Dissertations / Theses: 'Otariid'

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Browne, Patience. "Some aspects of the reproductive physiology of otariid pinnipeds /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.

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Thesis (Ph. D.)--University of California, Davis, 2004.
Degree granted in Molecular, Cellular, and Integrative Physiology. Includes bibliographical references. Also available via the World Wide Web. (Restricted to UC campuses)

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Sanfelice, Daniela. "Ontogenia craniana comparada de Arctocephalus australis, Callorhinus ursinus e Otaria byronia (Otariidae: Pinnipedia)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2003. http://hdl.handle.net/10183/15623.

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The search for mechanisms that can generate major morphological changes has led to the study of ontogeny, in part because some kinds of modifications of ontogenies seem an excelent way to generate major phenotypic change. We focus here on Arctocephlaus australis, Callorhinus ursinus and Otaria byronia with the aim of contributing to the understanding of the origin, structure and temporal patterns of otarid morphological diversity. The pattern of change in shape during postnatal development in otarid skull was studied and described by geometric and traditional morphometrics. Our aims are: to compare the skull ontogeny of the species invocated in identifying and in describing shape alterations in the skull; to evaluate and to describe comparatively the sexual dimorphism and disparity during the ontogeny; to study the covariance between size and shape in relationship with age-groups; to investigate the changes in the ontogeny and their relationships with the evolution of the Otariidae Family; to analyze the conservation of ontogenetic trajectories over time, between sexes and among species; to characterize growth trajectories and to compare them among taxa with respect to isometry; to describe the parameters of growth and development of the focused species and to compare the two different approaches employed. Using traditional morphometrics, the allometry vectors for all species were significantly different from isometry. Dimorphism in the allometric vector is observed only in O. byonia and the difference between males and females of the fur seals are related with adult body size. The comparisons species/sex groups revealed similar vectors (any significant shape disassociation are verified in the inter-specific analyzes), suggesting lower plasticity of the ontogenies. Using geometrical methods, the dimorphism is more conspicuous in adult shapes but this is not true for the level of disparity between sexes of O. byronia. Although that dimorphism is linked with size this is not only a question of scaling or allometry (which is present in the morphogenesis of all species, especially in O. byronia). Additionally, the slopes of changes in shape related with size increase are different in A. australis and O. byronia, but are equal in C. ursinus, which is the smaller species. We suggest post-displacement as one of the factors that could have acted in the origin of the sexual dimorphism in the skull of C. ursinus. Heterochrony, perhaps is present in the roots of the modifications suffered by the ontogeny of A. australis and O. byronia too, considering the differences in the rates of development between the sexes of both species (and overall in O. byronia), but surely repatterning allometric is involved too in these cases. We verified that ontogenies can not be summarized by a single linear vector in any analyzed group, where C. ursinus ontogeny is the more linear and O. byronia the more multi-dimensional species among the 3 that we had examined. Shape changes in the otarids studied here are more related with size than with age and any of the species share a common growth allometry or a common ontogenetic trajectory/pattern. In the same way, shapes at onset or offset are not the same in any case. When the three species are pooled together, initial shapes are always very different among the species and the distances between shapes increase with time almost independently from size. On the other hand, when the complete samples are considered, all the ontogenetic trajectories are significantly different in the directions of the allometric vectors during ontogeny. Ontogenetic trajectories differ significantly among almost all the pairs compared, except for the trajectories of A. australis and C. ursinus males. They are no more different than expected by chance considering the range of angles within each sample. A similar pattern is found when the subadults are compared between pairs of species and when we compare adult males of A. australis with adult males of O. byronia. The juveniles are no more different than expected by chance (correlation between ontogenies in that phase is equal to one), excepti between C. ursinus and O. byronia. The ontogenetic trajectory of C. ursinus is the shorter and of O. byronia is the longer being almost three times longer than the former. A. australis has an intermediary length of ontogenetic trajectory. For the sample comprising all three species disparity increase significantly over ontogeny since the disparity of the adults is near the two times of the disparity between juveniles. For any ontogenetic stage, O. byronia is the species that contributes for the disparity of the all group, followed by C. ursinus. When we consider the three species together, the pattern of disparity do not change a lot during ontogeny. Ontogenies examined herein are clearly not constrained and perhaps the differences in patterns have additive effects in the differentiation of the ontogenies. Whether ontogenetic trajectories are linear or curve could be a function of developmental timing or more specifically it could depend on the age at which allometries stabilize in post-natal ontogenies. Otherwise, the amount of differences between species in the ontogenies is in agreement with the phylogenetic relationships. Finally, we addressed basically the following questions: Is onset time the same in the species? Is offset time the same in these species? Does growth rate differ between the species. The answer to those questions could be summarized by the conclusion. but we conclude that the changes in otarids skull ontogenies had occurred in spatial and temporal terms.

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Drehmer, César Jaeger. "Variação geográfica em Otaria byronia (de Blainville, 1820) (Pinnipedia, Otariidae) com base na morfometria sincraniana." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/8135.

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Otaria byronia (de Blainville, 1820), o leão-marinho sul-americano é uma espécie de otarídeo amplamente distribuída pela costa da América do Sul. No oceano Atlântico estende-se desde o sul do Brasil, passando pelo Uruguai até o sul da Argentina e no oceano Pacífico, ao longo das costas do Chile e do Peru. Estudos prévios indicam a possibilidade de existência de diferenças geográficas entre as unidades populacionais dessa espécie. No presente trabalho objetiva-se identificar a existência de variação geográfica e avaliar a intensidade da mesma. Para tal, utilizou-se a morfometria sincraniana com base em morfometria tradicional – 41 medidas abrangendo o crânio e o dentário e também a técnica da morfometria geométrica com base na configuração de marcos anatômicos para quatro vistas distintas – dorsal, palatal, lateral e mandibular medial. Utilizaram-se apenas espécimes adultos identificados através do comprimento côndilo-basal. Machos e fêmeas foram tratados separadamente devido ao intenso dimorfismo sexual na morfologia sincraniana. Utilizaram-se inicialmente testes t para identificar diferenças entre os grupos, dividindo-os de acordo com a distribuição geográfica das unidades populacionais, gerando um total de 4: Atlântico Segmento I (Sul do Brasil Uruguai e província de Buenos Aires), Atlântico Segmento II (Patagônia da Argentina), Pacífico Segmento I (Peru) e Pacífico Segmento II (Chile). Através de uma ANOVA sobre as medidas tradicionais e sobre o tamanho do centróide, bem como de uma MANOVA sobre a configuração de marcos anatômicos, foi possível identificar diferenças nas médias desses quatro grupos. Caracterizou-se uma forte variação geográfica, onde a variação entre os grupos sempre foi maior do que a variação dentro dos grupos. As diferenças entre os grupos de fêmeas do Pacífico são maiores do que as diferenças entre os grupos do Atlântico; já em machos as diferenças entre os grupos do Pacífico foram menores do que entre os grupos do Atlântico. Quando analisados em conjunto os dados das unidades populacionais do Pacífico em comparação com o Atlântico, estas diferenças permanecem. Utilizando técnicas exploratórias como Análise de Componentes Principais e Análise Discriminante, tanto para morfometria tradicional quanto para morfometria geométrica, foi possível caracterizar as unidades populacionais de forma mais consistente, bem como mensurar as diferenças entre estas. Os resultados obtidos confirmam as diferenças encontradas nas análises anteriores. A morfometria craniana indica a existência de quatro unidades populacionais para Otaria byronia, duas no Pacífico e duas no Atlântico, sem que haja isolamento geográfico entre estes grupos, uma vez que tanto a corrente das Malvinas no Atlântico como a corrente de Humboldt no Pacífico são grandes vias de deslocamento entre estas unidades populacionais, bem como o extremo-sul da América do Sul no qual os canais do Estreito de Magalhães não devem ser barreira para o intercâmbio, ainda que limitado, de indivíduos entre os oceanos. Este intercâmbio está diretamente relacionado com a capacidade de dispersão de machos e fêmeas e com aspectos da dinâmica populacional desta espécie. Algumas limitações, entretanto, impedem que se avance em direção a alguma conclusão taxonômica em nível de subespécies, embora a craniometria esteja a indicar uma clara tendência à separação das unidades populacionais, especialmente quando comparadas as do Atlântico com as do Pacífico.

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Verrier, Delphine. "Extreme fasting in subantartic fue seal (Arctocephalus tropicalis) pups : Physiological adaptations and ecological implications." Université Louis Pasteur (Strasbourg) (1971-2008), 2007. http://www.theses.fr/2007STR13197.

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Ce travail examine les adaptations énergétiques, métaboliques, hormonales et comportementales mises en oeuvre lors des jeûnes répétés et prolongés auxquels le petit de l'Otarie d'Amsterdam doit faire face au cours de ses dix mois de croissance. Une attention particulière est portée à l'ontogénèse de ces adaptations. Le rôle clef de l'épargne énergétique et du stockage de réserves lipidiques est mis en évidence, de même qu'une très forte épargne des protéines corporelles qui ne contribuent qu'à 2% de la dépense d'énergie lors du jeûne. Parmi les différentes hormones considérées (hormones thyroïdiennes, cortisol, glucagon, insuline et leptine), le rôle de la leptine comme médiateur de l'adaptation au jeûne est pour la première fois mis en évidence chez un animal sauvage (autre que primates et rongeurs). Les capacités de résistance au jeûne augmentent avec l'âge, grâce à une réduction de la dépense énergétique et de l'activité comportementale, et aussi suite à une optimisation du niveau d'épargne protéique associée à une augmentation de l'adiposité. L'ensemble des résultats permet de comprendre comment les stratégies alimentaires maternelles pourraient être contraintes par ces changements ontogéniques de la tolérance au jeûne du petit. En outre, les compromis dévelopementaux imposés par les conflits énergétiques entre la croissance et les jeûnes répétés ont été étudiés à travers l’ontogénèse des capacités de plongée, afin d’estimer le coût, en terme d’histoire de vie, de restrictions alimentaires sévères au cours du dévelopement ainsi que leurs implications écologiques
The objectives of my thesis were to investigate the physiological and behavioural adaptations displayed by subantarctic fur seal pups in response to the repeated extended fasts they naturally undergo throughout their period of maternal dependence. Fasting energetics, associated endocrine changes and behavioural activity were examined in order to understand the adaptive mechanisms underlying the ontogeny of extreme fasting abilities in these animals. The adoption of an efficient strategy of energy conservation, fat storage and protein sparing (with body proteins contributing to less than 2% of total energy expenditure) in response to fasting is highlighted. Among the diverse hormones measured (thyroid hormones, cortisol, insulin, glucagon and leptin), the importance of leptin in the regulation of energetic and immune homeostasis in response to changes in nutritional state and body reserves is suggested for the first time in a free-ranging mammal (apart from primates and rodents). In addition, my results show that pup resistance to fasting develops progressively with age depending upon pronounced changes in metabolic rates and body fat stores. As a consequence, maternal foraging strategy could be constrained by ontogenetic changes in pup fasting abilities in this species. Furthermore, the trade-offs imposed by the conflicting demands of growing and surviving food deprivation upon the development of diving abilities and foraging skills were also explored in order to estimate the life history cost of extreme fasting in early life and its ecological implications

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Mison-Jooste, Valérie. "Contribution à l'étude de la biologie des populations de l'otarie à fourrure du Cap (Arctocephalus pusillus pusillus) : les soins maternels diffèrent-ils en fonction du sexe du jeune ?" Lyon 1, 1999. http://www.theses.fr/1999LYO10079.

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Le premier objectif de ce travail est l'etablissement d'une monographie sur l'otarie a fourrure du cap, explorant les caracteristiques des periodes de reproduction, de gestation et de lactation de cette espece et apportant des resultats originaux en particulier sur la croissance ftale, la duree de gestation, la croissance, la survie juvenile et le sevrage. Cette espece vit dans un environnement regule par le systeme d'upwelling du benguela et la production de ce systeme presente des variations inter-annuelles de tres forte amplitude. Ainsi, en 1994 le reseau trophique du benguela a ete atteint par une perturbation majeure de type el nino et les otaries de namibie ont subi des carences nutritionnelles ayant des consequences demographiques catastrophiques (avortements, mortalite juvenile et adulte entrainant la perte d'un tiers de la population). Ces conditions naturelles constituent des conditions analogues a des conditions experimentales permettant de tester l'hypothese selon laquelle pour une espece polygyne et sexuellement dimorphique, l'investissement maternel devrait differer en fonction du sexe du descendant. Dans le but d'etudier les strategies biodemographiques de l'otarie a fourrure du cap, les jeunes de cette espece ont ete observes sur le terrain pendant deux ans. Cette etude montre que les jeunes males presentent une masse et une croissance plus fortes que les femelles. La difference de masse a la naissance est limitee par la disponibilite des ressources ce qui indique que la gestation d'un ftus male necessite plus d'energie que celui d'un ftus femelle. Ceci suppose que cette difference provienne d'une difference de quantite d'energie transmise de la mere au jeune et non d'une difference d'utilisation de l'energie par le jeune. Des reponses au jeune similaires pour les deux sexes confortent cette hypothese. Les resultats sont replaces dans le contexte general biologique des pinnipedes.

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Ream, Rolf R. "Molecular ecology of North Pacific Otariids : genetic assessment of north fur seal and Steller sea lion distributions /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/5293.

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Gehara, Marcelo Coelho Miguel. "Filogeografia do leão-marinho-do-sul, otaria flavescens shaw 1800." Pontifícia Universidade Católica do Rio Grande do Sul, 2009. http://hdl.handle.net/10923/5319.

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We investigated the population structure of the Southern sea lion (Otaria flavescens), an otariid widely distributed along the Pacific and Atlantic coast of South America, which was heavily harvested during the two last centuries. Despite its wide distribution and interactions with fishing activities, few works evaluated the genetic differences and structuring along the species distribution. Here we used both microsatellite (10 loci) and mtDNA markers to evaluate the population structure and evolutionary history of the species. We found significant structuring between Pacific and Atlantic populations that corresponds to two reciprocally monophyletic mitochondrial lineages separated since early Pleistocene, indicating extreme female phylopatry. We also found significant genetic structure between intra-oceanic breeding sites. Microsatellites analyses also found the populations from the two oceans as significantly different with several private alleles, although very small inter-oceanic gene flow mediate by males could not be discarded. Our results show that the species did not suffer recently any significant reduction of its genetic diversity. Our findings strongly support that O. flavescens Atlantic and Pacific populations are two evolutionary significant units (ESUs) and that intra-oceanic breeding colonies should also be managed separately.
Neste estudo investigamos a estrutura populacional do leão-marinho-do-sul (Otaria flavescens), um otarideo amplamente distribuído ao longo das costas dos oceanos Atlântico e Pacífico na América do Sul, e que foi extremamente caçado durante os dois últimos séculos. Apesar de sua ampla distribuição e interações com atividades de pesca, ate o momento poucos trabalhos avaliaram as diferenças genéticas e estruturação ao longo da distribuição da espécie. No presente trabalho, utilizamos marcadores de microssatélites (10 loci) e DNA mitocondrial para avaliar a estrutura populacional e história evolutiva da espécie. Encontramos estruturação significativa entre as populações dos oceanos Pacífico e Atlântico, correspondendo a duas linhagens mitocondriais reciprocamente monofiléticas, separadas desde o início do Pleistoceno, indicando forte filopatria das fêmeas. Também encontramos estruturação genética significativa intra-oceânica entre diferentes sítios de reprodução. A análise dos microssatélites também demonstrou que as populações dos dois oceanos são significativamente diferentes, possuindo diversos alelos exclusivos, apesar de que um pequeno fluxo gênico inter-oceânico através dos machos não pode ser descartado. Nossos dados mostram que a espécie não sofreu recentemente nenhuma redução significativa na sua diversidade genética. Estes resultados indicam fortemente que as populações de O. flavescens do Pacífico e do Atlântico são duas unidades evolutivas significativas (ESUs) e que as colônias de reprodução em cada oceano devem ser manejadas separadamente.

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Gehara, Marcelo Coelho Miguel. "Filogeografia do le?o-marinho-do-sul, otaria flavescens shaw 1800." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2009. http://tede2.pucrs.br/tede2/handle/tede/176.

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Neste estudo investigamos a estrutura populacional do le?o-marinho-do-sul (Otaria flavescens), um otarideo amplamente distribu?do ao longo das costas dos oceanos Atl?ntico e Pac?fico na Am?rica do Sul, e que foi extremamente ca?ado durante os dois ?ltimos s?culos. Apesar de sua ampla distribui??o e intera??es com atividades de pesca, ate o momento poucos trabalhos avaliaram as diferen?as gen?ticas e estrutura??o ao longo da distribui??o da esp?cie. No presente trabalho, utilizamos marcadores de microssat?lites (10 loci) e DNA mitocondrial para avaliar a estrutura populacional e hist?ria evolutiva da esp?cie. Encontramos estrutura??o significativa entre as popula??es dos oceanos Pac?fico e Atl?ntico, correspondendo a duas linhagens mitocondriais reciprocamente monofil?ticas, separadas desde o in?cio do Pleistoceno, indicando forte filopatria das f?meas. Tamb?m encontramos estrutura??o gen?tica significativa intra-oce?nica entre diferentes s?tios de reprodu??o. A an?lise dos microssat?lites tamb?m demonstrou que as popula??es dos dois oceanos s?o significativamente diferentes, possuindo diversos alelos exclusivos, apesar de que um pequeno fluxo g?nico inter-oce?nico atrav?s dos machos n?o pode ser descartado. Nossos dados mostram que a esp?cie n?o sofreu recentemente nenhuma redu??o significativa na sua diversidade gen?tica. Estes resultados indicam fortemente que as popula??es de O. flavescens do Pac?fico e do Atl?ntico s?o duas unidades evolutivas significativas (ESUs) e que as col?nias de reprodu??o em cada oceano devem ser manejadas separadamente.

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Charrier, Isabelle. "La reconnaissance vocale entre la mère et son jeune chez l'otarie à fourrure de l'île d'Amsterdam, Arctocephalus tropicalis." Lyon 1, 2002. http://www.theses.fr/2002LYO10104.

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La reconnaissance mère-jeune chez l'otarie à fourrure de l'île d'Amsterdam, Arctocephalus tropicalis, se fait essentiellement par les signaux acoustiques. Face aux sévères contraintes écologiques (milieu colonial, longues séparations mère-jeune), cette espèce a développé de nombreuses adaptations dans les processus de reconnaissance vocale. Des expériences de play-back ont révélé que le bébé otarie était capable de reconnaître la voix de sa mère 2 à 5 jours après sa naissance, sa mère attendant toujours que cet apprentissage soit en place pour partir en mer. L'analyse du système de codage-décodage de l'identité individuelle a démontré que la femelle et son petit utilisent les modulations de fréquence et le spectre d'énergie du signal afin de s'identifier dans la colonie. Cette signature vocale est particulièrement efficace puisqu'elle repose sur deux paramètres (sécurité du code) dont un est particulièrement résistant aux dégradations en un milieu bruité. Les contraintes environnementales agissent à d'autres niveaux dans la communication acoustique. En effet, d'autres expériences de play-back ont démontré que les jeunes, durant l'absence de leur mère, modifiaient leur comportement vocal en fonction de leur état de satiété. Enfin, chez les femelles, les contraintes de reconnaissance du petit sont telles que la mémorisation du cri de leur petit est très puissante : elles sont capables de retenir ces différentes versions pendant toute une saison, et probablement pendant plusieurs années.

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Silva, Ana Paula da. "Organização e arquitetura microscópica do sistema tegumentar do Lobo-marinho-sul-americano (Arctocephalus australis, Zimmermann, 1783)." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/10/10132/tde-08012009-091944/.

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O lobo-marinho-sul-americano (Arctocephalus australis) membro da Ordem Carnivora, é comumente visto nos períodos de outono e inverno na costa brasileira do Rio Grande do Sul até o Rio de Janeiro, porém, sem colônias reprodutivas estabelecidas. A espécie pertence ao grupo dos pinípedes, carnívoros com membros em forma de nadadeiras que vivem em ambiente aquático e terrestre. Estudos sobre a morfologia da pele em pinípedes são raros e antigos, destes procederam muitos relatos divergentes, em virtude da colheita da pele sem referências anatômicas. O objetivo desta pesquisa foi descrever o sistema tegumentar da espécie Arctocephalus australis, utilizando animais que vieram a óbito por causas naturais de uma colônia reprodutiva do Uruguai. As áreas corporais colhidas dorso-ventralmente foram identificadas anatomicamente. Essas regiões foram examinadas por microscopia óptica, segundo critérios histológicos, histomorfométricos, histoquímicos e imuno-histoquímicos nas diferentes estruturas que constituem o sistema tegumentar. A pele do Arctocephalus australis apresentou diferenças entre as regiões de epiderme delgada e espessa. A epiderme delgada apresentou maior quantidade de pêlos do que a epiderme espessa, a qual em algumas regiões era destituída destes. Como os demais mamíferos, a pele do lobo-marinho-sul-americano apresentou glândulas sebáceas, glândulas sudoríparas apócrinas e merócrinas. As nadadeiras apresentaram o maior número de especializações entre as regiões do corpo estudadas, especialmente vinculadas à termorregulação, como o maior volume de glândulas sudoríparas e secções vasculares. Esta pesquisa apontou os aspectos morfofuncionais relacionados à biologia da espécie em ambientes distintos, e esclareceu alguns dados controversos na literatura sobre o sistema tegumentar em pinípedes.
The South American fur seal (Arctocephalus australis) members of the Order Carnivora is usually seen during the autumn and winter season in the Brazilian coast from Rio Grande do Sul to Rio de Janeiro, however, there are no reports of reproductive colonies established. The species belongs to the group of pinnipeds, carnivorous with limbs fin-shaped that inhabits both terrestrial and aquatic environments. Studies of the skin morphology are rare and ancient; these studies have arisen many divergent reports, due to sampling of the skin without anatomical references. The purpose of this research was to describe the integumentary system of the species Arctocephalus australis, using animals that came to death by natural cases from reproductive colonies from Uruguay. The body dorsal and ventral regions were identified anatomically. These regions were examined by light microscopy, according to the histological, histomophometric, histochemical and immunohistochemical criteria in the different structures constituting the integumentary system. The skin of the Arctocephalus australis showed differences between the thin and thick epidermis. The thin epidermis showed larger amount of hair follicles than the thicker epidermis, which in some regions was devoid of hair. As well as the other mammals, the South-american-fur-seal skin showed sebaceous glands, apocrine and eccrine sweat glands. The limbs showed the largest number of the specialization among the regions of the body examined, particularly related to thermoregulation, as well as the largest volume fraction of sweat glands and vascular sections. This research pointed the morphofunctional aspects related to biology of the species in different environments, and elucidated some controversial data in the investigation about the integumentary system in pinnipeds.

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Drago, Massimiliano. "Dieta y dinámica poblacional del león marino del sur ("Otaria flavescens") en Patagonia." Doctoral thesis, Universitat de Barcelona, 2010. http://hdl.handle.net/10803/832.

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El león marino del sur (Otaria flavescens), al igual que otros pinnípedos, fue intensamente perseguido por su piel y grasa. En Patagonia se estima que en la década de 1960, cuando cesó la explotación, la población se había reducido a menos del 10% de su tamaño original y permaneció sin crecer hasta la década de 1980. La reducción drástica de la población de león marino del sur no fue el único impacto humano en el ecosistema marino, ya que simultáneamente al cese de su explotación se inició la pesca industrial que podría haber afectado su recuperación, no sólo por una posible reducción en la disponibilidad de alimento, sino también por un cambio general en el funcionamiento del ecosistema.

La presente tesis doctoral tiene como objetivo general determinar hasta qué punto la recuperación del león marino del sur tras el cese de su explotación comercial se ha visto afectada por el desarrollo de la pesca industrial. Para ello se han evaluado los siguientes aspectos: 1) incidencia de la edad, el sexo y el estado reproductivo sobre la dieta, 2) incidencia de la dieta materna y de la dimensión de las colonias sobre el crecimiento y la supervivencia de las crías y 3) efecto de los cambios demográficos a largo plazo sobre la dieta y el crecimiento somático. Los resultados obtenidos demuestran: i) que los machos tienen una dieta más bentónica que las hembras y que el consumo de presas bentónicas incrementa en ambos sexos con la edad, reflejando así que el mayor tamaño asociado a una mayor edad mejora la capacidad de buceo, aunque el aprendizaje también podría jugar un papel importante tras el cese del crecimiento, ii) que las hembras incrementan el consumo de recursos bentónicos costeros después del parto, probablemente para minimizar el tiempo durante el cuál las crías permanecen desatendidas, aunque esta estrategia podría comprometer el crecimiento de las crías ya que una utilización intensiva de recursos bentónicos de menor calidad nutricional tiene un efecto negativo sobre la tasa de crecimiento de las crías, iii) que la tasa de supervivencia y de crecimiento de las crías nacidas en colonias de diferente tamaño se hallan correlacionadas negativamente, siendo la supervivencia mayor en las colonias de mayor tamaño, lo que indica la existencia de densodependencia inversa y revela la importancia del infanticidio en colonias pequeñas, iv) que la contribución relativa de recursos pelágicos de elevada calidad nutricional a la dieta de ambos sexos ha aumentado en paralelo al desarrollo de la pesca industrial, aunque al mismo tiempo se ha producido una ralentización del crecimiento somático, siendo ahora los ejemplares adultos de menor talla que hace tres décadas.

A la luz de estos resultados y teniendo en cuenta que actualmente la población de león marino del sur es aproximadamente un tercio de la población estimada antes de la explotación y que su población crece rápidamente, no parece que el desarrollo de la pesca industrial haya reducido la disponibilidad de presas para el león marino del sur en la Patagonia durante la fase inicial de recuperación demográfica, aunque en la actualidad podría estar reduciendo la capacidad de carga para la especie. Por lo tanto, el estancamiento de su población una vez cesó su explotación no puede atribuirse a una disminución de los recursos alimentarios, sino que probablemente fue debido al incremento de la mortalidad de las crías derivada del pequeño tamaño de las colonias de cría y su desestructuración social, lo que habría incrementando la tasa de infanticidio.

PALABRAS CLAVE: Ecología trófica, Isótopos estables, Densodependencia, Pinnípedos
In Patagonia the South American sea lion (Otaria flavescens) population was <10% than its original size in the 1960s, when sealing ceased and high-sea fishery development began, and stayed at stasis conditions till the 1980s. The present thesis aims to determine how the fishery development could have affected the sea lion recovery, both for a possible decrease in prey abundance and for the ecosystem upset. The following specific aims were examined: 1) age, sex and reproductive state influence on diet, 2) mother diet and colony size influence on pup growth and survival, 3) long-term demographic change influence on diet and somatic growth. Results point out: i) males have a more benthic diet than females and the benthic prey contribution increases in both sexes with the developmental stage, so indicating the increased body size with age improves the diving skill, though the age-related learning could also play a role after the growth end, ii) females increase the coastal-benthic prey consumption after parturition, likely to reduce the foraging trip duration and hence the time during which pups remain unattended on the beach, though this strategy could affect pup growth since an intensive relying on benthic prey with a lower nutritional quality than off-shore pelagic prey has a negative effect on the pup growth rate, iii) survival and growth rate of pups born in different size colonies are negatively correlated, being the survival rate higher in bigger size colonies, which indicates the existence of an inverse density dependence and reveals the importance of infanticide by subadult males in small colonies, iv) the relative contribution of off-shore pelagic prey to both sexes diet has increased in parallel with the fishery development, though a decreased somatic growth has been simultaneously recorded, being the adult individual body size smaller at present than thirty years ago. Considering results obtained and the present sea lion population on the increase, it is improbable the fishery development have decreased the prey abundance in beginning phases of Patagonian sea lion demographic recovery though it is possible it is currently decreasing the carrying capacity for the species with repercussions on body size.

KEYWORDS: Trophic ecology, Stable isotopes, Density-dependence, Pinnipeds

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Abreu, Aline Rodrigues de. "Diversidade genética e estrutura populacional do lobo-marinho sul-americano (arctocephalus australis, mammalia, carnivora, otariide) ao longo da costa atlântica da América do Sul." Pontifícia Universidade Católica do Rio Grande do Sul, 2011. http://hdl.handle.net/10923/5420.

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The South American fur Seal, Arctocephalus australis, is distributed along Southern Hemisphere coast with breeding colonies located since Peru until Uruguay. This work focuses on the Atlantic ESU and covers most of the colonies of the Atlantic coast. In recent past, several colonies underwent strong size reduction with hunting and El Niño events. Most studies have focused on investigate the Pacific ESU, little being known about the Atlantic populations. The population structure and genetic variability in this area were assayed with mitochondrial DNA control region and eleven microsatellite loci. The results found high levels of genetic diversity in the region, without evidence of recent genetic bottleneck but with evidence of a population expansion around 200-100 thousand years ago. A sign of genetic structure were found between colonies from Uruguay and Chubut when evaluated by the mtDNA. This is likely due to their strong female philopatry. However, microsatellite analysis did not revealed any existing structure, even between distant areas, supporting that most gene flow is mediated by males. For conservation purposes, these results shows that the South American fur seal Atlantic ESU is a single population and because of that, conservation measures should be aligned among the countries of its distribution.
O lobo-marinho sul-americano, Arctocephalus australis, está distribuído ao longo da costa do hemisfério sul com colônias reprodutivas localizadas desde o Peru até o Uruguai. Este trabalho foca na UES do Atlântico e cobre a maioria de suas colônias. No passado recente, várias colônias sofreram drásticas reduções populacionais com a caça e os eventos de El Niño. Muitos estudos focaram na análise da UES do Pacífico, no entanto, pouco se sabe sobre a UES do Atlântico. Neste estudo a estrutura populacional e a variabilidade genética destas populações foram avaliadas através da região controle do DNA mitocondrial e 11 loci de microssatélites. Os resultados encontraram alto nível de diversidade genética nesta região, sem sinal de gargalo genético recente, mas com sinais de uma expansão populacional iniciada entre 200. 000 e 100. 000 anos atrás. Um sinal de estruturação foi encontrado entre as colônias do Uruguai e Chubut quando avaliado a partir do DNA mitocondrial, provavelmente causado pela forte filopatria das fêmeas. No entanto, a análise de microssatélite não revelou a existência de estruturação, mesmo entre as diversas subpopulações mais distantes, sugerindo que o fluxo gênico seja mediado pelos machos. Para fins de conservação, estes resultados mostram que o lobo-marinho sul-americano da UES do Atlântico é uma única população, e por causa disso, medidas de segurança devem ser alinhadas entre os países de sua distribuição.

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PEREIRA, Eliane Machado. "Identificação da comunidade componente de helmintos, gastrointestinais hepáticos, pulmonares, cardíacos e renais de Otaria flavescens (Leão-marinho-do-sul), no litoral sul do Brasil." Universidade Federal de Pelotas, 2012. http://repositorio.ufpel.edu.br/handle/ri/2318.

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This study verified helminth parasites infection in gastrointestinal tract, lungs, heart, and kidneys of southern sea lions, Otaria flavescens, from south coast of Rio Grande do Sul State, Brazil. Twenty-nine sea-lions were found dead on the beaches, whose carcasses had mild state of decomposition, were necropsied. The organs were collected during field necropsies for laboratory analyses were 24 small and large intestines, 24 livers including parenchyma and gall bladder, 29 stomachs, 24 hearts, and 24 pairs of kidneys. The organs were maintained frozen at -20°C until their processing. A sieve with 150µm mesh was used for screening the parasites. All content retained was analyzed under stereomicroscope. The helminthes were collected, counted, fixed in AFA, stained with carmine, and clarified in beechwood creosote. The small intestines were divided into three segments that were separately analyzed to record the distribution of helminthes by preference sites. Kolmorogov-Smirnov test was used to verify the type of data distribution. Comparison of mean abundance of infection between age classes was performed through Wilcoxon test at significant level of 0.05. Correlations between infection intensity, sex, total length of the individual, and length of small and large intestines were determined using Pearson s Correlation. Action® software version 1.1 was applied for statistical analyses. Among 29 specimens of O. flavescens 23 were males, three females, and three individuals whose sex could not be determined. The average length of the animals was 2.14±0.31m (1.58 to 2.64m) including 13 sub-adults and 16 adults. A total of 996 specimens of Contracaecum ogmorhini were recorded, especially in the stomach (10.34% of prevalence), 42,145 specimens of Corynosoma australe (100% of prevalence) and 512 of Bolbosoma turbinella (50% of prevalence) were found. Two species of trematodes were found: Stephanophrora uruguayense (Prev. 4.17%) and Ascocotyle (Phagicola) longa (Prev. 33.33% ), a estimated total of 1,988.202 specimens. Cestodes were found in only one of the hosts (4.16% of prevalence) which presented four scoleces. Macroscopically, liver, gall bladder, heart, lungs, and kidneys did not contain parasites. No significant correlation was observed between infection intensity, mean abundance, sex, total length of the host, or length of intestines. Infections levels were similar between sub-adults and adults sea lions. This is the first record of Diphyllobothrium sp., Bolbosoma turbinella, Contracaecum ogmorhini, Ascocotyle (Phagicola) longa, and Stephanoprora uruguayense in O. flavescens in Brazilian waters. As regards parasite fauna of O. flavescens, our data are different from those previously reported for specimens from Pacific coast of South America.
Este estudo analisou os helmintos parasitos gastrointestinais, pulmonares, cardíacos e renais do O. flavescens no litoral sul do Rio Grande do Sul, Brasil. Foram necropsiados 29 leões-marinhos, cujas carcaças apresentavam baixo estado de decomposição. Os órgãos coletados mediante necropsia a campo para análise em laboratório foram 24 intestinos delgado e grosso, 24 fígados incluindo parênquima e vesícula biliar e 29 estômagos, 24 corações e 24 pares de rins. Os órgãos foram congelados a 20oC até o seu processamento. Para a triagem dos parasitos foi usada peneira com malha de 150 µm e todo o conteúdo retido foi analisado sob microscópio estereoscópico. Os helmintos foram fixados em AFA, corados com Carmin e clarificados com creosoto de Faia. Os intestinos delgados foram divididos em três segmentos que foram analisados separadamente para registrar a distribuição dos helmintos por sítios de preferência. Teste de Kolmorogov-Smirnov foi utilizado para verificar tipo de distribuição dos dados. A comparação da abundância média de infecção entre classes etárias foi realizada através do teste de Teste de Wilcoxon usando nível de significância de 0.05. As correlações entre intensidade de infecção, sexo, comprimento total do individuo e comprimento dos intestinos delgado e grosso foram verificadas usando a Correlação de Pearson. Para as análises estatísticas usou-se o software Action® versão 1.1. De 29 espécimes de O. flavescens 23 eram machos, três fêmeas e em três indivíduos o sexo não pode ser determinado. A média do comprimento total dos animais foi 2,14±0,31m (1,58 - 2,64m), sendo 13 subadultos e 16 adultos. Foram registrados 996 espécimes de Contracaecum ogmorhini presentes principalmente no estômago, (prevalência 10%). Registrou-se 42.145 espécimes de Corynosoma australe (Prev. 100%) e 512 de Bolbosoma turbinella (Prev. 50%). Duas espécies de trematódeos foram coletados: Stephanophrora uruguayense (Prev. 4.17% ) e Ascocotyle (Phagicola) longa (Prev. 33.33% ) totalizando 1.988.202 espécimes. Cestódeos foram encontrados em apenas um hospedeiro (Prev. 4,16%) que apresentou 4 escóleces. Macroscopicamente, fígado, vesícula biliar, coração, pulmões e rins examinados não estavam parasitados. Nenhuma correlação significativa foi observada entre a intensidade de infecção, sexo, comprimento total ou comprimento dos intestinos. Este é primeiro registro de Diphyllobothrium sp., Bolbosoma turbinella e Contracaecum ogmorhini em O. flavescens em águas brasileiras. No que se diz respeito à fauna parasitária de O. flavescens, as espécies encontradas no presente estudo não são as mesmas previamente citadas para leãomarinho-do-sul da costa pacífica da América do Sul.

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Ferrasso, Suliano. "Análise dos remanescentes de Pinípedes (Carnivora - Otariidae) em sítios arqueológicos da planície costeira do Rio Grande do Sul, Brasil." Universidade do Vale do Rio dos Sinos, 2018. http://www.repositorio.jesuita.org.br/handle/UNISINOS/7447.

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UNISINOS - Universidade do Vale do Rio dos Sinos
Os pinípedes são carnívoros marinhos que iniciam sua história evolutiva no Oligoceno médio, em torno de 65 milhões de anos. Eles ocorrem em praticamente todos os oceanos do mundo e vem interagindo com populações humanas desde a pré-história em várias regiões do globo. Para a costa brasileira já foram registradas oito espécies de pinípedes, das quais sete já foram encontradas no litoral do Rio Grande do Sul (RS). A partir da análise de remanescentes ósseos resgatados em sítios arqueológicos, sugere-se que os registros pretéritos de pinípedes na costa do Brasil estariam associados aos depósitos do Quaternário. Para o RS são poucos os trabalhos versando sobre osteologia de pinípedes, na maioria são estudos cranianos com amostras atuais sobre diagnose ou ainda dimorfismo sexual, mas muito pouco relacionado à remanescentes arqueológicos. Neste sentido é necessário um aprofundamento sobre a composição das espécies, abundância de indivíduos, ocorrência e tipo de interação destas espécies com grupos humanos pré-históricos. Para tanto o presente estudo foi realizado em cinco sítios arqueológicos do litoral Norte do Rio Grande do Sul (LNRS), localizados entre Xangri-lá (29°47'23.72"S; 50°02'1824"W) e Arroio do Sal (29°27'0.27"S; 49°49'1.74"W), os quais estavam vinculados á Tradição Sambaqui. O método de prospecção (escavação) seguiu o de cortes horizontais artificiais nivelados, aprofundando verticalmente, formando níveis artificiais sucessivos para assegurar a profundidade e origem dos remanescentes faunísticos. O volume de material prospectado nos cinco sítios variou entre 0,30 m3 e ± 15,18 m3. Neste estudo, foram selecionadas seis quadrículas com remanescentes faunísticos dos cinco sítios para análise, cada uma diferindo em tamanho e espessura estratigráfica arqueológica. Todos os remanescentes ósseos encontrados em cada quadrícula foram coletados nas trincheiras escavadas e levados para triagem e tombamento na Reserva Técnica de Arqueologia do Instituto Anchietano de Pesquisas/Universidade do Vale do Rio dos Sinos (IAP-UNISINOS). Durante a triagem em laboratório foram selecionados para este estudo exclusivamente os remanescentes de pinípedes, com base na comparação com esqueletos de espécimes de espécies atuais e da literatura. Como resultado de riqueza taxonômica sob a ótica da zooarqueologia (NISP), foram encontrados 159 remanescentes de pinípedes nos sítios do LNRS, totalizando um MNI de 17 indivíduos. O sítio RS-LN-19 de Xangri-lá apresentou o maior NISP com 130 remanescentes, unicamente da família Otariidae e com pelo menos duas espécies identificadas (Arctocephalus australis e Otaria flavescens). A análise dos remanescentes ósseos do gênero Arctocephalus revelou o predomínio de indivíduos jovens, e adultos em O. flavescens. Este resultado na composição pretérita das espécies de pinípedes encontrados nos sambaquis no litoral do RS sugere que são as mesmas que ocorrem na atualidade, além de indicar que as antigas populações humanas já interagiam com estes animais. Contudo, não se descarta a hipótese de que otariídeos antárticos e subantárticos também tenham ocorrido na região no passado, já que em alguns casos só foi possível chegar até a identificação de gênero nos remanescentes analisados. Por fim, é importante salientar que em 19,53% (n = 25) dos remanescentes ósseos encontrados, foram identificadas marcas de manipulação antrópica como corte (pequenas incisões oblíquas, transversais e subparalelas) e 5,46% (n = 7) coloração enegrecida possivelmente oriunda da queima. Desta forma sugere-se que as antigas populações humanas do LNRS poderiam utilizar os pinípedes como recurso alimentar ocasional.
Pinnipeds are marine carnivores that emerged in the mid-Oligocene, around 65 million years ago. They occur in virtually every ocean in the world and have been interacting with human populations since prehistory in various regions of the globe. For the Brazilian coast eight species of pinnipeds have already been recorded, of which seven have been found on the coast of Rio Grande do Sul. Based on the analysis of bone remnants recovered at archaeological sites, it is suggested that the past records of pinnipeds on the coast of Brazil would be associated with Quaternary deposits. For the Rio Grande do Sul state coast there are few studies on osteology of pinnipeds, mostly diagnostic or sexual dimorphism studies base on skull samples of current species but there is very little information related to archaeological remnants of pinnipeds. In this context, it is still necessary the analyses of the species composition, abundance of individuals, occurrence and type of interaction of these species with prehistoric humans in the region. The present study was carried out in five archaeological sites on the north coast of Rio Grande do Sul (NCRS), between Xangri-la (29 ° 47'23.72 "S, 50 ° 02'1824" W) and Arroio do Sal 29 ° 27'0.27 "S, 49 ° 49'1.74" W), which were linked to the Sambaqui Tradition. The method of prospecting (excavation) was used in order to obatin several artificial horizontal levels, deepening vertically, forming successive artificial levels to assure the depth and origin of the faunistic remnants. The volume of material prospected at these five sites ranged from 0.30 m3 to ± 15.18 m3. In this study, six squares with faunal remnants of the five sites were selected for analysis, each differing in size and archaeological stratigraphic thickness. All the bone remains found in each square were collected in the excavated trenches and taken to the Archaeological Technical Reserve of the Instituto Anchietano de Pesquisas / Vale do Rio dos Sinos (IAP-UNISINOS). During the laboratory screening, only the remnants of pinnipeds were selected for this study, based on the comparison with skeletons of specimens of current species and the literature. As a result of taxonomic richness from the perspective of zooarchaeology, 159 remnants of pinnipeds were found as number of idenfied specimens (NISP) in the NCRS sites, totaling a minimum number of individuals (MNI) of 17. The RS-LN-19 site of Xangri-la presented the largest NISP, with 130 remnants only for the Otariidae Family, and with at least two identified species (Arctocephalus australis and Otaria flavescens). The analysis of the bone remnants of the genus Arctocephalus revealed the predominance of young individuals, and mainly adults of O. flavescens. This result in the past composition of the pinniped species found in the sambaquis in the RS coast suggests that they are the same that occur today, besides indicating that the ancient human populations already interacted with these animals. However, it is not ruled out that Antarctic and subantarctic antarctic have also occurred in the region in the past, since in some cases it was only possible to identify until the genus in the remnants analyzed. Finally, it is important to note that in 19.53% (n = 25) of the remaining bone remnants, anthropic manipulation marks were identified as cut (small oblique, transverse and subparallel incisions) and 5.46% (n = 7) blackened spots, possibly dut to burning. In this way, it is suggested that the ancient human populations of NCRS could use pinnipeds as an occasional food resource.

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Massardier-Galatà, Lauriane. "Succès de la reproduction de prédateurs en contexte de changements climatiques et de la dynamique océanique – Application aux « central place foragers » des zones australes, approche par la modélisation individu centrée." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4050/document.

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Les changements climatiques ont un impact certain sur les écosystèmes marins. Un déplacement vers le sud des principaux systèmes de front servant de sites de nourrissage pour de nombreuses espèces de prédateurs supérieurs est susceptible de se produire dans les zones subantarctiques. Les « central place foragers », tels que les pinnipèdes, sont susceptibles de faire face à une augmentation de la distance entre leurs lieux d'alimentation et leurs colonies d'élevage. Nous avons étudié l’impact des changements climatiques sur le succès d’élevage et la dynamique de population des otaries à fourrure (Arctocephalus gazella) des Îles Kerguelen par le biais du développement du modèle individu centré, MarCPFS (Marine Central Place Foragers Simulator) qui montre que la survie du couple femelle-jeune est particulièrement sensible à la répartition des proies (abondance et structure), à la capacité de mémorisation des meilleurs sites de nourrissages trouvés par la femelle pendant la période d'élevage, à la taille des femelles et à la distance qu'il faut parcourir pour trouver la ressource. Les résultats suggèrent qu’au cours des trois prochaines décennies un déplacement vers le sud supérieur à 2km an 1 pourrait compromettre la survie et la durabilité des populations. Un couplage avec un modèle de simulation de la dynamique océanique et de la ressource (SEAPODYM) a permis des projections jusqu’à la fin de ce siècle basées sur le scénarios RCP8.5 du GIEC (2014), confirmant les tendances mises à jour précédemment. Ces travaux montrent que les perspectives de maintien des populations sont pessimistes y compris en envisageant une adaptation de la taille des individus
Climate change has certain impact on the marine ecosystems. A southward shift in productive frontal systems serving as the main foraging sites for many top predator species is likely to occur in the Subantarctic areas. Central place foragers, as seabirds and pinnipeds, are thus likely to cope with an increase in the distance between foraging locations and their land-based breeding colonies. We studied the impact of climate change on the breeding success and population dynamics of Antarctic fur seals (Arctocephalus gazella) at Kerguelen Islands by means of an individual based model we developped, MarCPFS (Marine Central Place Foragers Simulator) which showed that the survival of the female-pup pair is particularly sensitive to the distribution of preys (abundance and structure), to the memorization abilities of the best resource sites found by the female during the rearing period, to the female size and to the foraging distance which it is necessary to cover at each trip. The results suggest that during the next three decades a southward shift greater than 2 km year-1 could compromise the survival and the sustainability of the populations. A coupling with a model of simulation of the oceanic dynamics and the resource (SEAPODYM) allowed projections till the end of this century based on scenarios RCP8.5 of the IPCC (2014), confirming the trends previously obtained. Globally, these works lead us to conclude with pessimistic perspectives about the sustainability of populations even when considering an evolution through time towards individuals of greater sizes

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Abreu, Aline Rodrigues de. "Diversidade gen?tica e estrutura populacional do lobo-marinho sul-americano (arctocephalus australis, mammalia, carnivora, otariide) ao longo da costa atl?ntica da Am?rica do Sul." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2011. http://tede2.pucrs.br/tede2/handle/tede/214.

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O lobo-marinho sul-americano, Arctocephalus australis, est? distribu?do ao longo da costa do hemisf?rio sul com col?nias reprodutivas localizadas desde o Peru at? o Uruguai. Este trabalho foca na UES do Atl?ntico e cobre a maioria de suas col?nias. No passado recente, v?rias col?nias sofreram dr?sticas redu??es populacionais com a ca?a e os eventos de El Ni?o. Muitos estudos focaram na an?lise da UES do Pac?fico, no entanto, pouco se sabe sobre a UES do Atl?ntico. Neste estudo a estrutura populacional e a variabilidade gen?tica destas popula??es foram avaliadas atrav?s da regi?o controle do DNA mitocondrial e 11 loci de microssat?lites. Os resultados encontraram alto n?vel de diversidade gen?tica nesta regi?o, sem sinal de gargalo gen?tico recente, mas com sinais de uma expans?o populacional iniciada entre 200.000 e 100.000 anos atr?s. Um sinal de estrutura??o foi encontrado entre as col?nias do Uruguai e Chubut quando avaliado a partir do DNA mitocondrial, provavelmente causado pela forte filopatria das f?meas. No entanto, a an?lise de microssat?lite n?o revelou a exist?ncia de estrutura??o, mesmo entre as diversas subpopula??es mais distantes, sugerindo que o fluxo g?nico seja mediado pelos machos. Para fins de conserva??o, estes resultados mostram que o lobo-marinho sul-americano da UES do Atl?ntico ? uma ?nica popula??o, e por causa disso, medidas de seguran?a devem ser alinhadas entre os pa?ses de sua distribui??o

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Viviant, Morgane. "Optimisation du comportement d'acquisition des ressources au cours de la plongée : cas de l'otarie à fourrure antartique." Paris 6, 2011. http://www.theses.fr/2011PA066686.

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Prédire la réponse des prédateurs marins aux changements climatiques nécessite de comprendre leur écologie alimentaire. L’objectif de la thèse était d’étudier les stratégies de chasse de l’otarie à fourrure Antarctique dans le cadre des théories de l’approvisionnement optimal. Comment les otaries ajustent-elles leur comportement de plongée selon la qualité de l’environnement (abondance et accessibilité des proies en profondeur) et leurs contraintes physiologiques (limite de plongée aérobie, ADL) ? Une méthodologie basée sur les accéléromètres fut développée afin de détecter les tentatives de capture (i. E. Rencontres) de proies de ces animaux. Notre étude montre que les otaries concentrent leurs plongées à des profondeurs inférieures aux profondeurs de densité maximale de proies. Au-delà de 55-60 mètres, elles sont physiologiquement contraintes (dépassent leur ADL en moyenne) et font face à un compromis entre la disponibilité et l’accessibilité des proies. Cette contrainte affecte leurs stratégies de chasse : des plongées d’exploration ne sont utilisées qu’à faible profondeur. Contrairement aux prédictions, elles augmentent leur effort de recherche alimentaire dans les parcelles de proies de mauvaise qualité, à l’échelle des nuits. La prise en compte des contraintes physiologiques et des échelles temporelles est donc cruciale pour prédire le succès de pêche des prédateurs marins. Avec le réchauffement climatique, les scientifiques prédisent un approfondissement de la thermocline, et donc des proies. Les otaries à fourrure étant rapidement contraintes avec la profondeur, cela est susceptible d’affecter négativement leur succès alimentaire et in fine leur succès reproducteur

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Stewardson, Carolyn Louise, and carolyn stewardson@anu edu au. "Biology and conservation of the Cape (South African) fur seal Arctocephalus pusillus pusillus (Pinnipedia: Otariidae) from the Eastern Cape Coast of South Africa." The Australian National University. Faculty of Science, 2002. http://thesis.anu.edu.au./public/adt-ANU20030124.162757.

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[For the Abstract, please see the PDF files below, namely "front.pdf"] CONTENTS. Chapter 1 Introduction. Chapter 2 Gross and microscopic visceral anatomy of the male Cape fur seal with reference to organ size and growth. Chapter 3 Age determination and growth in the male Cape fur seal: part one, external body. Chapter 4 Age determination and growth in the male Cape fur seal: part two, skull. Chapter 5 Age determination and growth in the male Cape fur seal: part three, baculum. Chapter 6 Suture age as an indicator of physiological age in the male Cape fur seal. Chapter 7 Sexual dimorphism in the adult Cape fur seal: standard body length and skull morphology. Chapter 8 Reproduction in the male Cape fur seal: age at puberty and annual cycle of the testis. Chapter 9 Diet and foraging behaviour of the Cape fur seal. Chapter 10(a) The Impact of the fur seal industry on the distribution and abundance of Cape fur seals. Chapter 10(b) South African Airforce wildlife rescue: Cape fur seal pups washed from Black Rocks, Algoa Bay, during heavy seas, December 1976. Chapter 11(a) Operational interactions between Cape fur seals and fisheries: part one, trawl fishing. Chapter 11(b) Operational interactions between Cape fur seals and fisheries: part two, squid jigging and line fishing. Chapter 11(c) Operational interactions between Cape fur seals and fisheries: part three, entanglement in man-made debris. Chapter 12 Concentrations of heavy metals (Cd, Cu, Pb, Ni & Zn) and organochlorine contaminants (PCBs, DDT, DDE & DDD) in the blubber of Cape fur seals. Chapter 13 Endoparasites of the Cape fur seal. Chapter 14(a) Preliminary investigations of shark predation on Cape fur seals. Chapter 14(b) Aggressive behaviour of an adult male Cape fur seal towards a great white shark Carcharodon carcharias. Chapter 15 Conclusions and future directions.

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Stewardson, Carolyn Louise. "Biology and conservation of the Cape (South African) fur seal arctocephalus pusillus pusillus (Pinnipedia: Otariidae)from the Eastern Cape Coast of South Africa /." View thesis entry in Australian Digital Theses Program, 2001. http://thesis.anu.edu.au/public/adt-ANU20030124.162757/index.html.

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Jurczynski, Kerstin. "Tuberculosis in South American sea lions (Otaria flavescens) - diagnostic options and its epidemiologic importance for other mammals within the zoological garden." Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-99710.

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Tuberculosis is a widely spread zoonotic disease caused by acid-fast bacteria of the Mycobacterium tuberculosis complex in a variety of mammalian species. In pinnipeds, tuberculosis has been reported in different captive and wild sea lions and fur seals. The causative agent, Mycobacterium pinnipedii, is part of the M. tuberculosis complex and has shown pathogenicity in other mammalian species including human beings. Since 2000 the Heidelberg zoo has been dealing with tuberculosis in its collection of South American sea lions (Otaria flavescens). After a Malayan tapir (Tapirus indicus) was transferred to a zoological institution in France it transmitted the disease to the other tapirs that succumbed to tuberculosis. Culturing and spoligotyping confirmed the origin, the sea lions at the Heidelberg zoo. An investigation of the sea lion group housed at Heidelberg in addition to different species of mammals living in adjacent exhibits as well as a sea lion, born in Heidelberg but then living in Hamburg, revealed multiple cases of pinniped tuberculosis.

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Santestevan, Naiara Aguiar. "Isolamento e avaliação de Enterococcus spp. obtidos de amostras fecais de lobos-marinhos (Otariidae: Arctocephalus spp.) encontrados no litoral norte do Rio Grande do Sul, Brasil." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/115644.

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A distribuição das espécies de enterococos, bactérias comensais do trato gastrointestinal (TGI), é bastante estudada nos diferentes mamíferos; entretanto, em lobos-marinhos (Arctocephalus spp.) ainda não existem dados. Os objetivos do estudo foram: a) isolar Enterococcus spp. a partir de amostras fecais de lobos-marinhos encontrados no litoral norte do Rio Grande do Sul; b) determinar a prevalência das espécies; c) avaliar o perfil de suscetibilidade antimicrobiana; d) verificar a presença de genes relacionados à resistência e à virulência e; e) analisar o perfil genotípico por RAPD-PCR. No total, 160 enterococos foram isolados e identificados como E. faecalis (50,62%), E. hirae (34,37%), E. casseliflavus (11,87%), E. gallinarum (1,87%), E. mundtii (0,62%) e E. faecium (0,62%). Noventa e três isolados foram sensíveis aos dez antimicrobianos testados. As propriedades de resistência foram encontradas para eritromicina (21,25%), nitrofurantoína (15,62%), tetraciclina (6,25%), norfloxacina (3,12%) e ciprofloxacina (3,12%). Dentre os 10 isolados resistentes à tetracilina, 3 apresentaram o gene tet(M) e nenhum o tet(L). Dos 34 resistentes à eritromicina, 2 apresentaram o gene erm(B). Quanto à presença dos genes de virulência, maior incidência foi observada para os genes ace (66,87%) e gelE (50,62%), seguidos por asa (11,87%) e cylA (2,5%). A atividade de gelatinase e citolisina indicou a presença de genes silenciosos. A análise do RAPD-PCR permitiu reunir os isolados em cinco grupos. Em conclusão, diferentes espécies de enterococos compõem a microbiota do TGI de lobos-marinhos e a presença de elementos de resistência e virulência podem estar relacionados a fatores antropogênicos ou ter origem no resistoma ambiental.
The species distribution of enterococci, commensal bacteria of the gastrointestinal tract (GIT), is well studied in different mammals, however in fur seals (Arctocephalus spp.) data do not exist yet. The objectives of this study were: a) to isolate Enterococcus spp. from fecal samples of fur seals found on the North coast of Rio Grande do Sul; b) to determine the prevalence of species; c) to assess the antimicrobial susceptibility profile; d) to check the presence of resistance and virulence related genes and; e) to evaluate the genotypic profile by RAPD-PCR. A total of 160 enterococci were isolated and identified as E. faecalis (50.62%), E. hirae (34.37%), E. casseliflavus (11.87%), E. gallinarum (1.87%), E. mundtii (0.62%), and E. faecium (0.62%). Ninety-three isolates were susceptible to 10 antimicrobials tested. Resistance properties were found for erythromycin (21.25%), nitrofurantoin (15.62%), tetracycline (6.25%), norfloxacin (3.12%), and ciprofloxacin (3.12%). Among the 10 isolates resistant to tetracycline, 3 harbored the tet(M) gene and none were positive to tet(L) gene. Among the 34 erythromycin-resistant isolates, 2 harbored the erm(B) gene. Regarding the virulence genes, a higher incidence was observed for the ace (66.87%) and gelE (50.62%), followed by asa (11.87%) and cylA (2.5%). Gelatinase and cytolysin activity indicated the presence of silent genes. Analysis of RAPD-PCR allowed to assemble the isolates into five groups. In conclusion, different species of enterococci are part of the fur seals GIT microbiota and the presence of resistance and virulence elements may be related to anthropogenic factors or origin in the environmental resistome.

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Zenteno, Devaud Lisette. "Cambios en la posición trófica del lobo común sudamericano (Otaria flavescens) en respuesta a la explotación masiva de mamíferos marinos y pesca industrial." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/398133.

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Los depredadores marinos pueden cambiar su dieta a través del tiempo como consecuencia de cambios antropogénicos y naturales, por lo que un punto de referencia histórico aporta información básica y necesaria para comprender el papel ecológico que desempeñan estos individuos dentro del ecosistema que habitan. En las costas del Atlántico sudoccidental los registros zooarqueologicos e históricos revelan una importante explotación de los lobos marinos sudamericanos por parte de los colonizadores europeos y en menor grado por parte de los aborígenes cazadores recolectores, sin embargo, poco se sabe sobre la influencia de estas explotaciones sobre la dieta de esta especie. Debido a que los lobos marinos sudamericanos se caracterizan por tener un amplio nicho trófico, el determinante principal de la composición de sus dietas es la competencia intraespecifica, por lo que se espera que estos animales muestren un cambio en la posición trófica asociado a la caza indiscriminada por parte de los colonizadores europeos, y un impacto menor sobre sus poblaciones y dietas como resultado de la caza aborigen. En esta tesis doctoral se realizaron análisis de isótopos estables de carbono y nitrógeno en muestras zooarqueológicas y modernas, provenientes del centro-norte y sur de Patagonia Argentina con el objetivo de reconstruir la dieta de los lobos marinos sudamericanos desde el Holoceno tardío al presente. Los resultados revelan un marcado aumento del nivel trófico durante el siglo XX, el cual podría estar relacionado con una disminución del tamaño poblacional del lobo común sudamericano, como consecuencia de la explotación comercial, y una reducción de la competencia intraespecífica. Al contrario, tanto en Patagonia norte-centro como en Patagonia sur, las poblaciones de lobos marinos sudamericanos mostraron una estabilidad en la dieta durante varios milenios de explotación aborigen. Asimismo, no se observaron cambios significativos durante las últimas tres décadas en las razones isotópicas del hueso de machos jóvenes y adultos de lobo marino sudamericano procedentes del sur de Brasil a pesar de un dramático incremento en el desarrollo de la pesquería demersal, lo cual sugiere que la población regional se encuentra muy por debajo de la capacidad de carga. Estos resultados confirman la importancia de los análisis retrospectivos de las razones isotópicos para inferir cambios en la dieta de los depredadores oportunistas, y para identificar la transición ecológica entre ecosistemas prístinos y modificados antropogénicamente.
Marine predators may undergo remarkable dietary changes through time as a result of both anthropogenic and natural changes in the environment, and hence, a historical point of reference provides the necessary basic information to understand the ecological function of individuals in the ecosystem. In the south-west Atlantic coasts, zooarchaeological and historical records revealed a significant exploitation of South American sea lions by European colonizers and to a lesser extent by aboriginal hunter-gatherers, however, little is known about the influence of these exploitations on the diet of sea lions. Because South American sea lions have been reported as broad spectrum, the intraspecific competition plays an important role in the composition of their diets. It is therefore expected a change in the trophic position of these animals associated with the indiscriminate hunting by Western sealing, and less impact on their populations and diets as a result of aboriginal exploitation. Stable isotope ratios of carbon and nitrogen in archaeological and modern samples from northern-central and southern Patagonia, Argentina have been used in this doctoral thesis to reconstruct the dietary changes of the South American sea lion from the late Holocene to the present in the southwestern Atlantic. Results show a marked increase in trophic level during the twentieth century which might be related to the smaller population size resulting from modern sealing and the resulting reduced intraspecific competition. On the contrary, populations of South American sea lions from both in north-central Patagonia and southern Patagonia showed a stability in the diet for several millennia of aboriginal exploitation. Furthermore, no major changes were detected in the diet of male South American sea lions during the past three decades from southern Brazil despite a dramatic increase in the development of demersal fisheries, suggesting that population levels may be below of their optimal carrying capacity Results confirmed the importance of retrospective analysis of the stable isotope ratios to infer changes in the diet of opportunistic predators, and to identify the ecological transition between pristine ecosystems and anthropogenically modified.

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Rojas, Santana Valentina. "Descripción de lesiones pulmonares observadas en el estudio radiográfico simple en lobo marino (Otaria flavescens); y el diagnóstico de tuberculosis pulmonar por PCR." Tesis, Universidad de Chile, 2011. http://repositorio.uchile.cl/handle/2250/134364.

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Memoria para optar al Título Profesional de Médico Veterinario
Con el fin de pesquisar y describir las lesiones pulmonares en Lobos marinos (Otaria flavescens), se realizó un estudio radiográfico simple de tórax a 20 ejemplares cachorros y juveniles. También se realizaron lavados traqueales para la obtención de muestras que fueron analizadas para la búsqueda de bacterias del Complejo Mycobacterium tuberculosis, mediante la prueba de Reacción de Polimerasa en Cadena (PCR), con el objetivo de investigar la presencia de tuberculosis pulmonar. Para ambos estudios los animales se encontraban bajo anestesia general mediante la utilización de Isofluorano, con buena respuesta a la inducción y recuperación. Se logró estandarizar la técnica radiográfica, kVp y mAs, y se extrapoló técnica de lavados traqueales de caninos a lobos marinos. Los resultaron mostraron que 11 animales (55%) presentaban algún tipo de lesión pulmonar, en 10 individuos (50%) se observó un infiltrado del parénquima pulmonar, en 5 de ellos este infiltrado es de tipo difuso, mientras que en los 5 restantes es de tipo celular. En cuanto a la presencia de broncogramas aéreos positivos (BAP), éste estuvo presente en 9 de los individuos en estudio (45%). En lo referente la prueba de PCR, ésta arrojó resultados negativos en la totalidad de los animales, probablemente, debido a que los animales no se hayan encontrado infectados con alguna bacteria del complejo M. tuberculosis

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De, Simone Matteo. "Interazione tra squalo bianco (Carcharadon carcharias) e otaria orsina del Capo (Arctocephalus pusillus pusillus) nell'area di Seal Island a Mossel Bay, Sud Africa." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8327/.

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Gli squali bianchi sono tra i più importanti predatori dei Pinnipedi (Klimley et al., 2001; Kock, 2002). La loro principale strategia di caccia consiste nel pattugliare le acque circostanti ad una colonia di otarie e nell’attaccarle quando queste sono in movimento, mentre si allontanano o avvicinano all’isola (Klimley et al., 2001; Kock, 2002). Tuttavia, la strategia e la dinamica della predazione osservate anche in relazione al ciclo riproduttivo della preda e le tattiche comportamentali messe in atto dalla preda per ridurre la probabilità di predazione, e quindi diminuire la sua mortalità, sono ancora poco conosciute. Con questo studio, effettuato nell’area di Seal Island all’interno della baia di Mossel Bay in Sud Africa, abbiamo cercato di definire proprio questi punti ancora poco conosciuti. Per studiare la strategia e le dinamica di predazione dello squalo bianco abbiamo utilizzato il sistema di monitoraggio acustico, in modo da poter approfondire le conoscenze sui loro movimenti e quindi sulle loro abitudini. Per dare un maggiore supporto ai dati ottenuti con la telemetria acustica abbiamo effettuato anche un monitoraggio visivo attraverso l’attrazione (chumming) e l’identificazione fotografica degli squali bianchi. Per comprendere invece i loro movimenti e le tattiche comportamentali messi in atto dalle otarie orsine del capo per ridurre la probabilità di predazione nella baia di Mossel Bay, abbiamo utilizzato il monitoraggio visivo di 24 ore, effettuato almeno una volta al mese, dalla barca nell’area di Seal Island. Anche se gli squali bianchi sono sempre presenti intorno all’isola i dati ottenuti suggeriscono che la maggior presenza di squali/h si verifica da Maggio a Settembre che coincide con l’ultima fase di svezzamento dei cuccioli delle otarie del capo, cioè quando questi iniziano a foraggiare lontano dall'isola per la prima volta; durante il sunrise (alba) durante il sunset (tramonto) quando il livello di luce ambientale è bassa e soprattutto quando la presenza delle prede in acqua è maggiore. Quindi possiamo affermare che gli squali bianchi a Seal Island prendono delle decisioni che vanno ad ottimizzare la loro probabilità di catturare una preda. I risultati preliminari del nostro studio indicano anche che il numero di gruppi di otarie in partenza dall'isola di notte sono di gran lunga maggiori di quelle che partono durante il giorno, forse questo potrebbe riflettere una diminuzione del rischio di predazione; per beneficiare di una vigilanza condivisa, le otarie tendono in media a formare gruppi di 3-5 o 6-9 individui quando si allontanano dall’isola e questo probabilmente le rende meno vulnerabili e più attente dall’essere predate. Successivamente ritornano all’isola da sole o in piccoli gruppi di 2 o 3 individui. I gruppi più piccoli probabilmente riflettono la difficoltà delle singole otarie a riunirsi in gruppi coordinati all'interno della baia.

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Beauplet, Gwénaël. "Variations des performances de pêche et des performances démographiques des femelles otaries à fourrure de l'île d'Amsterdam (Arctocephalus tropicalis) : influence de la qualité individuelle et des conditions environnementales." La Rochelle, 2005. http://www.theses.fr/2005LAROS135.

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Ce travail décrit dans quelle mesure les traits d'histoire de vie sont liés aux stratégies maternelles de l'otarie à fourrure subantarctique Arctocephalus tropicalis de l'île d'Amsterdam. Pendant l'élevage du petit, les femelles ajustent leur stratégie de pêche (site, budget, proies) aux variations environnementales saisonnières. Les petits subissent des jeûnes prolongés entraînant de faibles taux de croissance. La survie pré-sevrage (69%) ne semble affectée par aucun facteur, alors que la survie post-sevrage (66%) dépend du sexe, du taux de croissance pré-sevrage, et des conditions environnementales au sevrage. La survie juvénile et adulte annuelle élevée (98%) est indépendante de l'année ou de l'environnement, et la sénescence est présente chez les femelles de plus de 13 ans. Les probabilités de survie et de reproduction futures des non-reproductrices sont inférieures à celles des reproductrices, suggérant l'existence d'un phénomène de qualité individuelle au sein de cette population
This work describes in which extent life history traits are related to the maternal strategies of subantarctic fur seal Arctocephalus tropicalis in Amsterdam Island. During pup rearing, females adjust their foraging strategies (location, activity budget, preys) with seasonal environmental variations. Pups endure extended fasting periods leading to very low growth rates. Preweaning survival (69%) seems to be not affected by any studied factors, while postweaning survival (66%) is dependent of pup sex, preweaning growth rate, and environmental conditions at weaning. High juvenile and adult annual survival rate (98%) is independent of the year or environment, and a senescence effect was shown in females older than 13 years old. Future survival and reproduction probabilities in nonbreeders are lower than in breeders, suggesting a phenomenon of individual quality in this population

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Buckles, Elizabeth Louise. "Investigations into the association between Otarine Herpesvirus 1 and endemic cancer in California sea lions (Zalophus californianus) : age class, tissue distribution and in vitro cultivation of the virus /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.

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Roux, Jean-Paul. "Sociobiologie de l'Otarie : Arctocephalus tropicalis." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37600894r.

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Georges, Jean-Yves. "Stratégies maternelles de l'otarie à fourrure de l'île Amsterdam, Arctocephalus tropicalis : relations avec les conditions environnementales." La Rochelle, 2000. http://www.theses.fr/2000LAROS041.

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Les stratégies maternelles de l'otarie à fourrure, de l'ile Amsterdam, Arctocephalus tropicalis, ont été étudiées en relation avec les conditions environnementales au cours de trois années consécutives (1995, 1996, 1997). Au cours d'une saison de reproduction, les otaries donnent naissance à un jeune unique puis alternent des voyages en mer où elles s'alimentent (acquisition des ressources) et des visites à terre où elles allaitent leur petit (allocation des ressources). Les stratégies d'acquisition des ressources ont été abordées par l'étude de l'écologie en mer des femelles allaitantes, grâce à l'utilisation combinée de balises Argos, d'enregistreurs de plongée et de direction, et du suivi individuel du changement de masse corporelle des mères et de leur jeune. Les otaries d'Amsterdam présentent une écologie en mer singulière au sein des otaries à fourrure. Elles effectuent des voyages alimentaires particulièrement longs au cours desquels elles rejoignent la bordure nord du front subtropical, située en milieu océanique à environ 400-500 km de l'ile Amsterdam. Elles présentent un comportement de plongée nocturne, et semblent ajuster leur comportement de pêche en fonction des migrations verticales nycthémérales de leurs proies principales, les myctophides. Elles modifient leur comportement de prospection du milieu marin en fonction des variations saisonnières et annuelles des conditions océanographiques, en particulier la profondeur de la couche de mélange, la distance au site d'alimentation, et le gradient de température de surface du front subtropical. L’éloignement du site d'alimentation indique que les otaries d'Amsterdam sont habituellement confrontées à des conditions trophiques particulièrement mauvaises tout au long de la saison de reproduction. Les stratégies d'allocation des ressources ont été abordées par l'étude de l'investissement prénatal et par la description de la croissance postnatale du jeune, grâce à un suivi individuel de la masse à la naissance et de la croissance des jeunes. Cette étude propose que les couts énergétiques associés à la production d'un fœtus male sont en général supérieurs à ceux associés à la production d'un fœtus femelle. Toutefois, la quantité d'énergie allouée à la gestation semble également dépendre de la condition corporelle maternelle et des conditions trophiques rencontrées au cours de la gestation. Au cours de la lactation, les soins maternels postnataux ne diffèrent pas en fonction du sexe du jeune. Les otaries d'Amsterdam semblent adopter un schéma d'approvisionnement permettant d'optimiser le taux d'acquisition des ressources de leur jeune au cours d'un cycle d'approvisionnement et sur l'ensemble de la lactation. Les mères maintiennent la croissance de leur jeune pendant les 7 premiers mois en ajustant le schéma d'approvisionnement et la qualité du lait fourni au jeune. Plus tard dans la saison, les mères ne parviennent pas à maintenir la croissance de leur jeune, suggérant que la disponibilité des ressources diminue fortement en hiver. Des différences inter-annuelles de la masse à la naissance, du taux de croissance, et de la masse au sevrage suggèrent que les otaries d'Amsterdam étaient confrontées à des conditions environnementales variables au cours de cette étude. Les résultats obtenus au cours de cette étude sont discutés au sein des pinnipèdes, et soutiennent les récentes hypothèses selon lesquelles les stratégies maternelles des pinnipèdes seraient principalement influencées par la distance au site d'alimentation et la disponibilité des ressources marines (Ono & Boness 1996, Trillmich 1996). Ce travail mené sur 3 années montre que l'étude de prédateurs marins supérieurs peut fournir des indices naturels des conditions environnementales et de la disponibilité des ressources marines. Dans le cas des otaries d'Amsterdam, ces indices concernent une région océanique difficilement accessible, et un systeme frontal très peu étudié, le front subtropical. Ces informations peuvent se révéler d'autant plus précieuses que le front subtropical semble contribuer de manière significative à la production biologique de l'océan austral.

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Worms, Otari [Verfasser], and Sven [Akademischer Betreuer] Ackermann. "Unterschiede und Gemeinsamkeiten der intra- und postpartalen Behandlung des Gestationsdiabetes in verschiedenen ethnischen Bevölkerungsgruppen des Rhein-Main-Gebietes / Otari Worms. Gutachter: Sven Ackermann." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2014. http://d-nb.info/1075743214/34.

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Jurczynski, Kerstin [Verfasser], Klaus [Akademischer Betreuer] Eulenberger, Klaus [Gutachter] Eulenberger, and Andreas [Gutachter] Beineke. "Tuberculosis in South American sea lions (Otaria flavescens) - diagnostic options and its epidemiologic importance for other mammals within the zoological garden / Kerstin Jurczynski ; Gutachter: Klaus Eulenberger, Andreas Beineke ; Betreuer: Klaus Eulenberger." Leipzig : Universitätsbibliothek Leipzig, 2012. http://d-nb.info/1238240852/34.

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Barraza, Luna Erik Rodolfo. "Estimación de riesgo de desastres en proyectos de inversión pública para servicios de saneamiento básico de los pueblos localizados en la cuenca del río Otari, distrito de Pichari – provincia La Convención – región Cusco." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2016. https://hdl.handle.net/20.500.12672/5793.

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Proporciona una metodología a seguir para determinar el nivel de riesgo de desastres para la cuenca del río Otari en el distrito de Pichari, provincia La Convención de la región Cusco. Emplea el método matemático desarrollado por Thomas L. Saaty (1980), en ella se utiliza una serie de matrices que permiten determinar los niveles, establecidos por INDECI, de peligro y vulnerabilidad para luego hallar el riesgo. La cuenca del río Otari necesita contar con estudios de estimación de riesgo de desastres que mitiguen aquellos que se notan en los pueblos, así como el establecimiento descontrolado de hogares en zonas de peligros generados por los fenómenos de geodinámica interna y externa. Con el empleo del método matemático se determinó que la cuenca del río Otari presenta un peligro de nivel medio y una vulnerabilidad de nivel alto, dando por resultado un riesgo de nivel alto, de tal forma se hace necesario y obligatorio las medidas preventivas. Este estudio permite además, elaborar mapas temáticos que faciliten la visualización de los riesgos en la zona de interés, para ello se usarían los diversos valores hallados en los parámetros y descriptores de las matrices.
Tesis

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McKenzie, Jane, and janemckenzie@malpage com. "Population demographics of New Zealand fur seals (Arctocephalus forsteri)." La Trobe University. Zoology Department, School of Life Sciences, 2006. http://www.lib.latrobe.edu.au./thesis/public/adt-LTU20080509.121141.

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Assessment of trophic interactions between increasing populations of New Zealand fur seals (Arctocephalus forsteri) and fisheries in southern Australia is limited due to a lack of species specific demographic data and an understanding of the factors influencing population growth. To establish species specific demographic parameters a cross-sectional sample of New Zealand fur seal females (330) and males (100) were caught and individually-marked on Kangaroo Island, South Australia between 2000 and 2003. The seals were aged through examination of a postcanine tooth, which was removed from each animal to investigate age-specific life-history parameters. Annual formation of cementum layers was confirmed and accuracy in age estimation was determined by examination of teeth removed from individuals of known-age. Indirect methods of assessing reproductive maturity based on mammary teat characteristics indicated that females first gave birth between 4-8 years of age, with an average age at reproductive maturity of 5 years. Among reproductively mature females, age-specific reproductive rates increased rapidly between 4-7 years of age, reaching maximum rates of 70-81% between 8-13 years, and gradually decreased in older females. No females older than 22 years were recorded to pup. Age of first territory tenure in males ranged from 8-10 years. The oldest female and male were 25 and 19 years old, respectively. Post-weaning growth in females was monophasic, characterised by high growth rates in length and mass during the juvenile growth stage, followed by a gradual decline in growth rates after reproductive maturity. In contrast, growth in males was biphasic and displayed a secondary growth spurt in both length and mass, which coincided with sexual and social maturation, followed by a rapid decline in growth rates. Age-specific survival rates were high (0.823-0.953) among prime-age females (8-13 yrs of age) and declined in older females. Relative change in annual pup production was strongly correlated with reproductive rates of prime-age females and adult female survival between breeding seasons.

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Lowther, Andrew Damon. "Alternate foraging strategies and population structure of adult female Australian sea lions." Thesis, 2012. http://hdl.handle.net/2440/95880.

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Otariid seals pose several challenges in collecting behavioural data due because of the geographical decoupling of breeding habitat (terrestrial) and foraging grounds (aquatic). Additionally, life history traits such as breeding chronology and moult state constrain the temporal window over which data can be collected. Expensive telemetry devices coupled with logistical difficulties and the biology of animals often limits the ability to answer questions concerning the role of seasonal or life-history differences in foraging ecology. However, quantifying individual behavioural specialisations such as foraging behaviour that may impede gene flow is an essential prerequisite to understanding population structure. Several unusual life history traits of the IUCN Red Listed (threatened) Australian sea lion Neophoca cinerea are interesting from an ecological, evolutionary and conservation standpoint. Australian sea lions are endemic to the southern and western coastline of Australia, distributed over approximately 70 breeding colonies with 86% of all breeding occurring in South Australia. Most notably, a unique 17.5month breeding chronology and asynchronous breeding between spatially-close colonies has been proposed to be an adaptive response to a low-quality foraging environment that has little or no seasonality. Contrary to this, recent studies suggest at least the South Australian range of the species is a region replete with mesoscale areas of seasonally rich productivity, further supported by the presence of large numbers of other top marine predators and the largest volume fishery in Australia. In the face of this contradiction, the ecological determinants of population structure clearly have yet to be identified. To address these key knowledge gaps, this study explored the population structure and foraging behaviour of adult female Australian sea lions at seventeen of the largest breeding colonies across the South Australian range. A novel screening technique which employed δ¹³C and δ¹⁵N present in the whiskers of wholly milk-dependent pups was developed and validated as a proxy for maternal values. Mother-to-pup fractionation was quantified, with a δ¹⁵N enrichment of +1.92‰ (blood) and +1.27‰ (vibrissae). Subsequent large-scale sampling of >50% of all pups born on each colony suggested a degree of ecological partitioning over a spatial scale never previously described for otariids. Isotope ratios of serially-subsampled vibrissae from 20 adult female Australian sea lions across seven breeding colonies revealed individual long-term temporal consistency in both foraging site (offshore vs inshore) and prey selection. Furthermore, dive and movement parameters did not differ between alternate foraging ecotypes, suggesting that the alternate foraging strategies of adult female Australian sea lions were temporally persistent and unrelated to phenotypic variation. Finally, individual foraging specialisation and matrilineal population structure were integrated by obtaining isotope and mitochondrial DNA (mtDNA) samples from over 50% of all pups born at each of 17 breeding colonies in order to characterise foraging ecotype composition and matrilineal population structure. Alternate foraging ecotypes were present at almost every colony with no evidence to support particular mitochondrial lineages were restricted to specific foraging ecotypes. Spatial analysis of molecular data identified three putatitive clusters of colonies that share multiple haplotypes being interspersed with 9 singleton breeding sites, with genetic structure becoming more apparent at colonies closer to deep water. Colonies with little or no similarity in mtDNA haplotype composition were more likely to breed asynchronously irrespective of the geographic distance between them. Contrary to expectations, the propensity for individual animals to forage offshore was unrelated to the proximity of breeding colonies to deep water. This study adds considerable knowledge to our current understanding of Australian sea lion foraging behaviour and highlights the inappropriateness of making broad-scale inferences about foraging ecology or population structure in this species. Individual foraging specialisation may act as an ecological barrier to migration, with individuals only able to disperse to colonies within range of preferred fine-scale foraging habitat where they have appropriate hunting skills.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2012

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Müller, Gabriele [Verfasser]. "The foraging ecology of South American sea lions (Otaria flavescens) on the Patagonian Shelf / vorgelegt von Gabriele Müller." 2004. http://d-nb.info/973616075/34.

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Stewardson, Carolyn Louise. "Biology and conservation of the Cape (South African) fur seal Arctocephalus pusillus pusillus (Pinnipedia: Otariidae) from the Eastern Cape Coast of South Africa." Phd thesis, 2001. http://hdl.handle.net/1885/48199.

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Chapter 1 Introduction. Chapter 2 Gross and microscopic visceral anatomy of the male Cape fur seal with reference to organ size and growth. Chapter 3 Age determination and growth in the male Cape fur seal: part one, external body. Chapter 4 Age determination and growth in the male Cape fur seal: part two, skull. Chapter 5 Age determination and growth in the male Cape fur seal: part three, baculum. Chapter 6 Suture age as an indicator of physiological age in the male Cape fur seal. Chapter 7 Sexual dimorphism in the adult Cape fur seal: standard body length and skull morphology. Chapter 8 Reproduction in the male Cape fur seal: age at puberty and annual cycle of the testis. Chapter 9 Diet and foraging behaviour of the Cape fur seal. Chapter 10(a) The Impact of the fur seal industry on the distribution and abundance of Cape fur seals. Chapter 10(b) South African Airforce wildlife rescue: Cape fur seal pups washed from Black Rocks, Algoa Bay, during heavy seas, December 1976. Chapter 11(a) Operational interactions between Cape fur seals and fisheries: part one, trawl fishing. Chapter 11(b) Operational interactions between Cape fur seals and fisheries: part two, squid jigging and line fishing. Chapter 11(c) Operational interactions between Cape fur seals and fisheries: part three, entanglement in man-made debris. Chapter 12 Concentrations of heavy metals (Cd, Cu, Pb, Ni & Zn) and organochlorine contaminants (PCBs, DDT, DDE & DDD) in the blubber of Cape fur seals. Chapter 13 Endoparasites of the Cape fur seal. Chapter 14(a) Preliminary investigations of shark predation on Cape fur seals. Chapter 14(b) Aggressive behaviour of an adult male Cape fur seal towards a great white shark Carcharodon carcharias. Chapter 15 Conclusions and future directions.

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Biagiotti, Barchiesi María Candelaria. "Características de las interacciones entre machos de lobo marino de un pelo (Otaria flavescens ) en el apostadero no reproductivo del Puerto de Mar del Plata." Bachelor's thesis, 2021. http://hdl.handle.net/11086/22104.

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111 h. ils.; tabls.; figuras. Contiene Referencia Bibliográfica
La presente Tesis de Grado busca estudiar las características de las interacciones y peleas lúdicas entre machos de O. flavescens en el apostadero no reproductivo del Puerto de Mar del Plata, y la posible influencia de variables ambientales y temporales. En la colonia no reproductiva de Mar del Plata, la actividad social tiene una gran importancia en la adquisición de habilidades comportamentales para la participación en las colonias reproductivas, por lo que las interacciones más frecuentes son aquellas en las que se involucran ejemplares pre-reproductivos. En contextos no reproductivos y unisexuales, la duración y diversidad de los comportamientos son distintas respecto a contextos reproductivos, con variaciones entre ejemplares pre-reproductivos y reproductivos. El total de interacciones observado, está influenciado por las siguientes variables ambientales: fase lunar, marea, hora, período del año, y el número de animales en playa. OBJETIVO GENERAL Caracterizar la diversidad e inversión de tiempo en las interacciones entre machos de O. flavescens en la colonia no reproductiva del Puerto de Mar del Plata, e indagar en la influencia de variables ambientales y temporales...
Fil: Biagiotti Barchiesi, María Candelaria. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales; Argentina.
Fil: Biagiotti Barchiesi, María Candelaria. Universidad Nacional de Mar del Plata; Argentina.
Fil: Biagiotti Barchiesi, María Candelaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Marinas y Costeras; Argentina.

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Soto, Karim H. "The effects of prey abundance on the diet, maternal attendance and pup mortality of the South American sea lion (Otaria flavescens) in Peru." Thesis, 2004. http://hdl.handle.net/2429/16219.

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The Peruvian upwelling system is one of the most unpredictable but productive marine ecosystems in the world that is regularly affected by El Nino and La Nina events. As a consequence, South American sea lions (Otaria flavescens) inhabiting the Peruvian coast face stochastic fluctuations in the abundance and distribution of their prey. The goal of my study was to determine the effects of marine environmental changes on the reproductive success of South American sea lions in Peru on the Ballestas Islands during the 1997-2002 breeding seasons. I also wanted to assess whether changes in diet and maternal behaviour during this time were proxies of major changes in the abundance of marine resources. South American sea lions consumed primarily anchovy and squat lobster during the 1999- 2001 La Nina, but consumed a greater diversity of prey when abundance was low during the 1997-1998 El Nino. Lactating females also modified the length of time they spent at sea and onshore in response to changes in the abundance of prey. Low abundances and quality of prey during El Nino caused females to continue foraging for longer periods. This resulted in greater times between nursing episodes, and ultimately led to the starvation of pups. In contrast, during the 1999-2001 La Nina, females spent shorter times at sea and longer times onshore as prey became more abundant. Pup production and mortality were also directly related to the abundance of prey. Pup mortality reached 100% during El Nino and remained high during the favourable conditions of La Nina due to the short-term effects that El Nino had on population dynamics and subsequent maternal behaviour. Abortions were also higher during El Nino compared to other years, while numbers of pups bom were significantly reduced during and after El Nino due to the death of a high proportion of the adult population. My study suggests that South American sea lions in Peru are highly vulnerable to extreme changes in prey abundance. It also demonstrates that sea lion reproductive parameters, maternal attendance, and diet are strongly related to marine environmental conditions and annual variations in prey abundance. As a result, South American sea lions appear to be good indicators of stochastic changes in the distribution and abundance of marine resources in the Peruvian upwelling ecosystem.
Science, Faculty of
Zoology, Department of
Graduate

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Taylor, Christopher Russell. "Cultural perceptions of the Wellington landscape 1870 to 1900 : an anthropological interpretation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Social Anthropology at Massey University, Palmerston North, New Zealand." 2008. http://hdl.handle.net/10179/781.

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This thesis examines how cultural perceptions of Wellington’s environment changed from the 1870s to the early 1900s. The historical material shows how clearing the New Zealand landscape of its forest cover in the early settler years reflected a particular cultural perception of the New Zealand bush. By 1900, this cultural perception had changed indicating that not only was the New Zealand landscape different, but New Zealand society had changed. These changes can be seen in the geographic historical accounts of clearing New Zealand’s bush and the parliamentary debates of the 1875 Forest Act, 1885 State Forest Act and the 1903 Scenery Protection Act. The anthropological theories of dwelling, taskscape, phenomenology of landscape and the hybridity of nature are used as a contemporary synthesis of ideas to examine cultural perceptions of the Wellington bush. An anthropological approach is also used to bring together diverse historical material in a way that allows these ideas to be applied. Cultural perceptions of the Wellington landscape can be understood in the way the bush was cleared for pasture, how the landscape was depicted in paintings and photography and in the case study of the establishment of Otari-Wilton’s Bush. The thesis argues that cultural perceptions can be appreciated historically by understanding how people lived within the Wellington landscape, and how this was reflected in attitudes towards the New Zealand bush. Cultural perceptions of New Zealand’s bush were a combination of existing cultural attitudes, the practicalities of living within the New Zealand environment and a direct perception of the bush itself. It is the shifting influence of all three of these aspects that determines overall cultural perceptions of the bush in any particular period in New Zealand’s history. The establishment of Otari-Wilton’s Bush shows how the cultural perception of Wellington’s bush had changed from seeing it as an obstruction covering potential farmland to having a defined place and purpose within the Wellington landscape.

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Dissertations / Theses on the topic 'Otariid'

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