, whereas in lightly oiled otters shock generally occurred during the second week of captivity. Accompanying laboratory abnormalities included leukopenia with increased numbers of immature neutrophils (degenerative left shift), lymphopenia, anemia, azotemia (primarily prerenal), hyperkalemia, hypoproteinemia/hypoalbuminemia, elevations of serum transaminases, and hypoglycemia. Shock associated with hemorrhagic diarrhea probably occurred either as a direct primary effect of oiling or as an indirect effect secondary to confinement and handling in the rehabilitation centers. Lightly oiled otters were less likely to die from shock than were heavily oiled otters (22% vs. 72%, respectively). Heavily oiled otters developed shock more rapidly and had greater numbers of laboratory abnormalities, suggesting that exposure to oil was an important contributing factor.

Sea otter studies in Glacier Bay National Park and Preserve: Aerial surveys, foraging observations, and intertidal clam sampling

USGS Publications Warehouse

Bodkin, James L.; Kloecker, Kimberly A.; Esslinger, George G.; Monson, Daniel H.; DeGroot, J.D.

2001-01-01

Following translocations to the outer coast of Southeast Alaska in 1965, sea otters have been expanding their range and increasing in abundance. We began conducting surveys for sea otters in Cross Sound, Icy Strait and Glacier Bay, Alaska in 1994, following initial reports of their presence in Glacier Bay in 1993. Since 1995, the number of sea otters in Glacier Bay proper has increased from about 5 to more than 500. Between 1993 and 1997 sea otters were apparently only occasional visitors to Glacier Bay, but in 1998 long-term residence was established as indicated by the presence of adult females and their dependent pups. Sea otter distribution is limited to the Lower Bay, south of Sandy Cove, and is not continuous within that area. Concentration occur in the vicinity of Sita Reef and Boulder Island and between Pt. Carolus and Rush Pt. on the west side of the Bay (Figure 1). We describe the diet of sea otters in Glacier Bay and south Icy Strait through visual observations of prey during >4,000 successful forage dives. In 2,399 successful foraging dives observed in Glacier Bay proper, diet consisted of 40% clam, 21% urchins, 18% mussel, 4% crab, 5% other and 12% unidentified. Most prey recovered by sea otters are commercially, socially, or ecological important species. Species of clam are primarily Saxidomus gigantea, Protothaca staminea, and Serripes groenlandicus. Urchins are primarily Strongylocentrotus droebachiensis while both mussles, Modiolus modiolus and Mytilus trossulus, are taken. Crabs include species of Cancer, Chinoecetes, Paralithodes, and Telmessus. Although we characterize diet at broad geographic scales, we found diet to vary between sites separated by as little as several hundred meters. Dietary variation among and within sites can reflect differences in prey availability and individual choice.We estimated species composition, density, biomass, and sizes of intertidal clams at 59 sites in Glacier Bay, 14 sites in Idaho Inlet, 12 sites in Port Althorp and 2 sites in Dundas Bay. There is no direct evidence of otter foraging at any of our clam sampling sites except at Port Althorp where sea otters have been present for >20 years and regularly forage intertidally. There is some indication of intertidal foraging in Idaho Inlet, based on reduced mean size of preferred clam species. Sea otters have been present in Idaho Inlet for at least 12 years. We sampled 48 systematically selected sites to allow inference throughout Glacier Bay intertidal areas and 12 preferred habitat intertidal sites to estimate maximum clam densities in the Bay. We also sampled 14 and 12 random sites in Idaho Inlet and Port Althorp, respectively, to provide contrast between sites with and without sea otters. Densities and biomass of intertidal clams were greater in the Lower Bay than either the East or West Arms. Mean densities (#/0.25m2) of all species of clams > 10.0 mm total length were 96.5 at preferred sites, 32.8 in the Lower Bay, 12.2 in the East Arm, 6.6 in the West Arm, 11.32 at Port Althorp and 27.1 at Idaho Inlet. Clam densities were lower in the Upper Arms of Glacier Bay, compared to the Lower Bay and were similar to densities at Port Althorp. In the Lower Bay, clam densities were nearly twice as high at preferred clam sites compared to those systematically sampled. Species of Macoma were the numerically dominant intertidal clam at most sites in Glacier Bay, while Protothaca staminea was dominant at Idaho Inlet and Port Althorp. Biomas (g/0.25m2) was higher in the Lower Bay (23.5) than either Arm (2.1 and .91) and higher at preferred sites (73.4) than systematically selected sites in Glacier Bay. Biomass estimates at Port Althorp were 5.2 and 9.7 at Idaho Inlet. Biomass estimates were dominated by species of Saxidomus, Protothaca and Mya in Glacier Bay and by Protothaca and Saxidomus at Idaho Inlet and Port Althrop. We suspect differences in density and biomass relate to habitat differences between areas within Glacier Bay

Annual report of the Marine Mammal Commission, calendar year 1992. Report to the Congress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-01-31

This is the 20th Annual Report of the Marine Mammal Commission and its Committee of Scientific Advisors on Marine Mammals. The Commission was established under Title II of the Marine Mammal Protection Act to provide an independent source of guidance on Federal activities and policies, both domestic and international, affecting marine mammal protection and conservation. Each year, the Marine Mammal Commission and its Committee of Scientific Advisors devote particular attention to marine mammal species or populations that are or may be in jeopardy. Chapter III describes efforts to conserve: sea otters in California and Alaska; Steller sea lions; Hawaiian monkmore » seals; harbor seals; northern fur seals; Pacific walruses; northern right whales; humpback whales; gray whales; bowhead whales; harbor porpoises; vaquitas or Gulf of California harbor porpoises; bottlenose dolphins; killer whales; and polar bears. Activities related to West Indian manatees, Hawaiian monk seals, vaquitas, and gray whales are summarized.« less

Winter marine bird and sea otter abundance of Prince William Sound, Alaska: Trends following the t/v Exxon Valdez oil spill from 1990-94. Restoration project 94159. Exxon Valdez oil spill restoration project final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agler, B.A.; Seiser, P.E.; Kendall, S.J.

1995-05-01

We conducted small boat surveys to determine population abundance of marine birds and sea otters (Enhydra lutris) in Prince William Sound, Alaska during March 1994. We observed 45 bird and 8 mammal species in Prince William Sound, and we estimated that 320,470 + or - 63,640 marine birds were present. We estimated trends in the March population estimates from 1990-94 by determining whether estimates in the oiled zone changed at the same rate as those in the unoiled zone. For Prince William Sound as a whole, we also examined the population trends from 1990-94 using regression analyses. We found significantmore » positive trends for harlequin duck (Histrionicus), goldeneye, merganser, bald eagle (Haliaeetus leucocephalus), black-legged kittiwake (Rissa tridactyla) and gull (Larus and Rissa spp.) populations. We also examined the relative abundance of marine bird species groups from 1972 to 1994. During March 1994, we estimated that the sea otter population was 7,746 + or - 2,073 otters. We found no difference in the rate of change between the oiled and unoiled zones from 1990-94, and there was no significant trend in the total number of sea otters in Prince William Sound from 1990-94.« less

Phocine Distemper Virus in Northern Sea Otters in the Pacific Ocean, Alaska, USA

PubMed Central

Mazet, Jonna A.K.; Gill, Verena A.; Doroff, Angela M.; Burek, Kathy A.; Hammond, John A.

2009-01-01

Phocine distemper virus (PDV) has caused 2 epidemics in harbor seals in the Atlantic Ocean but had never been identified in any Pacific Ocean species. We found that northern sea otters in Alaska are infected with PDV, which has created a disease threat to several sympatric and decreasing Pacific marine mammals. PMID:19523293

Mortality sensitivity in life-stage simulation analysis: A case study of southern sea otters

USGS Publications Warehouse

Gerber, L.R.; Tinker, M.T.; Doak, D.F.; Estes, J.A.; Jessup, David A.

2004-01-01

Currently, there are no generally recognized approaches for linking detailed mortality and pathology data to population-level analyses of extinction risk. We used a combination of analytical and simulation-based analyses to examine 20 years of age- and sex-specific mortality data for southern sea otters (Enhydra lutris), and we applied results to project the efficacy of alternative conservation strategies. Population recovery of the southern sea otter has been slow (rate of population increase ?? = 1.05) compared to other recovering populations (?? = 1.17-1.20), and the population declined (?? = 0.975) between 1995 and 1999. Age-based Leslie matrices were developed to explore explanations for the slow recovery and recent decline in the southern sea other population. An elasticity analysis was performed to predict effects of proportional changes in stage-specific reproductive or survival rates on the rate of population increase. A life-stage simulation analysis (LSA) was developed to evaluate the impact of changing age- and cause-specific mortality rates on ??. The information used to develop these models was derived from death assemblage, pathology, and live population census data to examine the sensitivity of sea otter population growth to different sources of mortality (e.g., disease and starvation, direct human take [fisheries, gun shot, boat strike, oil pollution], mating trauma and intraspecific aggression, shark bites, and unknown). We used resampling simulations to generate random combinations of vital rates for a large number of matrix replicates and drew on these to estimate potential effects of mortality sources on population growth (??). Our analyses suggest management actions that are likely and unlikely to promote recovery of the southern sea otter and more broadly indicate a methodology to better utilize cause-of-death data in conservation decision-making.

Causes and consequences of marine mammal population declines in southwest Alaska: a food-web perspective.

PubMed

Estes, J A; Doak, D F; Springer, A M; Williams, T M

2009-06-27

Populations of sea otters, seals and sea lions have collapsed across much of southwest Alaska over the past several decades. The sea otter decline set off a trophic cascade in which the coastal marine ecosystem underwent a phase shift from kelp forests to deforested sea urchin barrens. This interaction in turn affected the distribution, abundance and productivity of numerous other species. Ecological consequences of the pinniped declines are largely unknown. Increased predation by transient (marine mammal-eating) killer whales probably caused the sea otter declines and may have caused the pinniped declines as well. Springer et al. proposed that killer whales, which purportedly fed extensively on great whales, expanded their diets to include a higher percentage of sea otters and pinnipeds following a sharp reduction in great whale numbers from post World War II industrial whaling. Critics of this hypothesis claim that great whales are not now and probably never were an important nutritional resource for killer whales. We used demographic/energetic analyses to evaluate whether or not a predator-prey system involving killer whales and the smaller marine mammals would be sustainable without some nutritional contribution from the great whales. Our results indicate that while such a system is possible, it could only exist under a narrow range of extreme conditions and is therefore highly unlikely.

Potential for sea otter exposure to remnants of buried oil from the Exxon Valdez oil spill.

PubMed

Boehm, Paul D; Page, David S; Neff, Jerry M; Johnson, Charles B

2007-10-01

A study was conducted in 2005 and 2006 to examine the hypothesis that sea otters (Enhydra lutris) continue to be exposed to residues of subsurface oil (SSO) while foraging on shorelines in the northern Knight Island (NKI) area of Prince William Sound, Alaska more than 17 years after the Exxon Valdez oil spill. Forty-three shoreline segments, whose oiling history has been documented by prior surveys, were surveyed. These included all shoreline segments reported by a 2003 NOAA random site survey to contain SSO residues in NKI. Sites were surveyed for the presence and location of otter foraging pits. Only one of 29 SSO sites surveyed was identified as an otter foraging site. Most buried SSO residues are confined to tide elevations above +0.8 m above mean lower low water (MLLW), above the range of intertidal clam habitat. More than 99% of documented intertidal otter pits at all sites surveyed are in the lower intertidal zone (-0.2 to +0.8 m above MLLW), the zone of highest clam abundance. The spatial separation of the otter pits from the locations of SSO residues, both with regard to tidal elevation and lateral separation on the study sites, coupled with the lack of evidence of intertidal otter foraging at SSO sites indicates a low likelihood of exposure of foraging otters to SSO on the shores of the NKI area.

Reproduction, preweaning survival, and survival of adult sea otters at Kodiak Island, Alaska

USGS Publications Warehouse

Monson, Daniel H.; DeGange, Anthony R.

1995-01-01

Radiotelemetry methods were used to examine the demographic characteristics of sea otters inhabiting the leading edge of an expanding population on Kodiak Island, Alaska. Fifteen male and 30 female sea otters were instrumented and followed from 1986 to 1990. Twenty-one percent of females were sexually mature (had pupped) at age 2, 57% by age 3, 88% by age 4, and 100% by age 5. Fifteen females produced 26 pups, an overall reproduction rate of 94% for mature females. The reproduction rate was 17, 45, 66, and 100% for 2-, 3-, 4-, and 5-year-olds, respectively. Eighty-five percent of observed pups survived to weaning (120 days), and the percentage of pups weaned ranged from 34% for pups of 2-year-olds to 100% for pups of 5-year-olds. At least three of four known pup losses occurred within a month of parturition. The mean pup dependency period for weaned pups was 153 days and the mean gestation period was 218 days. No synchrony in pupping activity was observed. Mean annual survival of adults was high. Estimates of survival ranged from 89 to 96% for females and 86 to 91% for males. Human harvest was the primary source of known mortality of adults. Our estimates of reproductive rates and survival of adults are at the high end of those reported for sea otters, but preweaning survival stands out as being particularly high. Abundant food resources and the availability of protected water presumably contributed to the high reproductive success observed in this recently established sea otter population.

Differential gene expression induced by exposure of captive mink to fuel oil: A model for the sea otter

USGS Publications Warehouse

Bowen, Lizabeth; Riva, F.; Mohr, C.; Aldridge, B.; Schwartz, J.; Miles, A. Keith; Stott, J.L.

2007-01-01

Free-ranging sea otters are subject to hydrocarbon exposure from a variety of sources, both natural and anthropogenic. Effects of direct exposure to unrefined crude oil, such as that associated with the Exxon Valdez oil spill, are readily apparent. However, the impact of subtle but pathophysiologically relevant concentrations of crude oil on sea otters is difficult to assess. The present study was directed at developing a model for assessing the impact of low concentrations of fuel oil on sea otters. Quantitative PCR was used to identify differential gene expression in American mink that were exposed to low concentrations of bunker C fuel oil. A total of 23 genes, representing 10 different physiological systems, were analyzed for perturbation. Six genes with immunological relevance were differentially expressed in oil-fed mink. Interleukin-18 (IL-18), IL-10, inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and complement cytolysis inhibitor (CLI) were down-regulated while IL-2 was up-regulated. Expression of two additional genes was affected; heat shock protein 70 (HSP70) was up-regulated and thyroid hormone receptor (THR) was down-regulated. While the significance of each perturbation is not immediately evident, we identified differential expression of genes that would be consistent with the presence of immune system-modifying and endocrine-disrupting compounds in fuel oil. Application of this approach to identify effects of petroleum contamination on sea otters should be possible following expansion of this mink model to identify a greater number of affected genes in peripheral blood leukocytes.

Prolonged recovery of sea otters from the Exxon Valdez oil spill? A re-examination of the evidence.

PubMed

Garshelis, David L; Johnson, Charles B

2013-06-15

Sea otters (Enhydra lutris) suffered major mortality after the Exxon Valdez oil spill in Prince William Sound, Alaska, 1989. We evaluate the contention that their recovery spanned over two decades. A model based on the otter age-at-death distribution suggested a large, spill-related population sink, but this has never been found, and other model predictions failed to match empirical data. Studies focused on a previously-oiled area where otter numbers (~80) stagnated post-spill; nevertheless, post-spill abundance exceeded the most recent pre-spill count, and population trends paralleled an adjacent, unoiled-lightly-oiled area. Some investigators posited that otters suffered chronic effects by digging up buried oil residues while foraging, but an ecological risk assessment indicated that exposure levels via this pathway were well below thresholds for toxicological effects. Significant confounding factors, including killer whale predation, subsistence harvests, human disturbances, and environmental regime shifts made it impossible to judge recovery at such a small scale. Copyright © 2013 Elsevier Ltd. All rights reserved.

Verification of sex from harvested sea otters using DNA testing

USGS Publications Warehouse

Scribner, Kim T.; Green, Ben A.; Gorbics, Carol; Bodkin, James L.

2005-01-01

We used molecular genetic methods to determine the sex of 138 sea otters (Enhydra lutris) harvested from 3 regions of Alaska from 1994 to 1997, to assess the accuracy of post‐harvest field‐sexing. We also tested each of a series of factors associated with errors in field‐sexing of sea otters, including male or female bias, age‐class bias, regional bias, and bias associated with hunt characteristics. Blind control results indicated that sex was determined with 100% accuracy using polymerase chain reaction (PCR) amplification using primers that co‐amplify the zinc finger‐Y‐X gene, located on both the mammalian Y‐ and X‐chromosomes, and Testes Determining Factor (TDF), located on the mammalian Y‐chromosome. DNA‐based sexing revealed that 12.3% of the harvested sea otters were incorrectly sexed in the field, with most errors (13 of 17) occurring as males incorrectly reported as females. Thus, female harvest was overestimated. Using logistic regression analysis, we detected no statistical association of incorrect determination of sex in the field with age class, hunt region, or hunt type. The error in field‐sexing appears to be random, at least with respect to the variables evaluated in this study.

Killer whales and marine mammal trends in the North Pacific - A re-examination of evidence for sequential megafauna collapse and the prey-switching hypothesis

USGS Publications Warehouse

Wade, P.R.; Burkanov, V.N.; Dahlheim, M.E.; Friday, N.A.; Fritz, L.W.; Loughlin, Thomas R.; Mizroch, S.A.; Muto, M.M.; Rice, D.W.; Barrett-Lennard, L. G.; Black, N.A.; Burdin, A.M.; Calambokidis, J.; Cerchio, S.; Ford, J.K.B.; Jacobsen, J.K.; Matkin, C.O.; Matkin, D.R.; Mehta, A.V.; Small, R.J.; Straley, J.M.; McCluskey, S.M.; VanBlaricom, G.R.; Clapham, P.J.

2007-01-01

Springer et al. (2003) contend that sequential declines occurred in North Pacific populations of harbor and fur seals, Steller sea lions, and sea otters. They hypothesize that these were due to increased predation by killer whales, when industrial whaling's removal of large whales as a supposed primary food source precipitated a prey switch. Using a regional approach, we reexamined whale catch data, killer whale predation observations, and the current biomass and trends of potential prey, and found little support for the prey-switching hypothesis. Large whale biomass in the Bering Sea did not decline as much as suggested by Springer et al., and much of the reduction occurred 50-100 yr ago, well before the declines of pinnipeds and sea otters began; thus, the need to switch prey starting in the 1970s is doubtful. With the sole exception that the sea otter decline followed the decline of pinnipeds, the reported declines were not in fact sequential. Given this, it is unlikely that a sequential megafaunal collapse from whales to sea otters occurred. The spatial and temporal patterns of pinniped and sea otter population trends are more complex than Springer et al. suggest, and are often inconsistent with their hypothesis. Populations remained stable or increased in many areas, despite extensive historical whaling and high killer whale abundance. Furthermore, observed killer whale predation has largely involved pinnipeds and small cetaceans; there is little evidence that large whales were ever a major prey item in high latitudes. Small cetaceans (ignored by Springer et al.) were likely abundant throughout the period. Overall, we suggest that the Springer et al. hypothesis represents a misleading and simplistic view of events and trophic relationships within this complex marine ecosystem. ?? 2007 by the Society for Marine Mammalogy.

Synthesis of nearshore recovery following the 1989 Exxon Valdez oil spill: sea otter liver pathology and survival in Western Prince William Sound, 2001 – 2008

USGS Publications Warehouse

Ballachey, Brenda E.; Monson, Daniel H.; Kloecker, Kimberly A.; Esslinger, George G.; Mohr, F.C.; Lipscomb, T.P.; Murray, M.J.; Howlin, S.

2014-01-01

We examined livers and liver biopsies collected from captured sea otters in WPWS, 2001–2008, to determine whether indicators of liver health correlated with history of oil contamination from the 1989 Exxon Valdez oil spill. Sea otters captured in oiled areas had a significantly higher proportion of livers with gross pathological change, based on visual inspection at the time of capture, than those from unoiled areas. Of the 10 histopathology variables scored on liver biopsies, only two (vacuolar change and pigment) differed between animals from oiled and unoiled areas, and neither correlated with gross pathology scores. Vacuolar change indicates physiological disturbance, which is consistent with potential effects from oil exposure but also could be influenced by a number of other factors. We concluded that, as of 2008, some differences in liver health were evident between sea otters from oiled and unoiled areas; these differences were consistent with, but not specific to, effects that might be expected with sublethal exposure to lingering Exxon Valdez oil. We also quantified variation in survival of radiomarked sea otters within oiled areas of WPWS in relation to age, sex, body condition, selected blood serum chemistry variables, and histological scores indicative of liver health. Of the variables considered, only the serum enzyme aspartate aminotransferase (AST) and the ratio of serum proteins albumin and globulin (A/G) were correlated with survival, with higher levels of AST and lower levels of A/G associated with increased likelihood of mortality. High AST and low A/G both may be indicative of liver disease. Taken together, results reported here suggest that liver health of sea otters in oiled areas was slightly poorer than those from unoiled areas and, ifurther, that this may have translated to poorer survival through 2008, nearly 2 decades after the spill. More recently collected information indicated that mortality patterns and abundance had returned to pre-spill conditions between 2010 and 2013, suggesting that the effects that we detected through 2008 may have represented the end of effects related to exposure to lingering oil.

Airborne Mission Concept for Coastal Ocean Color and Ecosystems Research

NASA Technical Reports Server (NTRS)

Guild, Liane S.; Hooker, Stanford B.; Morrow, John H.; Kudela, Raphael M.; Palacios, Sherry L.; Torres Perez, Juan L.; Hayashi, Kendra; Dunagan, Stephen E.

2016-01-01

NASA airborne missions in 2011 and 2013 over Monterey Bay, CA, demonstrated novel above- and in-water calibration and validation measurements supporting a combined airborne sensor approach (imaging spectrometer, microradiometers, and a sun photometer). The resultant airborne data characterize contemporaneous coastal atmospheric and aquatic properties plus sea-truth observations from state-of-the-art instrument systems spanning a next-generation spectral domain (320-875 nm). This airborne instrument suite for calibration, validation, and research flew at the lowest safe altitude (ca. 100 ft or 30 m) as well as higher altitudes (e.g., 6,000 ft or 1,800 m) above the sea surface covering a larger area in a single synoptic sortie than ship-based measurements at a few stations during the same sampling period. Data collection of coincident atmospheric and aquatic properties near the sea surface and at altitude allows the input of relevant variables into atmospheric correction schemes to improve the output of corrected imaging spectrometer data. Specific channels support legacy and next-generation satellite capabilities, and flights are planned to within 30 min of satellite overpass. This concept supports calibration and validation activities of ocean color phenomena (e.g., river plumes, algal blooms) and studies of water quality and coastal ecosystems. The 2011 COAST mission flew at 100 and 6,000 ft on a Twin Otter platform with flight plans accommodating the competing requirements of the sensor suite, which included the Coastal-Airborne In-situ Radiometers (C-AIR) for the first time. C-AIR (Biospherical Instruments Inc.) also flew in the 2013 OCEANIA mission at 100 and 1,000 ft on the Twin Otter below the California airborne simulation of the proposed NASA HyspIRI satellite system comprised of an imaging spectrometer and thermal infrared multispectral imager on the ER-2 at 65,000 ft (20,000 m). For both missions, the Compact-Optical Profiling System (Biospherical Instruments, Inc.), an in-water system with microradiometers matching C-AIR, was deployed to compare sea-truth measurements and low-altitude Twin Otter flights within Monterey Bay red tide events. This novel airborne and in-water sensor capability advances the science of coastal measurements and enables rapid response for coastal events.

Trends in sea otter population abundance in western Prince William Sound, Alaska: Progress toward recovery following the 1989 Exxon Valdez oil spill

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.; Esslinger, George G.

2011-01-01

Sea otters in western Prince William Sound (WPWS) and elsewhere in the Gulf of Alaska suffered widespread mortality as a result of oiling following the 1989 T/V Exxon Valdez oil spill. Following the spill, extensive efforts have been directed toward identifying and understanding long-term consequences of the spill and the process of recovery. We conducted annual aerial surveys of sea otter abundance from 1993 to 2009 (except for 2001 and 2006) in WPWS. We observed an increasing trend in population abundance at the scale of WPWS through 2000 at an average annual rate of 4 percent: however, at northern Knight Island where oiling was heaviest and sea otter mortality highest, no increase in abundance was evident by 2000. We continued to see significant increase in abundance at the scale of WPWS between 2001 and 2009, with an average annual rate of increase from 1993 to 2009 of 2.6 percent. We estimated the 2009 population size of WPWS to be 3,958 animals (standard error=653), nearly 2,000 animals more than the first post-spill estimate in 1993. Surveys since 2003 also have identified a significant increasing trend at the heavily oiled site in northern Knight Island, averaging about 25 percent annually and resulting in a 2009 estimated population size of 116 animals (standard error=19). Although the 2009 estimate for northern Knight Island remains about 30 percent less than the pre-spill estimate of 165 animals, we interpret this trend as strong evidence of a trajectory toward recovery of spill-affected sea otter populations in WPWS.

Foraging ecology

USGS Publications Warehouse

Tinker, M. Tim; Estes, James A.; Staedler, Michelle; Bodkin, James L.; Tinker, M. Tim; Estes, James A.; Ralls, Katherine; Williams, Terrie M.; Jessup, David A.; Costa, Daniel P.

2006-01-01

Longitudinal foraging data collected from 60 sea otters implanted with VHF radio transmitters at two study sites in Central California over a three-year period demonstrated even greater individual dietary specialization than in previous studies, with only 54% dietary overlap between individuals and the population.Multivariate statistical analyses indicated that individual diets could be grouped into three general "diet types" representing distinct foraging specializations. Type 1 specialists consumed large size prey but had low dive efficiency, Type 2 specialists consumed small to medium size prey with high dive efficiency, and Type 3 specialists consumed very small prey (mainly snails) with very high dive efficiency.The mean rate of energy gain for the population as a whole was low when compared to other sea otter populations in Alaska but showed a high degree of within- and betweenindividual variation, much of which was accounted for by the three foraging strategies. Type 1 specialists had the highest mean energy gain but also the highest withinindividual variance in energy gain. Type 2 specialists had the lowest mean energy gain but also the lowest variance. Type 3 specialists had an intermediate mean and variance. All three strategies resulted in very similar probabilities of exceeding a critical rate of energy gain on any given day.Correlational selection may help maintain multiple foraging strategies in the population: a fitness surface (using mean rate of energy gain as a proxy for fitness) fit to the first two principal components of foraging behavior suggested that the three foraging strategies occupy separate fitness peaks.Food limitation is likely an important ultimate factor restricting population growth in the center of the population’s range in California, although the existence of alternative foraging strategies results in different impacts of food limitation on individuals and thus may obscure expected patterns of density dependence.

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeGange, A.R.; Douglas, D.C.; Monson, D.H.

Sea otter (Enhydra lutris) abundance and distribution in the Gulf of Alaska west of Prince William Sound were surveyed by helicopter in the spring of 1989 at the time of the Exxon Valdez oil spill and the following fall. Estimated population sizes did not significantly decline between spring and fall for areas with comparable survey data. No significant (p>0.05) shifts of sea otter distributions in heavily, lightly and unoiled areas were detected between spring and fall surveys.

Complex trophic interactions in kelp forest ecosystems

USGS Publications Warehouse

Estes, J.A.; Danner, E.M.; Doak, D.F.; Konar, B.; Springer, A.M.; Steinberg, P.D.; Tinker, M. Tim; Williams, T.M.

2004-01-01

The distributions and abundances of species and populations change almost continuously. Understanding the processes responsible is perhaps ecology’s most fundamental challenge. Kelp-forest ecosystems in southwest Alaska have undergone several phase shifts between alga- and herbivore-dominated states in recent decades. Overhunting and recovery of sea otters caused the earlier shifts. Studies focusing on these changes demonstrate the importance of top-down forcing processes, a variety of indirect food-web interactions associated with the otter-urchin-kelp trophic cascade, and the role of food-chain length in the coevolution of defense and resistance in plants and their herbivores. This system unexpectedly shifted back to an herbivore-dominated state during the 1990s, because of a sea-otter population collapse that apparently was driven by increased predation by killer whales. Reasons for this change remain uncertain but seem to be linked to the whole-sale collapse of marine mammals in the North Pacific Ocean and southern Bering Sea. We hypothesize that killer whales sequentially "fished down" pinniped and sea-otter populations after their earlier prey, the great whales, were decimated by commercial whaling. The dynamics of kelp forests in southwest Alaska thus appears to have been influenced by an ecological chain reaction that encompassed numerous species and large scales of space and time.

Studying sea otter foraging ecology: A review of some methodological approaches

USGS Publications Warehouse

Tinker, M.T.; Estes, J.A.; Bodkin, James L.; Staedler, M.M.; Monson, Daniel H.; Maldini, Daniela; Calkins, Donald; Atkinson, Shannon; Meehan, Rosa

2004-01-01

The study of foraging ecology plays a central role in our understanding of animal populations and natural communities, and can also provide information necessary for the effective conservation of rare or endangered species. Sea otter researchers are interested in foraging ecology for many different reasons, but for heuristic purposes we identify three general types of research questions: (1) questions about the implications of foraging decisions to individual fitness, the evolutionary significance of feeding strategies, and the selective forces and constraints that shape an individual’s diet and feeding behavior; (2) questions about the population- level implications of foraging ecology; for example, how is the status of a population (with respect to carrying capacity) reflected by the foraging success or diet composition of individuals within the population (Fig. 1); and (3) questions about the community-level consequences of sea otter foraging. Sea otters provide an excellent study system for all three types of questions because they are a tractable species to study (generally feeding near shore and bringing all prey to the surface to consume), they exhibit a wide range of diets and foraging strategies in different habitats and at different population densities, they tend to have strong trophic interactions with their prey species, and their foraging behavior can have profound effects on community structure in the nearshore marine community.

Asynchrony in craniomandibular development and growth in Enhydra lutris nereis (Carnivora: Mustelidae): Are southern sea otters born to bite?

USGS Publications Warehouse

Law, Chris J; Baliga, Vikram B.; Tinker, M. Tim; Mehta, Rita S.

2017-01-01

Weaning represents a major ontogenetic dietary shift in southern sea otters (Enhydra lutris nereis), as juveniles must transition from depending on mother’s milk to independently processing hard-shelled invertebrates. When the skulls of juveniles have reached sufficient maturity to transition to a durophagous diet remains to be investigated. Here, we conducted a comprehensive analysis of skull development and growth and sexual dimorphism using geometric morphometric approaches in 204 southern sea otter skulls. We found that southern sea otters of both sexes exhibit dramatic changes in cranial and mandibular shape and size over ontogeny. Although the majority of these changes occur in the pup stage, full development and growth of the skull does not occur until well after weaning. We hypothesize that the slower maturation of the crania of newly weaned juveniles serves as a handicap by constraining jaw adductor muscle size, biting ability and feeding on hard-shelled prey. In our analysis of sexual dimorphism, we found significant sexual shape and size dimorphism in adult craniomandibular morphology that arose through differences in developmental and growth rates and duration. We postulate that males are selected to attain mature crania faster to presumably reach adult biting ability sooner, gaining a competitive advantage in obtaining food and in male–male agonistic interactions.

Stock structure of sea otters (Enhydra lutris kenyoni) in Alaska

USGS Publications Warehouse

Gorbics, C.S.; Bodkin, James L.

2001-01-01

Sea otters in Alaska are recognized as a single subspecies (Enhydra lutris kenyoni) and currently managed as a single, interbreeding population. However, geographic and behavioral mechanisms undoubtably constrain sea otter movements on much smaller scales. This paper applies the phylogeographic method (Dizon et al. 1992) and considers distribution, population response, phenotype and genotype data to identify stocks of sea otters within Alaska. The evidence for separate stock identity is genotypic (all stocks), phenotypic (Southcentral and Southwest stocks), and geographic distribution (Southeast stock), whereas population response data are equivocal (all stocks). Differences in genotype frequencies and the presence of unique genotypes among areas indicate restricted gene flow. Genetic exchange may be limited by little or no movement across proposed stock boundaries and discontinuities in distribution at proposed stock boundaries. Skull size differences (phenotypic) between Southwest and Southcentral Alaska populations further support stock separation. Population response information was equivocal in either supporting or refuting stock identity. On the basis of this review, we suggest the following: (1) a Southeast stock extending from Dixon Entrance to Cape Yakataga; (2) a Southcentral stock extending from Cape Yakataga to Cape Douglas including Prince William Sound and Kenai peninsula coast; and (3) a Southwest stock including Alaska Peninsula coast, the Aleutians to Attu Island, Barren, Kodiak, Pribilof Islands, and Bristol Bay.

An aerial survey method to estimate sea otter abundance

USGS Publications Warehouse

Bodkin, James L.; Udevitz, Mark S.; Garner, Gerald W.; Amstrup, Steven C.; Laake, Jeffrey L.; Manly, Bryan F.J.; McDonald, Lyman L.; Robertson, Donna G.

1999-01-01

Sea otters (Enhydra lutris) occur in shallow coastal habitats and can be highly visible on the sea surface. They generally rest in groups and their detection depends on factors that include sea conditions, viewing platform, observer technique and skill, distance, habitat and group size. While visible on the surface, they are difficult to see while diving and may dive in response to an approaching survey platform. We developed and tested an aerial survey method that uses intensive searches within portions of strip transects to adjust for availability and sightability biases. Correction factors are estimated independently for each survey and observer. In tests of our method using shore-based observers, we estimated detection probabilities of 0.52-0.72 in standard strip-transects and 0.96 in intensive searches. We used the survey method in Prince William Sound, Alaska to estimate a sea otter population size of 9,092 (SE = 1422). The new method represents an improvement over various aspects of previous methods, but additional development and testing will be required prior to its broad application.

Wave disturbance overwhelms top-down and bottom-up control of primary production in California kelp forests.

PubMed

Reed, Daniel C; Rassweiler, Andrew; Carr, Mark H; Cavanaugh, Kyle C; Malone, Daniel P; Siegel, David A

2011-11-01

We took advantage of regional differences in environmental forcing and consumer abundance to examine the relative importance of nutrient availability (bottom-up), grazing pressure (top-down), and storm waves (disturbance) in determining the standing biomass and net primary production (NPP) of the giant kelp Macrocystis pyrifera in central and southern California. Using a nine-year data set collected from 17 sites we show that, despite high densities of sea urchin grazers and prolonged periods of low nutrient availability in southern California, NPP by giant kelp was twice that of central California where nutrient concentrations were consistently high and sea urchins were nearly absent due to predation by sea otters. Waves associated with winter storms were consistently higher in central California, and the loss of kelp biomass to winter wave disturbance was on average twice that of southern California. These observations suggest that the more intense wave disturbance in central California limited NPP by giant kelp under otherwise favorable conditions. Regional patterns of interannual variation in NPP were similar to those of wave disturbance in that year-to-year variation in disturbance and NPP were both greater in southern California. Our findings provide strong evidence that regional differences in wave disturbance overwhelmed those of nutrient supply and grazing intensity to determine NPP by giant kelp. The important role of disturbance in controlling NPP revealed by our study is likely not unique to giant kelp forests, as vegetation dynamics in many systems are dominated by post-disturbance succession with climax communities being relatively uncommon. The effects of disturbance frequency may be easier to detect in giant kelp because it is fast growing and relatively short lived, with cycles of disturbance and recovery occurring on time scales of years. Much longer data sets (decades to centuries) will likely be needed to properly evaluate the role of disturbance relative to other processes in determining patterns of NPP in other systems.

Life history plasticity and population regulation in sea otters

USGS Publications Warehouse

Monson, Daniel H.; Estes, James A.; Bodkin, James L.; Siniff, Donald B.

2000-01-01

We contrasted body condition, and age-specific reproduction and mortality between a growing population of sea otters (Enhydralutris) at Kodiak Island and a high-density near-equilibrium population at Amchitka Island, Alaska. We obtained data from marked individuals, population surveys, and collections of beach-cast carcasses. Mass:length ratios indicated that females (but not males) captured in 1992 at Amchitka were in poorer condition than those captured at Kodiak in 1986–1987. In 1993, the condition of females at Amchitka improved in apparent response to two factors: (1) an episodic influx of Pacific smooth lumpsuckers, Aptocyclus ventricocus, from the epi-pelagic zone, which otters consumed; and (2) an increase in the otters’ benthic invertebrate prey resulting from declining otter numbers. Reproductive rates varied with age (0.37 [CI=0.21 to 0.53] births female−1 yr−1 for 2–3-yr-olds, and 0.83 [CI=0.69 to 0.90] for females ≥4 yr old), and were similar at both areas. Weaning success (pups surviving to ≥120 d), in contrast, was almost 50% lower at Amchitka than at Kodiak and for females ≥4 yr of age was 0.52 (CI=0.38 to 0.66) vs 0.94 (CI=0.75 to 0.99), respectively. Sixty-two percent of the preweaning pup losses at Amchitka occurred within a month of parturition and 79% within two months. Postweaning survival was also low at Amchitka as only 18% of instrumented pups were known to be alive one year after mother-pup separation. Adult survival rates appeared similar at Amchitka and Kodiak. Factors affecting survival early in life thus are a primary demographic mechanism of population regulation in sea otters. By maintaining uniformly high reproductive rates over time and limiting investment in any particular reproductive event, sea otters can take advantage of unpredictable environmental changes favorable to pup survival. This strategy is consistent with predictions of “bet-hedging” life history models.

Cruise Report for the April 2009 Gulf of Alaska Line- Transect Survey (GOALS) in the Navy Training Exercise Area

DTIC Science & Technology

2009-06-01

Whidbey Island on 26 March; however, due to the eruption of the Redoubt volcano , the flight was suspended. The second flight was scheduled to fly in on...GOALS 2009 research cruise (green = fin whales, red = gray whales, orange = humpback whales, yellow = minke whales; open circles = on-effort...otter sightings during GOALS 2009 research cruise (black = Steller sea lion, green = sea otter, yellow = harbor seal, red = unidentified pinniped

Stress-related hormones and genetic diversity in sea otters (Enhydra lutris)

USGS Publications Warehouse

Larson, Shawn E.; Monson, Daniel H.; Ballachey, Brenda E.; Jameson, Ronald J.; Wasser, S.K.

2009-01-01

Sea otters (Enhydra lutris) once ranged throughout the coastal regions of the north Pacific, but were extirpated throughout their range during the fur trade of the 18th and 19th centuries, leaving only small, widely scattered, remnant populations. All extant sea otter populations are believed to have experienced a population bottleneck and thus have lost genetic variation. Populations that undergo severe population reduction and associated inbreeding may suffer from a general reduction in fitness termed inbreeding depression. Inbreeding depression may result in decreased testosterone levels in males, and reduced ability to respond to stressful stimuli associated with an increase in the stress-related adrenal glucocorticoid hormones, cortisol and corticosterone. We investigated correlations of testosterone, cortisol, and corticosterone with genetic diversity in sea otters from five populations. We found a significant negative correlation between genetic diversity and both mean population-level (r2= 0.27, P < 0.001) and individual-level (r2= 0.54, P < 0.001) corticosterone values, as well as a negative correlation between genetic diversity and cortisol at the individual level (r2= 0.17, P= 0.04). No relationship was found between genetic diversity and testosterone (P= 0.57). The strength of the correlations, especially with corticosterone, suggests potential negative consequences for overall population health, particularly for populations with the lowest genetic diversity.

Structure and mechanism of diet specialisation: testing models of individual variation in resource use with sea otters

USGS Publications Warehouse

Tinker, M. Tim; Guimarães, Paulo R.; Novak, Mark; Marquitti, Flavia Maria Darcie; Bodkin, James L.; Staedler, Michelle; Bentall, Gena B.; Estes, James A.

2012-01-01

Studies of consumer-resource interactions suggest that individual diet specialisation is empirically widespread and theoretically important to the organisation and dynamics of populations and communities. We used weighted networks to analyze the resource use by sea otters, testing three alternative models for how individual diet specialisation may arise. As expected, individual specialisation was absent when otter density was low, but increased at high-otter density. A high-density emergence of nested resource-use networks was consistent with the model assuming individuals share preference ranks. However, a density-dependent emergence of a non-nested modular network for ‘core’ resources was more consistent with the ‘competitive refuge’ model. Individuals from different diet modules showed predictable variation in rank-order prey preferences and handling times of core resources, further supporting the competitive refuge model. Our findings support a hierarchical organisation of diet specialisation and suggest individual use of core and marginal resources may be driven by different selective pressures.

California State Waters map series—Offshore of Scott Creek, California

USGS Publications Warehouse

Cochrane, Guy R.; Dartnell, Peter; Johnson, Samuel Y.; Greene, H. Gary; Erdey, Mercedes D.; Dieter, Bryan E.; Golden, Nadine E.; Endris, Charles A.; Hartwell, Stephen R.; Kvitek, Rikk G.; Davenport, Clifton W.; Watt, Janet T.; Krigsman, Lisa M.; Ritchie, Andrew C.; Sliter, Ray W.; Finlayson, David P.; Maier, Katherine L.; Cochrane, Guy R.; Cochran, Susan A.

2015-11-16

Seafloor habitats in the Offshore of Scott Creek map area, which lie within the Shelf (continental shelf) megahabitat, range from significant rocky outcrops that support kelp-forest communities nearshore to rocky-reef communities in deeper water. Biological productivity resulting from coastal upwelling supports populations of Sooty Shearwater, Western Gull, Common Murre, Cassin’s Auklet, and many other less populous bird species. In addition, an observable recovery of Humpback and Blue Whales has occurred in the area; both species are dependent on coastal upwelling to provide nutrients. The large extent of exposed inner shelf bedrock supports large forests of “bull kelp,” which is well adapted for high-wave-energy environments. The kelp beds are the northernmost known habitat for the population of southern sea otters. Common fish species found in the kelp beds and rocky reefs include lingcod and various species of rockfish and greenling.

An otter tragedy. [Environmental effects of oil spills

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raloff, J.

1993-03-27

Otters appear to be the most vulnerable of all marine mammals to oil; oil reduces the insulating value of their fur by as much as 70% and otters are extremely vulnerable to oil poisoning through inhalation of hydrocarbon fumes, ingestion of petroleum, and absorption through the skin. After the Exxon Valdez accident in Alaska's Prince William Sound, dramatic efforts were made to rescue and rehabilitate otters and other sea animals. One hundred ninety seven of the treated otters were released back into the wild. However, soon after the release, wildlife biologist Lisa Rotterman reported an unprecidented die-off of never-oiled otters.more » Many of the treated otters may have carried a potentially novel herpesvirus, but whether this caused the die-off is controversial. It is also hard to separate symptoms of sickness, stress, and fear from oil toxicity. Overall the findings suggest a generic regimen for all oiled otters: antibiotics, vitamin and mineral supplements, and prompt administration of fluids. Assessing which animals need care is an urgent need. Strict quarantine, short captivity time, and protected handling of oiled animals are further suggestions.« less

Amnesic Shellfish Poisoning

MedlinePlus

... the U.S. west coast in spring 1991, when sea lions and sea birds were sickened after eating toxin-laden anchovies. ... crab is another way that animals such as sea otters can become sickened or die due to ...

Analysis of the sea otter (Enhydra lutris) reproductive tract: A methods manual

USGS Publications Warehouse

von Biela, Vanessa R.; Gill, Verena A.

2007-01-01

Sea otter reproductive tracts have most commonly come from either intentional sampling through harvests (Sinah et al. 1966, Schneider 1975) or unintentional large scale mortalities (e.g. the 1989 Exxon Valdez oil spill) (Bodkin et al. 1993). Carcasses and reproductive tracts can also be obtained through the collection of fresh beach cast carcasses. Analysis of reproductive tracts should consider the source of carcasses as samples representing either the “living” or “dead” sea otter population, as they may differ in reproductive parameters. In most cases the reproductive tracts are fixed in formalin or frozen (minimum of –20˚C) immediately after collection; both methods are acceptable for later analysis of the tissue. Immediate fixation is preferred as it is a necessary step in analysis. Uteri and ovaries are then examined to determine the current and past reproductive history of each individual. This manual also includes an example datasheet (Appendix A) and glossary (Appendix B). 

Phenotypic plasticity in age at first reproduction of female northern sea otters (Enhydra lutris kenyoni)

USGS Publications Warehouse

Von Biela, V.R.; Gill, V.A.; Bodkin, James L.; Burns, Jennifer M.

2009-01-01

Life-history theory predicts that within a species, reproduction and survival rates will differ among populations that differ in resource availability or predation rates through phenotypic plasticity. When populations are near carrying capacity (K) or when they are declining due to reduced prey resources, the average age at 1st reproduction (average AFR) is predicted to be older than in populations below K. Differences between the trajectories of northern sea otter (Enhydra lutris kenyoni) populations in Alaska provides an opportunity to examine phenotypic plasticity. Using premolar teeth or reproductive tracts, we estimated average AFR from demographically distinct populations of sea otters in Alaska. We obtained samples from 2 populations near K, Prince William Sound (PWS) and the Aleutian Archipelago (archived samples), and from 2populations below K, the Kodiak Archipelago and Sitka. The average AFR was lower in populations below K (3.60 years ??0.16 SD)compared to those near K (4.21 ?? 0.13 years, P <0.001), and differed among all populations, with the Aleutian population possessing the oldest average AFR (4.29 ?? 0.09 years) followed by PWS (4.05 ?? 0.24 years), Sitka (3.80 ?? 0.21 years), and Kodiak (3.19 ?? 0.37 years). The difference in average AFR among populations supports life-history theory and provides evidence of phenotypic plasticity in sea otters. Our findings highlight the value of using average AFR as a tool for monitoring mammalian populations. ?? 2009 American Society of Mammalogists.

Foraging patterns and prey selection in an increasing and expanding sea otter population

USGS Publications Warehouse

Laidre, K.L.; Jameson, R.J.

2006-01-01

Focal observations of sea otter (Enhydra lutris kenyoni) foraging patterns and prey selection were collected in coastal Washington between 1993 and 1999. Records consisted of 13,847 individual dives from 841 feeding bouts ranging from 1 min to >4 h. Average dive time was 55 s ?? 0.9 SE and average surface time was 45 s ?? 2.3 SE, irrespective of dive success. At least 77% of all dives (n = 10,636) were successful prey captures (dives in low light or of undetermined success were excluded). Prey capture success was significantly lower for subadults (63% ?? 5 SE) than adults (82% ?? 1 SE; P 60% red urchins (Strongylocentrotus franciscanus), with only 2 other prey species comprising >10% of their diet. Prey size and prey category were dominant predictor variables in generalized linear models of dive duration and postdive surface duration on successful dives. Significant increases in areal extent of surface canopy of giant kelp (Macrocystis integrifolia) and bull kelp (Nereocystis leutkeana) were found both in the outer coast and the Strait of Juan de Fuca (0.4-0.5 km2 per year, P < 0.05) and suggest increasing suitable habitat for a growing population. The growth and expansion of a small and isolated sea otter population provides a unique opportunity to examine the relationship between dietary diversity and population status and explore similarities and differences between trophic paradigms established for sea otter populations at other localities. ?? 2006 American Society of Mammalogists.

Marine bird and sea otter population abundance of Prince william sound, Alaska: Trends following the t/v Exxon Valdez oil spill, 1989-93. Restoration project 93045. Exxon Valdez oil spill restoration project final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agler, B.A.; Seiser, P.E.; Kendall, S.J.

1994-05-01

We conducted small boat surveys to estimate marine bird and sea otter (Enhdra lutris) populations in Prince William Sound, Alaska during March and July 1993, using methods developed for the 1989-91 surveys (Klosiewski and Laing 1994). During 1993, we recorded 65 birds and 13 mammal species. We estimated that 402,760 + or - 167,697 marine birds were in the Sound during March 1993, an increase of >200,000 birds over 1990 and 1991. To examine trends in our marine bird population estimates from 1989-93, we assumed that in the absence of oil spill effects, population estimates in the oiled zone wouldmore » change at the same rate as those in the unoiled zone. For Prince William Sound as a whole, we examined population trends from 1989-1993, using regression analyses. We also examined the relative abundance of the species groups seen in Prince William Sound from 1972 to 1993. Sea otter populations in 1993 were estimated at 6,813 + or - 1,861 for March and 8,216 + or - 2,435 for July. We found no difference in the rate of change between the oiled and unoiled zones from 1989-93 for either the March or July population estimates. There was no significant trend in the total number of sea otters in Prince William Sound from 1989-93.« less

Sea otters, kelp forests, and the extinction of Steller's sea cow.

PubMed

Estes, James A; Burdin, Alexander; Doak, Daniel F

2016-01-26

The late Pleistocene extinction of so many large-bodied vertebrates has been variously attributed to two general causes: rapid climate change and the effects of humans as they spread from the Old World to previously uninhabited continents and islands. Many large-bodied vertebrates, especially large apex predators, maintain their associated ecosystems through top-down forcing processes, especially trophic cascades, and megaherbivores also exert an array of strong indirect effects on their communities. Thus, a third possibility for at least some of the Pleistocene extinctions is that they occurred through habitat changes resulting from the loss of these other keystone species. Here we explore the plausibility of this mechanism, using information on sea otters, kelp forests, and the recent extinction of Steller's sea cows from the Commander Islands. Large numbers of sea cows occurred in the Commander Islands at the time of their discovery by Europeans in 1741. Although extinction of these last remaining sea cows during early years of the Pacific maritime fur trade is widely thought to be a consequence of direct human overkill, we show that it is also a probable consequence of the loss of sea otters and the co-occurring loss of kelp, even if not a single sea cow had been killed directly by humans. This example supports the hypothesis that the directly caused extinctions of a few large vertebrates in the late Pleistocene may have resulted in the coextinction of numerous other species.

Sea otters, kelp forests, and the extinction of Steller’s sea cow

PubMed Central

Estes, James A.; Burdin, Alexander; Doak, Daniel F.

2016-01-01

The late Pleistocene extinction of so many large-bodied vertebrates has been variously attributed to two general causes: rapid climate change and the effects of humans as they spread from the Old World to previously uninhabited continents and islands. Many large-bodied vertebrates, especially large apex predators, maintain their associated ecosystems through top-down forcing processes, especially trophic cascades, and megaherbivores also exert an array of strong indirect effects on their communities. Thus, a third possibility for at least some of the Pleistocene extinctions is that they occurred through habitat changes resulting from the loss of these other keystone species. Here we explore the plausibility of this mechanism, using information on sea otters, kelp forests, and the recent extinction of Steller's sea cows from the Commander Islands. Large numbers of sea cows occurred in the Commander Islands at the time of their discovery by Europeans in 1741. Although extinction of these last remaining sea cows during early years of the Pacific maritime fur trade is widely thought to be a consequence of direct human overkill, we show that it is also a probable consequence of the loss of sea otters and the co-occurring loss of kelp, even if not a single sea cow had been killed directly by humans. This example supports the hypothesis that the directly caused extinctions of a few large vertebrates in the late Pleistocene may have resulted in the coextinction of numerous other species. PMID:26504217

Wolfhounds and Polar Bears in Siberia: America’s Military Intervention, 1918-1920

DTIC Science & Technology

1986-01-01

including sable, sea otter, otter, beaver, mink, muskrat, squirrel, fox, skunk, woodchuck, marmot , badger, glutton, and rabbit. Vast forests provided wood for...venti- lated, heated, and lighted. A kitchen was found on the end of each floor in the barracks. Latrines drained into open cesspools. Wood burning

Biological characterisation of Sarcocystis neurona isolated from a Southern sea otter (Enhydra lutris nereis)

USGS Publications Warehouse

Lindsay, D.S.; Thomas, N.J.; Dubey, J.P.

2000-01-01

Sarcocystis neurona was isolated from the brain of a juvenile, male southern sea otter (Enhydra lutris nereis) suffering from CNS disease. Schizonts and merozoites in tissue sections of the otter's brain reacted with anti-S. neurona antiserum immunohistochemically. Development in cell culture was by endopolyogeny and mature schizonts were first observed at 3 days postinoculation. PCR of merozoite DNA using primer pairs JNB33/JNB54 and restriction enzyme digestion of the 1100 bp product with Dra I indicated the organism was S. neurona. Four of four interferon-γ gene knockout mice inoculated with merozoites developed S. neurona-associated encephalitis. Antibodies to S. neurona but not Sarcocystis falcatula, Toxoplasma gondii, or Neospora caninum were present in the serum of inoculated mice. This is the first isolation of S. neurona from the brain of a non-equine host.

Interactions of marine mammals and birds with offshore membrane enclosures for growing algae (OMEGA).

PubMed

Hughes, Stephanie N; Tozzi, Sasha; Harris, Linden; Harmsen, Shawn; Young, Colleen; Rask, Jon; Toy-Choutka, Sharon; Clark, Kit; Cruickshank, Marilyn; Fennie, Hamilton; Kuo, Julie; Trent, Jonathan D

2014-01-01

OMEGA is an integrated aquatic system to produce biofuels, treat and recycle wastewater, capture CO2, and expand aquaculture production. This system includes floating photobioreactors (PBRs) that will cover hundreds of hectares in marine bays. To assess the interactions of marine mammals and birds with PBRs, 9 × 1.3 m flat panel and 9.5 × 0.2 m tubular PBRs were deployed in a harbor and monitored day and night from October 10, 2011 to Janurary 22, 2012 using infrared video. To observe interactions with pinnipeds, two trained sea lions (Zalophus californianus) and one trained harbor seal (Phoca vitulina richardii) were observed and directed to interact with PBRs in tanks. To determine the forces required to puncture PBR plastic and the effects of weathering, Instron measurements were made with a sea otter (Enhydra lutris) tooth and bird beaks. A total of 1,445 interactions of marine mammals and birds with PBRs were observed in the 2,424 hours of video recorded. The 95 marine mammal interactions, 94 by sea otters and one by a sea lion had average durations of three minutes (max 44 min) and represented about 1% of total recording time. The 1,350 bird interactions, primarily coots (Fulica americana) and gulls (Larus occidentalis and L. californicus) had average durations of six minutes (max. 170) and represented 5% of recording time. Interactive behaviors were characterized as passive (feeding, walking, resting, grooming, and social activity) or proactive (biting, pecking, investigating, and unspecified manipulating). Mammal interactions were predominantly proactive, whereas birds were passive. All interactions occurred primarily during the day. Ninety-six percent of otter interactions occurred in winter, whereas 73% of bird interactions in fall, correlating to their abundance in the harbor. Trained pinnipeds followed most commands to bite, drag, and haul-out onto PBRs, made no overt undirected interactions with the PBRs, but showed avoidance behavior to PBR tethers. Instron measurements indicated that sea-otter teeth and gull beaks can penetrate weathered plastic more easily than new plastic. Otter and bird interactions with experimental PBRs were benign. Large-scale OMEGA systems are predicted to have both positive and negative environmental consequences.

Comparative functional anatomy of hindlimb muscles and bones with reference to aquatic adaptation of the sea otter.

PubMed

Mori, Kent; Suzuki, Satoshi; Koyabu, Daisuke; Kimura, Junpei; Han, Sung-Yong; Endo, Hideki

2015-05-01

Although the sea otter (Enhydra lutris) is a complete aquatic species, spending its entire life in the ocean, it has been considered morphologically to be a semi-aquatic animal. This study aimed to clarify the unique hindlimb morphology and functional adaptations of E. lutris in comparison to other Mustelidae species. We compared muscle mass and bone measurements of five Mustelidae species: the sea otter, Eurasian river otter (Lutra lutra), American mink (Neovison vison), Japanese weasel (Mustela itatsi) and Siberian weasel (M. sibirica). In comparison with the other 4 species, E. lutris possessed significantly larger gluteus, popliteus and peroneus muscles, but smaller adductor and ischiopubic muscles. The popliteus muscle may act as a medial rotator of the crus, and the peroneus muscle may act as an abductor of the fifth toe and/or the pronator of the foot. The bundles of the gluteus superficialis muscle of E. lutris were fused with those of the tensor fasciae latae muscle and gluteofemoralis muscles, and they may play a role in femur abduction. These results suggest that E. lutris uses the abducted femur, medially rotated crus, eversion of the ankle and abducted fifth digit or extended interdigital web as a powerful propulsion generator. Therefore, we conclude that E. lutris is a complete aquatic animal, possessing differences in the proportions of the hindlimb muscles compared with those in other semi-aquatic and terrestrial mustelids.

Density dependence and risk of extinction in a small population of sea otters

USGS Publications Warehouse

Gerber, L.R.; Buenau, K.E.; VanBlaricom, G.

2004-01-01

Sea otters (Enhydra lutris (L.)) were hunted to extinction off the coast of Washington State early in the 20th century. A new population was established by translocations from Alaska in 1969 and 1970. The population, currently numbering at least 550 animals, A major threat to the population is the ongoing risk of majour oil spills in sea otter habitat. We apply population models to census and demographic data in order to evaluate the status of the population. We fit several density dependent models to test for density dependence and determine plausible values for the carrying capacity (K) by comparing model goodness of fit to an exponential model. Model fits were compared using Akaike Information Criterion (AIC). A significant negative relationship was found between the population growth rate and population size (r2=0.27, F=5.57, df=16, p<0.05), suggesting density dependence in Washington state sea otters. Information criterion statistics suggest that the model is the most parsimonious, followed closely by the logistic Beverton-Holt model. Values of K ranged from 612 to 759 with best-fit parameter estimates for the Beverton-Holt model including 0.26 for r and 612 for K. The latest (2001) population index count (555) puts the population at 87-92% of the estimated carrying capacity, above the suggested range for optimum sustainable population (OSP). Elasticity analysis was conducted to examine the effects of proportional changes in vital rates on the population growth rate (??). The elasticity values indicate the population is most sensitive to changes in survival rates (particularly adult survival).

Ultrastructural and molecular confirmation of the development of Sarcocystis neurona tissue cysts in the central nervous system of southern sea otters (Enhydra lutris nereis).

PubMed

Miller, M A; Barr, B C; Nordhausen, R; James, E R; Magargal, S L; Murray, M; Conrad, P A; Toy-Choutka, S; Jessup, D A; Grigg, M E

2009-10-01

In 2004, three wild sea otters were diagnosed with putative Sarcocystis neurona-associated meningoencephalitis by histopathology and immunohistochemistry. Schizonts, free merozoites and tissue cysts were observed in the brains of all three infected animals. Tissue cysts walls from sea otter 1 (SO1) stained positively using anti-S. neurona polyclonal antiserum. However, positive staining does not preclude infection by closely related or cross-reactive tissue cyst-forming coccidian parasites. Two immature tissue cysts in the brain of SO1 were examined using transmission electron microscopy. Ultrastructural features included cyst walls with thin villous projections up to 1 microm long with tapered ends and a distinctive, electron-dense outer lining layer composed of linearly-arranged, semi-circular structures with a "hobnailed" surface contour. Small numbers of microtubules extended down through the villi into the underlying granular layer. Metrocytes were short and plump with an anterior apical complex, 22 sub-pellicular microtubules, numerous free ribosomes and no rhoptries. Some metrocytes appeared to be dividing, with two adjacent nuclear profiles. Collectively these ultrastructural features were compatible with developing protozoal cysts and were similar to prior descriptions of S. neurona tissue cysts. Panspecific 18S rDNA primers were utilized to identify protozoa infecting the brains of these otters and DNA amplification and additional sequencing at the ITS1 locus confirmed that all three otters were infected with S. neurona. No other Sarcocystis spp. were detected in the brains or skeletal muscles of these animals by immunohistochemistry or PCR. We believe this is the first ultrastructural and molecular confirmation of the development of S. neurona tissue cysts in the CNS of any animal.

Ultrastructural and molecular confirmation of the development of Sarcocystis neurona tissue cysts in the central nervous system of southern sea otters (Enhydra lutris nereis)

PubMed Central

Miller, M.A.; Barr, B.C.; Nordhausen, R.; James, E.R.; Magargal, S.L.; Murray, M.; Conrad, P.A.; Toy-Choutka, S.; Jessup, D.A.; Grigg, M.E.

2009-01-01

In 2004, three wild sea otters were diagnosed with putative Sarcocystis neurona-associated meningoencephalitis by histopathology and immunohistochemistry. Schizonts, free merozoites and tissue cysts were observed in the brains of all three infected animals. Tissue cysts from sea otter 1 (SO1) stained positively using anti-S. neurona polyclonal antiserum. However, positive staining does not preclude infection by closely related or cross-reactive tissue cyst-forming coccidian parasites. Two immature tissue cysts in the brain of SO1 were examined using transmission electron microscopy. Ultrastructural features included cyst walls with thin villous projections up to 1 μm long with tapered ends and a distinctive, electron-dense outer lining layer composed of linearly-arranged, semi-circular structures with a “hobnailed” surface contour. Small numbers of microtubules extended down through the villi into the underlying granular layer. Metrocytes were short and plump with an anterior apical complex, 22 subpellicular microtubules, numerous free ribosomes and no rhoptries. Some metrocytes appeared to be dividing, with two adjacent nuclear profiles. Collectively these ultrastructural features were compatible with developing protozoal cysts and were similar to prior descriptions of S. neurona tissue cysts. Panspecific 18S rDNA primers were utilized to identify protozoa infecting the brains of these otters and DNA amplification and additional sequencing at the ITS1 locus confirmed that all three otters were infected with S. neurona. No other Sarcocystis spp. were detected in the brains or skeletal muscles of these animals by immunohistochemistry or PCR. We believe this is the first ultrastructural and molecular confirmation of the development of S. neurona tissue cysts in the CNS of any animal. PMID:19527725

Permissible Home Range Estimation (PHRE) in restricted habitats: A new algorithm and an evaluation for sea otters

USGS Publications Warehouse

Tarjan, Lily M; Tinker, M. Tim

2016-01-01

Parametric and nonparametric kernel methods dominate studies of animal home ranges and space use. Most existing methods are unable to incorporate information about the underlying physical environment, leading to poor performance in excluding areas that are not used. Using radio-telemetry data from sea otters, we developed and evaluated a new algorithm for estimating home ranges (hereafter Permissible Home Range Estimation, or “PHRE”) that reflects habitat suitability. We began by transforming sighting locations into relevant landscape features (for sea otters, coastal position and distance from shore). Then, we generated a bivariate kernel probability density function in landscape space and back-transformed this to geographic space in order to define a permissible home range. Compared to two commonly used home range estimation methods, kernel densities and local convex hulls, PHRE better excluded unused areas and required a smaller sample size. Our PHRE method is applicable to species whose ranges are restricted by complex physical boundaries or environmental gradients and will improve understanding of habitat-use requirements and, ultimately, aid in conservation efforts.

Sarcocystis neurona retinochoroiditis in a sea otter (Enhydra lutris kenyoni)

USGS Publications Warehouse

Dubey, J.P.; Thomas, N.J.

2011-01-01

Sarcocystis neurona is an important cause of fatal disease in sea otters in the USA. Encephalitis is the predominant lesion and parasites are confined to the central nervous system and muscles. Here we report retinochoroiditis in a sea otter (Enhydra lutris kenyoni) found dead on Copalis Beach, WA, USA. Salient lesions were confined to the brain and eye. Multifocal nonsuppurative meningoencephalitis was present in the cerebrum and cerebellum associated with S. neurona schizonts. The retina of one eye had a focus of inflammation that contained numerous S. neurona schizonts and merozoites. The focus extended from the retinal pigment epithelium inward through all layers of the retina, but inflammation was most concentrated at the inner surface of the tapetum and the outer retina. The inner and outer nuclear layers of the retina were disorganized and irregular at the site of inflammation. There was severe congestion and mild hemorrhage in the choroid, and mild hemorrhage into the vitreous body. Immunohistochemistry with S. neurona-specific polyclonal rabbit antibodies stained schizonts and merozoites. To our knowledge this is the first report of S. neurona-associated retinochoroiditis in any naturally infected animal.

Distribution, age, and sex composition of sea otter carcasses recovered during the response to the T/V Exxon Valdez oil spill

USGS Publications Warehouse

DeGange, Anthony R.; Lensink, Calvin J.; Bayha, Keith; Kormendy, Jennifer

1990-01-01

Nearly 900 sea otter (Enhydra lutris) carcasses were recovered in or adjacent to coastal areas affected by the T/V Exxon Valdez oil spill. The time of carcass recovery and the condition of carcasses indicate that most oil spill-induced mortality occurred early in the response period. In fact, by 19 May about 70% of the carcasses had been found. The majority of the carcasses (56%) were from Prince William Sound, suggesting that mortality was more acute there than in other geographic areas. Examination of the recovered carcasses indicated that more adult female sea otters were killed by the oil in Prince William Sound and along the Kenai Peninsula than other sex and age cohorts, reflecting greater abundance of adult females in those regions. Many of the adult females in those areas were pregnant or lactating. Pups made up a higher proportion of the carcasses collected in the western portion of the spill zone, reflecting the advanced pupping chronology at the time the search effort reached the Alaska Peninsula and the Kodiak Archipelago.

50 CFR 648.144 - Black sea bass gear restrictions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Black sea bass gear restrictions. 648.144... Measures for the Black Sea Bass Fishery § 648.144 Black sea bass gear restrictions. (a) Trawl gear restrictions—(1) General. (i) Otter trawlers whose owners are issued a black sea bass moratorium permit and...

50 CFR 648.144 - Black sea bass gear restrictions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Black sea bass gear restrictions. 648.144... Measures for the Black Sea Bass Fishery § 648.144 Black sea bass gear restrictions. (a) Trawl gear restrictions—(1) General. (i) Otter trawlers whose owners are issued a black sea bass moratorium permit and...

50 CFR 648.144 - Black sea bass gear restrictions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Black sea bass gear restrictions. 648.144... Measures for the Black Sea Bass Fishery § 648.144 Black sea bass gear restrictions. (a) Trawl gear restrictions—(1) General. (i) Otter trawlers whose owners are issued a black sea bass moratorium permit and...

Hydrodynamic characteristics of the double-winged otter board in the deep waters of the Mauritanian Sea

NASA Astrophysics Data System (ADS)

Su, Xin; Lu, Huosheng; Feng, Bo; Chen, Qiujie; Yan, Yunrong

2017-09-01

In this paper, we tested the hydrodynamic characteristics of a new, double-winged otter board that consists of a forewing, a leading edge slat and a trailing edge flap. Flume experiments were conducted in a circulating flume tank by using a model with an aspect ratio (AR) of 0.85 and a horizontal planform area (S) of 0.09 m2. The results indicated that the critical angle (αcr) of the model was 44°, whereas the maximum lift coefficient (C Lmax) was up to 1.715, and the door efficiency (K) was 1.122. The attack angle (α) ranged from 30° to 48° and from 10° to 46° when the lift coefficient (C L) and door efficiency (K) were greater than 1.2 and 1.0, respectively. To compare the difference between double-winged otter board and traditional Morgere Polyvalent Ovale, same model of Morgere Polyvalent Ovale was also tested under the same experimental conditions. The critical angle (αcr) and maximum of lift coefficient (C Lmax) of the doublewinged otter board were 37.5% and 14.6% larger than those of the Morgere Polyvalent Ovale. Therefore, we concluded that the novel, double-winged otter board was more suitable for bottom trawling fisheries in the deep water of the Mauretania Sea due to its better hydrodynamic characteristics and stability.

Vertebrate behavior and ecology. Progress report, July 1, 1977-May 31, 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tester, J R; Siniff, D B

Engineering design and development concentrated on five aspects during the past year: (1) development of high power output transmitters for monitoring animals from greater distances; (2) improvement and updating of a sonic transmitting and receiving system for monitoring fish and marine mammals; (3) design and testing of corrosive links which permit a transmitter to release from an animal at a specified time; (4) development of high frequency transmitters; and (5) development and testing of time delay transmitters. Field efforts resulted in further information on activity patterns and movements of sea otters in California and Alaska and of walleye pike inmore » experimental channels. Three manuscripts and two theses presented as part of this report describe these aspects in detail.« less

An estimation of carrying capacity for sea otters along the California coast

USGS Publications Warehouse

Laidre, K.L.; Jameson, R.J.; DeMaster, D.P.

2001-01-01

Eggs of wild birds collected for the purpose of measuring concentrations of pesticides or other pollutants vary from nearly fresh to nearly dry so that objective comparisons cannot be made on the basis of weight of the contents at the time of collection. Residue concentrations in the nearly dry eggs can be greatly exaggerated by this artifact. Valid interpretation of residue data depends upon compensation for these losses. A method is presented for making adjustments on the basis of volume of the egg, and formulas are derived for estimating the volume of eggs of eagles, ospreys, and pelicans from egg measurements. The possibility of adjustments on the basis of percentage of moisture, solids, or fat in fresh eggs is discussed also.

Modeling the Effects of Mortality on Sea Otter Populations

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.

2010-01-01

Conservation and management of sea otters can benefit from managing the magnitude and sex composition of human related mortality, including harvesting within sustainable levels. Using age and sex-specific reproduction and survival rates from field studies, we created matrix population models representing sea otter populations with growth rates of 1.005, 1.072, and 1.145, corresponding to stable, moderate, and rapid rates of change. In each modeled population, we incrementally imposed additional annual mortality over a 20-year period and calculated average annual rates of change (lambda). Additional mortality was applied to (1) males only, (2) at a 1:1 ratio of male to female, and (3) at a 3:1 ratio of male to female. Dependent pups (age 0-0.5) were excluded from the mortality. Maintaining a stable or slightly increasing population was largely dependent on (1) the magnitude of additional mortality, (2) the underlying rate of change in the population during the period of additional mortality, and (3) the extent that females were included in the additional mortality (due to a polygnous reproductive system where one male may breed with more than one female). In stable populations, additional mortality as high as 2.4 percent was sustainable if limited to males only, but was reduced to 1.2 percent when males and females were removed at ratios of 3:1 or 0.5 percent at ratios of 1:1. In moderate growth populations, additional mortality of 9.8 percent (male-only) and 15.0 percent (3:1 male to female) maximized the sustainable mortality about 3-10 ten-fold over the stable population levels. However, if additional mortality consists of males and females at equal proportions, the sustainable rate is 7.7 percent. In rapid growth populations, maximum sustainable levels of mortality as high as 27.3 percent were achieved when the ratio of additional mortality was 3:1 male to female. Although male-only mortality maximized annual harvest in stable populations, high male biased mortality in all simulations eventually led to low proportions of males, leading to instability in projected populations over time. Our findings identify the critical need to understand underlying rates of change that can be acquired only through frequent monitoring of managed populations. Models could be improved through better understanding of the effects of density and demographic and environmental stochasticity on sea otter vital rates. Although our primary objective was to provide information useful in managing harvests of sea otters, our findings have implications for the conservation and management of sea otter populations subjected to other sources of mortality that can be quantified, such as incidental, accidental, or illegal.

Serological evidence of Toxoplasma gondii infection in captive marine mammals in Mexico.

PubMed

Alvarado-Esquivel, C; Sánchez-Okrucky, R; Dubey, J P

2012-03-23

Toxoplasma gondii infection in marine mammals is important because they are considered as a sentinel for contamination of seas with T. gondii oocysts, and toxoplasmosis causes mortality in these animals, particularly sea otters. Serological evidence of T. gondii infection was determined in 75 captive marine mammals from four facilities in southern and central geographical regions in Mexico using the modified agglutination test (MAT). Antibodies (MAT, 1:25 or higher) to T. gondii were found in 55 (87.3%) of 63 Atlantic bottlenose dolphins (Tursiops truncatus truncatus), 3 of 3 Pacific bottlenose dolphins (Tursiops truncatus gillii), 2 of 4 California sea lions (Zalophus californianus), but not in 3 West Indian manatees (Trichechus manatus), and 2 Patagonian sea lions (Otaria flavescens). Seropositive marine mammals were found in all 4 (100%) facilities sampled. All marine mammals were healthy and there has not been any case of clinical toxoplasmosis in the facilities sampled for at least the last 15 years. The seroprevalence of T. gondii infection in marine mammals of the same species did not vary significantly with respect to sex and age. This is the first report on the detection of antibodies to T. gondii in marine mammals in Mexico. Published by Elsevier B.V.

Comparative functional anatomy of hindlimb muscles and bones with reference to aquatic adaptation of the sea otter

PubMed Central

MORI, Kent; SUZUKI, Satoshi; KOYABU, Daisuke; KIMURA, Junpei; HAN, Sung-Yong; ENDO, Hideki

2015-01-01

Although the sea otter (Enhydra lutris) is a complete aquatic species, spending its entire life in the ocean, it has been considered morphologically to be a semi-aquatic animal. This study aimed to clarify the unique hindlimb morphology and functional adaptations of E. lutris in comparison to other Mustelidae species. We compared muscle mass and bone measurements of five Mustelidae species: the sea otter, Eurasian river otter (Lutra lutra), American mink (Neovison vison), Japanese weasel (Mustela itatsi) and Siberian weasel (M. sibirica). In comparison with the other 4 species, E. lutris possessed significantly larger gluteus, popliteus and peroneus muscles, but smaller adductor and ischiopubic muscles. The popliteus muscle may act as a medial rotator of the crus, and the peroneus muscle may act as an abductor of the fifth toe and/or the pronator of the foot. The bundles of the gluteus superficialis muscle of E. lutris were fused with those of the tensor fasciae latae muscle and gluteofemoralis muscles, and they may play a role in femur abduction. These results suggest that E. lutris uses the abducted femur, medially rotated crus, eversion of the ankle and abducted fifth digit or extended interdigital web as a powerful propulsion generator. Therefore, we conclude that E. lutris is a complete aquatic animal, possessing differences in the proportions of the hindlimb muscles compared with those in other semi-aquatic and terrestrial mustelids. PMID:25715875

Tools for quantifying isotopic niche space and dietary variation at the individual and population level.

USGS Publications Warehouse

Newsome, Seth D.; Yeakel, Justin D.; Wheatley, Patrick V.; Tinker, M. Tim

2012-01-01

Ecologists are increasingly using stable isotope analysis to inform questions about variation in resource and habitat use from the individual to community level. In this study we investigate data sets from 2 California sea otter (Enhydra lutris nereis) populations to illustrate the advantages and potential pitfalls of applying various statistical and quantitative approaches to isotopic data. We have subdivided these tools, or metrics, into 3 categories: IsoSpace metrics, stable isotope mixing models, and DietSpace metrics. IsoSpace metrics are used to quantify the spatial attributes of isotopic data that are typically presented in bivariate (e.g., δ13C versus δ15N) 2-dimensional space. We review IsoSpace metrics currently in use and present a technique by which uncertainty can be included to calculate the convex hull area of consumers or prey, or both. We then apply a Bayesian-based mixing model to quantify the proportion of potential dietary sources to the diet of each sea otter population and compare this to observational foraging data. Finally, we assess individual dietary specialization by comparing a previously published technique, variance components analysis, to 2 novel DietSpace metrics that are based on mixing model output. As the use of stable isotope analysis in ecology continues to grow, the field will need a set of quantitative tools for assessing isotopic variance at the individual to community level. Along with recent advances in Bayesian-based mixing models, we hope that the IsoSpace and DietSpace metrics described here will provide another set of interpretive tools for ecologists.

Sea otter dental enamel is highly resistant to chipping due to its microstructure

PubMed Central

Ziscovici, Charles; Lucas, Peter W.; Constantino, Paul J.; Bromage, Timothy G.; van Casteren, Adam

2014-01-01

Dental enamel is prone to damage by chipping with large hard objects at forces that depend on chip size and enamel toughness. Experiments on modern human teeth have suggested that some ante-mortem chips on fossil hominin enamel were produced by bite forces near physiological maxima. Here, we show that equivalent chips in sea otter enamel require even higher forces than human enamel. Increased fracture resistance correlates with more intense enamel prism decussation, often seen also in some fossil hominins. It is possible therefore that enamel chips in such hominins may have formed at even greater forces than currently envisaged. PMID:25319817

Patterns and processes of population change in selected nearshore vertebrate predators

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.; Dean, T.A.; Esler, Daniel N.

2003-01-01

Sea otters and harlequin ducks have not fully recovered from the oil spill. This project will explore links between oil exposure and the lack of population recovery, with the intent of understanding constraints to recovery of these species and the nearshore environment. In FY 02, sea otter work will include aerial surveys of distribution and abundance and estimates of age-specific survival rates. Harlequin duck field studies will examine the relationship between survival and CYP1A. Captive experiments on harlequin ducks will examine the relationships between oil exposure and CYP1A induction, and metabolic and behavioral consequences of exposure.

Sarcocystis neurona retinochoroiditis in a sea otter (Enhydra lutris kenyoni).

PubMed

Dubey, J P; Thomas, N J

2011-12-29

Sarcocystis neurona is an important cause of fatal disease in sea otters in the USA. Encephalitis is the predominant lesion and parasites are confined to the central nervous system and muscles. Here we report retinochoroiditis in a sea otter (Enhydra lutris kenyoni) found dead on Copalis Beach, WA, USA. Salient lesions were confined to the brain and eye. Multifocal nonsuppurative meningoencephalitis was present in the cerebrum and cerebellum associated with S. neurona schizonts. The retina of one eye had a focus of inflammation that contained numerous S. neurona schizonts and merozoites. The focus extended from the retinal pigment epithelium inward through all layers of the retina, but inflammation was most concentrated at the inner surface of the tapetum and the outer retina. The inner and outer nuclear layers of the retina were disorganized and irregular at the site of inflammation. There was severe congestion and mild hemorrhage in the choroid, and mild hemorrhage into the vitreous body. Immunohistochemistry with S. neurona-specific polyclonal rabbit antibodies stained schizonts and merozoites. To our knowledge this is the first report of S. neurona-associated retinochoroiditis in any naturally infected animal. Copyright © 2011 Elsevier B.V. All rights reserved.

Sarcocystis neurona retinochoroiditis in a sea otter (Enhydra lutris kenyoni)

USGS Publications Warehouse

Dubey, J.P.; Thomas, N.J.

2011-01-01

Sarcocystis neurona is an important cause of fatal disease in sea otters in the USA. Encephalitis is the predominant lesion and parasites are confined to the central nervous system and muscles. Here we report retinochoroiditis in a sea otter (Enhydra lutris kenyoni) found dead on Copalis Beach, WA, USA. Salient lesions were confined to the brain and eye. Multifocal nonsuppurative meningoencephalitis was present in the cerebrum and cerebellum associated with S. neurona schizonts. The retina of one eye had a focus of inflammation that contained numerous S. neurona schizonts and merozoites. The focus extended from the retinal pigment epithelium inward through all layers of the retina, but inflammation was most concentrated at the inner surface of the tapetum and the outer retina. The inner and outer nuclear layers of the retina were disorganized and irregular at the site of inflammation. There was severe congestion and mild hemorrhage in the choroid, and mild hemorrhage into the vitreous body. Immunohistochemistry with S. neurona-specific polyclonal rabbit antibodies stained schizonts and merozoites. To our knowledge this is the first report of S. neurona-associated retinochoroiditis in any naturally infected animal. ?? 2011 Elsevier B.V.

Interactions of marine mammals and birds with offshore membrane enclosures for growing algae (OMEGA)

PubMed Central

2014-01-01

Background OMEGA is an integrated aquatic system to produce biofuels, treat and recycle wastewater, capture CO2, and expand aquaculture production. This system includes floating photobioreactors (PBRs) that will cover hundreds of hectares in marine bays. To assess the interactions of marine mammals and birds with PBRs, 9 × 1.3 m flat panel and 9.5 × 0.2 m tubular PBRs were deployed in a harbor and monitored day and night from October 10, 2011 to Janurary 22, 2012 using infrared video. To observe interactions with pinnipeds, two trained sea lions (Zalophus californianus) and one trained harbor seal (Phoca vitulina richardii) were observed and directed to interact with PBRs in tanks. To determine the forces required to puncture PBR plastic and the effects of weathering, Instron measurements were made with a sea otter (Enhydra lutris) tooth and bird beaks. Results A total of 1,445 interactions of marine mammals and birds with PBRs were observed in the 2,424 hours of video recorded. The 95 marine mammal interactions, 94 by sea otters and one by a sea lion had average durations of three minutes (max 44 min) and represented about 1% of total recording time. The 1,350 bird interactions, primarily coots (Fulica americana) and gulls (Larus occidentalis and L. californicus) had average durations of six minutes (max. 170) and represented 5% of recording time. Interactive behaviors were characterized as passive (feeding, walking, resting, grooming, and social activity) or proactive (biting, pecking, investigating, and unspecified manipulating). Mammal interactions were predominantly proactive, whereas birds were passive. All interactions occurred primarily during the day. Ninety-six percent of otter interactions occurred in winter, whereas 73% of bird interactions in fall, correlating to their abundance in the harbor. Trained pinnipeds followed most commands to bite, drag, and haul-out onto PBRs, made no overt undirected interactions with the PBRs, but showed avoidance behavior to PBR tethers. Instron measurements indicated that sea-otter teeth and gull beaks can penetrate weathered plastic more easily than new plastic. Conclusions Otter and bird interactions with experimental PBRs were benign. Large-scale OMEGA systems are predicted to have both positive and negative environmental consequences. PMID:24955238

Black, green, and red abalones. Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest. )

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ault, J.S.

1985-03-01

Black, green, and red abalones (Haliotis cracherodii, H. fulgens, and H. rufescens, respectivley) are of commercial and ecological importance and are distributed widely along the California coast. The abalones are morphologically similar; species are distinguished by particular shell sculpture, color, and body characteristics. Their latitudinal and bathymetric distribution is stratified and most closely related to temperature. Small juveniles eat mainly microflora; adults eat primarily drift macro-algae, preferring specific brown or red algae, when available. Spawning occurs during summer; gonad ripening depends on food quality and quantity and water temperature. Larvae are lecithotrophic and remain planktonic for periods of 5 tomore » 14 days after hatching; settling is substrate specific. Postlarvae and adults require hard substrate for attachment. Juveniles are cryptic, adults usually more exposed. Growth rates are similar, although maximum size varies with species. Increases in shell length and body weight correlate positively with food abundance and temperature. Below depths of 6 m, sea urchins are major competitors for food and space. Predation by invertebrates is low. Decreased abalone production from central California is associated with range expansion and increased predation by sea otters, the major source of abalone mortality. General declines in California landings are due to mortality from improper picking and replacement, habitat degradation, and perhaps overfishing. Commercial and sport diving efforts have increased sharply, whereas annual landings of abalones declined from 1965 to 1982.« less

Patterns of seabird and marine mammal carcass deposition along the central California coast, 1980-1986

USGS Publications Warehouse

Bodkin, James L.; Jameson, Ronald J.

1991-01-01

At monthly intervals from February 1980 through December 1986, a 14.5-km section of central California coastline was systematically surveyed for beach-cast carcasses of marine birds and mammals. Five hundred and fifty-four bird carcasses and 194 marine mammal carcasses were found. Common murres, western grebes, and Brandt's cormorants composed 45% of the bird total. California sea lions, sea otters, and harbor seals composed 90% of the mammal total. Several factors appeared to affect patterns of carcass deposition. The El Niño – Southern Oscillation (ENSO) of 1982–1983 was the dominant influence in terms of interannual variation in carcass deposition. During this ENSO, 56% of the seabirds and 48% of the marine mammals washed ashore. Patterns of intra-annual variation were species specific and were related to animal migration patterns, reproduction, and seasonal changes in weather. Nearshore currents and winds influenced the general area of carcass deposition, while beach substrate type and local patterns of sand deposition influenced the location of carcass deposition on a smaller spatial scale. Weekly surveys along a 1.1-km section of coastline indicated that 62% of bird carcasses and 41% of mammal carcasses remained on the beach less than 9 days. Cause of death was determined for only 8% of the carcasses. Oiling was the most common indication of cause of death in birds (6%). Neonates composed 8% of all mammal carcasses.

Osmoregulation in marine mammals

NASA Technical Reports Server (NTRS)

Ortiz, R. M.

2001-01-01

Osmoregulation in marine mammals has been investigated for over a century; however, a review of recent advances in our understanding of water and electrolyte balance and of renal function in marine mammals is warranted. The following topics are discussed: (i) kidney structure and urine concentrating ability, (ii) sources of water, (iii) the effects of feeding, fasting and diving, (iv) the renal responses to infusions of varying salinity and (v) hormonal regulation. The kidneys of pinnipeds and cetaceans are reniculate in structure, unlike those of terrestrial mammals (except bears), but this difference does not confer any greater concentrating ability. Pinnipeds, cetaceans, manatees and sea otters can concentrate their urine above the concentration of sea water, but only pinnipeds and otters have been shown to produce urine concentrations of Na+ and Cl- that are similar to those in sea water. This could afford them the capacity to drink sea water and not lose fresh water. However, with few exceptions, drinking is not a common behavior in pinnipeds and cetaceans. Water balance is maintained in these animals via metabolic and dietary water, while incidental ingestion and dietary salt may help maintain electrolyte homeostasis. Unlike most other aquatic mammals, sea otters commonly drink sea water and manatees frequently drink fresh water. Among the various taxonomic groups of marine mammals, the sensitivity of the renin-angiotensin-aldosterone system appears to be influenced by the availability of Na+. The antidiuretic role of vasopressin remains inconclusive in marine mammals, while the natriuretic function of atrial natriuretic peptide has yet to be examined. Ideas on the direction of future studies are presented.

Visual pigments of marine carnivores: pinnipeds, polar bear, and sea otter.

PubMed

Levenson, David H; Ponganis, Paul J; Crognale, Michael A; Deegan, Jess F; Dizon, Andy; Jacobs, Gerald H

2006-08-01

Rod and cone visual pigments of 11 marine carnivores were evaluated. Rod, middle/long-wavelength sensitive (M/L) cone, and short-wavelength sensitive (S) cone opsin (if present) sequences were obtained from retinal mRNA. Spectral sensitivity was inferred through evaluation of known spectral tuning residues. The rod pigments of all but one of the pinnipeds were similar to those of the sea otter, polar bear, and most other terrestrial carnivores with spectral peak sensitivities (lambda(max)) of 499 or 501 nm. Similarly, the M/L cone pigments of the pinnipeds, polar bear, and otter had inferred lambda(max) of 545 to 560 nm. Only the rod opsin sequence of the elephant seal had sensitivity characteristic of adaptation for vision in the marine environment, with an inferred lambda(max) of 487 nm. No evidence of S cones was found for any of the pinnipeds. The polar bear and otter had S cones with inferred lambda(max) of approximately 440 nm. Flicker-photometric ERG was additionally used to examine the in situ sensitivities of three species of pinniped. Despite the use of conditions previously shown to evoke cone responses in other mammals, no cone responses could be elicited from any of these pinnipeds. Rod photoreceptor responses for all three species were as predicted by the genetic data.

Social organization of sea otters in Prince William Sound, Alaska

USGS Publications Warehouse

Garshelis, David L.; Johnson, Ancel M.; Garshelis, Judith A.

1984-01-01

Sea otters in Prince William Sound. Alaska, were spatially segregated into predominantly (97%) male areas at the front of the expanding population and breeding areas with fewer (up to 33%) males. From 1975 to 1984 we captured and marked 267 otters with tags and (or) radio transmitters and investigated their reproductive strategies, social relationships, and patterns of sexual segregation. Mating occurred year-round, but peaked in September and October. Females first bred at 4 years of age and were capable of pupping annually; they generally separated from their pup before mating. Males established breeding territories that enabled prolonged precopulatory interactions that may have prompted female–pup separation and post-copulatory interactions that precluded females from mating with other males. Male mating success was related to age, weight, territory quality, and the length of time they maintained their territory. After the breeding season, territorial males returned to male areas where food was more abundant. Young, dispersing males also entered male areas and remained there until attaining breeding age. In male areas, otters commonly rested in groups of >50 individuals. Gregariousness promoted social interactions and likely enhanced food finding and (historically) predator protection. As food diminished, males moved into adjacent, unoccupied regions; females then occupied former male areas.

A New Pathogen Transmission Mechanism in the Ocean: The Case of Sea Otter Exposure to the Land-Parasite Toxoplasma gondii

PubMed Central

Mazzillo, Fernanda F. M.; Shapiro, Karen; Silver, Mary W.

2013-01-01

Toxoplasma gondii is a land-derived parasite that infects humans and marine mammals. Infections are a significant cause of mortality for endangered southern sea otters (Enhydra lutris nereis), but the transmission mechanism is poorly understood. Otter exposure to T. gondii has been linked to the consumption of marine turban snails in kelp (Macrocystis pyrifera) forests. It is unknown how turban snails acquire oocysts, as snails scrape food particles attached to surfaces, whereas T. gondii oocysts enter kelp beds as suspended particles via runoff. We hypothesized that waterborne T. gondii oocysts attach to kelp surfaces when encountering exopolymer substances (EPS) forming the sticky matrix of biofilms on kelp, and thus become available to snails. Results of a dietary composition analysis of field-collected snails and of kelp biofilm indicate that snails graze the dense kelp-biofilm assemblage composed of pennate diatoms and bacteria inserted within the EPS gel-like matrix. To test whether oocysts attach to kelp blades via EPS, we designed a laboratory experiment simulating the kelp forest canopy in tanks spiked with T. gondii surrogate microspheres and controlled for EPS and transparent exopolymer particles (TEP - the particulate form of EPS). On average, 19% and 31% of surrogates were detected attached to kelp surfaces covered with EPS in unfiltered and filtered seawater treatments, respectively. The presence of TEP in the seawater did not increase surrogate attachment. These findings support a novel transport mechanism of T. gondii oocysts: as oocysts enter the kelp forest canopy, a portion adheres to the sticky kelp biofilms. Snails grazing this biofilm encounter oocysts as ‘bycatch’ and thereby deliver the parasite to sea otters that prey upon snails. This novel mechanism can have health implications beyond T. gondii and otters, as a similar route of pathogen transmission may be implicated with other waterborne pathogens to marine wildlife and humans consuming biofilm-feeding invertebrates. PMID:24386100

Sea otter dental enamel is highly resistant to chipping due to its microstructure.

PubMed

Ziscovici, Charles; Lucas, Peter W; Constantino, Paul J; Bromage, Timothy G; van Casteren, Adam

2014-10-01

Dental enamel is prone to damage by chipping with large hard objects at forces that depend on chip size and enamel toughness. Experiments on modern human teeth have suggested that some ante-mortem chips on fossil hominin enamel were produced by bite forces near physiological maxima. Here, we show that equivalent chips in sea otter enamel require even higher forces than human enamel. Increased fracture resistance correlates with more intense enamel prism decussation, often seen also in some fossil hominins. It is possible therefore that enamel chips in such hominins may have formed at even greater forces than currently envisaged. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Biological and molecular characterizations of Toxoplasma gondii strains obtained from Southern sea otters (Enhydra lutris nereis)

USGS Publications Warehouse

Cole, Rebecca A.; Lindsay, D.S.; Howe, D.K.; Roderick, Constance L.; Dubey, J.P.; Thomas, N.J.; Baeten, L.A.

2000-01-01

Toxoplasma gondii was isolated from brain or heart tissue from 15 southern sea otters (Enhydra lutris nereis) in cell cultures. These strains were used to infect mice that developed antibodies to T. gondii as detected in the modified direct agglutination test and had T. gondii tissue cysts in their brains at necropsy. Mouse brains containing tissue cysts from 4 of the strains were fed to 4 cats. Two of the cats excreted T. gondii oocysts in their feces that were infectious for mice. Molecular analyses of 13 strains indicated that they were all type II strains, but that they were genetically distinct from one another.

Transplacental toxoplasmosis in a wild southern sea otter (Enhydra lutris nereis).

PubMed

Miller, Melissa; Conrad, Patricia; James, E R; Packham, Andrea; Toy-Choutka, Sharon; Murray, Michael J; Jessup, David; Grigg, Michael

2008-05-06

In September 2004, a neonatal sea otter pup was found alive on the beach in northern Monterey Bay, CA. Efforts to locate the mother were unsuccessful. Due to a poor prognosis for successful rehabilitation, the pup was euthanized. Postmortem examination revealed emaciation, systemic lymphadenopathy and a malformation of the left cerebral temporal lobe. On histopathology, free tachyzoites and tissue cysts compatible with Toxoplasma gondii were observed in the brain, heart, thymus, liver, lymph nodes and peri-umbilical adipose. The presence of T. gondii within host tissues was associated with lymphoplasmacytic inflammation and tissue necrosis. Immunofluorescent antibody tests using postmortem serum were positive for anti-T. gondii IgM and IgG (at 1:320 and 1:1280 serum dilution, respectively), but were negative for IgG directed against Sarcocystis neurona and Neospora caninum (<1:40 each). Brain immunohistochemistry revealed positive staining for tachyzoites and tissue cysts using antiserum raised to T. gondii, but not S. neurona or N. caninum. T. gondii parasite DNA was obtained from extracts of brain and muscle by PCR amplification using the diagnostic B1 locus. Restriction enzyme digestion followed by gel electrophoresis and DNA sequencing confirmed the presence of Type X T. gondii, the strain identified in the majority of southern sea otter infections.

Sequential megafaunal collapse in the North Pacific Ocean: An ongoing legacy of industrial whaling?

USGS Publications Warehouse

Springer, A.M.; Estes, J.A.; Van Vliet, Gus B.; Williams, T.M.; Doak, D.F.; Danner, E.M.; Forney, K.A.; Pfister, B.

2003-01-01

Populations of seals, sea lions, and sea otters have sequentially collapsed over large areas of the northern North Pacific Ocean and southern Bering Sea during the last several decades. A bottom-up nutritional limitation mechanism induced by physical oceanographic change or competition with fisheries was long thought to be largely responsible for these declines. The current weight of evidence is more consistent with top-down forcing. Increased predation by killer whales probably drove the sea otter collapse and may have been responsible for the earlier pinniped declines as well. We propose that decimation of the great whales by post-World War II industrial whaling caused the great whales' foremost natural predators, killer whales, to begin feeding more intensively on the smaller marine mammals, thus "fishing-down" this element of the marine food web. The timing of these events, information on the abundance, diet, and foraging behavior of both predators and prey, and feasibility analyses based on demographic and energetic modeling are all consistent with this hypothesis.

Sequential megafaunal collapse in the North Pacific Ocean: An ongoing legacy of industrial whaling?

PubMed Central

Springer, A. M.; Estes, J. A.; van Vliet, G. B.; Williams, T. M.; Doak, D. F.; Danner, E. M.; Forney, K. A.; Pfister, B.

2003-01-01

Populations of seals, sea lions, and sea otters have sequentially collapsed over large areas of the northern North Pacific Ocean and southern Bering Sea during the last several decades. A bottom-up nutritional limitation mechanism induced by physical oceanographic change or competition with fisheries was long thought to be largely responsible for these declines. The current weight of evidence is more consistent with top-down forcing. Increased predation by killer whales probably drove the sea otter collapse and may have been responsible for the earlier pinniped declines as well. We propose that decimation of the great whales by post-World War II industrial whaling caused the great whales' foremost natural predators, killer whales, to begin feeding more intensively on the smaller marine mammals, thus “fishing-down” this element of the marine food web. The timing of these events, information on the abundance, diet, and foraging behavior of both predators and prey, and feasibility analyses based on demographic and energetic modeling are all consistent with this hypothesis. PMID:14526101

Quantifying Population-Level Risks Using an Individual-Based Model: Sea Otters, Harlequin Ducks, and the Exxon Valdez Oil Spill

PubMed Central

Harwell, Mark A; Gentile, John H; Parker, Keith R

2012-01-01

Ecological risk assessments need to advance beyond evaluating risks to individuals that are largely based on toxicity studies conducted on a few species under laboratory conditions, to assessing population-level risks to the environment, including considerations of variability and uncertainty. Two individual-based models (IBMs), recently developed to assess current risks to sea otters and seaducks in Prince William Sound more than 2 decades after the Exxon Valdez oil spill (EVOS), are used to explore population-level risks. In each case, the models had previously shown that there were essentially no remaining risks to individuals from polycyclic aromatic hydrocarbons (PAHs) derived from the EVOS. New sensitivity analyses are reported here in which hypothetical environmental exposures to PAHs were heuristically increased until assimilated doses reached toxicity reference values (TRVs) derived at the no-observed-adverse-effects and lowest-observed-adverse-effects levels (NOAEL and LOAEL, respectively). For the sea otters, this was accomplished by artificially increasing the number of sea otter pits that would intersect remaining patches of subsurface oil residues by orders of magnitude over actual estimated rates. Similarly, in the seaduck assessment, the PAH concentrations in the constituents of diet, sediments, and seawater were increased in proportion to their relative contributions to the assimilated doses by orders of magnitude over measured environmental concentrations, to reach the NOAEL and LOAEL thresholds. The stochastic IBMs simulated millions of individuals. From these outputs, frequency distributions were derived of assimilated doses for populations of 500 000 sea otters or seaducks in each of 7 or 8 classes, respectively. Doses to several selected quantiles were analyzed, ranging from the 1-in-1000th most-exposed individuals (99.9% quantile) to the median-exposed individuals (50% quantile). The resulting families of quantile curves provide the basis for characterizing the environmental thresholds below which no population-level effects could be detected and above which population-level effects would be expected to become manifest. This approach provides risk managers an enhanced understanding of the risks to populations under various conditions and assumptions, whether under hypothetically increased exposure regimes, as demonstrated here, or in situations in which actual exposures are near toxic effects levels. This study shows that individual-based models are especially amenable and appropriate for conducting population-level risk assessments, and that they can readily be used to answer questions about the risks to individuals and populations across a variety of exposure conditions. Integr Environ Assess Manag 2012; 8: 503–522. © 2012 SETAC PMID:22275071

Quantifying population-level risks using an individual-based model: sea otters, Harlequin Ducks, and the Exxon Valdez oil spill.

PubMed

Harwell, Mark A; Gentile, John H; Parker, Keith R

2012-07-01

Ecological risk assessments need to advance beyond evaluating risks to individuals that are largely based on toxicity studies conducted on a few species under laboratory conditions, to assessing population-level risks to the environment, including considerations of variability and uncertainty. Two individual-based models (IBMs), recently developed to assess current risks to sea otters and seaducks in Prince William Sound more than 2 decades after the Exxon Valdez oil spill (EVOS), are used to explore population-level risks. In each case, the models had previously shown that there were essentially no remaining risks to individuals from polycyclic aromatic hydrocarbons (PAHs) derived from the EVOS. New sensitivity analyses are reported here in which hypothetical environmental exposures to PAHs were heuristically increased until assimilated doses reached toxicity reference values (TRVs) derived at the no-observed-adverse-effects and lowest-observed-adverse-effects levels (NOAEL and LOAEL, respectively). For the sea otters, this was accomplished by artificially increasing the number of sea otter pits that would intersect remaining patches of subsurface oil residues by orders of magnitude over actual estimated rates. Similarly, in the seaduck assessment, the PAH concentrations in the constituents of diet, sediments, and seawater were increased in proportion to their relative contributions to the assimilated doses by orders of magnitude over measured environmental concentrations, to reach the NOAEL and LOAEL thresholds. The stochastic IBMs simulated millions of individuals. From these outputs, frequency distributions were derived of assimilated doses for populations of 500,000 sea otters or seaducks in each of 7 or 8 classes, respectively. Doses to several selected quantiles were analyzed, ranging from the 1-in-1000th most-exposed individuals (99.9% quantile) to the median-exposed individuals (50% quantile). The resulting families of quantile curves provide the basis for characterizing the environmental thresholds below which no population-level effects could be detected and above which population-level effects would be expected to become manifest. This approach provides risk managers an enhanced understanding of the risks to populations under various conditions and assumptions, whether under hypothetically increased exposure regimes, as demonstrated here, or in situations in which actual exposures are near toxic effects levels. This study shows that individual-based models are especially amenable and appropriate for conducting population-level risk assessments, and that they can readily be used to answer questions about the risks to individuals and populations across a variety of exposure conditions. Copyright © 2012 SETAC.

Flow-cytometric determination of genotoxic effects of exposure to petroleum in mink and sea otters

USGS Publications Warehouse

Bickham, J.W.; Mazet, J.A.; Blake, J.; Smolen, M.J.; Lou, Y.; Ballachey, Brenda E.

1998-01-01

Three experiments were conducted to investigate the genotoxic effects of crude oil on mink and sea otters, In the first experiment, the effects on mink of chronic exposure to weathered Prudhoe Bay crude oil were studied, Female mink were fed a diet that included weathered crude oil for a period of 3 weeks prior to mating, during pregnancy and until weaning. Kits were exposed through lactation and by diet after weaning until 4 months of age. Kidney and liver tissues of the kits were examined using flow cytometry (FCM) and it was found that the genome size was increased in kidney samples from the experimental group compared to the control group. This effect was probably due to some type of DNA amplification and it could have been inherited from the exposed mothers or have been a somatic response to oil exposure in the pups, No evidence of clastogenic effects, as measured by the coefficient of variation (CV) of the G(1) peak, was found in kidney or liver tissue. In the second experiment, yearling female mink were exposed either by diet or externally to crude oil or bunker C fuel oil. Evidence for clastogenic damage was found in spleen tissue for the exposure groups, but not in kidney tissue. No evidence of increased genome size was observed. In the third experiment, blood was obtained from wild-caught sea otters in Prince William Sound. The sea otters represented two populations: one from western Prince William Sound that was potentially exposed to oil from the Exxon Valdez oil spill and a reference population from eastern Prince William Sound that did not receive oil from the spill. The spill had occurred 1.5 years prior to obtaining the blood samples. Although the mean CVs did not differ between the populations, the exposed population had a significantly higher variance of CV measurements and five out of 15 animals from the exposed population had CVs higher than the 95% confidence limits of the reference population, It is concluded that FCM is a sensitive indicator of the clastogenic effects of oil exposure and that haematopoietic tissues and blood are best for detecting clastogenic damage. Moreover, the observed differences in the genome size of the kidney cells mere possibly heritable effects, but this needs further investigation. Lastly, sea otters exposed to spilled oil 1.5 years earlier showed evidence of clastogenic damage in one-third of the individuals sampled.

Estimating age of sea otters with cementum layers in the first premolar

USGS Publications Warehouse

Bodkin, James L.; Ames, J.A.; Jameson, R.J.; Johnson, A.M.; Matson, G.M.

1997-01-01

We assessed sources of variation in the use of tooth cementum layers to determine age by comparing counts in premolar tooth sections to known ages of 20 sea otters (Enhydra lutris). Three readers examined each sample 3 times, and the 3 readings of each sample were averaged by reader to provide the mean estimated age. The mean (SE) of known age sample was 5.2 years (1.0) and the 3 mean estimated ages were 7.0 (1.0), 5.9 (1.1) and, 4.4 (0.8). The proportion of estimates accurate to within +/- 1 year were 0.25, 0.55, and 0.65 and to within +/- 2 years 0.65, 0.80, and 0.70, by reader. The proportions of samples estimated with >3 years error were 0.20, 0.10, and 0.05. Errors as large as 7, 6, and 5 years were made among readers. In few instances did all readers uniformly provide either accurate (error 1 yr) counts. In most cases (0.85), 1 or 2 of the readers provided accurate counts. Coefficients of determination (R2) between known ages and mean estimated ages were 0.81, 0.87, and 0.87, by reader. The results of this study suggest that cementum layers within sea otter premolar teeth likely are deposited annually and can be used for age estimation. However, criteria used in interpreting layers apparently varied by reader, occasionally resulting in large errors, which were not consistent among readers. While large errors were evident for some individual otters, there were no differences between the known and estimated age-class distribution generated by each reader. Until accuracy can be improved, application of this ageing technique should be limited to sample sizes of at least 6-7 individuals within age classes of >/=1 year.

Application of Multispectral and Hyperspectral Remote Sensing For Detection of Freshwater Harmful Algal Blooms

NASA Astrophysics Data System (ADS)

Kudela, R. M.; Accorsi, E.; Austerberry, D.; Palacios, S. L.

2013-12-01

Freshwater Cyanobacterial Harmful algal blooms (CHABs) represent a pressing and apparently increasing threat to both human and environmental health. In California, toxin producing blooms of several species, including Aphanizomenon, Microcystis, Lyngbya, and Anabaena are common; toxins from these blooms have been linked to impaired drinking water, domestic and wild animal deaths, and increasing evidence for toxin transfer to coastal marine environments, including the death of several California sea otters, a threatened marine species. California scientists and managers are under increasing pressure to identify and mitigate these potentially toxic blooms, but point-source measurements and grab samples have been less than effective. There is increasing awareness that these toxic events are both spatially widespread and ephememeral, leading to the need for better monitoring methods applicable to large spatial and temporal scales. Based on monitoring in several California water bodies, it appears that Aphanizomenon blooms frequently precede dangerous levels of toxins from Microcystis. We are exploring new detection methods for identifying CHABs and potentially distinguishing between blooms of the harmful cyanobacteria Aphanizomenon and Microcystis using remote sensing reflectance from a variety of airborne and satellite sensors. We suggest that Aphanizomenon blooms could potentially be used as an early warning of more highly toxic subsequent blooms, and that these methods, combined with better toxin monitoring, can lead to improved understanding and prediction of CHABs by pinpointing problematic watersheds.

Hematology and clinical chemistry of sea otters vaptured in Prince William Sound, Alaska following the Exxon Valdez Oil Spill

USGS Publications Warehouse

Rebar, A.H.; Ballachey, Brenda E.; Bruden, D.L.; Kloecker, Kimberly A.

1996-01-01

Hematologic and serum chemical analyses were performed on sea otter blood samples collected from 31 adult males, 63 adult females, and 42 pups captured in western Prince William Sound (oiled area), and 12 adult males, 40 adult females, and 15 pups captured in eastern Prince William Sound (unoiled area) in 1989 and 1990. Hematologic differences between eastern and western adult males were minimal. Both hematocrits and hemoglobins were higher in western than eastern otters but the biological significance of this is equivocal. Western males had higher absolute eosinophil counts, suggesting possible systemic hypersensitivity reactions. Western males had higher serum protein and serum globulin levels than eastern males, suggesting greater antigenic stimulation (more inflammatory and/or infectious conditions). There were no differences in hematologic parameters between eastern and western female otters. Some chemistry changes were present, but the degree of difference was small. Total protein and serum globulin levels were slightly higher in western females, a finding also seen in adult males. Mean levels of liver enzymes for western females were somewhat higher than for the eastern otters, suggesting the possibility of subclinical liver disease. As a group, western pup hematocrits, hemoglobins, and red cell counts were significantly lower than those of eastern pups. From a biological perspective, these reductions were minimal but supported by individual animal data. The red cell data suggest a mild anemia in western pups; however, the degree of anemia was minimal, so that biological significance was equivocal. Other hematologic and clinical chemical differences between eastern and western pups were not striking and were also of equivocal biological significance.

Incorporating diverse data and realistic complexity into demographic estimation procedures for sea otters

USGS Publications Warehouse

Tinker, M. Timothy; Doak, Daniel F.; Estes, James A.; Hatfield, Brian B.; Staedler, Michelle M.; Gross, Arthur

2006-01-01

Reliable information on historical and current population dynamics is central to understanding patterns of growth and decline in animal populations. We developed a maximum likelihood-based analysis to estimate spatial and temporal trends in age/sex-specific survival rates for the threatened southern sea otter (Enhydra lutris nereis), using annual population censuses and the age structure of salvaged carcass collections. We evaluated a wide range of possible spatial and temporal effects and used model averaging to incorporate model uncertainty into the resulting estimates of key vital rates and their variances. We compared these results to current demographic parameters estimated in a telemetry-based study conducted between 2001 and 2004. These results show that survival has decreased substantially from the early 1990s to the present and is generally lowest in the north-central portion of the population's range. The greatest temporal decrease in survival was for adult females, and variation in the survival of this age/sex class is primarily responsible for regulating population growth and driving population trends. Our results can be used to focus future research on southern sea otters by highlighting the life history stages and mortality factors most relevant to conservation. More broadly, we have illustrated how the powerful and relatively straightforward tools of information-theoretic-based model fitting can be used to sort through and parameterize quite complex demographic modeling frameworks. ?? 2006 by the Ecological Society of America.

50 CFR 82.5 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Polar bear. Enhydra lutris Sea Otter. Odobenus rosmarus Walrus. Dugong dugong Dugong. Trichechus... means any specimen of the following species, whether alive or dead, or any part thereof, including but...

50 CFR 82.5 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Polar bear. Enhydra lutris Sea Otter. Odobenus rosmarus Walrus. Dugong dugong Dugong. Trichechus... means any specimen of the following species, whether alive or dead, or any part thereof, including but...

50 CFR 82.5 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Polar bear. Enhydra lutris Sea Otter. Odobenus rosmarus Walrus. Dugong dugong Dugong. Trichechus... means any specimen of the following species, whether alive or dead, or any part thereof, including but...

50 CFR 82.5 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Polar bear. Enhydra lutris Sea Otter. Odobenus rosmarus Walrus. Dugong dugong Dugong. Trichechus... means any specimen of the following species, whether alive or dead, or any part thereof, including but...

76 FR 18725 - Marine Mammals; File Nos. 14330 and 14335

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-05

... (Phoca vitulina) on St. Paul, St. George, Otter, and Walrus Islands, and Sea Lion Rock, all of the... marine mammals in Alaska: (File No. 14330) the Aleut Community of St. Paul Island, Tribal Government, Ecosystem Conservation Office, St. Paul Island, AK; and (File No. 14335) the Alaska SeaLife Center, Seward...

Patterns of growth and body condition in sea otters from the Aleutian archipelago before and after the recent population decline

USGS Publications Warehouse

Laidre, K.L.; Estes, J.A.; Tinker, M.T.; Bodkin, James L.; Monson, Daniel H.; Schneider, K.

2006-01-01

1. Growth models for body mass and length were fitted to data collected from 1842 sea otters Enhydra lutris shot or live-captured throughout south-west Alaska between 1967 and 2004. Growth curves were constructed for each of two main year groups: 1967–71 when the population was at or near carrying capacity and 1992–97 when the population was in steep decline. Analyses of data collected from animals caught during 2004, when the population density was very low, were precluded by a small sample size and consequently only examined incidentally to the main growth curves.2. Growth curves demonstrated a significant increase in body mass and body length at age in the 1990s. Asymptotic values of body mass were 12–18% higher in the 1990s than in the 1960s/70s, and asymptotic values for body length were 10–11% higher between the same periods. Data collected in 2004 suggest a continued increase in body size, with nearly all data points for mass and length falling significantly above the 1990s growth curves.3. In addition to larger asymptotic values for mass and length, the rate of growth towards asymptotic values was more rapid in the 1990s than in the 1960s/70s: sea otters reached 95% of asymptotic body mass and body length 1–2 years earlier in the 1990s.4. Body condition (as measured by the log mass/log length ratio) was significantly greater in males than in females. There was also an increasing trend from the 1960s/70s through 2004 despite much year-to-year variation.5. Population age structures differed significantly between the 1960s/70s and the 1990s with the latter distribution skewed toward younger age classes (indicating an altered lxfunction) suggesting almost complete relaxation of age-dependent mortality patterns (i.e. those typical of food-limited populations).6. This study spanned a period of time over which the population status of sea otters in the Aleutian archipelago declined precipitously from levels at or near equilibrium densities at some islands in the 1960s/70s to < 5% of estimated carrying capacity by the late 1990s. The results of this study indicate an improved overall health of sea otters over the period of decline and suggest that limited nutritional resources were not the cause of the observed reduced population abundance. Our findings are consistent with the hypothesis that the decline was caused by increased killer whale predation.

Passive remote sensing of large-scale methane emissions from Oil Fields in California's San Joaquin Valley and validation by airborne in-situ measurements - Results from COMEX

NASA Astrophysics Data System (ADS)

Gerilowski, Konstantin; Krautwurst, Sven; Thompson, David R.; Thorpe, Andrew K.; Kolyer, Richard W.; Jonsson, Haflidi; Krings, Thomas; Frankenberg, Christian; Horstjann, Markus; Leifer, Ira; Eastwood, Michael; Green, Robert O.; Vigil, Sam; Fladeland, Matthew; Schüttemeyer, Dirk; Burrows, John P.; Bovensmann, Heinrich

2016-04-01

The CO2 and MEthane EXperiment (COMEX) was a NASA and ESA funded campaign in support of the HyspIRI and CarbonSat mission definition activities. As a part of this effort, seven flights were performed between June 3 and September 4, 2014 with the Methane Airborne MAPper (MAMAP) remote sensing instrument (operated by the University of Bremen in cooperation with the German Research Centre for Geosciences - GFZ) over the Kern River, Kern Front, and Poso Creek Oil Fields located in California's San Joaquin Valley. MAMAP was installed for the flights aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft, together with: a Picarro fast in-situ greenhouse gas (GHG) analyzer operated by the NASA Ames Research Center, ARC; a 5-hole turbulence probe; and an atmospheric measurement package operated by CIRPAS measuring aerosols, temperature, dew-point, and other atmospheric parameters. Three of the flights were accompanied by the Next Generation Airborne Visual InfraRed Imaging Spectrometer (AVIRIS-NG), operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology, installed aboard a second Twin Otter aircraft. Large-scale, high-concentration CH4 plumes were detected by the MAMAP instrument over the fields and tracked over several kilometers. The spatial distribution of the MAMAP observed plumes was compared to high spatial resolution CH4 anomaly maps derived by AVIRIS-NG imaging spectroscopy data. Remote sensing data collected by MAMAP was used to infer CH4 emission rates and their distributions over the three fields. Aggregated emission estimates for the three fields were compared to aggregated emissions inferred by subsequent airborne in-situ validation measurements collected by the Picarro instrument. Comparison of remote sensing and in-situ flux estimates will be presented, demonstrating the ability of airborne remote sensing data to provide accurate emission estimates for concentrations above the detection limit. This opens new applications of airborne atmospheric remote sensing in the area of anthropogenic top-down emission monitoring as well as for atmospheric CH4 leakage monitoring during accidents like the Elgin blow-out (March 2012) in the North Sea or the recent Aliso Canyon gas leak incident (2015/2016) in California.

Southern Sea Otter Recovery and Research Act

THOMAS, 111th Congress

Sen. Boxer, Barbara [D-CA

2009-10-01

Senate - 12/10/2010 Placed on Senate Legislative Calendar under General Orders. Calendar No. 686. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

California mussels (Mytilus californianus) as sentinels for marine contamination with Sarcocystis neurona.

PubMed

Michaels, Lauren; Rejmanek, Daniel; Aguilar, Beatriz; Conrad, Patricia; Shapiro, Karen

2016-05-01

Sarcocystis neurona is a terrestrial parasite that can cause fatal encephalitis in the endangered Southern sea otter (Enhydra lutris nereis). To date, neither risk factors associated with marine contamination nor the route of S. neurona infection to marine mammals has been described. This study evaluated coastal S. neurona contamination using California mussels (Mytilus californianus) as sentinels for pathogen pollution. A field investigation was designed to test the hypotheses that (1) mussels can serve as sentinels for S. neurona contamination, and (2) S. neurona contamination in mussels would be highest during the rainy season and in mussels collected near freshwater. Initial validation of molecular assays through sporocyst spiking experiments revealed the ITS-1500 assay to be most sensitive for detection of S. neurona, consistently yielding parasite amplification at concentrations ⩾5 sporocysts/1 mL mussel haemolymph. Assays were then applied on 959 wild-caught mussels, with detection of S. neurona confirmed using sequence analysis in three mussels. Validated molecular assays for S. neurona detection in mussels provide a novel toolset for investigating marine contamination with this parasite, while confirmation of S. neurona in wild mussels suggests that uptake by invertebrates may serve as a route of transmission to susceptible marine animals.

Military Readiness and Southern Sea Otter Conservation Act

THOMAS, 112th Congress

Rep. Gallegly, Elton [R-CA-24

2012-02-15

House - 07/17/2012 Reported (Amended) by the Committee on Natural Resources. H. Rept. 112-606, Part I. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

77 FR 58405 - Endangered Species; Marine Mammals; Receipt of Applications for Permit

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-20

..., Portola Valley, CA; PRT-83520A Applicant: Kevin Dunworth, Austin, TX; PRT-84493A Applicant: Timothy... scientific research. The specimens would be obtained opportunistically from sea otters taken from the wild in...

Characterization of the putatively introduced red alga Acrochaetium secundatum (Acrochaetiales, Rhodophyta) growing epizoically on the pelage of southern sea otters (Enhydra lutris nereis)

USGS Publications Warehouse

Bentall, Gena B.; Rosen, Barry H.; Kunz, Jessica M.; Miller, Melissa A.; Saunders, Gary W.; LaRoche, Nicole L.

2016-01-01

Ecological associations between epibionts (organisms that live on the surface of another living organism) and vertebrates have been documented in both marine and terrestrial environments, and may be opportunistic, commensal, or symbiotic (Lewin et al. 1981, Holmes 1985, Allen et al. 1993, Bledsoe et al. 2006, Pfaller et al. 2008, Suutari et al. 2010). Although epibiont proliferation is frequently reported on slow-moving, sparsely haired organisms such as manatees and sloths, reports from densely furred, highly mobile mammals are much less common. There are reports of epizoic algae for several species of pinnipeds (Kenyon and Rice 1959, Scheffer 1962, Baldridge 1977, Allen et al. 1993), which rely to varying degrees on both pelage and blubber for thermoregulation, but the phenomenon has not been widely described. Scheffer (1962) noted that red algae was fairly common on the pelage of northern fur seals (Callorhinus ursinus), pinnipeds for which fur likely makes a comparatively high contribution to thermoregulation (Donohue et al. 2000). For species with pelage that plays a critical role of thermal insulation, it seems implausible that an epibiont would persist on healthy individuals that devote significant energy resources toward grooming and actively maintaining their coat. Biological characteristics of epibiont settlement and attachment, and physiological requirements of epizoic species play key roles in their successful colonization and potential host impacts. To investigate this relationship, we explore a novel discovery of an epizoic alga from southern sea otters, including describing algal development on sea otter hair and molecular identification of the algae.

Southern Sea Otter Recovery and Research Act

THOMAS, 111th Congress

Rep. Farr, Sam [D-CA-17

2009-01-15

Senate - 07/29/2009 Received in the Senate and Read twice and referred to the Committee on Commerce, Science, and Transportation. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

MAIA pathfinder: Imaging Polarimetric Assessment and Characterization of Tropospheric Particulate Matter (ImPACT-PM) field campaign

NASA Astrophysics Data System (ADS)

Kalashnikova, O. V.; Seidel, F. C.; Xu, F.; Garay, M. J.; Wu, L.; Bruegge, C. J.; van Harten, G.; Val, S.; Diner, D. J.; Seinfeld, J.; Bates, K. H.; Cappa, C. D.; Bradley, C. L.; Kupinski, M.; Clements, C. B.; Camacho, C.; Yorks, J. E.

2016-12-01

The Multi-Angle Imager for Aerosols (MAIA) instrument, which was recently selected under NASA's third Earth Venture Instrument call, will improve aerosol particle type sensitivity through the atmospheric column as well as at the surface through the use of multiangular, multispectral, and polarimetric observations. MAIA will provide new information that enables estimates of speciated (size- and particle type classifications) surface particulate matter (PM) from space over major cities around the globe, and enable improved associations between particulate air pollution and human health. As a pathfinder to MAIA, the ImPACT-PM field campaign was a joint JPL/Caltech effort to combine measurements from MISR and AirMSPI with in situ airborne measurements and a chemical transport model to validate remote sensing retrievals of different types of airborne particulate matter. We will present highlights of the successfully completed ImPACT-PM field campaign which took place in the California Central Valley on July 5-8, 2016. We had two NASA ER-2/ CIRPAS Twin Otter collocated flights coincident with Terra/MISR overpasses on Tuesday and Thursday July 5 and 7; and two ER-2/Twin Otter collocations over local fires on Friday, July 8th. The AirMSPI, AirSPEX, and CPL instruments were integrated on the ER-2, and Caltech aerosol/cloud in-situ instruments were integrated on the CIRPAS Twin Otter aircraft in addition to the normal Twin Otter payload. We also deployed the JPL/University of Arizona GroundMSPI instrument and a ground-based lidar from San José State University at the Fresno California Air Resources Board super-site. While the overall aerosol and PM levels were low at this time, we were able to see a gradient of pollution in specially processed MISR high-resolution 4.4 km resolution aerosol data on both days. We will present initial results of AirMSPI WRF-Chem-constrained retrievals in comparison with EPA Speciation Trends Network stations in Fresno and Bakersfield, and with available AMS/DMA/SP2 instrument data from the Twin Otter. The SP2 instrument measured very high levels of carbon over the fire near Gorman on July 8 that was collocated with the AirMSPI/SPEX data. This provides a case to validate AirMSPI retrievals of absorbing particles.

Estimates of carrying capacity for sea otters in Washington state

USGS Publications Warehouse

Laidre, K.L.; Jameson, R.J.; Jeffries, S.J.; Hobbs, R.C.; Bowlby, C.E.; VanBlaricom, G.R.

2002-01-01

Analyses of eggs of three species of North American accipitrine hawks for organochlorines and heavy metals indicate that contamination with DDE may be the primary cause of recent population declines of two of the species, Cooper's hawk and sharp-shinned hawk.

Review of the systematics, biology and ecology of lice from pinnipeds and river otters (Insecta: Phthiraptera: Anoplura: Echinophthiriidae).

PubMed

Soledad Leonardi, Maria; Palma, Ricardo Luis

2013-01-01

We present a literature review of the sucking louse family Echinophthiriidae, its five genera and twelve species parasitic on pinnipeds (fur seals, sea lions, walruses, true seals) and the North American river otter. We give detailed synonymies and published records for all taxonomic hierarchies, as well as hosts, type localities and repositories of type material; we highlight significant references and include comments on the current taxonomic status of the species. We provide a summary of present knowledge of the biology and ecology for eight species. Also, we give a host-louse list, and a bibliography to the family as complete as possible.

Uptake and transmission of Toxoplasma gondii oocysts by migratory filter-feeding fish

EPA Science Inventory

Toxoplasma gondii is a ubiquitous parasitic protozoan known to cause disease and death in warm-blooded animals. Bottlenose dolphins, walruses, sea otters, and other marine animals worldwide have died from toxoplasmosis, but the source of this parasite in the marine environment h...

Analysis of the Meteorology Associated with the 1997 NASA Glenn Twin Otter Icing Events

NASA Technical Reports Server (NTRS)

Bernstein, Ben C.

2000-01-01

This part of the document contains an analysis of the meteorology associated with the premier icing encounters from the January-March 1997 NASA Twin Otter dataset. The purpose of this analysis is to provide a meteorological context for the aircraft data collected during these flights. For each case, the following data elements are presented: (1) A detailed discussion of the Twin Otter encounter, including locations, liquid water contents, temperatures and microphysical makeup of the clouds and precipitation aloft, (2) Upper-air charts, providing hand-analyzed locations of lows, troughs, ridges, saturated/unsaturated air, temperatures, warm/cold advection, and jet streams, (3) Balloon-borne soundings, providing vertical profiles of temperature, moisture and winds, (4) Infrared satellite data, providing cloud locations and cloud top temperature, (5) 3-hourly surface charts, providing hand-analyzed locations of lows, highs, fronts, precipitation (including type) and cloud cover, (6) Hourly plots of icing pilot reports, providing the icing intensity, icing type, icing altitudes and aircraft type, (7) Hourly, regional radar mosaics, providing fine resolution of the locations of precipitation (including intensity and type), pilot reports of icing (including intensity and type), surface observations of precipitation type and Twin Otter tracks for a one hour window centered on the time of the radar data, and (8) Plots of data from individual NEXRAD radars at times and elevation angles that have been matched to Twin Otter flight locations. Outages occurred in nearly every dataset at some point. All relevant data that was available is presented here. All times are in UTC and all heights are in feet above mean sea level (MSL).

75 FR 32497 - Marine Mammals; Incidental Take During Specified Activities

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-08

... of the proposed action is contained in a Final Environmental Assessment (FEA) and Finding of No..., status, distribution, and seasonal distribution of northern sea otters is contained in the FEA, the.... National Environmental Policy Act (NEPA) The applicant provided an FEA on the project. The Service finds...

77 FR 44264 - Endangered Species; Marine Mammals; Receipt of Applications for Permit

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-27

... felina), all sea otters (Enhydra lutris), walrus (Odobenus rosmarus), polar bear (Ursus [[Page 44266...-FF09A30000] Endangered Species; Marine Mammals; Receipt of Applications for Permit AGENCY: Fish and Wildlife... with endangered species, marine mammals, or both. With some exceptions, the Endangered Species Act (ESA...

50 CFR 14.132 - Food and water.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 50 Wildlife and Fisheries 1 2011-10-01 2011-10-01 false Food and water. 14.132 Section 14.132 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR TAKING..., Sea Otters, Pinnipeds, and Polar Bears) § 14.132 Food and water. A marine mammal shall not be...

50 CFR 14.132 - Food and water.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Food and water. 14.132 Section 14.132 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR TAKING..., Sea Otters, Pinnipeds, and Polar Bears) § 14.132 Food and water. A marine mammal shall not be...

50 CFR 14.133 - Care in transit.

Code of Federal Regulations, 2014 CFR

2014-10-01

... knowledgeable in marine mammal care to provide for the animal's health and well-being. The shipper or... Wild Mammals and Birds to the United States Specifications for Marine Mammals (cetaceans, Sirenians, Sea Otters, Pinnipeds, and Polar Bears) § 14.133 Care in transit. (a) Any marine mammal shall be...

The sequential megafaunal collapse hypothesis: Testing with existing data

NASA Astrophysics Data System (ADS)

DeMaster, Douglas P.; Trites, Andrew W.; Clapham, Phillip; Mizroch, Sally; Wade, Paul; Small, Robert J.; Hoef, Jay Ver

2006-02-01

Springer et al. [Springer, A.M., Estes, J.A., van Vliet, G.B., Williams, T.M., Doak, D.F., Danner, E.M., Forney, K.A., Pfister, B., 2003. Sequential megafaunal collapse in the North Pacific Ocean: an ongoing legacy of industrial whaling? Proceedings of the National Academy of Sciences 100 (21), 12,223-12,228] hypothesized that great whales were an important prey resource for killer whales, and that the removal of fin and sperm whales by commercial whaling in the region of the Bering Sea/Aleutian Islands (BSAI) in the late 1960s and 1970s led to cascading trophic interactions that caused the sequential decline of populations of harbor seal, northern fur seal, Steller sea lion and northern sea otter. This hypothesis, referred to as the Sequential Megafaunal Collapse (SMC), has stirred considerable interest because of its implication for ecosystem-based management. The SMC has the following assumptions: (1) fin whales and sperm whales were important as prey species in the Bering Sea; (2) the biomass of all large whale species (i.e., North Pacific right, fin, humpback, gray, sperm, minke and bowhead whales) was in decline in the Bering Sea in the 1960s and early 1970s; and (3) pinniped declines in the 1970s and 1980s were sequential. We concluded that the available data are not consistent with the first two assumptions of the SMC. Statistical tests of the timing of the declines do not support the assumption that pinniped declines were sequential. We propose two alternative hypotheses for the declines that are more consistent with the available data. While it is plausible, from energetic arguments, for predation by killer whales to have been an important factor in the declines of one or more of the three populations of pinnipeds and the sea otter population in the BSAI region over the last 30 years, we hypothesize that the declines in pinniped populations in the BSAI can best be understood by invoking a multiple factor hypothesis that includes both bottom-up forcing (as indicated by evidence of nutritional stress in the western Steller sea lion population) and top-down forcing (e.g., predation by killer whales, mortality incidental to commercial fishing, directed harvests). Our second hypothesis is a modification of the top-down forcing mechanism (i.e., killer whale predation on one or more of the pinniped populations and the sea otter population is mediated via the recovery of the eastern North Pacific population of the gray whale). We remain skeptical about the proposed link between commercial whaling on fin and sperm whales, which ended in the mid-1960s, and the observed decline of populations of northern fur seal, harbor seal, and Steller sea lion some 15 years later.

Toxoplasma gondii infection in wild mustelids and cats across an urban-rural gradient.

PubMed

Barros, Macarena; Cabezón, Oscar; Dubey, Jitender P; Almería, Sonia; Ribas, María P; Escobar, Luis E; Ramos, Barbara; Medina-Vogel, Gonzalo

2018-01-01

The increase in human population and domestic pets, such as cats, are generating important consequences in terms of habitat loss and pathogen pollution of coastal ecosystems with potential to generate negative impacts in marine biodiversity. Toxoplasma gondii is the etiological agent of zoonotic disease toxoplasmosis, and is associated with cat abundance and anthropogenic disturbance. The presence of T. gondii oocysts in the ocean has negatively affected the health status of the threatened Southern sea otter (Enhydra lutris nereis) populations. The present study analyzed seroprevalence and presence of T. gondii DNA in American mink (Neovison vison), Southern river otters (Lontra provocax) and domestic cats (Felis silvestris catus) in four different areas in Southern Chile comprising studies in rivers and lakes in Andean foothills and mountains, marine habitat and island coastal ecosystems. Mean seroprevalence of T. gondii in the study was 64% of 151 total animals sampled: 59% of 73 American mink, 77% of 13 Southern river otters, 68% of 65 domestic cats and in two of two kodkods (Leopardus guigna). Toxoplasma gondii DNA was detected in tissues from one American mink and one Southern river otter. The present study confirms the widespread distribution of T. gondii in Southern Chile, and shows a high exposure of semiaquatic mustelids and domestic cats to the parasite. Cats and anthropogenic disturbance have a role in the maintenance of T. gondii infection in ecosystems of southern Chile.

A multi-decade time series of kelp forest community structure at San Nicolas Island, California

USGS Publications Warehouse

Lafferty, Kevin D.; Kenner, Michael C.; Estes, James A.; Tinker, M. Tim; Bodkin, James L.; Cowen, Robert K.; Harrold, Christopher; Novak, Mark; Rassweiler, Andrew; Reed, Daniel C.

2013-01-01

San Nicolas Island is surrounded by broad areas of shallow subtidal habitat, characterized by dynamic kelp forest communities that undergo dramatic and abrupt shifts in community composition. Although these reefs are fished, the physical isolation of the island means that they receive less impact from human activities than most reefs in Southern California, making San Nicolas an ideal place to evaluate alternative theories about the dynamics of these communities. Here we present monitoring data from seven sampling stations surrounding the island, including data on fish, invertebrate, and algal abundance. These data are unusual among subtidal monitoring data sets in that they combine relatively frequent sampling (twice per year) with an exceptionally long time series (since 1980). Other outstanding qualities of the data set are the high taxonomic resolution captured and the monitoring of permanent quadrats and swaths where the history of the community structure at specific locations has been recorded through time. Finally, the data span a period that includes two of the strongest ENSO events on record, a major shift in the Pacific decadal oscillation, and the reintroduction of sea otters to the island in 1987 after at least 150 years of absence. These events provide opportunities to evaluate the effects of bottom-up forcing, top-down control, and physical disturbance on shallow rocky reef communities.

50 CFR 14.132 - Food and water.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 50 Wildlife and Fisheries 1 2014-10-01 2014-10-01 false Food and water. 14.132 Section 14.132..., Sea Otters, Pinnipeds, and Polar Bears) § 14.132 Food and water. A marine mammal shall not be transported for more than a period of 36 hours without being offered suitable food unless the shipper's...

50 CFR 14.132 - Food and water.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 1 2012-10-01 2012-10-01 false Food and water. 14.132 Section 14.132..., Sea Otters, Pinnipeds, and Polar Bears) § 14.132 Food and water. A marine mammal shall not be transported for more than a period of 36 hours without being offered suitable food unless the shipper's...

50 CFR 14.132 - Food and water.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 50 Wildlife and Fisheries 1 2013-10-01 2013-10-01 false Food and water. 14.132 Section 14.132..., Sea Otters, Pinnipeds, and Polar Bears) § 14.132 Food and water. A marine mammal shall not be transported for more than a period of 36 hours without being offered suitable food unless the shipper's...

The Color of the Wind: Fables for a New Age.

ERIC Educational Resources Information Center

Nottingham, Theodore J.

This book of fables from the animal kingdom contains: "The Frog Who Knew Too Much"; "Long Tail the Lizard"; "The Otter Who Went to the Bottom of the Sea"; "The Single-Wattled Cassowary and His Lethal Toe"; "The Rebel Gerbil"; "Why Hairless Monkeys Turn Out So Bad"; and "The Eagles'…

Entering uncharted waters: Long-term dynamics of two data limited fish species, turbot and brill, in the North Sea

NASA Astrophysics Data System (ADS)

Kerby, Tina K.; Cheung, William W. L.; van Oosterhout, Cock; Engelhard, Georg H.

2013-11-01

In the North Sea, turbot (Scophthalmus maximus) and brill (Scophthalmus rhombus) represent highly valuable species in commercial fisheries. Still, available data for both species are limited, making stock assessment difficult. Long-term fisheries data have the potential to improve the understanding of stock dynamics such as long-term distribution changes or development in species' abundances. Historical British otter trawler lpue (landings-per-unit-effort) data from 1923 to 2009, and at the spatial scale of ICES rectangles, revealed that the distribution patterns of turbot and brill were different for most of the 20th century and only became similar in the recent decade. Further, between the 1920s and 1960s, turbot was commonly caught in the northern North Sea and in particular on Turbot Bank, at that time a turbot hotspot off the east coast of Scotland. Within a short time period turbot nearly disappeared from this region. Brill, in contrast, revealed a stable distribution in the southern and central North Sea with a slow expansion into the central North Sea. We used survey cpue (catch-per-unit-effort) from the International Bottom Trawl Survey (IBTS; 1970-2009) and the Beam Trawl Survey (BTS; 1985-2009), as well as British otter trawler lpue, as proxies for the abundance of adult turbot and brill. Commercial lpue suggested for brill and turbot a long-term decrease in abundance. IBTS cpue suggested an increase in abundance for turbot, but this was not confirmed by the BTS. For brill, both surveys did not show a clear trend.

Measurements of trace gases and particles in fresh and aged smoke from a chaparral fire in California

Treesearch

S. K. Akagi; J. S. Craven; J. W. Taylor; G. R. McMeeking; R. J. Yokelson; I. R. Burling; M. J. Alvarado; J. Seinfeld; H. Coe; Shawn Urbanski

2010-01-01

On November 17th 2009 we used a Twin Otter aircraft outfitted with an airborne Fourier transform infrared spectrometer (AFTIR), aerosol mass spectrometer (AMS), single particle soot photometer (SP2), nephelometer, Licor CO2 analyzer, and a chemiluminescence ozone instrument to measure the initial emissions from a 100 hectare prescribed fire in chaparral fuels on the...

Loss of genetic diversity in sea otters (Enhydra lutris) associated with the fur trade of the 18th and 19th centuries

USGS Publications Warehouse

Larson, S.; Jameson, R.; Etnier, M.; Flemings, M.; Bentzen, P.

2002-01-01

During 1969 and 1970, surveys of the endangered Yuma Clapper Rail were conducted using taped calls to elicit responses from the birds. During the two summers, more than 158 Yuma clappers were located in cattailtule marshes along the Colorado River south of Needles, California, to the International Boundary, a distance of about 240 miles. Clappers (probably of the same race) were also found in estuarian marshes of the Colorado River Delta of Mexico; in the Salton Sea; in two freshwater marsh areas near Phoenix, Arizona; and in two freshwater marshes adjacent to the lower Gila River near Tacna, Arizona.....Populations of Sonora Clapper Rails were discovered as permanent residents in five separate mangrove swamps along the west coast of Mexico in the vicinity of Kino Bay, Sonora. These observations were farther north than any heretofore reported for the race R. l. rhizophorae, and the swamps also represent the extreme northward limit of mangroves in Sonora.....During the winter, Yuma clappers did not respond to taped calls north of the International Boundary, whereas clappers along the coast of Sonora readily answered the calls during the same period of time. We conclude that most Yuma Clapper Rails migrate from their summer habitat along the Colorado River in September and do not return to the breeding areas until late April.

A List of the Marine Mammals of the World. Third Edition.

ERIC Educational Resources Information Center

Rice, Dale W.

This National Oceanic and Atmospheric Administration publication lists 116 species of living and recently extinct marine mammals of the world. Included are 36 species of Order Carnivora (polar bear, sea otter, and 34 pinnipeds); 5 species of Order Sirenia; 10 of Order Mysticeti (baleen whales); and 65 species of Order Odontoceti (tooth whales).…

75 FR 62562 - Endangered and Threatened Wildlife and Plants; Notice of Availability of Draft Recovery Plan for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-12

... plants to the point where they are again secure, self-sustaining members of their ecosystems is a primary... spills, food limitation, disturbance, bycatch in fisheries, subsistence harvest, loss of habitat, and...; (2) maintain enough sea otters to ensure that they are playing a functional role in their nearshore...

Analysis of the Meteorology Associated with the 1998 NASA Glenn Twin Otter Icing Flights

NASA Technical Reports Server (NTRS)

Bernstein, Ben C.

2000-01-01

This document contains a basic analysis of the meteorology associated with the NASA Glenn Twin Otter icing encounters between December 1997 and March 1998. The purpose of this analysis is to provide a meteorological context for the aircraft data collected during these flights. For each case, the following data elements are presented: (1) A brief overview of the Twin Otter encounter, including locations, liquid water contents, temperatures and microphysical makeup of the clouds and precipitation aloft, (2) Upper-air charts, providing hand-analyzed locations of lows, troughs, ridges, saturated/unsaturated air, temperatures, warm/cold advection, and jet streams, (3) Balloon-borne soundings, providing vertical profiles of temperature, moisture and winds, (4) Infrared and visible satellite data, providing cloud locations and cloud top temperature, (5) 3-hourly surface charts, providing hand-analyzed locations of lows, highs, fronts, precipitation (including type) and cloud cover, (6) Hourly, regional radar mosaics, providing fine resolution of the locations of precipitation (including intensity and type), pilot reports of icing (including intensity and type), surface observations of precipitation type and Twin Otter tracks for a one hour window centered on the time of the radar data, and (7) Hourly plots of icing pilot reports, providing the icing intensity, icing type, icing altitudes and aircraft type. Outages occurred in nearly every dataset at some point. All relevant data that was available is presented here. All times are in UTC and all heights are in feet above mean sea level (MSL).

Concentration and retention of Toxoplasma gondii surrogates from seawater by red abalone (Haliotis rufescens).

PubMed

Schott, Kristen C; Krusor, Colin; Tinker, M Tim; Moore, James; Conrad, Patricia A; Shapiro, Karen

2016-11-01

Small marine snails and abalone have been identified as high- and low-risk prey items, respectively, for exposure of threatened southern sea otters to Toxoplasma gondii, a zoonotic parasite that can cause fatal encephalitis in animals and humans. While recent work has characterized snails as paratenic hosts for T. gondii, the ability of abalone to vector the parasite has not been evaluated. To further elucidate why abalone predation may be protective against T. gondii exposure, this study aimed to determine whether: (1) abalone are physiologically capable of acquiring T. gondii; and (2) abalone and snails differ in their ability to concentrate and retain the parasite. Abalone were exposed to T. gondii surrogate microspheres for 24 h, and fecal samples were examined for 2 weeks following exposure. Concentration of surrogates was 2-3 orders of magnitude greater in abalone feces than in the spiked seawater, and excretion of surrogates continued for 14 days post-exposure. These results indicate that, physiologically, abalone and snails can equally vector T. gondii as paratenic hosts. Reduced risk of T. gondii infection in abalone-specializing otters may therefore result from abalone's high nutritional value, which implies otters must consume fewer animals to meet their caloric needs.

78 FR 23284 - Marine Mammal Protection Act; Draft Revised Stock Assessment Reports for the Pacific Walrus and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-18

.... We now make the SARs available for public review and comment. DATES: Comments must be received by... NMFS to review the SARs (a) At least annually for stocks that are specified as strategic stocks, (b) at... determined. SARs for the Southwest, Southcentral, and Southeast stocks of northern sea otters were last...

75 FR 63850 - Proposed Information Collection; OMB Control Number 1018-0066; Marine Mammal Tagging, Marking...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-18

.... SUMMARY: We (U.S. Fish and Wildlife Service) will ask the Office of Management and Budget (OMB) to approve.... Abstract Under section 101(b) of the Marine Mammal Protection Act of 1972 (MMPA), as amended (16 U.S.C... Native subsistence and handicraft harvest and on the biology of polar bear, northern sea otter, and...

Population demographics, survival, and reporduction: Alaska sea otter research

USGS Publications Warehouse

Monson, Daniel H.; Bodkin, James L.; Doak, D.F.; Estes, James A.; Tinker, M.T.; Siniff, D.B.; Maldini, Daniela; Calkins, Donald; Atkinson, Shannon; Meehan, Rosa

2004-01-01

The fundamental force behind population change is the balance between age-specific survival and reproductive rates. Thus, understanding population demographics is crucial when trying to interpret trends in population change over time. For many species, demographic rates change as the population’s status (i.e., relative to prey resources) varies. Indices of body condition indicative of individual energy reserves can be a useful gauge of population status. Integrated studies designed to measure (1) population trends; (2) current population status; and (3) demographic rates will provide the most complete picture of the factors driving observed population changes. In particular, estimates of age specific survival and reproduction in conjunction with measures of population change can be integrated into population matrix models useful in explaining observed trends. We focus here on the methods used to measure demographic rates in sea otters, and note the importance of comparable methods between studies. Next, we review the current knowledge of the influence of population status on demographic parameters. We end with examples of the power of matrix modeling as a tool to integrate various types of demographic information for detecting otherwise hard to detect changes in demographic parameters.

Population demographics and genetic diversity in remnant and translocated populations of sea otters

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.; Cronin, M.A.; Scribner, K.T.

1999-01-01

The effects of small population size on genetic diversity and subsequent population recovery are theoretically predicted, but few empirical data are available to describe those relations. We use data from four remnant and three translocated sea otter (Enhydra lutris) populations to examine relations among magnitude and duration of minimum population size, population growth rates, and genetic variation. Metochondrial (mt)DNA haplotype diversity was correlated with the number of years at minimum population size (r = -0.741, p = 0.038) and minimum population size (r = 0.709, p = 0.054). We found no relation between population growth and haplotype diversity, altough growth was significantly greater in translocated than in remnant populations. Haplotype diversity in populations established from two sources was higher than in a population established from a single source and was higher than in the respective source populations. Haplotype frequencies in translocated populations of founding sizes of 4 and 28 differed from expected, indicating genetic drift and differential reproduction between source populations, whereas haplotype frequencies in a translocated population with a founding size of 150 did not. Relations between population demographics and genetic characteristics suggest that genetic sampling of source and translocated populations can provide valuable inferences about translocations.

Habitat compression and expansion of sea urchins in response to changing climate conditions on the California continental shelf and slope (1994-2013)

NASA Astrophysics Data System (ADS)

Sato, Kirk N.; Levin, Lisa A.; Schiff, Kenneth

2017-03-01

Echinoid sea urchins with distributions along the continental shelf and slope of the eastern Pacific often dominate the megafauna community. This occurs despite their exposure to naturally low dissolved oxygen (DO) waters (<60 μmol kg-1) associated with the Oxygen Limited Zone and low-pH waters undersaturated with respect to calcium carbonate (ΩCaCO3<1). Here we present vertical depth distribution and density analyses of historical otter trawl data collected in the Southern California Bight (SCB) from 1994 to 2013 to address the question: Do changes in echinoid density and species' depth distributions along the continental margin in the SCB reflect observed secular or interannual changes in climate? Deep-dwelling burrowing urchins (Brissopsis pacifica, Brisaster spp. and Spatangus californicus), which are adapted to low-DO, low-pH conditions appeared to have expanded their vertical distributions and populations upslope over the past decade (2003-2013), and densities of the deep pink urchin, Strongylocentrotus fragilis, increased significantly in the upper 500 m of the SCB. Conversely, the shallower urchin, Lytechinus pictus, exhibited depth shoaling and density decreases within the upper 200 m of the SCB from 1994 to 2013. Oxygen and pH in the SCB also vary inter-annually due to varying strengths of the El Niño Southern Oscillation (ENSO). Changes in depth distributions and densities were correlated with bi-monthly ENSO climate indices in the region. Our results suggest that both a secular trend in ocean deoxygenation and acidification and varying strength of ENSO may be linked to echinoid species distributions and densities, creating habitat compression in some and habitat expansion in others. Potential life-history mechanisms underlying depth and density changes observed over these time periods include migration, mortality, and recruitment. These types of analyses are needed for a broad suite of benthic species in order to identify and manage climate-sensitive species on the margin.

A bill to amend the Marine Mammal Protection Act of 1972 to allow the transport, purchase, and sale of pelts of, and handicrafts, garments, and art produced from, Southcentral and Southeast Alaska northern sea otters that are taken for subsistence purposes.

THOMAS, 112th Congress

Sen. Murkowski, Lisa [R-AK

2011-07-29

Senate - 07/29/2011 Read twice and referred to the Committee on Commerce, Science, and Transportation. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Prevalence of algal toxins in Alaskan marine mammals foraging in a changing arctic and subarctic environment.

PubMed

Lefebvre, Kathi A; Quakenbush, Lori; Frame, Elizabeth; Huntington, Kathy Burek; Sheffield, Gay; Stimmelmayr, Raphaela; Bryan, Anna; Kendrick, Preston; Ziel, Heather; Goldstein, Tracey; Snyder, Jonathan A; Gelatt, Tom; Gulland, Frances; Dickerson, Bobette; Gill, Verena

2016-05-01

Current climate trends resulting in rapid declines in sea ice and increasing water temperatures are likely to expand the northern geographic range and duration of favorable conditions for harmful algal blooms (HABs), making algal toxins a growing concern in Alaskan marine food webs. Two of the most common HAB toxins along the west coast of North America are the neurotoxins domoic acid (DA) and saxitoxin (STX). Over the last 20 years, DA toxicosis has caused significant illness and mortality in marine mammals along the west coast of the USA, but has not been reported to impact marine mammals foraging in Alaskan waters. Saxitoxin, the most potent of the paralytic shellfish poisoning toxins, has been well-documented in shellfish in the Aleutians and Gulf of Alaska for decades and associated with human illnesses and deaths due to consumption of toxic clams. There is little information regarding exposure of Alaskan marine mammals. Here, the spatial patterns and prevalence of DA and STX exposure in Alaskan marine mammals are documented in order to assess health risks to northern populations including those species that are important to the nutritional, cultural, and economic well-being of Alaskan coastal communities. In this study, 905 marine mammals from 13 species were sampled including; humpback whales, bowhead whales, beluga whales, harbor porpoises, northern fur seals, Steller sea lions, harbor seals, ringed seals, bearded seals, spotted seals, ribbon seals, Pacific walruses, and northern sea otters. Domoic acid was detected in all 13 species examined and had the greatest prevalence in bowhead whales (68%) and harbor seals (67%). Saxitoxin was detected in 10 of the 13 species, with the highest prevalence in humpback whales (50%) and bowhead whales (32%). Pacific walruses contained the highest concentrations of both STX and DA, with DA concentrations similar to those detected in California sea lions exhibiting clinical signs of DA toxicosis (seizures) off the coast of Central California, USA. Forty-six individual marine mammals contained detectable concentrations of both toxins emphasizing the potential for combined exposure risks. Additionally, fetuses from a beluga whale, a harbor porpoise and a Steller sea lion contained detectable concentrations of DA documenting maternal toxin transfer in these species. These results provide evidence that HAB toxins are present throughout Alaska waters at levels high enough to be detected in marine mammals and have the potential to impact marine mammal health in the Arctic marine environment. Published by Elsevier B.V.

Aquatic polymers can drive pathogen transmission in coastal ecosystems

PubMed Central

Shapiro, Karen; Krusor, Colin; Mazzillo, Fernanda F. M.; Conrad, Patricia A.; Largier, John L.; Mazet, Jonna A. K.; Silver, Mary W.

2014-01-01

Gelatinous polymers including extracellular polymeric substances (EPSs) are fundamental to biophysical processes in aquatic habitats, including mediating aggregation processes and functioning as the matrix of biofilms. Yet insight into the impact of these sticky molecules on the environmental transmission of pathogens in the ocean is limited. We used the zoonotic parasite Toxoplasma gondii as a model to evaluate polymer-mediated mechanisms that promote transmission of terrestrially derived pathogens to marine fauna and humans. We show that transparent exopolymer particles, a particulate form of EPS, enhance T. gondii association with marine aggregates, material consumed by organisms otherwise unable to access micrometre-sized particles. Adhesion to EPS biofilms on macroalgae also captures T. gondii from the water, enabling uptake of pathogens by invertebrates that feed on kelp surfaces. We demonstrate the acquisition, concentration and retention of T. gondii by kelp-grazing snails, which can transmit T. gondii to threatened California sea otters. Results highlight novel mechanisms whereby aquatic polymers facilitate incorporation of pathogens into food webs via association with particle aggregates and biofilms. Identifying the critical role of invisible polymers in transmission of pathogens in the ocean represents a fundamental advance in understanding and mitigating the health impacts of coastal habitat pollution with contaminated runoff. PMID:25297861

Concentration and retention of Toxoplasma gondii surrogates from seawater by red abalone (Haliotis rufescens)

USGS Publications Warehouse

Schott, Kristen C; Krusor, Colin; Tinker, M. Tim; Moore, James G.; Conrad, Patricia A.; Shapiro, Karen

2016-01-01

Small marine snails and abalone have been identified as high- and low-risk prey items, respectively, for exposure of threatened southern sea otters to Toxoplasma gondii, a zoonotic parasite that can cause fatal encephalitis in animals and humans. While recent work has characterized snails as paratenic hosts for T. gondii, the ability of abalone to vector the parasite has not been evaluated. To further elucidate why abalone predation may be protective against T. gondii exposure, this study aimed to determine whether: (1) abalone are physiologically capable of acquiring T. gondii; and (2) abalone and snails differ in their ability to concentrate and retain the parasite. Abalone were exposed to T. gondii surrogate microspheres for 24 h, and fecal samples were examined for 2 weeks following exposure. Concentration of surrogates was 2–3 orders of magnitude greater in abalone feces than in the spiked seawater, and excretion of surrogates continued for 14 days post-exposure. These results indicate that, physiologically, abalone and snails can equally vector T. gondii as paratenic hosts. Reduced risk of T. gondii infection in abalone-specializing otters may therefore result from abalone's high nutritional value, which implies otters must consume fewer animals to meet their caloric needs.

ASSOCIATION BETWEEN POSITIVE CANINE HEARTWORM (DIROFILARIA IMMITIS) ANTIGEN RESULTS AND PRESENCE OF ACANTHOCHEILONEMA ODENDHALI MICROFILARIA IN CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS).

PubMed

Krucik, David D R; Van Bonn, William; Johnson, Shawn P

2016-03-01

This study establishes a relationship between positive canine heartworm (Dirofilaria immitis) test results frequently observed in California sea lions (Zalophus californianus) and infection with the filarid nematode Acanthocheilonema odendhali. Four commercially available canine heartworm antigen tests were evaluated for cross-reaction with A. odendhali in California sea lions. Sera were tested from fifteen California sea lions with A. odendhali-associated microfilaremia, confirmed by blood smear, and with no evidence of D. immitis infection at necropsy. Ninety-five percent of tests were falsely positive for D. immitis. This study also determined that the prevalence of A. odendhali infection in stranded California sea lions from central California is approximately 23% by comparing the number of findings of mircofilaremia to the total number of California sea lions sampled at The Marine Mammal Center between 2005 and 2011, inclusive. Acanthocheilonema odenhali microfilaremia in California sea lions is likely to cross-react with canine heartworm antigen tests, and clinicians should interpret results with caution.

Limited genetic diversity among Sarcocystis neurona strains infecting southern sea otters precludes distinction between marine and terrestrial isolates

PubMed Central

Wendte, J.M.; Miller, M.A.; Nandra, A.K.; Peat, S.M.; Crosbie, P.R.; Conrad, P.A.; Grigg, M.E.

2010-01-01

Sarcocystis neurona is an apicomplexan parasite identified as a cause of fatal neurological disease in the threatened southern sea otter (Enhydra lutris nereis). In an effort to characterize virulent S. neurona strains circulating in the marine ecosystem, this study developed a range of markers relevant for molecular genotyping. Highly conserved sequences within the 18S ribosomal gene array, the plastid-encoded RNA polymerase (RPOb) and the cytochrome c oxidase subunit 1 mitochondrial gene (CO1) were assessed for their ability to distinguish isolates at the genus and species level. For within-species comparisons, five surface antigens (SnSAG1-SnSAG5) and one high resolution microsatellite marker (Sn9) were developed as genotyping markers to evaluate intra-strain diversity. Molecular analysis at multiple loci revealed insufficient genetic diversity to distinguish terrestrial isolates from strains infecting marine mammals. Furthermore, SnSAG specific primers applied against DNA from the closely related species, Sarcocystis falcatula, lead to the discovery of highly similar orthologs to SnSAG2, 3, and 4, calling into question the specificity of diagnostic tests based on these antigens. The results of this study suggest a population genetic structure for S. neurona similar to that reported for the related parasite, Toxoplasma gondii, dominated by a limited number of successful genotypes. PMID:20071081

Trawl disturbance on benthic communities: chronic effects and experimental predictions.

PubMed

Hinz, Hilmar; Prieto, Virginia; Kaiser, Michel J

2009-04-01

Bottom trawling has widespread impacts on benthic communities and habitats. While the direct impacts of trawl disturbances on benthic communities have been extensively studied, the consequences from long-term chronic disturbances are less well understood. The response of benthic macrofauna to chronic otter-trawl disturbance from a Nephrops norvegicus (Norway lobster) fishery was investigated along a gradient of fishing intensity over a muddy fishing ground in the northeastern Irish Sea. Chronic otter trawling had a significant, negative effect on benthic infauna abundance, biomass, and species richness. Benthic epifauna abundance and species richness also showed a significant, negative response, while no such effect was evident for epibenthic biomass. Furthermore, chronic trawl disturbance led to clear changes in community composition of benthic infauna and epifauna. The results presented indicate that otter-trawl impacts are cumulative and can lead to profound changes in benthic communities, which may have far-reaching implications for the integrity of marine food webs. Studies investigating the short-term effects of fishing manipulations previously concluded that otter trawling on muddy substrates had only modest effects on the benthic biota. Hence, the results presented by this study highlight that data from experimental studies can not be readily extrapolated to an ecosystem level and that subtle cumulative effects may only become apparent when fishing disturbances are examined over larger spatial and temporal scales. Furthermore, this study shows that data on chronic effects of bottom trawling on the benthos will be vital in informing the recently advocated move toward an ecosystem approach in fisheries management. As bottom-trawl fisheries are expanding into ever deeper muddy habitats, the results presented here are an important step toward understanding the global ecosystem effects of bottom trawling.

The relationship between sea surface temperature and chlorophyll concentration of phytoplanktons in the Black Sea using remote sensing techniques.

PubMed

Kavak, Mehmet Tahir; Karadogan, Sabri

2012-04-01

Present work investigated the relationship between Chlorophyll (Chl), of phytoplankton biomass, and sea surface temperature (SST) of the Black Sea, using Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Advanced Very High Resolution Radiometer (AVHRR) satellite imagery. Satellite derived data could provide information on the amount of sea life present (Brown algae, called kelp, proliferate, supporting new species of sea life, including otters, fish, and various invertebrates) in a given area throughout the world. SST from AVHRR from 1993 to 2008 showed seasonal, annual and interannual variability of temperature, monthly variability Chl from SeaWiFS from 1997 to 2009 has also been investigated. Chl showed two high peaks for the year 1999 and 2008. The correlation between SST and Chl for the same time has been found to be 60%. Correlation was significant at p<0.05. The information could also be useful in connection with studies of global changes in temperature and what effect they could have on the total abundance of marine life.

Spatio-temporal variations in age structures of a partially re-established population of northern river otters (Lontra canadensis)

USGS Publications Warehouse

Barrett, Dominic A.; Leslie, David M.

2012-01-01

Examination of age structures and sex ratios is useful in the management of northern river otters (Lontra canadensis) and other furbearers. Reintroductions and subsequent recolonizations of river otters have been well documented, but changes in demographics between expanding and established populations have not been observed. As a result of reintroduction efforts, immigration from Arkansas and northeastern Texas, and other efforts, river otters have become partially reestablished throughout eastern and central Oklahoma. Our objective was to examine age structures of river otters in Oklahoma and identify trends that relate to space (watersheds, county) and time (USDA Animal and Plant Health Inspection Service county trapping records). We predicted that river otters in western areas of the state were younger than river otters occurring farther east. From 2005–2007, we obtained salvaged river otter carcasses from federal and state agencies, and we live-captured other river otters using leg hold traps. Seventy-two river otters were sampled. Overall, sex ratios were skewed toward females (1F∶0.8M), but they did not differ among spatiotemporal scales examined. Teeth were removed from salvaged and live-captured river otters (n  =  63) for aging. One-year old river otters represented the largest age class (30.2%). Proportion of juveniles (<1 y old) in Oklahoma (19.0%) was less than other states. Mean age of river otters decreased from east-to-west in the Arkansas River and its tributaries. Mean age of river otters differed between the Canadian River Watershed (0.8 y) and the Arkansas River Watershed (2.9 y) and the Canadian River Watershed and the Red River Watershed (2.4 y). Proportion of juveniles did not differ among spatiotemporal scales examined. Similar to age structure variations in other mammalian carnivores, colonizing or growing western populations of river otters in Oklahoma contained younger ages than more established eastern populations.

The Microphysics of Antarctic Clouds - Part one Observations.

NASA Astrophysics Data System (ADS)

Lachlan-Cope, Tom; Listowski, Constantino; O'Shea, Sebastian; Bower, Keith

2016-04-01

During the Antarctic summer of 2010 and 2011 in-situ measurements of clouds were made over the Antarctic Peninsula and in 2015 similar measurements were made over the eastern Weddell Sea using the British Antarctic Surveys instrumented Twin Otter aircraft. This paper contrasts the clouds found on either side of the Antarctic Peninsula with the clouds over the eastern Weddell Sea, paying particular attention to the total number of ice and water particles found in the clouds. The differences found between the clouds are considered in relation to the sources of cloud condensation nuclei and ice nuclei that are expected to be active in the different cases. In particular it was found that the number of ice nuclei was very low over the Weddell Sea when compared to other regions.

At-vessel mortality of skates (Rajidae) taken in coastal fisheries and evidence of longer-term survival.

PubMed

Ellis, J R; Burt, G J; Grilli, G; McCully Phillips, S R; Catchpole, T L; Maxwell, D L

2018-06-01

Data on the vigour and at-vessel mortality (AVM) of 6798 skates (comprising Raja clavata n = 6295; R. brachyura n = 208; R. undulata n = 185, R. montagui n = 98 and R. microocellata n = 12) captured by commercial fishing vessels in the inshore waters of the southern North Sea and English Channel were recorded. AVM in longline fisheries averaged 0·44% across five vessels (0-1·47%), although skates were usually unhooked manually and did not usually pass through a bait-stripper. AVM in otter trawls averaged 0·76% (0-2·35%), from four vessels fishing with tow durations of <1·5 h (southern North Sea) or 1-4 h (English Channel). No AVM was noted for skates taken as a by-catch in drift trammel nets (soak times <4 h). Anchored tangle nets resulted in an overall AVM of 2·0-2·7%, but increased from 1·47% (13-28 h soak time) to 6·16% (42-53 h soak time). There were significant differences in the vigour of skates between gears, with R. clavata caught by longline and tangle nets in better condition than those captured by otter trawl or drift trammel net. Similarly, R. undulata caught by tangle net were in better condition than those caught by otter trawl. The vigour of R. undulata was also found to be higher than other skate species for both trawl and tangle net. In total, 5283 skates were tagged with Petersen discs and released, with recapture rates for the various combinations of vessel and gear ranging up to 24·8% for R. clavata. Whilst confirming a degree of post-release survival, quantitative estimates of post-release mortality for skates remain unknown. © 2018 Crown Copyright. Journal of Fish Biology © 2018 The Fisheries Society of the British Isles.

Oil Spills and Marine Mammals in British Columbia, Canada: Development and Application of a Risk-Based Conceptual Framework.

PubMed

Jarvela Rosenberger, Adrianne L; MacDuffee, Misty; Rosenberger, Andrew G J; Ross, Peter S

2017-07-01

Marine mammals are inherently vulnerable to oil spills. We developed a conceptual framework to evaluate the impacts of potential oil exposure on marine mammals and applied it to 21 species inhabiting coastal British Columbia (BC), Canada. Oil spill vulnerability was determined by examining both the likelihood of species-specific (individual) oil exposure and the consequent likelihood of population-level effects. Oil exposure pathways, ecology, and physiological characteristics were first used to assign species-specific vulnerability rankings. Baleen whales were found to be highly vulnerable due to blowhole breathing, surface filter feeding, and invertebrate prey. Sea otters (Enhydra lutris) were ranked as highly vulnerable due to their time spent at the ocean surface, dense pelage, and benthic feeding techniques. Species-specific vulnerabilities were considered to estimate the likelihood of population-level effects occurring after oil exposure. Killer whale (Orcinus orca) populations were deemed at highest risk due to small population sizes, complex social structure, long lives, slow reproductive turnover, and dietary specialization. Finally, we related the species-specific and population-level vulnerabilities. In BC, vulnerability was deemed highest for Northern and Southern Resident killer whales and sea otters, followed by Bigg's killer whales and Steller sea lions (Eumetopias jubatus). Our findings challenge the typical "indicator species" approach routinely used and underscore the need to examine marine mammals at a species and population level for risk-based oil spill predictions. This conceptual framework can be combined with spill probabilities and volumes to develop more robust risk assessments and may be applied elsewhere to identify vulnerability themes for marine mammals.

Sporulation and survival of Toxoplasma gondii oocysts in seawater

USGS Publications Warehouse

Lindsay, D.S.; Collins, M.V.; Mitchell, S.M.; Cole, Rebecca A.; Flick, G.J.; Wetch, C.N.; Lindquist, A.; Dubey, J.P.

2003-01-01

We have been collaborating since 1992 in studies on southern sea otters (Enhdyra lutris nereis) as part of a program to define factors, which may be responsible for limiting the growth of the southern sea otter population. We previously demonstrated Toxoplasma gondii in sea otiers. We postulated that cat feces containing oocysts could be entering the marine environment through storm run-off or through municipal sewage since cat feces are often disposed down toilets by cat owners. The present study examined the sporulation of T. gondiioocysts in seawater and the survival of sporulated oocysts in seawater. Unsporulated oocysts were placed in 1.5 ppt artificial seawater, 32 ppt artificial seawater or 2% sulfuric acid (positive control) at 24 C in an incubator. Samples were examined daily for 3 days and development monitored by counting 100 oocysts from each sample. From 75 to 80% of the oocysts were sporulated by 3 days post-inoculation under all treatment conditions. Groups of 2 mice were fed 10,000 oocysts each from each of the 3 treatment groups. All inoculated mice developed toxoplasmosis indicating that oocysts were capable of sporulating in seawater. Survival of sporulated oocysts was examined by placing sporulated T. gondii oocysts in 15 ppt seawater at room temperature 22–24 C (RT) or in a refrigerator kept at 4 C. Mice fed oocysts that had been stored at 4C or RT for 6 months became infected. These results indicate that T. gondii oocysts can sporulate and remain viable in seawater for several months.

Assessment of injury to river otters in Prince William Sound, Alaska, following the Exxon Valdez oil spill. Terrestrial mammal study number 3. Exxon Valdez oil spill state/federal natural resource damage assessment final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faro, J.B.; Bowyer, R.T.; Testa, J.W.

1994-03-01

River otters (Lutra canadensis) were killed by direct effects of the Exxon Valdez oil spill, but the magnitude of that loss is unknown due to lack of pre-spill data. A time lag in spill effects is reflected by the reduction in species richness and diversity in the summer diets of otters in oiled areas between 1989 and 1990. Otters from oiled areas had higher haptoglobin levels in both 1990 and 1991. Male otters captured in oiled areas in 1990 had significantly lower body mass than otters from nonoiled areas. Otters from oiled areas had home ranges that were twice asmore » large as those from a non-spill area. Differences in rates of fecal deposition between oiled and nonoiled latrine sites in 1989 suggest otters used heavily oiled areas less often. Otters avoided shorelines with shallow slopes on the oiled area, whereas they strongly preferred these slopes on nonoiled sites, suggesting that otters lost habitat as a result of the spill.« less

Uncinariasis in northern fur seal and California sea lion pups from California.

PubMed

Lyons, E T; DeLong, R L; Melin, S R; Tolliver, S C

1997-10-01

Northern fur seal (Callorhinus ursinus) (n = 25) and California sea lion (Zalophus californianus) (n = 53) pups, found dead on rookeries on San Miguel Island (California, USA), were examined for adult Uncinaria spp. Prevalence of these nematodes was 96% in fur seal pups and 100% in sea lion pups. Mean intensity of Uncinaria spp. per infected pup was 643 in fur seals and 1,284 in sea lions. Eggs of Uncinaria spp. from dead sea lion pups underwent embryonation in an incubator; development to the free-living third stage larva occurred within the egg. This study provided some specific information on hookworm infections in northern fur seal and California sea lion pups on San Miguel Island. High prevalence rate of Uncinaria spp. in both species of pinnipeds was documented and much higher numbers (2X) of hookworms were present in sea lion than fur seal pups.

Monterey Bay Aquarium Volunteer Guide Scheduling Analysis

DTIC Science & Technology

2014-12-01

wetlands/aviary 1 24 splash zone—rocky shore, coral reef kingdom 8 play your part 25 sandy seafloor 9 wetlands/aviary 2 26 octopus/deep reef 10...greeter (main entry) 27 coastal stream/ waves and tides (rocky shore) 11 marine mammal cart 28 enchanted kelp forest 12 today on the bay 1 29...sea otter exhibit 13 kelp touch pool 4 30 boiler/ cannery row exhibit 14 touch pool 3 31 shale reef /wharf 15 tentacles 32 jellies experience 16

Limited genetic diversity among Sarcocystis neurona strains infecting southern sea otters precludes distinction between marine and terrestrial isolates.

PubMed

Wendte, J M; Miller, M A; Nandra, A K; Peat, S M; Crosbie, P R; Conrad, P A; Grigg, M E

2010-04-19

Sarcocystis neurona is an apicomplexan parasite identified as a cause of fatal neurological disease in the threatened southern sea otter (Enhydra lutris nereis). In an effort to characterize virulent S. neurona strains circulating in the marine ecosystem, this study developed a range of markers relevant for molecular genotyping. Highly conserved sequences within the 18S ribosomal gene array, the plastid-encoded RNA polymerase (RPOb) and the cytochrome c oxidase subunit 1 mitochondrial gene (CO1) were assessed for their ability to distinguish isolates at the genus and species level. For within-species comparisons, five surface antigens (SnSAG1-SnSAG5) and one high resolution microsatellite marker (Sn9) were developed as genotyping markers to evaluate intra-strain diversity. Molecular analysis at multiple loci revealed insufficient genetic diversity to distinguish terrestrial isolates from strains infecting marine mammals. Furthermore, SnSAG specific primers applied against DNA from the closely related species, Sarcocystis falcatula, lead to the discovery of highly similar orthologs to SnSAG2, 3, and 4, calling into question the specificity of diagnostic tests based on these antigens. The results of this study suggest a population genetic structure for S. neurona similar to that reported for the related parasite, Toxoplasma gondii, dominated by a limited number of successful genotypes. Published by Elsevier B.V.

Food limitation leads to behavioral diversification and dietary specialization in sea otters

USGS Publications Warehouse

Tinker, M.T.; Bentall, G.; Estes, J.A.

2008-01-01

Dietary diversity often varies inversely with prey resource abundance. This pattern, although typically measured at the population level, is usually assumed to also characterize the behavior of individual animals within the population. However, the pattern might also be produced by changes in the degree of variation among individuals. Here we report on dietary and associated behavioral changes that occurred with the experimental translocation of sea otters from a food-poor to a food-rich environment. Although the diets of all individuals were broadly similar in the food-rich environment, a behaviorally based dietary polymorphism existed in the food-poor environment. Higher dietary diversity under low resource abundance was largely driven by greater variation among individuals. We further show that the dietary polymorphism in the food-poor environment included a broad suite of correlated behavioral variables and that the individuals that comprised specific behavioral clusters benefited from improved foraging efficiency on their individually preferred prey. Our findings add to the growing list of examples of extreme individuality in behavior and prey choice within populations and suggest that this phenomenon can emerge as a behavioral manifestation of increased population density. Individuality in foraging behavior adds complexity to both the fitness consequences of prey selection and food web dynamics, and it may figure prominently as a diversifying process over evolutionary timescales. ?? 2008 by The National Academy of Sciences of the USA.

Future loss of Arctic sea-ice cover could drive a substantial decrease in California's rainfall.

PubMed

Cvijanovic, Ivana; Santer, Benjamin D; Bonfils, Céline; Lucas, Donald D; Chiang, John C H; Zimmerman, Susan

2017-12-05

From 2012 to 2016, California experienced one of the worst droughts since the start of observational records. As in previous dry periods, precipitation-inducing winter storms were steered away from California by a persistent atmospheric ridging system in the North Pacific. Here we identify a new link between Arctic sea-ice loss and the North Pacific geopotential ridge development. In a two-step teleconnection, sea-ice changes lead to reorganization of tropical convection that in turn triggers an anticyclonic response over the North Pacific, resulting in significant drying over California. These findings suggest that the ability of climate models to accurately estimate future precipitation changes over California is also linked to the fidelity with which future sea-ice changes are simulated. We conclude that sea-ice loss of the magnitude expected in the next decades could substantially impact California's precipitation, thus highlighting another mechanism by which human-caused climate change could exacerbate future California droughts.

A New Perspective on the Foraging Ecology of Apex Predators in the California Current: Results from a Fully Coupled Ecosystem Model

NASA Astrophysics Data System (ADS)

Fiechter, J.; Huckstadt, L. A.; Rose, K.; Costa, D. P.; Curchitser, E. N.; Hedstrom, K.; Edwards, C. A.; Moore, A. M.

2016-02-01

Results from a fully coupled end-to-end ecosystem model for the California Current Large Marine Ecosystem are used to describe the impact of environmental variability on the foraging ecology of its most abundant apex predator, California sea lions (Zalophus californianus). The ecosystem model consists of a biogeochemical submodel embedded in a regional ocean circulation submodel, and both coupled with a multi-species individual-based submodel for forage fish (sardine and anchovy) and California sea lions. For sea lions, bioenergetics and behavioral attributes are specified using available TOPP (Tagging Of Pacific Predators) data on their foraging patterns and diet in the California Current. Sardine and anchovy are explicitly included in the model as they represent important prey sources for California sea lions and exhibit significant interannual and decadal variability in population abundances. Output from a 20-year run (1989-2008) of the model demonstrates how different physical and biological processes control habitat utilization and foraging success of California sea lions on interannual time scales. A principal component analysis of sea lion foraging patterns indicates that the first mode of variability is alongshore and tied to sardine availability, while the second mode is cross-shore and associated with coastal upwelling intensity (a behavior consistent with male sea lion tracking data collected in 2004 vs. 2005). The results also illustrate how variability in environmental conditions and forage fish distribution affects sea lions feeding success. While specifically focusing on the foraging ecology of sea lions, our modeling framework has the ability to provide new and unique perspectives on trophic interactions in the California Current, or other regions where similar end-to-end ecosystem models may be implemented.

A survey of abnormal repetitive behaviors in North American river otters housed in zoos.

PubMed

Morabito, Paige; Bashaw, Meredith J

2012-01-01

Stereotypic behaviors, indicating poor welfare and studied in a variety of species (especially carnivores), appear related to characteristics of current and past environments. Although North American river otters (Lontra canadensis) often develop abnormal, repetitive, possibly stereotypic behaviors, no published reports describe otter housing and management or characterize how these variables relate to abnormal repetitive behavior (ARB) occurrence. The first author developed surveys to gather data on housing, individual history, management, and the prevalence of ARBs in otters housed in facilities accredited by the Association of Zoos and Aquariums. Consistent with anecdotal evidence that otters are prone to ARBs, 46% of river otters in the study exhibit them. ARBs were mostly locomotor and often preceded feeding. Exhibits where otters were fed and trained housed a greater percentage of nonhuman animals with ARBs. This study supports the Tarou, Bloomsmith, and Maple (2005) report that more hands-on management is associated with higher levels of ARBs because management efforts are only for animals with ARBs. Escape motivation, breeding season, feeding cues, and ability to forage may affect ARBs in river otters and should be investigated.

Phylogeography of the smooth-coated otter (Lutrogale perspicillata): distinct evolutionary lineages and hybridization with the Asian small-clawed otter (Aonyx cinereus).

PubMed

Moretti, Beatrice; Al-Sheikhly, Omar F; Guerrini, Monica; Theng, Meryl; Gupta, Brij K; Haba, Mukhtar K; Khan, Waseem A; Khan, Aleem A; Barbanera, Filippo

2017-01-27

We investigated the phylogeography of the smooth-coated otter (Lutrogale perspicillata) to determine its spatial genetic structure for aiding an adaptive conservation management of the species. Fifty-eight modern and 11 archival (dated 1882-1970) otters sampled from Iraq to Malaysian Borneo were genotyped (mtDNA Cytochrome-b, 10 microsatellite DNA loci). Moreover, 16 Aonyx cinereus (Asian small-clawed otter) and seven Lutra lutra (Eurasian otter) were sequenced to increase information available for phylogenetic reconstructions. As reported in previous studies, we found that L. perspicillata, A. cinereus and A. capensis (African clawless otter) grouped in a clade sister to the genus Lutra, with L. perspicillata and A. cinereus being reciprocally monophyletic. Within L. perspicillata, we uncovered three Evolutionarily Significant Units and proved that L. p. maxwelli is not only endemic to Iraq but also the most recent subspecies. We suggest a revision of the distribution range limits of easternmost L. perspicillata subspecies. We show that smooth-coated otters in Singapore are L. perspicillata x A. cinereus hybrids with A. cinereus mtDNA, the first reported case of hybridization in the wild among otters. This result also provides evidence supporting the inclusion of L. perspicillata and A. cinereus in the genus Amblonyx, thus avoiding the paraphyly of the genus Aonyx.

Toxoplasma gondii, Neospora caninum, Sarcocystis neurona, and Sarcocystis canis-like infections in marine mammals

USGS Publications Warehouse

Dubey, J.P.; Zarnke, R.; Thomas, N.J.; Wong, S.K.; Vanbonn, W.; Briggs, M.; Davis, J.W.; Ewing, R.; Mense, M.; Kwok, O.C.H.; Romand, S.; Thulliez, P.

2003-01-01

Toxoplasma gondii, Neospora caninum, Sarcocystis neurona, and S. canis are related protozoans that can cause mortality in many species of domestic and wild animals. Recently, T. gondii and S. neurona were recognized to cause encephalitis in marine mammals. As yet, there is no report of natural exposure of N. caninum in marine mammals. In the present study, antibodies to T. gondii and N. caninum were assayed in sera of several species of marine mammals. For T. gondii, sera were diluted 1:25, 1:50, and 1:500 and assayed in the T. gondii modified agglutination test (MAT). Antibodies (MAT a?Y1:25) to T. gondii were found in 89 of 115 (77%) dead, and 18 of 30 (60%) apparently healthy sea otters (Enhydra lutris), 51 of 311 (16%) Pacific harbor seals (Phoca vitulina), 19 of 45 (42%) sea lions (Zalophus californianus), 5 of 32 (16%) ringed seals (Phoca hispida), 4 of 8 (50%) bearded seals (Erignathus barbatus), 1 of 9 (11.1%) spotted seals (Phoca largha), 138 of 141 (98%) Atlantic bottlenose dolphins (Tursiops truncatus), and 3 of 53 (6%) walruses (Odobenus rosmarus). For N. caninum, sera were diluted 1:40, 1:80, 1:160, and 1:320 and examined with the Neospora agglutination test (NAT) using mouse-derived tachyzoites. NAT antibodies were found in 3 of 53 (6%) walruses, 28 of 145 (19%) sea otters, 11 of 311 (3.5%) harbor seals, 1 of 27 (3.7%) sea lions, 4 of 32 (12.5%) ringed seals, 1 of 8 (12.5%) bearded seals, and 43 of 47 (91%) bottlenose dolphins. To our knowledge, this is the first report of N. caninum antibodies in any marine mammal, and the first report of T. gondii antibodies in walruses and in ringed, bearded, spotted, and ribbon seals. Current information on T. gondii-like and Sarcocystis-like infections in marine mammals is reviewed. New cases of clinical S. canis and T. gondii infections are also reported in sea lions, and T. gondii infection in an Antillean manatee (Trichechus manatus manatus).

Book review: Serendipity: An ecologist’s quest to understand nature

USGS Publications Warehouse

Ball, E. E.; Adams, D. M.; Dupuie, J. N.; Jones, M. M.; McGovern, P. G.; Ruden, R. M.; Schmidt, S.R.; Vaziri, G. J.; Eeling, J. S.; Kirk, B. D.; McCombs, A. L.; Rabinowitz, A. B.; Thompson, K. M.; Hudson, Z. J.; Klaver, Robert W.

2017-01-01

A common thought among graduate students is: “how do established scientists get where they are today?” In Serendipity: An Ecologist’s Quest to Understand Nature, James Estes offers a personal reflection on research experiences spanning his 50-year career, beginning as a Ph.D. student in 1970 and concluding with recognition as a member of the National Academy of Sciences in 2014. Estes chronologically outlines the foundational trophic cascade ecology research that he and colleagues conducted in the Aleutian Islands, examining key relationships among kelp forests, sea otters, sea urchins, and killer whales through anecdotal stories of achievement and challenge. Estes’ 3 main goals in writing this book are to: (1) recount what he had learned from 50 years of research;...

Phylogeography of the smooth-coated otter (Lutrogale perspicillata): distinct evolutionary lineages and hybridization with the Asian small-clawed otter (Aonyx cinereus)

PubMed Central

Moretti, Beatrice; Al-Sheikhly, Omar F.; Guerrini, Monica; Theng, Meryl; Gupta, Brij K.; Haba, Mukhtar K.; Khan, Waseem A.; Khan, Aleem A.; Barbanera, Filippo

2017-01-01

We investigated the phylogeography of the smooth-coated otter (Lutrogale perspicillata) to determine its spatial genetic structure for aiding an adaptive conservation management of the species. Fifty-eight modern and 11 archival (dated 1882–1970) otters sampled from Iraq to Malaysian Borneo were genotyped (mtDNA Cytochrome-b, 10 microsatellite DNA loci). Moreover, 16 Aonyx cinereus (Asian small-clawed otter) and seven Lutra lutra (Eurasian otter) were sequenced to increase information available for phylogenetic reconstructions. As reported in previous studies, we found that L. perspicillata, A. cinereus and A. capensis (African clawless otter) grouped in a clade sister to the genus Lutra, with L. perspicillata and A. cinereus being reciprocally monophyletic. Within L. perspicillata, we uncovered three Evolutionarily Significant Units and proved that L. p. maxwelli is not only endemic to Iraq but also the most recent subspecies. We suggest a revision of the distribution range limits of easternmost L. perspicillata subspecies. We show that smooth-coated otters in Singapore are L. perspicillata x A. cinereus hybrids with A. cinereus mtDNA, the first reported case of hybridization in the wild among otters. This result also provides evidence supporting the inclusion of L. perspicillata and A. cinereus in the genus Amblonyx, thus avoiding the paraphyly of the genus Aonyx. PMID:28128366

Diagnosis and seroprevalence of leptospirosis in California sea lions from coastal California.

PubMed

Colagross-Schouten, Angela M; Mazet, Jonna A K; Gulland, Frances M D; Miller, Melissa A; Hietala, Sharon

2002-01-01

The sensitivity and specificity of the microscopic agglutination test (MAT) as a method for detection of exposure to Leptospira spp. in California sea lions (Zalophus californianus) were determined. Sera came from individuals that demonstrated clinical signs of renal disease, had lesions suggestive of leptospirosis at necropsy, and had visible leptospires in silver stained kidney sections as positive controls. Sera from unexposed captive individuals were used as negative controls. The test was 100% sensitive at 1:3,200 for confirming renal infection and 100% specific at negative < 1:100 for detection of Leptospira interrogans scrovar pomona antibodies by MAT in California sea lions. Leptospira interrogans serovar pomona was used as a screening serovar because it has been isolated previously from the kidneys and placentas of California sea lions, and there appears to be cross-reactivity between serovar pomona and other serovars. Sera from 225 free-ranging California sea lions presented to one of three participating California (USA) coastal marine mammal rehabilitation centers in 1996 were then evaluated for antibodies to serovar pomona using the MAT. The overall seroprevalence was 38.2% (86/225), although the prevalence varied among locations from 100% (38/38) in animals at the Marine Mammal Care Center (Fort MacArthur, California, USA) to 0% (0/14) at SeaWorld California (San Diego, California). At The Marine Mammal Center (Sausalito, California) [prevalence 27.8% (48/173)], the majority of seropositive animals were subadults and adults, and males were 4.7 times more likely to be seropositive to serovar pomona than females. When combining results from all three centers, subadult and adult animals were more likely to be seropositive than pups and juvenile sea lions, and the highest proportion of seropositive animals presented during the autumn months. Serum elevations of blood urea nitrogen, creatinine, phosphorus, and/or calcium were associated with seropositivity to serovar pomona. We found no association between potassium or sodium levels and seropositivity.

Spectral Absorption of Solar Radiation by Aerosols during ACE-Asia

NASA Technical Reports Server (NTRS)

Bergstrom, R. W.; Pilewskie, P.; Pommier, J.; Rabbette, M.; Russell, P. B.; Schmid, B.; Redermann, J.; Higurashi, A.; Nakajima, T.; Quinn, P. K.

2004-01-01

As part of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia), the upward and downward spectral solar radiant fluxes were measured with the Spectral Solar Flux Radiometer (SSFR), and the aerosol optical depth was measured with the Ames Airborne Tracking Sunphotometer (AATS-14) aboard the Center for INterdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. IN this paper, we examine the data obtained for two cases: a moderately thick aerosol layer, 12 April, and a relatively thin aerosol case, 16 April 2001. ON both days, the Twin Otter flew vertical profiles in the Korean Strait southeast of Gosan Island. For both days we determine the aerosol spectral absorption of the layer and estimate the spectral aerosol absorption optical depth and single-scattering albedo. The results for 12 April show that the single-scattering albedo increases with wavelength from 0.8 at 400 nm to 0.95 at 900 nm and remains essentially constant from 950 to 1700 nm. On 16 April the amount of aerosol absorption was very low; however, the aerosol single-scattering albedo appears to decrease slightly with wavelength in the visible region. We interpret these results in light of the two absorbing aerosol species observed during the ACE-asia study: mineral dust and black carbon. The results for 12 April are indicative of a mineral dust-black carbon mixture. The 16 April results are possibly caused by black carbon mixed with nonabsorbing pollution aerosols. For the 12 April case we attempt to estimate the relative contributions of the black carbon particles and the mineral dust particles. We compare our results with other estimates of the aerosol properties from a Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) satellite analysis and aerosol measurements made aboard the Twin Otter, aboard the National Oceanic and Atmospheric Administration Ronald H Brown ship, and at ground sites in Gosan and Japan. The results indicate a relatively complicated aerosol mixture of both industrial pollution (including black carbon) and mineral dust. This underscores the need for careful measurements and analysis to separate out the absorption effects of mineral dust and black carbon in the east Asia region.

Exxon Valdez Oil Spill Restoration Project final report: Monitoring for evaluation of recovery and restoration of injured nearshore resources

USGS Publications Warehouse

Ballachey, Brenda E.; Bodkin, James L.; Kloecker, Kimberly A.; Dean, Tom; Colettie, Heather A

2015-01-01

In 2012, we completed three consecutive years of full field sampling in WPWS for EVOS Restoration Project 10100750. Nearshore monitoring was conducted in collaboration with the NPS SWAN I&M program and, beginning in 2012, as part of the EVOSTC GWA program. Data collection was done in accordance with standard operating procedures set forth to monitor marine water chemistry and quality, marine intertidal invertebrates, kelps and seagrasses, marine birds, black oystercatchers, and sea otters. Summer sampling in 2012 represented the fourth year of sampling in WPWS (an initial year of sampling was done in WPWS in 2007; EVOS Restoration Project 070750). Based on our monitoring of nearshore species in WPWS, and comparisons of data from WPWS and other areas within the Gulf of Alaska, we have no evidence of continued injury to biological resources at the spatial scales we are monitoring. A key finding is that recovery of the sea otter population is no longer constrained by exposure to lingering oil; this is consistent with related EVOSTC studies on harlequin ducks (Restoration Project 12120114-Q). We anticipate continued annual nearshore monitoring in WPWS and at KATM and KEFJ under GWA, with data summaries and analyses including all three areas to provide a larger spatial and temporal context to the understanding of processes and patterns in nearshore ecosystems of the GOA which were impacted by the EVOS of 1989.

Explicit Not Implicit Preferences Predict Conservation Intentions for Endangered Species and Biomes.

PubMed

Echeverri, Alejandra; Callahan, Megan M; Chan, Kai M A; Satterfield, Terre; Zhao, Jiaying

2017-01-01

Conservation of biodiversity is determined in part by human preferences. Preferences relevant to conservation have been examined largely via explicit measures (e.g., a self-reported degree of liking), with implicit measures (e.g., preconscious, automatic evaluations) receiving relatively less attention. This is the case despite psychological evidence from other contexts that implicit preferences are more informative of behavior. Thus, the type of measure that predicts conservation intentions for biodiversity is unknown. We conducted three studies to examine conservation intentions in light of people's explicit and implicit preferences toward four endangered species (sea otter, American badger, caribou, yellow-breasted chat) and four biomes (forest, ocean, grassland, tundra). In Study 1 (n = 55), we found that people implicitly preferred caribou most, but explicitly preferred sea otter most, with a significant multiple regression where participants' explicit preferences dictated their stated intended donations for conservation of each species. In Study 2 (n = 57) we found that people implicitly and explicitly preferred forest and ocean over grassland and tundra. Explicit rather than implicit preferences predicted the intended donation for conservation of the ocean biome. Study 3 involved a broader online sample of participants (n = 463) and also found that explicit preferences dictated the intended donations for conservation of biomes and species. Our findings reveal discrepancies between implicit and explicit preferences toward species, but not toward biomes. Importantly, the results demonstrate that explicit rather than implicit preferences predict conservation intentions for biodiversity. The current findings have several implications for conservation and the communication of biodiversity initiatives.

Sarcocyst Development in Raccoons (Procyon lotor) Inoculated with Different Strains of Sarcocystis neurona Culture-Derived Merozoites.

PubMed

Dryburgh, E L; Marsh, A E; Dubey, J P; Howe, D K; Reed, S M; Bolten, K E; Pei, W; Saville, W J A

2015-08-01

Sarcocystis neurona is considered the major etiologic agent of equine protozoal myeloencephalitis (EPM), a neurological disease in horses. Raccoon ( Procyon lotor ) is considered the most important intermediate host in the life cycle of S. neurona in the United States; S. neurona sarcocysts do mature in raccoon muscles, and raccoons also develop clinical signs simulating EPM. The focus of this study was to determine if sarcocysts would develop in raccoons experimentally inoculated with different host-derived strains of in vitro-cultivated S. neurona merozoites. Four raccoons were inoculated with strains derived from a raccoon, a sea otter, a cat, and a horse. Raccoon tissues were fed to laboratory-raised opossums ( Didelphis virginiana ), the definitive host of S. neurona . Intestinal scraping revealed sporocysts in opossums who received muscle tissue from raccoons inoculated with the raccoon-derived or the sea otter-derived isolates. These results demonstrate that sarcocysts can mature in raccoons inoculated with in vitro-derived S. neurona merozoites. In contrast, the horse and cat-derived isolates did not produce microscopically or biologically detected sarcocysts. Immunoblot analysis revealed both antigenic and antibody differences when testing the inoculated raccoons. Immunohistochemical staining indicated differences in staining between the merozoite and sarcocyst stages. The successful infections achieved in this study indicates that the life cycle can be manipulated in the laboratory without affecting subsequent stage development, thereby allowing further purification of strains and artificial maintenance of the life cycle.

50 CFR 23.69 - How can I trade internationally in fur skins and fur skin products of bobcat, river otter, Canada...

Code of Federal Regulations, 2010 CFR

2010-10-01

... skins and fur skin products of bobcat, river otter, Canada lynx, gray wolf, and brown bear? 23.69... skins and fur skin products of bobcat, river otter, Canada lynx, gray wolf, and brown bear? (a) U.S. and...), river otter (Lontra canadensis), and Canada lynx (Lynx canadensis), and the Alaskan populations of gray...

50 CFR 23.69 - How can I trade internationally in fur skins and fur skin products of bobcat, river otter, Canada...

Code of Federal Regulations, 2011 CFR

2011-10-01

... skins and fur skin products of bobcat, river otter, Canada lynx, gray wolf, and brown bear? 23.69... skins and fur skin products of bobcat, river otter, Canada lynx, gray wolf, and brown bear? (a) U.S. and...), river otter (Lontra canadensis), and Canada lynx (Lynx canadensis), and the Alaskan populations of gray...

50 CFR 23.69 - How can I trade internationally in fur skins and fur skin products of bobcat, river otter, Canada...

Code of Federal Regulations, 2013 CFR

2013-10-01

... skins and fur skin products of bobcat, river otter, Canada lynx, gray wolf, and brown bear? 23.69... skins and fur skin products of bobcat, river otter, Canada lynx, gray wolf, and brown bear? (a) U.S. and...), river otter (Lontra canadensis), and Canada lynx (Lynx canadensis), and the Alaskan populations of gray...

Effects of potential surface coal mining on dissolved solids in Otter Creek and in the Otter Creek alluvial aquifer, southeastern Montana

USGS Publications Warehouse

Cannon, M.R.

1985-01-01

Otter Creek drains an area of 709 square miles in the coal-rich Powder River structural basin of southeastern Montana. The Knobloch coal beds in the Tongue River Member of the Paleocene Fort Union Formation is a shallow aquifer and a target for future surface mining in the downstream part of the Otter Creek basin. A mass-balance model was used to estimate the effects of potential mining on the dissolved solids concentration in Otter Creek and in the alluvial aquifer in the Otter Creek valley. With extensive mining of the Knobloch coal beds, the annual load of dissolved solids to Otter Creek at Ashland at median streamflow could increase by 2,873 tons, or a 32-percent increase compared to the annual pre-mining load. Increased monthly loads of Otter Creek, at the median streamflow, could range from 15 percent in February to 208 percent in August. The post-mining dissolved solids load to the subirrigated part of the alluvial valley could increase by 71 percent. The median dissolved solids concentration in the subirrigated part of the valley could be 4,430 milligrams per liter, compared to the pre-mining median concentration of 2,590 milligrams per liter. Post-mining loads from the potentially mined landscape were calculated using saturated-paste-extract data from 506 overburdened samples collected from 26 wells and test holes. Post-mining loads to the Otter Creek valley likely would continue at increased rates for hundreds of years after mining. If the actual area of Knobloch coal disturbed by mining were less than that used in the model, post-mining loads to the Otter Creek valley would be proportionally smaller. (USGS)

Intestinal helminths of river otters (Lutra canadensis) from the Pacific Northwest

USGS Publications Warehouse

Hoberg, Eric P.; Henny, Charles J.; Hedstrom, O.R.; Grove, Robert A.

1997-01-01

The intestinal helminth fauna of river otters, Lutra canadensis, from the Pacific Northwest was characterized by low species richness and intensity of infection. River otters from the lower Columbia River (n = 23) were infected with 9 species of helminths (83% prevalence); those from a relatively undisturbed reference area near the headwaters of the Trask and Wilson rivers on the Oregon coast (n = 6) were infected by 5 species of helminths (100% prevalence). Single species of Eucestoda (Schistocephalus solidus), Digenea (Euparyphium inerme), Acanthocephala (Corynosoma strumosum), and 8 species of Nematoda (Strongyloides lutrae; larvae of Eustrongylides sp., Anisakis sp., and Contracaecum sp.; 3 of Cystidicolidae, and Hedruris sp.) were collected. Most species are typical of piscine definitive hosts and were present as incidental parasites of river otters. Notably, specimens of Euparyphium inerme are reported for the first time in river otters from North America; occurrence of other helminths constitutes new host or geographic records for parasites in river otters in Oregon and Washington. Parasites with marine life cycles were acquired by river otters in freshwater habitats at a great distance from the ocean. The helminth fauna of river otters in the Pacific Northwest was influenced primarily by ecological factors and was indicative of eclectic food habits and the relatively extensive home ranges occupied by these mustelids.

Current distribution of North American river otters in central and eastern Oklahoma, with seven new county records

USGS Publications Warehouse

Barrett, Dominic A.; Leslie, David M.

2010-01-01

In 1984 and 1985, the Oklahoma Department of Wildlife Conservation reintroduced North American river otters (Lontra canadensis) from coastal Louisiana into eastern Oklahoma. Those reintroductions and immigration from Arkansas and possibly northeastern Texas allowed river otters to become reestablished in eastern Oklahoma. Our goals were to determine the contemporary distribution of river otters in central and eastern Oklahoma with voucher specimens, sign surveys, and mail surveys and to compare proportion of positive detections among watersheds. We report new distributional records with voucher specimens from seven counties (Adair, Bryan, Coal, Johnston, McIntosh, Okfuskee, Tulsa) in Oklahoma. We also provide locality information for specimens collected from four counties (Haskell, McCurtain, Muskogee, Wagoner) where river otters were described in published literature but no voucher specimens existed. During winter and spring 2006 and 2007, we visited 340 bridge sites in 28 watersheds in eastern and central Oklahoma and identified river otter signs in 16 counties where river otters were not previously documented in published literature or by voucher specimens. Proportion of positive sites within each watershed ranged 0–100%. Mail surveys suggested that river otters occurred in eight additional counties where they were not previously documented by published literature, voucher specimens, or sign-survey efforts.

Effect of deflector curvature on hydrodynamic performances of a double-slotted cambered otter-board

NASA Astrophysics Data System (ADS)

WANG, Lei; Wang, Lu Min; Shi, Jian Gao; Yu, Wen Wen; Qi, Guang Rui; Zhang, Xun; Zhang, Rong Jun; Zhang, Tian Shu

2018-06-01

The effect of deflector curvature on hydrodynamic performances of a double-slotted cambered otter-board was investigated using engineering models in a wind tunnel. Four different curvature (0.06,0.09, 0.12 and 0.15) were evaluated at a wind speed of 28 m/s. Parameters measured included: drag coefficient Cx, lift coefficient Cy, pitch moment coefficient Cm, center of pressure coefficient Cp , over a range of angle of attack (0° to 70°). These coefficients were used in analyzing the differences in the performance among the four otter-board models. Results showed that the maximum lift coefficient Cy of the otter-board model with the curvature (0.06) of two deflectors was highest (2.020 at °=55°). The maximum Cy/Cx of the otter-board with the curvature (0.12) of two deflectors was highest (3.655 at °=22.5°). A comparative analysis of Cm and Cp showed that the stability of otter-board model with the curvature (0.12) of two deflectors is better in pitch, and the stability of otter-board model with the curvature (0.06) of two deflectors is better in roll. The findings of this study can offer useful reference data for the structural optimization of otter-boards for trawling.

Effect of panel shape on hydrodynamic performances of vertical v-shaped double- slotted cambered otter-board

NASA Astrophysics Data System (ADS)

Wang, Lei; Zhang, Xun; Wang, Lu Min; Huang, Hong Liang; Zhang, Yu; Liu, Yong Li; Feng, Wei Dong; Zhang, Rong Jun

2018-06-01

The effect of panel shape on hydrodynamic performances of a vertical v-shaped double-slotted cambered otter-board was investigated using engineering models in a wind tunnel. Three different shape panels (rhomboid, left trapezoid and isosceles trapezoid) were evaluated at a wind speed of 28 m/s. Parameters measured included: drag coefficient Cx, lift coefficient Cy, pitch moment coefficient Cm, center of pressure coefficient Cp , over a range of angle of attack (0° to 70°). These coefficients were used in analyzing the differences in the performance among the three otter-board models. Results showed that the maximum lift coefficient Cy of the otter-board model with the isosceles trapezoid shape panels was highest (2.103 at α=45°). The maximum Cy/Cx of the otter-board with the rhomboid shape panels was highest (3.976 at α=15°). A comparative analysis of Cm and Cp showed that the stability of otter-board model with the isosceles trapezoid shape panels is better in pitch, and the stability of otter-board model with the left trapezoid shape panels is better in roll. The findings of this study can offer useful reference data for the structural optimization of otter-boards for trawling.

The Fecal Viral Flora of California Sea Lions▿†

PubMed Central

Li, Linlin; Shan, Tongling; Wang, Chunlin; Côté, Colette; Kolman, John; Onions, David; Gulland, Frances M. D.; Delwart, Eric

2011-01-01

California sea lions are one of the major marine mammal species along the Pacific coast of North America. Sea lions are susceptible to a wide variety of viruses, some of which can be transmitted to or from terrestrial mammals. Using an unbiased viral metagenomic approach, we surveyed the fecal virome in California sea lions of different ages and health statuses. Averages of 1.6 and 2.5 distinct mammalian viral species were shed by pups and juvenile sea lions, respectively. Previously undescribed mammalian viruses from four RNA virus families (Astroviridae, Picornaviridae, Caliciviridae, and Reoviridae) and one DNA virus family (Parvoviridae) were characterized. The first complete or partial genomes of sapeloviruses, sapoviruses, noroviruses, and bocavirus in marine mammals are reported. Astroviruses and bocaviruses showed the highest prevalence and abundance in California sea lion feces. The diversity of bacteriophages was higher in unweaned sea lion pups than in juveniles and animals in rehabilitation, where the phage community consisted largely of phages related to the family Microviridae. This study increases our understanding of the viral diversity in marine mammals, highlights the high rate of enteric viral infections in these highly social carnivores, and may be used as a baseline viral survey for comparison with samples from California sea lions during unexplained disease outbreaks. PMID:21795334

Butyltin compounds in River Otters (Lutra canadensis) from the Northwestern United States

USGS Publications Warehouse

Kannan, K.; Grove, Robert A.; Senthilkumar, K.; Henny, Charles J.; Geisy, J.P.

1999-01-01

Butyltin compounds, including mono-, di-, and tributyltin (MBT, DBT, and TBT) were measured in livers of 40 adult river otters (Lutra canadensis) collected from rivers and coastal bays in Washington and Oregon, USA. Butyltins were found in all the river otters, at a concentration range of 8.5a??2,610 ng/g, WW. The greatest concentration of total butyltins of 2,610 ng/g, WW, was found in a river otter collected in Puget Sound from Fort Ward, Washington. River otters collected near areas with major shipping activities, such as the Puget Sound, contained significantly greater concentrations (geometric mean: 367 ng/g, WW) of butyltins than those from rivers. Among butyltin compounds, MBT and DBT predominated in livers. The concentrations of butyltins in river otters ranged from comparable (Puget Sound) to less (rivers) than what was found in coastal cetaceans.

Uranium-Series Ages of Marine Terrace Corals from the Pacific Coast of North America and Implications for Last-Interglacial Sea Level History

USGS Publications Warehouse

Muhs, D.R.; Kennedy, G.L.; Rockwell, T.K.

1994-01-01

Few of the marine terraces along the Pacific coast of North America have been dated using uranium-series techniques. Ten terrace sequences from southern Oregon to southern Baja California Sur have yielded fossil corals in quantities suitable for U-series dating by alpha spectrometry. U-series-dated terraces representing the ???80,000 yr sea-level high stand are identified in five areas (Bandon, Oregon; Point Arena, San Nicolas Island, and Point Loma, California; and Punta Banda, Baja California); terraces representing the ???125,000 yr sea-level high stand are identified in eight areas (Cayucos, San Luis Obispo Bay, San Nicolas Island, San Clemente Island, and Point Loma, California; Punta Bands and Isla Guadalupe, Baja California; and Cabo Pulmo, Baja California Sur). On San Nicolas Island, Point Loma, and Punta Bands, both the ???80,000 and the ???125,000 yr terraces are dated. Terraces that may represent the ???105,000 sea-level high stand are rarely preserved and none has yielded corals for U-series dating. Similarity of coral ages from midlatitude, erosional marine terraces with coral ages from emergent, constructional reefs on tropical coastlines suggests a common forcing mechanism, namely glacioeustatically controlled fluctuations in sea level superimposed on steady tectonic uplift. The low marine terrace dated at ???125,000 yr on Isla Guadalupe, Baja California, presumed to be tectonically stable, supports evidence from other localities for a +6-m sea level at that time. Data from the Pacific Coast and a compilation of data from other coasts indicate that sea levels at ???80,000 and ???105,000 yr may have been closer to present sea level (within a few meters) than previous studies have suggested.

Assessing Withering Syndrome Resistance in California Black Abalone: Implications for Conservation and Restoration

DTIC Science & Technology

2009-01-29

worldwide. California Sea Grant College Program UC San Diego Title: Assessing withering syndrome resistance in California black abalone : Implications...Hunter S.(2009). Assessing withering syndrome resistance in California black abalone : Implications for conservation and restoration. UC San Diego...California Sea Grant College Program. Retrieved from: http://escholarship.org/uc/item/7c39q78n Keywords: black abalone , Haliotis cracherodii, captive breeding

The Vocal Repertoire of Adult and Neonate Giant Otters (Pteronura brasiliensis)

PubMed Central

Mumm, Christina A. S.; Knörnschild, Mirjam

2014-01-01

Animals use vocalizations to exchange information about external events, their own physical or motivational state, or about individuality and social affiliation. Infant babbling can enhance the development of the full adult vocal repertoire by providing ample opportunity for practice. Giant otters are very social and frequently vocalizing animals. They live in highly cohesive groups, generally including a reproductive pair and their offspring born in different years. This basic social structure may vary in the degree of relatedness of the group members. Individuals engage in shared group activities and different social roles and thus, the social organization of giant otters provides a basis for complex and long-term individual relationships. We recorded and analysed the vocalizations of adult and neonate giant otters from wild and captive groups. We classified the adult vocalizations according to their acoustic structure, and described their main behavioural context. Additionally, we present the first description of vocalizations uttered in babbling bouts of new born giant otters. We expected to find 1) a sophisticated vocal repertoire that would reflect the species’ complex social organisation, 2) that giant otter vocalizations have a clear relationship between signal structure and function, and 3) that the vocal repertoire of new born giant otters would comprise age-specific vocalizations as well as precursors of the adult repertoire. We found a vocal repertoire with 22 distinct vocalization types produced by adults and 11 vocalization types within the babbling bouts of the neonates. A comparison within the otter subfamily suggests a relation between vocal and social complexity, with the giant otters being the socially and vocally most complex species. PMID:25391142

Lower Clearwater Aquatic Mammal Survey. Final Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mack, Curt; Kronemann, Loren A.; Eneas, Cheryl

BPA provided funding to collect baseline data on river otters to assist in developing mitigation implementation plans for river otters percent to the Northwest Power Planning Council's Columbia River Basin Fish and Wildlife Program, sections 1003 (b)(2) and (3). Distribution, movements, habitat use, and diets of river otters were investigated in the Clearwater River within the Nez Perce Indian Reservation from 1991-1992. The study outlined recommendations to guide development of mitigation implementation plans for riparian habitats. Sections of the Clearwater River were identified that if protected or enhanced would provide optimal benefit to otters. Habitat improvement alternatives were also outlinedmore » which could be used to enhance otter habitats.« less

Territoriality of Giant Otter Groups in an Area with Seasonal Flooding

PubMed Central

Leuchtenberger, Caroline; Magnusson, William E.; Mourão, Guilherme

2015-01-01

Territoriality carries costs and benefits, which are commonly affected by the spatial and temporal abundance and predictability of food, and by intruder pressure. Giant otters (Pteronura brasiliensis) live in groups that defend territories along river channels during the dry season using chemical signals, loud vocalizations and agonistic encounters. However, little is known about the territoriality of giant otters during the rainy season, when groups leave their dry season territories and follow fish dispersing into flooded areas. The objective of this study was to analyze long-term territoriality of giant otter groups in a seasonal environment. The linear extensions of the territories of 10 giant otter groups were determined based on locations of active dens, latrines and scent marks in each season. Some groups overlapped the limits of neighboring territories. The total territory extent of giant otters was correlated with group size in both seasons. The extent of exclusive territories of giant otter groups was negatively related to the number of adults present in adjacent groups. Territory fidelity ranged from 0 to 100% between seasons. Some groups maintained their territory for long periods, which demanded constant effort in marking and re-establishing their territories during the wet season. These results indicate that the defense capacity of groups had an important role in the maintenance of giant otter territories across seasons, which may also affect the reproductive success of alpha pairs. PMID:25955248

Contaminants still high in top-level carnivores in the Southern California Bight: levels of DDT and PCBs in resident and transient pinnipeds.

PubMed

Blasius, Mary Ellen; Goodmanlowe, Gwen D

2008-12-01

Highly industrialized areas, such as the Southern California Bight, often have high levels of contaminants in marine sediments, which can cause chronic exposure to organisms long after their use has ceased. tDDT and tPCB were analyzed in the blubber of 145 stranded pinnipeds that died at local marine mammal centers between 1994 and 2006. Resident species (California sea lion and Pacific harbor seal) had significantly higher concentrations of tDDT and tPCB than the transient species (northern elephant seal). Adult female California sea lions had significantly lower concentrations of tDDT and tPCB than pups, yearlings, and adult males. Concentrations of both tDDT and tPCB in California sea lions significantly declined over time, but did not change in northern elephant seals. Current concentrations of tDDT and tPCB in California sea lions and harbor seals are among the highest values reported worldwide for marine mammals and exceed those reported to cause adverse health effects.

Comparative macroanatomical study of the neurocranium in some carnivora.

PubMed

Karan, M; Timurkaan, S; Ozdemir, D; Unsaldi, E

2006-02-01

This study was carried out to investigate the specific anatomical features of the neurocranium of the skull of the dog, cat, badger, marten and otter. Twenty-five animals (five from each species) were used without sexual distinction. The neurocranium consists of os occipitale, os sphenoidale, os pterygoideum, os ethmoidale, vomer, os temporale, os parietale and os frontale. The processus paracondylaris is projected ventrally in the cat, dog, marten and badger, and caudally in the otter. Two foramina were found laterally on each side of the protuberantia occipitalis externa in the otter, and one foramen was found near the protuberantia occipitalis externa in the badger. Foramen was not seen in other species. Paired ossa parietalia joined each other at the midline, forming the sutura sagittalis in the badger, dog, otter and cat while it was separated by the linea temporalis in the marten. The os frontale was small in otters, narrow and long in martens, and quite wide in cats and dogs. The bulla tympanica was rounded in the marten, dog, cat and badger, dorsoventral compressed in otter, and it was very large in all species examined. These observations represented interspecies differences in the neurocranium of marten, otter, badger, cat and dog.

A Systematic Review of Changes in Marine Mammal Health in North America, 1972-2012: The Need for a Novel Integrated Approach

PubMed Central

Simeone, Claire A.

2015-01-01

Marine mammals are often cited as “sentinels of ocean health” yet accessible, synthesized data on their health changes that could effectively warn of ocean health changes are rare. The objectives of this study were to 1) perform a systematic review of published cases of marine mammal disease to determine spatial and temporal trends in disease from 1972–2012, including changes in regions and taxa affected and specific causes; and 2) compare numbers of published cases of neoplasia with known, hospital-based neoplasia records to explore the causes of discrepancy between numbers of published cases and true disease trends. Peer-reviewed literature was compiled, and data were collected from The Marine Mammal Center database in Sausalito, California for comparison of numbers of neoplasia cases. Toxicoses from harmful algal blooms appear to be increasing. Viral epidemics are most common along the Atlantic U.S. coastline, while bacterial epidemics, especially leptospirosis, are most common along the Pacific coast. Certain protozoal and fungal zoonoses appear to be emerging, such as Toxoplasma gondii in southern sea otters in California, and Cryptococcus gattii in cetaceans in the Pacific Northwest. Disease reports were most common from California where pinniped populations are large, but increased effort also occurs. Anthropogenic trauma remains a large threat to marine mammal health, through direct mortality and indirect chronic disease. Neoplasia cases were under-reported from 2003–2012 when compared to true number of cases, and over-reported in several years due to case duplication. Peer-reviewed literature greatly underestimates the true magnitude of disease in marine mammals as it focuses on novel findings, fails to reflect etiology of multifactorial diseases, rarely reports prevalence rather than simple numbers of cases, and is typically presented years after a disease first occurs. Thus literature cannot guide management actions adequately, nor inform indices of ocean health. A real-time, nationally centralized system for reporting marine mammal disease data is needed to be able to understand how marine mammal diseases are changing with ecosystem changes, and before these animals can truly be considered ‘sentinels of ocean health’. PMID:26579715

PATHOGENIC LEPTOSPIRA SEROVARS IN FREE-LIVING SEA LIONS IN THE GULF OF CALIFORNIA AND ALONG THE BAJA CALIFORNIA COAST OF MEXICO.

PubMed

Avalos-Téllez, Rosalía; Carrillo-Casas, Erika M; Atilano-López, Daniel; Godínez-Reyes, Carlos R; Díaz-Aparicio, Efrén; Ramírez-Delgado, David; Ramírez-Echenique, María F; Leyva-Leyva, Margarita; Suzán, Gerardo; Suárez-Güemes, Francisco

2016-04-28

The California sea lion ( Zalophus californianus ), a permanent inhabitant of the Gulf of California in Mexico, is susceptible to pathogenic Leptospira spp. infection, which can result in hepatic and renal damage and may lead to renal failure and death. During summer 2013, we used the microscopic agglutination test (MAT) to investigate the prevalence of anti-Leptospira antibodies in blood of clinically healthy sea lion pups from seven rookery islands on the Pacific Coast of Baja California (Pacific Ocean) and in the Gulf of California. We also used PCR to examine blood for Leptospira DNA. Isolation of Leptospira in liquid media was unsuccessful. We found higher antibody prevalence in sea lions from the rookery islands in the gulf than in those from the Pacific Coast. Antibodies against 11 serovars were identified in the Gulf of California population; the most frequent reactions were against serovars Bataviae (90%), Pyrogenes (86%), Wolffi (86%), Celledoni (71%), and Pomona (65%). In the Pacific Ocean population, MAT was positive against eight serovars, where Wolffi (88%), Pomona (75%), and Bataviae (70%) were the most frequent. Serum samples agglutinated with more than one Leptospira serovar. The maximum titer was 3,200. Each island had a different serology profile, and islands combined showed a distinct profile for each region. We detected pathogenic Leptospira DNA in 63% of blood samples, but we found no saprophytic Leptospira. Positive PCR results were obtained in blood samples with high and low MAT titers. Together, these two methods enhance the diagnosis and interpretation of sea lion leptospirosis. Our results may be related to human activities or the presence of other reservoirs with which sea lions interact, and they may also be related to sea lion stranding.

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest) California Sea Mussel and Bay Mussel

DTIC Science & Technology

1988-09-01

FishesS and Invertebrates (Pacific Southwest) CALIFORNIA SEA MUSSEL AND BAY MUSSEL Cn Coastal Ecology Group *Fish and Wildlife Service Waterways...September 1988 Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest) CALIFORNIA SEA MUSSEL...AND BAY MUSSEL by William N. Shaw Fred Telonicher Marine Laboratory Humboldt State University Trinidad, CA 95570 Thomas J. Hassler U.S. Fish anu

Distribution and density of marine birds and mammals along the Kenai Fjords National Park coastline - March 2010

USGS Publications Warehouse

Coletti, Heather A.; Bodkin, James L.; Esslinger, George G.

2011-01-01

From March 21, 2010 to March 24, 2010, a winter marine bird and mammal skiff-based survey along the coast of Kenai Fjords National Park (KEFJ) was completed. This was the second winter survey completed for KEFJ since 2008. The primary objectives of the SWAN winter surveys are to characterize the species composition, density and distribution of the overwintering marine ducks prior to their migration to breeding grounds. Seasonal differences in species composition, distribution and density of other marine birds and mammals are also documented. The overall design calls for the sampling of the same transects during both the winter and summer surveys if safe and appropriate conditions allow. The 2010 survey took approximately four days to complete with a crew of six. The most common birds observed on the nearshore transects were the Barrow’s goldeneye (29.35/km2 , SE=9.24) and harlequin duck (29.30/km2 , SE=4.72). Harlequin ducks tended to be more evenly distributed along the coastline while Barrow’s goldeneye tended to be observed in less exposed areas along the coast and in larger groups. In contrast, the most abundant marine bird in KEFJ summer surveys is the Glaucous-winged gull, while Barrow’s goldeneye are nearly absent along the KEFJ coast. The most common marine mammal was the harbor seal (6.75/km2 , se=2.93) followed by the sea otter (3.59/km2 , se=0.90, adults and pups). Densities of harbor seals and sea otters in the summer were similar to the winter estimates.

Sea otters, social justice, and ecosystem-service perceptions in Clayoquot Sound, Canada.

PubMed

Levine, Jordan; Muthukrishna, Michael; Chan, Kai M A; Satterfield, Terre

2017-04-01

We sought to take a first step toward better integration of social concerns into empirical ecosystem service (ES) work. We did this by adapting cognitive anthropological techniques to study the Clayoquot Sound social-ecological system on the Pacific coast of Canada's Vancouver Island. We used freelisting and ranking exercises to elicit how locals perceive ESs and to determine locals' preferred food species. We analyzed these data with the freelist-analysis software package ANTHROPAC. We considered the results in light of an ongoing trophic cascade caused by the government reintroduction of sea otters (Enhydra lutris) and their spread along the island's Pacific coast. We interviewed 67 local residents (n = 29 females, n = 38 males; n = 26 self-identified First Nation individuals, and n = 41 non-First Nation individuals) and 4 government managers responsible for conservation policy in the region. We found that the mental categories participants-including trained ecologists-used to think about ESs, did not match the standard academic ES typology. With reference to the latest ecological model projections for the region, we found that First Nations individuals and women were most likely to perceive the most immediate ES losses from the trophic cascade, with the most certainty. The inverse was found for men and non-First Nations individuals, generally. This suggests that 2 historically disadvantaged groups (i.e., First Nations and women) are poised to experience the immediate impacts of the government-initiated trophic cascade as yet another social injustice in a long line of perceived inequities. Left unaddressed, this could complicate efforts at multistakeholder ecosystem management in the region. © 2016 Society for Conservation Biology.

Stability and change in kelp forest habitats at San Nicolas Island

USGS Publications Warehouse

Kenner, Michael C.; Tinker, M. Tim

2018-01-01

Kelp forest communities are highly variable over space and time. Despite this complexity it has been suggested that kelp forest communities can be classified into one of 2 states: kelp dominated or sea urchin dominated. It has been further hypothesized that these represent “alternate stable states” because a site can remain in either of these states for decades before some perturbation causes a rapid shift to the other state. Our research group has maintained a subtidal community monitoring program for 38 years at San Nicolas Island consisting of twice-annual scuba-based surveys at 6 sites distributed within 4 regions around the island. Three types of perturbations are thought to be relevant to subtidal community dynamics at San Nicolas: (1) physical disturbances in the form of major storm and El Niño/Southern Oscillation (ENSO) events; (2) invertebrate diseases, which periodically decimate urchin populations; and (3) the reintroduction and subsequent increase of sea otters (Enhydra lutris nereis). These 3 perturbations differ in spatial and temporal specificity; physical disturbances and disease outbreaks occur periodically and could affect all 4 regions, while sea otter predation has been concentrated primarily at the West End sites over the last 15 years. The different types of perturbations and the duration of the time series at the kelp forests at San Nicolas make the data set ideal for testing the “alternate stable state” hypothesis. We use nonmetric multidimensional scaling (NMDS) to examine spatial and temporal patterns of community similarity at the 4 regions. In particular, we evaluate support for the existence of stable states, which are represented on NMDS plots as distinct spatial clusters. Community dynamics at each site approximated a biased random walk in NMDS space, with one or more basins of attraction and occasional jumps between basins. We found evidence for alternative stable states at some sites, and we show that transitions from one stable state to another may be influenced by interactions between multiple perturbations.

Assessing Temperature Risk to Crab in the Northeast Pacific (Southern California to the Beaufort Sea)

EPA Science Inventory

To evaluate the vulnerability of the Brachyura crabs (<200 m) to projected increases in sea surface temperature (SST), we developed an approach that evaluates risk within each of the ten Marine Ecoregions of the World (MEOW) ranging from Southern California to the Beaufort Sea...

PCBs, organochlorine pesticides, and reproduction in river otters from Louisiana

USGS Publications Warehouse

Fleming, W.J.; Bunck, C.M.; Linscombe, G.; Kinler, N.; Stafford, C.J.

1985-01-01

Reproductive tracts from 89 3-year-old female river otters (Lutra canadensis), from Louisiana were examined. Eighteen of these were in a reproductive phase out of synchrony with the expected population norms. Eight of 32 otters had fewer embryos than corpora lutea, indicating intrauterine mortality in 25% of the sample. Chemical analyses of liver tissue from 57 otters revealed a low prevalence of polychlorinated biphenyls (PCB) and organochlorine pesticide contamination. These low Ievels of organochlorine compounds were not associated with atypical reproductive synchrony or intrauterine mortality.

Bioenergetics assessment of fish and crayfish consumption by river otter (Lontra canadensis): integrating prey availability, diet, and field metabolic rate

USGS Publications Warehouse

Dekar, Matthew P.; Magoulick, Daniel D.; Beringer, J.

2010-01-01

River otters (Lontra canadensis) are important predators in aquatic ecosystems, but few studies quantify their prey consumption. We trapped crayfish monthly as an index of availability and collected otter scat for diet analysis in the Ozark Mountains of northwestern Arkansas, USA. We measured otter daily energy expenditure (DEE) with the doubly labeled water method to develop a bioenergetics model for estimating monthly prey consumption. Meek's crayfish (Orconectes meeki) catch-per-unit-effort was positively related to stream temperature, indicating that crayfish were more available during warmer months. The percentage frequency of occurrence for crayfish in scat samples peaked at 85.0% in summer and was lowest (42.3%) in winter. In contrast, the percentage occurrence of fish was 13.3% in summer and 57.7% in winter. Estimates of DEE averaged 4738 kJ·day-1 for an otter with a body mass of 7842 g. Total biomass consumption ranged from 35 079 to 52 653 g·month-1 (wet mass), corresponding to a high proportion of fish and crayfish in the diet, respectively. Otter consumption represents a large fraction of prey production, indicating potentially strong effects of otters on trophic dynamics in stream ecosystems.

Helicobacter spp. from captive bottlenose dolphins (Tursiops spp.) and polar bears (Ursus maritimus).

PubMed

Oxley, Andrew P A; Argo, Jeffrey A; McKay, David B

2005-11-01

The gastric fluid of six bottlenose dolphins and the faeces of four polar bears from the same oceanarium were examined for the presence of Helicobacter. As detected by PCR, all dolphins and 8/12 samples collected from polar bears were positive for Helicobacter. Novel sequence types were identified in samples collected from these animals of which several were unique to either the dolphins or the polar bears. At least one sequence type was, however, detected in both animal taxa. In addition, a sequence type from a dolphin shared a 98.2-100% identity to sequences from other Helicobacter species from harp seals, sea otters and sea lions. This study reports on the occurrence of novel Helicobacter sequence types in polar bears and dolphins and demonstrates the broad-host range of some species within these animals.

Evaluating the status of individuals and populations: Advantages of multiple approaches and time scales: Chapter 6

USGS Publications Warehouse

Monson, Daniel H.; Bowen, Lizabeth

2015-01-01

Overall, a variety of indices used to measure population status throughout the sea otter’s range have provided insights for understanding the mechanisms driving the trajectory of various sea otter populations, which a single index could not, and we suggest using multiple methods to measure a population’s status at multiple spatial and temporal scales. The work described here also illustrates the usefulness of long-term data sets and/or approaches that can be used to assess population status retrospectively, providing information otherwise not available. While not all systems will be as amenable to using all the approaches presented here, we expect innovative researchers could adapt analogous multi-scale methods to a broad range of habitats and species including apex predators occupying the top trophic levels, which are often of conservation concern.

Differential resilience of Amazonian otters along the Rio Negro in the aftermath of the 20th century international fur trade.

PubMed

Pimenta, Natalia C; Antunes, André P; Barnett, Adrian A; Macedo, Valêncio W; Shepard, Glenn H

2018-01-01

Commercial hunting for the international trade in animal hides in the 20th century decimated many populations of aquatic wildlife in Amazonia. However, impacts varied significantly between different species and regions, depending upon hunting intensity, accessibility of habitat, and the inherent resilience of various species and their habitats. We investigated the differential responses of two Amazonian Mustelid species, the neotropical otter and giant otter, to commercial hunting pressure along the upper Rio Negro in Brazil, and examined historical factors that influenced spatial and temporal variation in commercial exploitation. We analyzed previously unanalyzed data from historical records of hide shipments to track changes in hide sales and prices for the two species in the late 20th century. We also gathered oral histories from older Baniwa people who had witnessed or participated in commercial otter hunting. These complimentary data sources reveal how intrinsic biological and social characteristics of the two otter species interacted with market forces and regional history. Whereas giant otter populations were driven to local or regional extinction during the late 20th century by commercial hunting, neotropical otters persisted. In recent decades, giant otter populations have returned to some parts of the upper Rio Negro, a development which local people welcome as part of a generalized recovery of the ecosystems in their territory as a result of the banning of animal pelt exports and indigenous land demarcation. This paper expands the scope of the field historical ecology and reflects on the role of local knowledge in biodiversity conservation.

Differential resilience of Amazonian otters along the Rio Negro in the aftermath of the 20th century international fur trade

PubMed Central

Antunes, André P.; Barnett, Adrian A.; Macedo, Valêncio W.; Shepard, Glenn H.

2018-01-01

Commercial hunting for the international trade in animal hides in the 20th century decimated many populations of aquatic wildlife in Amazonia. However, impacts varied significantly between different species and regions, depending upon hunting intensity, accessibility of habitat, and the inherent resilience of various species and their habitats. We investigated the differential responses of two Amazonian Mustelid species, the neotropical otter and giant otter, to commercial hunting pressure along the upper Rio Negro in Brazil, and examined historical factors that influenced spatial and temporal variation in commercial exploitation. We analyzed previously unanalyzed data from historical records of hide shipments to track changes in hide sales and prices for the two species in the late 20th century. We also gathered oral histories from older Baniwa people who had witnessed or participated in commercial otter hunting. These complimentary data sources reveal how intrinsic biological and social characteristics of the two otter species interacted with market forces and regional history. Whereas giant otter populations were driven to local or regional extinction during the late 20th century by commercial hunting, neotropical otters persisted. In recent decades, giant otter populations have returned to some parts of the upper Rio Negro, a development which local people welcome as part of a generalized recovery of the ecosystems in their territory as a result of the banning of animal pelt exports and indigenous land demarcation. This paper expands the scope of the field historical ecology and reflects on the role of local knowledge in biodiversity conservation. PMID:29601590

Trophic interactions of the endangered Southern river otter ( Lontra provocax) in a Chilean Ramsar wetland inferred from prey sampling, fecal analysis, and stable isotopes

NASA Astrophysics Data System (ADS)

Franco, Marcela; Guevara, Giovany; Correa, Loreto; Soto-Gamboa, Mauricio

2013-04-01

Non-invasive methodological approaches are highly recommended and commonly used to study the feeding ecology of elusive and threatened mammals. In this study, we use multiple lines of evidence to assess the feeding strategies of the endangered Southern river otter, by determining seasonal prey availability (electrofishing), analysis of undigested prey remains (spraints), and the use of stable isotopes (δ15N and δ13C) in otter spraints ( n = 262) and prey in a wetland ecosystem of southern Chile (39°49'S, 73°15'W). Fecal and isotopic analyses suggest that the otter diet is restricted to a few prey items, particularly the less-mobile, bottom-living, and larger prey such as crayfish ( Samastacus spinifrons, 86.11 %) and crabs ( Aegla spp., 32.45 %), supplemented opportunistically by cyprinids ( Cyprinus carpio, 9.55 %) and catfish ( Diplomystes camposensis, 5.66 %). The results suggest that the river otter is highly specialized in bottom foraging. Isotopic signatures of food sources and feces revealed a mid-upper trophic position for the Southern river otter, with either higher or lower δ15N values than their potential prey items. δ13C values for river otters were less enriched than their potential food resources. We suggest that due to their narrow trophic niche and possible dependence on only a few food items, this species may be highly vulnerable to the reduction in its prey populations. Finally, maintaining the ecological interactions between Southern river otters and their prey is considered a central priority for the survival of this endangered carnivore mammal.

Bilateral uric acid nephrolithiasis and ureteral hypertrophy in a free-ranging river otter (Lontra canadensis)

USGS Publications Warehouse

Grove, Robert A.; Bildfell, Rob; Henny, Charles J.; Buhler, D.R.

2003-01-01

We report the first case of uric acid nephrolithiasis in a free-ranging river otter (Lontra canadensis). A 7 yr old male river otter collected from the Skagit River of western Washington (USA) had bilateral nephrolithiasis and severely enlarged ureters (one of 305 examined [0.33%]). The uroliths were 97% uric acid and 3% protein. Microscopic changes in the kidney were confined to expansion of renal calyces, minor loss of medullary tissue, and multifocal atrophy of the cortical tubules. No inflammation was observed in either kidney or the ureters. The ureters were enlarged due to marked hypertrophy of smooth muscle plus dilation of the lumen. Fusion of the major calyces into a single ureteral lumen was several cm distal to that of two adult male otters used as histopathologic control specimens. This case report is part of a large contaminant study of river otters collected from Oregon and Washington. It is important to understand diseases and lesions of the otter as part of our overall evaluation of this population.

An update on Sarcocystis neurona infections in animals and Equine Protozoal Myeloencephalitis (EPM)

PubMed Central

Dubey, J. P.; Howe, D. K.; Furr, M.; Saville, W. J.; Marsh, A.E.; Reed, S. M.; Grigg, M. E.

2015-01-01

Equine protozoal myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treatment and control. PMID:25737052

An update on Sarcocystis neurona infections in animals and equine protozoal myeloencephalitis (EPM).

PubMed

Dubey, J P; Howe, D K; Furr, M; Saville, W J; Marsh, A E; Reed, S M; Grigg, M E

2015-04-15

Equine protozoal myeloencephalitis (EPM) is a serious disease of horses, and its management continues to be a challenge for veterinarians. The protozoan Sarcocystis neurona is most commonly associated with EPM. S. neurona has emerged as a common cause of mortality in marine mammals, especially sea otters (Enhydra lutris). EPM-like illness has also been recorded in several other mammals, including domestic dogs and cats. This paper updates S. neurona and EPM information from the last 15 years on the advances regarding life cycle, molecular biology, epidemiology, clinical signs, diagnosis, treatment and control. Published by Elsevier B.V.

Estimated ground-water use in Becker, Clay, Douglas, Grant, Otter Tail, and Wilkin Counties, Minnesota, for 2030 and 2050

USGS Publications Warehouse

Winterstein, Thomas A.

2007-01-01

The estimated recharge to the Buffalo aquifer, Otter Tail surficial aquifer, and Pelican River sand-plain aquifer is 3,707, 51,000, and 4,900–8,900 Mgal/yr, respectively. The range of the estimated 2050 ground-water withdrawals from the Buffalo, Otter Tail surficial, and Pelican River sand-plain aquifers is 1,234–1,776 Mgal/yr from the Buffalo aquifer, 11,728–14,820 Mgal/yr from the Otter Tail surficial aquifer, and 3,385–4,298 Mgal/yr from the Pelican River sand-plain aquifer.

Transformation of the genital epithelial tract occurs early in California sea lion development

PubMed Central

Barragán-Vargas, Cecilia; Montano-Frías, Jorge; Ávila Rosales, Germán; Godínez-Reyes, Carlos R.; Acevedo-Whitehouse, Karina

2016-01-01

An unusually high prevalence of metastatic urogenital carcinoma has been observed in free-ranging California sea lions stranded off the coast of California in the past two decades. No cases have been reported for sea lions in the relatively unpolluted Gulf of California. We investigated occurrence of genital epithelial transformation in 60 sea lions (n=57 pups and 3 adult females) from the Gulf of California and examined whether infection by a viral pathogen previously found to be associated with urogenital carcinoma accounted for such alterations. We also explored the contribution of MHC class II gene expression on transformation. Cellular alterations, such as squamous cell atypia (ASC), atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesions were observed in 42% of the pups and in 67% of the adult females. Normal genital epithelium was more common in male than female pups. ASC was five times more likely to occur in older pups. Epithelial alterations were unrelated to infection by the potentially oncogenic otarine type I gammaherpesvirus (OtHV-1), but ASCUS was more common in pups with marked and severe inflammation. Expression of MHC class II DRB loci (Zaca DRB-D) by peripheral antigen-presenting leucocytes showed a slightly ‘protective’ effect for ASC. We propose that transformation of the California sea lion genital epithelium is relatively common in young animals, increases with age and is probably the result of infection by an unidentified pathogen. Expression of a specific MHC class II gene, suggestive of presentation of specific antigenic peptides to immune effectors, appears to lower the risk of transformation. Our study provides the first evidence that epithelial transformation of the California sea lion genital tract is relatively common, even from an early age, and raises questions regarding differences in sea lion cancer-detection and -repair success between geographical regions. PMID:27069641

Earth observation taken by the Expedition 35 crew

NASA Image and Video Library

2013-04-23

ISS035-E-027431 (23 April 2013) --- This oblique Expedition 35 image from the International Space Station shows parts of Mexico, California and Nevada. The Los Angeles Basin can be easily delineated at left center. If the nomenclature for the body of water in the upper right quadrant of the image were the subject of a trivia question, the answer might be "all the above," as it is recognized by a number of names. They include the Gulf of California, Sea of Cortez, Sea of Cortes, Vermilion Sea as well as its local designations in the Spanish language as Mar de Cortes or Mar Bermejo or Golfo de California. It serves to separate the Baja California Peninsula from the Mexican mainland. It is bordered by the states of Baja California, Baja California Sur, Sonora, and Sinaloa (some of which are out of the frame) with a coastline of approximately 4,000 kilometers (2,500 miles). Rivers which flow into the Gulf of California include the Colorado, Fuerte, Mayo, Sinaloa, Sonora and the Yaqui. The gulf's surface area is about 160,000 square kilometers (62,000 square miles). A mass of clouds sits just off the Pacific coast of Baja California and southern California.

33 CFR 334.855 - Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation...

Code of Federal Regulations, 2014 CFR

2014-07-01

..., Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.855 Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. (a...

33 CFR 334.855 - Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation...

Code of Federal Regulations, 2012 CFR

2012-07-01

..., Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.855 Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. (a...

33 CFR 334.855 - Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation...

Code of Federal Regulations, 2011 CFR

2011-07-01

..., Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.855 Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. (a...

33 CFR 334.855 - Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation...

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.855 Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. (a...

33 CFR 334.855 - Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation...

Code of Federal Regulations, 2013 CFR

2013-07-01

..., Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.855 Salt River, Rolling Fork River, Otter Creek; U.S. Army Garrison, Fort Knox Military Reservation; Fort Knox, Kentucky; danger zone. (a...

Concentration and retention of Toxoplasma gondii oocysts by marine snails demonstrate a novel mechanism for transmission of terrestrial zoonotic pathogens in coastal ecosystems

USGS Publications Warehouse

Krusor, Colin; Smith, Woutrina A.; Tinker, M. Tim; Silver, Mary; Conrad, Patricia A.; Shapiro, Karen

2015-01-01

The parasite Toxoplasma gondii is an environmentally persistent pathogen that can cause fatal disease in humans, terrestrial warm-blooded animals and aquatic mammals. Although an association between T. gondii exposure and prey specialization on marine snails was identified in threatened California sea otters, the ability of kelp-dwelling snails to transmit terrestrially derived pathogens has not been previously investigated. The objective of this study was to measure concentration and retention of T. gondii by marine snails in laboratory aquaria, and to test for natural T. gondii contamination in field-collected snails. Following exposure to T. gondii-containing seawater, oocysts were detected by microscopy in snail faeces and tissues for 10 and 3 days respectively. Nested polymerase chain reaction was also applied as a method for confirming putative T. gondii oocysts detected in snail faeces and tissues by microscopy. Toxoplasma gondiiwas not detected in field-collected snails. Results suggest that turban snails are competent transport hosts for T. gondii. By concentrating oocysts in faecal pellets, snails may facilitate entry of T. gondii into the nearshore marine food web. This novel mechanism also represents a general pathway by which marine transmission of terrestrially derived microorganisms can be mediated via pathogen concentration and retention by benthic invertebrates.

Estimating occupancy and abundance using aerial images with imperfect detection

USGS Publications Warehouse

Williams, Perry J.; Hooten, Mevin B.; Womble, Jamie N.; Bower, Michael R.

2017-01-01

Species distribution and abundance are critical population characteristics for efficient management, conservation, and ecological insight. Point process models are a powerful tool for modelling distribution and abundance, and can incorporate many data types, including count data, presence-absence data, and presence-only data. Aerial photographic images are a natural tool for collecting data to fit point process models, but aerial images do not always capture all animals that are present at a site. Methods for estimating detection probability for aerial surveys usually include collecting auxiliary data to estimate the proportion of time animals are available to be detected.We developed an approach for fitting point process models using an N-mixture model framework to estimate detection probability for aerial occupancy and abundance surveys. Our method uses multiple aerial images taken of animals at the same spatial location to provide temporal replication of sample sites. The intersection of the images provide multiple counts of individuals at different times. We examined this approach using both simulated and real data of sea otters (Enhydra lutris kenyoni) in Glacier Bay National Park, southeastern Alaska.Using our proposed methods, we estimated detection probability of sea otters to be 0.76, the same as visual aerial surveys that have been used in the past. Further, simulations demonstrated that our approach is a promising tool for estimating occupancy, abundance, and detection probability from aerial photographic surveys.Our methods can be readily extended to data collected using unmanned aerial vehicles, as technology and regulations permit. The generality of our methods for other aerial surveys depends on how well surveys can be designed to meet the assumptions of N-mixture models.

Sink or swim? Bone density as a mechanism for buoyancy control in early cetaceans.

PubMed

Gray, Noel-Marie; Kainec, Kimberly; Madar, Sandra; Tomko, Lucas; Wolfe, Scott

2007-06-01

Previous analyses have shown that secondarily aquatic tetrapods, including whales, exhibit osteological adaptations to life in water as part of their complex buoyancy control systems. These structural specializations of bone span hyperostosis through osteoporosis. The past 15 years of paleontological effort has provided an unprecedented opportunity to examine the osteological transformation of whales as they make their transition to an obligate aquatic lifestyle over a 10-million-year period. It is hypothesized that whales manifest their osteological specialization in the same manner as extant semiaquatic and fully aquatic mammals. This study presents and analysis of the microstructural features of bone in early and late archaic cetaceans, and in a comparative sample of modern terrestrial, semiaquatic, and aquatic mammals. Bone histology was examined from the ribs of 10 fossilized individuals representing five early cetacean families, including Pakicetidae, Ambulocetidae, Protocetidae, Remintonocetidae, and Basilosauridae. Comparisons were then made with rib histology from nine genera of extant mammals including: Odocoileus (deer), Bos (cow), Equus (horse), Canis (dog), Lutra (river otter), Enhydra (sea otter), Choeropsis (pygmy hippo), Trichechus (sea cow), and Delphinus (dolphin). Results show that the transition from terrestrial, to semiaquatic, to obligate aquatic locomotion in archaeocetes involved a radical shift in bone function achieved by means of profound changes at the microstructural level. A surprising finding was that microstructural change predates gross anatomical shift in archaeocetes associated with swimming. Histological analysis shows that high bone density is an aquatic specialization that provides static buoyancy control (ballast) for animals living in shallow water, while low bone density is associated with dynamic buoyancy control for animals living in deep water. Thus, there was a shift from the typical terrestrial form, to osteopetrosis and pachyosteosclerosis, and then to osteoporosis in the first quarter of cetacean evolutionary history. 2007 Wiley-Liss, Inc.

Using demography and movement behavior to predict range expansion of the southern sea otter.

USGS Publications Warehouse

Tinker, M.T.; Doak, D.F.; Estes, J.A.

2008-01-01

In addition to forecasting population growth, basic demographic data combined with movement data provide a means for predicting rates of range expansion. Quantitative models of range expansion have rarely been applied to large vertebrates, although such tools could be useful for restoration and management of many threatened but recovering populations. Using the southern sea otter (Enhydra lutris nereis) as a case study, we utilized integro-difference equations in combination with a stage-structured projection matrix that incorporated spatial variation in dispersal and demography to make forecasts of population recovery and range recolonization. In addition to these basic predictions, we emphasize how to make these modeling predictions useful in a management context through the inclusion of parameter uncertainty and sensitivity analysis. Our models resulted in hind-cast (1989–2003) predictions of net population growth and range expansion that closely matched observed patterns. We next made projections of future range expansion and population growth, incorporating uncertainty in all model parameters, and explored the sensitivity of model predictions to variation in spatially explicit survival and dispersal rates. The predicted rate of southward range expansion (median = 5.2 km/yr) was sensitive to both dispersal and survival rates; elasticity analysis indicated that changes in adult survival would have the greatest potential effect on the rate of range expansion, while perturbation analysis showed that variation in subadult dispersal contributed most to variance in model predictions. Variation in survival and dispersal of females at the south end of the range contributed most of the variance in predicted southward range expansion. Our approach provides guidance for the acquisition of further data and a means of forecasting the consequence of specific management actions. Similar methods could aid in the management of other recovering populations.

Scale-dependent factors affecting North American river otter distribution in the midwest

USGS Publications Warehouse

Jeffress, Mackenzie R.; Paukert, C.P.; Whittier, Joanna B.; Sandercock, B.K.; Gipson, P.S.

2011-01-01

The North American river otter (Lontra canadensis) is recovering from near extirpation throughout much of its range. Although reintroductions, trapping regulations and habitat improvements have led to the reestablishment of river otters in the Midwest, little is known about how their distribution is influenced by local- and landscape-scale habitat. We conducted river otter sign surveys from Jan. to Apr. in 2008 and 2009 in eastern Kansas to assess how local- and landscape-scale habitat factors affect river otter occupancy. We surveyed three to nine 400-m stretches of stream and reservoir shorelines for 110 sites and measured local-scale variables (e.g., stream order, land cover types) within a 100 m buffer of the survey site and landscape-scale variables (e.g., road density, land cover types) for Hydrological Unit Code 14 watersheds. We then used occupancy models that account for the probability of detection to estimate occupancy as a function of these covariates using Program PRESENCE. The best-fitting model indicated river otter occupancy increased with the proportion of woodland cover and decreased with the proportion of cropland and grassland cover at the local scale. Occupancy also increased with decreased shoreline diversity, waterbody density and stream density at the landscape scale. Occupancy was not affected by land cover or human disturbance at the landscape scale. Understanding the factors and scale important to river otter occurrence will be useful in identifying areas for management and continued restoration. ?? 2011, American Midland Naturalist.

Variability within nearshore ecosystems of the Gulf of Alaska

USGS Publications Warehouse

Ballachey, Brenda E.; Bodkin, James L.; Coletti, Heather A.; Dean, Thomas A; Esler, Daniel N.; Esslinger, George G.; Iken, Katrin; Kloecker, Kimberly A.; Konar, Brenda; Lindeberg, Mandy; Monson, Daniel; Shepherd, Marnie; Weitzman, Ben P.

2015-01-01

Nearshore marine habitats, which represent the interface among air, land and sea, form a critical component of the Gulf of Alaska (GOA) ecosystem. As an interface, the nearshore facilitates transfer of water, nutrients and biota between terrestrial and oceanic systems, creating zones of high productivity. The nearshore provides a variety of ecosystem services, including (1) nursery grounds for a wide variety of marine invertebrates and fishes (e.g., crabs, salmon, and herring), (2) nesting and pupping habitats for many pelagic marine predators (e.g., sea bird nesting colonies and pinniped rookeries), (3) important feeding habitats for high trophic level pelagic predators (e.g., killer whales), (4) habitat for resident nearshore species (including sea otters, harbor seals, shorebirds, sea ducks, nearshore fishes, and marine invertebrates), many of which are important sources of commercial and subsistence harvests, and (5) recreational, commercial and subsistence opportunities for human populations (Figure 1-1). The canopy forming kelps and eel grass beds found in the nearshore provide primary production and structure to nursery habitats, and also can dissipate wave energy thus reducing coastal erosion, and serve as a carbon “sink” capable of storing substantial amounts of atmospheric CO2 (Wilmers et al. 2012).

75 FR 27847 - Broadengate Systems, Inc., (n/k/a Otter Lake Resources, Inc.); Order of Suspension of Trading

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-18

... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] Broadengate Systems, Inc., (n/k/a Otter Lake... Systems, Inc. (n/k/a Otter Lake Resources, Inc.) because it has not filed any periodic reports since the.... Therefore, it is ordered, pursuant to Section 12(k) of the Securities Exchange Act of 1934, that trading in...

The Conservation Knowledge and Attitudes of Teenagers in Slovenia toward the Eurasian Otter

ERIC Educational Resources Information Center

Torkar, Gregor; Mohar, Petra; Gregorc, Tatjana; Nekrep, Igor; Adamic, Marjana Honigsfeld

2010-01-01

This study focused on human-otter interactions in Slovenia. The aim of the study was to obtain data about secondary-school students' knowledge of and attitudes toward the Eurasian otter (Lutra lutra) and its conservation. The survey was carried out in fall 2008 and winter 2008-09 and included 273 teenagers. Their average age was 15.57 (SD = 1.01,…

50 CFR 23.69 - How can I trade internationally in fur skins and fur skin products of bobcat, river otter, Canada...

Code of Federal Regulations, 2014 CFR

2014-10-01

... skins and fur skin products of bobcat, river otter, Canada lynx, gray wolf, and brown bear harvested in... trade internationally in fur skins and fur skin products of bobcat, river otter, Canada lynx, gray wolf... lynx (Lynx canadensis), gray wolf (Canis lupus), and brown bear (Ursus arctos) harvested in the United...

Prevalence of Urogenital Carcinoma in Stranded California Sea Lions ( Zalophus Californianus) from 2005-2015.

PubMed

Deming, Alissa C; Colegrove, Kathleen M; Duignan, Padraig J; Hall, Ailsa J; Wellehan, James F X; Gulland, Frances M D

2018-03-02

Urogenital carcinoma is common in wild California sea lions ( Zalophus californianus) along the west coast of the US. From 1979 to 1994, this cancer was observed in 18% (66/370) of necropsied subadult and adult sea lions at The Marine Mammal Center in Sausalito, California. A retrospective review of records from 1 January 2005 to 31 December 2015 was performed to characterize prevalence and characteristics of cancer over this decade. Fourteen percent (263/1917) of necropsied sea lions had cancer, of which 90% (237/263) were urogenital carcinoma. The prevalence of urogenital carcinoma was significantly higher in adults compared to juveniles and subadults. Advanced-stage disease with metastases was identified histologically in 78% (182/232) of cases and was the cause of death in 95% (172/182) of these cases. Metastases were most common in lung and lymph nodes, and hydronephrosis, secondary to ureter obstruction by metastases, was identified in 62% (114/185) of animals with advanced disease. No significant temporal change in prevalence was detected over the decade, and this highly aggressive, fatal cancer remains common in stranded California sea lions.

University of California Sea Grant College Program Directory 1974-1975.

ERIC Educational Resources Information Center

California Univ., San Diego, La Jolla. Inst. of Marine Resources.

The directory provides detailed information on the University of California Sea Grant programs dealing with management, education, and advisory services; coastal resources; agricultural research and development; fisheries research and development; as well as energy resources and development. (NTIS)

STRESS LEVELS IN CAPTURED RIVER OTTERS (LONTRA CANADENSIS) DECREASED AFTER TRANSPORTATION TO REINTRODUCTION SITES.

PubMed

Taylor, Rebekah T; Wong, Jennifer A; Serfass, Thomas L

2016-12-01

The level of stress that animals endure during capture, handling, transportation, and release processes is a major concern of animal reintroduction projects. Animals under chronic stress are more susceptible to disease and other deleterious issues that could reduce their survival in a new environment. Northern river otters ( Lontra canadensis ) have been reintroduced in 22 states in the United States and may be susceptible to developing chronic stress during the reintroduction process. We assessed stress levels in five river otters captured from wild populations in Washington, held in captivity for up to 21 days, and then transported to New Mexico for reintroduction. Glucocorticoid levels in fecal samples of all otters tested decreased from when they were held captive in Washington to the time of release. This outcome suggests that habituation to captivity before transport and release may serve to minimize the likelihood of an otter being released while experiencing a potentially burdensome level of stress.

Surgical implantation of intra-abdominal radiotransmitters in marine otters (Lontra felina) in central Chile.

PubMed

Soto-Azat, Claudio; Boher, Francisca; Fabry, Mauricio; Pascual, Paulo; Medina-Vogel, Gonzalo

2008-10-01

Six free-ranging marine otters (Lontra felina) were livetrapped on the central coast of Chile and implanted with specially designed radiotransmitters as part of a spatial ecology study. Marine otters frequent the rocky seashore, often squeezing their narrow bodies through cracks and crevices and grooming themselves on the rocks. They are also among the smallest of the otter species, weighing between 3.4 kg and 4.5 kg. For these reasons, the transmitter used was small, rectangular, and flat, measuring 3.5 x 3.2 x 1.0 cm. They were implanted using a ventral midline approach to minimize contact between the skin incision and sharp-edged rocks. Surgical incisions healed within 2 wk. The transmitters functioned well, but the duration varied from 62 days to 143 days instead of the 240 days predicted by the manufacturer. All six marine otters reestablished in their home ranges, and survey results suggest they survived well beyond the life of the transmitters.

Pinniped Hearing in Complex Acoustic Environments

DTIC Science & Technology

2013-09-30

published] Mulsow, J. & Reichmuth, C. (2013). The binaural click-evoked auditory brainstem response of the California sea lion (Zalophus...California sea lion can keep the beat : Motor entrainment to rhythmic auditory stimuli in a non vocal mimic. Journal of Comparative Psychology, online first. [published

NAE Twin Otter operations in FIFE 1989

NASA Technical Reports Server (NTRS)

Macpherson, J. I.

1990-01-01

During the summer of 1989, the National Aeronautical Establishment (Canada) Twin Otter Atmospheric Research Aircraft was flow in support of the NASA sponsored First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment called FIFE-89. Airborne measurements of the fluxes of heat, momentum, water vapor and carbon dioxide were made during 16 flow-altitude flights over the FIFE project area in central Kansas. The Twin Otter operations in FIFE are documented and details are included on the instrumentation, software, flight procedures, atmospheric conditions and analysis methods. Comparisons of Twin Otter measured fluxes are made with those determined at several surface sites and with those made by other instrumented aircraft in the FIFE-87 measurements. Airborne flux measurements are related to run length, altitude, and environmental parameters such as vegetation type, temperature, and wind speed. One night flight was run in an attempt to measure the respiration component of the CO2 flux. The use of aircraft was studied for regional observations of fluxes and to relate these to satellite radiance measurements. Run average data are presented for all 285 flux runs flown by the Twin Otter in FIFE-89. This should serve as as a working reference for scientists utilizing Twin Otter data either directly of through the FIFE data archive.

Predicting Trophic Interactions and Habitat Utilization in the California Current Ecosystem

DTIC Science & Technology

2014-09-30

on trophic interactions affecting habitat utilization and foraging patterns of California sea lions (CSL) in the California Current Large Marine...middle (sardine and anchovy) and higher (sea lions ) trophic level species. To this end, our numerical experiments are designed to isolate patterns of...NEMURO) embedded in a regional ocean circulation model (ROMS), and both coupled with a multi- species individual-based model (IBM) for forage fish

Data management for support of the Oregon Transect Ecosystem Research (OTTER) project

NASA Technical Reports Server (NTRS)

Skiles, J. W.; Angelici, Gary L.

1993-01-01

Management of data collected during projects that involve large numbers of scientists is an often overlooked aspect of the experimental plan. Ecosystem science projects like the Oregon Transect Ecosystem Research (OTTER) Project that involve many investigators from many institutions and that run for multiple years, collect and archive large amounts of data. These data range in size from a few kilobytes of information for such measurements as canopy chemistry and meteorological variables, to hundreds of megabytes of information for such items as views from multi-band spectrometers flown on aircraft and scenes from imaging radiometers aboard satellites. Organizing and storing data from the OTTER Project, certifying those data, correcting errors in data sets, validating the data, and distributing those data to other OTTER investigators is a major undertaking. Using the National Aeronautics and Space Administration's (NASA) Pilot Land Data System (PLDS), a Support mechanism was established for the OTTER Project which accomplished all of the above. At the onset of the interaction between PLDS and OTTER, it was not certain that PLDS could accomplish these tasks in a manner that would aid researchers in the OTTER Project. This paper documents the data types that were collected under the auspices of the OTTER Project and the procedures implemented to store, catalog, validate, and certify those data. The issues of the compliance of investigators with data-management requirements, data use and certification, and the ease of retrieving data are discussed. We advance the hypothesis that formal data management is necessary in ecological investigations involving multiple investigators using many data gathering instruments and experimental procedures. The issues and experience gained in this exercise give an indication of the needs for data management systems that must be addressed in the coming decades when other large data-gathering endeavors are undertaken by the ecological science community.

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

USGS Publications Warehouse

Williams, Perry J.; Hooten, Mevin B.; Womble, Jamie N.; Esslinger, George G.; Bower, Michael R.; Hefley, Trevor J.

2017-01-01

Ecological invasions and colonizations occur dynamically through space and time. Estimating the distribution and abundance of colonizing species is critical for efficient management or conservation. We describe a statistical framework for simultaneously estimating spatiotemporal occupancy and abundance dynamics of a colonizing species. Our method accounts for several issues that are common when modeling spatiotemporal ecological data including multiple levels of detection probability, multiple data sources, and computational limitations that occur when making fine-scale inference over a large spatiotemporal domain. We apply the model to estimate the colonization dynamics of sea otters (Enhydra lutris) in Glacier Bay, in southeastern Alaska.

STS-49 Earth observation of the Salton Sea and the Gulf of California

NASA Technical Reports Server (NTRS)

1992-01-01

STS-49 Earth observation taken aboard Endeavour, Orbiter Vehicle (OV) 105, shows the Salton Sea and the Gulf of California. The nearly cloud-free view follows the Colorado River Delta from the Gulf of California (Mexico) to the Salton Sea (California). The Colorado River enters its delta from the right (east), then turns directly south to form saline tidal flats at the edge of the gulf. Nearly all the water is used for irrigation. The United States (U.S.) / Mexican border shows clearly in the different field patterns and the intensity of the greenish color. The irrigated agricultural area offers a sharp contrast to the surrounding desert. The crew used a handheld HASSELBLAD camera with a 100-mm lens to record the image.

Phylogenomic characterization of California sea lion adenovirus-1.

PubMed

Cortés-Hinojosa, Galaxia; Gulland, Frances M D; Goldstein, Tracey; Venn-Watson, Stephanie; Rivera, Rebecca; Waltzek, Thomas B; Salemi, Marco; Wellehan, James F X

2015-04-01

Significant adenoviral diversity has been found in humans, but in domestic and wild animals the number of identified viruses is lower. Here we present the complete genome of a recently discovered mastadenovirus, California sea lion adenovirus 1 (CSLAdV-1) isolated from California sea lions (Zalophus californianus), an important pathogen associated with hepatitis in pinnipeds. The genome of this virus has the typical mastadenoviral structure with some notable differences at the carboxy-terminal end, including a dUTPase that does not cluster with other mastadenoviral dUTPases, and a fiber that shows similarity to a trans-sialidase of Trypanosoma cruzi and choline-binding protein A (CbpA) of Streptococcus pneumoniae. The GC content is low (36%), and phylogenetic analyses placed the virus near the root of the clade infecting laurasiatherian hosts in the genus Mastadenovirus. These findings support the hypothesis that CSLAdV-1 in California sea lions represents a host jump from an unknown mammalian host in which it is endemic. Copyright © 2015 Elsevier B.V. All rights reserved.

Sea-floor gouges caused by migrating gray whales off northern California

USGS Publications Warehouse

Cacchione, D.A.; Drake, D.E.; Field, M.E.; Tate, G.B.

1987-01-01

Side-scan sonar records collected during March and April 1981 and 1982 off northern California contain elongate depressions whose sizes and shapes are similar to sea-floor gouges made by feeding gray whales (Eschrichtius robustus) in the northern Bering Sea and in shallow embayments off British Columbia. The discovery of the whale gouges in the sonar records was unexpected, and supports some of the previous speculation that gray whales feed opportunistically during migration. Gouges occupy about 0.032% of the 7.6 km2 of sea floor that was surveyed, which represents about 575 metric tons of excavated material. Although seemingly minor in amount, the total amount of bottom sediment removed from the central and northern California continental shelf by gray whale activities year after year represents macroscale biologically induced erosion and could have significant geological implications in shelf erosion and depositional schemes. This is the only published evidence of benthic feeding by gray whales along their migration route off northern California. ?? 1987.

Clinical relevance of novel Otarine herpesvirus-3 in California sea lions (Zalophus californianus): lymphoma, esophageal ulcers, and strandings

PubMed Central

2012-01-01

Herpesviruses have been recognized in marine mammals, but their clinical relevance is not always easy to assess. A novel otarine herpesvirus-3 (OtHV3) was detected in a geriatric California sea lion (Zalophus californianus), and using a newly developed quantitative PCR assay paired with histology, OtHV3 was associated with esophageal ulcers and B cell lymphoblastic lymphoma in this animal. The prevalence and quantities of OtHV3 were then determined among buffy coats from 87 stranded and managed collection sea lions. Stranded sea lions had a higher prevalence of OtHV3 compared to managed collection sea lions (34.9% versus 12.5%; p = 0.04), and among the stranded sea lions, yearlings were most likely to be positive. Future epidemiological studies comparing the presence and viral loads of OtHV3 among a larger population of California sea lions with and without lymphoid neoplasia or esophageal ulcers would help elucidate the relevance of OtHV3-associated pathologies to these groups. PMID:23234600

Projecting future sea level

USGS Publications Warehouse

Cayan, Daniel R.; Bromirski, Peter; Hayhoe, Katharine; Tyree, Mary; Dettinger, Mike; Flick, Reinhard

2006-01-01

California’s coastal observations and global model projections indicate that California’s open coast and estuaries will experience increasing sea levels over the next century. Sea level rise has affected much of the coast of California, including the Southern California coast, the Central California open coast, and the San Francisco Bay and upper estuary. These trends, quantified from a small set of California tide gages, have ranged from 10–20 centimeters (cm) (3.9–7.9 inches) per century, quite similar to that estimated for global mean sea level. So far, there is little evidence that the rate of rise has accelerated, and the rate of rise at California tide gages has actually flattened since 1980, but projections suggest substantial sea level rise may occur over the next century. Climate change simulations project a substantial rate of global sea level rise over the next century due to thermal expansion as the oceans warm and runoff from melting land-based snow and ice accelerates. Sea level rise projected from the models increases with the amount of warming. Relative to sea levels in 2000, by the 2070–2099 period, sea level rise projections range from 11–54 cm (4.3–21 in) for simulations following the lower (B1) greenhouse gas (GHG) emissions scenario, from 14–61 cm (5.5–24 in) for the middle-upper (A2) emission scenario, and from 17–72 cm (6.7–28 in) for the highest (A1fi) scenario. In addition to relatively steady secular trends, sea levels along the California coast undergo shorter period variability above or below predicted tide levels and changes associated with long-term trends. These variations are caused by weather events and by seasonal to decadal climate fluctuations over the Pacific Ocean that in turn affect the Pacific coast. Highest coastal sea levels have occurred when winter storms and Pacific climate disturbances, such as El Niño, have coincided with high astronomical tides. This study considers a range of projected future global sea level rises in examining possible impacts at California coastal and estuarine stations. Two climate models and three scenarios considered in this scenarios study provide a set of possible future weather and short-period climate fluctuations, and a range of potential long-term sea level rise values. A range of mean sea level rise was considered in combination with weather and El Niño fluctuations extracted from two global climate models and two GHG emissions scenarios. The mean sea level rise values, determined from a survey of several climate models, range from approximately 10–80 cm (3.9–31 in) between 2000 and 2100. The middle to higher end of this range would substantially exceed the historical rate of sea level rise of 15–20 cm (5.9–7.9 in)per century observed at San Francisco and San Diego during the last 100 years. Gradual sea level rise progressively worsens the impacts of high tides and the surge and waves associated with storms. The potential for impacts of future sea level rise was assessed from the occurrence of hourly sea level extremes. The occurrence of extreme events follows a sharply escalating pattern as the magnitude of future sea level rise increases. The confluence of Low barometric pressures from storms and the presence large waves at the same time substantially increases the likelihood of high, damaging sea levels along the California coast. Similarly, astronomical tides and disturbances in sea level that are caused by weather and climate fluctuations are x transmitted into the San Francisco Bay and Delta, and on into the lower reaches of the Sacramento River. In addition to elevating Bay and Delta sea levels directly through inverse barometer and wind effects, storms may generate heavy precipitation and high fresh water runoff and cause floods in the Sacramento/San Joaquin Delta, increasing the potential for inundation of levees and other structures. There may also be increased risk of levee failure due to the hydraulics and geometry of these structures. Rising sea levels from climate change will increase the frequency and duration of extreme high water levels, causing historical coastal and San Francisco Bay/Delta structure design criteria to be exceeded.

Sea Grant in California: Twenty Years of Achievement.

ERIC Educational Resources Information Center

Amidei, Rosemary

Since 1968, the California Sea Grant program has operated to produce scientific research oriented to solving problems in marine resource development, management, and conservation. This document decribes the facets of this program, their accomplishments and goals. Discussions include: (1) historical notes; (2) coastal governance; (3) coastal…

Food limitation of sea lion pups and the decline of forage off central and southern California

PubMed Central

McClatchie, Sam; Field, John; Thompson, Andrew R.; Gerrodette, Tim; Lowry, Mark; Fiedler, Paul C.; Watson, William; Nieto, Karen M.; Vetter, Russell D.

2016-01-01

California sea lions increased from approximately 50 000 to 340 000 animals in the last 40 years, and their pups are starving and stranding on beaches in southern California, raising questions about the adequacy of their food supply. We investigated whether the declining sea lion pup weight at San Miguel rookery was associated with changes in abundance and quality of sardine, anchovy, rockfish and market squid forage. In the last decade off central California, where breeding female sea lions from San Miguel rookery feed, sardine and anchovy greatly decreased in biomass, whereas market squid and rockfish abundance increased. Pup weights fell as forage food quality declined associated with changes in the relative abundances of forage species. A model explained 67% of the variance in pup weights using forage from central and southern California and 81% of the variance in pup weights using forage from the female sea lion foraging range. A shift from high to poor quality forage for breeding females results in food limitation of the pups, ultimately flooding animal rescue centres with starving sea lion pups. Our study is unusual in using a long-term, fishery-independent dataset to directly address an important consequence of forage decline on the productivity of a large marine predator. Whether forage declines are environmentally driven, are due to a combination of environmental drivers and fishing removals, or are due to density-dependent interactions between forage and sea lions is uncertain. However, declining forage abundance and quality was coherent over a large area (32.5–38° N) for a decade, suggesting that trends in forage are environmentally driven. PMID:27069651

Interaction of extender composition and freezing method for effective semen cryopreservation in the North American river otter (Lontra canadensis).

PubMed

Bateman, Helen L; Swanson, William F

2017-10-01

Semen cryopreservation and storage in genome resource banks (GRBs), in combination with artificial insemination (AI), could be invaluable for genetic management and conservation of endangered otter species. For any applied conservation benefit, effective methods for otter sperm processing and cryopreservation first must be established. In this study, our objective was to develop an effective semen cryopreservation method for the North American river otter, evaluating the effect of extender composition (i.e., glycerol concentration, Equex STM paste supplementation) and freezing protocol (timing of glycerol addition, pre-freeze cooling rate, freezing/packaging method) on post-thaw sperm motility, longevity and acrosome status. Semen was collected from 14 otters housed at 9 zoos, and following cryopreservation in an egg-yolk based extender, thawed to assess sperm motility and acrosome status immediately post-thaw and during 6 h of in vitro culture. Results indicated that extender containing 4% glycerol was preferable (p < 0.05) to 8% glycerol but the temperature/timing of extender addition containing 4% glycerol did not affect (p > 0.05) post-thaw sperm parameters. Treatments with extender containing Equex and frozen by pelleting on dry ice showed greater (p < 0.05) motility and percentage of intact acrosomes compared to treatments frozen in extender without Equex, regardless of pre-freeze cooling rate. In the absence of Equex, pelleting provided superior post-thaw sperm motility (p < 0.01) and higher (p < 0.001) percentage of sperm with intact acrosomes compared to samples frozen in straws over liquid nitrogen vapor. Results of this study indicate that cryopreservation of otter sperm using an egg-yolk -TEST based extender containing 4% glycerol and 1% Equex, with the pellet freezing method, provided superior post-thaw sperm motility, longevity and acrosomal integrity compared to other combinations. Neither alterations in timing of glycerolated extender addition nor pre-freeze cooling rate had a discernable effect on post-thaw otter sperm parameters. These findings represent the first assessment of semen cryopreservation in any otter species and may be of value as a model for development of semen cryopreservation strategies in other endangered otter species. Copyright © 2017 Elsevier Inc. All rights reserved.

Hydrodynamic characteristics of the oval cambered double slotted otter board in bottom trawl fisheries

NASA Astrophysics Data System (ADS)

Liu, J.; Huang, H. L.; Li, L. Z.; Qu, T. C.; Wu, Y.; Chen, S.; Yang, J. L.; Rao, X.

2017-07-01

The otter board is one of the main components of single boat trawl fisheries. An oval cambered double slotted otter board was developed for improving the expansion performance of trawl net in bottom trawl fisheries. A flume model experiment was conducted to measure the lift coefficient (C L), drag coefficient (C D), and lift to drag ratio (K) in different angles of attack (α). The experimental results are as follows : (1) The C L and K value show a trend of increasing at the beginning and then decreasing with the increase of angle of attack, the C D value reflects an upward trend as the angle of attack increases; (2) The D3 otter board (front flow deflector angle at 29°) showed a better hydrodynamic performance. When α=30°, the max lift coefficient (C Lmax) was 1.464, in this case C D = 0.554 and K=2.643. When α=15°, the max lift to drag ratio (K max) was 4.165, C L =0.633, and C D = 0.152. This suggests that the best working scope for the angle of attack is between 15°~30°, in which case, C L>0.633 and K>2.643. The mean value of the lift coefficient was 1.071 and the mean of the lift to drag ratio was 3.482. Comparative analysis of the hydrodynamic performance of different types of otter boards showed that the D3 otter board both had good expansion performance and efficiency, which can provide a reference basis for further optimization of the bottom trawl otter board.

Chlorinated hydrocarbons in livers of American mink (Mustela vison) and river otter (Lutra canadensis) from the Columbia and Fraser River Basins, 1990-1992

USGS Publications Warehouse

Elliott, J.E.; Henny, Charles J.; Harris, M.L.; Wilson, L.K.; Norstrom, R.J.

1999-01-01

We investigated chlorinated hydrocarbon contaminants in aquatic mustelid species on the Fraser and Columbia Rivers of northwestern North America. Carcasses of river otter (Lutra canadensis) (N=24) and mink (Mustela vison) (N=34) were obtained from commercial trappers during the winters of 1990-91 and 1991a??92. Pooled liver samples were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), including non-ortho congeners, polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Most samples contained detectable concentrations of DDE, PCBs, although there was substantial variability in patterns and trends among neighboring samples. Concentrations of DDE were in some mink and several otter samples from the lower Columbia River elevated (to 4700 g/kg wet weight); excluding one mink sample from the Wenatchee area, mean DDE levels generally decreased between 1978a??79 and 1990a??92. PCBs were present in all samples. PCB concentrations in otter livers collected from the lower Columbia were ten-fold lower than measured a decade previously; nevertheless, a sample taken near Portland had a mean concentration of 1500 g/kg, within a range of concentrations associated with reproductive effects in captive mink. Concentrations of 2,3,7,8-TCDD and TCDF were generally below detection limits, except for one otter collected near a pulp mill at Castlegar, on the upper Columbia, with 11 ng TCDD/kg in liver. Elevated concentrations of higher chlorinated PCDD/Fs, probably resulting from use of chlorophenolic wood preservatives, were found in both species; one otter sample from the lower Columbia had 2200 ng OCDD/kg. International TCDD toxic equivalent levels in mink (31 ng/kg) and otter (93 ng/kg) from the lower Columbia River approached toxicity thresholds for effects on reproduction in ranch mink.

Asymptomatic and chronic carriage of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus)

USDA-ARS?s Scientific Manuscript database

Since 1970, periodic outbreaks of leptospirosis, caused by pathogenic spirochetes in the genus Leptospira, have caused morbidity and mortality of California sea lions (Zalophus californianus) along the Pacific coast of North America. Yearly seasonal epizootics of varying magnitude occur between the ...

REVIEW OF THE FISHERIES OF THE SALTON SEA, CALIFORNIA, USA: PAST, PRESENT, FUTURE. (R826552)

EPA Science Inventory

The Salton Sea is an endorheic, 980-km² salt lake in the Sonoran Desert of southern California. The historical fish community switched from freshwater to marine species as salinity increased due to evaporation and brackish water inflows. Three species, bairdiella (<...

Novel symptomatology and changing epidemiology of domoic acid toxicosis in California sea lions (Zalophus californianus): an increasing risk to marine mammal health

PubMed Central

Goldstein, T; Mazet, J.A.K; Zabka, T.S; Langlois, G; Colegrove, K.M; Silver, M; Bargu, S; Van Dolah, F; Leighfield, T; Conrad, P.A; Barakos, J; Williams, D.C; Dennison, S; Haulena, M; Gulland, F.M.D

2007-01-01

Harmful algal blooms are increasing worldwide, including those of Pseudo-nitzschia spp. producing domoic acid off the California coast. This neurotoxin was first shown to cause mortality of marine mammals in 1998. A decade of monitoring California sea lion (Zalophus californianus) health since then has indicated that changes in the symptomatology and epidemiology of domoic acid toxicosis in this species are associated with the increase in toxigenic blooms. Two separate clinical syndromes now exist: acute domoic acid toxicosis as has been previously documented, and a second novel neurological syndrome characterized by epilepsy described here associated with chronic consequences of previous sub-lethal exposure to the toxin. This study indicates that domoic acid causes chronic damage to California sea lions and that these health effects are increasing. PMID:18006409

New records of the deep-sea anemone Phelliactis callicyclus Riemann-Zurneck, 1973 (Cnidaria, Actiniaria, Hormathiidae) from the Gulf of California, Mexico.

PubMed

Hendrickx, M E; Hinojosa-Corona, A; Ayón-Parente, M

2016-10-20

Specimens of a deep-sea anemone were observed in photographs and video footage taken with the Remotely Operated Vehicle JASON (WHOI Deep Submergence Laboratory) in the Gulf of California, Mexico, in May 2008. Comparison of our material with photographs and description of this species available in literature indicate that the sea anemones filmed during the JASON survey are most likely to represent Phelliactis callicyclus Riemann-Zurneck, 1973. This species has previously been reported from a locality in the Gulf of California near the present record. During the JASON survey, 28 specimens of P. callicyclus were spotted in 27 locations during six dives. The specimens occurred on angular rock outcrops along the escarpments of the transform faults of the Gulf of California, between depths of 993-2543 m and at temperatures ranging from 2.3 to 4.5°C. Based on these new records, Phelliactis callicyclus appears to be widely spread in the Gulf of California.

Lidar Wind Profiler Comparison to Weather Balloon for Support of Orion Crew Exploration Vehicle Landings

NASA Technical Reports Server (NTRS)

Houtas, Franzeska F.; Teets, Edward H.

2010-01-01

A comparison study by the National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California) and the Naval Post Graduate School Center for Interdisciplinary Remotely-Piloted Aircraft Studies (Marina, California) was conducted to show the advantages of an airborne wind profiling light detection and ranging (lidar) system in reducing drift uncertainty along a reentry vehicle descent trajectory. This effort was in support of the once planned Orion Crew Exploration Vehicle ground landing. A Twin Otter Doppler Wind Lidar was flown on multiple flights along the approximate ground track of each ascending weather balloon launched from the Marina Municipal Airport (Marina, California). The airborne lidar used was a 5-mJ, 2-micron infrared laser with a 10-cm telescope and a two-axis scanner. Each lidar wind profile contains data for an altitude range between the surface and flight altitude of 2.7 km, processed on board every 20 s. In comparison, a typical weather balloon would traverse that same altitude range with a similar data set available in approximately 15 to 20 min. These tests were conducted on November 15 and 16, 2007. Results show a best-case absolute difference of 0.18 m/s (0.35 knots) in speed and 1 degree in direct

Chronic effects of the Exxon Valdez oil spill on blood and enzyme chemistry of river otters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duffy, L.K.; Bowyer, R.T.; Testa, J.W.

1994-04-01

River otters (Lutra canadensis) living in marine environments of Prince William Sound, Alaska, and exposed to crude oil from the Exxon Valdez spill in March 1989 showed elevated levels of blood haptoglobins, and interleukin-6 ir, as well as elevated activities of aspartate aminotransferase, alanine aminotransferase, and creatine kinase in summer 1991. Stepwise logistic regression, using a subset of these and other blood proteins and enzyme activities as potential independent variables, correctly classified 86.4% of 22 otters as inhabiting oiled or nonoiled areas. River otters abandoned latrine sites (an index to their abundance) over three times more often in oiled thanmore » in nonoiled areas, suggesting there may have been a delayed response in river otter populations to exposure to crude oil. This is the first clear model for the long-term effects of an oil spill on blood parameters of a free-ranging mammal using a nonlethal methodology. These effects occurred two years after the spill and following a major effort to clean oil from the shorelines of Prince William Sound.« less

Vocal repertoire of the social giant otter.

PubMed

Leuchtenberger, Caroline; Sousa-Lima, Renata; Duplaix, Nicole; Magnusson, William E; Mourão, Guilherme

2014-11-01

According to the "social intelligence hypothesis," species with complex social interactions have more sophisticated communication systems. Giant otters (Pteronura brasiliensis) live in groups with complex social interactions. It is likely that the vocal communication of giant otters is more sophisticated than previous studies suggest. The objectives of the current study were to describe the airborne vocal repertoire of giant otters in the Pantanal area of Brazil, to analyze call types within different behavioral contexts, and to correlate vocal complexity with level of sociability of mustelids to verify whether or not the result supports the social intelligence hypothesis. The behavior of nine giant otters groups was observed. Vocalizations recorded were acoustically and statistically analyzed to describe the species' repertoire. The repertoire was comprised by 15 sound types emitted in different behavioral contexts. The main behavioral contexts of each sound type were significantly associated with the acoustic variable ordination of different sound types. A strong correlation between vocal complexity and sociability was found for different species, suggesting that the communication systems observed in the family mustelidae support the social intelligence hypothesis.

Salton Sea ecosystem monitoring and assessment plan

USGS Publications Warehouse

Case(compiler), H. L.; Boles, Jerry; Delgado, Arturo; Nguyen, Thang; Osugi, Doug; Barnum, Douglas A.; Decker, Drew; Steinberg, Steven; Steinberg, Sheila; Keene, Charles; White, Kristina; Lupo, Tom; Gen, Sheldon; Baerenklau, Ken A.

2013-01-01

The Salton Sea, California’s largest lake, provides essential habitat for several fish and wildlife species and is an important cultural and recreational resource. It has no outlet, and dissolved salts contained in the inflows concentrate in the Salton Sea through evaporation. The salinity of the Salton Sea, which is currently nearly one and a half times the salinity of ocean water, has been increasing as a result of evaporative processes and low freshwater inputs. Further reductions in inflows from water conservation, recycling, and transfers will lower the level of the Salton Sea and accelerate the rate of salinity increases, reduce the suitability of fish and wildlife habitat, and affect air quality by exposing lakebed playa that could generate dust. Legislation enacted in 2003 to implement the Quantification Settlement Agreement (QSA) stated the Legislature’s intent for the State of California to undertake the restoration of the Salton Sea ecosystem. As required by the legislation, the California Resources Agency (now California Natural Resources Agency) produced the Salton Sea Ecosystem Restoration Study and final Programmatic Environmental Impact Report (PEIR; California Resources Agency, 2007) with the stated purpose to “develop a preferred alternative by exploring alternative ways to restore important ecological functions of the Salton Sea that have existed for about 100 years.” A decision regarding a preferred alternative currently resides with the California State Legislature (Legislature), which has yet to take action. As part of efforts to identify an ecosystem restoration program for the Salton Sea, and in anticipation of direction from the Legislature, the California Department of Water Resources (DWR), California Department of Fish and Wildlife (CDFW), U.S. Bureau of Reclamation (Reclamation), and U.S. Geological Survey (USGS) established a team to develop a monitoring and assessment plan (MAP). This plan is the product of that effort. The goal of the MAP is to provide a guide for data collection, analysis, management, and reporting to inform management actions for the Salton Sea ecosystem. Monitoring activities are directed at species and habitats that could be affected by or drive future restoration activities. The MAP is not intended to be a prescriptive document. Rather, it is envisioned to be a flexible, program-level guide that articulates high-level goals and objectives, and establishes broad sideboards within which future project-level investigations and studies will be evaluated and authorized. As such, the MAP, by design, does not, for example, include detailed protocols describing how investigations will be implemented. It is anticipated that detailed study proposals will be prepared as part of an implementation plan that will include such things as specific sampling objectives, sampling schemes, and statistical and spatial limits.

Cryptococcus albidus infection in a California sea lion (Zalophus californianus).

PubMed

Mcleland, Shannon; Duncan, Colleen; Spraker, Terry; Wheeler, Elizabeth; Lockhart, Shawn R; Gulland, Frances

2012-10-01

Sporadic cases of cryptococcosis have been reported in marine mammals, typically due to Cryptococcus neoformans and, more recently, to Cryptococcus gattii in cetaceans. Cryptococcus albidus, a ubiquitous fungal species not typically considered to be pathogenic, was recovered from a juvenile California sea lion (Zalophus californianus) rescued near San Francisco Bay, California. Yeast morphologically consistent with a Cryptococcus sp. was identified histologically in a lymph node and C. albidus was identified by an rDNA sequence from the lung. Infection with C. albidus was thought to have contributed to mortality in this sea lion, along with concurrent bacterial pneumonia. Cryptococcus albidus should be considered as a potential pathogen with a role in marine mammal morbidity and mortality.

Metastrongyloid nematode (Otostrongylus circumlitus) infection in a stranded California sea lion (Zalophus californianus)--a new host-parasite association.

PubMed

Kelly, Terra R; Greig, Denise; Colegrove, Kathleen M; Lowenstine, Linda J; Dailey, Murray; Gulland, Frances M; Haulena, Martin

2005-07-01

A stranded yearling male California sea lion was admitted to a rehabilitation center June 2003. On presentation, the sea lion was emaciated and had diarrhea and neutrophilia. Two weeks later, the animal became anorexic, blood and mucus were observed around the oral cavity, and corneal opacity was noted in the right eye. Hematology results at that time included leukocytosis consisting of neutrophilia with a left shift, anemia, and thrombocytopenia. Despite supportive care, the sea lion died. On post mortem examination, there were multiple areas of hemorrhage scattered throughout all lung lobes, and pulmonary blood vessels were occluded by fibrin thrombi. Nematodes identified as immature forms of Otostrongylus circumlitus were found in the right ventricle and pulmonary arteries. Histologic findings in the lungs included severe suppurative and necrotizing arteritis with vascular thrombosis, interstitial pneumonia, and large areas of pulmonary hemorrhage. This report of O. circumlitus infection in a California sea lion (Zalophus californianus) might indicate a potentially new host-parasite association.

A Robotic Platform to Study the Foreflipper of the California Sea Lion.

PubMed

Kulkarni, Aditya A; Patel, Rahi K; Friedman, Chen; Leftwich, Megan C

2017-01-10

The California sea lion (Zalophus californianus), is an agile and powerful swimmer. Unlike many successful swimmers (dolphins, tuna), they generate most of their thrust with their large foreflippers. This protocol describes a robotic platform designed to study the hydrodynamic performance of the swimming California sea lion (Zalophus californianus). The robot is a model of the animal's foreflipper that is actuated by motors to replicate the motion of its propulsive stroke (the 'clap'). The kinematics of the sea lion's propulsive stroke are extracted from video data of unmarked, non-research sea lions at the Smithsonian Zoological Park (SNZ). Those data form the basis of the actuation motion of the robotic flipper presented here. The geometry of the robotic flipper is based a on high-resolution laser scan of a foreflipper of an adult female sea lion, scaled to about 60% of the full-scale flipper. The articulated model has three joints, mimicking the elbow, wrist and knuckle joint of the sea lion foreflipper. The robotic platform matches dynamics properties-Reynolds number and tip speed-of the animal when accelerating from rest. The robotic flipper can be used to determine the performance (forces and torques) and resulting flowfields.

California Ocean Research: A Sea Grant Sampler. Sea Grant Publication No. 65, Spring 1978.

ERIC Educational Resources Information Center

Brownlee, Shannon; And Others

This booklet, written, illustrated, edited, and produced by four interns from the science writing program of the University of California, Santa Cruz, explains seven ocean research projects. The projects are in the fields of: energy, marine education, fishery management, coastal zone management, marine advisory services, aquaculture, and new…

Dissecting the Influences of Climate and Demography on the Dynamics of Leptospirosis in California Sea Lions

USDA-ARS?s Scientific Manuscript database

Leptospirosis is a zoonotic infection of global importance, yet its population dynamics remain poorly understood. We present the first empirically-motivated study of the dynamics of leptospirosis, drawing on a unique 24-year time series of disease in California sea lions (CSLs). Since the early 19...

Earthshots: Satellite images of environmental change – Imperial Valley, California, USA

USGS Publications Warehouse

,

2013-01-01

At the bottom of the sink lies the Salton Sea, the largest lake in California. It lacks an outlet to the ocean and lies 70 m below sea level. About 85% of the sea’s inflows come from agricultural runoff, and its waters are 37% saltier than the Pacific Ocean.

Penetration of the small intestine of a California sea lion (Zalophus californianus) pup by adult hookworms (Uncinaria spp).

PubMed

Spraker, T R; Lyons, E T; DeLong, R L; Zink, R R

2004-03-01

During a study on the mortality of California sea lion (Zalophus californianus) pups born on San Miguel Island, California in 2002, two adult female hookworms (Uncinaria spp) were found penetrating the serosal surface of the intestinal wall and protruding into the peritoneal cavity of one pup. Documentation and a description of this unexpected finding and associated lesions are presented here. Also, adult hookworms were found in the peritoneal fluid of two other dead Z. californianus pups.

Tissue heavy metal concentrations of stranded California sea lions (Zalophus californianus) in Southern California.

PubMed

Harper, Erin R; St Leger, Judy A; Westberg, Jody A; Mazzaro, Lisa; Schmitt, Todd; Reidarson, Tom H; Tucker, Melinda; Cross, Dee H; Puschner, Birgit

2007-06-01

Concentrations of nine heavy metals (As, Cd, Cu, Fe, Hg, Pb, Mn, Mo and Zn) were determined in the hepatic and renal tissues of 80 stranded California sea lions (Zalophus californianus). Significant age-dependant increases were observed in liver and kidney concentrations of cadmium and mercury, and renal zinc concentrations. Hepatic iron concentrations were significantly higher in females than males. Animals with suspected domoic acid associated pathological findings had significantly higher concentrations of liver and kidney cadmium; and significantly higher liver mercury concentrations when compared to animals classified with infectious disease or traumatic mortality. Significantly higher hepatic burdens of molybdenum and zinc were found in animals that died from infectious diseases. This is the largest study of tissue heavy metal concentrations in California sea lions to date. These data demonstrate how passive monitoring of stranded animals can provide insight into environmental impacts on marine mammals.

Organochlorine pesticides and polychlorinated biphenyls in California sea lions (Zalophus californianus californianus) from the Gulf of California, México.

PubMed

Niño-Torres, Carlos Alberto; Gardner, Susan C; Zenteno-Savín, Tania; Ylitalo, Gina M

2009-02-01

We report concentrations of several classes of organochlorines (OCs) in the blubber of California sea lions (Zalophus californianus) from the Gulf of California. Summed OC levels measured in 34 wild-ranging animals were, in general, lower than those previously reported in sea lions from the eastern Pacific. The rank order of OCs was SigmaDDTs (mean=3400 ng g(-1 ) lipid weight [lw]) > SigmaPCBs (1400 ng g(-1 ) lw) > SigmaHCHs (50 ng g(-1 ) lw) >or= SigmaCHLORs (46 ng g(-1 ) lw). The most abundant OC measured was the DDT metabolite, p,p'-DDE. No significant differences in OC profiles were found between genders or rookeries. Although the mean concentrations of OCs measured in adult males and females were similar, only adult females had significantly higher (p<0.05) mean blubber concentrations of summation SigmaDDTs and summation SigmaHCHs than pups.

Size, growth, and density data for shallow-water sea urchins from Mexico to the Aleutian Islands, Alaska, 1956-2016.

PubMed

Ebert, Thomas A; Barr, Louis M; Bodkin, James L; Burcham, Dirk; Bureau, Dominique; Carson, Henry S; L Caruso, Nancy; Caselle, Jennifer E; Claisse, Jeremy T; Clemente, Sabrina; Davis, Kathryn; Detwiler, Paul M; Dixon, John D; Duggins, David O; Engle, John M; Estes, James A; Groth, Scott D; Grupe, Benjamin M; Halmay, Peter; Hebert, Kyle P; Hernández, José C; Jurgens, Laura J; Kalvass, Peter E; Kenner, Michael C; Konar, Brenda; Kushner, David J; Lee, Lynn C; Leighton, David L; Montaño-Moctezuma, Gabriela; Eric Munk, J; Olguin, Irma; Palleiro, Julio S; Parker, David O; Pearse, John S; Pondella, Daniel J; Rogers-Bennett, Laura; Schroeter, Stephen C; Shelton, Andrew Olaf; Sonnenholzner, Jorge; Taniguchi, Ian K; VanBlaricom, Glenn R; Watson, Jane C; Weitzman, Benjamin P; Williams, Jonathan P; Yakimishyn, Jennifer; Zhang, Zane

2018-03-01

Size, growth, and density have been studied for North American Pacific coast sea urchins Strongylocentrotus purpuratus, S. droebachiensis, S. polyacanthus, Mesocentrotus (Strongylocentrotus) franciscanus, Lytechinus pictus, Centrostephanus coronatus, and Arbacia stellata by various workers at diverse sites and for varying lengths of time from 1956 to present. Numerous peer-reviewed publications have used some of these data but some data have appeared only in graduate theses or the gray literature. There also are data that have never appeared outside original data sheets. Motivation for studies has included fisheries management and environmental monitoring of sewer and power plant outfalls as well as changes associated with disease epidemics. Studies also have focused on kelp restoration, community effects of sea otters, basic sea urchin biology, and monitoring. The data sets presented here are a historical record of size, density, and growth for a common group of marine invertebrates in intertidal and nearshore environments that can be used to test hypotheses concerning future changes associated with fisheries practices, shifts of predator distributions, climate and ecosystem changes, and ocean acidification along the Pacific Coast of North America and islands of the north Pacific. No copyright restrictions apply. Please credit this paper when using the data. © 2017 by the Ecological Society of America.

Distribution of Bottom Trawling Effort in the Yellow Sea and East China Sea

PubMed Central

Zhang, Shengmao; Jin, Shaofei; Zhang, Heng; Fan, Wei; Tang, Fenghua; Yang, Shenglong

2016-01-01

Bottom trawling is one of the most efficient fishing activities, but serious and persistent ecological issues have been observed by fishers, scientists and fishery managers. Although China has applied the Beidou fishing vessel position monitoring system (VMS) to manage trawlers since 2006, little is known regarding the impacts of trawling on the sea bottom environments. In this study, continuous VMS data of the 1403 single-rig otter trawlers registered in the Xiangshan Port, 3.9% of the total trawlers in China, were used to map the trawling effort in 2013. We used the accumulated distance (AD), accumulated power distance (APD), and trawling intensity as indexes to express the trawling efforts in the Yellow Sea (YS) and East China Sea (ECS). Our results show that all three indexes had similar patterns in the YS and ECS, and indicated a higher fishing effort of fishing grounds that were near the port. On average, the seabed was trawled 0.73 times in 2013 over the entire fishing region, and 51.38% of the total fishing grounds were with no fishing activities. Because of VMS data from only a small proportion of Chinese trawlers was calculated fishing intensity, more VMS data is required to illustrate the overall trawling effort in China seas. Our results enable fishery managers to identify the distribution of bottom trawling activities in the YS and ECS, and hence to make effective fishery policy. PMID:27855215

Territorial choruses of giant otter groups (Pteronura brasiliensis) encode information on group identity.

PubMed

Mumm, Christina A S; Knörnschild, Mirjam

2017-01-01

Group living animals often engage in corporate territorial defence. Territorial group vocalizations can provide information about group identity, size and composition. Neighbouring groups may use this information to avoid unfavourable direct conflicts. Giant otters are highly social and territorial animals with an elaborate vocal repertoire. They produce long-range screams when they are alert or excited, i.e. in an alarm, isolation or begging context. Long-range screams are not only produced by one individual at a time ('single screams') but also by multiple group members simultaneously, resulting in a highly conspicuous 'group chorus'. Wild giant otters regularly produce group choruses during interactions with predators, when they detect intruders in their territory or before group reunions after separation. Since single screams and especially group choruses probably contribute to the groups' corporate territorial defence, we hypothesized that group identity is encoded in single screams and group choruses. We analysed vocalizations from five wild and three captive giant otter groups and found statistical evidence for a group signature in group choruses. Results for single screams were less conclusive, which might have been caused by the comparatively lower sample size. We suggest that giant otters may gain information on group identity by listening to group choruses. Group identity likely constitutes important social information for giant otters since territory boundaries of neighbouring groups can overlap and direct inter-group conflicts are severe. Therefore, group chorusing may contribute to the mutual avoidance of members from different groups.

The environmental impacts of three different queen scallop (Aequipecten opercularis) fishing gears.

PubMed

Hinz, Hilmar; Murray, Lee G; Malcolm, Fraser R; Kaiser, Michel J

2012-02-01

The negative impact of demersal fishing gears on the marine environment may be mitigated by utilizing less damaging fishing gears. Within this context three queen scallop fishing gears were tested for their catch efficiencies and their environmental impact on benthos: a traditional 'Newhaven' dredge, a new dredge design with a rubber lip instead of the traditional teeth as its main new design feature and an otter trawl. Both, the new dredge and the otter trawl showed high catches and relatively low by-catches. Catches made with the traditional dredge were lower and contained larger amounts of non-target species. Both dredges primarily caught invertebrate species, while by-catches of the otter trawl were dominated by demersal fish. The impact of these gears on the benthic biota demonstrated that while no effects were detected for the otter trawl both dredges showed similar negative effects. Clear negative effects were evident for the brittlestar Ophiura ophiura while positive trends for the common starfish Asterias rubens and the hermit crab Pagurus bernhardus indicated scavenging effects. Due to its higher catch efficiency the new dredge caused less damage per unit catch compared to the traditional dredge, yet compared to the otter trawl it appears less environmentally friendly. However, the new dredge may be an alternative to the otter trawls for fisheries where the by-catch of demersal fish has been identified as a significant problem. Copyright © 2011 Elsevier Ltd. All rights reserved.

Determination of sound types and source levels of airborne vocalizations by California sea lions, Zalophus californianus, in rehabilitation at the Marine Mammal Center in Sausalito, California

NASA Astrophysics Data System (ADS)

Schwalm, Afton Leigh

California sea lions (Zalophus californianus) are a highly popular and easily recognized marine mammal in zoos, aquariums, circuses, and often seen by ocean visitors. They are highly vocal and gregarious on land. Surprisingly, little research has been performed on the vocalization types, source levels, acoustic properties, and functions of airborne sounds used by California sea lions. This research on airborne vocalizations of California sea lions will advance the understanding of this aspect of California sea lions communication, as well as examine the relationship between health condition and acoustic behavior. Using a PhillipsRTM digital recorder with attached microphone and a calibrated RadioShackRTM sound pressure level meter, acoustical data were recorded opportunistically on California sea lions during rehabilitation at The Marine Mammal Center in Sausalito, CA. Vocalizations were analyzed using frequency, time, and amplitude variables with Raven Pro: Interactive Sound Analysis Software Version 1.4 (The Cornell Lab of Ornithology, Ithaca, NY). Five frequency, three time, and four amplitude variables were analyzed for each vocalization. Differences in frequency, time, and amplitude variables were not significant by sex. The older California sea lion group produced vocalizations that were significantly lower in four frequency variables, significantly longer in two time variables, significantly higher in calibrated maximum and minimum amplitude variables, and significantly lower in frequency at maximum and minimum amplitude compared with pups. Six call types were identified: bark, goat, growl/grumble, bark/grumble, bark/growl, and grumble/moan. The growl/grumble call was higher in dominant beginning, ending, and minimum frequency, as well as in the frequency at maximum amplitude compared with the bark, goat, bark/grumble calls in the first versus last vocalization sample. The goat call was significantly higher in first harmonic interval than any other call type in the all vocalizations sample. The "fate" of a sea lion was categorized as: released, placed at another facility, remained at TMMC, euthanized, or died. To determine if acoustic features could be used to assess the recovery of a pup, the acoustic features of a pup's first recorded vocalization were compared with the frequency, time, and amplitude of the last vocalization recorded (i.e., before it was released or placed at another facility). In addition, all first vocalizations were pooled and all last vocalizations were pooled for acoustic analysis, regardless of their fate. Released pups had shorter duration calls, a greater first harmonic interval, and a higher dominant maximum frequency than either pups that died or pups remaining at TMMC. Released pups had a higher frequency at maximum and minimum amplitude compared to dead and remaining pups. Pups that died had significantly lower dominant ending frequency and a lower dominant minimum frequency than released or remaining pups. These results were supported by other studies on different species of otariids, phocids, and cetaceans. The preliminary analyses presented in this thesis holds promise that with additional data acoustic features of California sea lion airborne vocalizations could indicate sex, age, and possibly health condition or the potential for release.

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

PubMed

Williams, Perry J; Hooten, Mevin B; Womble, Jamie N; Esslinger, George G; Bower, Michael R; Hefley, Trevor J

2017-02-01

Ecological invasions and colonizations occur dynamically through space and time. Estimating the distribution and abundance of colonizing species is critical for efficient management or conservation. We describe a statistical framework for simultaneously estimating spatiotemporal occupancy and abundance dynamics of a colonizing species. Our method accounts for several issues that are common when modeling spatiotemporal ecological data including multiple levels of detection probability, multiple data sources, and computational limitations that occur when making fine-scale inference over a large spatiotemporal domain. We apply the model to estimate the colonization dynamics of sea otters (Enhydra lutris) in Glacier Bay, in southeastern Alaska. © 2016 by the Ecological Society of America.

Cyclical changes in seroprevalence of leptospirosis in California sea lions: endemic and epidemic disease in one host species?

PubMed Central

Lloyd-Smith, James O; Greig, Denise J; Hietala, Sharon; Ghneim, George S; Palmer, Lauren; St Leger, Judy; Grenfell, Bryan T; Gulland, Frances MD

2007-01-01

Background Leptospirosis is a zoonotic disease infecting a broad range of mammalian hosts, and is re-emerging globally. California sea lions (Zalophus californianus) have experienced recurrent outbreaks of leptospirosis since 1970, but it is unknown whether the pathogen persists in the sea lion population or is introduced repeatedly from external reservoirs. Methods We analyzed serum samples collected over an 11-year period from 1344 California sea lions that stranded alive on the California coast, using the microscopic agglutination test (MAT) for antibodies to Leptospira interrogans serovar Pomona. We evaluated seroprevalence among yearlings as a measure of incidence in the population, and characterized antibody persistence times based on temporal changes in the distribution of titer scores. We conducted multinomial logistic regression to determine individual risk factors for seropositivity with high and low titers. Results The serosurvey revealed cyclical patterns in seroprevalence to L. interrogans serovar Pomona, with 4–5 year periodicity and peak seroprevalence above 50%. Seroprevalence in yearling sea lions was an accurate index of exposure among all age classses, and indicated on-going exposure to leptospires in non-outbreak years. Analysis of titer decay rates showed that some individuals probably maintain high titers for more than a year following exposure. Conclusion This study presents results of an unprecedented long-term serosurveillance program in marine mammals. Our results suggest that leptospirosis is endemic in California sea lions, but also causes periodic epidemics of acute disease. The findings call into question the classical dichotomy between maintenance hosts of leptospirosis, which experience chronic but largely asymptomatic infections, and accidental hosts, which suffer acute illness or death as a result of disease spillover from reservoir species. PMID:17986335

Molecular and morphometric evidence for separate species of Uncinaria (Nematoda: Ancylostomatidae) in California sea lions and northern fur seals: hypothesis testing supplants verification.

PubMed

Nadler, S A; Adams, B J; Lyons, E T; DeLong, R L; Melin, S R

2000-10-01

California sea lions (Zalophus californianus) and northern fur seals (Callorhinus ursinus) are each believed to host distinct hookworm species (Uncinaria spp.). However, a recent morphometric analysis suggested that a single species parasitizes multiple pinniped hosts, and that the observed differences are host-induced. To explore the systematics of these hookworms and test these competing hypotheses, we obtained nucleotide sequences of nuclear ribosomal DNA (D2/D3 28S, D18/D19 28S, and internal transcribed spacer [ITS] regions) from 20 individual hookworms parasitizing California sea lion and northern fur seal pups where their breeding grounds are sympatric. Five individuals from an allopatric population of California sea lions were also sampled for ITS-1 and D18/D19 28S sequences. The 28S D2/D3 sequences showed no diagnostic differences among hookworms sampled from individual sea lions and fur seals, whereas the 28S D18/D19 sequences had one derived (apomorphic) character demarcating hookworms from northern fur seals. ITS sequences were variable for 7 characters, with 4 derived (apomorphic) states in ITS-1 demarcating hookworms from California sea lions. Multivariate analysis of morphometric data also revealed significant differences between nematodes representing these 2 host-associated lineages. These results indicate that these hookworms represent 2 species that are not distributed indiscriminately between these host species, but instead exhibit host fidelity, evolving independently with each respective host species. This evolutionary approach to analyzing sequence data for species delimitation is contrasted with similarity-based methods that have been applied to numerous diagnostic studies of nematode parasites.

Density of river otters (Lontra canadensis) in relation to energy development in the Green River Basin, Wyoming

USGS Publications Warehouse

Godwin, B.L.; Albeke, S.E.; Bergman, H.L.; Walters, Annika W.; Ben-David, M.

2015-01-01

Exploration and extraction of oil and natural gas have increased in recent years and are expected to expand in the future. Reduction in water quality from energy extraction may negatively affect water supply for agriculture and urban use within catchments as well as down river. We used non-invasive genetic techniques and capture–recapture modeling to estimate the abundance and density of North American river otters (Lontra canadensis), a sentinel species of aquatic ecosystems, in Southwestern Wyoming. While densities in two of three river reaches were similar to those reported in other freshwater systems in the western US (1.45–2.39 km per otter), otters appeared to avoid areas near energy development. We found no strong difference in habitat variables, such as overstory cover, at the site or reach level. Also, fish abundance was similar among the three river reaches. Otter activity in our study area could have been affected by elevated levels of disturbance surrounding the industrial gas fields, and by potential surface water contamination as indicated by patterns in water conductivity. Continued monitoring of surface water quality in Southwestern Wyoming with the aid of continuously recording devices and sentinel species is warranted.

32. Otter Lake Dam. View from downstream show how the ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. Otter Lake Dam. View from downstream show how the dam blends into its environment. Looking east-northeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

77 FR 46430 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-03

... PURPA 210(m)(3) filings: Docket Numbers: QM12-5-000. Applicants: Otter Tail Power Company. Description: Application to Terminate Mandatory PURPA Purchase Obligation of Otter Tail Power Company. Filed Date: 7/25/12...

System description: IVY

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCune, W.; Shumsky, O.

2000-02-04

IVY is a verified theorem prover for first-order logic with equality. It is coded in ACL2, and it makes calls to the theorem prover Otter to search for proofs and to the program MACE to search for countermodels. Verifications of Otter and MACE are not practical because they are coded in C. Instead, Otter and MACE give detailed proofs and models that are checked by verified ACL2 programs. In addition, the initial conversion to clause form is done by verified ACL2 code. The verification is done with respect to finite interpretations.

Diagnosis and treatment of Sarcocystis neurona-induced myositis in a free-ranging California sea lion.

PubMed

Carlson-Bremer, Daphne P; Gulland, Frances M D; Johnson, Christine K; Colegrove, Kathleen M; Van Bonn, William G

2012-02-01

An underweight, lethargic adult female California sea lion (Zalophus californianus) became stranded along the California shore and was captured and transported to a rehabilitation hospital for assessment and care. Initial physical assessment revealed the sea lion was lethargic and in poor body condition. Active myositis was diagnosed on the basis of concurrent elevations in activities of alanine aminotransferase and creatine kinase detected during serum biochemical analysis. Infection with Sarcocystis neurona was diagnosed after serologic titers increased 4-fold over a 3-week period. Diagnosis was confirmed on the basis of histopathologic findings, positive results on immunohistochemical staining, and results of quantitative PCR assay on biopsy specimens obtained from the diaphragm and muscles of the dorsal cervical region. Anticoccidial treatment was instituted with ponazuril (10 mg/kg [4.5 mg/lb], PO, q 24 h) and continued for 28 days. Prednisone (0.2 mg/kg [0.09 mg/lb], PO, q 12 h) was administered for 2 days and then every 24 hours for 5 days to treat associated inflammation. At the end of treatment, the sea lion was clinically normal, alanine aminotransferase and creatine kinase values were within reference limits, and antibody titers against S neurona had decreased 6-fold. The sea lion was released approximately 3 months after becoming stranded. S neurona-induced myositis was diagnosed in a free-ranging California sea lion. On the basis of the successful treatment and release of this sea lion, anticoccidial treatment should be considered for marine mammals in which protozoal disease is diagnosed.

The role of domoic acid in abortion and premature parturition of California sea lions (Zalophus californianus) on San Miguel Island, California.

PubMed

Goldstein, Tracey; Zabka, Tanja S; Delong, Robert L; Wheeler, Elizabeth A; Ylitalo, Gina; Bargu, Sibel; Silver, Mary; Leighfield, Tod; Van Dolah, Frances; Langlois, Gregg; Sidor, Inga; Dunn, J Lawrence; Gulland, Frances M D

2009-01-01

Domoic acid is a glutaminergic neurotoxin produced by marine algae such as Pseudo-nitzschia australis. California sea lions (Zalophus californianus) ingest the toxin when foraging on planktivorous fish. Adult females comprise 60% of stranded animals admitted for rehabilitation due to acute domoic acid toxicosis and commonly suffer from reproductive failure, including abortions and premature live births. Domoic acid has been shown to cross the placenta exposing the fetus to the toxin. To determine whether domoic acid was playing a role in reproductive failure in sea lion rookeries, 67 aborted and live-born premature pups were sampled on San Miguel Island in 2005 and 2006 to investigate the causes for reproductive failure. Analyses included domoic acid, contaminant and infectious disease testing, and histologic examination. Pseudo-nitzschia spp. were present both in the environment and in sea lion feces, and domoic acid was detected in the sea lion feces and in 17% of pup samples tested. Histopathologic findings included systemic and localized inflammation and bacterial infections of amniotic origin, placental abruption, and brain edema. The primary lesion in five animals with measurable domoic acid concentrations was brain edema, a common finding and, in some cases, the only lesion observed in aborted premature pups born to domoic acid-intoxicated females in rehabilitation. Blubber organochlorine concentrations were lower than those measured previously in premature sea lion pups collected in the 1970s. While the etiology of abortion and premature parturition was varied in this study, these results suggest that domoic acid contributes to reproductive failure on California sea lion rookeries.

The history of Toxoplasma gondii--the first 100 years.

PubMed

Dubey, Jitender P

2008-01-01

In this paper the history of Toxoplasma gondii and toxoplasmosis is reviewed. This protozoan parasite was first discovered in 1908 and named a year later. Its medical importance remained unknown until 1939 when T. gondii was identified in tissues of a congenitally infected infant, and veterinary importance became known when it was found to cause abortion storms in sheep in 1957. The discovery of a T. gondii specific antibody test, Sabin-Feldman dye test in 1948 led to the recognition that T. gondii is a common parasite of warm-blooded hosts with a worldwide distribution. Its life cycle was not discovered until 1970 when it was found that felids are its definitive host and an environmentally resistant stage (oocyst) is excreted in feces of infected cats. The recent discovery of its common infection in certain marine wildlife (sea otters) indicates contamination of our seas with T. gondii oocysts washed from land. Hygiene remains the best preventive measure because currently there is no vaccine to prevent toxoplasmosis in humans.

First report of a naturally patent infection with Dirofilaria immitis in an otter (Lutra lutra).

PubMed

Penezić, Aleksandra; Moriano, Roberta; Spasić, Marija; Ćirović, Duško

2018-03-01

Dirofilaria immitis causes a severe and life-threatening cardio-pulmonary disease in Europe, Asia, Africa, and the Americas; also, zoonotic infections have been reported. This parasitic vector-borne disease is mostly common in domestic and wild canids and felids. Here, we present a rare finding of this roundworm in the heart of a Eurasian otter (Lutra lutra). Four mature specimens of D. immitis were found in the right ventricle of the heart. Necropsy was performed after the animal was found road-killed in Eastern Serbia, close to the Danube River. Two heartworms were females, one was male and sex for one remained unidentified. Microfilariae were present in the uterus of one of the female heartworms, indicating that otters can act as reservoirs of dirofilariasis in the wild. This is the first report of a patent infection in a free-ranging otter.

Sea-level rise and refuge habitats for tidal marsh species: can artificial islands save the California Ridgway's rail?

USGS Publications Warehouse

Overton, Cory T.; Takekawa, John Y.; Casazza, Michael L.; Bui, Thuy-Vy D.; Holyoak, Marcel; Strong, Donald R.

2014-01-01

Terrestrial species living in intertidal habitats experience refuge limitation during periods of tidal inundation, which may be exacerbated by seasonal variation in vegetation structure, tidal cycles, and land-use change. Sea-level rise projections indicate the severity of refuge limitation may increase. Artificial habitats that provide escape cover during tidal inundation have been proposed as a temporary solution to alleviate these limitations. We tested for evidence of refuge habitat limitation in a population of endangered California Ridgway's rail (Rallus obsoletus obsoletus; hereafter California rail) through use of artificial floating island habitats provided during two winters. Previous studies demonstrated that California rail mortality was especially high during the winter and periods of increased tidal inundation, suggesting that tidal refuge habitat is critical to survival. In our study, California rail regularly used artificial islands during higher tides and daylight hours. When tide levels inundated the marsh plain, use of artificial islands was at least 300 times more frequent than would be expected if California rails used artificial habitats proportional to their availability (0.016%). Probability of use varied among islands, and low levels of use were observed at night. These patterns may result from anti-predator behaviors and heterogeneity in either rail density or availability of natural refuges. Endemic saltmarsh species are increasingly at risk from habitat change resulting from sea-level rise and development of adjacent uplands. Escape cover during tidal inundation may need to be supplemented if species are to survive. Artificial habitats may provide effective short-term mitigation for habitat change and sea-level rise in tidal marsh environments, particularly for conservation-reliant species such as California rails.

PHARMACOKINETICS OF SINGLE-DOSE ORALLY ADMINISTERED CIPROFLOXACIN IN CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS).

PubMed

Barbosa, Lorraine; Johnson, Shawn P; Papich, Mark G; Gulland, Frances

2015-06-01

Ciprofloxacin is commonly selected for clinical use due to its broad-spectrum efficacy and is a frequently administered antibiotic at The Marine Mammal Center, a marine mammal rehabilitation facility. Ciprofloxacin is used for treatment of California sea lions ( Zalophus californianus ) suffering from a variety of bacterial infections at doses extrapolated from other mammalian species. However, as oral absorption is variable both within and across species, a more accurate determination of appropriate dosage is needed to ensure effective treatment and avoid emergence of drug-resistant bacterial strains. A pharmacokinetic study was performed to assess plasma concentrations of ciprofloxacin in California sea lions after a single oral dose. Twenty healthy California sea lions received a single 10-mg/kg oral dose of ciprofloxacin administered in a herring fish. Blood was then collected at two of the following times from each individual: 0.5, 0.75, 1, 2, 4, 8, 10, 12, 18, and 24 hr postingestion. Plasma ciprofloxacin concentration was assessed via high-performance liquid chromatography. A population pharmacokinetics model demonstrated that an oral ciprofloxacin dose of 10 mg/kg achieved an area under the concentration vs. time curve of 6.01 μg hr/ml. Absorption was rapid, with ciprofloxacin detectable in plasma 0.54 hr after drug administration; absorption half-life was 0.09 hr. A maximum plasma concentration of 1.21 μg/ml was observed at 1.01 hr, with an elimination half-life of 3.09 hr. Ciprofloxacin administered orally at 10 mg/kg produced therapeutic antibacterial exposure for only some of the most susceptible bacterial organisms commonly isolated from California sea lions.

Influence of El Niño–Southern Oscillation (ENSO) events on the evolution of central California's shoreline

USGS Publications Warehouse

Storlazzi, Curt D.; Griggs, Gary B.

2000-01-01

Significant sea-cliff erosion and storm damage occurred along the central coast of California during the 1982–1983 and 1997–1998 El Niño winters. This generated interest among scientists and land-use planners in how historic El Niño–Southern Oscillation (ENSO) winters have affected the coastal climate of central California. A relative ENSO intensity index based on oceanographic and meteorologic data defines the timing and magnitude of ENSO events over the past century. The index suggests that five higher intensity (relative values 4–6) and 17 lower intensity (relative values 1–3) ENSO events took place between 1910 and 1995. The ENSO intensity index correlates with fluctuations in the time series of cyclone activity, precipitation, detrended sea level, wave height, sea-surface temperature, and sea-level barometric pressure. Wave height, sea level, and precipitation, which are the primary external forcing parameters in sea-cliff erosion, increase nonlinearly with increasing relative ENSO event intensity. The number of storms that caused coastal erosion or storm damage and the historic occurrence of large-scale sea-cliff erosion along the central coast also increase nonlinearly with increasing relative event intensity. These correlations and the frequency distribution of relative ENSO event intensities indicate that moderate- to high-intensity ENSO events cause the most sea-cliff erosion and shoreline recession over the course of a century.

Use of laser rhinoscopy to treat a nasal obstruction in a captive California sea lion (Zalophus californianus).

PubMed

Sherrill, Johanna; Peavy, George M; Kopit, Mark J; Garner, Michael M; Gardiner, Chris H; Adams, Lance M

2004-06-01

Laser rhinoscopy was used to treat a nasal obstruction in a captive California sea lion (Zalophus californianus). The rehabilitated, adult, female sea lion developed mucopurulent, intermittent, bilateral nasal discharge and functional nasal obstruction 20 mo after acquisition by the Aquarium of the Pacific in Long Beach, California. A 3-mm-thick soft tissue structure spanning the region between the soft and hard palates, a deviated nasal septum, and several nasopharyngeal polyps were identified. Biopsies and cultures of the obstructive web showed ulcerative granulation tissue with suppurative inflammation, bacterial infection, and a partial section of an arthropod larva (not speciated). Laser rhinoscopy was performed to relieve the caudal nasopharyngeal obstruction and ablate the polyps. The sea lion appeared to breathe through the nares with lessened nasal discharge for a period of 6 wk after laser therapy, but within 8 wk the mucopurulent nasal discharge returned, the obstruction had reformed, and the sea lion was euthanized. Postmortem examination confirmed antemortem diagnoses of caudal nasopharyngeal obstruction secondary to inflammatory tissue; however, no additional sections of arthropod parasites were located microscopically.

Views of the Sea Floor in Northern Monterey Bay, California

USGS Publications Warehouse

Storlazzi, Curt D.; Golden, Nadine E.; Finlayson, David P.

2008-01-01

A sonar survey that produced unprecedented high-resolution images of the sea floor in northern Monterey Bay was conducted in 2005 and 2006. The survey, performed over 14 days by the U.S. Geological Survey (USGS), consisted of 172 tracklines and over 300 million soundings and covered an area of 12.2 km2 (4.7 mi2). The goals of this survey were to collect high-resolution bathymetry (depth to the sea floor) and acoustic backscatter data (amount of sound energy bounced back from the sea floor, which provides information on sea-floor hardness and texture) from the inner continental shelf. These data will provide a baseline for future change analyses, geologic mapping, sediment- and contaminant-transport studies, benthic-habitat delineation, and numerical modeling efforts. The survey shows that the inner shelf in this area is extremely varied in nature, encompassing flat sandy areas, faults, boulder fields, and complex bedrock ridges that support rich marine ecosystems. Furthermore, many of these complex bedrock ridges form the ?reefs? that result in a number of California?s classic surf breaks.

Chapter 35: Productivity of marbled murrelets in California from observations of young at sea

Treesearch

C. John Ralph; Linda L. Long

1995-01-01

We designed and tested an intensive survey method in 1993 to identify juvenile Marbled Murrelets (Brachyramphus marmoratus) at sea. From this, we used the percent of juveniles seen in the sample as an index of productivity of murrelets along the California coast. We found 2.2 percent of the population sampled were juveniles, similar to our estimates...

Common cancer in a wild animal: the California sea lion (Zalophus californianus) as an emerging model for carcinogenesis

PubMed Central

Browning, Helen M.; Gulland, Frances M. D.; Hammond, John A.; Colegrove, Kathleen M.; Hall, Ailsa J.

2015-01-01

Naturally occurring cancers in non-laboratory species have great potential in helping to decipher the often complex causes of neoplasia. Wild animal models could add substantially to our understanding of carcinogenesis, particularly of genetic and environmental interactions, but they are currently underutilized. Studying neoplasia in wild animals is difficult and especially challenging in marine mammals owing to their inaccessibility, lack of exposure history, and ethical, logistical and legal limits on experimentation. Despite this, California sea lions (Zalophus californianus) offer an opportunity to investigate risk factors for neoplasia development that have implications for terrestrial mammals and humans who share much of their environment and diet. A relatively accessible California sea lion population on the west coast of the USA has a high prevalence of urogenital carcinoma and is regularly sampled during veterinary care in wildlife rehabilitation centres. Collaborative studies have revealed that genotype, persistent organic pollutants and a herpesvirus are all associated with this cancer. This paper reviews research to date on the epidemiology and pathogenesis of urogenital carcinoma in this species, and presents the California sea lion as an important and currently underexploited wild animal model of carcinogenesis. PMID:26056370

Increased Internal Atmospheric Variability Contributed to the Persistence of the California Drought Through the 2015/16 El Niño

NASA Astrophysics Data System (ADS)

Zaiss, J.; Stott, L. D.; Buenning, N. H.

2017-12-01

The 2015/16 El Niño was one of the strongest on record and was expected to bring relief to the prolonged drought that had affected California for the previous four years. Virtually all seasonal forecast models predicted a wet winter over California, similar to the 1997/98 El Niño winter season. However, as the El Niño event came and went, the drought persisted through 2015/16. We are investigating why the 2015/16 El Niño winter was anomalous dry by conducting ensemble simulations using the atmospheric Global Spectral Model (GSM) forced with observed sea surface temperatures and sea ice concentration. Our results indicate increased variance in precipitation amounts compared to the 1997/98 El Niño, possibly suggesting an increase in atmospheric internal variability. Recent work has shown a possible role of declining Arctic sea ice in mid-latitude weather extremes through variations of the jet stream that could account for the increased precipitation variance. When Arctic sea ice concentrations are low, the jet stream tends to be wavier, slowing meanders that propagate storm systems towards the southwestern US. To investigate the role that sea ice decline played in prolonging the California drought and the observed change in precipitation variance, statistical analyses of metrological data together with ensemble simulations with GSM are used to evaluate differences between the 1997/98 and 2015/2016 El Niño events. We force GSM with 1997/98 SST anomalies but use the 2015/16 sea ice concentration. By doing so we quantify the effect of decreased sea ice concentration on the 2015/16 El Niño event wet season. These results not only elucidate how declining sea ice affected mid-latitude weather systems during the 2015/16 El Niño winter, they also contribute to the ongoing discussion about how declining sea ice may influence weather events and their predictability in the 21st century.

32. Historic American Buildings Survey From California State Library Sacramento, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. Historic American Buildings Survey From California State Library Sacramento, California Original: Re-photo: February 1940 DETAIL OF ENTRANCE (East Elevation) - Mission San Carlos Borromeo, Rio Road & Lausen Drive, Carmel-by-the-Sea, Monterey County, CA

6. Historic American Buildings Survey From California State Library Sacramento, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Historic American Buildings Survey From California State Library Sacramento, California Original: Ante 1860 Re-photo: February 1940 VIEW FROM SOUTHEAST - Mission San Carlos Borromeo, Rio Road & Lausen Drive, Carmel-by-the-Sea, Monterey County, CA

Final Project Report - ARM CLASIC CIRPAS Twin Otter Aerosol

DOE Office of Scientific and Technical Information (OSTI.GOV)

John A. Ogren

2010-04-05

The NOAA/ESRL/GMD aerosol group made three types of contributions related to airborne measurements of aerosol light scattering and absorption for the Cloud and Land Surface Interaction Campaign (CLASIC) in June 2007 on the Twin Otter research airplane operated by the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS). GMD scientists served as the instrument mentor for the integrating nephelometer and particle soot absorption photometer (PSAP) on the Twin Otter during CLASIC, and were responsible for (1) instrument checks/comparisons; (2) instrument trouble shooting/repair; and (3) data quality control (QC) and submittal to the archive.

Dietary specifications reflect the feeding behaviour of the European otter (Lutra lutra) in "Strandzha" Natural Park (Bulgaria)

NASA Astrophysics Data System (ADS)

Natchev, Nikolay; Petkov, Zahari; Dashev, Georgi; Atanasova, Ivanka; Chipev, Nesho

2015-12-01

Within the scope of the present study a field survey in the area of "Strandzha" Natural Park in south-east Bulgaria was carried out. The main goal of the investigation was to gain more detailed information on the diet of the European otters (Lutra lutra) that inhabit the park. As indicators for the presence of the mustelids a set of standard procedures, such as footprints tracking and inspecting the terrain for otter spraints were used. A total of 204 excrements were found, measured, documented and then disintegrated in water. The food rests in the faeces were investigated and the diet of the local population was documented. On the base of the results we separated the excrements into six groups and analysed the relations between the contents of the spraints and the characteristics of the habitat where they were found. We discovered a clear tendency toward piscivory in the middle and down streams of the studied rivers in the Natural Park. In the upper streams, otters relied almost exclusively on invertebrates like bivalves and crayfish as food source. The fact, that even suboptimal habitats, which offered invariable menu, were exploited by the otters is an indication for the stability of the local population.

Cryptosporidium and Giardia in marine-foraging river otters (Lontra canadensis) from the Puget Sound Georgia Basin ecosystem.

PubMed

Gaydos, J K; Miller, W A; Gilardi, K V K; Melli, A; Schwantje, H; Engelstoft, C; Fritz, H; Conrad, P A

2007-02-01

Species of Cryptosporidium and Giardia can infect humans and wildlife and have the potential to be transmitted between these 2 groups; yet, very little is known about these protozoans in marine wildlife. Feces of river otters (Lontra canadensis), a common marine wildlife species in the Puget Sound Georgia Basin, were examined for species of Cryptosporidium and Giardia to determine their role in the epidemiology of these pathogens. Using ZnSO4 flotation and immunomagnetic separation, followed by direct immunofluorescent antibody detection (IMS/DFA), we identified Cryptosporidium sp. oocysts in 9 fecal samples from 6 locations and Giardia sp. cysts in 11 fecal samples from 7 locations. The putative risk factors of proximate human population and degree of anthropogenic shoreline modification were not associated with the detection of Cryptosporidium or Giardia spp. in river otter feces. Amplification of DNA from the IMS/DFA slide scrapings was successful for 1 sample containing > 500 Cryptosporidium sp. oocysts. Sequences from the Cryptosporidium 18S rRNA and the COWP loci were most similar to the ferret Cryptosporidium sp. genotype. River otters could serve as reservoirs for Cryptosporidium and Giardia species in marine ecosystems. More work is needed to better understand the zoonotic potential of the genotypes they carry as well as their implications for river otter health.

Eurasian otters, Lutra lutra, have a dominant mtDNA haplotype from the Iberian Peninsula to Scandinavia.

PubMed

Ferrando, Ainhoa; Ponsà, Montserrat; Marmi, Josep; Domingo-Roura, Xavier

2004-01-01

The Eurasian otter, Lutra lutra, has a Palaearctic distribution and has suffered a severe decline throughout Europe during the last century. Previous studies in this and other mustelids have shown reduced levels of variability in mitochondrial DNA, although otter phylogeographic studies were restricted to central-western Europe. In this work we have sequenced 361 bp of the mtDNA control region in 73 individuals from eight countries and added our results to eight sequences available from GenBank and the literature. The range of distribution has been expanded in relation to previous works north towards Scandinavia, east to Russia and Belarus, and south to the Iberian Peninsula. We found a single dominant haplotype in 91.78% of the samples, and six more haplotypes deviating a maximum of two mutations from the dominant haplotype restricted to a single country. Variability was extremely low in western Europe but higher in eastern countries. This, together with the lack of phylogeographical structuring, supports the postglacial recolonization of Europe from a single refugium. The Eurasian otter mtDNA control region has a 220-bp variable minisatellite in Domain III that we sequenced in 29 otters. We found a total of 19 minisatellite haplotypes, but they showed no phylogenetic information.

Sea level response to ENSO along the central California coast: How the 1997-1998 event compares with the historic record

USGS Publications Warehouse

Ryan, H.F.; Noble, M.

2002-01-01

Long-term monthly sea level and sea surface temperature (SST) anomalies from central California show that during winter months, positive anomalies are associated with El Nin??o events and the negative ones with La Nin??a events. There is no significant impact on monthly mean anomalies associated with Pacific decadal oscillations, although there is a tendency for more extreme events and greater variance during positive decadal oscillations. The very strong 1997-1998 El Nin??o was analyzed with respect to the long-term historic record to assess the forcing mechanisms for sea level and SST. Beginning in the spring of 1997, we observed several long-period (> 30days) fluctuations in daily sea level with amplitudes of over 10 cm at San Francisco, California. Fluctuations of poleward long-period alongshore wind stress anomalies (AWSA) are coherent with the sea level anomalies. However, the wind stress cannot entirely account for the observed sea level signals. The sea level fluctuations are also correlated with sea level fluctuations observed further south at Los Angeles and Tumaco, Columbia, which showed a poleward phase propagation of the sea level signal. We suggest that the sea level fluctuations were, to a greater degree, forced by the passage of remotely generated and coastally trapped waves that were generated along the equator and propagated to the north along the west coast of North America. However, both local and remote AWSA can significantly modulate the sea level signals. The arrival of coastally trapped waves began in the spring of 1997, which is earlier than previous strong El Nin??o events such as the 1982-1983 event. Published by Elsevier Science Ltd.

Real-time simulation program for De Havilland (Canada) "Buffalo" and "Twin Otter" STOL transports

DOT National Transportation Integrated Search

1971-06-25

Simulation models of two representative STOL aircraft - the DeHavilland (Canada) "Buffalo" and "Twin Otter" transports - have been generated. The aircraft are described by means of nonlinear equations that will accommodate gross changes in angle of a...

33 CFR 165.T11-304 - Safety zone; Sea World Summer Nights Fireworks; Mission Bay, San Diego, California.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety zone; Sea World Summer Nights Fireworks; Mission Bay, San Diego, California. 165.T11-304 Section 165.T11-304 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREA...

Modeling Gas Dynamics in California Sea Lions

DTIC Science & Technology

2015-09-30

W. and Fahlman, A. (2009). Could beaked whales get the bends?. Effect of diving behaviour and physiology on modelled gas exchange for three species...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Modeling Gas Dynamics in California Sea Lions Andreas...to update a current gas dynamics model with recently acquired data for respiratory compliance (P-V), and body compartment size estimates in

33. Historic American Buildings Survey From California State Library Sacramento, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. Historic American Buildings Survey From California State Library Sacramento, California Original: 1860's Re-photo: February 1940 INTERIOR OF CHURCH BEFORE RESTORATION - Mission San Carlos Borromeo, Rio Road & Lausen Drive, Carmel-by-the-Sea, Monterey County, CA

9. Historic American Buildings Survey C.W.J. Johnson's Views of California ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. Historic American Buildings Survey C.W.J. Johnson's Views of California Scenery - Ed Grabhorn's Collection San Francisco, California About 1870 - Mission San Carlos Borromeo, Rio Road & Lausen Drive, Carmel-by-the-Sea, Monterey County, CA

Comparative biology of Uncinaria spp. in the California sea lion (Zalophus californianus) and the northern fur seal (Callorhinus ursinus) in California.

PubMed

Lyons, E T; DeLong, R L; Gulland, F M; Melin, S R; Tolliver, S C; Spraker, T R

2000-12-01

Studies on several aspects of the life cycle of hookworms (Uncinaria spp.) in the California sea lion (Zalophus californianus) and northern fur seal (Callorhinus ursinus) were conducted on material collected on San Miguel Island (SMI), California and at The Marine Mammal Center, Sausalito, California in 1997, 1998, and 1999. Examination of Z. californianus intestines for adult hookworms and feces for eggs revealed that longevity of these parasites in pups is about 6-8 mo, and infections are probably not present in older sea lions. Parasitic third-stage larvae (L3) were recovered from the ventral abdominal tissue of Z. californianus, suggesting transmammary transmission. Callorhinus ursinus pups had no hookworm eggs in their feces or adult worms (except for 1 probable contaminant) in their intestines in the fall and early winter, revealing that adult Uncinaria spp. are spontaneously lost at <3 mo of age of the pups. Sand samples from rookeries, used by both Z. californianus and C. ursinus, on SMI were negative for free-living, L3 in summer months but positive in fall and winter months, indicating seasonality occurred.

Investigations of peritoneal and intestinal infections of adult hookworms (Uncinaria spp.) in northern fur seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups on San Miguel Island, California (2003).

PubMed

Lyons, Eugene T; Delong, R L; Nadler, S A; Laake, J L; Orr, A J; Delong, B L; Pagan, C

2011-09-01

The peritoneal cavity (PNC) and intestine of northern fur seal (Callorhinus ursinus) pups and California sea lion (Zalophus californianus) pups that died in late July and early August, 2003, on San Miguel Island, California, were examined for hookworms. Prevalence and morphometric studies were done with the hookworms in addition to molecular characterization. Based on this and previous molecular studies, hookworms from fur seals are designated as Uncinaria lucasi and the species from sea lions as Uncinaria species A. Adult hookworms were found in the PNC of 35 of 57 (61.4%) fur seal pups and of 13 of 104 (12.5%) sea lion pups. The number of hookworms located in the PNC ranged from 1 to 33 (median = 3) for the infected fur seal pups and 1 to 16 (median = 2) for the infected sea lion pups. In addition to the PNC, intestines of 43 fur seal and 32 sea lion pups were examined. All of these pups were positive for adult hookworms. The worms were counted from all but one of the sea lion pups. Numbers of these parasites in the intestine varied from 3 to 2,344 (median = 931) for the fur seal pups and 39 to 2,766 (median = 643) for the sea lion pups. Sea lion pups with peritoneal infections had higher intensity infections in the intestines than did pups without peritoneal infections, lending some support for the hypothesis that peritoneal infections result from high-intensity infections of adult worms. There was no difference in intestinal infection intensities between fur seal pups with and without peritoneal infections. Female adult hookworms in the intestines of both host species were significantly larger than males, and sea lion hookworms were larger than those in fur seals. Worms in the intestine also were larger than worms found in the PNC. Gene sequencing and (RFLP) analysis of (PCR) amplified (ITS) ribosomal DNA were used to diagnose the species of 172 hookworms recovered from the PNC and intestine of 18 C. ursinus and seven Z. californianus hosts. These molecular data revealed that U. lucasi (hookworm of C. ursinus) and Uncinaria species A (of Z. californianus) infrequently mature in the intestine of the opposite host species in California rookeries. However, there is no support from molecular data for the hypothesis that cross-infection with "the wrong" Uncinaria species is a contributing factor in these cases of host peritonitis. The major significance of this research is the unusual finding of adult hookworms in the PNC of so many dead pups. No obvious explanation for this occurrence could be determined. Further research, like in the present study, should help understand and monitor the apparent ever changing role of hookworm disease in the health of northern fur seal and California sea lion pups on SMI.

Dynamics and distribution of black abalone populations at San Nicolas Island

USGS Publications Warehouse

VanBlaricom, Glenn R.; Hochberg, F.G.

1993-01-01

Dense populations of black abalones (Haliotis cracherodii Leach) were monitored in permanent intertidal plots at nine sites on San Nicolas Island from 1981 through 1990. Densities were essentially constant at all four sites along the north shore of the island throughout the study period. Densities at five sites along the south shore were more variable, possibly reflecting asynchronous variation in recruitment, mortality resulting from wave disturbance, and removal by people. Temporal variation of abalone densities apparently was not influenced by sea otters or abalone withering syndrome during this study. Abalones were strongly aggregated in space. Highest densities occurred in areas of irregular substrata, apparently as a result of preference for crevices and vertical faces. The locations of dense patches were persistent in time.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballachey, B.E.; Kloecker, K.A.

Aliphatic and aromatic hydrocarbons were analyzed in hair, liver and intestinal samples taken from dead sea otters (Enhydra lutris) collected in spring and summer 1989 from Prince William Sound, the Kenai Peninsula and Kodiak Island, along the path of the Exxon Valdez oil spill. Hair showed significant differences in hydrocarbon concentrations among the three locations, but few significant differences were noted for liver or intestine samples. The highest concentrations of both aliphatic and aromatic hydrocarbons were measured in hair samples from Prince William Sound. Hydrocarbon concentrations in intestine and liver samples from the three locations were generally similar and low,more » suggesting that uptake into the tissues was limited, or that hydrocarbons within the tissues had been metabolized by the time samples were collected.« less

In situ cloud and aerosol measurements over Coastal Antarctica during intensive field campaigns in 2010, 2011 and 2015

NASA Astrophysics Data System (ADS)

O'Shea, Sebastian; Choularton, Tom; Flynn, Michael; Bower, Keith; Gallagher, Martin; Fleming, Zoe; Listowski, Constantino; Kirchgaessner, Amelie; Ladkin, Russell; Lachlan-Cope, Tom; Crosier, Jonathan

2017-04-01

Few direct measurements have been made of Antarctic aerosol and cloud properties. As a result, a number of studies have suggested they are poorly represented within weather/climate models. This has important consequences for predictions of the mass balance of the Antarctic ice sheet and both weather patterns in the region and worldwide. In situ measurements of cloud and aerosol properties were collected over the Antarctic Peninsula, coastal continent and Weddell Sea during intensive observation periods in 2010, 2011 and 2015. Airborne measurements were collected using British Antarctic Survey's instrumented Twin Otter research aircraft for all 3 campaigns and additional ground based measurements were made at Halley's Clean Air Sector Laboratory in 2015. This presentation will focus on the aerosol measurements from these intensive observation periods. The aerosol in the region was found to have strong vertical gradients and to be hygroscopic in nature. The hygroscopicity parameter, κ had a mean value during the 2015 campaign of 0.69, which is consistent with other remote marine locations that are dominated by sea spray emissions. Aerosol properties will be investigated in terms of their air mass history. The relative contribution of emissions from the Antarctic Continent, sea ice and Sea/Ocean regions will be examined. The ice nucleating properties of the aerosol will also be discussed.

42. Peaks of Otter, Abbott Lake. View across lake to ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

42. Peaks of Otter, Abbott Lake. View across lake to peaks of Outter Lodge, completed in 1964. Construction of the lake got underway in 1964. Looking east-northeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

Nature Photography - Otter

NASA Image and Video Library

2017-01-04

An otter swims through a waterway at NASA's Kennedy Space Center in Florida. The center shares a border with the Merritt Island National Wildlife Refuge. More than 330 native and migratory bird species, 25 mammals, 117 fishes and 65 amphibians and reptiles call Kennedy and the wildlife refuge home.

Mercury concentrations in wild mink (Mustela vison) and river otters (Lontra canadensis) collected from eastern and Atlantic Canada: relationship to age and parasitism.

PubMed

Klenavic, Katherine; Champoux, Louise; Mike, O'Brien; Daoust, Pierre-Y; Evans, R Douglas; Evans, Hayla E

2008-11-01

Total mercury (Hg) concentrations were measured in the fur, brain and liver of wild mink (Mustela vison) and river otters (Lontra canadensis) collected from eastern and Atlantic Canada. Total Hg concentrations in fur were strongly correlated with levels in the brain and liver. There was no difference in tissue concentrations between male and female mink; however, female otters had significantly higher fur, brain and liver Hg levels than males. Similarly, there was not a significant relationship between Hg concentration and age of mink, whereas in otters, Hg concentrations in all three tissues decreased significantly with age. In both species, only a very small percentage of the variability in Hg concentration was explained by age. After adjusting the data for site-to-site differences in Hg levels, Hg concentrations in the fur of mink infected by the parasite, Dioctophyma renale, were found to be significantly higher than Hg levels in uninfected mink.

Trace elements and pesticides in Salton Sea area, California

USGS Publications Warehouse

Schroeder, Roy A.; Setmire, James G.; Wolfe, John C.

1988-01-01

Concentrations of numerous potentially toxic trace elements and pesticides were determined in water, sediment, and biota from the Salton Sea area in southestern California. Comparison of results with data from other studies in this area and from other areas, and with various water-quality standards or criteria, indicate that selenium probably is the principal contaminant of concern in the Salton Sea basin and that it probably is related to agricultural practices. Selenium is mobilized in the subsurface drainwater produced by agricultural irrigation and transported in ditches and rivers, some of which pass through or near the Salton Sea National Wildlife Refuge before entering the Salton Sea. Some selenium apparently is incorporated into the food chain. In response to the finding of elevated selenium residues in fish from the area by State agencies, the Imperial County Health Department has issued a health advisory restricting or prohibiting human consumption of fish from the Salton Sea and drains.

Infection of California sea lions (Zalophus californianus) with terrestrial Brucella spp.

PubMed

Avalos-Téllez, Rosalía; Ramírez-Pfeiffer, Carlos; Hernández-Castro, Rigoberto; Díaz-Aparicio, Efrén; Sánchez-Domínguez, Carlos; Zavala-Norzagaray, Alan; Arellano-Reynoso, Beatriz; Suárez-Güemes, Francisco; Aguirre, A Alonso; Aurioles-Gamboa, David

2014-10-01

Infections with Brucella ceti and pinnipedialis are prevalent in marine mammals worldwide. A total of 22 California sea lions (Zalophus californianus) were examined to determine their exposure to Brucella spp. at San Esteban Island in the Gulf of California, Mexico, in June and July 2011. Although samples of blood, vaginal mucus and milk cultured negative for these bacteria, the application of rose Bengal, agar gel immunodiffusion, PCR and modified fluorescence polarization assays found that five animals (22.7%) had evidence of exposure to Brucella strains. The data also suggested that in two of these five sea lions the strains involved were of terrestrial origin, a novel finding in marine mammals. Further work will be required to validate and determine the epidemiological significance of this finding. Copyright © 2014 Elsevier Ltd. All rights reserved.

Parcel-scale urban coastal flood mapping: Leveraging the multi-scale CoSMoS model for coastal flood forecasting

NASA Astrophysics Data System (ADS)

Gallien, T.; Barnard, P. L.; Sanders, B. F.

2011-12-01

California coastal sea levels are projected to rise 1-1.4 meters in the next century and evidence suggests mean tidal range, and consequently, mean high water (MHW) is increasing along portions of Southern California Bight. Furthermore, emerging research indicates wind stress patterns associated with the Pacific Decadal Oscillation (PDO) have suppressed sea level rise rates along the West Coast since 1980, and a reversal in this pattern would result in the resumption of regional sea level rise rates equivalent to or exceeding global mean sea level rise rates, thereby enhancing coastal flooding. Newport Beach is a highly developed, densely populated lowland along the Southern California coast currently subject to episodic flooding from coincident high tides and waves, and the frequency and intensity of flooding is expected to increase with projected future sea levels. Adaptation to elevated sea levels will require flood mapping and forecasting tools that are sensitive to the dominant factors affecting flooding including extreme high tides, waves and flood control infrastructure. Considerable effort has been focused on the development of nowcast and forecast systems including Scripps Institute of Oceanography's Coastal Data Information Program (CDIP) and the USGS Multi-hazard model, the Southern California Coastal Storm Modeling System (CoSMoS). However, fine scale local embayment dynamics and overtopping flows are needed to map unsteady flooding effects in coastal lowlands protected by dunes, levees and seawalls. Here, a recently developed two dimensional Godunov non-linear shallow water solver is coupled to water level and wave forecasts from the CoSMoS model to investigate the roles of tides, waves, sea level changes and flood control infrastructure in accurate flood mapping and forecasting. The results of this study highlight the important roles of topographic data, embayment hydrodynamics, water level uncertainties and critical flood processes required for meaningful prediction of sea level rise impacts and coastal flood forecasting.

A cool eastern Pacific Ocean at the close of the Last Interglacial complex

USGS Publications Warehouse

Muhs, D.R.; Simmons, K.R.; Kennedy, G.L.; Ludwig, K. R.; Groves, L.T.

2006-01-01

New high-precision thermal ionization mass-spectrometric (TIMS) U-series ages of solitary corals (Balanophyllia elegans) from several marine terrace localities along the California and southern Oregon coasts date to the ???80,000 yr BP high stand of sea, correlative with marine isotope substage 5a, late in the last interglacial complex. Ages of multiple corals from localities north of Point An??o Nuevo (central California) and San Nicolas Island (southern California) suggest that this high sea stand could have lasted at least 8000 yr, from ???84,000 to ???76,000 yr BP. These ages overlap with those from marine deposits on tectonically stable Bermuda and tectonically emergent Barbados. Higher-elevation terraces at two California localities, in the Palos Verdes Hills and on San Nicolas Island, have corals with ages that range mostly from ???121,000 to ???116,000 yr BP, correlative with marine isotope substage 5e. These ages are similar to those reported for other terraces in southern California but are younger than some ages reported from Hawaii, Barbados and the Bahamas. Marine terrace faunas are excellent proxies for nearshore marine paleotemperatures during past high sea stands. Terraces on the Palos Verdes Hills and San Nicolas Island dated to the ???120,000 yr BP high sea stand have dominantly zoogeographically "neutral" species in exposed coastal localities, indicating nearshore waters similar to those of today. In contrast, ???80,000 yr BP, exposed coastal localities typically have molluscan faunas characterized by numerous extralimital northern species and a lack of extralimital southern species. These fossil assemblages are indicative of nearshore water temperatures that were cooler than modern temperatures at ???80,000 yr BP. Waters at least as warm as today's at ???120,000 yr BP and cooler than present at ???80,000 yr BP are in excellent agreement with marine alkenone records and coastal vegetation records derived from pollen data, from both southern and northern California. Decreased insolation or increased upwelling seem inadequate to explain the cool waters off the Pacific Coast from southern Oregon to southern California at ???80,000 yr BP. We propose that a stronger California Current (or at least one with a greater component of subarctic waters) may explain cooler-than-modern coastal waters during the ???80,000 yr BP high sea stand. ?? 2005 Elsevier Ltd. All rights reserved.

Hydrology and physiography of the Salton Sea, California

USGS Publications Warehouse

Littlefield, W.M.

1966-01-01

The increased utilization of the Salton Sea and its shore for recreation, the development of residential complexes on its shore, and the encroachment of the sea into these developments have emphasized the need for a concise summary of hydrologic and physiographic information concerning the area. This report attempts to fill that need.The report was authorized by a cooperative agreement between the U.S. Geological Survey and the California Department of Water Resources. It was prepared under the general direction of Walter Hofmann, district chief of the Water Resources Division of the Geological Survey, at Menlo Park. 

Two novel noroviruses and a novel norovirus genogroup in California sea lions.

PubMed

Teng, Jade L L; Martelli, Paolo; Chan, Wan-Mui; Lee, Hwei Huih; Hui, Suk-Wai; Lau, Candy C Y; Tse, Herman; Yuen, Kwok-Yung; Lau, Susanna K P; Woo, Patrick C Y

2018-06-01

In this study, two novel noroviruses (NoVs) were discovered from faecal samples from California sea lions from an oceanarium in Hong Kong, and named California sea lion NoV 1 (Csl/NoV1) and California sea lion NoV 2 (Csl/NoV2). Whole-genome sequencing showed that the genome organization and amino acid motifs of both Csl/NoV1 and Csl/NoV2 were typical of those of other NoVs in their open reading frames (ORFs). Csl/NoV1 possessed only 52.6-52.8 % amino acid identity in VP1 to the closest matches in genogroup GII. Therefore, Csl/NoV1 should constitute a novel genogroup of NoV. Shifting of the phylogenetic position of Csl/NoV1 in the RdRp, VP1 and VP2 trees was observed, which may have been due to recombination events and/or biased mutations. Csl/NoV2 possessed 55.4-56.2 % amino acid identity in VP1 to its closest relatives in genogroup GVI, which means that it represents a new genotype in genogroup GVI. Further studies will reveal what diseases these NoVs can cause in marine mammals.

Common cancer in a wild animal: the California sea lion (Zalophus californianus) as an emerging model for carcinogenesis.

PubMed

Browning, Helen M; Gulland, Frances M D; Hammond, John A; Colegrove, Kathleen M; Hall, Ailsa J

2015-07-19

Naturally occurring cancers in non-laboratory species have great potential in helping to decipher the often complex causes of neoplasia. Wild animal models could add substantially to our understanding of carcinogenesis, particularly of genetic and environmental interactions, but they are currently underutilized. Studying neoplasia in wild animals is difficult and especially challenging in marine mammals owing to their inaccessibility, lack of exposure history, and ethical, logistical and legal limits on experimentation. Despite this, California sea lions (Zalophus californianus) offer an opportunity to investigate risk factors for neoplasia development that have implications for terrestrial mammals and humans who share much of their environment and diet. A relatively accessible California sea lion population on the west coast of the USA has a high prevalence of urogenital carcinoma and is regularly sampled during veterinary care in wildlife rehabilitation centres. Collaborative studies have revealed that genotype, persistent organic pollutants and a herpesvirus are all associated with this cancer. This paper reviews research to date on the epidemiology and pathogenesis of urogenital carcinoma in this species, and presents the California sea lion as an important and currently underexploited wild animal model of carcinogenesis. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Nature Photography - Otter

NASA Image and Video Library

2016-12-13

An otter makes its way into the underbrush at NASA's Kennedy Space Center in Florida. The center shares a border with the Merritt Island National Wildlife Refuge. More than 330 native and migratory bird species, 25 mammals, 117 fishes and 65 amphibians and reptiles call Kennedy and the wildlife refuge home.

The last interglacial period on the Pacific Coast of North America: Timing and paleoclimate

USGS Publications Warehouse

Muhs, D.R.; Simmons, K.R.; Kennedy, G.L.; Rockwell, T.K.

2002-01-01

New, high-precision U-series ages of solitary corals (Balanophyllia elegans) coupled with molluscan faunal data from marine terraces on the Pacific Coast of North America yield information about the timing and warmth of the last interglacial sea-level highstand. Balanophyllia elegans takes up U in isotopic equilibrium with seawater during growth and shortly after death. Corals from the second terrace on San Clemente Island (offshore southern California), the third terrace on Punta Banda (on the Pacific Coast of northern Baja California), and the Discovery Point Formation on Isla de Guadalupe (in the Pacific Ocean offshore Baja California) date to the peak of the last interglacial period and have U-series ages ranging from ca. 123 to 114 ka. The first terrace on Punta Banda has corals with ages ranging from ca. 83 to 80 ka, which corresponds to a sea-level highstand formed in the late last interglacial period. U-series analyses of corals from the Cayucos terrace (central California) and the Nestor terrace at Point Loma (southern California) show that these fossils have evidence of open-system history, similar to what has been reported by other workers for the same localities. Nevertheless, a model of continuous, secondary U and Th uptake shows that two ages of corals are likely present at these localities, representing the ca. 105 and ca. 120 ka sea-level highstands reported elsewhere. U-series ages of last interglacial corals from the Pacific Coast overlap with, but are on average younger than the ages of corals from Barbados, the Bahamas, and Hawaii. This age difference is explained by the nature of the geomorphic response to sea-level change: fringing or barrier reefs on low-latitude coastlines have an accretionary growth style that keeps pace with rising sea level, whether on a tectonically rising or stable coastline. In contrast, midlatitude, high-energy coastlines are sites of platform cutting during the early part of a sea-level high stand and terrace scouring and concomitant sediment and fossil deposition as sea level starts to recede. The youngest ages of corals from the Pacific Coast suggest that sea level was still relatively high at ca. 116 ka, which is not in agreement with other estimates of relatively large global ice volume at that time. Reliably dated, ca. 120 ka marine-terrace deposits on the Pacific Coast have fossil mollusks that indicate water temperatures as warm or warmer than at present. In contrast, ca. 80 ka marine deposits reported here and elsewhere have fossil mollusks indicating cooler-than-modern water temperatures. The presence of both ca. 105 ka and ca. 120 ka corals on the Nestor and Cayucos terraces explains a previously enigmatic mixture of warm-water and cool-water mollusks. At ca. 105 ka, a relatively high sea level with cool waters may have "captured" the terrace formed during the 120 ka sea-level highstand, in areas of low uplift rate. The inference of cooler-than-modern waters off the Pacific Coast of North America at ca. 80 ka and ca. 105 ka, based on marine-terrace faunas, does not agree with estimates of sea-surface temperatures derived from alkenone studies in the Santa Barbara Basin. However, cooler water temperatures at these times are in agreement with paleo-temperature estimates from planktonic foraminiferal data for the Santa Barbara Basin. All records, from central California to Baja California, whether from marine terraces or offshore cores, indicate at least seasonably warmer-than-modern waters during the peak of the last interglacial period at ca. 120 ka.

IDENTIFICATION OF TWO NOVEL COCCIDIAN SPECIES SHED BY CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS)

PubMed Central

Carlson-Bremer, Daphne; Johnson, Christine K.; Miller, Robin H.; Gulland, Frances M. D.; Conrad, Patricia A.; Wasmuth, James D.; Colegrove, Kathleen M.

2016-01-01

Routine fecal examination revealed novel coccidian oocysts in asymptomatic California sea lions (Zalophus californianus) in a rehabilitation facility. Coccidian oocysts were observed in fecal samples collected from 15 of 410 California sea lions admitted to The Marine Mammal Center between April 2007 and October 2009. Phylogenetic analysis using the full ITS-1 region, partial small subunit 18S rDNA sequence, and the Apicomplexa rpoB region identified 2 distinct sequence clades, referred to as Coccidia A and Coccidia B, and placed them in the Sarcocystidae, grouped with the tissue-cyst–forming coccidia. Both sequence clades resolved as individual taxa at ITS-1 and rpoB and were most closely related to Neospora caninum. Coccidia A was identified in 11 and Coccidia B in 4 of 12 sea lion oocyst samples successfully sequenced (3 of those sea lions were co-infected with both parasites). Shedding of Coccidia A oocysts was not associated with age class, sex, or stranding location, but yearlings represented the majority of shedders (8/15). This is the first study to use molecular phylogenetics to identify and describe coccidian parasites shed by a marine mammal. PMID:22091999

Identification of two novel coccidian species shed by California sea lions (Zalophus californianus).

PubMed

Carlson-Bremer, Daphne; Johnson, Christine K; Miller, Robin H; Gulland, Frances M D; Conrad, Patricia A; Wasmuth, James D; Colegrove, Kathleen M; Grigg, Michael E

2012-04-01

Routine fecal examination revealed novel coccidian oocysts in asymptomatic California sea lions (Zalophus californianus) in a rehabilitation facility. Coccidian oocysts were observed in fecal samples collected from 15 of 410 California sea lions admitted to The Marine Mammal Center between April 2007 and October 2009. Phylogenetic analysis using the full ITS-1 region, partial small subunit 18S rDNA sequence, and the Apicomplexa rpoB region identified 2 distinct sequence clades, referred to as Coccidia A and Coccidia B, and placed them in the Sarcocystidae, grouped with the tissue-cyst-forming coccidia. Both sequence clades resolved as individual taxa at ITS-1 and rpoB and were most closely related to Neospora caninum. Coccidia A was identified in 11 and Coccidia B in 4 of 12 sea lion oocyst samples successfully sequenced (3 of those sea lions were co-infected with both parasites). Shedding of Coccidia A oocysts was not associated with age class, sex, or stranding location, but yearlings represented the majority of shedders (8/15). This is the first study to use molecular phylogenetics to identify and describe coccidian parasites shed by a marine mammal.

76 FR 30309 - Marine Mammals; File No. 16087

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-25

... authorizes taking marine mammals in California, Oregon, and Washington to investigate population status, health, demographic parameters, life history and foraging ecology of California sea lions (Zalophus...

The role of internal variability in prolonging the California drought

NASA Astrophysics Data System (ADS)

Buenning, N. H.; Stott, L. D.

2015-12-01

The current drought in California has been one of the driest on record. Using atmospheric general circulation models (AGCMs), recent studies have demonstrated that the low precipitation anomalies observed during the first three winters of the current drought are mostly attributable to changes in sea surface temperature (SST) and sea ice forcing. Here we show through AGCM simulations that the fourth and latest winter of the current drought is not attributable to SST and sea ice forcing, but instead a consequence of higher internal variability. Using the Global Spectral Model (GSM) we demonstrate how the surface forcing reproduces dry conditions over California for the first three winters of the current drought, similar to what other models produced. However, when forced with the SST and sea ice conditions for the winter of 2014-2015, GSM robustly simulates high precipitation conditions over California. This significantly differs with observed precipitation anomalies, which suggests a model deficiency or large influence of internal variability within the climate system during the winter of 2014-2015. Ensemble simulations with 234 realizations reveal that the surface forcing created a broader range of precipitation possibilities over California. Thus, the surface forcing caused a greater degree of internal variations, which was driven by a reduced latitudinal temperature gradient and amplified planetary waves over the Pacific. Similar amplified waves are also seen in 21st century climate projections of upper-level geopotential heights, suggesting that 21st century precipitation over California will become more variable and increasingly difficult to predict on seasonal timescales. When an El Nino pattern is applied to the surface forcing the precipitation further increases and the variance amongst model realizations is reduced, which indicates a strong likelihood of an anomalously wet 2015-2016 winter season.

76 FR 26255 - Marine Mammals; File No. 116-1691

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-06

... hereby given that Sea World LLC, Sea World of San Diego, 500 SeaWorld Drive, San Diego, California 92109... Ocean Blvd., Suite 4200, Long Beach, CA 90802-4213; phone (562) 980-4001; fax (562) 980-4018. FOR...

NASA COAST and OCEANIA Airborne Missions Support Ecosystem and Water Quality Research in the Coastal Zone

NASA Technical Reports Server (NTRS)

Guild, Liane; Kudela, Raphael; Hooker, Stanford; Morrow, John; Russell, Philip; Palacios, Sherry; Livingston, John M.; Negrey, Kendra; Torres-Perez, Juan; Broughton, Jennifer

2014-01-01

NASA has a continuing requirement to collect high-quality in situ data for the vicarious calibration of current and next generation ocean color satellite sensors and to validate the algorithms that use the remotely sensed observations. Recent NASA airborne missions over Monterey Bay, CA, have demonstrated novel above- and in-water measurement capabilities supporting a combined airborne sensor approach (imaging spectrometer, microradiometers, and a sun photometer). The results characterize coastal atmospheric and aquatic properties through an end-to-end assessment of image acquisition, atmospheric correction, algorithm application, plus sea-truth observations from state-of-the-art instrument systems. The primary goal is to demonstrate the following in support of calibration and validation exercises for satellite coastal ocean color products: 1) the utility of a multi-sensor airborne instrument suite to assess the bio-optical properties of coastal California, including water quality; and 2) the importance of contemporaneous atmospheric measurements to improve atmospheric correction in the coastal zone. The imaging spectrometer (Headwall) is optimized in the blue spectral domain to emphasize remote sensing of marine and freshwater ecosystems. The novel airborne instrument, Coastal Airborne In-situ Radiometers (C-AIR) provides measurements of apparent optical properties with high dynamic range and fidelity for deriving exact water leaving radiances at the land-ocean boundary, including radiometrically shallow aquatic ecosystems. Simultaneous measurements supporting empirical atmospheric correction of image data are accomplished using the Ames Airborne Tracking Sunphotometer (AATS-14). Flight operations are presented for the instrument payloads using the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter flown over Monterey Bay during the seasonal fall algal bloom in 2011 (COAST) and 2013 (OCEANIA) to support bio-optical measurements of phytoplankton for coastal zone research.

Eagles, Otters, and Unicorns: An Anatomy of Innovation.

ERIC Educational Resources Information Center

Grossman, Stephen R.; King, Margaret J.

1990-01-01

This article describes three archetypal workers: eagles who innovate by improvements, otters who innovate by extension, and unicorns who innovate by paradigm. Each of these innovators is discussed in terms of domain-relevant skills, manipulative skills, and motivation. Needs of each type in terms of business culture are discussed. (PB)

California State Waters Map Series—Offshore of Santa Cruz, California

USGS Publications Warehouse

Cochrane, Guy R.; Dartnell, Peter; Johnson, Samuel Y.; Erdey, Mercedes D.; Golden, Nadine E.; Greene, H. Gary; Dieter, Bryan E.; Hartwell, Stephen R.; Ritchie, Andrew C.; Finlayson, David P.; Endris, Charles A.; Watt, Janet T.; Davenport, Clifton W.; Sliter, Ray W.; Maier, Katherine L.; Krigsman, Lisa M.; Cochrane, Guy R.; Cochran, Susan A.

2016-03-24

IntroductionIn 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow subsurface geology.The Offshore of Santa Cruz map area is located in central California, on the Pacific Coast about 98 km south of San Francisco. The city of Santa Cruz (population, about 63,000), the largest incorporated city in the map area and the county seat of Santa Cruz County, lies on uplifted marine terraces between the shoreline and the northwest-trending Santa Cruz Mountains, part of California’s Coast Ranges. All of California’s State Waters in the map area is part of the Monterey Bay National Marine Sanctuary.The map area is cut by an offshore section of the San Gregorio Fault Zone, and it lies about 20 kilometers southwest of the San Andreas Fault Zone. Regional folding and uplift along the coast has been attributed to a westward bend in the San Andreas Fault Zone and to right-lateral movement along the San Gregorio Fault Zone. Most of the coastal zone is characterized by low, rocky cliffs and sparse, small pocket beaches backed by low, terraced hills. Point Santa Cruz, which forms the north edge of Monterey Bay, provides protection for the beaches in the easternmost part of the map area by sheltering them from the predominantly northwesterly waves.The shelf in the map area is underlain by variable amounts (0 to 25 m) of upper Quaternary shelf, estuarine, and fluvial sediments deposited as sea level fluctuated in the late Pleistocene. The inner shelf is characterized by bedrock outcrops that have local thin sediment cover, the result of regional uplift, high wave energy, and limited sediment supply. The midshelf occupies part of an extensive, shore-parallel mud belt. The thickest sediment deposits, inferred to consist mainly of lowstand nearshore deposits, are found in the southeastern and northwestern parts of the map area.Coastal sediment transport in the map area is characterized by northwest-to-southeast littoral transport of sediment that is derived mainly from ephemeral streams in the Santa Cruz Mountains and also from local coastal-bluff erosion. During the last approximately 300 years, as much as 18 million cubic yards (14 million cubic meters) of sand-sized sediment has been eroded from the area between Año Nuevo Island and Point Año Nuevo and transported south; this mass of eroded sand is now enriching beaches in the map area. Sediment transport is within the Santa Cruz littoral cell, which terminates in the submarine Monterey Canyon.Benthic species observed in the Offshore of Santa Cruz map area are natives of the cold-temperate biogeographic zone that is called either the “Oregonian province” or the “northern California ecoregion.” This biogeographic province is maintained by the long-term stability of the southward-flowing California Current, the eastern limb of the North Pacific subtropical gyre that flows from southern British Columbia to Baja California. At its midpoint off central California, the California Current transports subarctic surface (0–500 m deep) waters southward, about 150 to 1,300 km from shore. Seasonal northwesterly winds that are, in part, responsible for the California Current, generate coastal upwelling. The south end of the Oregonian province is at Point Conception (about 300 km south of the map area), although its associated phylogeographic group of marine fauna may extend beyond to the area offshore of Los Angeles in southern California. The ocean off of central California has experienced a warming over the last 50 years that is driving an ecosystem shift away from the productive subarctic regime towards a depopulated subtropical environment.Biological productivity resulting from coastal upwelling supports populations of Sooty Shearwater, Western Gull, Common Murre, Cassin’s Auklet, and many other less populous bird species. In addition, an observable recovery of Humpback and Blue Whales has occurred in the area; both species are dependent on coastal upwelling to provide nutrients. The large extent of exposed inner shelf bedrock supports large forests of “bull kelp,” which is well adapted for high-wave-energy environments. The kelp beds are the northernmost known habitat for the population of southern sea otters. Common fish species found in the kelp beds and rocky reefs include lingcod and various species of rockfish and greenling.