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Journal articles on the topic "Otarid"
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Boessenecker, Robert W., and Morgan Churchill. "The oldest known fur seal." Biology Letters 11, no. 2 (February 2015): 20140835. http://dx.doi.org/10.1098/rsbl.2014.0835.
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The poorly known fossil record of fur seals and sea lions (Otariidae) does not reflect their current diversity and widespread abundance. This limited fossil record contrasts with the more complete fossil records of other pinnipeds such as walruses (Odobenidae). The oldest known otariids appear 5–6 Ma after the earliest odobenids, and the remarkably derived craniodental morphology of otariids offers few clues to their early evolutionary history and phylogenetic affinities among pinnipeds. We report a new otariid, Eotaria crypta , from the lower middle Miocene ‘Topanga’ Formation (15–17.1 Ma) of southern California, represented by a partial mandible with well-preserved dentition. Eotaria crypta is geochronologically intermediate between ‘enaliarctine’ stem pinnipedimorphs (16.6–27 Ma) and previously described otariid fossils (7.3–12.5 Ma), as well as morphologically intermediate by retaining an M 2 and a reduced M 1 metaconid cusp and lacking P 2–4 metaconid cusps. Eotaria crypta eliminates the otariid ghost lineage and confirms that otariids evolved from an ‘enaliarctine’-like ancestor.
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Kovacs, Kit M., and D. M. Lavigne. "Maternal investment in otariid seals and walruses." Canadian Journal of Zoology 70, no. 10 (October 1, 1992): 1953–64. http://dx.doi.org/10.1139/z92-265.
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We examined neonatal size, growth rate during lactation, weaning mass, adult body mass, and the degree of polygyny among fur seals and sea lions (Otariidae) and walruses (Odobenidae). Observed patterns of maternal and sexual investment were compared with those reported for true seals (Phocidae) and for other mammals. There was a strong positive interspecific allometric relationship between mass at birth and maternal mass for otariid species (p < 0.001). The slope of this relationship was significantly different from that for phocid species (p < 0.001). All pinniped data were above the regression line for terrestrial mammals. Lactation was longer and growth rates were slower for otariid and odobenid species than for phocid species. The cyclic foraging pattern of lactating otariids allows for more flexibility in the duration of lactation than is possible in phocids. Such flexibility may serve as a buffer when food is scarce. The longer lactation period of otariids and walruses also permits offspring to develop swimming and foraging skills while still depending on their mothers for energy. The relationship of mass at weaning to maternal mass suggests a greater investment in each neonate in otariids and walruses than in phocids. The large body size and advanced state of development at weaning may be an adaptive response to predation pressure on otariids. Adult male otariids and walruses are larger than females and, in both families, the average birth mass, mass at weaning, and growth rate of male pups are greater than those of females. The ratio of body masses of male pups to female pups at birth and at weaning was not correlated with the degree of adult sexual dimorphism within species, despite a positive correlation between the ratio of body masses of adult males to adult females and the degree of polygyny across otariid species.
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Hernández-Orts, J. S., F. E. Montero, A. Juan- García, N. A. García, E. A. Crespo, J. A. Raga, and F. J. Aznar. "Intestinal helminth fauna of the South American sea lion Otaria flavescens and fur seal Arctocephalus australis from northern Patagonia, Argentina." Journal of Helminthology 87, no. 3 (September 12, 2012): 336–47. http://dx.doi.org/10.1017/s0022149x12000454.
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AbstractWe report on the intestinal helminth fauna of 56 South American sea lions, Otaria flavescens, and 5 South American fur seals, Arctocephalus australis, from northern Patagonia, Argentina. A total of 97,325 helminth specimens were collected from sea lions. Gravid individuals were represented by 6 species of parasites: 1 digenean (Ascocotyle (Ascocotyle) patagoniensis), 1 cestode (Diphyllobothrium spp.), 3 nematodes (Uncinaria hamiltoni, Contracaecum ogmorhini s.s., Pseudoterranova cattani) and 1 acanthocephalan (Corynosoma australe). In addition, third-stage larvae of 2 nematodes (Contracaecum sp. and Anisakis sp. type I) and 3 juvenile acanthocephalans (Andracantha sp., Profilicollis chasmagnathi and Corynosoma cetaceum) were also collected. Andracantha sp., C. ogmorhini s.s. and P.chasmagnathi represent new host records. A total of 1516 helminth specimens were collected from fur seals. Gravid individuals were represented by three species of parasites, namely, Diphyllobothrium spp., C. ogmorhini s.s. and C. australe. In addition, larvae of Contracaecum sp. and P. cattani, juveniles of C. cetaceum and immature cestodes (Tetrabothriidae gen. sp.) were also collected. Corynosoma australe was the most prevalent and abundant parasite in both hosts, accounting for >90% of all specimens. Sea lions and furs seals from northern Patagonia harbour the intestinal helminth communities that could be predicted for otariids, i.e. the combination of species of the genera Corynosoma, Diphyllobothrium, Pseudoterranova, Contracaecum and, in pups, Uncinaria. Additionally, both species of otariid are apparently unsuitable hosts (i.e. non-hosts) for as many as five parasite taxa. The inclusion or exclusion of these species affects estimation of species richness at both component community (11 versus 6 species in sea lions; 7 versus 3 species in fur seals) and infracommunity (mean: 3.1 versus 2.6 in sea lions; 2.2 versus 1.7 species) levels. Information about the reproductive status of helminth species is often lacking in parasitological surveys on otariids and other marine vertebrates, but it is of significance to improve precision in parascript studies or ecological meta-analyses.
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Wierucka, Kaja, Benjamin J. Pitcher, Robert Harcourt, and Isabelle Charrier. "The role of visual cues in mother–pup reunions in a colonially breeding mammal." Biology Letters 13, no. 11 (November 2017): 20170444. http://dx.doi.org/10.1098/rsbl.2017.0444.
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Parental care is an important factor influencing offspring survival and adult reproductive success in many vertebrates. Parent–offspring recognition ensures care is only directed to filial young, avoiding the costs of misallocated resource transfer. It is essential in colonial mammal species, such as otariids (fur seals and sea lions), in which repeated mother–offspring separations increase the risk of misdirecting maternal effort. Identification of otariid pups by mothers is known to be multi-modal, yet the role of visual cues in this process remains uncertain. We used three-dimensional visual models to investigate the importance of visual cues in maternal recognition of pups in Australian sea lions ( Neophoca cinerea ). We showed that the colour pattern of pup pelage in the absence of any other sensory cues served to attract the attention of females and prompt investigation. Furthermore, females were capable of accurately distinguishing between models imitating the age-class of their own pup and those resembling older or younger age-classes. Our results suggest that visual cues facilitate age-class discrimination of pups by females and so are likely to play an important role in mother–pup reunions and recognition in otariid species.
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Churchill, Morgan, and Robert W. Boessenecker. "Taxonomy and biogeography of the Pleistocene New Zealand sea lionNeophoca palatina(Carnivora: Otariidae)." Journal of Paleontology 90, no. 2 (March 2016): 375–88. http://dx.doi.org/10.1017/jpa.2016.15.
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AbstractThe Otariidae (fur seals and sea lions) are an important and highly visible component of Southern Hemisphere marine mammal faunas. However, fossil material of Southern Hemisphere otariids is comparatively rare and often fragmentary. One exception is the Pleistocene sea lionNeophoca palatinaKing, 1983a, which is known from a nearly complete skull from the North Island of New Zealand. However, the phylogenetic affinities of this taxon are poorly known, and comparisons with other taxa have been limited. We provide an extensive redescription ofNeophoca palatinaand diagnose this taxon using a morphometric approach. Twenty measurements of the skull were collected forN. palatina, as well as for all extant Australasian otariids and several fossilNeophoca cinereaPerón, 1816. Using principal component analysis, we were able to segregate taxa by genus, andN. palatinawas found to cluster withNeophocaaccording to overall size of the skull as well as increased width of the intertemporal constriction and interorbital region.N. palatinacan be distinguished from all other Australasian otariids by its unusually broad basisphenoid. Discriminant function analysis supported referral ofNeophoca palatinatoNeophocawith very high posterior probability. These results confirm the treatment ofNeophoca palatinaas a distinct species ofNeophocaand highlight the former broad distribution and greater tolerance for colder temperatures of this genus. These results also suggest that New Zealand may have played a pivotal role in the diversification of Southern Hemisphere otariid seals.
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Berta, Annalisa, Morgan Churchill, and Robert W. Boessenecker. "The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses." Annual Review of Earth and Planetary Sciences 46, no. 1 (May 30, 2018): 203–28. http://dx.doi.org/10.1146/annurev-earth-082517-010009.
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The oldest definitive pinniped fossils date from approximately 30.6–23 million years ago (Ma) in the North Pacific. Pinniped monophyly is consistently supported; the group shares a common ancestry with arctoid carnivorans, either ursids or musteloids. Crown pinnipeds comprise the Otariidae (fur seals and sea lions), Odobenidae (walruses), and Phocidae (seals), with paraphyletic “enaliarctines” falling outside the crown group. The position of extinct Desmatophocidae is debated; they are considered to be closely related to both otariids and odobenids or, alternatively, to phocids. Both otariids and odobenids are known from the North Pacific, diverging approximately 19 Ma, with phocids originating in the North Atlantic or Paratethys region 19–14 Ma. Our understanding of pinniped paleobiology has been enriched by studies that incorporate anatomical and behavioral data into a phylogenetic framework. There is now evidence for sexual dimorphism in the earliest pinnipeds, heralding polygynous breeding systems, followed by increased body sizes, diving capabilities, and diverse feeding strategies in later-diverging phocid and otarioid lineages.
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Fiorito, C., J. Marfil, E. Falzoni, M. Martínez Vivot, M. Zumárraga, D. Lombardo, and S. Barandiaran. "Tuberculosis in wild South American sea lions Otaria flavescens stranded in Chubut, Argentina." Diseases of Aquatic Organisms 142 (November 19, 2020): 33–40. http://dx.doi.org/10.3354/dao03520.
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Pinniped tuberculosis, commonly caused by Mycobacterium pinnipedii, is a zoonotic disease reported in free-living and captive otariid species of the southern hemisphere. Currently, data concerning pinniped tuberculosis in South America are scarce, reinforcing the need for further studies of the disease in free-ranging pinnipeds. In this study, we investigated the presence of tuberculosis in South American sea lions Otaria flavescens (SASLs) stranded along the Chubut coastline (Argentina). Necropsies were performed in 9 SASLs, and tissue samples were collected for histopathology, bacteriology, and molecular diagnosis. Four SASLs showed enlarged tracheobronchial lymph nodes (TBLNs) with multifocal to coalescing granulomas. In these animals, a direct IS6110-PCR amplification confirmed the presence of a Mycobacterium tuberculosis complex member in TBLNs (n = 4) and lungs (n = 2), but the agent could not be further identified. In one SASL, Mycobacterium murale was isolated from lungs without lesions. This study confirms the presence of tuberculosis in SASLs from Chubut, where tourist activities promote close interaction with the animals, generating a potential risk to human health. Further research is currently focusing on addressing the prevalence of tuberculosis in wild SASLs, to assess the risk for public health and develop management strategies to avoid human infection.
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Velez-Juarbe, Jorge. "Eotaria citrica, sp. nov., a new stem otariid from the “Topanga” formation of Southern California." PeerJ 5 (February 23, 2017): e3022. http://dx.doi.org/10.7717/peerj.3022.
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A new taxon of stem otariid,Eotaria citricasp. nov., is described from the upper Burdigalian to lower Langhian “Topanga” formation of Orange County, California. The new species is described from mandibular and dental remains that show a unique combination of plesiomorphic and derived characters. Specifically, it is characterized by having trenchant and prominent paraconid cusps in p3–m1, lingual cingula of p2–4 with faint crenulations, premolars and molars with vestigial metaconid, bilobed root of m2 and a genial tuberosity located under p3. Furthermore, additional material of the contemporaneousEotaria cryptais described, providing new information on the morphology of this taxon. Both species ofEotariarepresent the earliest stem otariids, reinforcing the hypothesis that the group originated in the north Eastern Pacific Region. At present, the “Topanga” Fm. pinniped fauna includesEotaria citrica,Eotaria crypta, the desmatophocidAllodesmussp., the odobenidsNeotheriumsp.,Pelagiarctossp. and includes the oldest records of crown pinnipeds in California. Overall this pinniped fauna is similar to the nearly contemporaneous Sharktooth Hill bonebed. However, unambiguous records ofEotariaare still missing from Sharktooth Hill. This absence may be due to taphonomic or paleoenvironmental factors. The new “Topanga” record presented here was integrated into an overview of the late Oligocene through early Pleistocene pinniped faunas of Southern California. The results show an overall increase in body size over time until the Pleistocene. Furthermore, desmatophocids were the largest pinnipeds during the middle Miocene, but were extinct by the beginning of the late Miocene. Odobenids diversified and became the dominant pinnipeds in late Miocene through Pleistocene assemblages, usually approaching or exceeding 3 m in body length, while otariids remained as the smallest taxa. This pattern contrasts with modern assemblages, in which the phocidMirounga angustirostrisis the largest pinniped taxon in the region, odobenids are extinct and medium and small size ranges are occupied by otariids or other phocids.
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Rodriguez, Diego H., and Ricardo O. Bastida. "THE SOUTHERN SEA LION, OTARIA BYRONIA OR OTARIA FLAVESCENS?" Marine Mammal Science 9, no. 4 (October 1993): 372–81. http://dx.doi.org/10.1111/j.1748-7692.1993.tb00470.x.
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Boness, Daryl J., and John M. Francis. "The Effect of Thermoregulatory Behaviour On the Mating System of the Juan Fernández Fur Seal, Arctocephalus Philippii." Behaviour 119, no. 1-2 (1991): 104–26. http://dx.doi.org/10.1163/156853991x00391.
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AbstractRecent studies of fur seals and sea lions (Otariids) which are cold water adapted, indicate that social behaviour in hotter climes is constrained by the form and availability of cool substrate provided by the rookery environment. This first study of the behaviour of the Juan Fernández fur seal provides new evidence of this relationship and the extent to which thermoregultory requirements can affect social behaviour in pinnipeds. Females of this species on Alejandro Selkirk Island made daily movements from inland pupping and rest sites to the shoreline and into the water in response to rapid increases in solar radiation to levels exceeding 1.3 cal/cm2/min. Thirty percent of these females floated and groomed offshore in the afternoon in areas protected from the surf by offshore islets and rocky reefs. Males held territories on land either along the shoreline (39%) or in land-locked areas (45%) as is typical of fur seals, or held completely aquatic territories (16%) that encompassed the site where females floated. The average aquatic male, present on territory primarily during the afternoon hours when females floated offshore, achieved as many copulations as did the average land-locked or shoreline male. Land-locked males often abandoned their territories for short periods (45 minutes on average) in response to increasing solar radiation in the afternoon and at a time when female numbers on land were low. The existence of aquatic territoriality as a successful mating strategy has not yet been documented for any other otariid. The occurrence of this behavioural strategy is likely a product of the interaction of thermoregulatory constraints and topographical features which together promote predictable aggregations of females offshore. This study further substantiates that constraints on female aggregation appear to dictate the range and mode of male mating strategies in otariids.
Dissertations / Theses on the topic "Otarid"
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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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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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Previous issue date: 2009We 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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Previous issue date: 2009-03-10Neste 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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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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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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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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Previous issue date: 2012-03-15This 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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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 écologiquesThe 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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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.
Books on the topic "Otarid"
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Henshūbu, Burū Gaido. Sapporo, Otaru, Hakodate. 4th ed. Tōkyō: Jitsugyo no Nihonsha, 2012.
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Otani, Sanshi. Otani Sanshi chosakushū. [Hatogaya-shi]: Hatogaya-shi Kyōiku Iinkai, 1988.
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Otaru Shōka Daigaku. Hyakunenshi Hensanshitsu. Otaru Shōka Daigaku hyakunenshi. Otaru-shi: Otaru Shōka Daigaku Shuppankai, 2011.
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Bijutsukan, Shiritsu Otaru. Shiritsu Otaru Bijutsukan kaikan 10-shūnen kinenshi: Otaru Municipal Art Museum. Otaru-shi: Shiritsu Otaru Bijutsukan, 1990.
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Haulena, Martin. "Otariid Seals." In Zoo Animal and Wildlife Immobilization and Anesthesia, 661–72. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118792919.ch47.
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Gentry, Roger L. "Otariid Ethology: One Researcher’s Historical Perspective." In Ethology and Behavioral Ecology of Otariids and the Odobenid, 3–20. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-59184-7_1.
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Crespo, Enrique Alberto, Larissa Rosa de Oliveira, and Maritza Sepúlveda. "South American Sea Lion (Otaria flavescens, Shaw 1800)." In Ecology and Conservation of Pinnipeds in Latin America, 93–118. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63177-2_6.
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Hanke, Frederike D., Colleen Reichmuth, and Peter Cook. "The Sensory World of Otariids." In Ethology and Behavioral Ecology of Otariids and the Odobenid, 305–21. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-59184-7_16.
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Franco-Trecu, Valentina. "Intergeneric Fertile Hybridization in Otariids." In Ethology and Behavioral Ecology of Otariids and the Odobenid, 243–47. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-59184-7_12.
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Altenbach, Holm, and George Jaiani. "Oniashvili, Otar." In Encyclopedia of Continuum Mechanics, 1969–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 2020. http://dx.doi.org/10.1007/978-3-662-55771-6_369.
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Altenbach, Holm, and George Jaiani. "Oniashvili, Otar." In Encyclopedia of Continuum Mechanics, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2019. http://dx.doi.org/10.1007/978-3-662-53605-6_369-1.
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Chotiwari-Jünger, Steffi. "Tschiladse, Otar." In Kindlers Literatur Lexikon (KLL), 1. Stuttgart: J.B. Metzler, 2020. http://dx.doi.org/10.1007/978-3-476-05728-0_21721-1.
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Charrier, Isabelle. "Vocal Communication in Otariids and Odobenids." In Ethology and Behavioral Ecology of Otariids and the Odobenid, 265–89. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-59184-7_14.
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Kawakami, H., H. Suwa, H. Marui, O. Sato, and K. Izumi. "The Otari debris flow disaster occurred in December 1996." In Slope Stability Engineering, 1379–84. London: Routledge, 2021. http://dx.doi.org/10.1201/9780203739600-130.
Full textConference papers on the topic "Otarid"
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Gerpe, M., D. Rodriguez, J. Moreno, R. Bastida, and J. Aizpun. "Heavy metal distribution in southern Sea Lions (Otaria flavescens) from Argentina." In Sea Lions of the World. Alaska Sea Grant, University of Alaska Fairbanks, 2006. http://dx.doi.org/10.4027/slw.2006.04.
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Huckstadt, L. A., and T. Antezana. "The diet of Otaria flavescens in Chile: What do we know?" In Sea Lions of the World. Alaska Sea Grant, University of Alaska Fairbanks, 2006. http://dx.doi.org/10.4027/slw.2006.07.
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Muller, G., R. P. Wilson, F. Quintana, and C. Campagna. "Three-dimensional diving behavior of a South American sea lion (Otaria flavescens)." In Sea Lions of the World. Alaska Sea Grant, University of Alaska Fairbanks, 2006. http://dx.doi.org/10.4027/slw.2006.18.
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Arnould, J. P. Y., and D. P. Costa. "Sea lions in drag, fur seals incognito: Insights from the otariid deviants." In Sea Lions of the World. Alaska Sea Grant, University of Alaska Fairbanks, 2006. http://dx.doi.org/10.4027/slw.2006.22.
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Yang, Chang-Yi, Xiao-Xiao Zhao, Fu-Le Li, and Zhi-Hua Wang. "OTACAD: An opamp synthesis tool based on simulation and lookup table." In 2010 10th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT). IEEE, 2010. http://dx.doi.org/10.1109/icsict.2010.5667430.
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Alava, J. J., and S. Salazar. "Status and conservation of otariids in Ecuador and the Galápagos Islands." In Sea Lions of the World. Alaska Sea Grant, University of Alaska Fairbanks, 2006. http://dx.doi.org/10.4027/slw.2006.31.
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A. Salameh, Walid, and Mohammed A. Otair. "Online Handwritten Character Recognition Using an Optical Backpropagation Neural Networks." In InSITE 2005: Informing Science + IT Education Conference. Informing Science Institute, 2005. http://dx.doi.org/10.28945/2932.
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There are many successful applications of Backpropagation (BP) for training multilayer neural networks. However, they have many shortcomings. Learning often takes insupportable time to converge, and it may fall into local minima at all. One of the possible remedies to escape from local minima is using a very small learning rate, but this will slow the learning process. The proposed algorithm is presented for the training of multilayer neural networks with very small learning rate, especially when using large training set size. It can apply in a generic manner for any network size that uses a backpropgation algorithm through optical time. This paper studies the performance of the Optical Backpropagation algorithm OBP (Otair & Salameh, 2004a, 2004b. 2005) on training a neural network for online handwritten character recognition in comparison with backpropagation BP.
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Hoffman, Paul F., Eric J. Bellefroid, Eben Blake Hodgin, Malcolm S. W. Hodgskiss, Glenn R. Jasechko, Benjamin W. Johnson, Kelsey Lamothe, and Samuel J. C. LoBianco. "WHY ARE CRYOGENIAN GLACIAL DEPOSITS ARE LOCALLY THICK, WHILE REGIONALLY THIN?: CASE STUDIES FROM THE OTAVI GROUP OF NAMIBIA." In GSA Annual Meeting in Denver, Colorado, USA - 2016. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016am-276796.
Full textReports on the topic "Otarid"
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Romero, M. Alejandra, M. Florencia Grandi, Juan Ignacio T�nez, C�sar A. Gribaudo, Laura M. Reyes, Mariela Dassis, Natalia PasoViola, and Javier Negrete. Otaria flavescens. En: SAyDS�SAREM (eds.) Categorizaci�n 2019 de los mam�feros de Argentina seg�n su riesgo de extinci�n. Ciudad Aut�noma de Buenos aires: Lista Roja de los mam�feros de Argentina, November 2019. http://dx.doi.org/10.31687/saremlr.19.155.
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