Science.gov

Sample records for california sea otters

  1. Population status of California sea otters

    SciTech Connect

    Not Available

    1988-11-30

    The main objective of the study was to develop a simulation model to facilitate analysis of the risk of oil spills to the threatened California sea otter population. Existing data on the dynamics and demography of the population were synthesized. The additional data needed for model development were collected through radiotelemetry studies of sea otters in Alaska and California. The simulation model contains four interrelated stochastic submodels: a short-term population model, a long-term population model, a sea otter distribution model, and a sea otter movement model. The report includes a detailed description of the model, the data on which it is based, and an operating manual.

  2. Comparison of organochlorine contaminants among sea otter (Enhydra lutris) populations in California and Alaska

    SciTech Connect

    Bacon, C.E.; Jarman, W.M.; Estes, J.A.; Simon, M.; Norstrom, R.J.

    1999-03-01

    Organochlorine pesticides, polychlorinated biphenyls (PCBs) including non-ortho PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) were measured in sea otter liver tissue from California, southeast Alaska, and the western Aleutian archipelago collected between 1988 and 1992. Average total dichlorodiphenyltrichloroethane concentrations for California otters were over 20 times higher than in Aleutian otters and over 800 times higher than otters from southeast Alaska. Levels for total PCBs in Aleutian otters were 1.7 times higher than levels in California otters and 38 times higher than otters from southeast Alaska. Levels for PCDD and PCDF were extremely low in all otter populations. Levels of PCBs in Aleutian and Californian otters are abnormally high when compared with southeast Alaskan otters. The source of PCBs to the Aleutian Islands remains unclear and vital to understanding the potential impacts to sea otters.

  3. Bartonella spp. Exposure in Northern and Southern Sea Otters in Alaska and California

    PubMed Central

    Chomel, Bruno B.; Gill, Verena A.; Doroff, Angela M.; Miller, Melissa A.; Burek-Huntington, Kathleen A.; Kasten, Rickie W.; Byrne, Barbara A.; Goldstein, Tracey; Mazet, Jonna A.K.

    2014-01-01

    Abstract Since 2002, an increased number of northern sea otters (Enhydra lutris kenyoni) from southcentral Alaska have been reported to be dying due to endocarditis and/or septicemia with infection by Streptococcus infantarius subsp. coli. Bartonella spp. DNA was also detected in northern sea otters as part of mortality investigations during this unusual mortality event (UME) in Kachemak Bay, Alaska. To evaluate the extent of exposure to Bartonella spp. in sea otters, sera collected from necropsied and live-captured northern sea otters, as well as necropsied southern sea otters (Enhydra lutris nereis) unaffected by the UME, were analyzed using an immunofluorescent antibody assay. Antibodies against Bartonella spp. were detected in sera from 50% of necropsied and 34% of presumed healthy, live-captured northern sea otters and in 16% of necropsied southern sea otters. The majority of sea otters with reactive sera were seropositive for B. washoensis, with antibody titers ranging from 1:64 to 1:256. Bartonella spp. antibodies were especially common in adult northern sea otters, both free-living (49%) and necropsied (62%). Adult stranded northern sea otters that died from infectious causes, such as opportunistic bacterial infections, were 27 times more likely to be Bartonella seropositive than adult stranded northern sea otters that died from noninfectious causes (p<0.001; 95% confidence interval 2.62–269.4). Because Bartonella spp. antibodies were detected in necropsied northern sea otters from southcentral (44%) and southwestern (86%) stocks of Alaska, as well as in necropsied southern sea otters (16%) in southcentral California, we concluded that Bartonella spp. exposure is widely distributed among sea otter populations in the Eastern Pacific, providing context for investigating future disease outbreaks and monitoring of Bartonella infections for sea otter management and conservation. PMID:25514118

  4. Bartonella spp. exposure in northern and southern sea otters in Alaska and California.

    PubMed

    Carrasco, Sebastian E; Chomel, Bruno B; Gill, Verena A; Doroff, Angela M; Miller, Melissa A; Burek-Huntington, Kathleen A; Kasten, Rickie W; Byrne, Barbara A; Goldstein, Tracey; Mazet, Jonna A K

    2014-12-01

    Since 2002, an increased number of northern sea otters (Enhydra lutris kenyoni) from southcentral Alaska have been reported to be dying due to endocarditis and/or septicemia with infection by Streptococcus infantarius subsp. coli. Bartonella spp. DNA was also detected in northern sea otters as part of mortality investigations during this unusual mortality event (UME) in Kachemak Bay, Alaska. To evaluate the extent of exposure to Bartonella spp. in sea otters, sera collected from necropsied and live-captured northern sea otters, as well as necropsied southern sea otters (Enhydra lutris nereis) unaffected by the UME, were analyzed using an immunofluorescent antibody assay. Antibodies against Bartonella spp. were detected in sera from 50% of necropsied and 34% of presumed healthy, live-captured northern sea otters and in 16% of necropsied southern sea otters. The majority of sea otters with reactive sera were seropositive for B. washoensis, with antibody titers ranging from 1:64 to 1:256. Bartonella spp. antibodies were especially common in adult northern sea otters, both free-living (49%) and necropsied (62%). Adult stranded northern sea otters that died from infectious causes, such as opportunistic bacterial infections, were 27 times more likely to be Bartonella seropositive than adult stranded northern sea otters that died from noninfectious causes (p<0.001; 95% confidence interval 2.62-269.4). Because Bartonella spp. antibodies were detected in necropsied northern sea otters from southcentral (44%) and southwestern (86%) stocks of Alaska, as well as in necropsied southern sea otters (16%) in southcentral California, we concluded that Bartonella spp. exposure is widely distributed among sea otter populations in the Eastern Pacific, providing context for investigating future disease outbreaks and monitoring of Bartonella infections for sea otter management and conservation. PMID:25514118

  5. Lumber spill in central California waters: implications for oil spills and sea otters

    SciTech Connect

    VanBlaricom, G.R.; Jameson, R.J.

    1982-03-19

    A large quantity of lumber was spilled in the ocean off central California during the winter of 1978, and it spread through most of the range of the threatened California sea otter population within 4 weeks. The movement rates of lumber were similar to those of oil slicks observed elsewhere. These observations indicate that a major oil spill could expose significant numbers of California sea otters to oil contamination.

  6. 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…

  7. Some factors affecting the oil-spill risk to sea otters in California. Final report

    SciTech Connect

    Tinney, R.T.

    1984-10-01

    Sea otters in California, with their limited range and numbers, are exposed to the threat of oil spills from a number of sources including offshore oil and gas development, transportation of crude oil and refined products, and the bunker fuel of vessels transiting the otter range. This report explores some of the direct and indirect ways otters may be affected by oil spills, including hypothermia, pneumonia, toxic effects, and destruction of preferred prey. The report also examines the possibility of mitigating the effects of oil spills through spill containment and cleanup, otter capture, cleaning and rehabilitation, and otter relocation. The report concludes with a description of the amount of shoreline affected by some major spills in various parts of the world.

  8. Dramatic increase in sea otter mortality from white sharks in California

    USGS Publications Warehouse

    Tinker, M. Tim; Hatfield, Brian B.; Harris, Michael D.; Ames, Jack A.

    2016-01-01

    Although southern sea otters (Enhydra lutris nereis) are not considered prey for white sharks (Carcharodon carcharias), sharks do nonetheless bite sea otters. We analyzed spatial and temporal trends in shark bites on sea otters in California, assessing the frequency of shark bite wounds in 1,870 carcasses collected since 1985. The proportion of stranded sea otters having shark bites has increased sharply since 2003, and white shark bites now account for >50% of recovered carcasses. The trend was most pronounced in the southern part of the range, from Estero Bay to Point Conception, where shark bite frequency has increased eightfold. Seasonal trends were also evident: most shark-bitten carcasses are recovered in late summer and fall; however, the period of elevated shark bite frequency has lengthened. The causes of these trends are unclear, but possible contributing factors include increased white shark abundance and/or changes in white shark behavior and distribution. In particular, the spatiotemporal patterns of shark-bitten sea otters match increases in pinniped populations, and the increased availability of marine mammal prey for white sharks may have led to more sharks spending more time in nearshore waters utilized by both sea otters and pinnipeds.

  9. Butyltin residues in southern sea otters (Enhydra lutris nereis) found dead along California coastal waters

    USGS Publications Warehouse

    Kannan, K.; Guruge, K.S.; Thomas, N.J.; Tanabe, S.; Giesy, J.P.

    1998-01-01

    Tributyltin (TBT) and its degradation products, mono- (MBT) and dibutyltin (DBT), were determined in liver, kidney, and brain tissues of adult southern sea otters (Enhydra lutris nereis) found dead along the coast of California during 1992a??1996. Hepatic concentrations of butyltin compounds (BTs = MBT + DBT + TBT) ranged from 40 to 9200 ng/g wet wt, which varied depending on the sampling location and gender. Concentrations of BTs in sea otters were comparable to those reported in stranded bottlenose dolphins from the U.S. Atlantic Coast during 1989a??1994. Greater accumulation of butyltins in sea otters was explained by their bottom-feeding habit and the diet that consists exclusively of invertebrates such as mollusks and gastropods. Livers of female sea otters contained approximately 2-fold greater concentrations of BTs than did those of males. The composition of butyltin compounds in sea otter tissues was predominated by TBT in most cases and suggestive of recent exposure. Large harbors such as Monterey Harbor that handle ships legally painted with TBT-containing antifouling paints continued to experience ecotoxicologically significant butyltin contamination. Sea otters, which were affected by infectious diseases, contained greater concentrations of BTs in their tissues than those that died from trauma and other unknown causes.

  10. Chlorinated, brominated, and perfluorinated compounds, polycyclic aromatic hydrocarbons and trace elements in livers of sea otters from California, Washington, and Alaska (USA), and Kamchatka (Russia)

    USGS Publications Warehouse

    Kannan, K.; Moon, H.-B.; Yun, S.-H.; Agusa, T.; Thomas, N.J.; Tanabe, S.

    2008-01-01

    Concentrations of organochlorine pesticides (DDTs, HCHs, and chlordanes), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), perfluorinated compounds (PFCs), and 20 trace elements were determined in livers of 3- to 5-year old stranded sea otters collected from the coastal waters of California, Washington, and Alaska (USA) and from Kamchatka (Russia). Concentrations of organochlorine pesticides, PCBs, and PBDEs were high in sea otters collected from the California coast. Concentrations of DDTs were 10-fold higher in California sea otters than in otters from other locations; PCB concentrations were 5-fold higher, and PBDE concentrations were 2-fold higher, in California sea otters than in otters from other locations. Concentrations of PAHs were higher in sea otters from Prince William Sound than in sea otters from other locations. Concentrations of several trace elements were elevated in sea otters collected from California and Prince William Sound. Elevated concentrations of Mn and Zn in sea otters from California and Prince William Sound were indicative of oxidative stress-related injuries in these two populations. Concentrations of all of the target compounds, including trace elements, that were analyzed in sea otters from Kamchatka were lower than those found from the US coastal locations. ?? The Royal Society of Chemistry.

  11. Immunomodulatory effects upon in vitro exposure of California sea lion and southern sea otter peripheral blood leukocytes to domoic acid.

    PubMed

    Levin, Milton; Joshi, Dhanashree; Draghi, Andrew; Gulland, Frances M; Jessup, David; De Guise, Sylvain

    2010-04-01

    During red tide bloom events, the marine diatom Pseudo-nitzschia produces the toxin domoic acid (DA), which has been associated with stranding and mortality events involving California sea lions (Zalophus californianus) and southern sea otters (Enhydra lutris). In addition to these well-documented DA-induced neurotoxic events, there is increasing concern that DA may exert chronic effects, such as immunomodulation, which may potentially increase an individual's susceptibility to a number of opportunistic infections following nonlethal exposure. We investigated the effects of DA on innate (phagocytosis and respiratory burst) and adaptive (mitogen-induced lymphocyte proliferation) immune functions with the use of peripheral blood leukocytes collected from healthy California sea lions and southern sea otters upon in vitro exposure to 0 (unexposed control), 0.0001, 0.001, 0.01, 0.1, 1.0, 10, and 100 microM DA. Domoic acid did not significantly modulate phagocytosis or respiratory burst in either species. For California sea lions, DA significantly increased ConA-induced T-lymphocyte proliferation upon exposure to DA concentrations ranging from 0.0001 to 10 microM, resulting in a nonlinear dose-response curve. There was no effect on lymphocyte proliferation at the highest concentration of DA tested. No effects on lymphocyte proliferation were observed in southern sea otters. Importantly, the in vitro DA concentrations affecting T-cell proliferation were within or below the range of DA in serum measured in free-ranging California sea lions following natural exposure, suggesting a risk for immunomodulation in free-ranging animals. Understanding the risk for immunomodulation upon DA exposure will contribute in the health assessment and management of California sea lions and southern sea otters, as well as guide veterinarians and wildlife rehabilitators in caring for and treating afflicted animals. PMID:20688647

  12. Sea otter health: challenging a pet hypothesis

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  13. Sea otter health: Challenging a pet hypothesis

    PubMed Central

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission. PMID:26155464

  14. Sea otter health: Challenging a pet hypothesis.

    PubMed

    Lafferty, Kevin D

    2015-12-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission. PMID:26155464

  15. 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, D.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 (??13C and ??15N) 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 ??13C and ??15N 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

  16. Lead sources to California sea otters: Industrial inputs circumvent natural lead biodepletion mechanisms

    SciTech Connect

    Smith, D.R.; Flegal, A.R. ); Niemeyer, S. )

    1992-04-01

    Lead levels (as Pb/Ca atom ratios) and stable isotopic compositions were measured in teeth of preindustrial and contemporary California sea otters (Enhydra lutris) to determine if postindustrial changes had occurred in the magnitude and source of accumulated lead. Lead/calcium atom ratios in teeth of some contemporary animals were significantly elevated and compared to level in other contemporary and preindustrial otters. The isotopic ratios revealed a change in the sources of accumulated leads, from natural continental-derived lead in the preindustrial animals ({sup 207}Pb/{sup 206}Pb = 0.820 {plus minus} 0.002) to industrial sources dominated by aerosol lead in the contemporary otters ({sup 207}Pb/{sup 206}Pb = 0.853), who contained lead derived from an industrial waste lead deposit in Monterey Harbor. These data establish distinguishable sources of lead assimilated by sea otters, and indicate that elevated exposures to some animals circumvented the natural biodepletion of lead through marine trophic pathways.

  17. Coccidioidomycosis in southern sea otters

    USGS Publications Warehouse

    Thomas, Nancy J.; Pappagianis, Demosthenes; Creekmore, Lynn; 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.

  18. 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. PMID:25669450

  19. Behavior of sea otters in Washington and California

    USGS Publications Warehouse

    Jameson, R.J.

    2000-01-01

    These are databases on the population biology of the respective populations. They include data on movements, reproduction, foraging, and behavior. Data were obtained using known individuals either tagged, radio instrumented or both. California project ended in 1994. Washington work is ongoing. These data sets are located in Corvallis.

  20. 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.

  1. 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.

  2. 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

  3. Persistent organic pollutants in the blood of free-ranging sea otters (Enhydra lutris ssp.) in Alaska and California.

    PubMed

    Jessup, David A; Johnson, Christine K; Estes, James; Carlson-Bremer, Daphne; Jarman, Walter M; Reese, Stacey; Dodd, Erin; Tinker, M Tim; Ziccardi, Michael H

    2010-10-01

    As part of tagging and ecologic research efforts in 1997 and 1998, apparently healthy sea otters of four age-sex classes in six locations in Alaska and three in California were sampled for persistent organic pollutants (POPs) and other chemicals of ecologic or environmental concern (COECs). Published techniques for the detection of POPs (specifically ∑polychlorinated biphenyls [PCBs], ∑DDTs, ∑hexachlorocyclohexanes [HCHs], ∑polycyclic aromatic hydrocarbons [PAHs], ∑chlordanes [CHLs], hexachlorobenzene [HCB], dieldrin, and mirex) in the tissue of dead otters were modified for use with serum from live sea otters. Toxic equivalencies (TEQs) were calculated for POPs with proven bioactivity. Strong location effects were seen for most POPs and COECs; sea otters in California generally showed higher mean concentrations than those in Alaska. Differences in contaminant concentrations were detected among age and sex classes, with high levels frequently observed in subadults. Very high levels of ∑DDT were detected in male sea otters in Elkhorn Slough, California, where strong freshwater outflow from agricultural areas occurs seasonally. All contaminants except mirex differed among Alaskan locations; only ∑DDT, HCB, and chlorpyrifos differed within California. High levels of ∑PCB (particularly larger, more persistent congeners) were detected at two locations in Alaska where associations between elevated PCBs and military activity have been established, while higher PCB levels were found at all three locations in California where no point source of PCBs has been identified. Although POP and COEC concentrations in blood may be less likely to reflect total body burden, concentrations in blood of healthy animals may be more biologically relevant and less influenced by state of nutrition or perimortem factors than other tissues routinely sampled. PMID:20966272

  4. Persistent organic pollutants in the blood of free-ranging sea otters (Enhydra lutris ssp.) in Alaska and California

    USGS Publications Warehouse

    Jessup, David A.; Johnson, Christine K.; Estes, James; Carlson-Bremer, Daphne; Jarman, Walter M.; Reese, Stacey; Dodd, Erin; Tinker, M. Tim; Ziccardi, Michael H.

    2010-01-01

    As part of tagging and ecologic research efforts in 1997 and 1998, apparently healthy sea otters of four age-sex classes in six locations in Alaska and three in California were sampled for persistent organic pollutants (POPs) and other chemicals of ecologic or environmental concern (COECs). Published techniques for the detection of POPs (specifically Σpolychlorinated biphenyls [PCBs], ΣDDTs, Σhexachlorocyclohexanes [HCHs], Σpolycyclic aromatic hydrocarbons [PAHs], Σchlordanes [CHLs], hexachlorobenzene [HCB], dieldrin, and mirex) in the tissue of dead otters were modified for use with serum from live sea otters. Toxic equivalencies (TEQs) were calculated for POPs with proven bioactivity. Strong location effects were seen for most POPs and COECs; sea otters in California generally showed higher mean concentrations than those in Alaska. Differences in contaminant concentrations were detected among age and sex classes, with high levels frequently observed in subadults. Very high levels of ΣDDT were detected in male sea otters in Elkhorn Slough, California, where strong freshwater outflow from agricultural areas occurs seasonally. All contaminants except mirex differed among Alaskan locations; only ΣDDT, HCB, and chlorpyrifos differed within California. High levels of ΣPCB (particularly larger, more persistent congeners) were detected at two locations in Alaska where associations between elevated PCBs and military activity have been established, while higher PCB levels were found at all three locations in California where no point source of PCBs has been identified. Although POP and COEC concentrations in blood may be less likely to reflect total body burden, concentrations in blood of healthy animals may be more biologically relevant and less influenced by state of nutrition or perimortem factors than other tissues routinely sampled.

  5. Contamination status and accumulation profiles of organotins in sea otters (Enhydra lutris) found dead along the coasts of California, Washington, Alaska (USA), and Kamchatka (Russia)

    USGS Publications Warehouse

    Murata, S.; Takahashi, S.; Agusa, T.; Thomas, N.J.; Kannan, K.; Tanabe, S.

    2008-01-01

    Organotin compounds (OTs) including mono- to tri-butyltins, -phenyltins, and -octyltins were determined in the liver of adult sea otters (Enhydra lutris) found dead along the coasts of California, Washington, and Alaska in the USA and Kamchatka, Russia. Total concentrations of OTs in sea otters from California ranged from 34 to 4100 ng/g on a wet weight basis. The order of concentrations of OTs in sea otters was total butyltins ??? total octyltins ??? total phenyltins. Elevated concentrations of butyltins (BTs) were found in some otters classified under 'infectious-disease' mortality category. Concentrations of BTs in few of these otters were close to or above the threshold levels for adverse health effects. Total butyltin concentrations decreased significantly in the livers of California sea otters since the 1990s. Based on the concentrations of organotins in sea otters collected from 1992 to 2002, the half-lives of tributyltin and total butyltins in sea otters were estimated to be approximately three years. ?? 2008 Elsevier Ltd. All rights reserved.

  6. Accumulation patterns of heavy metals and chlorinated hydrocarbons by sea otters, Enhydra lutris, in California. Final report

    SciTech Connect

    Risebrough, R.W.

    1989-06-30

    Chemical contaminants and naturally occurring toxic compounds in the coastal ecosystem of California currently inhabited by sea otters, Enhydra lutris, do not appear to have, or have had, any effect on the status of the population. Ratios of pups to adults appear to be within the expected ranges and do not indicate any depressed productivity that might be caused by one or a combination of environmental toxicants. Polychlorinated biphenyls (PCBs), however, which cause nearly complete reproductive failures when fed at levels as low as 0.6 ppm in another member of the family Mustelidae, the mink, Mustela vison, were present in livers of a number of animals at higher levels than those associated with reproductive failure in mink. An interspecific difference in sensitivity, or relatively lower amounts of the more toxic PCB compounds in the sea otter population, is indicated. A decline in PCB (and DDE) levels along the California coast recorded in mussels, Mytilus californianus, and the ending of PCB uses reduce any potential threat to the otter population from PCB contamination.

  7. Sea otter oil spill avoidance study

    SciTech Connect

    Davis, R.W.; Williams, T.M.; Awbrey, F.

    1988-04-01

    To determine whether acoustic, visual, or olfactory stimuli could be used to move sea otters out of an area in the event of an oil spill, the authors recorded the responses of sea otters to a variety of stimuli during captive studies in Alaska. These findings are similar to those of previous attempts to control the movements of sea otters and other marine mammals and birds. An alternative to herding is to capture otters in the vicinity of the spill and temporarily hold them in captivity. This approach is only practical if the number of otters in jeopardy is small (less than 60) and there is enough time to capture them. Based on the results of the study and previous attempts by the California Department of Fish and Game to herd sea otters, the authors do not think acoustic, visual, and olfactory stimuli are effective deterrents. In the absence of effective methods to keep sea otters out of an oil spill, the emphasis must remain on spill prevention, containment, and cleanup.

  8. Comparison of trace element concentrations in livers of diseased, emaciated and non-diseased southern sea otters from the California coast

    USGS Publications Warehouse

    Kannan, K.; Agusa, T.; Perrotta, E.; Thomas, N.J.; Tanabe, S.

    2006-01-01

    Infectious diseases have been implicated as a cause of high rates of adult mortality in southern sea otters. Exposure to environmental contaminants can compromise the immuno-competence of animals, predisposing them to infectious diseases. In addition to organic pollutants, certain trace elements can modulate the immune system in marine mammals. Nevertheless, reports of occurrence of trace elements, including toxic heavy metals, in sea otters are not available. In this study, concentrations of 20 trace elements (V, Cr, Mn, Co, Cu, Zn, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, Pb, and Bi) were measured in livers of southern sea otters found dead along the central California coast (n = 80) from 1992 to 2002. Hepatic concentrations of trace elements were compared among sea otters that died from infectious diseases (n = 27), those that died from non-infectious causes (n = 26), and otters that died in emaciated condition with no evidence of another cause of death (n = 27). Concentrations of essential elements in sea otters varied within an order of magnitude, whereas concentrations of non-essential elements varied by two to five orders of magnitude. Hepatic concentrations of Cu and Cd were 10- to 100-fold higher in the sea otters in this study than concentrations reported for any other marine mammal species. Concentrations of Mn, Co, Zn, and Cd were elevated in the diseased and emaciated sea otters relative to the non-diseased sea otters. Elevated concentrations of essential elements such as Mn, Zn, and Co in the diseased/emaciated sea otters suggest that induction of synthesis of metallothionein and superoxide dismutase (SOD) enzyme is occurring in these animals, as a means of protecting the cells from oxidative stress-related injuries. Trace element profiles in diseased and emaciated sea otters suggest that oxidative stress mediates the perturbation of essential-element concentrations. Elevated concentrations of toxic metals such as Cd, in addition to several

  9. Oral papillomatosis caused by Enhydra lutris papillomavirus 1 (ElPV-1) in southern sea otters (Enhydra lutris nereis) in California, USA.

    PubMed

    Ng, Terry Fei Fan; Miller, Melissa A; Kondov, Nikola O; Dodd, Erin M; Batac, Francesca; Manzer, Mike; Ives, Sarah; Saliki, Jeremiah T; Deng, Xutao; Delwart, Eric

    2015-04-01

    The southern sea otter (Enhydra lutris nereis) is a threatened marine sentinel. During postmortem investigations of stranded sea otters from 2004 to 2013 in California, US, papillomas were detected in the oral cavity of at least seven otters via necropsy and histopathology. Next-generation sequencing of viral particles purified from a single papilloma revealed a novel papillomavirus, Enhydra lutris papillomavirus 1 (ElPV-1). The genome of ElPV-1 was obtained, representing the first fully sequenced viral genome from southern sea otters. Phylogenetic analysis of the entire L1 gene, as well as a concatenated protein identities plot of all papillomaviral genes revealed that ElPV-1 is a λ-papillomavirus, related to a raccoon papillomavirus (Procyon lotor papillomavirus type 1) and a canine oral papillomavirus. Immunohistochemical staining, using a cross-reactive bovine papillomavirus antibody, suggested that ElPV-1 is present in intranuclear inclusions and intracytoplasmic keratin granules. Virus-infected cells were scattered throughout the stratum granulosum and stratum spinosum of the gingival and buccal papillomas. Using ElPV-1-specific PCR, we confirmed viral DNA in oral papillomas from all seven stranded sea otters, with identical L1 sequences. This virus is associated with the development of oral papillomatosis in southern sea otters. PMID:25647597

  10. Accumulation pattern of organochlorine pesticides and polychlorinated biphenyls in sourthern sea otters (Enhydra lutris nereis) found stranded along coastal California, USA

    USGS Publications Warehouse

    Nakata, H.; Kannan, K.; Jing, L.; Thomas, N.J.; Tanabe, S.; Giesy, J.P.

    1998-01-01

    Concentrations of PCBs, DDTs (p,p'-DDE, p,p'-DDD and p,p'-DDT), HCHs (α-, β-, γ-isomers), chlordanes (trans-chlordane, cis-chlordane, trans-nonachlor, cis-nonachlor and oxychlordane) and HCB (hexachlorobenzene were measured in liver, kidney and brain tissues of adult southern sea otters (Enhydra lutris nereis) found stranded along coastal California, USA, during 1992–96. The contamination pattern of organochlorines in sea otters from several locations was in the order of DDTs > PCBs > > CHLs > HCHs > > HCB, whereas those from Monterey Harbor contained greater concentrations of PCBs than of DDTs. Hepatic concentrations of PCBs and DDTs were in the ranges of 58–8700 and 280–5900 ng/g, wet weight, respectively, which varied depending on the geographic location. Sea otters collected from Monterey Harbor contained the greatest concentrations of PCBs and DDTs. In general, accumulation of DDTs, CHLs and PCBs was greater in kidney than in liver, whereas that of HCHs was similar in both the tissues. The gender difference in organochlorine concentrations was less than those reported in cetaceans. The composition of DDTs, HCHs and CHLs compounds in sea otter tissues indicated no recent inputs of these compounds in coastal California. Sea otters that died from infectious diseases, neoplasia and emaciation contained higher concentrations of DDTs than those that died from trauma.

  11. Synopsis of the history of sea otter conservation in the United States

    USGS Publications Warehouse

    Vanblaricom, Glenn R.

    2015-01-01

    In the late 1860s, declining US sea otter populations elicited concern because of prior excessive harvests. Congress mandated protection of Alaskan sea otters in 1868, but hunting continued unrestrained. The Fur Seal Treaty of 1911 (abrogated in 1941) protected sea otters in international waters, but was not applicable to most sea otter habitats and failed to terminate all legal sea otter harvests. Between 1941 and 1972 only the State of California was consistently engaged in sea otter conservation, based on a 1913 state law. Trends in cultural values toward protection of species based on imperiled status rather than economics led to the Marine Mammal Protection Act (1972), giving sea otters unambiguous protection in all US territorial waters. Sea otter habitat protection by the US government began in the 1890s. State marine protected areas potentially support sea otter conservation, particularly when paired with adjacent federal protected entities in or near sea otter habitat.

  12. Novel poxvirus infection in northern and southern sea otters (Enhydra lutris kenyoni and Enhydra lutris neiris), Alaska and California, USA.

    PubMed

    Tuomi, Pamela A; Murray, Michael J; Garner, Michael M; Goertz, Caroline E C; Nordhausen, Robert W; Burek-Huntington, Kathleen A; Getzy, David M; Nielsen, Ole; Archer, Linda L; Maness, Heather T D; Wellehan, James F X; Waltzek, Thomas B

    2014-07-01

    Small superficially ulcerated skin lesions were observed between October 2009 and September 2011 during captive care of two orphaned sea otter pups: one northern (Enhydra lutris kenyoni) in Alaska and one southern (Enhydra lutris nereis) in California. Inclusions consistent with poxviral infection were diagnosed by histopathology in both cases. Virions consistent with poxvirus virions were seen on electron microscopy in the northern sea otter, and the virus was successfully propagated in cell culture. DNA extraction, pan-chordopoxviral PCR amplification, and sequencing of the DNA-dependent DNA polymerase gene revealed that both cases were caused by a novel AT-rich poxvirus. Bayesian and maximum likelihood phylogenetic analyses found that the virus is divergent from other known poxviruses at a level consistent with a novel genus. These cases were self-limiting and did not appear to be associated with systemic illness. To our knowledge, this is the first report of a poxvirus in a mustelid species. The source of this virus, mode of transmission, zoonotic potential, and biological significance are undetermined. PMID:24807180

  13. Studies of the effects of experimentally produced noise associated with oil and gas exploration and development on sea otters in California. Final report

    SciTech Connect

    Riedman, M.L.

    1983-11-15

    During the winter 1983 tape-recorded industrial noises associated with offshore oil and gas operations were projected underwater at Soberanes Point, California. Seismic-exploration sounds were produced using a multiple air gun array (4000 cu. in) and a single air gun (100 cu. in) along a 10-15 km transect paralleling the coastline from Rocky Point to Yankee Point. The behavior, density, and distribution of sea otters (Enhydra lutris) within the vicinity of the sound projection area were not affected by the acoustic experiments. Foraging and diving behaviors of sea otters were normal and undisturbed. There were no movements of otters away from the sound source or out of the sound projection vicinity during either the winter or spring acoustic experiments.

  14. 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.

  15. Sea otter oil-spill mitigation study

    SciTech Connect

    Davis, R.W.; Thomas, J.; Williams, T.M.; Kastelein, R.; Cornell, L.

    1986-05-01

    The objective of the study was to analyze the effectiveness of existing capture, transport, cleaning, and rehabilitation methods and develop new methods to reduce the impact of an accidental oil spill to California sea otters, resulting from the present conditions or from future Outer Continental Shelf (OCS) oil and gas development in State or Federal waters. In addition, the study investigated whether or not a systematic difference in thermal conductivity existed between the pelts of Alaska and California Sea otters. This was done to assure that conclusions drawn from the oiling experiments carried out at Hubbs Marine Research Institute, Tetra Tech, Inc. contributed to the overall study by preparing a literature review and report on the fate and effects of oil dispersants and chemically dispersed oil.

  16. Biological impacts of translocated sea otters. Final report

    SciTech Connect

    Ralls, K.; Siniff, D.B.; Doroff, A.; Mercure, A.

    1990-05-04

    Sea otters are one of the wildlife species most sensitive to oil spills. If an oil spill occurred in the southern part of the sea otter range in California, otters would probably be captured and released in an uncontaminated area to the north. However, if the relocated otters returned to the capture area while oil was still present, they might be contaminated. The main objective of the contract was to learn more about the behavior and movement patterns of sea otters relocated along the central California coast. The authors captured 21 otters and instrumented them with Temple-tag radio transmitters. Using radiotelemetry, we were able to follow the movements of 19 of these otters (18 males and 1 female). They were captured in the southern part of the range near Shell Beach and released about 291 km to the north (as measured on the 5-fathom line) at Moss Landing. None of the 10 otters held in pens for 48 hours prior to release returned to the capture area during the 26 to 89-day monitoring period. Five of the nine otters not held in pens prior to release returned to the capture area 13 to 46 days after release.

  17. 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

  18. 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

  19. 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.

  20. THE HIGH COST OF MOTHERHOOD: END-LACTATION SYNDROME IN SOUTHERN SEA OTTERS (ENHYDRA LUTRIS NEREIS) ON THE CENTRAL CALIFORNIA COAST, USA.

    PubMed

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

    2016-04-28

    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

  1. 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

    ..., 2011 (76 FR 68393), based on a request for a 45-day extension by the California Sea Urchin Commission... continuing, revising, or terminating the southern sea otter translocation program (52 FR 29754, Aug. 11, 1987... southern sea otters (May 8, 1987, 52 FR 17486). Using information obtained over the decades since...

  2. PROTOZOAL MENINGOENCEPHALITIS IN SEA OTTERS (ENHYDRA LUTRIS): A HISTOPATHOLOGICAL AND IMMUNEHISTOCHEMICAL STUDY OF NATURALLY-OCCURRING CASES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Protozoal meningoencephalitis is considered to be an important mortality factor in the California sea otter (Enhydra lutris) population. Of 344 California (CA) and Washington state (WA) sea otters examined from 1985-2004 39 (11.3%) had histopathological evidence of significant protozoal meningoencep...

  3. Sea otter mortality in fish and shellfish traps: Estimating potential impacts and exploring possible solutions

    USGS Publications Warehouse

    Hatfield, B.B.; Ames, J.A.; Estes, J.A.; Tinker, M.T.; Johnson, A.B.; Staedler, M.M.; Harris, M.D.

    2011-01-01

    Sea otters Enhydra lutris can be bycaught and drowned in fishing pots and traps, which may pose a threat to the welfare of otter populations. We explored this potential problem and its solutions using a wide variety of analyses. We exposed live California (USA) sea otters to finfish traps, lobster traps, and mock Dungeness crab traps in captive trials and found that the animals attempted to enter the circular and rectangular fyke openings, with some becoming entrapped. Using both live and dead sea otters, we found that a 3 ?? 9 inch (7.6 ?? 22.9 cm) fyke opening (1 inch narrower than the 4 ?? 9 inch [10.2 ?? 22.9 cm] openings currently used in California's commercial Dungeness crab fishery) would exclude most free-living (i.e. weaned from their mothers) otters while permitting the undiminished capture of crabs. Observer programs do not currently exist in California for these fisheries, so we calculated the effort required by an observer program to document sea otter bycatch over a range of hypothetical levels and evaluated the impact of those mortality rates on population growth. These analyses demonstrate that significant mortality from bycatch might easily go undetected, even with seemingly high levels of observer effort. As sea otters reoccupy portions of their former habitat in California, co-occurrence with finfish and shellfish traps with relatively large fyke openings will increase. ?? Inter-Research 2011.

  4. Clinical pathology and assessment of pathogen exposure in southern and Alaskan sea otters

    USGS Publications Warehouse

    Hanni, K.D.; Mazet, J.A.K.; Gulland, F.M.D.; Estes, James; Staedler, M.; Murray, M.J.; Miller, M.; Jessup, David A.

    2003-01-01

    The southern sea otter (Enhydra lutris nereis) population in California (USA) and the Alaskan sea otter (E. lutris kenyoni) population in the Aleutian Islands (USA) chain have recently declined. In order to evaluate disease as a contributing factor to the declines, health assessments of these two sea otter populations were conducted by evaluating hematologic and/or serum biochemical values and exposure to six marine and terrestrial pathogens using blood collected during ongoing studies from 1995 through 2000. Samples from 72 free-ranging Alaskan, 78 free-ranging southern, and (for pathogen exposure only) 41 debilitated southern sea otters in rehabilitation facilities were evaluated and compared to investigate regional differences. Serum chemistry and hematology values did not indicate a specific disease process as a cause for the declines. Statistically significant differences were found between free-ranging adult southern and Alaskan population mean serum levels of creatinine kinase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, calcium, cholesterol, creatinine, glucose, phosphorous, total bilirubin, blood urea nitrogen, and sodium. These were likely due to varying parasite loads, contaminant exposures, and physiologic or nutrition statuses. No free-ranging sea otters had signs of disease at capture, and prevalences of exposure to calicivirus, Brucella spp., and Leptospira spp. were low. The high prevalence (35%) of antibodies to Toxoplasma gondii in free-ranging southern sea otters, lack of antibodies to this parasite in Alaskan sea otters, and the pathogen's propensity to cause mortality in southern sea otters suggests that this parasite may be important to sea otter population dynamics in California but not in Alaska. The evidence for exposure to pathogens of public health importance (e.g., Leptospira spp., T. gondii) in the southern sea otter population, and the nai??vete?? of both populations to other pathogens (e

  5. Novel Bartonella infection in northern and southern sea otters (Enhydra lutris kenyoni and Enhydra lutris nereis).

    PubMed

    Carrasco, Sebastian E; Chomel, Bruno B; Gill, Verena A; Kasten, Rickie W; Maggi, Ricardo G; Breitschwerdt, Edward B; Byrne, Barbara A; Burek-Huntington, Kathleen A; Miller, Melissa A; Goldstein, Tracey; Mazet, Jonna A K

    2014-06-01

    Since 2002, vegetative valvular endocarditis (VVE), septicemia and meningoencephalitis have contributed to an Unusual Mortality Event (UME) of northern sea otters in southcentral Alaska. Streptococcal organisms were commonly isolated from vegetative lesions and organs from these sea otters. Bartonella infection has also been associated with bacteremia and VVE in terrestrial mammals, but little is known regarding its pathogenic significance in marine mammals. Our study evaluated whether Streptococcus bovis/equinus (SB/E) and Bartonella infections were associated with UME-related disease characterized by VVE and septicemia in Alaskan sea otter carcasses recovered 2004-2008. These bacteria were also evaluated in southern sea otters in California. Streptococcus bovis/equinus were cultured from 45% (23/51) of northern sea otter heart valves, and biochemical testing and sequencing identified these isolates as Streptococcus infantarius subsp. coli. One-third of sea otter hearts were co-infected with Bartonella spp. Our analysis demonstrated that SB/E was strongly associated with UME-related disease in northern sea otters (P<0.001). While Bartonella infection was also detected in 45% (23/51) and 10% (3/30) of heart valves of northern and southern sea otters examined, respectively, it was not associated with disease. Phylogenetic analysis of the Bartonella ITS region allowed detection of two Bartonella species, one novel species closely related to Bartonella spp. JM-1, B. washoensis and Candidatus B. volans and another molecularly identical to B. henselae. Our findings help to elucidate the role of pathogens in northern sea otter mortalities during this UME and suggested that Bartonella spp. is common in sea otters from Alaska and California. PMID:24629902

  6. Genetic diversity among sea otter isolates of Toxoplasma gondii

    USGS Publications Warehouse

    Sundar, N.; Cole, R.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 gondii and at times succumb to clinical disease. Here, we determined genotypes of 39 T. gondii isolates 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.

  7. Association between perfluorinated compounds and pathological conditions in southern sea otters

    USGS Publications Warehouse

    Kannan, K.; Perrotta, E.; Thomas, N.J.

    2006-01-01

    Concentrations of four perfluorinated contaminants, including perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), were measured in liver tissue from 80 adult female sea otters collected from the California coast during 1992a??2002. Concentrations of PFOS and PFOA were in the ranges of <1a??884 and <5a??147 ng/g, wet wt, respectively. Concentrations of PFOA in the livers of these sea otters were among the highest values reported for marine mammals to date. Liver tissue from 6 male sea otters also was analyzed and contained significantly higher concentrations of PFOS than did tissues from female otters. To examine the association between exposures and potential effects, concentrations of PFOS and PFOA were compared among the adult female otters that died from infectious diseases, noninfectious causes, and from apparent emaciation. Concentrations of both PFOA and PFOS were significantly higher in sea otters in the infectious disease category than in the noninfectious category. Concentrations of PFOS and PFOA were not significantly different between noninfectious and emaciated otters, suggesting that the poor nutritive (body) status of emaciated otters did not affect the concentrations of perfluorochemicals in livers. Concentrations of PFOA increased significantly from 1992 to 2002, whereas PFOS concentrations increased from 1992 to 1998 and then decreased after 2000. Significant association between infectious diseases and elevated concentrations of PFOS/PFOA in the livers of sea otters is a cause for concern and suggests the need for further studies.

  8. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff.

    PubMed

    Miller, Melissa A; Byrne, Barbara A; Jang, Spencer S; Dodd, Erin M; Dorfmeier, Elene; Harris, Michael D; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A; Miller, Woutrina A

    2010-01-01

    Although protected for nearly a century, California's sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health. PMID:19720009

  9. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff

    PubMed Central

    Miller, Melissa A.; Byrne, Barbara A.; Jang, Spencer S.; Dodd, Erin M.; Dorfmeier, Elene; Harris, Michael D.; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A.; Miller, Woutrina A.

    2009-01-01

    Although protected for nearly a century, California’s sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health. PMID:19720009

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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, ...

  11. Histopathologic lesions in sea otters exposed to crude oil.

    PubMed

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

  12. Histopathologic lesions in sea otters exposed to crude oil

    SciTech Connect

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

    1993-01-01

    On 24 March 1989, the oil tanker Exxon Valdez ran aground on Bligh Reef in Prince William Sound, Alaska. In the months following the spill, over 1,000 sea otters (Enhydra lutris) from oil spill-affected areas are known to have died. The purpose of the study is to identify and describe histopathologic lesions associated with crude oil exposure in sea otters and to discuss possible pathogeneses of the lesions. Materials available included tissues from oil-contaminated and uncontaminated otters that died in rehabilitation centers following the oil spill and tissues from otters that were found dead in the oil spill-affected area with external oil present. Tissues from apparently normal sea otters from an area not contaminated by crude oil, were also examined.

  13. Population model for Alaska Peninsula sea otters. Final report

    SciTech Connect

    Eberhardt, L.L.; Siniff, D.B.

    1988-12-31

    This study was conducted to provide a basis for assessing risks of oil spills to sea otter populations along the Alaska Peninsula. The principal efforts were devoted to analyzing the available data on population dynamics. Curves characterizing survivorship and reproduction for sea otters were devised and fitted to several data sets. A detailed review was conducted of methods of assessing population dynamics data, and several new techniques (e.g., bootstrapping) were applied to available data. A simplified model for use with Alaska Peninsula sea otter populations was devised and implemented in a 'spreadsheet' format. Various aspects of model development and data on population size in Alaska Peninsula areas were reviewed.

  14. 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.

  15. Variation in delta13C and delta15N diet-vibrissae trophic discrimination factors in a wild population of California sea otters.

    PubMed

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

    2010-09-01

    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 delta(c-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 delta13C and delta15N 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 per thousand +/- 0.7 per thousand for delta13C and 3.5 per thousand +/- 0.6 per thousand for delta15N (mean +/- SD) were similar to those reported for captive carnivores, and variation in individual delta13C 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. PMID:20945772

  16. 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.

  17. Coastal freshwater runoff is a risk factor for Toxoplasma gondii infection of southern sea otters (Enhydra lutris nereis).

    PubMed

    Miller, M A; Gardner, I A; Kreuder, C; Paradies, D M; Worcester, K R; Jessup, D A; Dodd, E; Harris, M D; Ames, J A; Packham, A E; Conrad, P A

    2002-07-01

    The association among anthropogenic environmental disturbance, pathogen pollution and the emergence of infectious diseases in wildlife has been postulated, but not always well supported by epidemiologic data. Specific evidence of coastal contamination of the marine ecosystem with the zoonotic protozoan parasite, Toxoplasma gondii, and extensive infection of southern sea otters (Enhydra lutris nereis) along the California coast was documented by this study. To investigate the extent of exposure and factors contributing to the apparent emergence of T. gondii in southern sea otters, we compiled environmental, demographic and serological data from 223 live and dead sea otters examined between 1997 and 2001. The T. gondii seroprevalence was 42% (49/116) for live otters, and 62% (66/107) for dead otters. Demographic and environmental data were examined for associations with T. gondii seropositivity, with the ultimate goal of identifying spatial clusters and demographic and environmental risk factors for T. gondii infection. Spatial analysis revealed clusters of T. gondii-seropositive sea otters at two locations along the coast, and one site with lower than expected T. gondii seroprevalence. Risk factors that were positively associated with T. gondii seropositivity in logistic regression analysis included male gender, older age and otters sampled from the Morro Bay region of California. Most importantly, otters sampled near areas of maximal freshwater runoff were approximately three times more likely to be seropositive to T. gondii than otters sampled in areas of low flow. No association was found between seropositivity to T. gondii and human population density or exposure to sewage. This study provides evidence implicating land-based surface runoff as a source of T. gondii infection for marine mammals, specifically sea otters, and provides a convincing illustration of pathogen pollution in the marine ecosystem. PMID:12076629

  18. Coxiella burnetii exposure in northern sea otters Enhydra lutris kenyoni.

    PubMed

    Duncan, Colleen; Gill, Verena A; Worman, Kristin; Burek-Huntington, Kathy; Pabilonia, Kristy L; Johnson, Sam; Fitzpatrick, Kelly A; Weller, Christina; Kersh, Gilbert J

    2015-05-11

    Valvular endocarditis has been well described in northern sea otters Enhydra lutris kenyoni of Alaska and in many cases no cause has been identified. It is also one of the most common conditions observed in people with chronic Coxiella burnetii infection. Given the high levels of C. burnetii exposure in marine mammals distributed throughout the same geographic range as the northern sea otter, and the presence of valvular lesions seen in otters, the objective of this study was to determine the level of C. burnetii exposure in otters and investigate any association between exposure, infection and valvular disease in this species. Archived serum from 75 live captured, apparently healthy otters (25 from each of 3 stocks) and 30 dead otters were tested for C. burnetii antibodies by indirect florescent antibody assay (IFA). Archived bone marrow and heart valves were tested for C. burnetii DNA by real-time PCR (qPCR). Overall, the seroprevalence in live otters was 17%, with significantly more exposed animals in the south central (40%) stock relative to the southwest (8%) and southeast (4%). The seroprevalence of animals sampled post mortem was 27%, although none of the bone marrow or heart valve samples were positive by qPCR. Results of this study failed to demonstrate a significant association between C. burnetii infection and valvular endocarditis in sea otters; however, the differing seroprevalence suggests that exposure opportunities vary geographically. PMID:25958809

  19. The risk of disease and threats to the wild population. Special Issue: Conservation and Management of the Southern Sea Otter

    USGS Publications Warehouse

    Thomas, N.J.; Cole, R.A.

    1996-01-01

    The growth of the southern sea otter population has been steady, but slow in comparison to Alaskan subspecies, and range expansion in California has faltered. Slower growth is occurring in California despite birth rates comparable to those in Alaska, so biologists have reasoned that mortality is hindering the growth of the California population (Riedman and Estes 1990; see Estes et al., this issue). In order to investigate this issue, research efforts have been directed toward identifying the causes of death in southern sea otters.

  20. Genetic diversity and population parameters of sea otters, Enhydra lutris, before fur trade extirpation from 1741-1911.

    PubMed

    Larson, Shawn; Jameson, Ron; Etnier, Michael; Jones, Terry; Hall, Roberta

    2012-01-01

    All existing sea otter, Enhydra lutris, populations have suffered at least one historic population bottleneck stemming from the fur trade extirpations of the eighteenth and nineteenth centuries. We examined genetic variation, gene flow, and population structure at five microsatellite loci in samples from five pre-fur trade populations throughout the sea otter's historical range: California, Oregon, Washington, Alaska, and Russia. We then compared those values to genetic diversity and population structure found within five modern sea otter populations throughout their current range: California, Prince William Sound, Amchitka Island, Southeast Alaska and Washington. We found twice the genetic diversity in the pre-fur trade populations when compared to modern sea otters, a level of diversity that was similar to levels that are found in other mammal populations that have not experienced population bottlenecks. Even with the significant loss in genetic diversity modern sea otters have retained historical structure. There was greater gene flow before extirpation than that found among modern sea otter populations but the difference was not statistically significant. The most dramatic effect of pre fur trade population extirpation was the loss of genetic diversity. For long term conservation of these populations increasing gene flow and the maintenance of remnant genetic diversity should be encouraged. PMID:22403635

  1. Genetic Diversity and Population Parameters of Sea Otters, Enhydra lutris, before Fur Trade Extirpation from 1741–1911

    PubMed Central

    Larson, Shawn; Jameson, Ron; Etnier, Michael; Jones, Terry; Hall, Roberta

    2012-01-01

    All existing sea otter, Enhydra lutris, populations have suffered at least one historic population bottleneck stemming from the fur trade extirpations of the eighteenth and nineteenth centuries. We examined genetic variation, gene flow, and population structure at five microsatellite loci in samples from five pre-fur trade populations throughout the sea otter's historical range: California, Oregon, Washington, Alaska, and Russia. We then compared those values to genetic diversity and population structure found within five modern sea otter populations throughout their current range: California, Prince William Sound, Amchitka Island, Southeast Alaska and Washington. We found twice the genetic diversity in the pre-fur trade populations when compared to modern sea otters, a level of diversity that was similar to levels that are found in other mammal populations that have not experienced population bottlenecks. Even with the significant loss in genetic diversity modern sea otters have retained historical structure. There was greater gene flow before extirpation than that found among modern sea otter populations but the difference was not statistically significant. The most dramatic effect of pre fur trade population extirpation was the loss of genetic diversity. For long term conservation of these populations increasing gene flow and the maintenance of remnant genetic diversity should be encouraged. PMID:22403635

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

    USGS Publications Warehouse

    Bowen, L.; Aldridge, B.M.; Miles, A.K.; 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. ?? 2006 Blackwell Munksgaard.

  3. 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.

  4. 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.

  5. 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.

  6. 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. PMID:27070027

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

    USGS Publications Warehouse

    Aguilar, A.; Jessup, David A.; Estes, James; 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 200years), but a Bayesian method found a signal of a strong reduction over a longer time scale (up to 500years 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. ?? Journal compilation ?? 2007 The Zoological Society of London No claim to original US government works.

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

    USGS Publications Warehouse

    Fujii, Jessica A; 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.

  9. Protozoal Meningoencephalitis in Sea Otters (Enhydra lutris): a Histopathological and Immunohistochemical Study of Naturally Occuring Cases

    USGS Publications Warehouse

    Thomas, N.J.; Dubey, J.P.; Lindsay, D.S.; Cole, R.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. neurona meningoencephalitis, multifocal to diffuse gliosis was widespread in grey matter and consistently present in the molecular layer of the cerebellum. In T. gondii meningoencephalitis, 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.

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

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

    PubMed

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

    2009-02-17

    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

  1. 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.

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

    PubMed

    Rodriguez-Ramos Fernandez, J; 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 sea otters. 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. PMID:22520807

  3. HISTOPATHOLOGIC LESIONS IN SEA OTTERS EXPOSED TO CRUDE OIL

    EPA Science Inventory

    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. xposure t...

  4. Genetic diversity among sea otter isolates of Toxoplasma gondii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sea otters (Enhydra lutris) have been reported to become infected with Toxoplasma gondii and at times succumb to clinical disease. The mode of marine contamination has been the subject of recent papers. Because of their susceptibility these animals can serve as a sentinel for contamination of marine...

  5. Serum vitamin A concentrations in captive sea otters (Enhydra lutris).

    PubMed

    Righton, Alison L; St Leger, Judy A; Schmitt, Todd; Murray, Michael J; Adams, Lance; Fascetti, Andrea J

    2011-03-01

    Individual dietary preferences and difficulty with animal training create challenges and nutritional concerns when evaluating a captive sea otter (Enhydra lutris) diet. The importance of vitamin A within the body reflects the necessity that it be ingested in adequate amounts to ensure optimal health. To compare levels of serum vitamin A concentrations from captive sea otters on daily oral vitamin A supplementation, serum samples from eight adult sea otters from three institutions were evaluated for serum vitamin A concentrations. The eight animals were fed a total of four different diets and received oral supplementation via three different methods. Multiple diet items were analyzed for vitamin A content and were found to have low to nondetectable levels of vitamin A. Oral vitamin A supplementation, as a slurry with dietary items, was shown to be effective and a mean serum concentration of approximately 170 +/- 51 microg/L was obtained for serum vitamin A concentrations in captive sea otters. Captive diets can be modified to increase vitamin A concentration and supplementation and, if accepted, can be used as a means to ensure adequate vitamin A intake. PMID:22946382

  6. 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.

  7. 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; 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.

  8. 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.

  9. Sea otter studies in Glacier Bay National Park and Preserve

    USGS Publications Warehouse

    Bodkin, J.L.; Kloecker, K.A.; Esslinger, G.G.; Monson, D.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

  10. Are sea otters being exposed to subsurface intertidal oil residues from the Exxon Valdez oil spill?

    PubMed

    Boehm, P D; Page, D S; Neff, J M; Brown, J S

    2011-03-01

    Twenty years after the Exxon Valdez oil spill, scattered patches of subsurface oil residues (SSOR) can still be found in intertidal sediments at a small number of shoreline locations in Prince William Sound, Alaska. Some scientists hypothesize that sea otters continue to be exposed to SSOR by direct contact when otters dig pits in search of clams. This hypothesis is examined through site-specific examinations where SSOR and otter-dug pits co-occur. Surveys documented the exact sediment characteristics and locations on the shore at the only three subdivisions where both SSOR and otter pits were found after 2000. Shoreline characteristics and tidal heights where SSOR have persisted are not suitable habitat for sea otters to dig pits during foraging. There is clear separation between areas containing SSOR and otter foraging pits. The evidence allows us to reject the hypothesis that sea otters encounter and are being exposed by direct contact to SSOR. PMID:21185036

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

    USGS Publications Warehouse

    Johnson, Christine K.; Tinker, M.T.; Estes, J.A.; Conrad, P.A.; Staedler, M.; Miller, M.A.; Jessup, David A.; Mazet, J.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. ?? 2009 by The National Academy of Sciences of the USA.

  12. Verification of sex from harvested sea otters using DNA testing

    USGS Publications Warehouse

    Scribner, K.T.; Green, B.A.; Gorbics, C.; Bodkin, J.

    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.

  13. Stock structure of sea otters (Enhydra Lutris Kenyoni) in Alaska

    USGS Publications Warehouse

    Gorbics, C.S.; Bodkin, J.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.

  14. SARCOCYSTS OF AN UNIDENTIFIED SPECIES OF SARCOCYSTIS IN SEA OTTER (ENHYDRA LUTRIS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The number of Sarcocystis species that infect sea otters (Enhydra lutris) is unknown. Sea otter tissues were recently shown to harbor sarcocysts of Sarcocystis neurona and of unidentified species of Sarcocystis. Whereas sarcocysts of S. neurona have walls 1-3 µm thick with Type 9 villar protrusion...

  15. 78 FR 34652 - Proposed Information Collection; Comment Request; Reporting Requirements for Sea Otter...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... 30, 2007, NMFS published a final rule (72 FR 29891) implementing a requirement under the CPS FMP to report any interactions that may occur between a CPS vessel and/or fishing gear and sea otters... Requirements for Sea Otter Interactions With the Pacific Sardine Fishery; Coastal Pelagic Species...

  16. An aerial survey method to estimate sea otter abundance

    USGS Publications Warehouse

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

    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.

  17. Stable lead isotopes evidence anthropogenic contamination in Alaskan sea otters

    SciTech Connect

    Smith, D.R.; Estes, J.A.; Flegal, A.R. ); Niemeyer, S. )

    1990-10-01

    Lead concentrations and stable isotopic compositions were measured in teeth of preindustrial and contemporary sea otters (Enhydra lutris) from Amchitka Island, AK, to determine if changes had occurred in the magnitude and source of assimilated lead. Although there was no significant difference in lead concentrations between the two groups of otters ({bar x} {plus minus} {sigma}Pb/Ca atomic = 3.6 {plus minus} 2.9 {times} 10{sup {minus}8}), differences in stable lead isotopic compositions revealed a pronounced change in the source of accumulated lead. Lead {bar x} {plus minus} 2{sigma}{sub {bar x}} in the preindustrial otters ({sup 207}Pb/{sup 206}Pb = 0.828 {plus minus} 0.006) was derived from natural deposits in the Aleutian arc, while lead in the contemporary animals ({sup 207}Pb/{sup 206}Pb = 0.856 {plus minus} 0.003) was primarily industrial lead from Asia and western Canada. The isotopic ratios demonstrate anthropogenic perturbations of the lead cycle in present-day coastal food webs and indicate that lead concentration measurements alone are inadequate in assessing the introduction and transport of contaminant lead in the environment.

  18. 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.

  19. 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.

  20. Adaptation to hard-object feeding in sea otters and hominins.

    PubMed

    Constantino, Paul J; Lee, James J-W; Morris, Dylan; Lucas, Peter W; Hartstone-Rose, Adam; Lee, Wah-Keat; Dominy, Nathaniel J; Cunningham, Andrew; Wagner, Mark; Lawn, Brian R

    2011-07-01

    The large, bunodont postcanine teeth in living sea otters (Enhydra lutris) have been likened to those of certain fossil hominins, particularly the 'robust' australopiths (genus Paranthropus). We examine this evolutionary convergence by conducting fracture experiments on extracted molar teeth of sea otters and modern humans (Homo sapiens) to determine how load-bearing capacity relates to tooth morphology and enamel material properties. In situ optical microscopy and x-ray imaging during simulated occlusal loading reveal the nature of the fracture patterns. Explicit fracture relations are used to analyze the data and to extrapolate the results from humans to earlier hominins. It is shown that the molar teeth of sea otters have considerably thinner enamel than those of humans, making sea otter molars more susceptible to certain kinds of fractures. At the same time, the base diameter of sea otter first molars is larger, diminishing the fracture susceptibility in a compensatory manner. We also conduct nanoindentation tests to map out elastic modulus and hardness of sea otter and human molars through a section thickness, and microindentation tests to measure toughness. We find that while sea otter enamel is just as stiff elastically as human enamel, it is a little softer and tougher. The role of these material factors in the capacity of dentition to resist fracture and deformation is considered. From such comparisons, we argue that early hominin species like Paranthropus most likely consumed hard food objects with substantially higher biting forces than those exerted by modern humans. PMID:21474163

  1. 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. PMID:21782345

  2. 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.

  3. 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.

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

    PubMed

    Anthony, Robert G; Estes, James A; Ricca, Mark A; Miles, A Keith; Forsman, Eric D

    2008-10-01

    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

  5. 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

  6. Mustelid herpesvirus-2, a novel herpes infection in northern sea otters (Enhydra lutris kenyoni).

    PubMed

    Tseng, Marion; Fleetwood, Michelle; Reed, Aimee; Gill, Verena A; Harris, R Keith; Moeller, Robert B; Lipscomb, Thomas P; Mazet, Jonna A K; Goldstein, Tracey

    2012-01-01

    Oral ulcerations and plaques with epithelial eosinophilic intranuclear inclusions were observed in northern sea otters (Enhydra lutris kenyoni) that died or were admitted for rehabilitation after the 1989 Exxon Valdez oil spill (EVOS) in Alaska, USA. Transmission electron microscopy demonstrated the presence of herpesviral virions. Additionally, a serologic study from 2004 to 2005 found a high prevalence of exposure to a herpesvirus in live-captured otters. Tissues from 29 otters after the EVOS and nasal swabs from 83 live-captured otters in the Kodiak Archipelago were tested for herpesviral DNA. Analysis identified a novel herpesvirus in the gamma subfamily, most closely related to Mustelid herpesvirus-1 from badgers. Results indicated that this herpesvirus is associated with ulcerative lesions but is also commonly found in secretions of healthy northern sea otters. PMID:22247388

  7. 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

  8. Sea otter abundance in Kenai Fjords national Park: results from the 2010 aerial survey

    USGS Publications Warehouse

    Coletti, Heather A.; Bodkin, James L.; Esslinger, George

    2011-01-01

    Fjord, Nuka Bay and Nuka Island. All observed otters were in the high density stratum, defined as the 0 m to 40 m depth contour and minimum distances from shore, while no sea otters were observed in the low density stratum, which is defined as the area within the 40m to 100 m depth contour. We recommend that prior to the next aerial sea otter survey in KEFJ (scheduled for 2013), a power simulation be conducted to evaluate methods to improve precision of estimates and the ability to detect change.

  9. An intersection model for estimating sea otter mortality along the Kenai Peninsula

    USGS Publications Warehouse

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

    1994-01-01

    We developed an intersection model to integrate parameters estimated from three distinct data sets that resulted from the Exxon Valdez oil spill: (1) the distribution, amount, and movements of spilled oil; (2) the distribution and abundance of sea otters along the Kenai Peninsula; and (3) the estimates of site-specific sea otter mortality relative to oil exposure from otters captured for rehabilitation and from collected carcasses. In this chapter, we describe the data sets and provide examples of how they can be used in the model to generate acute loss estimates. We also examine the assumptions required for the model and provide suggestions for improving and applying the model.

  10. The dental pathology of southern sea otters (Enhydra lutris nereis).

    PubMed

    Winer, J N; Liong, S M; Verstraete, F J M

    2013-01-01

    Skulls (n = 1,205) of southern sea otters were examined macroscopically according to defined criteria. The museum specimens, acquired from strandings, varied in age from juvenile to adult, with an equal sex distribution. The results from all young adult and adult specimens were pooled according to tooth type. Ninety-two percent of teeth were available for examination, with 6.5% artifactually absent, 0.6% deemed absent due to acquired tooth loss and 0.03% deemed congenitally absent. All teeth were normal in morphology, except for three pairs of fused teeth, including two instances of fused maxillary first incisor teeth. Supernumerary teeth were associated with 97 normal teeth (most commonly maxillary canine teeth) in 68 specimens. At least one persistent deciduous tooth was present in six skulls, two of which were from adults. The majority (94.6%) of alveoli, either with or without teeth, were not associated with bony changes consistent with periodontitis; however, the majority (74.4%) of specimens did have at least one tooth associated with mild periodontitis. The mesial root of the mandibular third premolar tooth was the most common location at which periodontal hard tissue lesions were observed (56.6%). Ten sea otters had lesions consistent with focal enamel hypoplasia. Approximately half of the teeth (52.0%) were abraded; almost all adult specimens (98.1%) contained at least one abraded tooth, while fewer young adults were affected (76.4%). Tooth fractures were uncommon, affecting 1,343 teeth (4.5%). Periapical lesions were associated with 409 teeth (1.3%) in a total of 176 specimens, and these would likely have caused considerable morbidity while the animals were alive. PMID:23348015

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

    PubMed

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

    2010-06-01

    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. PMID:20132952

  12. Sea Otters Homogenize Mussel Beds and Reduce Habitat Provisioning in a Rocky Intertidal Ecosystem

    PubMed Central

    Singh, Gerald G.; Markel, Russell W.; Martone, Rebecca G.; Salomon, Anne K.; Harley, Christopher D. G.; Chan, Kai M. A.

    2013-01-01

    Sea otters (Enhydra lutris) are keystone predators that consume a variety of benthic invertebrates, including the intertidal mussel, Mytilus californianus. By virtue of their competitive dominance, large size, and longevity, M. californianus are ecosystem engineers that form structurally complex beds that provide habitat for diverse invertebrate communities. We investigated whether otters affect mussel bed characteristics (i.e. mussel length distributions, mussel bed depth, and biomass) and associated community structure (i.e. biomass, alpha and beta diversity) by comparing four regions that varied in their histories of sea otter occupancy on the west coast of British Columbia and northern Washington. Mussel bed depth and average mussel lengths were 1.5 times lower in regions occupied by otters for >20 years than those occupied for <5 yrs. Diversity of mussel bed associated communities did not differ between regions; however, the total biomass of species associated with mussel beds was more than three-times higher where sea otters were absent. We examined alternative explanations for differences in mussel bed community structure, including among-region variation in oceanographic conditions and abundance of the predatory sea star Pisaster ochraceus. We cannot discount multiple drivers shaping mussel beds, but our findings indicate the sea otters are an important one. We conclude that, similar to their effects on subtidal benthic invertebrates, sea otters reduce the size distributions of intertidal mussels and, thereby, habitat available to support associated communities. Our study indicates that by reducing populations of habitat-providing intertidal mussels, sea otters may have substantial indirect effects on associated communities. PMID:23717697

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

    USGS Publications Warehouse

    Bodkin, J.L.; Ballachey, B.E.; Dean, T.A.; Fukuyama, A.K.; Jewett, S.C.; McDonald, L.; Monson, D.H.; O'Clair, C. 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

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

    USGS Publications Warehouse

    Bodkin, J.L.; Ballachey, B.E.; Dean, T.A.; Fukuyama, A.K.; Jewett, S.C.; McDonald, L.; Monson, D.H.; O'Clair, C. 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

  15. 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

  16. Innervation patterns of sea otter (Enhydra lutris) mystacial follicle-sinus complexes.

    PubMed

    Marshall, Christopher D; Rozas, Kelly; Kot, Brian; Gill, Verena A

    2014-01-01

    Sea otters (Enhydra lutris) are the most recent group of mammals to return to the sea, and may exemplify divergent somatosensory tactile systems among mammals. Therefore, we quantified the mystacial vibrissal array of sea otters and histologically processed follicle-sinus complexes (F - SCs) to test the hypotheses that the number of myelinated axons per F - SC is greater than that found for terrestrial mammalian vibrissae and that their organization and microstructure converge with those of pinniped vibrissae. A mean of 120.5 vibrissae were arranged rostrally on a broad, blunt muzzle in 7-8 rows and 9-13 columns. The F-SCs of sea otters are tripartite in their organization and similar in microstructure to pinnipeds rather than terrestrial species. Each F-SC was innervated by a mean 1339 ± 408.3 axons. Innervation to the entire mystacial vibrissal array was estimated at 161,313 axons. Our data support the hypothesis that the disproportionate expansion of the coronal gyrus in somatosensory cortex of sea otters is related to the high innervation investment of the mystacial vibrissal array, and that quantifying innervation investment is a good proxy for tactile sensitivity. We predict that the tactile performance of sea otter mystacial vibrissae is comparable to that of harbor seals, sea lions and walruses. PMID:25400554

  17. 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. PMID:25249386

  18. Innervation patterns of sea otter (Enhydra lutris) mystacial follicle-sinus complexes

    PubMed Central

    Marshall, Christopher D.; Rozas, Kelly; Kot, Brian; Gill, Verena A.

    2014-01-01

    Sea otters (Enhydra lutris) are the most recent group of mammals to return to the sea, and may exemplify divergent somatosensory tactile systems among mammals. Therefore, we quantified the mystacial vibrissal array of sea otters and histologically processed follicle-sinus complexes (F - SCs) to test the hypotheses that the number of myelinated axons per F - SC is greater than that found for terrestrial mammalian vibrissae and that their organization and microstructure converge with those of pinniped vibrissae. A mean of 120.5 vibrissae were arranged rostrally on a broad, blunt muzzle in 7–8 rows and 9–13 columns. The F-SCs of sea otters are tripartite in their organization and similar in microstructure to pinnipeds rather than terrestrial species. Each F-SC was innervated by a mean 1339 ± 408.3 axons. Innervation to the entire mystacial vibrissal array was estimated at 161,313 axons. Our data support the hypothesis that the disproportionate expansion of the coronal gyrus in somatosensory cortex of sea otters is related to the high innervation investment of the mystacial vibrissal array, and that quantifying innervation investment is a good proxy for tactile sensitivity. We predict that the tactile performance of sea otter mystacial vibrissae is comparable to that of harbor seals, sea lions and walruses. PMID:25400554

  19. 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, T.A.; Bodkin, J.L.; Jewett, S.C.; Monson, D.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.

  20. Modified-closed castration: a novel technique for sea otter (Enhydra lutris nereis) orchiectomies.

    PubMed

    McDermott, Alexa J; Clauss, Tonya; Sakals, Sherisse; Mejia, Johanna; Radlinsky, MaryAnn G

    2013-09-01

    A novel surgical technique was used in the routine castrations of two intact male southern sea otters, Enhydra lutris nereis, housed at the Georgia Aquarium (Atlanta, Georgia, USA). This technique involved incising the parietal vaginal tunic to allow placement of double ligation of the ductus deferens, testicular artery, and pampiniform plexus en masse. After ligating and transecting these structures, they were introduced back into the tunic, which was closed with a circumferential ligature. The incision site was closed in a routine manner. Both otters recovered well from the procedure. One otter had mild cutaneous dehiscence postoperatively, and the other had no obvious complications. Benefits of this procedure include reduced risk of ligature slippage or loosening and resultant hemorrhage, as provided by the traditional open portion of the castration, and decreased postoperative swelling, as provided by the closed part of the castration. To the authors' knowledge, this is the first time this technique has been described for use in sea otters. PMID:24063115

  1. Characterization of the Temporomandibular Joint of Southern Sea Otters (Enhydra lutris nereis).

    PubMed

    Lieske, Danielle; Vapniarsky, Natalia; Verstraete, Frank J M; Leale, Dustin M; Young, Colleen; Arzi, Boaz

    2015-01-01

    The structure-function relationship of the temporomandibular joint (TMJ) of southern sea otter has largely not been described. This study aims to describe the histological, biochemical, and biomechanical features of the TMJ disk in the southern sea otter. The TMJ disks from fresh cadaver heads of southern sea otter adult males (n = 8) and females (n = 8) acquired from strandings were examined. Following macroscopical evaluation, the TMJs were investigated for their histological, mechanical, and biochemical properties. We found that the sea otter TMJ disks are, in general, similar to other carnivores. Macroscopically, the TMJ disk was highly congruent, and the mandibular head was encased tightly by the mandibular fossa with a thin disk separating the joint into two compartments. Histologically, the articular surfaces were lined with dense fibrous connective tissue that gradually transitioned into one to two cell thick layer of hyaline-like cartilage. The disk fibers were aligned primarily in the rostrocaudal direction and had occasional lacuna with chondrocyte-like cells. The disk was composed primarily of collagen type 1. Biochemical analysis indicates sulfated glycosaminoglycan content lower than other mammals, but significantly higher in male sea otters than female sea otters. Finally, mechanical analysis demonstrated a disk that was not only stronger and stiffer in the rostrocaudal direction than the mediolateral direction but also significantly stronger and stiffer in females than males. We conclude that the congruent design of the TMJ, thin disk, biochemical content, and mechanical properties all reflect a structure-function relationship within the TMJ disk that is likely designed for the sea otter's hard diet and continuous food intake. PMID:26664997

  2. Diving and foraging energetics of the smallest marine mammal, the sea otter (Enhydra lutris).

    PubMed

    Yeates, Laura C; Williams, Terrie M; Fink, Traci L

    2007-06-01

    As the smallest and one of the most recently evolved marine mammals, sea otters face physiological challenges rarely encountered by larger, more derived aquatic species. To examine the effect of these challenges on foraging costs and resultant daily energy budgets, we measured the energetics of resting, grooming, diving and foraging for adult, male sea otters. The energy expended for these different behaviors as determined from open flow respirometry was then standardized across activity budgets measured for wild sea otters to estimate field metabolic rates (FMR). We found that the metabolic rate of captive otters performing single dives ranging in duration from 40 to 192 s was 17.6+/-0.5 ml O(2) kg(-1) min(-1) and only 1.3 times resting rates. This rate increased significantly if the animals foraged during submergence. The cost of a foraging dive for sea otters was nearly twice that predicted for phocid seals, which was attributed in part to elevated locomotor costs associated with buoyancy and swimming style. Our behavioral studies indicate that wild sea otters spend the greatest proportion of the day feeding and resting, with the largest daily energy expenditure (6.1+/-1.1 MJ day(-1)) associated with foraging. The resulting mean FMR for wild sea otters based on the energy expended for all behaviors was 15.7+/-2.7 MJ day(-1) and matched predicted FMR values based upon a regression of known FMR values for other marine mammals across a range of body sizes. This was achieved by counterbalancing elevated foraging costs with prolonged periods of rest on the water surface. PMID:17515421

  3. 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. PMID:26504217

  4. 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

  5. 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. PMID:17969707

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

    USGS Publications Warehouse

    Ballachey, B.E.; Bodkin, J.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.

  7. Foraging depths of sea otters and implications to coastal marine communities

    USGS Publications Warehouse

    Bodkin, J.L.; Esslinger, G.G.; Monson, D.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.

  8. Characterization of the Temporomandibular Joint of Southern Sea Otters (Enhydra lutris nereis)

    PubMed Central

    Lieske, Danielle; Vapniarsky, Natalia; Verstraete, Frank J. M.; Leale, Dustin M.; Young, Colleen; Arzi, Boaz

    2015-01-01

    The structure–function relationship of the temporomandibular joint (TMJ) of southern sea otter has largely not been described. This study aims to describe the histological, biochemical, and biomechanical features of the TMJ disk in the southern sea otter. The TMJ disks from fresh cadaver heads of southern sea otter adult males (n = 8) and females (n = 8) acquired from strandings were examined. Following macroscopical evaluation, the TMJs were investigated for their histological, mechanical, and biochemical properties. We found that the sea otter TMJ disks are, in general, similar to other carnivores. Macroscopically, the TMJ disk was highly congruent, and the mandibular head was encased tightly by the mandibular fossa with a thin disk separating the joint into two compartments. Histologically, the articular surfaces were lined with dense fibrous connective tissue that gradually transitioned into one to two cell thick layer of hyaline-like cartilage. The disk fibers were aligned primarily in the rostrocaudal direction and had occasional lacuna with chondrocyte-like cells. The disk was composed primarily of collagen type 1. Biochemical analysis indicates sulfated glycosaminoglycan content lower than other mammals, but significantly higher in male sea otters than female sea otters. Finally, mechanical analysis demonstrated a disk that was not only stronger and stiffer in the rostrocaudal direction than the mediolateral direction but also significantly stronger and stiffer in females than males. We conclude that the congruent design of the TMJ, thin disk, biochemical content, and mechanical properties all reflect a structure–function relationship within the TMJ disk that is likely designed for the sea otter’s hard diet and continuous food intake. PMID:26664997

  9. 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. PMID:26610978

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

    USGS Publications Warehouse

    Monson, D.H.; McCormick, C.; Ballachey, B.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.

  11. 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. PMID:26494610

  12. Locally acquired disseminated histoplasmosis in a northern sea otter (Enhydra lutris kenyoni) in Alaska, USA.

    PubMed

    Burek-Huntington, Kathy A; Gill, Verena; Bradway, Daniel S

    2014-04-01

    Histoplasmosis of local origin has not been reported in humans or wildlife in Alaska, and the disease has never been reported in a free-ranging marine mammal. In 2005 a northern sea otter (Enhydra lutris kenyoni) was found on Kodiak Island, Alaska, at 57° latitude north, far outside the known distribution of Histoplasma capsulatum. The animal died of disseminated histoplasmosis. Microorganisms consistent with Histoplasma sp. were observed on histopathology, and H. capsulatum was identified by PCR and sequencing. We suggest migratory seabirds or aerosol transmission through prevailing winds may have resulted in transmission to the sea otter. PMID:24484503

  13. Indirect effects of sea otters on rockfish (Sebastes spp.) in giant kelp forests.

    PubMed

    Markel, Russell W; Shurin, Jonathan B

    2015-11-01

    Sea otters are a classic example of a predator controlling ecosystem productivity through cascading effects on basal, habitat-forming kelp species. However, their indirect effects on other kelp-associated taxa like fishes are poorly understood. We examined the effects of sea otter (Enhydra lutris) reintroduction along the west coast of Vancouver Island, Canada on giant kelp (Macrocystis pyrifera) distributions and the trophic niches and growth of two common kelp forest fishes, black (Sebastes melanops) and copper (S. caurinus) rockfishes. We sampled 47 kelp forests, and found that red sea urchins (Strongylocentrotus franciscanus) were eliminated in the presence of otters, and that kelp forests were 3.7 times deeper and 18.8 times larger. Despite order-of-magnitude differences in kelp forest size, adult black and copper rockfishes contained less kelp-derived carbon in their tissues (as measured by stable isotopes of C and N) in regions with otters. Adults of both species had higher mean trophic positions in the presence of otters, indicating more frequent consumption of higher trophic level prey such as fishes. Smaller trophic niche space of rockfishes in the presence of otters indicated a higher degree of trophic specialization. Juvenile black rockfishes rapidly shifted to higher kelp-carbon contents, trophic positions, and body condition factors after settling in kelp forests. The relationships of growth to length, percentage of kelp carbon, and trophic position varied between the two regions, indicating that potential effects of kelp forest size on trophic ontogeny may also affect individual performance. Our results provide evidence that the indirect effects of otters on rockfishes arise largely through the creation of habitat for fishes and other prey rather than a direct trophic connection through invertebrates or other consumers of kelp productivity. PMID:27070008

  14. 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).

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

    PubMed

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

    2014-06-15

    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). PMID:24920834

  16. 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

  17. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. 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.

  20. 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

    ... public on November 9, 2012 (77 FR 67302; 77 FR 67362). This Federal Register document records our..., 2012 (77 FR 67302; 77 FR 67362), which evaluates options for continuing, revising, or terminating the... population of removing individual southern sea otters for ] translocation (52 FR 29754; August 11, 1987)....

  1. 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

    ... reduced range, and the potential risk from oil spills (42 FR 2965). We established a recovery team for the... which sea otters would be excluded (51 FR 29362). Concurrently, we released a draft environmental impact... (52 FR 17486). A detailed translocation plan meeting the requirements of Public Law 99-625...

  2. 75 FR 11115 - Proposed Information Collection; Comment Request; Reporting Requirements for Sea Otter...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-10

    ... (USFWS) regarding the possible effects of implementing Amendment 11 (71 FR 36999) to the Coastal Pelagic... of the species. Therefore on May 30, 2007, NMFS published a final rule (72 FR 29891) implementing new... Requirements for Sea Otter Interactions with the Pacific Sardine Fishery; Coastal Pelagic Species...

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

    USGS Publications Warehouse

    Bodkin, J.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 potentially moderating the effects of prey reductions on the female population. Increased adult male mortality at Bearing Island in 1990-1991 likely modified the sex and age class structure there toward that observed in Prince William Sound.

  4. 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

    ...We, the U.S. Fish and Wildlife Service (Service), published a proposed rule and notice of availability of a revised draft supplemental environmental impact statement on the translocation of southern sea otters (revised draft SEIS) in the Federal Register on August 26, 2011. The U.S. Environmental Protection Agency concurrently published a notice of availability of the revised draft SEIS. The......

  5. Refractive state, ocular anatomy, and accommodative range of the sea otter (Enhydra lutris).

    PubMed

    Murphy, C J; Bellhorn, R W; Williams, T; Burns, M S; Schaeffel, F; Howland, H C

    1990-01-01

    Sea otters are carnivorous, amphibious mammals that are active both above and under water. Accordingly, it might be expected that their eyes are adapted for both aerial and aqueous vision. We examined the anatomy and physiological optics of the sea otter eye with a view towards describing and explaining its amphibious visual characteristics. We employed photokeratoscopy to measure the refractive power of the sea otter cornea, which we found to be 59 D. Using video dynamic photorefraction, we found that sea otters can focus targets clearly both in air and water, relying on accommodation to compensate for the refractive loss of their corneas upon immersion in water. Our anatomical investigations revealed that the anterior epithelium of the cornea is extensively developed, as is the iris musculature, meridional ciliary muscle, and the corneoscleral venous plexus. The first feature is most likely an adaptation to the salinity of the marine environment. We believe the latter features are part of a novel, well-developed lenticular accommodative mechanism. PMID:2321364

  6. 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

  7. 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).

  8. Preliminary findings of fecal gonadal hormone concentrations in six captive sea otters (Enhydra lutris) after deslorelin implantation.

    PubMed

    Larson, S; Belting, T; Rifenbury, K; Fisher, G; Boutelle, S M

    2013-01-01

    The sea otter (Enhydra lutris) is a popular exhibit animal in many zoos and aquariums worldwide. Captive sea otters from these populations are owned by the United States Fish and Wildlife Service (USFWS). The USFWS has requested that these sea otters be prevented from breeding in order to save captive space for wild rescued animals. Sea otters are often housed in mixed sex groups, therefore a chemical contraceptive method or surgical removal of gonads must be used to prevent potential pregnancy. The contraceptive, Suprelorin® or deslorelin, has been used in many different species to effectively suppress reproduction but duration of effect may vary not only between species but also individuals. Here, we report the effects of one to several consecutive deslorelin implants on gonadal reproductive hormones found in fecal samples from six captive sea otters (two males and four females) compared to two control otters (one male and one female) housed at three zoological institutions. We documented the longitudinal hormone signatures of many stages of the contraceptive cycle including pretreatment (PT), stimulatory phase (S), effective contraception (EC), and hormone reversal (HR) that was characterized by a return to normal hormone levels. Deslorelin was found to be an effective contraceptive in sea otters and was found to be reversible documented by a live birth following treatment, however the duration of suppression in females was much longer than expected with a 6-month and a 1-year implant lasting between 3 and 4 years in females. PMID:22753108

  9. PREVALENCE, PATHOLOGY, AND RISK FACTORS ASSOCIATED WITH STREPTOCOCCUS PHOCAE INFECTION IN SOUTHERN SEA OTTERS (ENHYDRA LUTRIS NEREIS), 2004-10.

    PubMed

    Bartlett, Georgina; Smith, Woutrina; Dominik, Clare; Batac, Francesca; Dodd, Erin; Byrne, Barbara A; Jang, Spencer; Jessup, David; Chantrey, Julian; Miller, Melissa

    2016-01-01

    Recent studies have implicated beta-hemolytic streptococci as opportunistic pathogens of marine mammals, including southern sea otters (Enhydra lutris nereis), but little is known about their prevalence or pathophysiology. Herein, we focus on risk factors for sea otter infection by a single beta-hemolytic streptococcal species, Streptococcus phocae. Streptococcus phocae was first identified as a marine mammal pathogen in 1994, and the first report in southern sea otters was in 2009. Its broad host range encompasses fish, pinnipeds, cetaceans, and mustelids, with S. phocae now recognized as an important pathogen of marine species worldwide. We assessed risk factors and lesion patterns for S. phocae infection in southern sea otters. Using archival necropsy data, S. phocae prevalence was 40.5% in fresh dead otters examined 2004-10. Skin trauma of any type was identified as a significant risk factor for S. phocae infection. The risk of infection was similar regardless of the cause and relative severity of skin trauma, including mating or fight wounds, shark bite, and anthropogenic trauma. Streptococcus phocae-infected sea otters were also more likely to present with abscesses or bacterial septicemia. Our findings highlight the importance of S. phocae as an opportunistic pathogen of sea otters and suggest that the most likely portal of entry is damaged skin. Even tiny skin breaks appear to facilitate bacterial colonization, invasion, abscess formation, and systemic spread. Our data provide important insights for management and care of marine species. PMID:26555115

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

    SciTech Connect

    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 Prince 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.

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

    USGS Publications Warehouse

    Cronin, M.A.; Bodkin, J.L.; Ballachey, B.E.; Estes, J.A.; Patton, J.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 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. l. lutris and E. l. 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.

  12. 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).

  13. 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.

  14. 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

  15. 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. PMID:20615616

  16. 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.

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

    PubMed

    Harwell, Mark A; Gentile, John H

    2014-06-01

    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

  18. 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

  19. 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.

  20. The high cost of reproduction in sea otters necessitates unique physiological adaptations.

    PubMed

    Thometz, Nicole M; Kendall, Traci L; Richter, Beau P; Williams, Terrie M

    2016-08-01

    Superimposed on inherently high basal metabolic demands, the additional energetic requirements of reproduction can push female sea otters beyond physiological limits. Indeed, the resulting energy imbalance contributes to disproportionately high rates of mortality at the end of lactation in this species. To examine and quantify metabolic changes associated with reproduction, we measured the resting metabolic rate (RMR) of a female sea otter across gestation, lactation and non-reproductive periods. Concurrently, measurements were made on a non-breeding control female. Our results suggest that RMR declines during gestation. Conversely, RMR increases during lactation, reaches a peak at 3-4 months postpartum, and remains elevated until weaning. Combining these direct measurements with published data, we found the cost of pup rearing to be significantly higher than previously estimated. High baseline energy demands and limited energy reserves, combined with significant lactation and pup rearing costs, appear to necessitate metabolic and thermal lability during key reproductive stages. PMID:27489214

  1. Ontogenetic Scaling of Theoretical Bite Force in Southern Sea Otters (Enhydra lutris nereis).

    PubMed

    Law, Chris J; Young, Colleen; Mehta, Rita S

    2016-01-01

    Sexual dimorphism attributed to niche divergence is often linked to differentiation between the sexes in both dietary resources and characters related to feeding and resource procurement. Although recent studies have indicated that southern sea otters (Enhydra lutris nereis) exhibit differences in dietary preferences as well as sexual dimorphism in skull size and shape, whether these intersexual differences translate to differentiation in feeding performances between the sexes remains to be investigated. To test the hypothesis that scaling patterns of bite force, a metric of feeding performance, differ between the sexes, we calculated theoretical bite forces for 55 naturally deceased male and female southern sea otters spanning the size ranges encountered over ontogeny. We then used standardized major axis regressions to simultaneously determine the scaling patterns of theoretical bite forces and skull components across ontogeny and assess whether these scaling patterns differed between the sexes. We found that positive allometric increases in theoretical bite force resulted from positive allometric increases in physiological cross-sectional area for the major jaw adductor muscle and mechanical advantage. Closer examination revealed that allometric increases in temporalis muscle mass and relative allometric decreases in out-lever lengths are driving these patterns. In our analysis of sexual dimorphism, we found that scaling patterns of theoretical bite force and morphological traits do not differ between the sexes. However, adult sea otters differed in their absolute bite forces, revealing that adult males exhibited greater bite forces as a result of their larger sizes. We found intersexual differences in biting ability that provide some support for the niche divergence hypothesis. Continued work in this field may link intersexual differences in feeding functional morphology with foraging ecology to show how niche divergence has the potential to reinforce sexual

  2. 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; Bodkin, James; 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

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

    USGS Publications Warehouse

    Larson, S.; Monson, D.; Ballachey, B.; Jameson, R.; 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. ?? 2009 by the Society for Marine Mammalogy.

  4. 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.

  5. 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; 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.

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

    PubMed

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

    2015-05-01

    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. PMID:25645269

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

    PubMed

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

    1995-07-01

    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. PMID:7483208

  8. 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, J.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. ?? 2002 Elsevier Science Ltd. All rights reserved.

  9. 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, J.L.; Kelly, J.J.

    2003-01-01

    Marine mammals being in the top predator 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 1950's was significantly higher than those collected in the 1990's. 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.

  10. 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.

  11. 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. PMID:16572322

  12. Sea otter (Enhydra lutris) perspective: Mechanisms of impact and potential recovery of nearshore vertebrate predators following the 1989 Exxon Valdez oil spill. Part A. Sea otter population status and the process of recovery from the 1989 Exxon Valdez oil spill

    USGS Publications Warehouse

    Bodkin, J.L.; Ballachey, B.E.; Dean, T.A.; Fukuyama, A.K.; Jewett, S.C.; McDonald, L.; Monson, D.H.; O'Clair, C. E.; VanBlaricom, G.R.

    2002-01-01

    Sea otter (Enhydra lutris populations were severely affects 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 approached 0.90, no increase has been observed. Sea otter reproduction was not impaired and the age and sex structure of animals captured are consistent with both intrinsic reproduction and immigration contributing to recovery. However, low resighting rates of marked animals at Knight Island compared to an unoiled reference area, and a high proportion of young animals 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, in 1996-98 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, as 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

  13. 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).

  14. 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, J.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.

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

    USGS Publications Warehouse

    Monson, D.H.; Doak, D.F.; Ballachey, B.E.; Bodkin, J.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

  16. 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

  17. 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. PMID:25319817

  18. 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, B.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

  19. Histopathologic lesions associated with crude oil exposure in sea otters. Marine mammal study 6-10. Exxon Valdez oil spill state/federal natural resources damage assessment final report

    SciTech Connect

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

    1996-06-01

    Following the Exxon Valdez oil spill in Prince William Sound, Alaska, sea otters (Enhydra lutris) that appeared oiled, were in danger of becoming oiled, or were behaving abnormally were captured and taken to rehabilitation centers. Oil exposure was assessed by visual examination on arrival at the centers. Tissues from 51 oiled sea otters and from 6 unoiled sea otters that died in rehabilitation centers were examined histologically. Histologic examinations were performed on tissues from 5 sea otters found dead with external oil present shortly after the spill. Necropsies were performed on 214 sea otters that had been collected and frozen in the period following the oil spill. Tissues from 6 apparently normal sea otters collected from an area not affected by the oil spill were examined histologically, and none of these lesions were found. We conclude that pulmonary interstitial emphysema, gastric erosion and hemorrhage, centrilobular hepatic necrosis, and hepatic and renal lipidosis were associated with exposure to crude oil in sea otters.

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

    USGS Publications Warehouse

    Bodkin, J.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.

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

    USGS Publications Warehouse

    Goldstein, T.; Gill, V.A.; Tuomi, P.; Monson, D.; Burdin, A.; Conrad, P.A.; Dunn, J.L.; Field, C.; Johnson, Chad; Jessup, David A.; Bodkin, J.; Doroff, A.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 Toxoplasmagondii, 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 nai{dotless}??ve and susceptible marine mammal populations, tissues should be examined to explore the contribution of this virusto otter deaths. Our results reveal an increase in exposure to pathogens in sea otters in Kodiak,Alaska, USA, since the 1990s. ?? Wildlife Disease Association 2011.

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

    PubMed

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

    2011-07-01

    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 1990 s. PMID:21719822

  3. 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

  4. 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). 

  5. Ganglion cells density and retinal resolution in the sea otter, Enhydra lutris.

    PubMed

    Mass, A M; Supin, A Y

    2000-03-01

    The topographic distribution, density, and size of ganglion cells were studied in retinal wholemounts of the sea otter, Enhydra lutris. The cell distribution showed a well defined horizontal streak of higher cell density, and within this streak, a narrow area of the highest cell density. The peak cell density in this area ranged from 4050 to 4400 cells/mm(2), with a mean of 4225 cells/mm(2). The ganglion cell size ranged from 7 microm to 47 microm but the majority of cells were 7 to 30 microm. Cell size distribution revealed three size groups: 7-16, 17-28, and 29-47 microm. The highest-density area contained mainly small (7-16 microm) cells. The cell-density data predict a retinal resolution around 7' in water. Retinal organization in the sea otter exhibits more properties common with terrestrial rather than aquatic mammals, both in terms of ganglion cell characteristics and in terms of their topographic distribution. PMID:10899706

  6. Pathogenesis of Streptococcus infantarius subspecies coli Isolated from Sea Otters with Infective Endocarditis.

    PubMed

    Counihan, Katrina L; Gill, Verena A; Miller, Melissa A; Burek-Huntington, Kathleen A; LeFebvre, Rance B; Byrne, Barbara A

    2015-06-01

    The Gram positive bacterial coccus Streptococcus infantarius subspecies coli is increasingly linked with development of fatal vegetative infective endocarditis and septicemia in humans, sea otters (Enhydra lutris) and other animals. However, the pathogenesis of these infections is poorly understood. Using S. infantarius subsp. coli strains isolated from sea otters with infective endocarditis, this study evaluated adherence and invasion of epithelial and endothelial cells, adherence to extracellular matrix components, and macrophage survival. Significant adherence to endothelial-derived cells was observed for 62% of isolates, 24% adhered to epithelial cell lines, and 95% invaded one or both cell types in vitro. The importance of the hyaluronic acid capsule in host cell adherence and invasion was also evaluated. Capsule removal significantly reduced epithelial adherence and invasion for most S. infantarius subsp. coli isolates, suggesting that the capsule facilitates attachment to and invasion of epithelium. Enzyme-linked immunosorbent assay testing revealed that all isolates adhered significantly to the extracellular matrix components collagen IV, fibronectin, laminin and hyaluronic acid. Finally, significant bacterial survival following phagocytosis by macrophages was apparent for 81% of isolates at one or more time points. Taken collectively these findings indicate that S. infantarius subsp. coli has multiple pathogenic properties that may be important to host colonization, invasion and disease. PMID:25838157

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

    USGS Publications Warehouse

    Tinker, M.T.; Doak, D.F.; Estes, J.A.; Hatfield, B.B.; Staedler, M.M.; Bodkin, J.L.

    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.

  8. Osteoarthritis of the temporomandibular joint in southern sea otters (Enhydra lutris nereis).

    PubMed

    Arzi, B; Winer, J N; Kass, P H; Verstraete, F J M

    2013-11-01

    Museum skull specimens (n = 1,008) of southern sea otters (Enhydra lutris nereis) were examined macroscopically according to defined criteria for the presence, severity and characteristics of temporomandibular joint osteoarthritis (TMJ-OA). The specimens were from stranded young adult to adult animals. Overall, 4.1% of the specimens had findings consistent with TMJ-OA. Of these, 61.0% were from females and 39.0% were from males. In addition, 85.4% of the affected specimens were from adults and 14.6% were from young adults. However, there was no significant association between age and sex with the presence or severity of TMJ-OA. Lesion severity was mild in 41.5%, moderate in 19.5% and severe in 39.0% of affected specimens. The most prominent changes were the presence of osteophytes and subchondral bone defects and porosity. The mandibular condylar process and fossa were affected equally. The lengths of the right and left mandibular heads were significantly associated with age (P = 0.002 and P = 0.003, respectively) and sex (P = 0.0009 and P = 0.001, respectively), but not with the presence of TMJ-OA. The significance of this disease in sea otters remains elusive, but this condition may play an important role in survival of these animals. PMID:23721871

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

    PubMed

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

    2013-10-01

    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). PMID:24502716

  10. 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. PMID:22740531

  11. Pathological studies of sea otters. Marine mammal study 6-11. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Lipscomb, T.P.; Harris, R.K.; Rebar, A.H.; Ballachey, B.E.; Haebler, R.J.

    1996-06-01

    Following the Exxon Valdez oil spill, sea otters were captured and taken to rehabilitaion centers. Oil exposure was assessed by visual examination on arrival at the centers. Records of 21 oiled otters that died within 10 days of arrival at the centers were reviewed to define the laboratory abnormalities and clinical syndromes associated with these deaths. Tissues from 51 oiled and 6 unoiled sea otters that died in the centers were examined histologically. Histologic examinations were performed on tissues from 5 oiled otters found dead shortly after the spill. Nucropsies were performed on 214 sea otters that were collected and frozen following the oil spill. Pulmonary interstitial emphysema and gastric erosion and hemorrhage were common in oiled animals, and were less frequent in unoiled animals. Tissues from 6 sea otters collected from a nonoiled area were examined, and none of these lesions were found. We conclude that pulmonary interstitial emphysema, gastric erosion and hemorrhage, centrilobular hepatic necrosis, and hepatic and renal lipidosis were associated with exposure to crude oil in sea otters.

  12. A unique feeding strategy of the extinct marine mammal Kolponomos: convergence on sabretooths and sea otters.

    PubMed

    Tseng, Z Jack; Grohé, Camille; Flynn, John J

    2016-03-16

    Mammalian molluscivores feed mainly by shell-crushing or suction-feeding. The extinct marine arctoid, Kolponomos, has been interpreted as an otter-like shell-crusher based on similar dentitions. However, neither the masticatory biomechanics of the shell-crushing adaptation nor the way Kolponomos may have captured hard-shelled prey have been tested. Based on mandibular symphyseal morphology shared by Kolponomos and sabre-toothed carnivores, we hypothesize a sabretooth-like mechanism for Kolponomos prey-capture, whereby the mandible functioned as an anchor. Torque generated from jaw closure and head flexion was used to dislodge prey by prying, with prey then crushed using cheek teeth. We test this hypothesized feeding sequence using phylogenetically informed biomechanical simulations and shape analyses, and find a strongly supported, shared high mandibular stiffness in simulated prey-capture bites and mandibular shape in Kolponomos and the sabre-toothed cat Smilodon. These two distantly related taxa converged on using mandibles to anchor cranial torqueing forces when prying substrate-bound prey in the former and sabre-driving forces during prey-killing in the latter. Simulated prey-crushing bites indicate that Kolponomos and sea otters exhibit alternative structural stiffness-bite efficiency combinations in mandibular biomechanical adaptation for shell-crushing. This unique feeding system of Kolponomos exemplifies a mosaic of form-function convergence relative to other Carnivora. PMID:26936242

  13. Population model for sea otters in western Prince William sound. Restoration project 93043-3. Sea otter demographics. Exxon Valdez oil spill restoration project final report

    SciTech Connect

    Udevitz, M.S.; Ballachey, B.E.; Bruden, D.L.

    1996-05-01

    A large portion of the western Prince William Sound (PWS) sea otter population was killed by the Exxon Valdez oil spill in March 1989, but little is known about the dynamics of the population before the spill in March 1989, or the rate at which the population can be expected to recover. We estimated age-specific reproductive and survival rates for the western PWS population before the spill based on examinations or reproductive tracts and the age structure of carcasses collected in 1989. We developed a new technique for estimating survival rates that uses age-structure and age-at-death data, and does not require the assumption of a stable age structure. Because of the lack of data for estimating juvenile survival rates, were considered a series of 4 potential scenarios. The population was projected to decrease slightly during the first year under all of the scenarios and then begin increasing, achieving maximum rates of increase ranging from 10% to 14% per year and recovering to its estimated 1985 population size in 10 to 23 years. Projected population sizes during the first few years after the spill are in broad agreement with estimates based on boat surveys in 1990, 1991, and 1993.

  14. Sea otter abundance, distribution, and pup production in Prince William Sound following the Exxon Valdez oil spill

    SciTech Connect

    Johnson, C.B.; Garshelis, D.L.

    1995-12-31

    The authors investigated effects of the 1989 Exxon Valdez oil spill on the abundance, distribution, and pup production of sea otters (Enhydra lutris) in prince William Sound (PWS) by comparing counts made during 1990 and 1991 with counts made by researchers 5--12 years before the spill. The authors observed no evidence of avoidance or attraction to spill-affected shorelines 1--2 years after the spill. Despite a substantial loss of sea otters immediately following the spill, the authors counted fewer otters than prespill investigators at only one of three heavily oiled islands, and from 1990 to 1991 the counts at this one site increased to a level equivalent to the latest (1985) prespill count. The authors followed the methods of prespill investigators and found close agreement between the counts of otters and those of two other concurrent investigations using the same survey technique. This agreement among counts, and the involvement in counts made prespill, suggested that inter-observer variability could not explain the unexpected high counts at oiled sites. 52 refs., 18 figs., 5 tabs.

  15. 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

  16. 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

  17. Ontogeny of Oxygen Storage Capacity and Diving Ability in the Southern Sea Otter (Enhydra lutris nereis): Costs and Benefits of Large Lungs.

    PubMed

    Thometz, Nicole M; Murray, Michael J; Williams, Terrie M

    2015-01-01

    Small body size, large lungs, and dense pelage contribute to the unique challenges faced by diving sea otters (Enhydra lutris) when compared to other marine mammals. Here we determine the consequences of large lungs on the development of diving ability in southern sea otters (Enhydra lutris nereis) by examining the ontogeny of blood, muscle, and lung oxygen stores and calculating aerobic dive limits (cADL) for immature and mature age classes. Total oxygen storage capacity matures rapidly in sea otters, reaching adult levels by 2 mo postpartum. But this result is driven by exceptional lung capacity at birth, followed by a decrease in mass-specific lung volume with age. Blood and muscle oxygen stores remain well below adult values before weaning, with large pups exhibiting 74% and 54% of adult values, respectively. Slow muscle development limits the capacity of immature sea otters to dive against high positive buoyancy due to comparatively large lungs. Immature sea otters diving with total lung capacity (TLC) experience up to twice the mass-specific positive buoyancy as adults diving with TLC but can reduce these forces to comparable adult levels by using a smaller diving lung volume (DLV). The cADL of a juvenile with DLV is 3.62 min, while the cADL of an adult with TLC is 4.82 min. We find that the magnitude of positive buoyancy experienced by sea otters changes markedly with age and strongly influences the ontogeny of diving ability in this species. PMID:25860829

  18. 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. PMID:18761099

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

    SciTech Connect

    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. 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.

  20. 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. PMID:23639486

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

    USGS Publications Warehouse

    Bowen, L.; Riva, F.; Mohr, C.; Aldridge, B.; Schwartz, J.; Miles, A.K.; 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. ?? 2007 Ecohealth Journal Consortium.

  2. 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, J.; Monson, D.; Schneider, K.

    2006-01-01

    3In 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.4Body 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.5Population 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).6This 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.

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

    USGS Publications Warehouse

    Bodkin, J.; Mulcahy, D.; Lensink, C.

    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 oit 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 wre similiar to those reported in the literature based on in situ observations of marked individuals.

  4. Age distributions of sea otters found dead in Prince William Sound, Alaska, following the Exxon Valdez oil spill. Marine mammal study 6-15. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Monson, D.H.; Ballachey, B.

    1995-06-01

    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 recovered in 1990-1991 may be evidence of a prolonged, spill-related effect on the western Prince William Sound sea otter population.

  5. Long-term impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality patterns.

    PubMed

    Monson, D H; Doak, D F; Ballachey, B E; Johnson, A; Bodkin, J L

    2000-06-01

    We use age distributions of sea otters (Enhydra lutris) found dead on beaches of western Prince William Sound, Alaska, between 1976 and 1998 in conjunction with time-varying demographic models to test for lingering effects from the 1989 Exxon Valdez oil spill. Our results show that sea otters in this area had decreased survival rates in the years following the spill and that the effects of the spill on annual survival increased rather than dissipated for older animals. Otters born after the 1989 spill were affected less than those alive in March 1989, but do show continuing negative effects through 1998. Population-wide effects of the spill appear to have slowly dissipated through time, due largely to the loss of cohorts alive during the spill. Our results demonstrate that the difficult-to-detect long-term impacts of environmental disasters may still be highly significant and can be rigorously analyzed by using a combination of population data, modeling techniques, and statistical analyses. PMID:10823920

  6. 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. PMID:25715875

  7. Long-term impacts of the Exxon Valdez oil spill on sea otters, assessed through age-dependent mortality patterns

    USGS Publications Warehouse

    Monson, D.H.; Doak, D.F.; Ballachey, B.E.; Johnson, Aaron H.; Bodkin, J.L.

    2000-01-01

    We use age distributions of sea otters (Enhydra lutris) found dead on beaches of western Prince William Sound, Alaska, between 1976 and 1998 in conjunction with time-varying demographic models to test for lingering effects from the 1989 Exxon Valdez oil spill. Our results show that sea otters in this area had decreased survival rates in the years following the spill and that the effects of the spill on annual survival increased rather than dissipated for older animals. Otters born after the 1989 spill were affected less than those alive in March 1989, but do show continuing negative effects through 1998. Population-wide effects of the spill appear to have slowly dissipated through time, due largely to the loss of cohorts alive during the spill. Our results demonstrate that the difficult-to-detect long- term impacts of environmental disasters may still be highly significant and can be rigorously analyzed by using a combination of population data, modeling techniques, and statistical analyses.

  8. 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

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

    USGS Publications Warehouse

    Bodkin, J.L.; Kloecker, K.A.; Esslinger, G.G.; Monson, D.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

  10. 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.

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

    USGS Publications Warehouse

    Bodkin, J.L.; Ballachey, B.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.

  12. 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.

  13. Sound production and reception in southern sea otters (Enhydra lutris nereis).

    PubMed

    Ghoul, Asila; Reichmuth, Colleen

    2012-01-01

    Because of their dependence on a highly restricted coastal habitat, Enhydra lutris is especially vulnerable to a variety of different environmental and anthropogenic threats. This species is presently listed as threatened and is protected throughout the northern and southern portions of its range.Resource managers are presently faced with uncertainty when responding to and prioritizing potential threats to these animals due to insufficient understanding of the factors that may disturb or disrupt normal behavior patterns both above and below the water's surface. The objective of these studies was to obtain direct measurements of the source characteristics of vocalizations and the limits of auditory reception in Enhydra lutris. These data are necessary to form a basic but essential under-standing of bioacoustics in this species. To further develop this knowledge base, psychoacoustic profiles of aerial and underwater hearing sensitivity as a function of sound frequency are imperative to adequately consider sea otters alongside other marine mammals within the issue of anthropogenic impacts. These studies are presently ongoing i n our laboratory. A s these coastal-living carnivores have only recently transitioned to a marine lifestyle, an improved understanding of their acoustic communication and auditory adaptations will also provide insight into their evolutionary biology and behavioral ecology as well as the evolutionary pressures shaping underwater perception in marine mammals. PMID:22278472

  14. Mortality and reproduction of female sea otters in Prince William Sound, Alaska. Marine mammal study 6-13. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Monnett, C.; Rotterman, L.M.

    1995-05-01

    Ninety-six female sea otters were instrumeted with implanted radio-transmitters in Prince William Sound, Alaska, during 1989-1990. Females in eastern Prince William Sound exhibited a lower survival rate than those in western Prince William Sound. No differences were observed between rates of pupping or between rates of survival of dependent pups for sea otters in the two areas.

  15. Intersection model for estimating sea otter mortality from the Exxon Valdez oil spill along the Kenai Peninsula, Alaska. Marine mammal study 6-5. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

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

    1995-06-01

    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 of 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.

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

    USGS Publications Warehouse

    Tinker Tim, M.; Guimarães, Paulo R., Jr.; 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.

  17. 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; Kloecker, Kim; 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.

  18. 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 A.; 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.

  19. Organochloride pesticides in California sea lions revisited

    PubMed Central

    Le Boeuf, Burney J; Giesy, John P; Kannan, Kurunthachalam; Kajiwara, Natsuko; Tanabe, Shinsuke; Debier, Cathy

    2002-01-01

    Background Dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that have been banned in most countries, but considerable amounts continue to cycle the ecosphere. Top trophic level predators, like sea birds and marine mammals, bioaccumulate these lipophilic compounds, reflecting their presence in the environment. Results We measured concentrations of tDDT (p,p' - DDT + p,p' - DDD + p,p' - DDE) and PCBs in the blubber of dead California sea lions stranded along the California coast. tDDT and PCB concentrations were 150 ± 257 ug/g lipid weight (mean ± SD) and 44 ± 78 ug/g lipid weight, respectively. There were no differences in tDDT or PCB concentrations between animal categories varying in sex or age. There was a trend towards a decrease in tDDT and PCB concentrations from northern to southern California. The lipid content of the blubber was negatively correlated with levels of tDDT and PCBs. tDDT concentrations were approximately 3 times higher than PCB concentrations. Conclusions tDDT levels in the blubber of California sea lions decreased by over one order of magnitude from 1970 to 2000. PCB level changes over time were unclear owing to a paucity of data and analytical differences over the years. Current levels of these pollutants in California sea lions are among the highest among marine mammals and exceed those reported to cause immunotoxicity or endocrine disruption. PMID:12479795

  20. Biogeochemistry of the Salton Sea, California

    NASA Astrophysics Data System (ADS)

    Amrhein, C.; Reese, B. K.; Anderson, M. A.

    2006-12-01

    The Salton Sea is a saline, closed basin lake 70 meters below MSL in the southern desert of California. It is the largest lake in California with a surface area of 945 km2 and an annual inflow of 1,600 million m3. The Sea is hypereutrophic due to nutrient inputs from farm runoff, and anaerobic conditions in the bottom water result in summer and fall releases of hydrogen sulfide and fish kills. The salinity of the Sea is 47 g/L and rising, with an annual salt load of 4 million metric tons. Plans are being developed for construction of a salt repository to control salinization, improve water quality, and maintain the Sea as a refuge for migratory waterfowl. We estimate 700,000 metric tons of calcite are precipitating in the Sea each year, along with 7,000 tons of iron sulfide minerals. Potentially, 70,000 metric tons of hydrogen sulfide are produced in the Sea each year. Measurements of hydrogen sulfide production, reoxidation in the water column, and atmospheric releases will be reported. Hydrodynamic modeling of the current Sea, and the proposed smaller Sea, indicate that partitioning the Sea could lead to persistent stratification and episodic releases of hydrogen sulfide during fall mixing.

  1. 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.

  2. SeaWiFS: California Coastal Blooms

    NASA Technical Reports Server (NTRS)

    2002-01-01

    There was a good bit of variety in the water colors off the California coast on September 3, 2001. This SeaWiFS image shows various phytoplankton blooms that paint the water green, aquamarine, and even rust colored in places.

  3. Technical report: Marine mammals study number 6. Mortality and reproduction of sea otters oiled and treated as a result of the Exxon Valdez oil spill. Marine mammal study 6-14. Exxon Valdez oil spill state/federal natural resource damage assessment final report. Technical report

    SciTech Connect

    Monnett, C.; Rotterman, L.M.

    1995-05-01

    Radio-instrumented sea otters (N = 45) that were released into eastern Prince William Sound during summer, 1989, following efforts to rehabilitate them at otter treatment centers, have been monitored regularly for approximately 2 years. Respective survival rates of male and female sea otters released from the treatment centers were: Year 1: males P = 0,401, females P = 0.401, females P = 0.445; Year 2: males P = 0.714, females P = 0.692. Only 2 of 11 (18%) mature females pupped during 1990. Sea otters released from treatment centers had lower survivorship and pupping rates than sea otters in other study populations.

  4. 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). PMID:25588007

  5. Permissible Home Range Estimation (PHRE) in Restricted Habitats: A New Algorithm and an Evaluation for Sea Otters

    PubMed Central

    Tarjan, L. Max; 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. PMID:27003710

  6. Permissible Home Range Estimation (PHRE) in Restricted Habitats: A New Algorithm and an Evaluation for Sea Otters.

    PubMed

    Tarjan, L Max; 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. PMID:27003710

  7. 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.

  8. 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. PMID:25416538

  9. 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. PMID:21298711

  10. 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

    SciTech Connect

    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 of 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.

  11. Imperial Valley and Salton Sea, California

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Southern California's Salton Sea is a prominent visual for astronauts. This large lake supports the rich agricultural fields of the Imperial, Coachella and Mexicali Valleys in the California and Mexico desert. The Salton Sea formed by accident in 1905 when an irrigation canal ruptured, allowing the Colorado River to flood the Salton Basin. Today the Sea performs an important function as the sink for agricultural runoff; water levels are maintained by the runoff from the surrounding agricultural valleys. The Salton Sea salinity is high-nearly 1/4 saltier than ocean water-but it remains an important stopover point for migratory water birds, including several endangered species. The region also experiences several environmental problems. The recent increased demands for the limited Colorado River water threatens the amount of water allowed to flow into the Salton Sea. Increased salinity and decreased water levels could trigger several regional environmental crises. The agricultural flow into the Sea includes nutrients and agricultural by-products, increasing the productivity and likelihood of algae blooms. This image shows either a bloom, or suspended sediment (usually highly organic) in the water that has been stirred up by winds. Additional information: The Salton Sea A Brief Description of Its Current Conditions, and Potential Remediation Projects and Land Use Across the U.S.-Mexico Border Astronaut photograph STS111-E-5224 was taken by the STS-111 Space Shuttle crew that recently returned from the International Space Station. The image was taken June 12, 2002 using a digital camera. The image was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  12. Age-specific reproduction in female sea otters (`enhydra lutris`) from southcentral Alaska: Analysis of reproductive tracts. Marine mammal study 6-4. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Bodkin, J.L.; Mulcahy, D.M.; Lensink, C.J.

    1996-06-01

    We estimated age of sexual maturity and age-specific reproductive rates by examining carcasses and reproductive tracts from 177 female sea otters (Enhydra lutris). Carcasses were recovered from southcentral Alaska, primarily western Prince William Sound, following the T/V Exxon Valdez oil spill in 1989. Our estimates of the reproductive characteristics of female sea otters obtained by examination of reproductive tracts were similar to those in the literature based on in situ observations of marked individuals.

  13. Surveys of sea otters in the Gulf of Alaska in response to the Exxon Valdez oil spill. Marine mammal study 6-7. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

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

    1995-05-01

    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.

  14. Experiments to determine drift patterns and rates of recovery of sea otter carcasses following the Exxon Valdez oil spill. Marine mammal study 6-9. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

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

    1995-05-01

    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 monitoring 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.

  15. Hydrocarbon residues in tissues of sea otters (`enhydra lutris`) collected following the Exxon Valdez oil spill. Marine mammal study 6-16. Exxon Valdez oil spill state/federal natural resource damage assessment. Final report

    SciTech Connect

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

    1997-04-01

    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 and 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.

  16. 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, J.L.; Ballachey, B.E.; Esslinger, G.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.

  17. Technical report: Marine mammals study number 6. Movements of weanling and adult female sea otters in Prince William Sound, Alaska, after the t/v Exxon Valdez oil spill. Marine mammal study 6-12. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Monnett, C.; Rotterman, L.M.

    1995-05-01

    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 recently 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.

  18. 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, D.H.; Kloecker, K.A.; Esslinger, G.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

  19. 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

  20. 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. PMID:19527725

  1. A new pathogen transmission mechanism in the ocean: the case of sea otter exposure to the land-parasite Toxoplasma gondii.

    PubMed

    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

  2. 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. PMID:20071081

  3. Biomarkers of damage to sea otters in Prince William Sound, Alaska, following potential exposure to oil spilled from the Exxon Valdez. Marine mammal study 6-1. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Ballachey, B.E.

    1995-05-01

    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. 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.

  4. Improved reproductive success in otters (Lutra lutra), grey seals (Halichoerus grypus) and sea eagles (Haliaeetus albicilla) from Sweden in relation to concentrations of organochlorine contaminants.

    PubMed

    Roos, Anna M; Bäcklin, Britt-Marie V M; Helander, Björn O; Rigét, Frank F; Eriksson, Ulla C

    2012-11-01

    We studied indices of reproductive outcome in three aquatic species in relation to organochlorine concentrations during four decades. In female otters, the frequency of signs of reproduction increased after 1990. In grey seals, pregnancy rate increased 1990-2010 and uterine obstructions ceased after 1993. The frequency of uterine tumours was highest 1980-2000. The number of sea eagle nestlings per checked nest increased 1985-2000, while the frequency of desiccated eggs decreased. Organochlorine concentrations decreased at annual rates between 3.5 and 10.2%. The estimated mean concentration (mg/kg lw) for total-PCB decreased from 70 to 8 (otters), from 110 to 15 (seals) and from 955 to 275 (eagles). The corresponding concentrations for ΣDDT decreased from 3.4 to 0.2 (otters), from 192 to 2.8 (seals) and from 865 to 65 (eagles). This study adds evidence to support the hypothesis that PCBs and DDTs have had strong negative effects on the reproduction and population levels of these species. PMID:22842056

  5. 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

  6. 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

  7. Demographic responses to sea level rise in California

    SciTech Connect

    Constable, A. |; Van Arsdol, M.D. Jr.; Sherman, D.J.; Wang, J.; McMullin-Messier, P.A.; Rollin, L.

    1996-12-31

    Human consequences of sea level rise in California coastal counties reflect increasing population densities. Populations of coastal counties potentially affected by sea level rise are projected to increase from 26.2 million persons in 1990 to 63.3 million persons in 2040. Urbanization dominates Los Angeles and the South Coast and San Francisco Bay and Delta regions. California shoreline populations subject to potential disruption impacts of sea level rise are increasing rapidly. Enhanced risk zones for sea level rise are specified for the Oxnard Plain of Ventura County on the south coast of California. Four separate sea level rise scenarios are considered: (1) low (sea level rise only); (2) moderate (adding erosion); (3) high (adding erosion and storm surges); and (4) a maximum case, a 3 m enhanced risk zone. Population impacts are outlined for the 3 m zone. More serious impacts from storm surges are expected than from sea level rise and erosion. Stakeholders who support or oppose policies which may expose populations to sea level rise include energy, commercial, financial, industrial, public agency, private interest and governmental organizations. These organizations respond to extreme events from differing positions. Vested interests determine the degree of mitigation employed by stakeholders to defer impacts of sea level rise.

  8. California Sea Cliff Metrics: Mapping and Validation

    NASA Astrophysics Data System (ADS)

    Palaseanu, M.; Thatcher, C.; Danielson, J.; Logan, J. B.; Foxgrover, A. C.; Brock, J. C.; Barnard, P.

    2015-12-01

    Seacliff erosion is a serious hazard with implications for coastal management, and is often estimated using successive hand digitized cliff tops or bases (toe) to assess cliff retreat. We developed an automated procedure to extract the location of the cliff top from high resolution lidar-derived digital elevation models using transects generated at approximately 1-m intervals. The automated method to define cliff tops is repeatable, takes advantage of detailed topographic information within high-resolution elevation data, and is more efficient than hand-digitizing. To validate the results obtained from a 2010 aerial lidar survey, we conducted a terrestrial lidar (tlidar) survey at Bonny Doon beach near Santa Cruz California in 2014 and mapped the location of the cliff tops using real-time kinematic GPS. Bonny Doon beach has highly irregular cliffs, with several small sea caves and erosion features that were not distinguishable in the aerial lidar digital terrain model (DTM). We extracted the location of the cliff top from the tlidar point cloud along the same transects used previously to automatically derive cliff tops from the aerial lidar derived DTM. The minimum horizontal distance between the tlidar derived cliff top points and GPS points was calculated. The error measurements between GPS and terrestrial lidar are 0.19 m mean absolute error (MAE) and 0.51 m root mean square error (RMSE) respectively. The MAE and the RMSE between the GPS and aerial lidar cliff top points were 0.96 and 1.82 m respectively. The larger errors between aerial lidar cliff top points and GPS are likely due to the failure to remove all vegetation from the aerial lidar data, the positional accuracy of the aerial lidar, and a 4-year gap between surveys. The error assessment indicates that the automated procedure mapped the cliff top location successfully using both the aerial and terrestrial lidar, although the cliff top delineation based on the tlidar data was more accurate.

  9. 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

  10. 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.

  11. 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

    SciTech Connect

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

    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 significant 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.

  12. Airborne Doppler measurements of the central California extended sea breeze

    NASA Technical Reports Server (NTRS)

    Carroll, J. J.

    1985-01-01

    One data acquisition flight was executed in the late summer of 1984. The flight paths were designed to obtain measurements of the extended sea breeze penetration into the central valley of California over several hours. Data from this flight are being processed at Marshall Space Flight Center prior to release for analysis.

  13. Diagnostic testing for Leptospirosis in California sea lions (Zalophus californianus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leptospirosis is a relatively common bacterial disease in California sea lions (Zalophus californianus); however, there remain gaps in our understanding of maintenance hosts relative to animals demonstrating clinical disease. To effectively study the epidemiology of leptospirosis in any species, a s...

  14. 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…

  15. Sea Floor off San Diego, California

    USGS Publications Warehouse

    Dartnell, Peter; Gibbons, Helen

    2009-01-01

    Ocean-floor image generated from multibeam-bathymetry data acquired by the U.S. Geological Survey (USGS); Woods Hole Oceanographic Institution; Scripps Institution of Oceanography; California State University, Monterey Bay; and Fugro Pelagos. To learn more, visit http://pubs.usgs.gov/sim/2007/2959/.

  16. Estimating sustainable bycatch rates for California sea lion populations in the Gulf of California.

    PubMed

    Underwood, Jared G; Hernandez Camacho, Claudia J; Aurioles-Gamboa, David; Gerber, Leah R

    2008-06-01

    Commercial and subsistence fisheries pressure is increasing in the Gulf of California, Mexico. One consequence often associated with high levels of fishing pressure is an increase in bycatch of marine mammals and birds. Fisheries bycatch has contributed to declines in several pinniped species and may be affecting the California sea lion (Zalophus californianus) population in the Gulf of California. We used data on fisheries and sea lion entanglement in gill nets to estimate current fishing pressure and fishing rates under which viable sea lion populations could be sustained at 11 breeding sites in the Gulf of California. We used 3 models to estimate sustainable bycatch rates: a simple population-growth model, a demographic model, and an estimate of the potential biological removal. All models were based on life history and census data collected for sea lions in the Gulf of California. We estimated the current level of fishing pressure and the acceptable level of fishing required to maintain viable sea lion populations as the number of fishing days (1 fisher/boat setting and retrieving 1 day's worth of nets) per year. Estimates of current fishing pressure ranged from 101 (0-405) fishing days around the Los Machos breeding site to 1887 (842-3140) around the Los Islotes rookery. To maintain viable sea lion populations at each site, the current level of fishing permissible could be augmented at some sites and should be reduced at other sites. For example, the area around San Esteban could support up to 1428 (935-2337) additional fishing days, whereas fishing around Lobos should be reduced by at least 165 days (107-268). Our results provide conservation practitioners with site-specific guidelines for maintaining sustainable sea lion populations and provide a method to estimate fishing pressure and sustainable bycatch rates that could be used for other marine mammals and birds. PMID:18410402

  17. Population dynamics of California sea otters and a model for the risk of oil spills

    SciTech Connect

    Brody, A.J.

    1988-01-01

    In an effort to estimate parameters in the density dependence function used in the simulation model, an analysis of the recent historical growth and range expansion of the population was undertaken. Simple deterministic models that included feedback between population growth and range expansion were built, some including a density independent mortality rate after 1972 to investigate the effect of incidental drowning in fishing-nets. Analysis of model output indicated that the density dependence function in the actual population is probably very rectangular. Range length may hamper the dispersal of young males out of the central part of the range. The apparent decline in population in the 1970's may be due to this slowing range expansion coinciding with the onset of fishing-net mortality.

  18. 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.

  19. Integrated Science Investigations of the Salton Sea, California, USA

    NASA Astrophysics Data System (ADS)

    Barnum, D.

    2006-12-01

    The Salton Sea is the latest waterbody to be formed by Colorado River floodwaters within the Salton Trough. Over the past 100 years, floodwaters have been replaced by agricultural drainage water and municipal discharges so that today, most of the water reaching the Salton Sea is agricultural drainwater flowing down the New, Alamo and Whitewater Rivers. An evaporation of about 6 feet per year and inputs of more than 4 million tons of salt per year have increased salinity of the waters of the Salton Sea. The current salinity level of approximately 46 parts per thousand is about 25% more saline than ocean water. Diverting water from the Imperial Valley agricultural lands to urban Southern California, and anticipated loss of inflows from Mexico and increasing water conservation activities will result in less water flowing into the Salton Sea. A Restoration Program is being conducted to evaluate the effects of diminished inflows on the Salton Sea Ecosystem and recommend alternatives to avoid or minimize those effects. The Salton Sea has become increasingly important as habitat for migratory birds because of wetland losses. California has lost approximately 91% of interior wetland acreage from pre-settlement until the mid-1980's. The Salton Sea provides critical habitat linking distant wetlands of Pacific and Central Flyways to wintering habitats in Mexico and Central and South America. More than 400 species of birds have been observed in the Salton Sea Ecosystem. Large percentages of the populations for several bird species such as the endangered Yuma Clapper Rail, the Eared Grebe, Snowy Plover and American White Pelican utilize the Salton Sea. Approximately 20 species of conservation concern utilize the Salton Sea ecosystem. Fish-eating birds such as Great Blue Herons, California Brown Pelicans, Double-crested Cormorants and several species of egrets are highly dependent upon the fishery of the Salton Sea. The Salton Sea fishery is now primarily comprised of tilapia

  20. 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. PMID:25660039

  1. Risk factors for an outbreak of leptospirosis in California sea lions (Zalophus californianus) in California, 2004.

    PubMed

    Norman, Stephanie A; DiGiacomo, Ronald F; Gulland, Frances M D; Meschke, John Scott; Lowry, Mark S

    2008-10-01

    Leptospirosis has been reported in California sea lions (Zalophus californianus) since 1970; however, the source of infection and mode of transmission remain unknown. To elucidate these features, demographic and environmental risk factors for leptospirosis were evaluated. California sea lion stranding records from northern California for 2004 were used to identify cases of leptospirosis (n = 316) and controls (n = 143). Demographic characteristics (age class, sex) and environmental factors, representing surrogates for exposure to dogs, cattle, rainfall, and freshwater sources, were compared between cases and controls with the use of a geographic information system (GIS) and logistic regression. Multivariate analyses revealed that summer and autumn seasons, juvenile age class, male sex, high dog-park density, and close proximity to dog parks were significantly associated with leptospirosis in sea lions, whereas county farmland cattle density, rainfall levels 30 days prior to stranding, human density, and proximity to freshwater sources were not associated. Thus, dogs and dog parks, or factors associated with them, might be further investigated to assess their relationship to leptospirosis in sea lions. PMID:18957639

  2. 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

    SciTech Connect

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

    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 would 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.

  3. Sea level, paleogeography, and archeology on California's Northern Channel Islands

    USGS Publications Warehouse

    Reeder-Myers, Leslie; Erlandson, Jon M.; Muhs, Daniel R.; Rick, Torben C.

    2015-01-01

    Sea-level rise during the late Pleistocene and early Holocene inundated nearshore areas in many parts of the world, producing drastic changes in local ecosystems and obscuring significant portions of the archeological record. Although global forces are at play, the effects of sea-level rise are highly localized due to variability in glacial isostatic adjustment (GIA) effects. Interpretations of coastal paleoecology and archeology require reliable estimates of ancient shorelines that account for GIA effects. Here we build on previous models for California's Northern Channel Islands, producing more accurate late Pleistocene and Holocene paleogeographic reconstructions adjusted for regional GIA variability. This region has contributed significantly to our understanding of early New World coastal foragers. Sea level that was about 80–85 m lower than present at the time of the first known human occupation brought about a landscape and ecology substantially different than today. During the late Pleistocene, large tracts of coastal lowlands were exposed, while a colder, wetter climate and fluctuating marine conditions interacted with rapidly evolving littoral environments. At the close of the Pleistocene and start of the Holocene, people in coastal California faced shrinking land, intertidal, and subtidal zones, with important implications for resource availability and distribution.

  4. Sea level, paleogeography, and archeology on California's Northern Channel Islands

    NASA Astrophysics Data System (ADS)

    Reeder-Myers, Leslie; Erlandson, Jon M.; Muhs, Daniel R.; Rick, Torben C.

    2015-03-01

    Sea-level rise during the late Pleistocene and early Holocene inundated nearshore areas in many parts of the world, producing drastic changes in local ecosystems and obscuring significant portions of the archeological record. Although global forces are at play, the effects of sea-level rise are highly localized due to variability in glacial isostatic adjustment (GIA) effects. Interpretations of coastal paleoecology and archeology require reliable estimates of ancient shorelines that account for GIA effects. Here we build on previous models for California's Northern Channel Islands, producing more accurate late Pleistocene and Holocene paleogeographic reconstructions adjusted for regional GIA variability. This region has contributed significantly to our understanding of early New World coastal foragers. Sea level that was about 80-85 m lower than present at the time of the first known human occupation brought about a landscape and ecology substantially different than today. During the late Pleistocene, large tracts of coastal lowlands were exposed, while a colder, wetter climate and fluctuating marine conditions interacted with rapidly evolving littoral environments. At the close of the Pleistocene and start of the Holocene, people in coastal California faced shrinking land, intertidal, and subtidal zones, with important implications for resource availability and distribution.

  5. Evidence of Leptospira interrogans infection in California sea lion pups from the Gulf of California.

    PubMed

    Acevedo-Whitehouse, Karina; de la Cueva, Horacio; Gulland, Frances M D; Aurioles-Gamboa, David; Arellano-Carbajal, Fausto; Suarez-Güemes, Francisco

    2003-01-01

    Forty-two urine and 96 blood and serum samples were obtained from California sea lion (Zalophus californianus) pups from the Gulf of California during the 2000 reproductive season. Antibody prevalence to 13 serovars of Leptospira interrogans was determined by microagglutination tests (MAT); presence of pathogenic leptospires was detected by polymerase chain reaction (PCR). Samples with antibody titers > or = 1:25 or 115 bp fragments on ethidium bromidestained 1.5% agarose gels were considered positive. Antibody prevalence was 54% overall with highest prevalence against serovar cynopteri (50% of all positive reactions). Highest antibody titers (1:50) were detected against serovars cynopteri and pomona. Polymerase chain reaction products were observed in two of 42 urine samples, six of 96 blood samples, and one of 96 serum samples. Presence of PCR products in blood and serum was demonstrated in pups that were seronegative. Kruskall-Wallis tests and corresponding post hoc Tukey tests (alpha = 0.05) showed that prevalence of leptospirosis was significantly different among all rookeries. The high seroprevalence (54%), low antibody titers (maximum 1:50), absence of pups showing clinical signs indicative of the disease, and lack of recent reports of increased mortality of sea lions in the Gulf of California are suggestive of the presence of enzootic host-adapted serovars. Crowding in rookeries as well as the presence of bats and rodents on some of the islands may explain infection by L. interrogans (sensu lato) and some of the differences in seroprevalence among reproductive rookeries. PMID:12685078

  6. Antibodies against Leptospira interrogans in California sea lion pups from Gulf of California.

    PubMed

    Godínez, C R; Zelaya de Romillo, B; Aurioles-Gamboa, D; Verdugo-Rodríguez, A; Rodríguez-Reyes, E A; De la Peña-Moctezuma, A

    1999-01-01

    One hundred and twenty-five serum samples from California sea lion (Zalophus californianus californianus) pups, and one from an adult female from eight reproductive rookeries located in seven islands in the Gulf of California (Mexico), were collected during the 1994-96 reproductive seasons. These were tested for antibodies to 19 serovars of Leptospira interrogans using a Microscopic Agglutination Test (MAT). Forty-one samples (32%) had antibody levels from 1:20 to 1:320 to one or more serovars. The most frequently detected serotypes were Leptospira interrogans hardjo (n = 13), cynopteri (8), ballum (6), and szwajizak (5). Serovars with the highest prevalence were Leptospira interrogans hardjo and serjoe (1:320), ballum (1:160), and cynopteri, girppotyphosa, and tarassovi (1:80). Based on these results, exposure of sea lions to L. interrogans serovar hardjo seems to be relatively common among colonies located in the islands of the Gulf of California in contrast with those located on the Pacific coast, where the most frequently detected serovar is L. interrogans serovar pomona. PMID:10073358

  7. Late Holocene Sea Temperatures along the Central California Coast

    NASA Astrophysics Data System (ADS)

    Jones, Terry L.; Kennett, Douglas J.

    1999-01-01

    Mussel shells from central California coastal archaeological sites record changes in sea surface temperatures in the past 2000 years. Water temperatures, inferred from oxygen isotopes in the shells, were about 1°C cooler than present and stable between 2000 and 700 yr ago. Between about 700 and 500 yr ago, seasonal variation was greater than present, with extremes above and below historic levels. Water temperatures were 2-3°C cooler than today 500-300 yr ago. The interval of variable sea temperatures 700-500 yr ago partially coincided with an interval of drought throughout central California. A coincident disruption in human settlement along the coast suggests movements of people related to declining water sources. Quantities of fish bone in central coast middens dating to this same period are high relative to other periods, and the remains of northern anchovies, a species sensitive to changing oceanographic conditions, are also abundant. The continued use of local fisheries suggests that changes in settlement and diet were influenced more by drought than by a decrease in marine productivity, as fish provided a staple during an interval of low terrestrial productivity.

  8. Geographical dissemination of Leptospira interrogans serovar Pomona during seasonal migration of California sea lions.

    PubMed

    Zuerner, Richard L; Cameron, Caroline E; Raverty, Stephen; Robinson, John; Colegrove, Kathleen M; Norman, Stephanie A; Lambourn, Dyanna; Jeffries, Steven; Alt, David P; Gulland, Frances

    2009-05-28

    Leptospirosis is one of the most widespread bacterial zoonoses in the world and affects most mammalian species. Although leptospirosis is well documented and characterized in terrestrial species, less information is available regarding the distribution and impact of leptospirosis in marine mammals. Additionally, the role of animal migrations on the geographical spread of leptospirosis has not been reported. Periodic epizootic outbreaks of acute leptospirosis among California sea lions (Zalophus californianus) have been reported since 1971. In this study, we collected samples from California sea lions stranded along the Pacific coast of North America during the most recent epidemic in 2004, and maintained leptospirosis surveillance of the California sea lion population along the California coast through 2007. Several isolates of Leptospira interrogans serovar Pomona were obtained from kidney and urine samples collected during this study, a finding consistent with serological evidence that California sea lions are persistently exposed to this leptospiral serovar. Combined, these data support a model whereby California sea lions are maintenance hosts for L. interrogans serovar Pomona, yet periodically undergo outbreaks of acute infection. During the 2004 outbreak, the incidence of new leptospirosis cases among California sea lions coincided with the seasonal movement of male sea lions from rookeries along the coast of central and southern California north as far as British Columbia. These data show that seasonal animal movement contributes to the distribution of leptospirosis across a large geographical region. PMID:19186009

  9. Regional Sea Level Variation: California Coastal Subsidence (Invited)

    NASA Astrophysics Data System (ADS)

    Blewitt, G.; Hammond, W. C.; Nerem, R.

    2013-12-01

    Satellite altimetry over the last two decades has measured variations in geocentric sea level (GSL), relative to the Earth system center of mass, providing valuable data to test models of physical oceanography and the effects of global climate change. The societal impacts of sea level change however relate to variations in local sea level (LSL), relative to the land at the coast. Therefore, assessing the impacts of sea level change requires coastal measurements of vertical land motion (VLM). Indeed, ΔLSL = ΔGSL - ΔVLM, with subsidence mapping 1:1 into LSL. Measurements of secular coastal VLM also allow tide-gauge data to test models of GSL over the last century in some locations, which cannot be provided by satellite data. Here we use GPS geodetic data within 15 km of the US west coast to infer regional, secular VLM. A total of 89 GPS stations met the criteria that time series span >4.5 yr, and do not have obvious non-linear variation, as may be caused by local instability. VLM rates for the GPS stations are derived in the secular reference frame ITRF2008, which aligns with the Earth system center of mass to ×0.5 mm/yr. We find that regional VLM has different behavior north and south of the Mendocino Triple Junction (MTJ). The California coast has a coherent regional pattern of subsidence averaging 0.5 mm/yr, with an increasing trend to the north. This trend generally matches GIA model predictions. Around San Francisco Bay, the observed coastal subsidence of 1.0 mm/yr coherently decreases moving away from the Pacific Ocean to very small subsidence on the east shores of the bay. This gradient is likely caused by San Andreas-Hayward Fault tectonics, and possibly by differential surface loading across the bay and Sacramento-San Joachim River Delta. Thus in addition to the trend in subsidence from GIA going northward along the California coast, tectonics may also play a role where the plate boundary fault system approaches the coast. In contrast, we find that VLM

  10. Sea surface and remotely sensed temperatures off Cape Mendocino, California

    NASA Technical Reports Server (NTRS)

    Breaker, L. C.; Arvesen, J. C.; Frydenlund, D.; Myers, J. S.; Short, K.

    1985-01-01

    During September 3 to 5, 1979, a multisensor oceanographic experiment was conducted off Cape Mendocino, California. The purpose of this experiment was to validate the use of remote sensing techniques over an area along the U.S. west coast where coasted upwelling is known to be intense. Remotely sensed mutlispectral data, including thermal infrared imagery, were collected above an upwelling feature off Cape Mendocino. Data were acquired from the TIRNOS-N and NOAA-6 polar orbiting satellites, the NASA Ames Research Center's high altitude U-2 aircraft, and a U.S. Coast Guard C-130 aircraft. Supporting surface truth data over the same feature were collected aboard the National Oceanic and Atmospheric Administration (NOAA) ship, OCEANOGRAPHER. Atmospheric soundings were also taken aboard the ship. The results indicate that shipboard measurements of sea surface temperatures can be reproduction within 1 C or better through remote observation of absolute infrared radiance values (whether measured aboard the NOAA polar orbiting satellite, the U-2 aircraft, or the Coast Guard aircraft) by using appropriate atmospheric corrections. Also, the patterns of sea surface temperature which were derived independently from the various remote platforms provide a consistent interpretation of the surface temperature field.

  11. 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)

  12. Asymptomatic and chronic carriage of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus).

    PubMed

    Prager, K C; Greig, Denise J; Alt, David P; Galloway, Renee L; Hornsby, Richard L; Palmer, Lauren J; Soper, Jennifer; Wu, Qingzhong; Zuerner, Richard L; Gulland, Frances M D; Lloyd-Smith, James O

    2013-05-31

    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 months of July and December, with major epizootics occurring every 3-5 years. Genetic and serological data suggest that Leptospira interrogans serovar Pomona is the infecting serovar and is enzootic in the California sea lion population, although the mechanism of persistence is unknown. We report asymptomatic carriage of Leptospira in 39% (33/85) of wild, free-ranging sea lions sampled during the epizootic season, and asymptomatic seroconversion with chronic asymptomatic carriage in a rehabilitated sea lion. This is the first report of asymptomatic carriage in wild, free-ranging California sea lions and the first example of seroconversion and asymptomatic chronic carriage in a sea lion. Detection of asymptomatic chronic carriage of Leptospira in California sea lions, a species known to suffer significant disease and mortality from the same Leptospira strain, goes against widely-held notions regarding leptospirosis in accidental versus maintenance host species. Further, chronic carriage could provide a mechanism for persistent circulation of Leptospira in the California sea lion population, particularly if these animals shed infectious leptospires for months to years. PMID:23419822

  13. Multicentric neurofibromatosis with rectal prolapse in a California sea lion (Zalophus californianus).

    PubMed

    Rush, Elizabeth M; Ogburn, Anna L; Garner, Michael M

    2012-03-01

    An approximately 31-yr-old California sea lion (Zalophus californianus) with a history of chronic visual impairment and corneal disease presented with slow onset, progressive neurologic deficits. Treatment for rear flipper paresis was not effective and the animal was euthanatized. Histopathologic findings included hepatocellular and biliary neoplasia, ocular amyloidosis, adrenal adenoma and pheochromocytoma, and spinal cord changes consistent with multicentric neurofibromatosis. This is the first documentation of these conditions in a California sea lion. PMID:22448517

  14. Salton Sea and Imperial Valley, California as seen from the Apollo 7 spacecra

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Salton Sea and Imperial Valley area of southern California, including a portion of northern Baja California, Mexico, as seen from the Apollo 7 spacecraft during its 17th revolution of the earth. Photographed from an altitude of 125 nautical miles, at ground elapsed time of 27 hours.

  15. An otter tragedy. [Environmental effects of oil spills

    SciTech Connect

    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. 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.

  16. Impact of Interdecadal Sea Level and Sea Surface Temperature Variability on Primary Productivity and Harmful Algal Blooms in Southern California

    NASA Astrophysics Data System (ADS)

    Perry, K. L.

    2014-12-01

    Harmful Algal Blooms (HABs) are increasing in frequency and intensity on global, regional and local scales. Although climate change has been suggested as one of the key factors, very few interdecadal studies comparing HABs to low frequency physical forcing have been performed. Interannual to interdecadal variability in sea level and sea surface temperature along the Southern California Coast have been shown to have high correlation with the El Nino-La Nina signal. This is important in the study of phytoplankton, because abnormally low sea level corresponds to increased sea surface nutrient concentrations in this region. The California current is stronger during these times, and the higher nutrient water found to the north is advected southward. We have determined that primary productivity is most highly correlated with interdecadal sea level variability derived from tide gage data at a lag of approximately 2 months. This is consistent with previous zooplankton studies. In preparation for a potential El Nino event, we have expanded our analysis to include parameters such as sea surface temperature, salinity and nutrient concentrations from spaceborne and in situ instruments. We have also expanded our research to allow for analysis of several of the most prevalent HAB species. This work is the first step in our effort to create a model to predict and locate Southern California HAB events in the future.

  17. 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...

  18. 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

  19. 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. PMID:20226596

  20. 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

  1. Transformation of the genital epithelial tract occurs early in California sea lion development.

    PubMed

    Barragán-Vargas, Cecilia; Montano-Frías, Jorge; Ávila Rosales, Germán; Godínez-Reyes, Carlos R; Acevedo-Whitehouse, Karina

    2016-03-01

    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

  2. Isolation by distance among California sea lion populations in Mexico: redefining management stocks.

    PubMed

    González-Suárez, M; Flatz, R; Aurioles-Gamboa, D; Hedrick, P W; Gerber, L R

    2009-03-01

    Understanding the spatial structure of a population is critical for effective assessment and management. However, direct observation of spatial dynamics is generally difficult, particularly for marine mammals. California sea lions (Zalophus californianus) are polygynous pinnipeds distributed along the Pacific coast of North America. The species' range has been subdivided into three management stocks based on differences in mitochondrial DNA, but to date no studies have considered nuclear genetic variation, and thus we lack a comprehensive understanding of gene flow patterns among sea lion colonies. In light of recent population declines in the Gulf of California, Mexico, it is important to understand spatial structure to determine if declining sea lion colonies are genetically isolated from others. To define population subdivision and identify sex biases in gene flow, we analysed a 355-bp sequence of the mitochondrial DNA control region and 10 polymorphic microsatellite loci from 355 tissue samples collected from six colonies distributed along Mexican waters. Using a novel approach to estimate sex biases in gene flow, we found that male sea lions disperse on average 6.75 times more frequently than females. Analyses of population subdivision strongly suggest a pattern of isolation by distance among colonies and challenge current stock definitions. Based on these results, we propose an alternative classification that identifies three Mexican management units: Upper Gulf of California, Southern Baja Peninsula, and Upper Pacific Coast of Baja. This revised classification should be considered in future assessment and management of California sea lion populations in Mexican waters. PMID:19226320

  3. Effects of tectonism, eustatic sea level fluctuations, and climatic changes on Paleogene sedimentation in California

    SciTech Connect

    Nilsen, T.H.

    1988-03-01

    Paleogene sedimentation in California was strongly influenced by syndepositional tectonism, eustatic sea level changes, and variations in climate. Tectonic activity was most important in controlling sedimentation in basins that developed in mobile areas such as the Salinian block, Coast Ranges, Transverse Ranges, southern California borderland, and along the continental slope adjacent to the trench that formed the California plate margin. Although plutonism had largely terminated in California by Paleogene time, continued uplift of the Mesozoic batholithic complexes of the Klamath Mountains, Sierra Nevada, Mojave Desert, and Salinian block yielded abundant plutoniclastic detritus to paleogene basins. Accretion of exotic terranes during the Paleocene and early eocene, major uplift of the Franciscan assemblage in various parts of California during the Eocene, syndepositional faulting in numerous areas, angular unconformities, and coarse clastic sequences that include alluvial-fan and fault-scarp breccias are features that indicate major tectonic control of sedimentation in Paleogene basins. Renewed volcanism, starting during the late Eocene in northern California in the ancestral Cascade volcanic arc, and in the late Oligocene in many other parts of California, began to supply abundant volcaniclastic sediments locally. In some relatively stable areas, such as the flanks of the Peninsular Ranges and parts of the San Joaquin and Sacramento basins, the effects of global sea level changes on the sedimentary record are easily discerned. Climatic cycles had significant control over Paleogene sedimentation in some of these stable areas.

  4. 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.

  5. Dissecting the Influences of Climate and Demography on the Dynamics of Leptospirosis in California Sea Lions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  6. Asymptomatic and chronic carriage of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  7. Antibiotic efficacy in eliminating leptospiruria in California sea lions (Zalophus californianus) stranding with leptospirosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infection of California sea lions with leptospirosis can result in stranding and death of the animals. Shedding of the infectious organism contributes to spread of the disease to other animals and also poses a threat to human health. This is both for the public interacting with stranded animals and ...

  8. 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 (<...

  9. 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.

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

    PubMed Central

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

    2012-01-01

    SUMMARY 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-O2) 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 O2 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. PMID:22189769

  11. 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

  12. Food limitation of sea lion pups and the decline of forage off central and southern California.

    PubMed

    McClatchie, Sam; Field, John; Thompson, Andrew R; Gerrodette, Tim; Lowry, Mark; Fiedler, Paul C; Watson, William; Nieto, Karen M; Vetter, Russell D

    2016-03-01

    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

  13. The Otter Annotation System

    PubMed Central

    Searle, Stephen M.J.; Gilbert, James; Iyer, Vivek; Clamp, Michele

    2004-01-01

    With the completion of the human genome sequence and genome sequence available for other vertebrate genomes, the task of manual annotation at the large genome scale has become a priority. Possibly even more important, is the requirement to curate and improve this annotation in the light of future data. For this to be possible, there is a need for tools to access and manage the annotation. Ensembl provides an excellent means for storing gene structures, genome features, and sequence, but it does not support the extra textual data necessary for manual annotation. We have extended Ensembl to create the Otter manual annotation system. This comprises a relational database schema for storing the manual annotation data, an application-programming interface (API) to access it, an extensible markup language (XML) format to allow transfer of the data, and a server to allow multiuser/multimachine access to the data. We have also written a data-adaptor plugin for the Apollo Browser/Editor to enable it to utilize an Otter server. The otter database is currently used by the Vertebrate Genome Annotation (VEGA) site (http://vega.sanger.ac.uk), which provides access to manually curated human chromosomes. Support is also being developed for using the AceDB annotation editor, FMap, via a perl wrapper called Lace. The Human and Vertebrate Annotation (HAVANA) group annotators at the Sanger center are using this to annotate human chromosomes 1 and 20. PMID:15123593

  14. Can large scale sea ice cover changes affect precipitation patterns over California?

    NASA Astrophysics Data System (ADS)

    Cvijanovic, I.; Bonfils, C.; Lucas, D. D.; Santer, B. D.; Chiang, J. C. H.

    2015-12-01

    Pronounced Arctic sea ice loss since the beginning of the satellite era has intensified the interest into whether these high latitude changes can significantly influence the weather and climate far from the Arctic. Current attempts to demonstrate statistically significant remote responses to sea ice changes have been hindered by factors such as large high latitude variability, relatively short observational datasets, and model limitations in adequately representing current sea ice changes. In this study, we sample uncertainty in sea ice physics parameters and variability in atmospheric initial conditions to obtain an ensemble of simulations with substantially different states of Arctic and Antarctic sea ice cover. This large ensemble isolates a robust, statistically significant climate change response arising from changes in sea ice cover only. Our results show a significant link between Arctic and Antarctic sea ice cover changes and precipitation across the tropical Atlantic and Pacific basins, the Sahel, and the west coast of the United States. For example, large Arctic sea ice decline leads to a northward shift of the tropical convergence zone, increased subsidence over the southwest United States and a geopotential anomaly over the North Pacific; with all of these factors resulting in significant drying over California. We conclude that high-latitude sea ice cover changes are an important driver of low-latitude precipitation. Consequently, reliable predictions of future precipitation changes over areas such as California (and the Sahel) will strongly depend on our ability to adequately simulate both Arctic and Antarctic sea ice changes. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and is released as LLNL-ABS-675694.

  15. Heavy metal accumulation in four species of sea turtles from the Baja California peninsula, Mexico.

    PubMed

    Gardner, Susan C; Fitzgerald, Sionnan L; Vargas, Baudilio Acosta; Rodríguez, Lia Méndez

    2006-02-01

    Heavy metals were assessed in four species of sea turtles from the Baja California Peninsula, Mexico, representing the first report of heavy metal concentrations in tissues of post-yearling sea turtles from the Eastern Pacific. Concentrations of Cd measured in C. mydas kidney (653 microg/g dry wt) were the highest ever reported for any sea turtle species. Cd accumulated preferentially in kidney and the ratios of kidney to liver Cd in Baja California turtles were among the highest reported for sea turtles globally. Zn, Ni, and Mn concentrations were also significantly higher in kidney than other tissues, while Cu and Fe were greatest in liver, and all metals were lowest in muscle. With the exception of one value (69.9 microg/g in kidney of C. caretta), Pb was low in all tissues from Baja California. In comparisons across species, kidney of C. mydas had greater Zn and Ni concentrations as compared to other species, although there was no difference in liver metal levels among the species. Positive correlations were detected in the concentrations of Cd, Cu and Ni with the straight carapace length of C. caretta. PMID:16502335

  16. Results from shallow research drilling at Inyo Domes, Long Valley Caldera, California and Salton Sea geothermal field, Salton Trough, California

    SciTech Connect

    Younker, L.W.; Eichelberger, J.C.; Kasameyer, P.W.; Newmark, R.L.; Vogel, T.A.

    1987-09-01

    This report reviews the results from two shallow drilling programs recently completed as part of the United States Department of Energy Continental Scientific Drilling Program. The purpose is to provide a broad overview of the objectives and results of the projects, and to analyze these results in the context of the promise and potential of research drilling in crustal thermal regimes. The Inyo Domes drilling project has involved drilling 4 shallow research holes into the 600-year-old Inyo Domes chain, the youngest rhyolitic event in the coterminous United States and the youngest volcanic event in Long Valley Caldera, California. The purpose of the drilling at Inyo was to understand the thermal, chemical and mechanical behavior of silicic magma as it intrudes the upper crust. This behavior, which involves the response of magma to decompression and cooling, is closely related to both eruptive phenomena and the establishment of hydrothermal circulation. The Salton Sea shallow research drilling project involved drilling 19 shallow research holes into the Salton Sea geothermal field, California. The purpose of this drilling was to bound the thermal anomaly, constrain hydrothermal flow pathways, and assess the thermal budget of the field. Constraints on the thermal budget links the local hydrothermal system to the general processes of crustal rifting in the Salton Trough.

  17. Molluscan evidence for a late Pleistocene sea-level lowstand from Monterey Bay, central California

    USGS Publications Warehouse

    Powell, Charles L.

    1994-01-01

    One hundred and twenty-three molluscan taxa are reported from four samples collected from a sea level lowstand deposit located between 100 m and 300 m below sea level in Monterey Bay, central California. Ecological interpretations of these mollusks suggest temperatures essentially equivalent to those from Puget Sound, Washington, to southern British Columbia; much cooler water than exists in Monterey Bay today; and water depths of about 10 to 50 m. Chlamys rubida from these deposits yield a 14C age determination of about 17,000 yr B. P. This age is generally equivalent to a worldwide sea level lowstand between 20,000 and 15,000 yr B. P. of at least 100 m below modern sea level. The cooler and shallow-water aspect of the lowstand molluscan fauna is in full accord with the late Pleistocene paleogeography of Monterey Bay.

  18. Evaporation and radiation measurements at Salton Sea, California

    USGS Publications Warehouse

    Sturrock, Alex M.

    1978-01-01

    Evaporation from Salton Sea, Calif. was computed for a 539-day period between duly 14, 1967, and January 2, 1969, by use of energy-budget, mass-transfer, and water-budget methods. The total evaporation computed by the three methods agreed within 5 percent. For computing evaporation by the mass-transfer method, vapor pressure measured at raft stations on the sea was considered to be more representative of the conditions over the sea than vapor pressure measured at land stations. The values of heat transfer to and from the bed were used in energy-budget computations. The inclusion of these heat transfer values improved the correlation of evaporation computed by the energy-budget and water-budget methods. Monthly evaporation computed by the energy budget method for 1968 showed that the Salton Sea exhibited a double-wave evaporation similar to that of oceans in the same latitude. Weekly and monthly comparisons were made to determine if radiation measured by the flat-plate radiometer is seasonally biased. Weekly totals of radiation from three flat-plate radiometers were compared to values of a Cummings Radiation Integrator. Monthly totals of radiation for each of the two types of instruments were compared to an empirical method for determining radiation. These comparisons indicate that the measurements of radiation by the flat-plate radiometer are not seasonally biased, and that the Cummings Radiation Integrator gives reliable measurements of radiation for periods as short as 1 week. The net incoming radiation was measured at three stations around the Salton Sea. The areal variation was less than 1 percent on an annual basis and the largest weekly variation was less than 6 percent. An empirical mass-transfer coefficient, N, was determined from energy-budget measurements. The value of this coefficient to give evaporation in inches per day is 0.00245 when the windspeed is expressed in miles per hour and vapor pressure is expressed in millibars. The coefficient is valid

  19. At-sea distribution and abundance of seabirds off southern California: A 20-year comparison

    USGS Publications Warehouse

    Mason, J.W.; McChesney, G.J.; McIver, W.R.; Carter, H.R.; Takekawa, J.Y.; Golightly, R.T.; Ackerman, J.T.; Orthmeyer, D.L.; Perry, W.M.; Yee, J.L.; Pierson, M.O.; McCrary, M.D.

    2007-01-01

    We conducted aerial at-sea and coastal surveys to examine the distribution and abundance of seabirds off southern California, from Cambria, California, to the Mexican border. From May 1999-January 2002, we flew 102 d, covered >54,640 km of transect lines, and conducted nine complete surveys of southern California in January, May, and September. We identified 54 species comprising 12 families and counted >135,000 individuals. Seabird densities were greater along island and mainland coastlines than at sea and were usually greatest in January surveys. Densities were greatest at sea near the northern Channel Islands in January and north of Point Conception in May, and lowest in the southwestern portion of the Southern California Bight in all survey months. On coastal transects, seabird densities were greatest along central and southern portions of the mainland coastline from Point Arguello to Mexico. We estimated that 981,000 ?? 144,000 (x?? ?? SE) seabirds occurred in the study area in January, 862,000 ?? 95,000 in May, and 762,000 ?? 72,000 in September. California Gulls (Larus californicus), Western Grebes (Aechmophorus occidentalis), and Cassin's Auklets (Ptychoramphus aleuticus) were most abundant in January surveys at sea, whereas Sooty and Short-tailed shearwaters (Puffinus griseus and P. tenuirostris), phalaropes (Phalaropus spp.), and Western Gulls (Larus. occidentalis) were most abundant in May and September surveys. On coastal transects, California Gulls, Western Grebes, Western Gulls, and Surf Scoters (Melanitta perspicillata) were most abundant in January; Western Grebes, Western Gulls, Surf Scoters, and Brown Pelicans (Pelecanus occidentalis) were most abundant in May; and Sooty Shearwaters, Short-tailed Shearwaters, Western Gulls, Western Grebes, Brown Pelicans, and Heermann's Gulls (Larus heermanni) were most abundant in September. Compared to historical seabird densities collected in the same area two decades ago (1975-1978 and 1980-1983), abundance

  20. Normal Morphology and Hormone Receptor Expression in the Male California sea lion (Zalophus californianus) Genital Tract

    PubMed Central

    Colegrove, Kathleen M.; Gulland, Frances M. D.; Naydan, Diane K.; Lowenstine, Linda J.

    2010-01-01

    Histomorphology and estrogen α (ER α), and progesterone receptor (PR) expression were evaluated in free-ranging stranded male California sea lions (Zalophus californianus). Hormone receptor expression was evaluated using an immunohistochemical technique with monoclonal antibodies. Estrogen and progesterone receptors were identified in the efferent ductules, prostate gland, corpus cavernosa, corpus spongiosium, penile urethra, and in the epithelium and stroma of both the penis and prepuce. In the some tissues, ER α expression was more intense in the stroma, emphasizing the importance of the stroma in hormone – mediated growth and differentiation of reproductive organs. To our knowledge, this is the first study to localize ER α and PR to the epithelium of the glans penis. The results of this investigation add to the general knowledge of male California sea lion reproduction and suggest that estrogens could have a role in the function of the male reproductive tract. PMID:19768750

  1. Sea-cliff erosion at Pacifica, California caused by 1997/98 El Nino storms

    USGS Publications Warehouse

    Snell, Charles B.; Lajoie, K.R.; Medley, Edward W.

    2000-01-01

    Twelve homes were constructed in 1949 at the top of a sea cliff along Esplanade Drive in the City of Pacifica, located on the northern coast of San Mateo County, California. During the heavy storms of the 1997/98 El Nino winter, a severe episode of cliff retreat undermined seven homes and threatened three others. The geologic, tide, wave, rainfall and wind data were analyzed to determine the causes of this erosion events.

  2. 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. PMID:26056878

  3. Accuracy of Wind Prediction Methods in the California Sea Breeze

    NASA Astrophysics Data System (ADS)

    Sumers, B. D.; Dvorak, M. J.; Ten Hoeve, J. E.; Jacobson, M. Z.

    2010-12-01

    In this study, we investigate the accuracy of measure-correlate-predict (MCP) algorithms and log law/power law scaling using data from two tall towers in coastal environments. We find that MCP algorithms accurately predict sea breeze winds and that log law/power law scaling methods struggle to predict 50-meter wind speeds. MCP methods have received significant attention as the wind industry has grown and the ability to accurately characterize the wind resource has become valuable. These methods are used to produce longer-term wind speed records from short-term measurement campaigns. A correlation is developed between the “target site,” where the developer is interested in building wind turbines, and a “reference site,” where long-term wind data is available. Up to twenty years of prior wind speeds are then are predicted. In this study, two existing MCP methods - linear regression and Mortimer’s method - are applied to predict 50-meter wind speeds at sites in the Salinas Valley and Redwood City, CA. The predictions are then verified with tall tower data. It is found that linear regression is poorly suited to MCP applications as the process produces inaccurate estimates of the cube of the wind speed at 50 meters. Meanwhile, Mortimer’s method, which bins data by direction and speed, is found to accurately predict the cube of the wind speed in both sea breeze and non-sea breeze conditions. We also find that log and power law are unstable predictors of wind speeds. While these methods produced accurate estimates of the average 50-meter wind speed at both sites, they predicted an average cube of the wind speed that was between 1.3 and 1.18 times the observed value. Inspection of time-series error reveals increased error in the mid-afternoon of the summer. This suggests that the cold sea breeze may disrupt the vertical temperature profile, create a stable atmosphere and violate the assumptions that allow log law scaling to work.

  4. 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.

  5. Divergent Skull Morphology Supports Two Trophic Specializations in Otters (Lutrinae)

    PubMed Central

    Timm-Davis, Lori L.; DeWitt, Thomas J.; Marshall, Christopher D.

    2015-01-01

    Variation in terrestrial mammalian skull morphology is known to constrain feeding performance, which in turn influences dietary habits and ultimately fitness. Among mustelids, otters have evolved two feeding specializations: underwater raptorial capture of prey (mouth-oriented) and capture of prey by hand (hand-oriented), both of which have likely associations with morphology and bite performance. However, feeding biomechanics and performance data for otters are sparse. The first goal of this study was to investigate the relationships between feeding morphology and bite performance among two mouth-oriented piscivores (Pteronura brasiliensis and Lontra canadensis) and two hand-oriented invertebrate specialists (Enhydra lutris and Aonyx cinerea). Since other vertebrate taxa that are mouth-oriented piscivores tend to possess longer skulls and mandibles, with jaws designed for increased velocity at the expense of biting capability, we hypothesized that mouth-oriented otters would also possess long, narrow skulls indicative of high velocity jaws. Conversely, hand-oriented otters were expected to possess short, blunt skulls with adaptations to increase bite force and crushing capability. Concomitant with these skull shapes we hypothesized that sea otters would possess a greater mandibular bluntness index, providing for a greater mechanical advantage compared to other otter species investigated. A second goal was to examine morphological variation at a finer scale by assessing variation in cranial morphology among three sea otter subspecies. Since diet varies among these subspecies, and their populations are isolated, we hypothesized that the magnitude of mandibular bluntness and concomitant mechanical advantage, as well as occlusal surface area would also vary within species according to their primary food source (fish versus hard invertebrates). Functional expectations were met for comparisons among and within species. Among species the phylogeny suggests a deeply

  6. Divergent Skull Morphology Supports Two Trophic Specializations in Otters (Lutrinae).

    PubMed

    Timm-Davis, Lori L; DeWitt, Thomas J; Marshall, Christopher D

    2015-01-01

    Variation in terrestrial mammalian skull morphology is known to constrain feeding performance, which in turn influences dietary habits and ultimately fitness. Among mustelids, otters have evolved two feeding specializations: underwater raptorial capture of prey (mouth-oriented) and capture of prey by hand (hand-oriented), both of which have likely associations with morphology and bite performance. However, feeding biomechanics and performance data for otters are sparse. The first goal of this study was to investigate the relationships between feeding morphology and bite performance among two mouth-oriented piscivores (Pteronura brasiliensis and Lontra canadensis) and two hand-oriented invertebrate specialists (Enhydra lutris and Aonyx cinerea). Since other vertebrate taxa that are mouth-oriented piscivores tend to possess longer skulls and mandibles, with jaws designed for increased velocity at the expense of biting capability, we hypothesized that mouth-oriented otters would also possess long, narrow skulls indicative of high velocity jaws. Conversely, hand-oriented otters were expected to possess short, blunt skulls with adaptations to increase bite force and crushing capability. Concomitant with these skull shapes we hypothesized that sea otters would possess a greater mandibular bluntness index, providing for a greater mechanical advantage compared to other otter species investigated. A second goal was to examine morphological variation at a finer scale by assessing variation in cranial morphology among three sea otter subspecies. Since diet varies among these subspecies, and their populations are isolated, we hypothesized that the magnitude of mandibular bluntness and concomitant mechanical advantage, as well as occlusal surface area would also vary within species according to their primary food source (fish versus hard invertebrates). Functional expectations were met for comparisons among and within species. Among species the phylogeny suggests a deeply

  7. Hippocampal neuropathology of domoic acid-induced epilepsy in California sea lions (Zalophus californianus)

    PubMed Central

    Buckmaster, Paul S.; Wen, Xiling; Toyoda, Izumi; Gulland, Frances M. D.; Van Bonn, William

    2014-01-01

    California sea lions (Zalophus californianus) are abundant human-sized carnivores with large gyrencephalic brains. They develop epilepsy after experiencing status epilepticus when naturally exposed to domoic acid. We tested whether sea lions previously exposed to DA (chronic DA sea lions) display hippocampal neuropathology similar to that of human patients with temporal lobe epilepsy. Hippocampi were obtained from control and chronic DA sea lions. Stereology was used to estimate numbers of Nissl-stained neurons per hippocampus in the granule cell layer, hilus, and the pyramidal cell layer of CA3, CA2, and CA1 subfields. Adjacent sections were processed for somatostatin-immunoreactivity or Timm-stained, and the extent of mossy fiber sprouting was measured stereologically. Chronic DA sea lions displayed hippocampal neuron loss in patterns and extents similar but not identical to those reported previously for human patients with temporal lobe epilepsy. Similar to human patients, hippocampal sclerosis in sea lions was unilateral in 79% of cases, mossy fiber sprouting was a common neuropathological abnormality, and somatostatin-immunoreactive axons were exuberant in the dentate gyrus despite loss of immunopositive hilar neurons. Thus, hippocampal neuropathology of chronic DA sea lions is similar to that of human patients with temporal lobe epilepsy. PMID:24638960

  8. Hippocampal neuropathology of domoic acid-induced epilepsy in California sea lions (Zalophus californianus).

    PubMed

    Buckmaster, Paul S; Wen, Xiling; Toyoda, Izumi; Gulland, Frances M D; Van Bonn, William

    2014-05-01

    California sea lions (Zalophus californianus) are abundant human-sized carnivores with large gyrencephalic brains. They develop epilepsy after experiencing status epilepticus when naturally exposed to domoic acid. We tested whether sea lions previously exposed to DA (chronic DA sea lions) display hippocampal neuropathology similar to that of human patients with temporal lobe epilepsy. Hippocampi were obtained from control and chronic DA sea lions. Stereology was used to estimate numbers of Nissl-stained neurons per hippocampus in the granule cell layer, hilus, and pyramidal cell layer of CA3, CA2, and CA1 subfields. Adjacent sections were processed for somatostatin immunoreactivity or Timm-stained, and the extent of mossy fiber sprouting was measured stereologically. Chronic DA sea lions displayed hippocampal neuron loss in patterns and extents similar but not identical to those reported previously for human patients with temporal lobe epilepsy. Similar to human patients, hippocampal sclerosis in sea lions was unilateral in 79% of cases, mossy fiber sprouting was a common neuropathological abnormality, and somatostatin-immunoreactive axons were exuberant in the dentate gyrus despite loss of immunopositive hilar neurons. Thus, hippocampal neuropathology of chronic DA sea lions is similar to that of human patients with temporal lobe epilepsy. PMID:24638960

  9. Evaporation and radiation measurements at Salton Sea, California

    USGS Publications Warehouse

    Sturrock, Alex M.

    1977-01-01

    Evaporation from the Salton Sea, Calif., was computed for a 539-day period between July 14, 1967, and January 2, 1969, by use of energy-budget, mass-transfer, and water budget methods. The total evaporation computed by the three methods agreed within 5 percent. The values of heat transfer to and from the bed were used in the energy-budget computations. Monthly evaporation computed by the energy-budget method for 1968 showed that the Salton Sea exhibited a double wave evaporation similar to that of oceans in the same latitude. Weekly and montly comparisons were made to determine if radiation measured by the flat-plate radiometer is seasonally biased. These comparisons indicate that the measurements of radiation by the flat-plate radiometer are not seasonally biased, and that the Cummings Radiation Integrator gives reliable measurements of radiation for periods as short as 1 week. An empirical mass-transfer coefficient, N, as determined from energy-budget measurements. The value of this coefficient to give evaporation in inches per day is 0.00245 when the windspeed is expressed in miles per hour and the vapor pressure expressed in millibars. (Woodard-USGS)

  10. Chemical evolution of the Salton Sea, California: Nutrient and selenium dynamics

    USGS Publications Warehouse

    Schroeder, R.A.; Orem, W.H.; Kharaka, Y.K.

    2002-01-01

    The Salton Sea is a 1000-km2 terminal lake located in the desert area of southeastern California. This saline (???44 000 mg l-1 dissolved solids) lake started as fresh water in 1905-07 by accidental flooding of the Colorado River, and it is maintained by agricultural runoff of irrigation water diverted from the Colorado River. The Salton Sea and surrounding wetlands have recently acquired substantial ecological importance because of the death of large numbers of birds and fish, and the establishment of a program to restore the health of the Sea. In this report, we present new data on the salinity and concentration of selected chemicals in the Salton Sea water, porewater and sediments, emphasizing the constituents of concern: nutrients (N and P), Se and salinity. Chemical profiles from a Salton Sea core estimated to have a sedimentation rate of 2.3 mm yr-1 show increasing concentrations of OC, N, and P in younger sediment that are believed to reflect increasing eutrophication of the lake. Porewater profiles from two locations in the Sea show that diffusion from bottom sediment is only a minor source of nutrients to the overlying water as compared to irrigation water inputs. Although loss of N and Se by microbial-mediated volatilization is possible, comparison of selected element concentrations in river inputs and water and sediments from the Salton Sea indicates that most of the N (from fertilizer) and virtually all of the Se (delivered in irrigation water from the Colorado River) discharged to the Sea still reside within its bottom sediment. Laboratory simulation on mixtures of sediment and water from the Salton Sea suggest that sediment is a potential source of N and Se to the water column under aerobic conditions. Hence, it is important that any engineered changes made to the Salton Sea for remediation or for transfer of water out of the basin do not result in remobilization of nutrients and Se from the bottom sediment into the overlying water.

  11. 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.

  12. 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

  13. 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. PMID:22091999

  14. Curie Depth Analysis of the Salton Sea Region, Southern California

    NASA Astrophysics Data System (ADS)

    Mickus, Kevin; Hussein, Musa

    2016-02-01

    Aeromagnetic data were analyzed to determine the bottom of magnetic bodies that might be related to the Curie point depth (CPD) by 2D spectral and 3D inversion methods within the Salton Trough and the surrounding region in southern California. The bottom of the magnetic bodies for 55 × 55 km windows varied in depth between 11 and 23 km in depth using 2D spectral methods. Since the 55 × 55 km square window may include both shallow and deep source, a 3D inversion method was used to provide better resolution of the bottom of the magnetic bodies. The 3D models indicate the depth to the bottom of the magnetic bodies varied between 5 and 23 km. Even though both methods produced similar results, the 3D inversion method produced higher resolution of the CPD depths. The shallowest depths (5-8 km) occur along and west of the Brawley Seismic Zone and the southwestern portion of the Imperial Valley. The source of these shallow CPD values may be related to geothermal systems including hydrothermal circulation and/or partially molten material. Additionally, shallow CPD depths (7-12 km) were found in a northwest-trending zone in the center of the Salton Trough. These depths coincide with previous seismic analyses that indicated a lower crustal low velocity region which is believed to be caused by partially molten material. Lower velocity zones in several regions may be related to fracturing and/or hydrothermal fluids. If the majority of these shallow depths are related to temperature, they are likely associated with the CPD, and the partially molten material extends over a wider zone than previously known. Greater depths within the Salton Trough coincide with the base of basaltic material and/or regions of intense metamorphism intruded by mafic material in the middle/lower crust.

  15. 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... Areas Eleventh Coast Guard District § 165.T11-304 Safety zone; Sea World Summer Nights...

  16. Downhole fluid sampling at the SSSDP (Salton Sea Scientific Drilling Project) California State 2-14 well, Salton Sea, California

    SciTech Connect

    Goff, F.; Shevenell, L.; Grigsby, C.O.; Dennis, B.

    1987-07-01

    In situ fluid sampling activities were conducted at the Salton Sea Scientific Drilling Project (SSSDP) well during late December 1985 and late March 1986 to obtain unflashed samples of Salton Sea brine. In late December, three sampling runs were made to depths of approximately 1800 m and temperatures of 300/sup 0/C. In late March, 10 sampling runs were made to depths of approximately 3150 m and temperatures of 350/sup 0/C. In brief, the Los Alamos tool obtained samples from four of eight runs; the Lawrence Berkeley tool obtained samples from one of one run; the Leutert Instruments, Inc., tool obtained samples from zero of three runs; and the USGS quartz crystal experiment was lost in the well. The most complete sample was obtained from run No. 11, using the Los Alamos sampler and Sandia battery pack/controller on a wireline. About 1635 ml of brine, two noble gas samples, and two bulk gas samples were collected from this run. Samples of brine and gas from productive runs have been distributed to about 15 researchers for various types of analyses. Chemical analyses by the Los Alamos and US Geological Survey analytical teams are presented in this report, although they are not corrected for flashing and precipitation.

  17. Rapid behavioural diagnosis of domoic acid toxicosis in California sea lions

    PubMed Central

    Cook, Peter; Reichmuth, Colleen; Gulland, Frances

    2011-01-01

    Domoic acid is a neurotoxic metabolite of widely occurring algal blooms that has caused multiple marine animal stranding events. Exposure to high doses of domoic acid, a glutamate agonist, may lead to persistent medial temporal seizures and damage to the hippocampus. California sea lions (Zalophus californianus) are among the most visible and frequent mammalian victims of domoic acid poisoning, but rapid, reliable diagnosis in a clinical setting has proved difficult owing to the fast clearance of the toxin from the blood stream. Here, we show that the behavioural orienting responses of stranded sea lions diagnosed with domoic acid toxicosis habituate more slowly to a series of non-aversive auditory stimuli than do those of sea lions with no apparent neurological deficits. A signal detection analysis based on these habituation measures was able to correctly identify 50 per cent of subjects with domoic acid toxicosis while correctly rejecting approximately 93 per cent of controls, suggesting potential diagnostic merit. PMID:21389016

  18. Rapid behavioural diagnosis of domoic acid toxicosis in California sea lions.

    PubMed

    Cook, Peter; Reichmuth, Colleen; Gulland, Frances

    2011-08-23

    Domoic acid is a neurotoxic metabolite of widely occurring algal blooms that has caused multiple marine animal stranding events. Exposure to high doses of domoic acid, a glutamate agonist, may lead to persistent medial temporal seizures and damage to the hippocampus. California sea lions (Zalophus californianus) are among the most visible and frequent mammalian victims of domoic acid poisoning, but rapid, reliable diagnosis in a clinical setting has proved difficult owing to the fast clearance of the toxin from the blood stream. Here, we show that the behavioural orienting responses of stranded sea lions diagnosed with domoic acid toxicosis habituate more slowly to a series of non-aversive auditory stimuli than do those of sea lions with no apparent neurological deficits. A signal detection analysis based on these habituation measures was able to correctly identify 50 per cent of subjects with domoic acid toxicosis while correctly rejecting approximately 93 per cent of controls, suggesting potential diagnostic merit. PMID:21389016

  19. 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…

  20. 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. PMID:24048652

  1. 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. PMID:26967136

  2. Underwater psychophysical audiogram of a young male California sea lion (Zalophus californianus).

    PubMed

    Mulsow, Jason; Houser, Dorian S; Finneran, James J

    2012-05-01

    Auditory evoked potential (AEP) data are commonly obtained in air while sea lions are under gas anesthesia; a procedure that precludes the measurement of underwater hearing sensitivity. This is a substantial limitation considering the importance of underwater hearing data in designing criteria aimed at mitigating the effects of anthropogenic noise exposure. To determine if some aspects of underwater hearing sensitivity can be predicted using rapid aerial AEP methods, this study measured underwater psychophysical thresholds for a young male California sea lion (Zalophus californianus) for which previously published aerial AEP thresholds exist. Underwater thresholds were measured in an aboveground pool at frequencies between 1 and 38 kHz. The underwater audiogram was very similar to those previously published for California sea lions, suggesting that the current and previously obtained psychophysical data are representative for this species. The psychophysical and previously measured AEP audiograms were most similar in terms of high-frequency hearing limit (HFHL), although the underwater HFHL was sharper and occurred at a higher frequency. Aerial AEP methods are useful for predicting reductions in the HFHL that are potentially independent of the testing medium, such as those due to age-related sensorineural hearing loss. PMID:22559389

  3. Somatosensory brainstem, thalamus, and cortex of the California sea lion (Zalophus californianus).

    PubMed

    Sawyer, Eva K; Turner, Emily C; Kaas, Jon H

    2016-06-15

    Pinnipeds (sea lions, seals, and walruses) are notable for many reasons, including their ape-sized brains, their adaptation to a coastal niche that combines mastery of the sea with strong ties to land, and the remarkable abilities of their trigeminal whisker system. However, little is known about the central nervous system of pinnipeds. Here we report on the somatosensory areas of the nervous system of the California sea lion (Zalophus californianus). Using stains for Nissl, cytochrome oxidase, and vesicular glutamate transporters, we investigated the primary somatosensory areas in the brainstem, thalamus, and cortex in one sea lion pup and the external anatomy of the brain in a second pup. We find that the sea lion's impressive array of whiskers is matched by a large trigeminal representation in the brainstem with well-defined parcellation that resembles the barrelettes found in rodents but scaled upward in size. The dorsal column nuclei are large and distinct. The ventral posterior nucleus of the thalamus has divisions, with a large area for the presumptive head representation. Primary somatosensory cortex is located in the neocortex just anterior to the main vertical fissure, and precisely locating it as we do here is useful for comparing the highly gyrified pinniped cortex with that of other carnivores. To our knowledge this work is the first comprehensive report on the central nervous system areas for any sensory system in a pinniped. The results may be useful both in the veterinary setting and for comparative studies related to brain evolution. PMID:26878587

  4. Increase California-Oregon Coastal Summer Sea Level Fog from 1950 to 2007

    NASA Astrophysics Data System (ADS)

    Dorman, C. E.

    2015-12-01

    An analysis is presented of the marine fog distribution based upon the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) ship observations taken during 1950-2007. Deep fog occurrence is reported in routine weather reports that are encoded in an ICOADS ship observation. Occurrence is estimated by the number of deep fog observations divided by the total present weather observations in a one-degree area centered on latitude and longitude grid point intersections. The mean fog occurrence for the summer (June-July-August) 1950-2007 was computed for each one degree point. There is a long term, deep fog occurrence maximum on the California-Oregon coast with its highest value of 16.6 % at 38° N 123° W. This fog maximum is coincident with coldest June-July-August sea surface temperatures (SST) along the coast. To compute annual averages of the maximum, a block average was based on the 19 over water grid points with the deep fog occurrences generally greater than 0.6 times the highest long term maximum value that extended along the California-Oregon coast from 37° N to 44° N. The June-July-August block averaged, annual value computed for each of the 58 summers for the period 1950-2007 has a distinct positive trend. A line fitted to the data has a deep fog percent occurrence increase of +7.4 % from 1950 through 2007 or a trend of +0.13 % per year. The Mann-Kendall test was applied and the trend is significant at the 0.05 level. The increase in long term coastal fog is coincident with a decrease in the California-Oregon coastal SST. The SST decrease is consistent with interior California land temperatures increasing, increasing the cross shore sea level pressure gradient, and increasing the along coast winds creating a positive feedback that causes more upwelling and lower SST.

  5. Effects of age, colony, and sex on mercury concentrations in California sea lions

    USGS Publications Warehouse

    McHuron, Elizibeth A; Peterson, Sarah H.; Ackerman, Josh; Melin, Sharon R.; Harris, Jeffrey D.; Costa, Daniel P.

    2016-01-01

    We measured total mercury (THg) concentrations in California sea lions (Zalophus californianus) and examined how concentrations varied with age class, colony, and sex. Because Hg exposure is primarily via diet, we used nitrogen (δ 15N) and carbon (δ 13C) stable isotopes to determine if intraspecific differences in THg concentrations could be explained by feeding ecology. Blood and hair were collected from 21 adult females and 57 juveniles from three colonies in central and southern California (San Nicolas, San Miguel, and Año Nuevo Islands). Total Hg concentrations ranged from 0.01 to 0.31 μg g−1 wet weight (ww) in blood and 0.74 to 21.00 μg g−1 dry weight (dw) in hair. Adult females had greater mean THg concentrations than juveniles in blood (0.15 vs. 0.03 μg−1 ww) and hair (10.10 vs. 3.25 μg−1 dw). Age class differences in THg concentrations did not appear to be driven by trophic level or habitat type because there were no differences in δ 15N or δ 13C values between adults and juveniles. Total Hg concentrations in adult females were 54 % (blood) and 24 % (hair) greater in females from San Miguel than females from San Nicolas Island, which may have been because sea lions from the two islands foraged in different areas. For juveniles, we detected some differences in THg concentrations with colony and sex, although these were likely due to sampling effects and not ecological differences. Overall, THg concentrations in California sea lions were within the range documented for other marine mammals and were generally below toxicity benchmarks for fish-eating wildlife.

  6. Effects of Age, Colony, and Sex on Mercury Concentrations in California Sea Lions.

    PubMed

    McHuron, Elizabeth A; Peterson, Sarah H; Ackerman, Joshua T; Melin, Sharon R; Harris, Jeffrey D; Costa, Daniel P

    2016-01-01

    We measured total mercury (THg) concentrations in California sea lions (Zalophus californianus) and examined how concentrations varied with age class, colony, and sex. Because Hg exposure is primarily via diet, we used nitrogen (δ (15)N) and carbon (δ (13)C) stable isotopes to determine if intraspecific differences in THg concentrations could be explained by feeding ecology. Blood and hair were collected from 21 adult females and 57 juveniles from three colonies in central and southern California (San Nicolas, San Miguel, and Año Nuevo Islands). Total Hg concentrations ranged from 0.01 to 0.31 μg g(-1) wet weight (ww) in blood and 0.74 to 21.00 μg g(-1) dry weight (dw) in hair. Adult females had greater mean THg concentrations than juveniles in blood (0.15 vs. 0.03 μg(-1) ww) and hair (10.10 vs. 3.25 μg(-1) dw). Age class differences in THg concentrations did not appear to be driven by trophic level or habitat type because there were no differences in δ (15)N or δ (13)C values between adults and juveniles. Total Hg concentrations in adult females were 54 % (blood) and 24 % (hair) greater in females from San Miguel than females from San Nicolas Island, which may have been because sea lions from the two islands foraged in different areas. For juveniles, we detected some differences in THg concentrations with colony and sex, although these were likely due to sampling effects and not ecological differences. Overall, THg concentrations in California sea lions were within the range documented for other marine mammals and were generally below toxicity benchmarks for fish-eating wildlife. PMID:26259982

  7. Ectopic pregnancy with associated gestational choriocarcinoma in a California sea lion (Zalophus californianus).

    PubMed

    Fravel, Vanessa A; Lowenstine, Linda J; Koehne, Amanda

    2016-07-01

    A wild-born, captive-reared, 14 yr old, primiparous female California sea lion Zalophus californianus presented for anorexia of 14 d duration and abdominal distention. Routine complete blood cell count revealed leukocytosis with a neutrophilia, and serum chemistry revealed hypoalbumenemia and hyponatremia. Treatment with broad spectrum antibiotics and non-steroidal anti-inflammatories were started, but the animal continued to decline. Abdominal radiographs revealed a mature mineralized fetal skull and spine in the caudal abdomen and abdominal ultrasound revealed ascites but could not confirm the fetus. The patient was taken to surgery where a full term fetus was found outside of the uterus but within the fetal membranes, representing a secondary ectopic pregnancy. The patient passed away during surgery and was taken to necropsy. Gross necropsy revealed a diffuse peritonitis with yellow deposits over the serosal surfaces of the abdominal organs. The uterus appeared intact grossly and the ovaries appeared abnormal. The mesenteric, renal, and sub-lumbar nodes were enlarged and edematous. Histopathology revealed choriocarcinoma in the right uterine horn with evidence of chronic uterine rupture and protrusion of the placental tissue into the abdomen. The choriocarcinoma had metastasized locally as well as to the liver, spleen and lung. Choriocarcinoma is a highly malignant trophoblastic neoplasm that is rare in domestic animals. This case represents, to the authors' knowledge, the first report of gestational choriocarcinoma causing secondary ectopic pregnancy in a California sea lion and presents questions regarding pregnancy monitoring and management in a population of captive, minimally trained California sea lions. PMID:27409239

  8. Occurrence of west nile virus infection in raptors at the Salton Sea, California.

    PubMed

    Dusek, Robert J; Iko, William M; Hofmeister, Erik K

    2010-07-01

    We investigated the prevalence of West Nile virus (WNV)-neutralizing antibodies and infectious virus, and the occurrence of overwinter transmission in two raptor species during January and March 2006 at the Salton Sea, Imperial County, California. We captured 208 American Kestrels (Falco sparverius) (January, n=100; March, n=108) and 116 Burrowing Owls (Athene cunicularia) (January, n=52; March, n=64). Laboratory analysis revealed that 83% of American Kestrels and 31% of Burrowing Owls were positive for WNV-neutralizing antibodies. Additionally, two seroconversions were detected in Burrowing Owls between January and March. Infectious WNV, consistent with acute infection, was not detected in any bird. PMID:20688694

  9. Sea level fluctuations in central California at subtidal to decadal and longer time scales with implications for San Francisco Bay, California

    NASA Astrophysics Data System (ADS)

    Ryan, H. F.; Noble, M. A.

    2007-07-01

    Sea level elevations from near the mouth of San Francisco Bay are used to describe the low-frequency variability of forcing of the coastal ocean on the Bay at a variety of temporal scales. About 90% of subtidal fluctuations in sea level in San Francisco Bay are driven by the sea level variations in the coastal ocean that propagate into the Bay at the estuary mouth. We use the 100-year sea level record available at San Francisco to document a 1.9 mm/yr mean sea level rise, and to determine fluctuations related to El Nino-Southern Oscillation (ENSO) and other climatic events. At time scales greater than 1 year, ENSO dominates the sea level signal and can result in fluctuations in sea level of 10-15 cm. Alongshore wind stress data from central California are also analyzed to determine the impact of changes in coastal elevation at the mouth of San Francisco Bay within the synoptic wind band of 2-30 days. At least 40% of the subtidal fluctuations in sea level of the Bay are tied to the large-scale regional wind field affecting sea level variations in the coastal ocean, with little local, direct wind forcing of the Bay itself. The majority of the subtidal sea level fluctuations within the Bay that are not related to the coastal ocean sea level signal are forced by an east-west sea level gradient resulting from tidally induced variations in sea level at specific beat frequencies that are enhanced in the northern reach of the Bay. River discharge into the Bay through the Sacramento and San Joaquin River Delta also contributes to the east-west gradient, but to a lesser degree.

  10. Sea-Level Rise and Flood Potential along the California Coast

    NASA Astrophysics Data System (ADS)

    Delepine, Q.; Leung, C.

    2013-12-01

    Sea-level rise is becoming an ever-increasing problem in California. Sea-level is expected to rise significantly in the next 100 years, which will raise flood elevations in coastal communities. This will be an issue for private homeowners, businesses, and the state. One study suggests that Venice Beach could lose a total of at least $440 million in tourism spending and tax dollars from flooding and beach erosion if sea level rises 1.4 m by 2100. In addition, several airports, such as San Francisco International Airport, are located in coastal regions that have flooded in the past and will likely be flooded again in the next 30 years, but sea-level rise is expected to worsen the effects of flooding in the coming decades It is vital for coastal communities to understand the risks associated with sea-level rise so that they can plan to adapt to it. By obtaining accurate LiDAR elevation data from the NOAA Digital Coast Website (http://csc.noaa.gov/dataviewer/?keyword=lidar#), we can create flood maps to simulate sea level rise and flooding. The data are uploaded to ArcGIS and contour lines are added for different elevations that represent future coastlines during 100-year flooding. The following variables are used to create the maps: 1. High-resolution land surface elevation data - obtained from NOAA 2. Local mean high water level - from USGS 3. Local 100-year flood water level - from the Pacific Institute 4. Sea-level rise projections for different future dates (2030, 2050, and 2100) - from the National Research Council The values from the last three categories are added to represent sea-level rise plus 100-year flooding. These values are used to make the contour lines that represent the projected flood elevations, which are then exported as KML files, which can be opened in Google Earth. Once these KML files are made available to the public, coastal communities will gain an improved understanding of how flooding and sea-level rise might affect them in the future

  11. Auditory Discrimination of Natural and High-Pass Filtered Bark Vocalizations in a California Sea Lion (Zalophus californianus).

    PubMed

    Mulsow, Jason; Finneran, James J

    2016-01-01

    A California sea lion performed a psychophysical auditory discrimination task with a set of six stimuli: three barks recorded from conspecific males and high-pass filtered versions of the barks that removed the majority of energy at fundamental frequencies. Discrimination performance and subject reaction times (RTs) suggested that the vocalizations were all perceived as fairly dissimilar. This preliminary study hints that low-frequency components are a salient part of the California sea lion bark despite elevation of this species' aerial hearing thresholds and the potential for elevated environmental noise levels at frequencies below 1 kHz. PMID:26611026

  12. Human disturbance influences reproductive success and growth rate in California sea lions (Zalophus californianus).

    PubMed

    French, Susannah S; González-Suárez, Manuela; Young, Julie K; Durham, Susan; Gerber, Leah R

    2011-01-01

    The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups) for California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources). Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations. PMID:21436887

  13. Human Disturbance Influences Reproductive Success and Growth Rate in California Sea Lions (Zalophus californianus)

    PubMed Central

    French, Susannah S.; González-Suárez, Manuela; Young, Julie K.; Durham, Susan; Gerber, Leah R.

    2011-01-01

    The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups) for California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources). Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations. PMID:21436887

  14. Sea Surface Temperature Influence on Terrestrial Gross Primary Production along the Southern California Current.

    PubMed

    Reimer, Janet J; Vargas, Rodrigo; Rivas, David; Gaxiola-Castro, Gilberto; Hernandez-Ayon, J Martin; Lara-Lara, Ruben

    2015-01-01

    Some land and ocean processes are related through connections (and synoptic-scale teleconnections) to the atmosphere. Synoptic-scale atmospheric (El Niño/Southern Oscillation [ENSO], Pacific Decadal Oscillation [PDO], and North Atlantic Oscillation [NAO]) decadal cycles are known to influence the global terrestrial carbon cycle. Potentially, smaller scale land-ocean connections influenced by coastal upwelling (changes in sea surface temperature) may be important for local-to-regional water-limited ecosystems where plants may benefit from air moisture transported from the ocean to terrestrial ecosystems. Here we use satellite-derived observations to test potential connections between changes in sea surface temperature (SST) in regions with strong coastal upwelling and terrestrial gross primary production (GPP) across the Baja California Peninsula. This region is characterized by an arid/semiarid climate along the southern California Current. We found that SST was correlated with the fraction of photosynthetic active radiation (fPAR; as a proxy for GPP) with lags ranging from 0 to 5 months. In contrast ENSO was not as strongly related with fPAR as SST in these coastal ecosystems. Our results show the importance of local-scale changes in SST during upwelling events, to explain the variability in GPP in coastal, water-limited ecosystems. The response of GPP to SST was spatially-dependent: colder SST in the northern areas increased GPP (likely by influencing fog formation), while warmer SST at the southern areas was associated to higher GPP (as SST is in phase with precipitation patterns). Interannual trends in fPAR are also spatially variable along the Baja California Peninsula with increasing secular trends in subtropical regions, decreasing trends in the most arid region, and no trend in the semi-arid regions. These findings suggest that studies and ecosystem process based models should consider the lateral influence of local-scale ocean processes that could

  15. Sea Surface Temperature Influence on Terrestrial Gross Primary Production along the Southern California Current

    PubMed Central

    Reimer, Janet J.; Vargas, Rodrigo; Rivas, David; Gaxiola-Castro, Gilberto; Hernandez-Ayon, J. Martin; Lara-Lara, Ruben

    2015-01-01

    Some land and ocean processes are related through connections (and synoptic-scale teleconnections) to the atmosphere. Synoptic-scale atmospheric (El Niño/Southern Oscillation [ENSO], Pacific Decadal Oscillation [PDO], and North Atlantic Oscillation [NAO]) decadal cycles are known to influence the global terrestrial carbon cycle. Potentially, smaller scale land-ocean connections influenced by coastal upwelling (changes in sea surface temperature) may be important for local-to-regional water-limited ecosystems where plants may benefit from air moisture transported from the ocean to terrestrial ecosystems. Here we use satellite-derived observations to test potential connections between changes in sea surface temperature (SST) in regions with strong coastal upwelling and terrestrial gross primary production (GPP) across the Baja California Peninsula. This region is characterized by an arid/semiarid climate along the southern California Current. We found that SST was correlated with the fraction of photosynthetic active radiation (fPAR; as a proxy for GPP) with lags ranging from 0 to 5 months. In contrast ENSO was not as strongly related with fPAR as SST in these coastal ecosystems. Our results show the importance of local-scale changes in SST during upwelling events, to explain the variability in GPP in coastal, water-limited ecosystems. The response of GPP to SST was spatially-dependent: colder SST in the northern areas increased GPP (likely by influencing fog formation), while warmer SST at the southern areas was associated to higher GPP (as SST is in phase with precipitation patterns). Interannual trends in fPAR are also spatially variable along the Baja California Peninsula with increasing secular trends in subtropical regions, decreasing trends in the most arid region, and no trend in the semi-arid regions. These findings suggest that studies and ecosystem process based models should consider the lateral influence of local-scale ocean processes that could

  16. [Juvenile production of the red sea urchin Strongylocentrotus franciscanus (Echinodermata: Echinoidea) in Baja California, Mexico].

    PubMed

    Salas-Garza, A; Carpizo-Ituarte, E; Parés-Sierra, G; Martínez-López, R; Quintana-Rodríguez, R

    2005-12-01

    The red sea urchin Strongylocentrotusfranciscanus (Agassiz 1863) is harvested commercially in Baja California, Mexico, since 1970; however, in the last ten years the capture per unit effort (CPUE) has decreased from 310 kg/fishing unit/day to 120 kg/fishing unit/day. For this reason, actions were taken to develop a culture technology allowing massive production of juveniles for re-stocking natural populations or for growing them commercially. We summarize some of the basic studies and main achievements in this effort. In Baja California, considerably faster larval development (approximately 21 days) has been attained than in the US northwest coast (62 days). Spawning of red sea urchins was routinely induced with KCI while egg fertilization was performed using a 100,000-sperm/ml solution. Six microalgae species were tested and Rhodomonas sp. produced the best larval development. The mean survival rate at the end of the larval period was 25%, but results varied widely with bactch. From the feed ratios tested, best results were obtained using 7000 cel/ml during the first week of larval development, followed by 10,000 cel/ml during the second and 15,000 cel/ml during the third week. KCl proved the most consistent metamorphic inducer, regularly yielding metamorphosis percentages higher than 90%. Metamorphosis was considered complete when the functional jaw that juveniles use for first benthic feeding appeared (as soon as 20 days after induction). With this method several thousands of red sea urchin juveniles were produced. They reached up to 1.5 mm in size during the first 50 days of culture after metamorphosis, showing the great potential for mass production of this species in the laboratory. PMID:17469265

  17. The epizootiology of type C botulism in fish-eating birds at Salton Sea, California

    USGS Publications Warehouse

    Nol, P.

    2002-01-01

    During 1996, type C avian botulism killed over 15,000 fish-eating birds at the Salton Sea in southern California. Amont those affected were nearly 10,000 western white pelicans (Pelecanus erythrorhynchos) and over 1,200 endangered California brown pelicans (Pelecanus occidentalis californicus). Since 1996, smaller epizootics have occurred every year. Type C botulism is not typically associated with fish-eating birds. In the case of the Salton Sea, Mozambique tilapia (Oreochromis mossambicus) are the suspected source of type C toxin, although the mechanism by which the fish acquire the toxin is still unknown. The goals of this study were to: 1) Determine presence/absence of active Clostridium botulinum type C and type C botulinum toxin in tilapia in the Salton Sea. 2) Use geospatial analyses to evaluate relationships between patterns of mortality in birds and fish and presence/absence of toxin and/or toxin-producing bacteria in sediments and fish. We investigated a method of detecting C. botulinum type C cells in the intestinal contents of Mozambique tilapia. This method involved extraction of predominantly cellular DNA and uses a polymerase chain reaction assay to detect presence of type C toxin gene. We collected sick, dead and healthy fish from various sites throughout the Sea during the summers of 1999 to 2001 in order to test them for the presence of active C. botulinum type C by PCR and for the presence of type C toxin by ELISA and mouse test. The results demonstrate that the tilapia population in the Salton Sea harbors C. botulinum type C cells within their gastrointestinal tract and the prevalence of this organism varies from year to year. The total number of fish with toxin-producing bacteria was significantly greater in 2000 than in 2001. No difference in the numbers of positives was detected between sick and dead fish compared to live fish, and there were no differences noted with regard to location of fish collection. The prevalence of active type C

  18. Sea-surface temperature gradients across blue whale and sea turtle foraging trajectories off the Baja California Peninsula, Mexico

    NASA Astrophysics Data System (ADS)

    Etnoyer, Peter; Canny, David; Mate, Bruce R.; Morgan, Lance E.; Ortega-Ortiz, Joel G.; Nichols, Wallace J.

    2006-02-01

    Sea-surface temperature (SST) fronts are integral to pelagic ecology in the North Pacific Ocean, so it is necessary to understand their character and distribution, and the way these features influence the behavior of endangered and highly migratory species. Here, telemetry data from sixteen satellite-tagged blue whales ( Balaenoptera musculus) and sea turtles ( Caretta caretta, Chelonia mydas, and Lepidochelys olivacea) are employed to characterize 'biologically relevant' SST fronts off Baja California Sur. High residence times are used to identify presumed foraging areas, and SST gradients are calculated across advanced very high resolution radiometer (AVHRR) images of these regions. The resulting values are compared to classic definitions of SST fronts in the oceanographic literature. We find subtle changes in surface temperature (between 0.01 and 0.10 °C/km) across the foraging trajectories, near the lowest end of the oceanographic scale (between 0.03 and 0.3 °C/km), suggesting that edge-detection algorithms using gradient thresholds >0.10 °C/km may overlook pelagic habitats in tropical waters. We use this information to sensitize our edge-detection algorithm, and to identify persistent concentrations of subtle SST fronts in the Northeast Pacific Ocean between 2002 and 2004. The lower-gradient threshold increases the number of fronts detected, revealing more potential habitats in different places than we find with a higher-gradient threshold. This is the expected result, but it confirms that pelagic habitat can be overlooked, and that the temperature gradient parameter is an important one.

  19. Middle Cenozoic depositional, tectonic, and sea level history of southern San Joaquin basin, California

    SciTech Connect

    Decelles, P.G.

    1988-11-01

    As a prolific producer of hydrocarbons, the San Joaquin basin in south-central California has been the subject of geological research since the late nineteenth century. Much of this research has focused on the subsurface Eocene to lower Miocene succession because of its attractive reservoir potential. Although seismic and well-log data are available in profuse quantities, the complex sedimentary architecture of the basin fill, the application of local and inconsistent stratigraphic nomenclature, and the inherent limitations of subsurface data have led to much confusion concerning the middle Cenozoic history of the basin. This paper presents a sedimentological analysis of the depositional systems in the Eocene to lower Miocene strata of the San Emigdio and Tehachapi Mountains. The various depositional systems are considered within the contexts of encompassing depositional sequences to reconstruct the middle Cenozoic depositional, tectonic, and sea level history of the southern San Joaquin basin. 14 figures, 1 table.

  20. Ferrelo fan, California: Depositional system influenced by Eustatic sea level changes

    USGS Publications Warehouse

    Howell, D.G.; Vedder, J.G.

    1984-01-01

    Remnants of an Eocene fan system are preserved onshore at San Diego and in the central part of the southern California borderland. Even though faults and erosion have truncated its margins, geophysical data and exploratory wells indicate that remaining parts of the fan extend beneath an offshore area nearly 400-km long and 40- to 100-km wide. Environments representing fluvial, fan-delta, shelf-channel, overlapping inner- to outer-fan, and basin-plain facies are recognized or inferred. Three progradational cycles onshore and two distinct pulses of sand accumulation offshore are attributable to eustatic low sea-level stands rather than to tectonic uplift or shifts in depositional patterns. ?? 1984 Springer-Verlag New York Inc.

  1. 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

  2. Diagnosing domoic acid toxicosis in the California sea lion (Zalophus californianus) using behavioral criteria: A novel approach.

    PubMed

    Wittmaack, Christiana; Lahvis, Garet P; Keith, Edward O; Self-Sullivan, Caryn

    2015-01-01

    Domoic acid toxicosis in the California sea lion (Zalophus californianus) is difficult to diagnose using presence of toxin alone because the duration of domoic acid presence in blood and urine is generally less than 48 hr following exposure. Because domoic acid toxicosis is often suggested by presentation of behavioral abnormalities, we asked whether assessment of behavior might be useful for diagnostic purposes. We developed an ethogram to categorize behavioral data collected via continuous focal animal sampling. In total, 169 subjects were observed at a rehabilitation center. Sea lions with domoic acid toxicosis displayed head weaving (P < 0.0001) and muscle fasciculations (P < 0.01) significantly more often than animals in a comparison group. Dragging hind flippers and swift scanning were observed exclusively in animals from the domoic acid toxicosis group. The data show that behavioral diagnostic criteria can be effective in the diagnosis of domoic acid toxicosis in the California sea lion. PMID:25962475

  3. Weak Polygyny in California Sea Lions and the Potential for Alternative Mating Tactics

    PubMed Central

    Flatz, Ramona; González-Suárez, Manuela; Young, Julie K.; Hernández-Camacho, Claudia J.; Immel, Aaron J.; Gerber, Leah R.

    2012-01-01

    Female aggregation and male territoriality are considered to be hallmarks of polygynous mating systems. The development of genetic parentage assignment has called into question the accuracy of behavioral traits in predicting true mating systems. In this study we use 14 microsatellite markers to explore the mating system of one of the most behaviorally polygynous species, the California sea lion (Zalophus californianus). We sampled a total of 158 female-pup pairs and 99 territorial males across two breeding rookeries (San Jorge and Los Islotes) in the Gulf of California, Mexico. Fathers could be identified for 30% of pups sampled at San Jorge across three breeding seasons and 15% of sampled pups at Los Islotes across two breeding seasons. Analysis of paternal relatedness between the pups for which no fathers were identified (sampled over four breeding seasons at San Jorge and two at Los Islotes) revealed that few pups were likely to share a father. Thirty-one percent of the sampled males on San Jorge and 15% of the sampled males on Los Islotes were assigned at least one paternity. With one exception, no male was identified as the father of more than two pups. Furthermore, at Los Islotes rookery there were significantly fewer pups assigned paternity than expected given the pool of sampled males (p<0.0001). Overall, we found considerably lower variation in male reproductive success than expected in a species that exhibits behavior associated with strongly polygynous mating. Low variation in male reproductive success may result from heightened mobility among receptive females in the Gulf of California, which reduces the ability of males to monopolize groups of females. Our results raise important questions regarding the adaptive role of territoriality and the potential for alternative mating tactics in this species. PMID:22432039

  4. Equal latency contours for bottlenose dolphins (Tursiops truncatus) and California sea lions (Zalophus californianus).

    PubMed

    Mulsow, Jason; Schlundt, Carolyn E; Brandt, Lacey; Finneran, James J

    2015-11-01

    Loudness perception by non-human animals is difficult to study directly. Previous research efforts have instead focused on estimating loudness perception using simple reaction time (RT) data. These data are used to generate equal latency contours that serve as a proxy for equal loudness contours. To aid the design of auditory weighting functions for marine mammals, equal latency contours were generated using RT data for two marine mammal species that are representative of broader functional hearing groups: the bottlenose dolphin (under water) and California sea lion (in air). In all cases, median RT decreased with increasing tone sound pressure level (SPL). The equal latency contours corresponding to near-threshold SPLs were similar to audiograms for both species. The sea lion contours showed some compression at frequencies below 1 kHz; however, a similar pattern was not apparent in the more variable data for dolphins. Equal latency contours for SPLs greater than approximately 40 dB above threshold diverged from predicted equal loudness contours, likely due to the asymptotic nature of RT at the highest tested SPLs. The results suggest that auditory threshold data, potentially augmented with compression at low frequencies, may provide a useful way forward when designing auditory weighting functions for marine mammals. PMID:26627745

  5. In Utero Domoic Acid Toxicity: A Fetal Basis to Adult Disease in the California Sea Lion (Zalophus californianus)

    PubMed Central

    Ramsdell, John S.; Zabka, Tanja S.

    2008-01-01

    California sea lions have been a repeated subject of investigation for early life toxicity, which has been documented to occur with increasing frequency from late February through mid-May in association with organochlorine (PCB and DDT) poisoning and infectious disease in the 1970’s and domoic acid poisoning in the last decade. The mass early life mortality events result from the concentrated breeding grounds and synchronization of reproduction over a 28 day post partum estrus cycle and 11 month in utero phase. This physiological synchronization is triggered by a decreasing photoperiod of 11.48 h/day that occurs approximately 90 days after conception at the major California breeding grounds. The photoperiod trigger activates implantation of embryos to proceed with development for the next 242 days until birth. Embryonic diapause is a selectable trait thought to optimize timing for food utilization and male migratory patterns; yet from the toxicological perspective presented here also serves to synchronize developmental toxicity of pulsed environmental events such as domoic acid poisoning. Research studies in laboratory animals have defined age-dependent neurotoxic effects during development and windows of susceptibility to domoic acid exposure. This review will evaluate experimental domoic acid neurotoxicity in developing rodents and, aided by comparative allometric projections, will analyze potential prenatal toxicity and exposure susceptibility in the California sea lion. This analysis should provide a useful tool to forecast fetal toxicity and understand the impact of fetal toxicity on adult disease of the California sea lion. PMID:18728728

  6. Body and Surface-wave ambient noise seismic interferometry in the Salton Sea Geothermal Field, California

    NASA Astrophysics Data System (ADS)

    Sabey, L.; Hole, J. A.; Han, L.; Stock, J. M.; Fuis, G. S.

    2013-12-01

    Seismic reflection and refraction data were acquired as a part of the Salton Seismic Imaging Project in March 2011. Alongside traditional explosive source recording, a dense array of 486 seismometers across the Salton Sea Geothermal Field and Brawley Seismic Zone recorded 135 hours of natural noise sources. The geothermal field is located within the Imperial Valley in Southern California and is bordered by the southern end of the Salton Sea. There is abundant microseismicity recorded in the area, including over 100-recorded earthquakes, wave action, geothermal pumping operations, a railroad, and two highways. Volcanism associated with rifting processes provides a prolific heat source to the system marking the Salton Sea Geothermal Field as one of the largest and hottest geothermal fields in California. Seismic interferometry is a technique that uses continuous recordings of natural noise to create a 'virtual source' by cross-correlation of receiver pairs followed by stacking. This method has been highly successful for surface waves and a few previous studies have shown evidence of body waves and reflections. As anticipated the abundant tectonic and induced noise sources within our study area produced visible surface and body waves. Inclusion of the earthquakes with normalized amplitudes improved overall data quality. The virtual shots from our data our compare well to our twelve explosive shots at near offsets. The highest quality virtual source gathers are produced near anthropogenic noise sources. In particular, one large geothermal plant acted as a sufficiently strong point source producing a gather similar to what we would see from an explosive source. Surface waves recorded on 4.5-Hz geophones were retrievable from 1-6Hz after cross-correlation and stacking. Up to 30km of body waves were also observed in the 25-30Hz range. Future studies will include surface wave dispersion analysis and attempt body wave reflection imaging. The 100-meter spacing of our

  7. 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

  8. Effects of carbon dioxide sequestration on California margin deep-sea foraminiferal assemblages

    SciTech Connect

    Ricketts, Erin R.; Kennett, James P.; Hill, Tessa M.; Barry, James P.

    2009-09-01

    Abstract Deep-sea sequestration of CO2 is being considered as a possible mitigation tool to decrease atmospheric CO2 concentrations and its associated negative effects. This study investigated potential effects of liquid carbon dioxide (CO2) injection on deep-sea foraminiferal assemblages. Foraminifera are ideal for this ecological impact investigation because of differing test composition (calcareous and non-calcareous) and thickness, and diverse epifaunal and infaunal depth preferences. The experiment was conducted on August-September 2003, at 3600 m off the coast of Monterey Bay, California, aboard the R/V Western Flyer using the ROV Tiburon. The pH of the site was monitored throughout the experiment. Sediment push-cores were collected (both from the experimental and control sites) and stained to distinguish live (stained) from dead (unstained) individuals. Effects of CO2 injection on assemblages have been tracked both vertically (to 10 cm depth below sea floor) and horizontally (up to 10 m from CO2 injection sites), as well as between live and dead individuals. Within corrals (containing the injected CO2) and their underlying sediments, severe pH changes (near 4.0 units) were recorded. This compares with a record of small average reductions in ocean pH (-0.05 units) combined with large episodic excursions (-1.7 units) over the experimental area due to the injection of CO2. Exposure to this gradient of low pH caused increased mortality and dissolution of calcareous forms within corrals, as far as 5 m from the injection site, and to at least 10 cm depth in the sediments. This experiment revealed several major effects of CO2 injection on foraminiferal assemblages in surficial sediments: 1) total number of foraminifera in a sample decreases; 2) foraminiferal species richness decreases in both stained and unstained specimens; and 3) relative percentage of stained (live) forms in the remaining tests increases. Down-core trends (to 10 cm below sea floor) have revealed

  9. 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.

  10. 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. PMID:27010261

  11. California sea mussel and bay mussel: Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest)

    SciTech Connect

    Shaw, W.N.; Hassler, T.J.; Moran, D.P.

    1988-09-01

    Species profiles are literature summaries of the taxonomy, morphology, distribution, life history, and environmental requirements of coastal aquatic species. They are prepared to assist in environmental impact assessment. The California sea mussel, Mytilus californianus, and the bay mussel, M. edulis, are commonly collected for bait. Some commercial landing and aquaculture occurs at a very low level of production. Both species are distributed along the California coast; the sea mussel is more commonly found on intertidal coastal rocks and the bay mussel on pilings and other hard substrates in bays and estuaries. The eggs of both species develop into a trochophore stage in 12--24 hours after fertilization, and the planktonic larval stage lasts 3--4 weeks. Sexual maturity can occur in one year. Spawning of the sea mussel occurs sporadically throughout the year; the bay mussel spawns in central California in late fall and winter. Maximum length is 120--150 mm for the bay mussel and 200--250 mm for the sea mussel. Both species are regarded as unsafe to eat from May 1 to October 31 due to the possible presence of paralytic shellfish poisoning. 55 refs., 4 figs., 5 tabs.

  12. 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

  13. Technical report: Marine mammals study number 6. Mortality of sea otter weanlings in eastern and western Prince William Sound, Alaska during the winter of 1990-91. Marine mammal study 6-18. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Rotterman, L.M.; Monnett, C.

    1995-05-01

    Sixty-four dependent sea otters Eastern Prince William Sound (EPWS): n = 24; Western Prince William Sound (WPWS), the oil spill area: n = 401 were captured, examined, instrumented with radio-transmitters, and monitored in Prince William Sound between September 1990 and July 15, 1991. While the absolute timing of instrumentation was similar for pups in EPWS and the oil spill area, pups in the oil spill area weighed significantly less at the time of capture than their counterparts in EPWS. Most pups in EPWS became independent of their mothers in October, whereas mother-pup separation typically occurred in November and December in the oil spill area. Most mortality in EPWS occurred during November and December of 1990, whereas most mortality in the oil spill area occurred during January 1991. Survival rates of weanlings over their first winter (analyses consider data until May 1, 1991) were significantly higher in EPWS (the control) than in the oil spill region.

  14. Hydrocarbons in hair, livers and intestines of sea otters (`enhydra lutris`) found dead along the path of the Exxon Valdez oil spill. Marine mammal study 6-3. Exxon Valdez oil spill state/federal natural resource damage assessment. Final report

    SciTech Connect

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

    1997-05-01

    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, suggesting that uptake into the tissues was limited, or that hydrocarbons within the tissues had been metabolized by the time samples were collected.

  15. Molecular Epidemiology of Cryptosporidium spp. and Giardia spp. in Mussels (Mytilus californianus) and California Sea Lions (Zalophus californianus) from Central California

    PubMed Central

    Adell, A. D.; Shapiro, K.; Melli, A.; Conrad, P. A.

    2014-01-01

    Cryptosporidium and Giardia are of public health importance, with recognized transmission through recreational waters. Therefore, both can contaminate marine waters and shellfish, with potential to infect marine mammals in nearshore ecosystems. A 2-year study was conducted to evaluate the presence of Cryptosporidium and Giardia in mussels located at two distinct coastal areas in California, namely, (i) land runoff plume sites and (ii) locations near sea lion haul-out sites, as well as in feces of California sea lions (CSL) (Zalophus californianus) by the use of direct fluorescent antibody (DFA) detection methods and PCR with sequence analysis. In this study, 961 individual mussel hemolymph samples, 54 aliquots of pooled mussel tissue, and 303 CSL fecal samples were screened. Giardia duodenalis assemblages B and D were detected in hemolymph from mussels collected near two land runoff plume sites (Santa Rosa Creek and Carmel River), and assemblages C and D were detected in hemolymph from mussels collected near a sea lion haul-out site (White Rock). These results suggest that mussels are being contaminated by protozoa carried in terrestrial runoff and/or shed in the feces of CSL. Furthermore, low numbers of oocysts and cysts morphologically similar to Cryptosporidium and Giardia, respectively, were detected in CSL fecal samples, suggesting that CSL could be a source and a host of protozoan parasites in coastal environments. The results of this study showed that Cryptosporidium and Giardia spp. from the feces of terrestrial animals and CSL can contaminate mussels and coastal environments. PMID:25281384

  16. Molecular epidemiology of Cryptosporidium spp. and Giardia spp. in mussels (Mytilus californianus) and California sea lions (Zalophus californianus) from Central California.

    PubMed

    Adell, A D; Smith, W A; Shapiro, K; Melli, A; Conrad, P A

    2014-12-01

    Cryptosporidium and Giardia are of public health importance, with recognized transmission through recreational waters. Therefore, both can contaminate marine waters and shellfish, with potential to infect marine mammals in nearshore ecosystems. A 2-year study was conducted to evaluate the presence of Cryptosporidium and Giardia in mussels located at two distinct coastal areas in California, namely, (i) land runoff plume sites and (ii) locations near sea lion haul-out sites, as well as in feces of California sea lions (CSL) (Zalophus californianus) by the use of direct fluorescent antibody (DFA) detection methods and PCR with sequence analysis. In this study, 961 individual mussel hemolymph samples, 54 aliquots of pooled mussel tissue, and 303 CSL fecal samples were screened. Giardia duodenalis assemblages B and D were detected in hemolymph from mussels collected near two land runoff plume sites (Santa Rosa Creek and Carmel River), and assemblages C and D were detected in hemolymph from mussels collected near a sea lion haul-out site (White Rock). These results suggest that mussels are being contaminated by protozoa carried in terrestrial runoff and/or shed in the feces of CSL. Furthermore, low numbers of oocysts and cysts morphologically similar to Cryptosporidium and Giardia, respectively, were detected in CSL fecal samples, suggesting that CSL could be a source and a host of protozoan parasites in coastal environments. The results of this study showed that Cryptosporidium and Giardia spp. from the feces of terrestrial animals and CSL can contaminate mussels and coastal environments. PMID:25281384

  17. Gas Bubble Disease in the Brain of a Living California Sea Lion (Zalophus californianus)

    PubMed Central

    Van Bonn, William; Dennison, Sophie; Cook, Peter; Fahlman, Andreas

    2013-01-01

    A yearling California sea lion (Zalophus californianus) was admitted into rehabilitation with signs of cerebellar pathology. Diagnostic imaging that included radiography and magnetic resonance imaging (MRI) demonstrated space-occupying lesions predominantly in the cerebellum that were filled partially by CSF-like fluid and partially by gas, and cerebral lesions that were fluid filled. Over a maximum period of 4 months, the brain lesions reduced in size and the gas resorbed and was replaced by CSF-like fluid. In humans, the cerebellum is known to be essential for automating practiced movement patterns (e.g., learning to touch-type), also known as procedural learning or the consolidation of “motor memory.” To test the animal in this study for motor memory deficits, an alternation task in a two-choice maze was utilized. The sea lion performed poorly similar to another case of pneumocerebellum previously reported, and contrary to data acquired from a group of sea lions with specific hippocampal injury. The learning deficits were attributed to the cerebellar injury. These data provide important insight both to the clinical presentation and behavioral observations of cerebellar injury in sea lions, as well as providing an initial model for long-term outcome following cerebellar injury. The specific etiology of the gas could not be determined. The live status of the patient with recovery suggests that the most likely etiologies for the gas are either de novo formation or air emboli secondary to trauma. A small air gun pellet was present within and was removed from soft tissues adjacent to the tympanic bulla. While no evidence to support the pellet striking bone was found, altered dive pattern associated with this human interaction may have provided the opportunity for gas bubble formation to occur. The similarity in distribution of the gas bubble related lesions in this case compared with another previously published case of pneumocerebellum suggests that

  18. The Effects of Carbon Dioxide Sequestration on Deep-sea Foraminifera in two California Margin Experiments

    SciTech Connect

    Ricketts, Erin R

    2006-01-01

    ABSTRACT Deep-sea sequestration of CO2 is being considered as a possible mitigation tool to decrease atmospheric CO2 concentrations and its associated negative effects. This study is the first to investigate potential effects of liquid carbon dioxide (CO2) injection on deep-sea foraminiferal assemblages. Foraminifera are ideal for this ecological impact investigation because of differing test composition (calcareous and non-calcareous) and thickness, and diverse epifaunal and infaunal depth preferences. The experiment was conducted August-September 2003, at 3600m off the coast of Monterey Bay, California, aboard the R/V Western Flyer using the ROV Tiburon. The pH of the site was monitored throughout the experiment by Seabird CTDs. Sediment push-cores were collected (both from the experimental and control sites) and stained to distinguish live (stained) from dead (unstained) individuals. Effects of CO2 injection on assemblages have been tracked both vertically (to 10cm depth below sea floor) and horizontally (up to 10m from CO2 injection sites), as well as between live and dead individuals. Within the corrals and underlying sediments severe pH changes (to near 4.0) were seen while over the experimental area small average reductions in ocean pH (-0.05 units) and large episodic excursions (-1.7 units) were measured resulting from CO2 injection. Exposure to this gradient of low pH caused increased mortality and dissolution of calcareous forms within corrals, as far as 5m from the injection site, and to at least 10cm depth in the sediments. This experiment revealed several major effects of CO2 injection on foraminiferal assemblages in surficial sediments: 1) total number of foraminifera in a sample decreases; 2) foraminiferal species richness decreases in both stained and unstained specimens; and 3) percentage of stained (live) forms increases. Down-core trends (to 10cm below sea floor) have revealed: 1) percent agglutinated forms decline and calcareous forms increase

  19. Last interglacial sea-surface temperature estimates from the California margin; improvements to the modern analog technique

    USGS Publications Warehouse

    Dowsett, Harry J.; Poore, Richard Z.

    1999-01-01

    Total faunal analyses of planktic foraminifer assemblages are used to derive sea surface temperature estimates for the last interglacial from Ocean Drilling Program Sites 1018 and 1020 off northern and central California. Foraminifer assemblage data were transformed to sea-surface temperature (SST) estimates by using the modern analog technique (MAT). In order to improve our ability to estimate SST in this area, the coretop calibration data base used in the MAT was augmented by 13 new age-validated coretop assemblages from the U.S. Pacific Margin.

  20. 75 FR 62445 - Otter Tail Valley Railroad Company, Inc.-Abandonment Exemption-in Otter Tail County, MN

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-08

    ... Surface Transportation Board Otter Tail Valley Railroad Company, Inc.-Abandonment Exemption-- in Otter Tail County, MN Otter Tail Valley Railroad Company, Inc. (OTVR) filed a verified notice of exemption... milepost 48.422 near Fergus Falls, and milepost 47.60 near Hoot Lake, in Otter Tail County, Minn.\\1\\...

  1. Molecular Markers, MAT and Modeling: New Evidence for Leptospirosis Being Endemic in California Sea Lions, with Periodic Epizootics that Defy the Host-adapted Strain Paradigm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leptospirosis is a zoonotic disease infecting a broad range of mammalian hosts, and is re-emerging globally in humans and domestic dogs. Disease outbreaks have occurred periodically in California sea lions (Zalophus californianus) off the central and northern coasts of California, with hundreds of a...

  2. Persistent marine debris in the North Sea, Northwest Atlantic Ocean, Wider Caribbean Area, and the West Coast of Baja California. Final report

    SciTech Connect

    Heneman, B.

    1988-07-01

    Information on persistent marine debris (including plastics, glass, metal, and tar) in four study areas (North Sea, northwest Atlantic Ocean, Wider Caribbean Area, and the west coast of Baja California) was obtained through literature searches, a mailed survey, correspondence, interviews, and personal observations. All of the study areas except Baja California were found to have severe marine debris problems.

  3. Selenium in aquatic biota inhabiting agricultural drains in the Salton Sea Basin, California.

    PubMed

    Saiki, Michael K; Martin, Barbara A; May, Thomas W

    2012-09-01

    Resource managers are concerned that water conservation practices in irrigated farmlands along the southern border of the Salton Sea, Imperial County, California, could increase selenium concentrations in agricultural drainwater and harm the desert pupfish (Cyprinodon macularius), a federally protected endangered species. As part of a broader attempt to address this concern, we conducted a 3-year investigation to collect baseline information on selenium concentrations in seven agricultural drains inhabited by pupfish. We collected water, sediment, selected aquatic food-chain taxa (particulate organic detritus, filamentous algae, net plankton, and midge [Chironomidae] larvae), and two poeciliid fishes (western mosquitofish Gambusia affinis and sailfin molly Poecilia latipinna) for selenium determinations. The two fish species served as ecological surrogates for pupfish, which we were not permitted to sacrifice. Dissolved selenium ranged from 0.70 to 32.8 μg/L, with selenate as the major constituent. Total selenium concentrations in other environmental matrices varied widely among drains, with one drain (Trifolium 18) exhibiting especially high concentrations in detritus, 5.98-58.0 μg Se/g; midge larvae, 12.7-50.6 μg Se/g; mosquitofish, 13.2-20.2 μg Se/g; and mollies, 12.8-30.4 μg Se/g (all tissue concentrations are based on dry weights). Although toxic thresholds for selenium in fishes from the Salton Sea are still poorly understood, available evidence suggests that ambient concentrations of this element may not be sufficiently elevated to adversely affect reproductive success and survival in selenium-tolerant poeciliids and pupfish. PMID:21915593

  4. INTRAPERITONEAL DEXTROSE ADMINISTRATION AS AN ALTERNATIVE EMERGENCY TREATMENT FOR HYPOGLYCEMIC YEARLING CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS).

    PubMed

    Fravel, Vanessa A; Van Bonn, William; Gulland, Frances; Rios, Carlos; Fahlman, Andreas; Graham, James L; Havel, Peter J

    2016-03-01

    The Marine Mammal Center (TMMC) cares for malnourished California sea lion (CSL) (Zalophus californianus) pups and yearlings every year. Hypoglycemia is a common consequence of malnutrition in young CSLs. Administering dextrose during a hypoglycemic crisis is vital to recovery. Traditional veterinary approaches to treat hypoglycemia pose therapeutic challenges in otariids, as vascular access and catheter maintenance can be difficult. The current approach to a hypoglycemic episode at TMMC is to administer dextrose intravenously (i.v.) by medically trained personnel. Intraperitoneal (i.p.) dextrose administration is an attractive alternative to i.v. administration because volunteer staff with basic training can administer treatment instead of waiting for trained staff to treat. This study compares the effects of i.v., i.p., and no dextrose administration on serum glucose and insulin in clinically healthy, euglycemic CSL yearlings. Three groups of animals, consisting of five sea lions each, were treated with 500 mg/kg dextrose using one of the following routes: i.v., i.p., or no dextrose (control). A jugular catheter was placed, and blood samples were collected at times 0, 5, 15, 30, 60, 120, 180, and 240 min after dextrose administration. I.v. dextrose administration resulted in an increase of serum glucose concentrations from a baseline level of approximately 150 mg/dl to a peak of approximately 350 mg/dl. The resulting hyperglycemia persisted for approximately 2 hr and was associated with an attenuated plasma insulin response compared with most terrestrial mammals. Intraperitoneal dextrose administration resulted in increases of serum glucose to approximately 200 mg/dl, which gradually declined to baseline by 2 hr after dextrose administration. These data suggest that the initial treatment of a hypoglycemic crisis in young malnourished CSLs can be accomplished with i.p. dextrose, thus enabling minimally trained volunteer staff to respond immediately to a crisis

  5. 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

  6. 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. PMID:26056370

  7. Atmospheric dry deposition in the vicinity of the Salton Sea, California - I: Air pollution and deposition in a desert environment

    USGS Publications Warehouse

    Alonso, R.; Bytnerowicz, A.; Boarman, W.I.

    2005-01-01

    Air pollutant concentrations and atmospheric dry deposition were monitored seasonally at the Salton Sea, southern California. Measurements of ozone (O 3), nitric acid vapor (HNO3), ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO 2) were performed using passive samplers. Deposition rates of NO 3-, NH4+, Cl-, SO 42-, Na+, K+ and Ca2+ to creosote bush branches and nylon filters as surrogate surfaces were determined for one-week long exposure periods. Maximum O3 values were recorded in spring with 24-h average values of 108.8 ??g m-3. Concentrations of NO and NO2 were low and within ranges of the non-urban areas in California (0.4-5.6 and 3.3-16.2 ??g m-3 ranges, respectively). Concentrations of HNO3 (2.0-6.7 ??g m-3) and NH 3 (6.4-15.7 ??g m-3) were elevated and above the levels typical for remote locations in California. Deposition rates of Cl-, SO42-, Na+, K+ and Ca2+ were related to the influence of sea spray or to suspended soil particles, and no strong enrichments caused by ions originated by human activities were detected. Dry deposition rates of NO3- and NH4+ were similar to values registered in areas where symptoms of nitrogen saturation and changes in species composition have been described. Deposition of nitrogenous compounds might be contributing to eutrophication processes at the Salton Sea. ?? 2005 Elsevier Ltd. All rights reserved.

  8. The cost of male aggression and polygyny in California sea lions (Zalophus californianus).

    PubMed

    Gerber, Leah R; González-Suárez, Manuela; Hernández-Camacho, Claudia J; Young, Julie K; Sabo, John L

    2010-01-01

    In polygynous mating systems, males often increase their fecundity via aggressive defense of mates and/or resources necessary for successful mating. Here we show that both male and female reproductive behavior during the breeding season (June-August) affect female fecundity, a vital rate that is an important determinant of population growth rate and viability. By using 4 years of data on behavior and demography of California sea lions (Zalophus californianus), we found that male behavior and spatial dynamics--aggression and territory size--are significantly related to female fecundity. Higher rates of male aggression and larger territory sizes were associated with lower estimates of female fecundity within the same year. Female aggression was significantly and positively related to fecundity both within the same year as the behavior was measured and in the following year. These results indicate that while male aggression and defense of territories may increase male fecundity, such interactions may cause a reduction in the overall population growth rate by lowering female fecundity. Females may attempt to offset male-related reductions in female fecundity by increasing their own aggression-perhaps to defend pups from incidental injury or mortality. Thus in polygynous mating systems, male aggression may increase male fitness at the cost of female fitness and overall population viability. PMID:20808931

  9. Evidence for a genetic basis of urogenital carcinoma in the wild California sea lion.

    PubMed

    Browning, Helen M; Acevedo-Whitehouse, Karina; Gulland, Frances M D; Hall, Ailsa J; Finlayson, Jeanie; Dagleish, Mark P; Billington, Karen J; Colegrove, Kathleen; Hammond, John A

    2014-12-01

    Although neoplasia is a major cause of mortality in humans and domestic animals, it has rarely been described in wildlife species. One of the few examples is a highly prevalent urogenital carcinoma in California sea lions (CSLs). Although the aetiology of this carcinoma is clearly multifactorial, inbreeding depression, as estimated using levels of microsatellite multilocus heterozygosity, is identified as predictive for this neoplasia. On further analysis, this relationship appears to be largely driven by one marker, suggesting that a single locus might be associated with the occurrence of this disease in CSLs. In a case-control study, carcinoma was significantly associated with homozygosity at the Pv11 microsatellite locus. Pv11 was mapped to intron 9 of the heparanase 2 gene (HPSE2) locus, a very large gene encoding heparanase 2, which in humans is associated with multiple carcinomas. Correspondingly, immunohistochemical labelling in tissues was present in carcinoma cases within a single homozygous Pv11 genotype. To our knowledge, this is the first report of an individual locus being associated with cancer in any wildlife species. This adds emphasis to the study of HPSE2 in other species, including humans and will guide future studies on this sentinel species that shares much of its diet and environment with humans. PMID:25339718

  10. Evidence for a genetic basis of urogenital carcinoma in the wild California sea lion

    PubMed Central

    Browning, Helen M.; Acevedo-Whitehouse, Karina; Gulland, Frances M. D.; Hall, Ailsa J.; Finlayson, Jeanie; Dagleish, Mark P.; Billington, Karen J.; Colegrove, Kathleen; Hammond, John A.

    2014-01-01

    Although neoplasia is a major cause of mortality in humans and domestic animals, it has rarely been described in wildlife species. One of the few examples is a highly prevalent urogenital carcinoma in California sea lions (CSLs). Although the aetiology of this carcinoma is clearly multifactorial, inbreeding depression, as estimated using levels of microsatellite multilocus heterozygosity, is identified as predictive for this neoplasia. On further analysis, this relationship appears to be largely driven by one marker, suggesting that a single locus might be associated with the occurrence of this disease in CSLs. In a case–control study, carcinoma was significantly associated with homozygosity at the Pv11 microsatellite locus. Pv11 was mapped to intron 9 of the heparanase 2 gene (HPSE2) locus, a very large gene encoding heparanase 2, which in humans is associated with multiple carcinomas. Correspondingly, immunohistochemical labelling in tissues was present in carcinoma cases within a single homozygous Pv11 genotype. To our knowledge, this is the first report of an individual locus being associated with cancer in any wildlife species. This adds emphasis to the study of HPSE2 in other species, including humans and will guide future studies on this sentinel species that shares much of its diet and environment with humans PMID:25339718

  11. The Cost of Male Aggression and Polygyny in California Sea Lions (Zalophus californianus)

    PubMed Central

    Gerber, Leah R.; González-Suárez, Manuela; Hernández-Camacho, Claudia J.; Young, Julie K.; Sabo, John L.

    2010-01-01

    In polygynous mating systems, males often increase their fecundity via aggressive defense of mates and/or resources necessary for successful mating. Here we show that both male and female reproductive behavior during the breeding season (June–August) affect female fecundity, a vital rate that is an important determinant of population growth rate and viability. By using 4 years of data on behavior and demography of California sea lions (Zalophus californianus), we found that male behavior and spatial dynamics—aggression and territory size—are significantly related to female fecundity. Higher rates of male aggression and larger territory sizes were associated with lower estimates of female fecundity within the same year. Female aggression was significantly and positively related to fecundity both within the same year as the behavior was measured and in the following year. These results indicate that while male aggression and defense of territories may increase male fecundity, such interactions may cause a reduction in the overall population growth rate by lowering female fecundity. Females may attempt to offset male-related reductions in female fecundity by increasing their own aggression—perhaps to defend pups from incidental injury or mortality. Thus in polygynous mating systems, male aggression may increase male fitness at the cost of female fitness and overall population viability. PMID:20808931

  12. Systemic mycosis in a California sea lion (Zalophus californianus) with detection of cystofilobasidiales DNA.

    PubMed

    Field, Cara L; Tuttle, Allison D; Sidor, Inga F; Nyaoke, Akinyi; Deering, Kathleen M; Gilbert-Marcheterre, Kelly; Risatti, Guillermo; Spoon, Tracey; Meegan, Jenny; Romano, Tracy A; Frasca, Salvatore; Dunn, J Lawrence

    2012-03-01

    A 6-yr-old, intact male California sea lion (Zalophus californianus) with a systemic mycosis died after 5 wk of antifungal drug therapy. Antemortem clinical findings included hind flipper swelling, ring-lesions on skin of the flippers, and dermal nodules that increased in size and number spreading from the hind flippers and ventral abdomen to the foreflippers and muzzle. Lesions were accompanied by severe lymphadenopathy and development of systemic clinical signs despite therapy using itraconazole and later voriconazole. Histopathologic evaluation of biopsies revealed granulomatous dermatitis due to infection by fungus-producing yeast cells in tissue. Isolation attempts, using biopsied skin and tissue samples collected at necropsy, failed to yield growth of a fungus producing yeast cells like those in histologic section. Consensus polymerase chain reaction (PCR) tests of biopsied skin for fungal DNA produced an amplicon having significant sequence identity with a Cystofilobasidiales, a fungus belonging to a subclade that includes several Cryptococcus spp. Histopathologic evaluation of necropsy tissues revealed a systemic mycosis with yeast cells disseminated throughout subcutis, lymph nodes, and viscera. Hepatic necrosis was identified associated with acute liver failure, possibly from the voriconazole administration. This is the first report documenting the clinical presentation, treatment, and pathologic findings of infection associated with Cystofilobasidiales in a marine mammal and serves to expand the understanding of mycoses in pinnipeds. PMID:22448522

  13. Application of high-resolution thermal infrared sensors for geothermal exploration at the Salton Sea, California

    NASA Astrophysics Data System (ADS)

    Reath, K. A.; Ramsey, M.; Tratt, D. M.

    2010-12-01

    The Salton Sea geothermal field straddles the southeast margin of the Salton Sea in California, USA. This field includes approximately 20km2 of mud volcanoes and mud pots and centered on the Mullet Island thermal anomaly. The area has been previously exploited for geothermal power; there are currently seven power plants in the area that produce 1000 MW. The field itself is relatively un-vegetated, which provides for unfettered detection of the surface mineralogy, radiant heat, and emitted gases using air and spaceborne thermal infrared (TIR) sensors. On March 26, 2009, the airborne Spatially Enhanced Broadband Array Spectrograph System (SEBASS) sensor was flown over the Salton Sea-Mullet Island area. SEBASS has a spectral resolution of 128 bands in the 7.5-14.5 micron spectral region and a spatial resolution of 1m/pixel from the 3000-ft altitude flown for this study. A large portion of the Calipatria Fault, a NW/SE-trending geothermally active fault that bisects the Mullet Island thermal anomaly, was imaged during this flight and several thermal/mineralogical anomalies were noted. The orbital Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) has only 5 spectral bands at 90m/pixel resolution, but has acquired dozens of visible and TIR datasets over the geothermal field in the 10-year history of the instrument. The thermal-temporal trend of this dataset has been analyzed, and the November 2008 image studied in detail for comparison to SEBASS. The land-leaving TIR radiance data were separated into brightness temperature and surface emissivity. TIR emissivity data are unique to each mineral and a TIR mineral spectral library was used to determine their presence on the ground. Various mineral maps were created showing the distribution surrounding the most active geothermal features. The higher spectral/spatial resolution SEBASS data were used to validate the lower spectral/spatial resolution ASTER data (as well as the higher resolution laboratory TIR

  14. DETERMINATION OF A SEDATIVE PROTOCOL FOR USE IN CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS) WITH NEUROLOGIC ABNORMALITIES UNDERGOING ELECTROENCEPHALOGRAPHIC EXAMINATION

    PubMed Central

    Dennison, Sophie; Haulena, Martin; Williams, D. Colette; Dawson, John; Yandell, Brian S.; Gulland, Frances M. D.

    2010-01-01

    Sedation in sea lions exhibiting abnormal neurologic signs may require modification of established sedation protocols because of the likely interaction between effects of the sedative and physiologic changes in diseased animals. The effects of two sedative combinations, 0.07 mg/kg medetomidine and 0.07 mg/kg medetomidine plus 0.2 mg/kg butorphanol, were compared between California sea lions (Zalophus californianus) with signs of neurologic dysfunction (n = 33) and without neurologic signs (n = 8). Sedation depth was scored on a scale of 0 (no effect) to 4 (profound sedation) assessed by response to auditory, tactile, and visual stimuli at the time of perceived maximal sedative effect. In the medetomidine-alone group, sea lions with neurologic signs attained a median sedation score of 4 compared to a median sedation score of 1 in the clinically normal sea lions. Sea lions with and without neurologic signs given medetomidine–butorphanol attained a median sedation score of 4. No statistically significant difference in time to induction and respiratory rate was found between the two sedation protocols in all sea lions. In the sea lions with neurologic signs, the recovery time from medetomidine–butorphanol sedation was prolonged (P < 0.01) and minimum recorded heart rates, although remaining within normal physiologic limits, were lower (P = 0.02) when compared to the sea lions administered medetomidine alone. Muscle jerks were observed in many animals given medetomidine–butorphanol and were detrimental to the diagnostic quality of the electroencephalogram (EEG) recording. Medetomidine alone at a dose rate of 0.07 mg/kg thus provides adequate and safe sedation in sea lions with neurologic signs undergoing EEG evaluation. PMID:19110694

  15. Determination of a sedative protocol for use in California sea lions (Zalophus californianus) with neurologic abnormalities undergoing electroencephalographic examination.

    PubMed

    Dennison, Sophie; Haulena, Martin; Williams, D Colette; Dawson, John; Yandell, Brian S; Gulland, Frances M D

    2008-12-01

    Sedation in sea lions exhibiting abnormal neurologic signs may require modification of established sedatior protocols because of the likely interaction between effects of the sedative and physiologic changes in diseased animals The effects of two sedative combinations, 0.07 mg/kg medetomidine and 0.07 mg/kg medetomidine plus 0.2 mg/kg butorphanol, were compared between California sea lions (Zalophus californianus) with signs of neurologic dysfunctior (n=33) and without neurologic signs (n=8). Sedation depth was scored on a scale of 0 (no effect) to 4 (profound sedation) assessed by response to auditory, tactile, and visual stimuli at the time of perceived maximal sedative effect In the medetomidine-alone group, sea lions with neurologic signs attained a median sedation score of 4 compared to a median sedation score of 1 in the clinically normal sea lions. Sea lions with and without neurologic signs giver medetomidine-butorphanol attained a median sedation score of 4. No statistically significant difference in time to induction and respiratory rate was found between the two sedation protocols in all sea lions. In the sea lions with neurologic signs, the recovery time from medetomidine-butorphanol sedation was prolonged (P < 0.01) and minimum recorded heart rates, although remaining within normal physiologic limits, were lower (P = 0.02) when compared to the sea lions administered medetomidine alone. Muscle jerks were observed in many animals given medetomidine-butorphanol and were detrimental to the diagnostic quality of the electroencephalogram (EEG) recording. Medetomidine alone at a dose rate of 0.07 mg/kg thus provides adequate and safe sedation in sea lions with neurologic signs undergoing EEG evaluation. PMID:19110694

  16. 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

    2009-12-01

    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). PMID:19735983

  17. DEVELOPMENT OF RETROBULBAR AND AURICULOPALPEBRAL NERVE BLOCKS IN CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS).

    PubMed

    Gutiérrez, J; Simeone, C; Gulland, F; Johnson, S

    2016-03-01

    Eye lesions are commonly observed in pinnipeds. Clinical assessment is challenging because animals are often blepharospastic and under inhalant anesthesia the globe rotates ventrally, making observation difficult. Retrobulbar and auriculopalpebral nerve block techniques have been developed in other species to alleviate these difficulties and allow for a more thorough ophthalmic exam. Ocular nerve block techniques were developed for California sea lions (CSLs) (Zalophus californianus) using lidocaine hydrochloride 2%. To develop the retrobulbar block, a variety of needle sizes, anatomic approaches, and volumes of methylene blue were injected into the orbits of 10 CSL cadavers. An optimal technique, based on desired distribution of methylene blue dye into periocular muscles and tissues, was determined to be a two-point (ventrolateral and ventromedial) transpalpebral injection with a 20-ga, 1 1/2-inch needle. This technique was then tested using lidocaine on 26 anesthetized animals prior to euthanasia, and on one case with clinical ocular disease. A dose of 4 mg/kg of lidocaine was considered ideal, with positive results and minimal complications. The retrobulbar block had a 76.9% rate of success (using 4 mg/kg of lidocaine), which was defined as the globe returning at least halfway to its central orientation with mydriasis. No systemic adverse effects were noted with this technique. The auriculopalpebral nerve block was also adapted for CSLs from techniques described in dogs, cattle, and horses. Lidocaine was injected (2-3 ml) by subcutaneous infiltration lateral to the orbital rim, where the auriculopalpebral nerve branch courses over the zygomatic arch. This block was used in five blepharospastic animals that were anesthetized for ophthalmic examinations. The auriculopalpebral nerve block was successful in 60% of the cases, which was defined as reduction or elimination of blepharospasm for up to 3 hr. Success appeared to be dependent more on the location of

  18. Coccidioidomycosis and other systemic mycoses of marine mammals stranding along the central California, USA coast: 1998-2012.

    PubMed

    Huckabone, Sara E; Gulland, Frances M D; Johnson, Suzanne M; Colegrove, Kathleen M; Dodd, Erin M; Pappagianis, Demosthenes; Dunkin, Robin C; Casper, David; Carlson, Erin L; Sykes, Jane E; Meyer, Weiland; Miller, Melissa A

    2015-04-01

    A wide range of systemic mycoses have been reported from captive and wild marine mammals from North America. Examples include regionally endemic pathogens such as Coccidioides and Blastomyces spp., and novel pathogens like Cryptococcus gattii, which appear may have been introduced to North America by humans. Stranding and necropsy data were analyzed from three marine mammal stranding and response facilities on the central California coast to assess the prevalence, host demographics, and lesion distribution of systemic mycoses affecting locally endemic marine mammals. Between 1 January 1998 and 30 June 2012, >7,000 stranded marine mammals were necropsied at the three facilities. Necropsy and histopathology records were reviewed to identify cases of locally invasive or systemic mycoses and determine the nature and distribution of fungal lesions. Forty-one animals (0.6%) exhibited cytological, culture- or histologically confirmed locally invasive or systemic mycoses: 36 had coccidioidomycosis, two had zygomycosis, two had cryptococcosis, and one was systemically infected with Scedosporium apiospermum (an Ascomycota). Infected animals included 18 California sea lions (Zalophus californianus), 20 southern sea otters (Enhydra lutris nereis), two Pacific harbor seals (Phoca vitulina richardsi), one Dall's porpoise (Phocoenoides dalli), and one northern elephant seal (Mirounga angustirostris). Coccidioidomycosis was reported from 15 sea lions, 20 sea otters, and one harbor seal, confirming that Coccidioides spp. is the most common pathogen causing systemic mycosis in marine mammals stranding along the central California coast. We also report the first confirmation of C. gattii infection in a wild marine mammal from California and the first report of coccidioidomycosis in a wild harbor seal. Awareness of these pathogenic fungi during clinical care and postmortem examination is an important part of marine mammal population health surveillance and human health protection

  19. Mercury, cadmium, and lead in British otters

    SciTech Connect

    Mason, C.F.; Last, N.I.; Macdonald, S.M.

    1986-12-01

    Otters (subfamily Lutrinae), at the top of the food chain and feeding largely on fish, are likely to be especially vulnerable to the effects of bioaccumulating pollutants, while their aquatic habitat is often a sink for such chemicals derived from agricultural, industrial and domestic sources. The European otter (Lutra lutra) has shown substantial declines through much of its range over the past 30 years, which have been attributed to pollution by organochlorines. There are few published data on metals in tissues of European otters and these refer only to mercury. The present paper reports on burdens of mercury, cadmium and lead in tissues of a sample of British otters collected between 1982 and 1984.

  20. Trapping and handling of North American river otters (Lontra canadensis) in a managed marsh.

    PubMed

    Belfiore, Natalia M

    2008-03-01

    North American river otters (Lontra canadensis) were trapped in a managed marsh in northern California between July and November of 1998. Five trap types using several set configurations were utilized in this study. Otters were successfully captured with minimal injury and a relatively high trap rate (1 capture per 48 trap nights), with the use of No. 1.5 and No. 1.75 double-coil spring traps, and No. 11 double long spring traps on short chains in blind land sets, or in bank sets on one-way cables leading to land-buried stakes. Only 3 of 14 captures incurred more than minimal injuries, and all 3 of these were exacerbated by complications from traps attached to long chains. Otters were captured at any time of day, although activity appeared lowered between 0900 and 1900 hours. Otters were anesthetized for handling. Monitoring results and anesthetic complications are reported for 14 captures. Ketamine (15 mg/kg) and midazolam (0.5 mg/kg) provided a wide margin of safety, rapid induction at low injection volume, good anesthetic quality, handling time of about 30 min, and few complications. White blood cell counts were taken and appeared high relative to reported values in other studies. This trend is likely attributable to blood draws immediately after the animal had been held in a trap for several hours, in contrast to most other studies, in which blood was drawn days to weeks after being held in captivity. PMID:18432092

  1. Proteomic analysis of cerebrospinal fluid in California sea lions (Zalophus californianus) with domoic acid toxicosis identifies proteins associated with neurodegeneration.

    PubMed

    Neely, Benjamin A; Soper, Jennifer L; Gulland, Frances M D; Bell, P Darwin; Kindy, Mark; Arthur, John M; Janech, Michael G

    2015-12-01

    Proteomic studies including marine mammals are rare, largely due to the lack of fully sequenced genomes. This has hampered the application of these techniques toward biomarker discovery efforts for monitoring of health and disease in these animals. We conducted a pilot label-free LC-MS/MS study to profile and compare the cerebrospinal fluid from California sea lions with domoic acid toxicosis (DAT) and without DAT. Across 11 samples, a total of 206 proteins were identified (FDR<0.1) using a composite mammalian database. Several peptide identifications were validated using stable isotope labeled peptides. Comparison of spectral counts revealed seven proteins that were elevated in the cerebrospinal fluid from sea lions with DAT: complement C3, complement factor B, dickkopf-3, malate dehydrogenase 1, neuron cell adhesion molecule 1, gelsolin, and neuronal cell adhesion molecule. Immunoblot analysis found reelin to be depressed in the cerebrospinal fluid from California sea lions with DAT. Mice administered domoic acid also had lower hippocampal reelin protein levels suggesting that domoic acid depresses reelin similar to kainic acid. In summary, proteomic analysis of cerebrospinal fluid in marine mammals is a useful tool to characterize the underlying molecular pathology of neurodegenerative disease. All MS data have been deposited in the ProteomeXchange with identifier PXD002105 (http://proteomecentral.proteomexchange.org/dataset/PXD002105). PMID:26364553

  2. New Seismic CHIRP evidence for Transpression and Transtension Beneath the Salton Sea, California

    NASA Astrophysics Data System (ADS)

    Brothers, D.; Driscoll, N.; Kent, G.; Dingler, J.; Harding, A.; Babcock, J.

    2007-12-01

    The Salton Trough is a critical structure that separates spreading center dominated deformation in the Gulf of California and dextral strike-slip deformation along the San Andreas Fault (SAF) System. Geological and geophysical data suggest there is a transition within the Salton Trough near the town of Bombay Beach that separates transpression to the north from transtension in the south. To date, however, this transition remains poorly understood, in large part, due to a lack of geophysical subsurface data in the Salton Sea. We present preliminary analysis of > 350 line-km of high-resolution seismic CHIRP data acquired in 2006 and 2007 that imaged the different deformational styles beneath the Salton Sea, including several previously unidentified tectonic structures. The Extra Fault Zone (EFZ), which has been mapped onshore, is imaged in CHIRP profiles as an ~5 km wide deformation zone and can be traced offshore > 15 km along strike. Along the northern extent of the EFZ, ramp-flat deformation is observed with southward vergence. A marked angular unconformity between the Brawley and Cahuilla formations records fault-bend folding often predicted for ramp-flat thrust systems. Uplift and truncation of Pleistocene sediments along the northern edge of the EFZ is observed across the entire sea and appears to systematically increase towards the west. Onlapping sediments and growth folds in the Holocene Lake Cahuilla section to the north and south of the fault zone record ongoing uplift. Compression is also manifested in the bathymetry, with a mid-lake bathymetric high trending parallel the EFZ and separating southern and northern lake basins. The EFZ is interpreted to accommodate sinistral transpression related to clockwise- rotating crustal blocks. In contrast, at Bombay Beach the SAF takes an ~15 km releasing step towards the Imperial Fault, producing transtensional deformation through the Brawley Seismic Zone (BSZ). CHIRP profiles across the western margin of the BSZ

  3. Archeterokrohnia docrickettsae (Chaetognatha: Phragmophora: Heterokrohniidae), a new species of deep-sea arrow worm from the Gulf of California.

    PubMed

    Thuesen, Erik V; Haddock, Steven H D

    2013-01-01

    A new species of deep-sea chaetognath, Archeterokrohnia docrickettsae n. sp. is described from a single specimen captured by the ROV Doc Ricketts ~2 m above the sea floor at 3245 m depth in the Pescadero Basin of the Gulf of California, Mexico. This is the first record of a living specimen of Archeterokrohnia and the second known occurrence of Archeterokrohnia in the Pacific Ocean. In life, the head and trunk sections were orange, while the tail section was translucent, a unique colour pattern not before seen in chaetognaths. Observations of its swimming behaviour in situ are given. Comparisons are made with the three other species of Archeterokrohnia. At 28.5 mm in length, this is the largest known species of the genus. An artificial key to the four species of Archeterokrohnia is presented. PMID:26176108

  4. Air-sea CO2 fluxes measured by eddy covariance in a coastal station in Baja California, México

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Loza, L.; Ocampo-Torres, F. J.

    2016-05-01

    The influence of wave-associated parameters controlling turbulent CO2 fluxes through the air-sea water interface is evaluated in a coastal region. The study area, located within the Todos Santos Bay, Baja California, México, was found to be a weak sink of CO2 with a mean flux of -1.32 µmol m-2s-1. The low correlation found between flux and wind speed (r = 0.09), suggests that the influence of other forcing mechanisms, besides wind, is important for gas transfer modulation through the sea surface, at least for the conditions found in this study. In addition, the results suggest that for short periods where an intensification of the wave conditions occurs, a CO2 flux response increases the transport of gas to the ocean.

  5. USE OF SMALL OTTER TRAWLS IN COASTAL BIOLOGICAL SURVEYS

    EPA Science Inventory

    Ecological surveys using small otter trawls provide useful and informative data on demersal fish and epibenthic macroinvertebrates of coastal soft bottom areas. This report presents recommendations for selecting and using small otter trawls in coastal biological surveys and sugge...

  6. 50 CFR 216.85 - Walrus and Otter Islands.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false Walrus and Otter Islands. 216.85 Section... MAMMALS Pribilof Islands Administration § 216.85 Walrus and Otter Islands. By Executive Order 1044, dated February 27, 1909, Walrus and Otter Islands were set aside as bird reservations. All persons are...

  7. 50 CFR 216.85 - Walrus and Otter Islands.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Walrus and Otter Islands. 216.85 Section... MAMMALS Pribilof Islands Administration § 216.85 Walrus and Otter Islands. By Executive Order 1044, dated February 27, 1909, Walrus and Otter Islands were set aside as bird reservations. All persons are...

  8. 50 CFR 216.85 - Walrus and Otter Islands.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Walrus and Otter Islands. 216.85 Section... MAMMALS Pribilof Islands Administration § 216.85 Walrus and Otter Islands. By Executive Order 1044, dated February 27, 1909, Walrus and Otter Islands were set aside as bird reservations. All persons are...

  9. 50 CFR 216.85 - Walrus and Otter Islands.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false Walrus and Otter Islands. 216.85 Section... MAMMALS Pribilof Islands Administration § 216.85 Walrus and Otter Islands. By Executive Order 1044, dated February 27, 1909, Walrus and Otter Islands were set aside as bird reservations. All persons are...

  10. 50 CFR 216.85 - Walrus and Otter Islands.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false Walrus and Otter Islands. 216.85 Section... MAMMALS Pribilof Islands Administration § 216.85 Walrus and Otter Islands. By Executive Order 1044, dated February 27, 1909, Walrus and Otter Islands were set aside as bird reservations. All persons are...

  11. COINFECTION OF CALIFORNIA SEA LION ADENOVIRUS 1 AND A NOVEL POLYOMAVIRUS IN A HAWAIIAN MONK SEAL (NEOMONACHUS SCHAUINSLANDI).

    PubMed

    Cortés-Hinojosa, Galaxia; Doescher, Bethany; Kinsel, Michael; Lednicky, John; Loeb, Julia; Waltzek, Thomas; Wellehan, James F X

    2016-06-01

    The Hawaiian monk seal (Neomonachus schauinslandi) is an endangered species. Here, we present a clinical case of a 26-yr-old male Hawaiian monk seal (HMS) kept in an aquarium with a history of intermittent anorexia and evidence of renal disease. Histologic examination revealed eosinophilic intranuclear inclusions in the liver. Conventional nested PCR protocols were used to test for viruses, and it tested positive for adenovirus and polyomavirus, and negative for herpesvirus. The adenovirus partial polymerase gene is 100% homologous to that of California sea lion adenovirus 1 (CSLAdV-1). CSLAdV-1 causes viral hepatitis in CSL, and has recently been reported in different species of otariids in an aquarium in Japan ( Otaria flavescens and Arctocephalus pusillus ) and a sequence from Spain has been submitted in NCBI as Otaria flavescens adenovirus-1. The polyomavirus in this animal is a novel virus, and is the first polyomavirus discovered in Hawaiian monk seals. This new virus is designated Hawaiian monk seal polyomavirus (HMSPyV-1), and is 83% homologous to California sea lion Polyomavirus-1 (CSLPyV-1). This is the first report of viral coinfection in a HMS and clinical significance in this case remains unclear but may be associated with advanced age. PMID:27468013

  12. Standardized protocols for plasma clearance of iohexol are not appropriate for determination of glomerular filtration rates in anesthetized California sea lions (Zalophus californianus).

    PubMed

    Dennison, Sophie E; Gulland, Frances M D; Braselton, W Emmett

    2010-03-01

    Abstract: Plasma clearance of iohexol was evaluated in eight anesthetized California sea lions (Zalophus californianus), without evidence of renal dysfunction, to determine if the one-compartment model and the sample protocol used in dogs and cats could be applied to this species. Nonlinearity between samples in 75% (6/8) of sea lions voided those results. An additional two anesthetized sea lions were sampled at 5, 30, 45, 60, 120, 180, 240, and 360 min post iohexol injection and semi-logarithmic curves calculated. Plasma iohexol clearance values calculated by one-, two-, and noncompartment models were in poor agreement, suggesting that the standardized protocol described for dogs and cats cannot simply be applied to California sea lions, probably due to the effects of the dive reflex induced during anesthesia. PMID:20722269

  13. 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.

  14. Prevalence and characterization of Salmonella shed by captive and free-range California sea lions (Zalophus californianus) from a rehabilitation center and three state reserves along the California coast.

    PubMed

    Berardi, Terra; Shapiro, Karen; Byrne, Barbara A; Miller, Woutrina

    2014-09-01

    Salmonella is a genus of zoonotic bacteria that can infect a variety of animals, and may cause gastrointestinal disease in marine mammals. Many of the same Salmonella serotypes are shed by California sea lions (Zalophus californianus) and humans, which poses transmission questions and public health concerns. In this study, 454 fecal samples from three free-ranging California sea lion populations along the California coast and from animals undergoing rehabilitation at The Marine Mammal Center, Sausalito, California, were screened for the presence of Salmonella. In addition to fecal samples, 39 presumed vomitus samples were collected and processed. Of the 454 samples processed, 312 were from free-ranging sites and 142 were from rehabilitating California sea lions. A total of nine fecal samples were positive for Salmonella, yielding a 2.0% overall prevalence, as well as two presumed vomitus samples (5.1% prevalence). Salmonella shedding prevalence was 1.6% in samples collected from free-ranging animals, and 2.8% in rehabilitating animals. Four serotypes were found among the 11 positive samples, with Salmonella Enteritidis the most prevalent (64%). Antimicrobial resistance testing and pulsed-field gel electrophoresis were performed to further characterize isolates. Experiments were carried out to determine the minimal number of Salmonella required for detection by the methods used. It was determined that at least 10' colony-forming units per gram of feces was required for detection. The prevalence of Salmonella Enteritidis, and diversity of serotypes discovered is considerably different from those reported in previous studies. Overall, this study provides new insights into the epidemiology of Salmonella in California sea lions present in multi-use coastal ecosystems. PMID:25314819

  15. Use of a nesting platform by Gull-billed Terns and Black Skimmers at the Salton Sea, California

    USGS Publications Warehouse

    Molina, K.C.; Ricca, M.A.; Miles, A.K.; Schoneman, C.

    2009-01-01

    In 2006, we constructed an elevated nesting platform at the Salton Sea, California, and monitored its use by Gull-billed Terns and Black Skimmers over three subsequent breeding seasons. Black Skimmers were the first to colonize the platform with a total of five nests in 2006. In 2007 Gull-billed Terns colonized the platform with a total of 28 nests and the number of Black Skimmer nests increased to 20. Neither species nested on the platform in 2008. Low success for both species was probably influenced by at least two factors. First, when both species nested on the platform, nest densities were higher than is typical of their colonies on larger, earthen islands, and colony success may have been reduced by overcrowding. Second, lack of access to water may have reduced chicks' ability to thermoregulate effectively in the hot environment of the Salton Sea. Refinements to the size, design, and location of artificial nesting habitats are necessary to enhance productivity of colonial groundnesting birds at the Salton Sea successfully.

  16. At-sea distribution of radio-marked Ashy Storm-Petrels Oceanodroma homochroa captured on the California Channel Islands

    USGS Publications Warehouse

    Adams, J.; Takekawa, J.Y.

    2008-01-01

    Small, rare and wide-ranging pelagic birds are difficult to locate and observe at sea; little is therefore known regarding individual movements and habitat affinities among many of the world's storm-petrels (Family Hydrobatidae). We re-located 57 of 70 radio-marked Ashy Storm-Petrels Oceanodroma homochroa captured at three colonies in the California Channel Islands: Scorpion Rocks (2004, 2005), Santa Barbara Island (2004) and Prince Island (2005). Between 23 July and 22 September 2004, and 5 July and 4 August 2005, we flew 29 telemetry surveys, covered more than 65 000 km2 (2004) and 43 000 km2 (2005) of open ocean from San Nicolas Island north to the Farallon Islands and obtained 215 locations from 57 storm-petrels at sea. In both years, radio-marked storm-petrels were aggregated over the continental slope from Point Conception to Point Buchon, within the western Santa Barbara Channel, and over the Santa Cruz Basin between Santa Cruz, San Nicolas and Santa Barbara islands. Individuals captured in the Channel Islands ranged more than 600 km and were located as far north as Gulf of the Farallones National Marine Sanctuary. This is the first study to use radiotelemetry to determine the at-sea distribution and movements for any storm-petrel species.

  17. Late Quaternary depositional history, Holocene sea-level changes, and vertical crustal movement, southern San Francisco Bay, California

    USGS Publications Warehouse

    Atwater, Brian F.; Hedel, Charles W.; Helley, Edward J.

    1977-01-01

    Sediments collected for bridge foundation studies at southern San Francisco Bay, Calif., record estuaries that formed during Sangamon (100,000 years ago) and post-Wisconsin (less than 10,000 years ago) high stands of sea level. The estuarine deposits of Sangamon and post-Wisconsin ages are separated by alluvial and eolian deposits and by erosional unconformities and surfaces of nondeposition, features that indicate lowered base levels and oceanward migrations of the shoreline accompanying low stands of the sea. Estuarine deposits of mid-Wisconsin age appear to be absent, suggesting that sea level was not near its present height 30,000–40,000 years ago in central California. Holocene sea-level changes are measured from the elevations and apparent 14C ages of plant remains from 13 core samples. Uncertainties of ±2 to ±4 m in the elevations of the dated sea levels represent the sum of errors in determination of (1) sample elevation relative to present sea level, (2) sample elevation relative to sea level at the time of accumulation of the dated material, and (3) postdepositional subsidence of the sample due to compaction of underlying sediments. Sea level in the vicinity of southern San Francisco Bay rose about 2 cm/yr from 9,500 to 8,000 years ago. The rate of relative sea-level rise then declined about tenfold from 8,000 to 6,000 years ago, and it has averaged 0.1–0.2 cm/yr from 6,000 years ago to the present. This submergence history indicates that the rising sea entered the Golden Gate 10,000–11,000 years ago and spread across land areas as rapidly as 30 m/yr until 8,000 years ago. Subsequent shoreline changes were more gradual because of the decrease in rate of sea-level rise. Some of the sediments under southern San Francisco Bay appear to be below the level at which they initially accumulated. The vertical crustal movement suggested by these sediments may be summarized as follows: (1) Some Quaternary(?) sediments have sustained at least 100 m of

  18. 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

  19. Sea-floor Geology and Benthic Habitats of the San Pedro Shelf, California: the View in Google Earth

    NASA Astrophysics Data System (ADS)

    Wong, F. L.; Edwards, B. D.; Dartnell, P.; Phillips, E. L.

    2008-12-01

    The mainland shelf offshore of San Pedro in southern California is made up of a variety of geological materials and rich biological communities. The U.S. Geological Survey, in cooperation with Los Angeles and Orange County Sanitation District, surveyed the sea floor from the shoreline to a depth of 100 m with multibeam sonar, sediment samples, and still and video photography. Results of these surveys include detailed seafloor bathymetric data, seafloor facies interpreted from acoustic-backscatter data, sediment texture, seafloor photographs and video, and descriptions of plants and animals. These data sets are organized in a Geographic Information System (GIS) for spatial analyses. Virtual globes such as Google Earth add an intuitive and accessible tool for researchers and stakeholders to explore these vast data sets. Mud, sand, and bare-rock surfaces identified in the facies map are spatially correlated to still and video photographic images of these surfaces and the biologic communities that prefer or avoid particular geologic surfaces.

  20. Focal bacterial meningitis following ascending bite wound infection leading to paraparesis in a captive California sea lion (Zalophus californianus).

    PubMed

    Braun, Veronika; Eskens, Ulrich; Hartmann, Antje; Lang, Barbara; Kramer, Martin; Schmidt, Martin J

    2015-03-01

    Magnetic resonance imaging was performed on a 15-yr-old captive female California sea lion (Zalophus californianus) with a 2-wk history of progressive paraparesis and a 9-mo history of exudative skin lesion on the left thoracic wall. Magnetic resonance images showed a well-defined muscle infiltrating lesion ventrolateral to the seventh cervical to the third thoracic vertebra on the left side, which extended through the left intervertebral foramina C7 to T3 into the vertebral canal, causing spinal cord compression and displacement as well as inflammation of the spinal cord and nerves. This lesion surprisingly caused no forelimb deficits. Differential diagnoses included abscess formation or neoplasia. Pathologic examination revealed chronic focal purulent meningitis associated with widespread paraspinal fistulous inflammation originating from a chronic dermal ulcer. Mainly Escherichia coli var. haemolytica and Clostridium perfringens were identified as the underlying agents. PMID:25831587

  1. Seasonal to Decadal-Scale Variability in Satellite Ocean Color and Sea Surface Temperature for the California Current System

    NASA Technical Reports Server (NTRS)

    Mitchell, B. Greg; Kahru, Mati; Marra, John (Technical Monitor)

    2002-01-01

    Support for this project was used to develop satellite ocean color and temperature indices (SOCTI) for the California Current System (CCS) using the historic record of CZCS West Coast Time Series (WCTS), OCTS, WiFS and AVHRR SST. The ocean color satellite data have been evaluated in relation to CalCOFI data sets for chlorophyll (CZCS) and ocean spectral reflectance and chlorophyll OCTS and SeaWiFS. New algorithms for the three missions have been implemented based on in-water algorithm data sets, or in the case of CZCS, by comparing retrieved pigments with ship-based observations. New algorithms for absorption coefficients, diffuse attenuation coefficients and primary production have also been evaluated. Satellite retrievals are being evaluated based on our large data set of pigments and optics from CalCOFI.

  2. Exploitation and recovery of a sea urchin predator has implications for the resilience of southern California kelp forests

    PubMed Central

    Hamilton, Scott L.; Caselle, Jennifer E.

    2015-01-01

    Size-structured predator–prey interactions can be altered by the history of exploitation, if that exploitation is itself size-selective. For example, selective harvesting of larger sized predators can release prey populations in cases where only large individuals are capable of consuming a particular prey species. In this study, we examined how the history of exploitation and recovery (inside marine reserves and due to fisheries management) of California sheephead (Semicossyphus pulcher) has affected size-structured interactions with sea urchin prey in southern California. We show that fishing changes size structure by reducing sizes and alters life histories of sheephead, while management measures that lessen or remove fishing impacts (e.g. marine reserves, effort restrictions) reverse these effects and result in increases in density, size and biomass. We show that predation on sea urchins is size-dependent, such that the diet of larger sheephead is composed of more and larger sized urchins than the diet of smaller fish. These results have implications for kelp forest resilience, because urchins can overgraze kelp in the absence of top-down control. From surveys in a network of marine reserves, we report negative relationships between the abundance of sheephead and urchins and the abundance of urchins and fleshy macroalgae (including giant kelp), indicating the potential for cascading indirect positive effects of top predators on the abundance of primary producers. Management measures such as increased minimum size limits and marine reserves may serve to restore historical trophic roles of key predators and thereby enhance the resilience of marine ecosystems. PMID:25500572

  3. Use of Acoustic Transmitter-Equipped Remote Sedation to Aid in Tracking and Capture of Entangled California Sea Lions (Zalophus californianus).

    PubMed

    Frankfurter, Greg; DeRango, Eugene; Johnson, Shawn

    2016-07-01

    Free-ranging California sea lions ( Zalophus californianus ) with marine debris entanglements were darted with a combination of medetomidine, butorphanol, and midazolam by using acoustic transmitter-equipped darts. Of the 15 animals sedated, 13 (87%) reentered the water and were tracked by using a unidirectional hydrophone. Sea lions that entered the water continued to surface and breathe postsedation. There were three mortalities (20%) during the course of this study due to the following: suspected drowning caused by entrapment under a dock, overdose due to inaccurate weight estimation, and trauma caused by a dart puncturing the animal's abdomen. The drug combination, new dart design, and tracking techniques allowed for successful remote sedation and capture of California sea lions in high-risk situations and improved our ability to determine the final outcome for all cases. These methods allow targeting and capture of individual animals, while minimizing disturbance to other animals. PMID:27243155

  4. The protracted Holocene extinction of California's flightless sea duck (Chendytes lawi) and its implications for the Pleistocene overkill hypothesis

    PubMed Central

    Jones, T. L.; Porcasi, J. F.; Erlandson, J. M.; Dallas, H.; Wake, T. A.; Schwaderer, R.

    2008-01-01

    Bones of the flightless sea duck (Chendytes lawi) from 14 archaeological sites along the California coast indicate that humans hunted the species for at least 8,000 years before it was driven to extinction. Direct 14C dates on Chendytes bones show that the duck was exploited on the southern California islands as early as ≈11,150–10,280 calendar years B.P., and on the mainland by at least 8,500 calendar years B.P. The youngest direct date of 2,720–2,350 calendar years B.P., combined with the absence of Chendytes bones from hundreds of late Holocene sites, suggests that the species was extinct by ≈2,400 years ago. Although the extinction of Chendytes clearly resulted from human overhunting, its demise raises questions about the Pleistocene overkill model, which suggests that megafauna were driven to extinction in a blitzkrieg fashion by Native Americans ≈13,000 years ago. That the extermination of Chendytes was so protracted and archaeologically visible suggests that, if the terminal Pleistocene megafauna extinctions were primarily the result of human exploitation, there should also be a long and readily detectable archaeological record of their demise. The brief window now attributed to the Clovis culture (≈13,300–12,900 B.P.) seems inconsistent with an overhunting event. PMID:18334640

  5. Organochlorine residues in northeaster Alberta otters

    SciTech Connect

    Somers, J.D.; Goski, B.C.; Barrett, M.W.

    1987-11-01

    The use of organochlorine pesticides in North America has for the most part been legislatively curtailed during the last decade, and North American production of polychlorinated biphenyls (PCS's) was stopped in the 1970's. However, monitoring of chemical residues in fish and wildlife indicates that these persistent compound are still much in evidence throughout North America. Data on chemical residues in Alberta wildlife, particularly non-migratory species, is for the most part unknown. Otters (Lutra canadensis) are consumers of fish, invertebrates, amphibians and small mammals cohabiting their aquatic habitat. As carnivores at the terminus of their respective food chains, semi-aquatic mammals such as otter and mink (Mustela vison) may be expected to accumulate pesticides, PCBs and heavy metals. Otters are relatively sedentary and monitoring of chemical residues in their tissues might yield a diverse contaminant profile unique to the specific environs from which the animals are collected. The purpose of this report is to present chemical residue data for otters collected from aquatic habitats in northeastern Alberta.

  6. 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. PMID:25373985

  7. 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...

  8. 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...

  9. 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...

  10. Serum profiling by MALDI-TOF mass spectrometry as a diagnostic tool for domoic acid toxicosis in California sea lions

    PubMed Central

    2012-01-01

    Background There are currently no reliable markers of acute domoic acid toxicosis (DAT) for California sea lions. We investigated whether patterns of serum peptides could diagnose acute DAT. Serum peptides were analyzed by MALDI-TOF mass spectrometry from 107 sea lions (acute DAT n = 34; non-DAT n = 73). Artificial neural networks (ANN) were trained using MALDI-TOF data. Individual peaks and neural networks were qualified using an independent test set (n = 20). Results No single peak was a good classifier of acute DAT, and ANN models were the best predictors of acute DAT. Performance measures for a single median ANN were: sensitivity, 100%; specificity, 60%; positive predictive value, 71%; negative predictive value, 100%. When 101 ANNs were combined and allowed to vote for the outcome, the performance measures were: sensitivity, 30%; specificity, 100%; positive predictive value, 100%; negative predictive value, 59%. Conclusions These results suggest that MALDI-TOF peptide profiling and neural networks can perform either as a highly sensitive (100% negative predictive value) or a highly specific (100% positive predictive value) diagnostic tool for acute DAT. This also suggests that machine learning directed by populations of predictive models offer the ability to modulate the predictive effort into a specific type of error. PMID:22429742

  11. DISCOVERY OF THREE NOVEL COCCIDIAN PARASITES INFECTING CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS), WITH EVIDENCE OF SEXUAL REPLICATION AND INTERSPECIES PATHOGENICITY

    PubMed Central

    Colegrove, Kathleen M.; Grigg, Michael E.; Carlson-Bremer, Daphne; Miller, Robin H.; Gulland, Frances M. D.; Ferguson, David J. P.; Rejmanek, Daniel; Barr, Bradd C.; Nordhausen, Robert; Melli, Ann C.; Conrad, Patricia A.

    2016-01-01

    Enteric protozoal infection was identified in 5 stranded California sea lions (Zalophus californianus). Microscopically, the apical cytoplasm of distal jejunal enterocytes contained multiple stages of coccidian parasites, including schizonts with merozoites and spherical gametocytes, which were morphologically similar to coccidians. By histopathology, organisms appeared to be confined to the intestine and accompanied by only mild enteritis. Using electron microscopy, both sexual (microgametocytes, macrogamonts) and asexual (schizonts, merozoites) coccidian stages were identified in enterocytes within parasitophorous vacuoles, consistent with apicomplexan development in a definitive host. Serology was negative for tissue cyst-forming coccidians, and immunohistochemistry for Toxoplasma gondii was inconclusive and negative for Neospora caninum and Sarcocystis neurona. Analysis of ITS-1 gene sequences amplified from frozen or formalin-fixed paraffin-embedded intestinal sections identified DNA sequences with closest homology to Neospora sp. (80%); these novel sequences were referred to as belonging to coccidian parasites ‘‘A,’’ ‘‘B,’’ and ‘‘C.’’ Subsequent molecular analyses completed on a neonatal harbor seal (Phoca vitulina) with protozoal lymphadenitis, hepatitis, myocarditis, and encephalitis showed that it was infected with a coccidian parasite bearing the ‘‘C’’ sequence type. Our results indicate that sea lions likely serve as definitive hosts for 3 newly described coccidian parasites, at least 1 of which is pathogenic in a marine mammal intermediate host species. PMID:21495828

  12. Discovery of three novel coccidian parasites infecting California sea lions (Zalophus californianus), with evidence of sexual replication and interspecies pathogenicity.

    PubMed

    Colegrove, Kathleen M; Grigg, Michael E; Carlson-Bremer, Daphne; Miller, Robin H; Gulland, Frances M D; Ferguson, David J P; Rejmanek, Daniel; Barr, Bradd C; Nordhausen, Robert; Melli, Ann C; Conrad, Patricia A

    2011-10-01

    Enteric protozoal infection was identified in 5 stranded California sea lions (Zalophus californianus). Microscopically, the apical cytoplasm of distal jejunal enterocytes contained multiple stages of coccidian parasites, including schizonts with merozoites and spherical gametocytes, which were morphologically similar to coccidians. By histopathology, organisms appeared to be confined to the intestine and accompanied by only mild enteritis. Using electron microscopy, both sexual (microgametocytes, macrogamonts) and asexual (schizonts, merozoites) coccidian stages were identified in enterocytes within parasitophorous vacuoles, consistent with apicomplexan development in a definitive host. Serology was negative for tissue cyst-forming coccidians, and immunohistochemistry for Toxoplasma gondii was inconclusive and negative for Neospora caninum and Sarcocystis neurona. Analysis of ITS-1 gene sequences amplified from frozen or formalin-fixed paraffin-embedded intestinal sections identified DNA sequences with closest homology to Neospora sp. (80%); these novel sequences were referred to as belonging to coccidian parasites "A," "B," and "C." Subsequent molecular analyses completed on a neonatal harbor seal (Phoca vitulina) with protozoal lymphadenitis, hepatitis, myocarditis, and encephalitis showed that it was infected with a coccidian parasite bearing the "C" sequence type. Our results indicate that sea lions likely serve as definitive hosts for 3 newly described coccidian parasites, at least 1 of which is pathogenic in a marine mammal intermediate host species. PMID:21495828

  13. Temporal variations in air-sea CO2 exchange near large kelp beds near San Diego, California

    NASA Astrophysics Data System (ADS)

    Ikawa, Hiroki; Oechel, Walter C.

    2015-01-01

    study presents nearly continuous air-sea CO2 flux for 7 years using the eddy covariance method for nearshore water near San Diego, California, as well as identifying environmental processes that appear to control temporal variations in air-sea CO2 flux at different time scales using time series decomposition. Monthly variations in CO2 uptake are shown to be positively influenced by photosynthetically active photon flux density (PPFD) and negatively related to wind speeds. In contrast to the monthly scale, wind speeds often influenced CO2 uptake positively on an hourly scale. Interannual variations in CO2 flux were not correlated with any independent variables, but did reflect surface area of the adjacent kelp bed in the following year. Different environmental influences on CO2 flux at different temporal scales suggest the importance of long-term flux monitoring for accurately identifying important environmental processes for the coastal carbon cycle. Overall, the study area was a strong CO2 sink into the sea (CO2 flux of ca. -260 g C m-2 yr-1). If all coastal areas inhabited by macrophytes had a similar CO2 uptake rate, the net CO2 uptake from these areas alone would roughly equal the net CO2 sink estimated for the entire global coastal ocean to date. A similar-strength CO2 flux, ranging between -0.09 and -0.01 g C m-2 h-1, was also observed over another kelp bed from a pilot study of boat-based eddy covariance measurements.

  14. Effects of five southern California macroalgal diets on consumption, growth, and gonad weight, in the purple sea urchin Strongylocentrotus purpuratus

    PubMed Central

    Byrnes, Jarrett E.K.; Reed, Daniel C.

    2015-01-01

    Consumer growth and reproductive capacity are direct functions of diet. Strongylocentrotid sea urchins, the dominant herbivores in California kelp forests, strongly prefer giant kelp (Macrocystis pyrifera), but are highly catholic in their ability to consume other species. The biomass of Macrocystis fluctuates greatly in space and time, and the extent to which urchins can use alternate species of algae or a mixed diet of multiple algal species to maintain fitness when giant kelp is unavailable is unknown. We experimentally examined the effects of single and mixed species diets on consumption, growth and gonad weight in the purple sea urchin Strongylocentrotus purpuratus. Urchins were fed single species diets consisting of one of four common species of macroalgae (the kelps Macrocystis pyrifera and Pterygophora californica, and the red algae Chondracanthus corymbiferus and Rhodymenia californica (hereafter referred to by genus)) or a mixed diet containing all four species ad libitum over a 13-week period in a controlled laboratory setting. Urchins fed Chondracanthus, Macrocystis and a mixed diet showed the highest growth (in terms of test diameter, wet weight and jaw length) and gonad weight, while urchins fed Pterygophora and Rhodymenia showed the lowest. Urchins consumed their preferred food, Macrocystis, at the highest rate when offered a mixture, but consumed Chondracanthus or Macrocystis at similar rates when the two algae were offered alone. The differences in urchin feeding behavior and growth observed between these diet types suggest the relative availability of the algae tested here could affect urchin populations and their interactions with the algal assemblage. The fact that the performance of urchins fed Chondracanthus was similar or higher than those fed the preferred Macrocystis suggests that the availability of the former could could sustain growth and reproduction of purple sea urchins during times of low Macrocystis abundance as is common following

  15. Response of biological production and air-sea CO2 fluxes to upwelling intensification in the California and Canary Current Systems

    NASA Astrophysics Data System (ADS)

    Lachkar, Zouhair; Gruber, Nicolas

    2013-01-01

    Upwelling-favorable winds have increased in most Eastern Boundary Upwelling Systems (EBUS) in the last decades, and it is likely that they increase further in response to global climate change. Here, we explore the response of biological production and air-sea CO2 fluxes to upwelling intensification in two of the four major EBUS, namely the California Current System (California CS) and Canary Current System (Canary CS). To this end, we use eddy-resolving regional ocean models on the basis of the Regional Oceanic Modeling System (ROMS) to which we have coupled a NPZD-type ecosystem model and a biogeochemistry module describing the carbon cycle and subject these model configurations to an idealized increase in the wind stress. We find that a doubling of the wind-stress doubles net primary production (NPP) in the southern California CS and central and northern Canary CS, while it leads to an increase of less than 50% in the central and northern California CS as well as in the southern Canary CS. This differential response is a result of i) different nutrient limitation states with higher sensitivity to upwelling intensification in regions where nutrient limitation is stronger and ii) more efficient nutrient assimilation by biology in the Canary CS relative to the California CS because of a faster nutrient-replete growth rate and longer nearshore water residence times. In the regions where production increases commensurably with upwelling intensification, the enhanced net biological uptake of CO2 compensates the increase in upwelling driven CO2 outgassing, resulting in only a small change in the biological pump efficiency and hence in a small sensitivity of air-sea CO2 fluxes to upwelling intensification. In contrast, in the central California CS as well as in the southern Canary CS around Cape Blanc, the reduced biological efficiency enhances the CO2 outgassing and leads to a substantial sensitivity of the air-sea CO2 fluxes to upwelling intensification.

  16. PCB congeners in tissues of European otter (Lutra lutra)

    SciTech Connect

    Mason, C.F.; Ratford, J.R. )

    1994-10-01

    Otters (Lutra lutra) have declined over much of their European range during the past forty years and are now absent from large areas of the lowlands of Western Europe. The most likely cause of the decline is the effects of bioaccumulating contaminants, organochlorine pesticides and PCBs having been implicated. There have been several recent studies of organochlorine residues (pesticides and PCBs) in otter tissues and scats have been used to monitor residues in otter populations. However, only from The Netherlands have data on individual PCB congeners in otter tissues and scats been reported; this Dutch otter population is now extirpated. We report a survey of PCB congeners in samples of tissues and scats from several populations of otters. 21 refs., 3 tabs.

  17. Analysis of airborne Doppler lidar measurements of the extended California sea breeze

    NASA Technical Reports Server (NTRS)

    Carroll, John J.

    1989-01-01

    Airborne Doppler lidar data obtained by NASA near the top of the PBL in the central valley of California are analyzed. The experimental conditions and quality of the data are described. Wind vectors are produced on a geographic grid divided into 1-km square cells. The resulting wind field has features similar to those seen in ground level wind observations. It is suggested that, although the analysis is labor intensive and cumbersome, it produces a previously unattainable high-resolution depiction of air flow over a broad region.

  18. Coherent Cloudiness Variability from Sierra Nevada to the Sea in California

    NASA Astrophysics Data System (ADS)

    Sumargo, E.; Cayan, D. R.

    2015-12-01

    Cloud variability serves as the principal modulator of incoming solar radiation. These cloud effects are particularly important in mountain settings such as the Sierra Nevada in California, because the solar irradiance is a primary input to the snowpack energy balance. An important, unanswered question is whether the mountain clouds over the Sierra Nevada are only one part of a larger-scale system or whether they vary distinctly from cloud patterns upstream over the Central Valley and coastal areas. To address this question we investigate cloud variability over California using 19 years (1996-2014) of GOES visible albedo product with 4-km spatial and 30-minute temporal resolutions. Two domains are considered: high elevations in which only higher (>800m) elevations are included, thus excluding the coast and valley clouds, and all elevations which includes all elevations from the offshore North Pacific to Nevada. Our focus is on the spring and early summer period, which is crucial because it includes much of the snowmelt runoff from the Sierra Nevada. Inter-annual variation of cloudiness, represented by the coefficient of variation of cloud albedo, reveals the highest relative variability from California coasts and lowlands in the winter and spring to highlands and mountains in the summer and autumn. This pattern also occurs across shorter to longer time-scales, with coefficient of variation ranging from 30-180% on daily scale to 5-40% on seasonal scale. Considering the spatial structure of anomalous cloudiness, rotated EOF (REOF) analyses of de-seasonalized daily cloud albedo in the high elevation domain yields patterns and temporal variations that are well correlated with those from the all elevation domain. This indicates that, to a large degree, the mountain clouds co-vary with those over the Central Valley and the California coast, even though the valley and coastal clouds include low stratus clouds. The monthly standard deviations of the amplitudes of the time

  19. Sea-Floor Images and Data from Multibeam Surveys in San Francisco Bay, Southern California, Hawaii, the Gulf of Mexico, and Lake Tahoe, California-Nevada

    USGS Publications Warehouse

    Dartnell, Peter; Gardiner, James V.

    1999-01-01

    Accurate base maps are a prerequisite for any geologic study, regardless of the objectives. Land-based studies commonly utilize aerial photographs, USGS 7.5-minute quadrangle maps, and satellite images as base maps. Until now, studies that involve the ocean floor have been at a disadvantage due to an almost complete lack of accurate marine base maps. Many base maps of the sea floor have been constructed over the past century but with a wide range in navigational and depth accuracies. Only in the past few years has marine surveying technology advanced far enough to produce navigational accuracy of 1 meter and depth resolutions of 50 centimeters. The Pacific Seafloor Mapping Project of the U.S. Geological Survey's, Western Coastal and Marine Geology Program, Menlo Park, California, U.S.A., in cooperation with the Ocean Mapping Group, University of New Brunswick, Fredericton, Canada, is using this new technology to systematically map the ocean floor and lakes. This type of marine surveying, called multibeam surveying, collects high-resolution bathymetric and backscatter data that can be used for various base maps, GIS coverages, and scientific visualization methods. This is an interactive CD-ROM that contains images, movies, and data of all the surveys the Pacific Seafloor Mapping Project has completed up to January 1999. The images and movies on this CD-ROM, such as shaded relief of the bathymetry, backscatter, oblique views, 3-D views, and QuickTime movies help the viewer to visualize the multibeam data. This CD-ROM also contains ARC/INFO export (.e00) files and full-resolution TIFF images of all the survey sites that can be downloaded and used in many GIS packages.

  20. Microearthquake Study of the Salton Sea Geothermal Field, California: Evidence of Stress Triggering - Masters Thesis

    SciTech Connect

    Holland, Austin Adams

    2002-02-01

    A digital network of 24 seismograph stations was operated from September 15, 1987 to September 30, 1988, by Lawrence Livermore National Laboratory and Unocal as part of the Salton Sea Scientific Drilling Project to study seismicity related to tectonics and geothermal activity near the drilling site. More than 2001 microearthquakes were relocated in this study in order to image any pervasive structures that may exist within the Salton Sea geothermal field. First, detailed velocity models were obtained through standard 1-D inversion techniques. These velocity models were then used to relocate events using both single event methods and Double-Differencing, a joint hypocenter location method. An anisotropic velocity model was built from anisotropy estimates obtained from well logs within the study area. During the study period, the Superstition wills sequence occurred with two moderate earthquakes of MS 6.2 and MS 6.6. These moderate earthquakes caused a rotation of the stress field as observed from the inversion of first motion data from microearthquakes at the Salton Sea geothermal field. Coulomb failure analysis also indicates that microearthquakes occurring after the Superstition Hills sequence are located within a region of stress increase suggesting stress triggering caused by the moderate earthquakes.

  1. New insights into North America-Pacific Plate boundary deformation from Lake Tahoe, Salton Sea and southern Baja California

    NASA Astrophysics Data System (ADS)

    Brothers, Daniel Stephen

    Five studies along the Pacific-North America (PA-NA) plate boundary offer new insights into continental margin processes, the development of the PA-NA tectonic margin and regional earthquake hazards. This research is based on the collection and analysis of several new marine geophysical and geological datasets. Two studies used seismic CHIRP surveys and sediment coring in Fallen Leaf Lake (FLL) and Lake Tahoe to constrain tectonic and geomorphic processes in the lakes, but also the slip-rate and earthquake history along the West Tahoe-Dollar Point Fault. CHIRP profiles image vertically offset and folded strata that record deformation associated with the most recent event (MRE). Radiocarbon dating of organic material extracted from piston cores constrain the age of the MRE to be between 4.1--4.5 k.y. B.P. Offset of Tioga aged glacial deposits yield a slip rate of 0.4--0.8 mm/yr. An ancillary study in FLL determined that submerged, in situ pine trees that date to between 900-1250 AD are related to a medieval megadrought in the Lake Tahoe Basin. The timing and severity of this event match medieval megadroughts observed in the western United States and in Europe. CHIRP profiles acquired in the Salton Sea, California provide new insights into the processes that control pull-apart basin development and earthquake hazards along the southernmost San Andreas Fault. Differential subsidence (>10 mm/yr) in the southern sea suggests the existence of northwest-dipping basin-bounding faults near the southern shoreline. In contrast to previous models, the rapid subsidence and fault architecture observed in the southern part of the sea are consistent with experimental models for pull-apart basins. Geophysical surveys imaged more than 15 ˜N15°E oriented faults, some of which have produced up to 10 events in the last 2-3 kyr. Potentially 2 of the last 5 events on the southern San Andreas Fault (SAF) were synchronous with rupture on offshore faults, but it appears that ruptures on

  2. The Use of Surrogate Data in Demographic Population Viability Analysis: A Case Study of California Sea Lions

    PubMed Central

    2015-01-01

    Reliable data necessary to parameterize population models are seldom available for imperiled species. As an alternative, data from populations of the same species or from ecologically similar species have been used to construct models. In this study, we evaluated the use of demographic data collected at one California sea lion colony (Los Islotes) to predict the population dynamics of the same species from two other colonies (San Jorge and Granito) in the Gulf of California, Mexico, for which demographic data are lacking. To do so, we developed a stochastic demographic age-structured matrix model and conducted a population viability analysis for each colony. For the Los Islotes colony we used site-specific pup, juvenile, and adult survival probabilities, as well as birth rates for older females. For the other colonies, we used site-specific pup and juvenile survival probabilities, but used surrogate data from Los Islotes for adult survival probabilities and birth rates. We assessed these models by comparing simulated retrospective population trajectories to observed population trends based on count data. The projected population trajectories approximated the observed trends when surrogate data were used for one colony but failed to match for a second colony. Our results indicate that species-specific and even region-specific surrogate data may lead to erroneous conservation decisions. These results highlight the importance of using population-specific demographic data in assessing extinction risk. When vital rates are not available and immediate management actions must be taken, in particular for imperiled species, we recommend the use of surrogate data only when the populations appear to have similar population trends. PMID:26413746

  3. The Use of Surrogate Data in Demographic Population Viability Analysis: A Case Study of California Sea Lions.

    PubMed

    Hernández-Camacho, Claudia J; Bakker, Victoria J; Aurioles-Gamboa, David; Laake, Jeff; Gerber, Leah R

    2015-01-01

    Reliable data necessary to parameterize population models are seldom available for imperiled species. As an alternative, data from populations of the same species or from ecologically similar species have been used to construct models. In this study, we evaluated the use of demographic data collected at one California sea lion colony (Los Islotes) to predict the population dynamics of the same species from two other colonies (San Jorge and Granito) in the Gulf of California, Mexico, for which demographic data are lacking. To do so, we developed a stochastic demographic age-structured matrix model and conducted a population viability analysis for each colony. For the Los Islotes colony we used site-specific pup, juvenile, and adult survival probabilities, as well as birth rates for older females. For the other colonies, we used site-specific pup and juvenile survival probabilities, but used surrogate data from Los Islotes for adult survival probabilities and birth rates. We assessed these models by comparing simulated retrospective population trajectories to observed population trends based on count data. The projected population trajectories approximated the observed trends when surrogate data were used for one colony but failed to match for a second colony. Our results indicate that species-specific and even region-specific surrogate data may lead to erroneous conservation decisions. These results highlight the importance of using population-specific demographic data in assessing extinction risk. When vital rates are not available and immediate management actions must be taken, in particular for imperiled species, we recommend the use of surrogate data only when the populations appear to have similar population trends. PMID:26413746

  4. 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).

  5. MANAGEMENT OF ACUTE RENAL FAILURE WITH DELAYED HYPERCALCEMIA SECONDARY TO SARCOCYSTIS NEURONA-INDUCED MYOSITIS AND RHABDOMYOLYSIS IN A CALIFORNIA SEA LION (ZALOPHUS CALIFORNIANUS).

    PubMed

    Alexander, Amy B; Hanley, Christopher S; Duncan, Mary C; Ulmer, Kyle; Padilla, Luis R

    2015-09-01

    A 3-yr-old captive-born California sea lion (Zalophus californianus) developed Sarcocystis neurona-induced myositis and rhabdomyolysis that led to acute renal failure. The sea lion was successfully managed with fluid therapy, antiprotozoals, antibiotics, anti-inflammatories, antiemetics, gastroprotectants, and diuretics, but developed severe delayed hypercalcemia, a syndrome identified in humans after traumatic or exertion-induced rhabdomyolysis. Treatment with calcitonin was added to the management, and the individual recovered fully. The case emphasizes that animals with rhabdomyolysis-induced renal failure risk developing delayed hypercalcemia, which may be life threatening, and calcium levels should be closely monitored past the resolution of renal failure. PMID:26352981

  6. 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).

  7. Impacts of sea level rise and climate change on coastal plant species in the central California coast

    PubMed Central

    Chang, Michelle Y.; Fulda, Matthew T.; Berlin, Jonathan A.; Freed, Rachel E.; Soo-Hoo, Melissa M.; Revell, Dave L.; Ikegami, Makihiko; Flint, Lorraine E.; Flint, Alan L.; Kendall, Bruce E.

    2015-01-01

    Local increases in sea level caused by global climate change pose a significant threat to the persistence of many coastal plant species through exacerbating inundation, flooding, and erosion. In addition to sea level rise (SLR), climate changes in the form of air temperature and precipitation regimes will also alter habitats of coastal plant species. Although numerous studies have analyzed the effect of climate change on future habitats through species distribution models (SDMs), none have incorporated the threat of exposure to SLR. We developed a model that quantified the effect of both SLR and climate change on habitat for 88 rare coastal plant species in San Luis Obispo, Santa Barbara, and Ventura Counties, California, USA (an area of 23,948 km2). Our SLR model projects that by the year 2100, 60 of the 88 species will be threatened by SLR. We found that the probability of being threatened by SLR strongly correlates with a species’ area, elevation, and distance from the coast, and that 10 species could lose their entire current habitat in the study region. We modeled the habitat suitability of these 10 species under future climate using a species distribution model (SDM). Our SDM projects that 4 of the 10 species will lose all suitable current habitats in the region as a result of climate change. While SLR accounts for up to 9.2 km2 loss in habitat, climate change accounts for habitat suitability changes ranging from a loss of 1,439 km2 for one species to a gain of 9,795 km2 for another species. For three species, SLR is projected to reduce future suitable area by as much as 28% of total area. This suggests that while SLR poses a higher risk, climate changes in precipitation and air temperature represents a lesser known but potentially larger risk and a small cumulative effect from both. PMID:26020011

  8. Impacts of sea level rise and climate change on coastal plant species in the central California coast.

    PubMed

    Garner, Kendra L; Chang, Michelle Y; Fulda, Matthew T; Berlin, Jonathan A; Freed, Rachel E; Soo-Hoo, Melissa M; Revell, Dave L; Ikegami, Makihiko; Flint, Lorraine E; Flint, Alan L; Kendall, Bruce E

    2015-01-01

    Local increases in sea level caused by global climate change pose a significant threat to the persistence of many coastal plant species through exacerbating inundation, flooding, and erosion. In addition to sea level rise (SLR), climate changes in the form of air temperature and precipitation regimes will also alter habitats of coastal plant species. Although numerous studies have analyzed the effect of climate change on future habitats through species distribution models (SDMs), none have incorporated the threat of exposure to SLR. We developed a model that quantified the effect of both SLR and climate change on habitat for 88 rare coastal plant species in San Luis Obispo, Santa Barbara, and Ventura Counties, California, USA (an area of 23,948 km(2)). Our SLR model projects that by the year 2100, 60 of the 88 species will be threatened by SLR. We found that the probability of being threatened by SLR strongly correlates with a species' area, elevation, and distance from the coast, and that 10 species could lose their entire current habitat in the study region. We modeled the habitat suitability of these 10 species under future climate using a species distribution model (SDM). Our SDM projects that 4 of the 10 species will lose all suitable current habitats in the region as a result of climate change. While SLR accounts for up to 9.2 km(2) loss in habitat, climate change accounts for habitat suitability changes ranging from a loss of 1,439 km(2) for one species to a gain of 9,795 km(2) for another species. For three species, SLR is projected to reduce future suitable area by as much as 28% of total area. This suggests that while SLR poses a higher risk, climate changes in precipitation and air temperature represents a lesser known but potentially larger risk and a small cumulative effect from both. PMID:26020011

  9. Evolution of the 2014-2015 sea surface temperature warming in the central west coast of Baja California, Mexico, recorded by remote sensing

    NASA Astrophysics Data System (ADS)

    Robinson, Carlos J.

    2016-07-01

    Extraordinarily warm sea surface temperatures were present in the California Current System during 2014-2015. In several locations surface waters temperature registered new record high in the recent time series. This study focuses in the evolution of the warming in the southern part of the California Current System (CCS), off the west coast of Baja California, Mexico. Analysis of monthly sea surface temperature (SST), sea level pressure, and wind speed as measured by satellite from January 1988 to December 2015 show that recent warming occurred during two distinct periods. From May 2014 to April 2015, SST warming was related to weak coastal winds not associated to El Niño. During this period occurred the longest sustained record of 15 months of negative wind anomalies in the series. A reduction of wind stress suggests a weakened coastal upwelling, and consequently, cold water not transported into the surface. The second process of warming occurred from September to December 2015, during a strong El Niño condition.

  10. Senile plaques and cerebral amyloid angiopathy in an aged California sea lion (Zalophus californianus).

    PubMed

    Takahashi, Erika; Kuribayashi, Hiroyuki; Chambers, James Kenn; Imamura, Emi; Une, Yumi

    2014-09-01

    Senile plaques (SPs) and cerebral amyloid angiopathy (CAA) consisting of β-amyloid (Aβ) are major features in the brain of Alzheimer's disease (AD) patients and elderly humans and animals. In this study, we report the finding of SPs and CAA in an aged sea lion (30 years), which is the first demonstration of AD-related pathological changes in a marine animal. Histologically, SPs were observed at the cerebral cortex, most frequently at the frontal lobe, with two morphologically different types: the small round type and the large granular type. Only the small round SPs were positive for Congo red staining. The SPs were equally immunoreactive to Aβ40 and Aβ42 and were mainly composed of Aβ with an N-terminal pyroglutamate residue at position 3. Amyloid depositions at vessel walls were noted at the meninges and within the parenchyma. Interestingly, double immunofluorescence staining for Aβ40 and Aβ42 showed that the two subtypes were deposited segmentally in different parts of the vessel walls. The lesions observed in the sea lion suggest that Aβ deposition is widely present in various animal species, including marine mammals; however, the peculiar deposits similar to cotton wool plaques and the specific pattern of CAA are characteristic features of this animal. PMID:24779910

  11. Auditory and behavioral responses of California sea lions (Zalophus californianus) to single underwater impulses from an arc-gap transducer

    NASA Astrophysics Data System (ADS)

    Finneran, James J.; Dear, Randall; Carder, Donald A.; Ridgway, Sam H.

    2003-09-01

    A behavioral response paradigm was used to measure underwater hearing thresholds in two California sea lions (Zalophus californianus) before and after exposure to underwater impulses from an arc-gap transducer. Preexposure and postexposure hearing thresholds were compared to determine if the subjects experienced temporary shifts in their masked hearing thresholds (MTTS). Hearing thresholds were measured at 1 and 10 kHz. Exposures consisted of single underwater impulses produced by an arc-gap transducer referred to as a ``pulsed power device'' (PPD). The electrical charge of the PPD was varied from 1.32 to 2.77 kJ; the distance between the subject and the PPD was varied over the range 3.4 to 25 m. No MTTS was observed in either subject at the highest received levels: peak pressures of approximately 6.8 and 14 kPa, rms pressures of approximately 178 and 183 dB re: 1 μPa, and total energy fluxes of 161 and 163 dB re: 1 μPa2s for the two subjects. Behavioral reactions to the tests were observed in both subjects. These reactions primarily consisted of temporary avoidance of the site where exposure to the PPD impulse had previously occurred.

  12. Atmospheric dry deposition in the vicinity of the Salton Sea, California - II: Measurement and effects of an enhanced evaporation system

    USGS Publications Warehouse

    Alonso, R.; Bytnerowicz, A.; Yee, J.L.; Boarman, W.I.

    2005-01-01

    A study was conducted to determine the effects of salt spray drift from pilot technologies employed by the US Bureau of Reclamation on deposition rates of various air-born ions. An enhanced evaporation system (EES) was tested in the field at the Salton Sea, California. Dry deposition of NO3-, NH4+, SO42-, Cl-, Ca2+, Na+, K+ and Se was assessed by using nylon filters and branches of natural vegetation exposed for one-week long periods. The simultaneous exposure of both lyophilized branches and branches of live plants offered important information highlighting the dynamics of deposited ions on vegetation. The EES significantly increased the deposition rates of Cl-, SO42- and Na+ in an area of about 639-1062 m surrounding the sprayers. Similarly, higher deposition of Ca 2+ and K+ caused by the EES was detected only when deposition was assessed using nylon filters or lyophilized branches. Deposition fluxes of NO3-, NH4+ and Se were not affected by the spraying system. Techniques for measuring dry deposition and calculating landscape-level depositional loads in non-forested systems need further development. ?? 2005 Elsevier Ltd. All rights reserved.

  13. Domoic acid-induced seizures in California sea lions (Zalophus californianus) are associated with neuroinflammatory brain injury.

    PubMed

    Kirkley, Kelly S; Madl, James E; Duncan, Colleen; Gulland, Frances M; Tjalkens, Ronald B

    2014-11-01

    California sea lions (CSLs) exposed to the marine biotoxin domoic acid (DA) develop an acute or chronic toxicosis marked by seizures and act as sentinels of the disease. Experimental evidence suggests that oxidative stress and neuroinflammation are important mechanisms underlying the seizurogenic potential of environmental toxicants but these pathways are relatively unstudied in CSLs. In the current study, we investigated the role of glutamate-glutamine changes and gliosis in DA-exposed CSLs to better understand the neurotoxic mechanisms occurring during DA toxicity. Sections from archived hippocampi from control and CSLs diagnosed with DA toxicosis were immunofluorescently stained for markers of gliosis, oxidative/nitrative stress and changes in glutamine synthetase (GS). Quantitative assessment revealed increasing loss of microtubule associated protein-2 positive neurons with elevations in 4-hydroxynonenal correlating with chronicity of exposure, whereas the pattern of activated glia expressing nitric oxide synthase 2 and tumor necrosis factor followed pathological severity. There was no significant change in the amount of GS positive cells but there was increased 3-nitrotyrosine in GS expressing cells and in neurons, particularly in animals with chronic DA toxicosis. These changes were consistently seen in the dentate gyrus and in the cornu ammonis (CA) sectors CA3, CA4, and CA1. The results of this study indicate that gliosis and resultant changes in GS are likely important mechanisms in DA-induced seizure that need to be further explored as potential therapies in treating exposed wildlife. PMID:25286249

  14. Activation of an inflammatory response is context-dependent during early development of the California sea lion

    PubMed Central

    Vera-Massieu, Camila; Brock, Patrick M.; Godínez-Reyes, Carlos; Acevedo-Whitehouse, Karina

    2015-01-01

    Variations in immune function can arise owing to trade-offs, that is, the allocation of limited resources among costly competing physiological functions. Nevertheless, there is little information regarding the ontogeny of the immune system within an ecological context, and it is still unknown whether development affects the way in which resources are allocated to different immune effectors. We investigated changes in the inflammatory response during early development of the California sea lion (Zalophus californianus) and examined its association with body condition, as a proxy for the availability of energetic resources. We found that the relationship between inflammation and body condition varied according to developmental stage and circulating levels of leucocyte populations, a proxy for current infection. Body condition was related to the magnitude of the inflammatory response during two of the three developmental periods assessed, allowing for the possibility that the availability of pup energetic reserves can limit immune function. For older pups, the ability to mount an inflammatory response was related to their circulating levels of neutrophils and the neutrophil to lymphocyte ratio, implying that the infection status of an individual will influence its ability to respond to a new challenge. Our results suggest that trade-offs may occur within the immune system and highlight the importance of taking into account ontogeny in ecoimmunological studies. PMID:26064646

  15. Activation of an inflammatory response is context-dependent during early development of the California sea lion.

    PubMed

    Vera-Massieu, Camila; Brock, Patrick M; Godínez-Reyes, Carlos; Acevedo-Whitehouse, Karina

    2015-04-01

    Variations in immune function can arise owing to trade-offs, that is, the allocation of limited resources among costly competing physiological functions. Nevertheless, there is little information regarding the ontogeny of the immune system within an ecological context, and it is still unknown whether development affects the way in which resources are allocated to different immune effectors. We investigated changes in the inflammatory response during early development of the California sea lion (Zalophus californianus) and examined its association with body condition, as a proxy for the availability of energetic resources. We found that the relationship between inflammation and body condition varied according to developmental stage and circulating levels of leucocyte populations, a proxy for current infection. Body condition was related to the magnitude of the inflammatory response during two of the three developmental periods assessed, allowing for the possibility that the availability of pup energetic reserves can limit immune function. For older pups, the ability to mount an inflammatory response was related to their circulating levels of neutrophils and the neutrophil to lymphocyte ratio, implying that the infection status of an individual will influence its ability to respond to a new challenge. Our results suggest that trade-offs may occur within the immune system and highlight the importance of taking into account ontogeny in ecoimmunological studies. PMID:26064646

  16. 46. Peaks of Otter. View of the Johnson Farm, one ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    46. Peaks of Otter. View of the Johnson Farm, one of two historic structures left at peak of otter. The farm's interpretation focuses on the 1930's. Looking southeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  17. Development And Application Of A Hydrothermal Model For The Salton Sea Geothermal Field, California

    SciTech Connect

    Kasameyer, P.; Younker, L.; Hanson, J.

    1984-01-01

    A simple lateral flow model adequately explains many of the features associated with the Salton Sea Geothermal Field. Earthquake swarms, a magnetic anomaly, and aspects of the gravity anomaly are all indirect evidence for the igneous activity which is the ultimate source of heat for the system. Heat is transferred from this area of intrusion by lateral spreading of hot water in a reservoir beneath an impermeable cap rock. A two dimensional analytic model encompassing this transport mechanism matches general features of the thermal anomaly and has been used to estimate the age of the presently observed thermal system. The age is calculated by minimizing the variance between the observed surface heat-flow data and the model. Estimates of the system age for this model range from 3,000 to 20,000 years.

  18. Chemistry and geothermometry of brine produced from the Salton Sea Scientific drill hole, Imperial Valley, California

    USGS Publications Warehouse

    Thompson, J.M.; Fournier, R.O.

    1988-01-01

    The December 29-30, 1985, flow test of the State 2-14 well, also known as the Salton Sea Scientific drill hole, produced fluid from a depth of 1865-1877 m at a reservoir temperature of 305????5??C. Samples were collected at five different flashing pressures. The brines are Na-Ca-K-Cl-type waters with very high metal and low SO4 and HCO3 contents. Compositions of the flashed brines were normalized relative to the 25??C densities of the solutions, and an ionic charge balance was achieved by adjusting the Na concentration. Calculated Na/K geothermometer temperatures, using equations suggested by different investigators, range from 326?? to 364??C. The Mg/K2 method gives a temperature of about 350??C, Mg/Li2 about 282??, and Na/Li 395??-418??C. -from Authors

  19. Salton Sea Geothermal Field, Imperial Valley, California as a site for continental scientific drilling. [Abstract only

    SciTech Connect

    Elders, W.A.; Cohen, L.H.

    1983-03-01

    The Salton Trough, where seafloor spreading systems of the East Pacific Rise transition into the San Andreas transform fault system, is the site of such continental rifting and basin formation today. The largest thermal anomaly in the trough, the Salton Sea Geothermal Field (SSGF), is of interest to both thermal regimes and mineral resources investigators. At this site, temperatures >350/sup 0/C and metal-rich brines with 250,000 mg/L TDS have been encountered at <2 km depth. Republic Geothermal Inc. will drill a new well to 3.7 km in the SSGF early in 1983; we propose add-on experiments in it. If funded, we will obtain selective water and core samples and a large-diameter casing installed to 3.7 km will permit later deepening. In Phase 2, the well would be continuously cored to 5.5 km and be available for scientific studies until July 1985. The deepened well would encounter hydrothermal regimes of temperature and pressure never before sampled.

  20. Effect of Gulf of California Sea Surface Temperature on North American monsoon

    NASA Astrophysics Data System (ADS)

    Erfani, E.; Mitchell, D. L.

    2013-12-01

    The North American Monsoon (NAM) is a seasonal shift in the large-scale circulation that provides the majority of annual rainfall in northwestern Mexico and US southwest. Although regional climate models have succeeded in reproducing some characteristics of the NAM, its onset, strength and evolution are not well predicted. A physical understanding of key processes governing its life-cycle is needed to guide improvements in regional and global climate modeling of the NAM and its remote impacts on the summer circulation and precipitation patterns over North America. In this study, we propose a partial mechanistic understanding of the NAM incorporating local- and large-scale processes. The local scale mechanism explains the effect of marine boundary layer (MBL) over the northern Gulf of California (GC) using satellite observations and ship soundings launched over the GC. The strong low-level inversion capping the top of shallow MBL weakens with increasing SSTs and generally disappears once SSTs exceed 29°C, allowing the trapped MBL moisture to mix with free tropospheric air. This leads to a deep, moist, well-mixed layer that can be transported inland by favorable low-level jets to form thunderstorms in Arizona and elsewhere. The large-scale mechanism relates tropical surface water, tropospheric moisture and the NAM anticyclone by means of climatologies of satellite SST, outgoing longwave radiation (OLR) and NCEP/NCAR reanalysis of 500 hPa geopotential height from 1983 to 2010. As warm Pacific SSTs propagate northwards up the Mexican coastline, deep convection follows this northward advance, with associated descending air north/northeast of the convection region possibly advancing the position of the anticyclone. This evolution brings mid-level tropical moisture into the NAM region. A set of carefully designed simulations of WRF is used to investigate the dependence of NAM precipitation, onset and circulation on SSTs along the Mexican coastline and in the GC. North

  1. Radar measurement of forested areas during OTTER

    NASA Technical Reports Server (NTRS)

    Moghaddam, M.; Durden, S.; Zebker, H.; Klein, J.

    1992-01-01

    To test a forest ecosystem model in the OTTER (Oregon ecosystem research) project, it is desirable to find forest canopy parameters via radar remote sensing measurements. Conventionally, forest biomass, along with quantities such as the leaf area index, drive the model. It is shown that the radar backscatter is not uniquely related to biomass. A sensitivity study is carried out using a forward scattering model to determine the variation of radar cross section as a function of several forest parameters. The results are used to find suitable quantities to recover via radar experiments. A parameter estimation scheme is developed to calculate some preliminary statistical properties of the forest.

  2. Health status, infection and disease in California sea lions (Zalophus californianus) studied using a canine microarray platform and machine-learning approaches.

    PubMed

    Mancia, Annalaura; Ryan, James C; Chapman, Robert W; Wu, Qingzhong; Warr, Gregory W; Gulland, Frances M D; Van Dolah, Frances M

    2012-04-01

    Conservation biologists face many challenges in assessing health, immune status and infectious diseases in protected species. These challenges include unpredictable sample populations, diverse genetic and environmental backgrounds of the animals, as well as the practical, legal and ethical issues involved in experimentation. The use of whole genome scale transcriptomics with animal samples obtained in a minimally invasive manner is an approach that shows promise for health assessment. In this study we assessed the utility of a microarray to identify changes in gene expression predictive of health status by interrogating blood samples from California sea lions (Zalophus californianus) in rehabilitation. A custom microarray was developed from the commercially available dog microarray (Canis familiaris) by selecting probes that demonstrated reliable cross-hybridization with RNA in sea lion blood. This custom microarray was used for the analysis of RNA from 73 sea lion blood samples, from animals with a broad spectrum of health changes. Both traditional classifying techniques and newer artificial neural network approaches correctly classified sea lions with respect to health status, primarily distinguishing between leptospirosis infection and domoic acid exposure. Real time PCR validation for a small set of genes, followed by sequencing, showed good correlation with array results and high identity (96-98%) between the dog and sea lion sequences. This approach to health status classification shows promise for disease identification in a clinical setting, and assessment of health status of wildlife. PMID:22067742

  3. Heavy metal concentrations in tissues of Virginia river otters

    SciTech Connect

    Anderson-Bledsoe, K.L.; Scanlon, P.F.

    1983-04-01

    Concentrations of lead, cadmium, zinc and copper in liver, kidney and bone samples of otter harvested during the 1979-1980 and 1980-1981 trapping seasons were determined by atomic absorption spectrophotometry. Correlations between metal concentrations and age for all three tissues were nonsignificant. Correlations among the concentrations of the four elements in liver and kidney samples were also nonsignificant for otter samples in both years. The highest correlation coefficient (0.47) was found between zinc and copper concentrations in liver samples from otters trapped during the 1979-1980 trapping season. (JMT)

  4. OTTER 3.0 reference manual and guide

    SciTech Connect

    McCune, W.W.

    1994-01-01

    OTTER (Organized Techniques for Theorem-proving and Effective Research) is a resolution-style theorem-proving program for first-order logic with equality. OTTER includes the inference rules binary resolution, hyperresolution, UR-resolution, and binary paramodulation. Some of its other abilities and features are conversion from first-order formulas to clauses, forward and back subsumption, factoring, weighting, answer literals, term ordering, forward and back demodulation, evaluable functions and predicates, and Knuth-Bendix completion. OTTER is coded in C, is free, and is portable to many different kinds of computer.

  5. 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.

  6. Cesium-137 levels detected in Georgia otters

    SciTech Connect

    Halbrook, R.S.; Jenkins, J.H.

    1988-11-01

    Beginning in the 1940's and continuing through the 50's and early 60's, nuclear devices were tested by aerial detonation in the United States and other countries around the world. Cesium-137 (/sup 137/Cs) is one of the most important radionuclide by-products due to its abundance and slow decay (30-year half-life). The uptake of /sup 137/Cs in animal tissue is the result of its similarity to potassium. The somatic and genetic effects of /sup 137/Cs, along with its effect on reproductive cells, can pose great hazards to wildlife species. A reported buildup of /sup 137/Cs in white-tailed deer in the lower coastal plain of Georgia during the 1960's was followed by a gradual decline during the 1970's. Although numerous studies have involved terrestrial mammals of Georgia, few have involved aquatic mammals such as the river otter. With continued atmospheric testing by some foreign countries and the increased use of nuclear power as an energy source, there is a need for continued monitoring of radionuclides in wildlife to ascertain the quality of the environment. This study was initiated as part of an overall study of environmental pollutants in the river otter of Georgia and deals with analysis of the /sup 137/Cs accumulations in this species.

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

    USGS Publications Warehouse

    Bodkin, J.L.; Jameson, R.

    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 mammlas. 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 Nino-Southern Oscillation (ENSO) of 1982-1983 was the dominate influence in terms of interannual variation in carcassdeposition. During this ENSO, 56% of the seabirds and 48% of the marine mammals washed ashore. Patterns of intra-annual variation were species specificand 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 subtrate type and local patterns of san deposition influenced the location of carcass 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 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.

  8. A multi-trial diagnostic tool in fin whale (Balaenoptera physalus) skin biopsies of the Pelagos Sanctuary (Mediterranean Sea) and the Gulf of California (Mexico).

    PubMed

    Fossi, Maria Cristina; Urban, Jorge; Casini, Silvia; Maltese, Silvia; Spinsanti, Giacomo; Panti, Cristina; Porcelloni, Serena; Panigada, Simone; Lauriano, Giancarlo; Niño-Torres, Carlos; Rojas-Bracho, Lorenzo; Jimenez, Begoña; Muñoz-Arnanz, Juan; Marsili, Letizia

    2010-01-01

    The main objective of this study was to apply a set of sensitive non-lethal biomarkers in skin biopsies of fin whales (Balaenoptera physalus) to evaluate the toxicological status of this mysticete in the Pelagos Sanctuary (Mediterranean Sea) and in the Gulf of California (Sea of Cortez-Mexico). We developed a "multi-trial diagnostic tool" (based on field and in vitro studies), combining molecular biomarkers (western blot of CYP1A1, CYP2B) and gene expression (qRT-PCR of HSP70, ERα, AHR, E2F-1) with the analysis of OCs, PAHs and PBDEs. The study revealed a higher level of toxicological stress in the Mediterranean fin whales. PMID:19913904

  9. The Obsidian Creep Project: Seismic Imaging in the Brawley Seismic Zone and Salton Sea Geothermal Field, Imperial County, California

    NASA Astrophysics Data System (ADS)

    Catchings, R. D.; Rymer, M. J.; Goldman, M.; Lohman, R. B.; McGuire, J. J.

    2010-12-01

    In March 2010, we acquired medium- and high-resolution P- and S-wave seismic reflection and refraction data across faults in the Brawley seismic zone (BSZ) and across part of the Salton Sea Geothermal Field (SSGF), Imperial Valley, California. Our objectives were to determine the dip, possible structural complexities, and seismic velocities associated with the BSZ and SSGF. We acquired multiple seismic data sets along a north-south profile and a high-resolution P-wave profile along an east-west profile. The north-south profile included: 1) a 6.4-km-long P-wave (main) profile that was recorded on 320 Texan seismographs spaced at 20-m intervals, 2) a 1.2-km-long cabled, high-resolution profile along the northern end of the main profile, and 3) an approximately 1.2-km-long S-wave profile along the cabled profile. P-wave sources along the main profile were generated by 0.15- to 0.45-kg buried explosions spaced every 40 m, and P-wave sources along the cabled profile were generated by Betsy-Seisgun ‘shots’ spaced every 10 m. S-waves sources were generated by hammer impacts on the ends of an aluminum block. The east-west profile consisted of a 3.4-km-long high-resolution P-wave seismic profile with shots (Betsy-Seisgun) and geophones spaced every 10 m. Preliminary interpretation of shot gathers from blasts in the north-south profile suggests that the BSZ and SSGF are structurally complex, with abundant faults extending to or near the ground surface. Also, we observe relatively high-velocity material, apparent velocities of about 4.0 km/s in one direction and about 2.8 km/s in another relative to about 1.6 km/s for shallower material, that shallows beneath the SSGF. This may be due to high temperatures and resultant metamorphism of buried materials in the SSGF. From preliminary interpretation of shot gathers along the east-west profile we interpret a prominent fault that extends to the ground surface. This fault is on projection of the Kalin fault, from about 40 m to

  10. 27. Otter Creek Bridge #5. Detail of the interior abutment ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. Otter Creek Bridge #5. Detail of the interior abutment wall. Wingwall, and facade thickness. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  11. 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

  12. Fluid origin, gas fluxes and plumbing system in the sediment-hosted Salton Sea Geothermal System (California, USA)

    NASA Astrophysics Data System (ADS)

    Mazzini, Adriano; Svensen, Henrik; Etiope, Giuseppe; Onderdonk, Nathan; Banks, David

    2011-08-01

    The Salton Sea Geothermal System (California) is an easily accessible setting for investigating the interactions of biotic and abiogenic geochemical processes in sediment-hosted hydrothermal systems. We present new temperature data and the molecular and isotopic composition of fluids seeping at the Davis-Schrimpf seep field during 2003-2008. Additionally, we show the first flux data for CO 2 and CH 4 released throughout the field from focused vents and diffuse soil degassing. The emitted gases are dominated by CO 2 (~ 98%) and CH 4 (~ 1.5%). By combining δ 13C CO2 (as low as - 5.4‰) and δ 13C CH4 (- 32‰ to - 17.6‰) with 3He/ 4He (R/Ra > 6) and δD CH4 values (- 216‰ to - 150‰), we suggest, in contrast to previous studies, that CO 2 may have a significant Sub-Continental Mantle source, with minimal crustal contamination, and CH 4 seems to be a mixture of high temperature pyrolitic (thermogenic) and abiogenic gas. Water seeps show that δD and δ 18O increase proportionally with salinity (Total Dissolved Solids in g/L) ranging from 1-3 g/L (gryphons) to 145 g/L (hypersaline pools). In agreement with elemental analyses, the isotopic composition of the waters indicate a meteoric origin, modified by surface evaporation, with little or no evidence of deep fossil or magmatic components. Very high Cl/Br (> 3,000) measured at many seeping waters suggests that increased salinities result from dissolution of halite crusts near the seep sites. Gas flux measurements from 91 vents (pools and gryphons) give a conservative estimate of ~ 2,100 kg of CO 2 and 11.5 kg of CH 4 emitted per day. In addition soil degassing measured at 81 stations (20x20 m grid over 51,000 m 2) revealed that 7,310 kg/d CO 2 and 33 kg/d CH 4 are pervasively released to the atmosphere. These results emphasise that diffuse gas emission from soil can be dominant (~ 75%) even in hydrothermal systems with large and vigorous gas venting. Sediment-hosted hydrothermal systems may represent an

  13. Attendance patterns of California sea lion (Zalophus californianus) females and pups during the non-breeding season at San Miguel Island

    USGS Publications Warehouse

    Melin, S.R.; DeLong, R.L.; Thomason, J.R.; VanBlaricom, G.R.

    2000-01-01

    The attendance patterns of California sea lions were studied during the non-breeding seasons from 1991 to 1994. Lactating females frequented the rookery to nurse their pups until weaning; most non-lactating females left the rookery for the season. Females spent over 70% of their time at sea except in 1993 when they spent 59% of their time at sea. The mean foraging trip length in the winter and spring ranged from 3.3 to 4.6 d; the mean nursing visit ranged from 1.2 to 1.4 d. The duration of foraging trips and nursing visits was variable over the season for individuals but no pattern of change was detected. Interannual and seasonal differences were not significant for time at sea, visits ashore, or foraging-trip duration before, during, or after the 1992-1993 El Nino event. Pups spent an average of 66.6% of their time ashore and up to three days away from the rookery during their mother's absence. Most females and pups stayed associated until April or May. The results suggest that seasonal movement of prey is more important in determining attendance patterns late in the lactation period than increasing energy demands of the pup.

  14. Relationships between organochlorine concentrations in liver and muscle of otters

    SciTech Connect

    Mason, C.F. )

    1989-10-01

    The European otter (Lutra lutra) is now threatened or endangered over much of its European range. The decline, which has taken place mainly during the past three decades, has been attributed to the toxic effects of organochlorine residues, with emphasis being placed on dieldrin or PCBs. Few otters were analyzed for organochlorines during the main period of decline but there is not considerable interest in the species. Experiments with ranch mink (Mustela vison) have shown that reproductive failure occurs when PCB concentrations in thigh muscle approach 50 mg kg{sup {minus}1} lipid. Because otters are closely related and have similar habits this value is becoming widely used to interpret the potential significance of PCB concentrations determined in otters. Furthermore, although the mink data refer to concentrations in muscle, interpretations of concentrations in otters have frequently been based on analyses of livers. Because of the diverse sources of material in Europe, only limited tissues may be made available for analysis, while costs may also prohibit the analysis of several tissues from a single carcass. The relationship between concentrations of organochlorines in muscle and liver tissues in otters has not been determined. This is the purpose of the present communication.

  15. Biomarker responses in river otters experimentally exposed to oil contamination.

    PubMed

    Ben-David, M; Duffy, L K; Bowyer, R T

    2001-07-01

    Investigations in Prince William Sound (Alaska, USA) following the Exxon Valdez oil spill (EVOS) revealed that river otters (Lontra canadensis) on oiled shores had lower body mass and elevated values of biomarkers, than did otters living on nonoiled shores. In addition, otters from oiled areas selected different habitats, had larger home ranges, and less diverse diets than animals living in nonoiled areas. These differences between river otters from oiled shores and those from nonoiled areas strongly suggested that oil contamination had an effect on physiological and behavioral responses of otters. In this study, we explored the effects of crude oil contamination on river otters experimentally. We hypothesized that exposure to oil would result in elevated values of biomarkers, indicating induced physiological stress. Fifteen wild-caught male river otters were exposed to two levels of weathered crude oil (i.e., control, 5 ppm/day/kg body mass, and 50 ppm/day/kg body mass) under controlled conditions in captivity at the Alaska Sealife Center in Seward (Alaska, USA). Responses of captive river otters to oil ingestion provided mixed results in relation to our hypotheses. Although hemoglobin (Hb, and associated red blood cells) and white blood cells, and possibly interleukin-6 immunoreactive responded in the expected manner, other parameters did not. Aspartate aminotransferase, alanine aminotransferase, and haptoglobin (Hp), did not increase in response to oiling or decreased during rehabilitation. Conversely, principle-component analysis identified values of alkaline phosphatase as responding to oil ingestion in river otters. Our results suggested that opposing processes were concurring in the oiled otters. Elevated production of Hp in response to tissue damage by hydrocarbons likely occurred at the same time with increased removal of Hp-Hb complex from the serum, producing an undetermined pattern in the secretion of Hp. Thus, the use of individual biomarkers as

  16. 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.

  17. Proteomic Analysis of Plasma from California Sea Lions (Zalophus californianus) Reveals Apolipoprotein E as a Candidate Biomarker of Chronic Domoic Acid Toxicosis

    PubMed Central

    Neely, Benjamin A.; Ferrante, Jason A.; Chaves, J. Mauro; Soper, Jennifer L.; Almeida, Jonas S.; Arthur, John M.; Gulland, Frances M. D.; Janech, Michael G.

    2015-01-01

    Domoic acid toxicosis (DAT) in California sea lions (Zalophus californianus) is caused by exposure to the marine biotoxin domoic acid and has been linked to massive stranding events and mortality. Diagnosis is based on clinical signs in addition to the presence of domoic acid in body fluids. Chronic DAT further is characterized by reoccurring seizures progressing to status epilepticus. Diagnosis of chronic DAT is often slow and problematic, and minimally invasive tests for DAT have been the focus of numerous recent biomarker studies. The goal of this study was to retrospectively profile plasma proteins in a population of sea lions with chronic DAT and those without DAT using two dimensional gel electrophoresis to discover whether individual, multiple, or combinations of protein and clinical data could be utilized to identify sea lions with DAT. Using a training set of 32 sea lion sera, 20 proteins and their isoforms were identified that were significantly different between the two groups (p<0.05). Interestingly, 11 apolipoprotein E (ApoE) charge forms were decreased in DAT samples, indicating that ApoE charge form distributions may be important in the progression of DAT. In order to develop a classifier of chronic DAT, an independent blinded test set of 20 sea lions, seven with chronic DAT, was used to validate models utilizing ApoE charge forms and eosinophil counts. The resulting support vector machine had high sensitivity (85.7% with 92.3% negative predictive value) and high specificity (92.3% with 85.7% positive predictive value). These results suggest that ApoE and eosinophil counts along with machine learning can perform as a robust and accurate tool to diagnose chronic DAT. Although this analysis is specifically focused on blood biomarkers and routine clinical data, the results demonstrate promise for future studies combining additional variables in multidimensional space to create robust classifiers. PMID:25919366

  18. Proteomic Analysis of Plasma from California Sea Lions (Zalophus californianus) Reveals Apolipoprotein E as a Candidate Biomarker of Chronic Domoic Acid Toxicosis.

    PubMed

    Neely, Benjamin A; Ferrante, Jason A; Chaves, J Mauro; Soper, Jennifer L; Almeida, Jonas S; Arthur, John M; Gulland, Frances M D; Janech, Michael G

    2014-01-01

    Domoic acid toxicosis (DAT) in California sea lions (Zalophus californianus) is caused by exposure to the marine biotoxin domoic acid and has been linked to massive stranding events and mortality. Diagnosis is based on clinical signs in addition to the presence of domoic acid in body fluids. Chronic DAT further is characterized by reoccurring seizures progressing to status epilepticus. Diagnosis of chronic DAT is often slow and problematic, and minimally invasive tests for DAT have been the focus of numerous recent biomarker studies. The goal of this study was to retrospectively profile plasma proteins in a population of sea lions with chronic DAT and those without DAT using two dimensional gel electrophoresis to discover whether individual, multiple, or combinations of protein and clinical data could be utilized to identify sea lions with DAT. Using a training set of 32 sea lion sera, 20 proteins and their isoforms were identified that were significantly different between the two groups (p<0.05). Interestingly, 11 apolipoprotein E (ApoE) charge forms were decreased in DAT samples, indicating that ApoE charge form distributions may be important in the progression of DAT. In order to develop a classifier of chronic DAT, an independent blinded test set of 20 sea lions, seven with chronic DAT, was used to validate models utilizing ApoE charge forms and eosinophil counts. The resulting support vector machine had high sensitivity (85.7% with 92.3% negative predictive value) and high specificity (92.3% with 85.7% positive predictive value). These results suggest that ApoE and eosinophil counts along with machine learning can perform as a robust and accurate tool to diagnose chronic DAT. Although this analysis is specifically focused on blood biomarkers and routine clinical data, the results demonstrate promise for future studies combining additional variables in multidimensional space to create robust classifiers. PMID:25919366

  19. 78 FR 26771 - Otter Creek Solar LLC; Notice of Petition for Enforcement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ... Energy Regulatory Commission Otter Creek Solar LLC; Notice of Petition for Enforcement Take notice that on May 1, 2013, Otter Creek Solar LLC (Otter Creek) filed a Petition for Enforcement, pursuant to... regulations and in violation of the Federal Power Act. Any person desiring to intervene or to protest...

  20. 78 FR 62361 - Green Mountain Power Corporation; Vermont; Otter Creek Hydroelectric Project; Notice of Proposed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-21

    ... Energy Regulatory Commission Green Mountain Power Corporation; Vermont; Otter Creek Hydroelectric Project... that could be affected by issuance of a new license for the Otter Creek Hydroelectric Project No. 2558..., as applicant for the Otter Creek Hydroelectric Project, has expressed an interest in this...

  1. Final Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin, California

    USGS Publications Warehouse

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2010-01-01

    This report summarizes comprehensive findings from a 4-year-long field investigation to document baseline environmental conditions in 29 agricultural drains and ponds operated by the Imperial Irrigation District along the southern border of the Salton Sea. Routine water-quality collections and fish community assessments were conducted on as many as 16 sampling dates at roughly quarterly intervals from July 2005 to April 2009. The water-quality measurements included total suspended solids and total (particulate plus dissolved) selenium. With one exception, fish were surveyed with baited minnow traps at quarterly intervals during the same time period. However, in July 2007, fish surveys were not conducted because we lacked permission from the California Department of Fish and Game for incidental take of desert pupfish (Cyprinodon macularius), an endangered species. During April and October 2006-08, water samples also were collected from seven intensively monitored drains (which were selected from the 29 total drains) for measurement of particulate and dissolved selenium, including inorganic and organic fractions. In addition, sediment, aquatic food chain matrices [particulate organic detritus, filamentous algae, net plankton, and midge (chironomid) larvae], and two fish species (western mosquitofish, Gambusia affinis; and sailfin molly, Poecilia latipinna) were sampled from the seven drains for measurement of total selenium concentrations. The mosquitofish and mollies were intended to serve as surrogates for pupfish, which we were not permitted to sacrifice for selenium determinations. Water quality (temperature, dissolved oxygen, pH, specific conductance, and turbidity) values were typical of surface waters in a hot, arid climate. A few drains exhibited brackish, near-anoxic conditions, especially during summer and fall when water temperatures occasionally exceeded 30 degrees Celsius. Total selenium concentrations in water were directly correlated with salinity and

  2. The Impacts of Back-Beach Barriers on Sandy Beach Morphology Along the California Coast and Implications for Coastal Change with Future Sea-Level Rise

    NASA Astrophysics Data System (ADS)

    Harden, E. L.

    2010-12-01

    Coastal squeeze, or foreshore narrowing, is a result of marine encroachment, such as sea-level rise in the presence of a back-beach barrier, terrestrial encroachment, such as coastal development, or both. In California, the permanent coastal population increased by almost 10 million people between 1980 and 2003, and an additional 130 million beachgoers visit Southern California beaches each year. Beaches in California are an important component of the state and federal economy and provide hundreds of thousands of jobs. Approximately 14% of the California coast from Marin County to the Mexican border is artificially armored with seawalls, rip rap, or revetment, more than half of which protects back-beach developments or lower-lying dynamic regions like harbors and dunes. Many sandy beaches that do not have back-beach armoring are still restricted by commercial and residential infrastructure, parking lots, and roadways. Although these types of coastal infrastructure are not back-beach barriers by intentional design like seawalls and rip rap, they still restrict beaches from landward migration and can cause significant placement loss of the beach. Nearly 67 km, or 44% of the total length of sandy coastline from Long Beach to the U.S.-Mexico border is backed by such infrastructure. This study is part of a broader effort to catalog the extent to which California’s beaches are restricted in the back beach, to describe the effects of back-beach barriers on sandy beach morphology, and to predict how these different beaches might behave with future sea-level rise. Beach morphology, shoreface characteristics, and historical rates of shoreline change were compared between select beaches with back-beach barriers and unrestricted beaches using 1997 LiDAR data and shoreline rates of change published in the U.S. Geological Survey’s National Assessment of Shoreline Change report. Although preliminary results of the morphological analysis show that there is no statistically

  3. Late Quaternary sea-level history and the antiquity of mammoths (Mammuthus exilis and Mammuthus columbi), Channel Islands National Park, California, USA

    NASA Astrophysics Data System (ADS)

    Muhs, Daniel R.; Simmons, Kathleen R.; Groves, Lindsey T.; McGeehin, John P.; Randall Schumann, R.; Agenbroad, Larry D.

    2015-05-01

    Fossils of Columbian mammoths (Mammuthus columbi) and pygmy mammoths (Mammuthus exilis) have been reported from Channel Islands National Park, California. Most date to the last glacial period (Marine Isotope Stage [MIS] 2), but a tusk of M. exilis (or immature M. columbi) was found in the lowest marine terrace of Santa Rosa Island. Uranium-series dating of corals yielded ages from 83.8 ± 0.6 ka to 78.6 ± 0.5 ka, correlating the terrace with MIS 5.1, a time of relatively high sea level. Mammoths likely immigrated to the islands by swimming during the glacial periods MIS 6 (~ 150 ka) or MIS 8 (~ 250 ka), when sea level was low and the island-mainland distance was minimal, as during MIS 2. Earliest mammoth immigration to the islands likely occurred late enough in the Quaternary that uplift of the islands and the mainland decreased the swimming distance to a range that could be accomplished by mammoths. Results challenge the hypothesis that climate change, vegetation change, and decreased land area from sea-level rise were the causes of mammoth extinction at the Pleistocene/Holocene boundary on the Channel Islands. Pre-MIS 2 mammoth populations would have experienced similar or even more dramatic changes at the MIS 6/5.5 transition.

  4. Late Quaternary sea-level history and the antiquity of mammoths (Mammuthus exilis and Mammuthus columbi), Channel Islands NationalPark, California, USA

    USGS Publications Warehouse

    Muhs, Daniel R.; Simmons, Kathleen R.; Groves, Lindsey T.; McGeehin, John P.; Schumann, R. Randall; Agenbroad, Larry D.

    2015-01-01

    Fossils of Columbian mammoths (Mammuthus columbi) and pygmy mammoths (Mammuthus exilis) have been reported from Channel Islands National Park, California. Most date to the last glacial period (Marine Isotope Stage [MIS] 2), but a tusk of M. exilis (or immature M. columbi) was found in the lowest marine terrace of Santa Rosa Island. Uranium-series dating of corals yielded ages from 83.8 ± 0.6 ka to 78.6 ± 0.5 ka, correlating the terrace with MIS 5.1, a time of relatively high sea level. Mammoths likely immigrated to the islands by swimming during the glacial periods MIS 6 (~ 150 ka) or MIS 8 (~ 250 ka), when sea level was low and the island–mainland distance was minimal, as during MIS 2. Earliest mammoth immigration to the islands likely occurred late enough in the Quaternary that uplift of the islands and the mainland decreased the swimming distance to a range that could be accomplished by mammoths. Results challenge the hypothesis that climate change, vegetation change, and decreased land area from sea-level rise were the causes of mammoth extinction at the Pleistocene/Holocene boundary on the Channel Islands. Pre-MIS 2 mammoth populations would have experienced similar or even more dramatic changes at the MIS 6/5.5 transition.

  5. Movement and diving behavior of male California sea lion (Zalophus californianus) during anomalous oceanographic conditions of 2005 compared to those of 2004

    NASA Astrophysics Data System (ADS)

    Weise, Michael J.; Costa, Daniel P.; Kudela, Raphael M.

    2006-11-01

    During the highly anomalous conditions in early 2005, characterized by increased water temperatures and decreased productivity, male California sea lions adopted previously undocumented foraging behaviors. We investigated the movement and spatially explicit foraging behavior of males using satellite-linked data loggers and compared foraging behavior and effort between 2003-2004 and 2004-2005. Males foraged almost exclusively over the continental shelf during short trips in 2003-2004, while during anomalous conditions in 2004-2005 they altered their foraging effort by spending more time at sea and venturing up to 450 km offshore. Foraging trips in 2004-2005 were more than twice the distance and three times the duration of trips during 2003-2004. Our data indicated that the effects of climatic shifts during 2005 extended beyond the physical oceanography and lower trophic levels, to an apex predator; providing insight into the plasticity of foraging behavior and movement patterns of sea lions as they respond to environmental perturbations.

  6. 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. PMID:26131525

  7. University of California Sea Grant College Program, Annual Report 1972-1973. September 1, 1972 to August 31, 1973.

    ERIC Educational Resources Information Center

    Cummings, Maynard W.; And Others

    Presented in this 1972-1973 annual report are summaries of projects in advisory services, coastal zone studies, fisheries and aquaculture, marine products, and ocean engineering. A listing of publications and an activity budget are included. The report is intended to be a general overview of the total activities of the University of California's…

  8. Landslides: Geomorphology and Sea Cliff Hazard Potential, Santa Barbara - Isla Vista, California J.F. Klath and E.A. Keller

    NASA Astrophysics Data System (ADS)

    Klath, J. F.; Keller, E. A.

    2015-12-01

    sea level rise estimates, a map displaying likely position of the coastline by 2100 will be created. This information will be useful to the county of Santa Barbara, California when considering future development and hazard mitigation plans.

  9. Spatial and temporal assessment of environmental contaminants in water, sediments and fish of the Salton Sea and its two