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1
Hennen, Daniel Reneau. "The Steller Sea Lion (Eumetopias jubatus) Decline and the Gulf of Alaska / Bering Sea Commercial Fishery." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/hennen/HennenD1204.pdf.
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The Steller sea lion (SSL) population in Alaska was listed as threatened under the Endangered Species Act in 1991. Several procedural restrictions were placed on the commercial fisheries of the region at that time in an effort to reduce the potential for human induced mortality on sea lions. Several years have elapsed since these restrictions were put into place and questions about their efficacy abound. In an effort to determine whether or not fisheries interventions have helped the SSL population to recover, estimates of the fishing activity of the Bering Sea/ Gulf of Alaska commercial fisheries in the vicinity of individual Steller sea lion rookeries and SSL population trends at those rookeries were made using data from the National Marine Fisheries Service (NMFS) Fisheries Observer Program and Steller Sea Lion Adult Count Database. Fisheries data from 1976 - 2000 were analyzed in relation to SSL population counts from 1956 - 2001, at 32 rookeries from the endangered Western Stock. Linear regression on the principal components of the fisheries data show that a positive correlation exists between several metrics of historical fishing activity and SSL population decline. The relationship is less consistent after 1991, supporting a hypothesis that fishing closures around some of the rookeries have been effective in moderating the localized effects of fishing activity on SSL.
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Yeates, Laura Carleen. "Physiological capabilities and behavioral strategies for marine living by the smallest marine mammal, the sea otter (Enhydra lutris) /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2006. http://uclibs.org/PID/11984.
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Ferdinando, Pilar M. "Assessment of Heavy Metals in Subsistence-Harvested Alaskan Marine Mammal Body Tissues and Vibrissae." Thesis, NSUWorks, 2019. https://nsuworks.nova.edu/occ_stuetd/504.
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The coastal, indigenous communities around Alaska have subsisted on marine animals for generations, often focusing on large apex predators such as seals, sea lions, and whales. Three species of pinnipeds (harbor seal, Steller sea lion, northern fur seal) and the northern sea otter have all undergone significant population declines since the 1970s, some regions more than others. Archived vibrissae (whiskers) and body tissues from these four species were available from the Bering Sea and throughout the Gulf of Alaska from the 1990s and early 2000s. Tissues from these species are exceedingly difficult to obtain; thus, the archived tissues provided a finite and irreplaceable resource of data. Analysis of these archived tissues indicates which species, tissues, and gender bioaccumulate metals more readily. In this study twelve heavy metals (arsenic, cadmium, chromium, cobalt, copper, lead, manganese, mercury, nickel, selenium, vanadium, zinc) were analyzed in vibrissae from the four select species, and in body tissues from harbor seals and Steller sea lions. The samples were collected from three regions (southeastern, southcentral, and southwestern Alaska) during the 1990s through early 2000s. Significant differences of heavy metal concentrations in vibrissae were detected among elements (p2(110) = 454.81, p2(66) = 310.88, p
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Larson, Shawn Elizabeth. "Genetic and endocrine related variability of sea otters, Enhydra lutris /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5360.
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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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Guedes, Inês Ferreira. "Patterns of colonisation in an implanted mammal carcass in the deep-Atlantic ocean." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14018.
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Mestrado em Biologia Marinha<br>Whale carcasses reaching the bottom of the ocean, known as “whale falls”,
represent massive organic inputs that provide habitat islands for complex
communities of specialised fauna. However, studies about these habitats are
mostly restricted to the Pacific Ocean. To investigate the importance of
whale falls in the deep-Atlantic Ocean, five mammal carcasses were
deployed within the CARCACE project at 1000 m depth in the Setubal
canyon (NE Atlantic, west Portuguese margin). In order to describe the fauna
associated with the carcasses, investigate the trophic ecology of the
metazoan assemblages and analyse the functional morphology of the
encountered specialists, bones resulting from the degradation of the
carcasses were collected 18 and 28 months after the deployment using a
ROV. In this context, the colonisation patterns of two dominant taxa of
invertebrates found in the colonising assemblages, the mytilid mussel “Idas”
simpsoni and Dorvilleidae polychaetes were studied. Regarding “I.” simpsoni
the specific goals of this work were to investigate its settlement patterns and
to understand its nutritional strategy. The analyses of the populations' size
structure showed a continuous settlement and a limitation in growth and
adult survival. These limitations are probably due to insufficient energy
supplied by the cow bone to maintain chemosynthesis, which is in agreement
with the isotopic signatures that indicated a higher contribution of filter
feeding than chemosynthesis to their nutrition. Concerning the dorvilleid
assemblages, the analyses of species composition disclosed temporal
variations associated with distinct food sources at different degradation
stages of the bones, as different species presented different isotopic
signatures. Moreover, species distribution in different microhabitats did not show any
relation with the substrate texture, hardness and presence of conspicuous
filamentous bacteria on the surface. The morphology of the jaw apparatus of
the different dorvilleid species was also analysed in order to investigate the
relationship between this structure and trophic ecology. Dorvilleid jaw
apparatuses are generally used in taxonomic and phylogenetic studies, but
this is the first study on the functional anatomy of these structures. Species
with similar jaw characteristics exhibited similar isotopic signatures,
suggesting a possible role of the jaw morphology in the specialisation on
different resources. However, further studies, using more species from
different habitats, are needed to establish this relationship. Overall, these
results give significant insights about the ecology of the studied species and
into the colonisation patterns of deep-sea mammal carcasses in the Atlantic
Ocean.<br>As carcaças de baleia que chegam ao fundo do oceano representam
grandes quantidades de matéria orgânica que servem de base a
comunidades complexas de fauna especializada. No entanto, a informação
disponível sobre este tipo de habitats está praticamente limitada ao oceano
Pacífico. Com o intuito de investigar a importância das carcaças de baleia no
oceano Atlântico profundo foram fundeadas, no âmbito do projeto
CARCACE, cinco carcaças de mamíferos a 1000 m de profundidade no
canhão de Setúbal (costa Portuguesa, NE Atlântico). Com o objetivo de
descrever a fauna associada às carcaças, investigar a sua ecologia trófica e
analisar a morfologia funcional das espécies encontradas, os ossos
resultantes da degradação das carcaças foram recuperados utilizando um
ROV 18 e 28 meses após o fundeamento. Neste contexto, foi feito o estudo
de dois grupos dominantes de invertebrados recolhidos da superfície dos
ossos, os mexilhões “Idas” simpsoni e poliquetas da família Dorvilleidae. Os
objetivos específicos deste trabalho relativamente a “Idas” simpsoni,
prenderam-se com o estudo dos padrões de assentamento da espécie e
também com a compreensão da sua estratégia nutricional. A análise do
tamanho dos indivíduos das populações demonstrou um assentamento
contínuo, bem como restrições no crescimento e sobrevivência dos adultos.
Estas limitações devem-se, possivelmente, ao facto de os ossos de vaca
não disponibilizarem energia suficiente para a realização de quimiossíntese,
o que é corroborado pelas análises isotópicas que sugeriram uma maior
contribuição da filtração na estratégia nutricional de “Idas” simpsoni. Relativamente à análise da composição das espécies de dorvileídeos esta
revelou variações temporais associadas a diferentes fontes de alimentação,
o que está de acordo com os resultados da análise dos isótopos estáveis
das diferentes espécies, que demonstraram assinaturas isotópicas distintas
associadas a cada espécie. Para além disso, a distribuição dos dorvileídeos
por diferentes microhabitats não demonstrou qualquer relação com a
textura, dureza e a presença de bactérias filamentosas na superfície do
substrato. A morfologia do aparelho bocal das diferentes espécies de
dorvileídeos foi também analisada com o intuito de investigar a relação entre
esta estrutura e ecologia trófica das espécies. O aparelho bocal dos
dorvileídeos é, geralmente, utilizado em estudos taxonómicos e
filogenéticos, mas o presente estudo constitui a primeira abordagem à
anatomia funcional destas estruturas. Espécies com aparelhos bocais
semelhantes exibiram assinaturas isotópicas semelhantes, sugerindo uma
possível influência da morfologia desta estrutura na especialização de cada
espécie em diferentes recursos. No entanto, para estabelecer uma relação
direta entre estes dois fatores, será necessário fazer um estudo mais
aprofundado, utilizando outras espécies provenientes de outros habitats. No
geral, os resultados obtidos neste trabalho, revelam características
importantes da ecologia das espécies estudadas, bem como dos padrões de
colonização de carcaças de mamíferos no Oceano Atlântico profundo.
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Vice, President Research Office of the. "Sea Change." Office of the Vice President Research, The University of British Columbia, 2009. http://hdl.handle.net/2429/9510.
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Wierucka, Kaja. "Multimodal mother-offspring recognition in the Australian sea lion, Neophoca cinerea." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS432.
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La reconnaissance joue un rôle important dans les systèmes de communication animale et plusieurs modalités sensorielles sont impliquées à cette fin. Bien que la reconnaissance mère-jeune ait été largement étudiée, il y a un manque d'information sur la reconnaissance multimodale et l'importance relative des différentes modalités dans ce processus. Dans cette thèse, j'ai exploré la communication multimodale chez un mammifère colonial - le lion de mer Australien (Neophoca cinerea). La reconnaissance mère-jeune est connue pour être multimodale chez cette espèce, mais les processus sous-jacents de la reconnaissance olfactive et visuelle, ainsi que les interactions entre les indices acoustiques, visuels et olfactifs, et leurs contributions relatives restent inconnues. Des analyses chimiques ont permis de déterminer si les profils chimiques diffèrent selon le sexe et l'âge, les colonies et les régions corporelles des animaux. La présence de similarités chimiques entre la mère et son petit suggèrent que l'appariement des phénotypes pourrait être utilisé pour la reconnaissance olfactive. J'ai examiné le rôle des indices visuels lors de la reconnaissance mère-jeune et j'ai constaté que les indices visuels spécifiques à l'âge sont utilisés par les femelles pour affiner la recherche de leur petit dans la colonie. Les jeunes ont également la capacité de distinguer divers indices visuels, qui peuvent être utilisés pour identifier les différentes classes de congénères. Enfin, j’ai pu aussi déterminer comment les indices acoustiques, olfactifs et visuels sont utilisés de manière synergique dans le processus d’identification individuel, et les résultats sont interprété dans une perspective coûts-avantages pour démêler les pressions évolutives sur chaque composante de ce système de communication. Si les différents indices sensoriels ont la capacité de transmettre des informations en isolation, leur rôle peut être différent lorsque d'autres indices sensoriels sont présents. Les résultats de cette recherche fournissent des résultats sans précédent, contribuant à une meilleure compréhension de la reconnaissance mère-jeune chez les mammifères, ainsi que des règles générales de communication chez les vertébrés<br>Recognition plays an important role in animal communication systems and individuals often employ different sensory modalities to enact this activity. Although recognition has been widely investigated, especially for mother-offspring interactions, there is a dearth of information about multimodal recognition and the relative importance and interactions of various sensory cues. In this thesis, I explored multimodal communication in a colonial mammal – the Australian sea lion (Neophoca cinerea). Communication during mother-pup reunions is known to be multimodal in this species, yet the underlying processes of olfactory and visual recognition, as well as the interactions between acoustic, visual and olfactory cues remain unclear. Through chemical analyses, I determined whether chemical profiles differ among sex and age classes, colonies, and body regions of animals. Chemical similarities between mothers and pups indicate that phenotype matching may be used by Australian sea lions for olfactory recognition. I examined the role of visual cues in mother-pup recognition and found that age-specific visual cues assist mothers to refine their search for their offspring in the colony. Pups are capable of distinguishing various visual cues that can be used in the assessment of conspecifics. Having provided baseline information about the role of sensory cues in isolation, I determined how acoustic, olfactory, and visual cues are used in a synergistic way to ensure accurate mutual recognition and then interpreted the results using a cost-benefit perspective to disentangle the evolutionary pressures on each component of this communication system. I showed that although cues have the ability to convey given information in isolation, their role may be different when other sensory cues are present. Furthermore, there is a mutual dependency in the communication system, where the limitations imposed on one participant of the dyad affect cue use by the other. These findings contribute to a better understanding of mammal mother-offspring recognition and communication mechanisms in vertebrates
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French, John. "Satellite technology for tracking birds and sea mammals." Thesis, University of Aberdeen, 1986. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU362526.
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Burgeoning world communication networks indicate a period of intense investment in space technology, this makes it a good point in time to pose the question: Is there a satellite location system capable of remotely recording the track of an electronics package made small enough for a bird to carry? Clearly a solution for birds will considerably advance the possibility of tracking other wildlife and indeed almost any artefact. The laws of nature give a finite working lifetime to all earth satellites. This and the steady advance of technology means that satellite systems are deployed and fade from use over a single decade. While replacements for those that malfunction or become exhausted can be launched, improved concepts consistently make periodic system replacement more worthwhile. Among the currently available satellite systems capable of positioning, the Argos data collection and location system is the most suitable for wildlife tracking. A short explanation of Doppler positioning is given and examples of data from remote sensing satellites show some of the background data available. I have briefly cited early studies on Elk, Polar bears, Dolphins, Turtles, Basking shark and Humpback whales. Design work for the bird location package begins in section 3. An experimental harness is tested together with a lightweight pure nickel case for the electronic assembly. Environment effects are considered and wind tunnel tests are made to determine drag and heat loss. Sub-sections 3-1 to 3- 8 complete the work as follows:- High stability oscillator. A circuit with acceptable performance and minimal power input is evolved by investigation of each component. RF power circuits and phase modulator designed for minimal part count are described. Digital encoder, required to generate the PTT identity code etc is described, it uses microminiature components and a CMOS field programmable ROM. A developed version for sensor data input is also described. Antenna, this is designed using a model bird filled with a fluid having similar permittivity and conductivity to living tissue. Impedance and field patterns are measured using a signal source, vector voltmeter, reflectometer, spectrum analyser and specialised test equipment. Power is derived from lithium cells as a result of pulse testing to identify the best type; solar arrays are also investigated. Possible behavioural aberrations due to RF emissions are considered as the RF pulse power is 30 dBs (1000 times) higher than conventional equipment at VHF. It is shown that avian heart-rate is not affected by the RF pulse. Results and conclusions Solutions to engineering problems encountered in applying the design to birds, seals and whales are shown to be successful by the results of field trials. Appendices outline supporting work.
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Miller, Natalie J. "The evolution of a physiological system the pulmonary surfactant system in diving mammals /." Connect to this title online, 2005. http://hdl.handle.net/2440/37717.
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Pulmonary surfactant is a complex mixture of lipids and proteins that lowers surface tension, increases lung compliance, and prevents the adhesion of respiratory surfaces and pulmonary oedema. Pressure can have an enormous impact on respiratory function, by mechanically compressing tissues, increasing gas tension resulting in increased gas absorption and by increasing dissolved gas tensions during diving, resulting in the formation of bubbles in the blood and tissues. The lungs of diving mammals have a huge range of morphological adaptations to enable them to endure the extremely high pressures associated with deep diving. Here, I hypothesise that surfactant will also be modified, to complement the morphological changes and enable more efficient lung function during diving. Molecular adaptations to diving were examined in surfactant protein C (SP-C) using phylogenetic analyses. The composition and function of pulmonary surfactant from several species of diving mammals was examined using biochemical assays, mass spectrometry and captive bubble surfactometry. The development of surfactant in one species of diving mammal (California sea lion), and the control of surfactant secretion using chemical and mechanical stimuli were also determined. Diving mammals showed modifications to SP-C, which are likely to lead to stronger binding to the monolayer, thereby increasing its fluidity. Phospholipid molecular species concentrations were altered to increase the concentration of more fluid species. There was also an increase in the percentage of alkyl molecular species, which may increase the stability of the monolayer during compression and facilitate rapid respreading. Levels of SP-B were much lower in the diving species, and cholesterol was inversely proportional to the maximum dive depth of the three species. Surface activity of surfactant from diving mammals was very poor compared to surfactant from terrestrial mammals. The newborn California sea lion surfactant was similar to terrestrial mammal surfactant, suggesting that these animals develop the diving-type of surfactant after they first enter the water. The isolated cells of California sea lions also showed a similar response to neuro-hormonal stimulation as terrestrial mammals, but were insensitive to pressure. These findings showed diving mammal surfactant to have a primarily anti-adhesive function that develops after the first entry into the water, with a surfactant monolayer, which would be better suited to repeated collapse and respreading.<br>Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2005.
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Delannoy, Christian M. J. "Host adaptation of aquatic Streptococcus agalactiae." Thesis, University of Stirling, 2013. http://hdl.handle.net/1893/17259.
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Streptococcus agalactiae is a pathogen of multiple hosts. The bacterium, an aetiological agent of septicaemia and meningo-encephalitis in freshwater and saltwater fish species, is considered a major threat to the aquaculture industry, particularly for tilapia. Cattle and humans are however the main known reservoirs for S. agalactiae. In humans, the bacterium (commonly referred to as Group B Streptococcus or GBS) is a member of the commensal microflora of the intestinal and genito-urinary tracts, but it is also a major cause of neonatal invasive disease and an emerging pathogen in adults. In cattle, S. agalactiae is a well-recognized causative agent of mastitis. Numerous studies focusing on S. agalactiae from human and bovine origins have provided insight into the population structure of the bacterium, as well as the genome content and pathogenic mechanisms through identification of virulence determinants. Concerning S. agalactiae from aquatic origins, scientific information mainly focused on case reporting and/or experimental challenges, with a limited or absence of information in terms of pathogenesis, virulence determinants and genotypes of the strains involved. The objective of this study was to enhance our understanding of the molecular epidemiology, host-adaptation and pathogenicity of S. agalactiae in aquatic species, with particular emphasis on tilapia. Firstly, a collection of 33 piscine, amphibian and sea mammal isolates originating from several countries and continents was assembled, with the aim of exploring the population structure and potential host specificity of aquatic S. agalactiae. Isolates were characterised using pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), and a standardised 3-set genotyping system comprising molecular serotypes, surface protein gene profiles and mobile genetic element profiles. Two major subpopulations were identified in fish. The first subpopulation consisted of non-haemolytic isolates that belonged to sequence type (ST) 260 or 261, which are STs that have been reported only from teleosts. These isolates exhibited a low level of genetic diversity by PFGE and clustered with other STs that have been reported only in fish. Another common feature was the absence of all surface protein genes or mobile genetic elements targeted as part of the 3-set genotyping and that are usually found in human or bovine isolates. The second subpopulation consisted of β-haemolytic isolates recovered from fish, frogs and sea mammals, and that exhibited medium to high genetic diversity by PFGE. STs identified among these isolates have previously been identified from strains associated with asymptomatic carriage and invasive disease in humans. The human pathogenic strain ST7 serotype Ia was detected in fish from Asia. Moreover, ST283 serotype III-4 and its novel single locus variant ST491 detected in fish from Southeast Asia shared a 3-set genotype identical to that of an emerging ST283 clone associated with invasive disease of adult humans in Asia. These observations suggested that some strains of aquatic S. agalactiae may present a zoonotic or anthroponotic hazard. STs found among the seal isolates (ST23) have also been reported from humans and numerous other host species, but never from teleosts. This work provided an excellent basis for exploration of the virulence of selected strains in experimental challenges. The virulence of two strains of S. agalactiae was experimentally investigated by intra-peritoneal infection of Nile tilapia (Oreochromis niloticus), using an isolate originally recovered from fish and belonging to ST260, and an isolate originating from a grey seal and belonging to ST23. The clinical signs, the in vivo distribution of viable bacteria and bacterial antigens, and the gross and histopathological lesions that developed during the time course of the infection were investigated. The ST260 strain was highly virulent, whereas no major clinical sign or mortalities occurred in the fish challenged with the ST23 strain. After injection, both strains however gained access to the bloodstream and viable bacteria were recovered from all organs under investigation. During the early stages of infection, bacteria were mostly found within the reticulo-endothelial system of the spleen and kidney. Thereafter, the ST260 demonstrated a particular tropism for the brain and the heart, but granulomatous inflammation and associated necrotic lesions were observed in all organs. ST23 was responsible for a mixed inflammatory response associated with the presence of bacteria in the choroid rete and in the pancreatic tissue only. After 7 days post-challenge and for both strain, the formation or containment of bacteria within granulomata or other encapsulated structures appeared to be a major component of the fish response. However, the load of viable bacteria remained high within organs of fish infected with ST260, suggesting that, unlike ST23, this strain is able to survive within macrophages and/or to evade the immune system of the fish. This work demonstrates that the lack of report of ST23 strains in fish is possibly not due to a lack of exposure but to a lack of virulence in this host. The two strains, which differ in prevalence and virulence in fish, provide an excellent basis to investigate genomic differences underlying the host-association of distinct S. agalactiae subpopulations. The genome of the ST260 strain used in challenge studies was sequenced. We therefore provided the first description for the genome sequence of a non-haemolytic S. agalactiae isolated from tilapia (strain STIR-CD-17) and that belongs by multi-locus sequence typing (MLST) to clonal complex (CC) 552, which corresponds to a presumptive fish-adapted subgroup of S. agalactiae. The genome was compared to 13 S. agalactiae genomes of human (n=7), bovine (n=2), fish (n=3) and unknown (n=1) origins. Phylogenetic analysis based on the core genome identified isolates of CC552 as the most diverged of all S. agalactiae studied. Conversely, genomes from β-haemolytic isolates of CC7 recovered from fish were found to cluster with human isolates of CC7, further supporting the possibility that some strains may represent a zoonotic or anthroponotic hazard. Comparative analysis of the accessory genome enabled the identification of a cluster of genes uniquely shared between CC7 and CC552, which encode proteins that may provide enhanced fitness in specific niches. Other genes identified were specific to STIR-CD-17 or to CC552 based on genomic comparisons; however the extension of this analysis through the PCR screening of a larger population of S. agalactiae suggested that some of these genes may occasionally be present in isolates belonging to CC7. Some of these genes, occurring in clusters, exhibited typical signatures of mobile genetic elements, suggesting their acquisition through horizontal gene transfer. It is not possible to date to determine whether these genes were acquired through intraspecies transfer or through interspecies transfer from the aquatic environment. Finally, general features of STIR-CD-17 highlighted a distinctive genome characterised by an absence of well conserved insertion sequences, an abundance of pseudogenes, a smaller genomic size than normally observed among human or bovine S. agalactiae, and an apparent loss of metabolic functions considered conserved within the bacterial species, indicating that the fish-adapted subgroup of isolates (CC552) has undergone niche restriction. Finally, genes encoding recognised virulence factors in human S. agalactiae were selected and their presence and structural conservation was evaluated within the genome of STIR-CD-17.
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Gomes, J?nior Jos? Edilson. "Purifica??o e caracteriza??o de uma ?-N-acetillhexosaminadase extra?da do mam?fero marinho Sotalia fluviatilis." Universidade Federal do Rio Grande do Norte, 2006. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12612.
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Previous issue date: 2006-12-06<br>This report shows 2232 times purification of a βNAcetylhexosaminidase from hepatic extracts from the sea mammal Sotalia fluviatilis homogenate with final recovery of 8,4%. Sequenced steps were utilized for enzyme purification: ammonium sulfate fractionation, Biogel A 1.5 m, chitin, DEAESepharose and hydroxyapatite chromatographies. The protein molecular mass was estimated in 10 kDa using SDSPAGE and confirmed by MALDITOF. It was found to have an optimal pH of 5.0 and a temperature of 60?C. Using pnitrophenylNAcetylβDglycosaminide apparent Km and Vmax values were of 2.72 mM and 0.572 nmol/mg/min, respectively. The enzyme was inhibited by mercury chloride (HgCl2) and sodium dodecil sulfate (SDS)<br>Este trabalho mostra a purifica??o de 2232 vezes de uma βNAcetilhexosaminidase obtida a partir dos extratos hep?ticos do mam?fero marinho Sotalia fluviatilis com recupera??o final de 8,4%. Passos seq?enciais foram utilizados para a purifica??o enzim?tica: fracionamento com sulfato de am?nio e as cromatografias de Biogel A 1.5 m, Quitina, DEAESepharose e Hidroxiapatita. A massa molecular prot?ica foi estimada em 10 kDa usando SDSPAGE e confirmada por MALDITOF. Foi encontrado como pH e temperatura ?timos, 5,0 e 60?C, respectivamente. Os valores de Km e Vm?x aparentes foram 2,72 mM e 0,572 nmol/mg/min, sendo utilizado o pnitrofenilNAcetilβDglicosamin?deo como substrato. A enzima foi inibida pelo cloreto de merc?rio (HgCl2) e dodecil sulfato de s?dio (SDS)
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Guldager, Nikolina. "Effects of an Increasing Harbor Seal Population on Changes in Sites Used for Pupping." Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/GuldagerN2001.pdf.
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Negro, Sandra Silvia. "Reproductive ecology and life history trade-offs in a dimorphic polygynous mammal, the New Zealand fur seal." Thesis, University of Canterbury. School of Biological Sciences, 2008. http://hdl.handle.net/10092/2505.
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Polygyny is the most common mating system in mammalian species (95%), yet our understanding of polygynous systems and microevolutionary processes is still limited. Pinniped mating systems range from extreme polygyny (e.g. elephant seals) to sequential female defence by males and hence have often been used as models for mating system studies. Parentage analysis has enabled the examination of mating success, the identification of pedigrees, and the elucidation of social organisation, greatly enhancing our understanding of mating systems (Chapter 1). However, such analyses are not without pitfalls, with erroneous assignments common in open systems (i.e. when parental and offspring samplings are incomplete). We investigated the effects of the user-defined parameters on the accuracy of parental assignment using two commonly used parental allocation programme, CERVUS and PASOS (Chapter 2). We showed that inaccurate user-defined parameters in CERVUS and PASOS can lead to highly biased output e.g. the assignment rate at 95% CL of offspring with a sampled known mother to sampled males decreased from 58% to 32% when the proportion of candidate males sampled in the parameter options decreasing 4-fold. We found that the use of both CERVUS and PASOS for parentage assignment can increase the likelihood of correctly allocating offspring to sampled parents to 97% in our study system. Incorrect parental assignment can bias estimates of various biological parameters, such as lifetime reproductive success and mate choice preference, and hence bias ecological and evolutionary interpretations. Here, we propose solutions to increase the power of parentage assignment and hence decrease the bias in biological parameter estimates. In addition, we analysed the effects of the intrinsic bias in likelihood assignment approaches towards assigning higher probability of parentage on individuals with rare alleles and those with heightened offspring-parent matches, which increase with the number of homozygous loci (Chapter 3). We showed that, as a consequence of the algorithms employed in the programmes CERVUS and PASOS, heterozygote males with rare genotypes are assigned higher rates of parentage than males with common alleles. Consequently, where two males could both be biological fathers of a given offspring, parentage assignment will more often go to the male with the rarer alleles (most often in heterozygous loci). Thus, the commonly used parentage assignment methods may systematically bias the results of parentage analyses towards supporting the notion that females prefer more genetically unusual, most often heterozygous, males. Such a bias may sway investigators towards incorrectly supporting the concept that females choose genetically more unusual males for heterozygosity fitness benefits that underpin the good genes hypothesis, when in fact no such relationship may exist. In polygynous mammals, successful males mate with multiple females by competing with and limiting the access of other males to females. When the status of many males (age, size, health, genetic etc.) prevents them from achieving the primary mating tactic, theory predicts selection for a diversification of male mating tactics. Recent studies in pinnipeds have shown that observed male mating success was correlated to male paternity success in some species (elephant-seals), but not in others (grey seals). The existence of alternative mating strategies can explain those discrepancies. Chapter 4 implemented the guidelines provided in Chapter 2 and 3 and focused on the polygynous New Zealand fur seal Arctocephalus forsteri, predicting that 1) competition for females is likely to cause a diversification of male mating tactics; and 2) that alternative tactics can yield reproductive success. Our results indicated three male behavioural profiles; one corresponded to large territorial males and two illustrated a continuum of alternative tactics employed by non-territorial subordinate males. Our study highlights that holding a territory is not a necessary condition for reproductive success in a population of otariids. The degree of sexual size dimorphism in polygynous species is expected to increase with the degree of intra-sexual competition and in turn with the degree of polygyny. The life history of an individual is the pattern of resource allocations to growth, maintenance, and reproduction throughout its lifetime. Both females and males incur viability costs of mating and reproduction. However, male viability costs due to increase growth and male-male competition can be greater than female viability costs of mate choice and reproduction. Although an abundant literature on sexual dimorphism in morphology, physiology, and parasite infections is available, little is known on the intra-sexual differences in physiology and parasite infections associated to the reproductive success of different mating strategies in mammalian species. Chapter 5 examined the reproductive costs between territorial and subordinate males New Zealand fur seal related to their relative reproductive success using a multidisciplinary approach (behaviour, genetics, endocrinology, parasitology). We found that dominant New Zealand fur seal males endure higher reproductive costs due to the direct and indirect effects of high testosterone levels and parasite burdens. Our study highlights that holding a territory confers a higher reproductive success, but induces higher costs of reproduction that may impair survival. Understanding microevolutionary processes associated to polygynous systems is fundamental in light of the ongoing anthropogenic alteration of the environment through climatic variations and habitat reduction which ultimately affect opportunity for sexual selection and shape the life history trade-offs.
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Gallon, Susan Louise. "Foraging strategies in grey seals (Halichoerus grypus) : foraging effort and prey selection." Thesis, St Andrews, 2008. http://hdl.handle.net/10023/704.
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Cate, Jenipher Rose. "The effects of tourism on the behaviour of the New Zealand fur seal (Arctocephalus forsteri)." Thesis, University of Canterbury. Biological Sciences, 2013. http://hdl.handle.net/10092/8724.
Full textAbstract:
The demand by ecotourism for easily accessible wildlife encounters has increased the need for regulations to minimise negative effects of tourism on towards marine mammals. High levels of human interaction could have serious consequences for recovering populations of New Zealand fur seals (Arctocephalus forsteri). By monitoring behavioural shifts in reactions to human disturbance, the aim of this study was to determine how disturbance by tourism is affecting the behaviour of the New Zealand fur seals. Fur seal breeding colonies, haul-outs, and a pup nursery were studied on the South Island to determine the level of disturbance. Data collected in this study can be used towards improving monitoring regimes to mitigate negative effects of anthropogenic disturbance. I first used behavioural observations to assess a seal’s behaviour in response to different types of tourist activities. Next, I examined changes in New Zealand fur seal behaviour as a result of visits to colonies by tourist boats. To quantify the response of fur seals to tourist boats, experimental boat approaches were conducted using a before, during, and after instantaneous scan sampling method at two breeding colonies (one with high vessel traffic and one with none). Impact of noise was also investigated using a loud speaker to mimic local harbour tours. Lastly, behavioural observations on seal pups at a nursery were conducted comparing pup behaviour in the presence and absence of tourism along with variable intensities of tourist behaviour. My observations suggest that seal behaviour was significantly different between sites with and without tourist visits. The type of tourism had a significant effect on the behavioural state of seals, with animals more active when there were people walking in the colonies. There were also signs of habituation in some of the study colonies. Since each colony varied in the type of tourism it experienced, it is possible that it is not only the level of tourism that is important but also the type of tourism that has a significant role in eliciting short-term behavioural shifts. Observations from a tour boat revealed an increase in the percentage of seals reacting when vessels were close to the shore. This distance effect was overridden and reactions were greater, however, when tours included commentary via an external speaker. The effects of both distance and noises were significantly different between colonies with high and low levels of tourist visits. Due to the overlap of peak tourist visits with fur seal breeding season, these animals are at their most vulnerable when companies are in peak operation. Finally, as with adults, pup behaviour was also significantly affected by tourism presence. Periods of inactivity and awareness increased in the presence of tourists, which is indicative of disruption of “play” and movement towards more vigilant behaviour. Despite the significant effects of tourist visits I found in this study, there was large variation in the degree of responses in different populations of the fur seal. This variation is thought to be due, in part, by the level of desensitisation, especially at locations with high or continual tourism pressures. This study also provides evidence that fur seal pups subject to human disturbance will alter their behaviour, shifting from active (when people are not around) to inactive and more aware (with increased disturbance). The results presented suggest such visits are not without consequences and that animals can be disturbed by human interactions. Therefore, measures should be taken at all seal colonies used in tourism ventures to mitigate any negative long-term effect on the fur seal populations.
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Wintle, Nathan J. "Total Mercury in Stranded Marine Mammals from the Oregon and Southern Washington Coasts." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/310.
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Muscle samples from 105 marine mammals stranded along the Oregon-Washington coasts (2002-2009) were tested for levels of total mercury by Cold Vapor Atomic Fluorescence Spectrometry. The total mercury present is predominantly in the form of highly toxic methylmercury. After normalizing muscle tissue to 75% water weight, due to variance in water content, Steller sea lions (Eumetopias jubatus) and northern elephant seals (Mirounga angustirostris) exhibited the highest mean concentrations of total mercury followed by harbor seals (Phoca vitulina), harbor porpoises (Phocoena phocoena), and California sea lions (Zalophus californianus); 0.34 ± 0.278, 0.34 ± 0.485, 0.21 ± 0.216, 0.17 ± 0.169 and 0.15 ± 0.126 mg/kg normalized weight, respectively. Mean normalized values demonstrated limited muscle methylmercury accumulation in these species in the Pacific Northwest. Normalizing muscle mercury concentrations eliminated variability from desiccation, and allowed for a clearer indication of the amount of mercury the animal accumulated before stranding. However, actual wet weight concentrations in some of the stranded carcasses were high enough to pose a risk to scavengers.
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Watson, Rebecca Reiko. "Immunohistochemical fiber typing, ultrastructure, and morphometry of harbor seal skeletal muscle." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/246.
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There is strong evidence that the skeletal muscles of pinnipeds are adapted for an aerobic, lipid-based metabolism under the hypoxic conditions associated with breath-hold diving. However, regional variations in mitochondrial density are unknown, and the few fiber typing studies performed on pinniped skeletal muscles are not consistent with an aerobic physiological profile. Thus, the objectives of this study were to (1) reexamine the fiber type distribution throughout the primary locomotory muscles of the harbor seal, and (2) to better understand the density and distribution of mitochondria in the locomotory muscles. Multiple samples from transverse sections of the epaxial muscles and a single sample of the pectoralis muscle of wild harbor seals were analyzed using immunohistochemical fiber typing and electron microscopy. Fiber typing results indicated that harbor seal epaxial muscles are composed of 47.4% type I (slow twitch, oxidative) fibers and 52.8%, IIa (fast twitch, oxidative) fibers. No fast twitch, glycolytic (type IIb) fibers were detected in the epaxial muscles or the pectoralis muscle. Mean volume density of mitochondria [Vv(mt,f)] was 5.6%, which is elevated over what would be predicted for a terrestrial mammal of similar mass. The elevated Vv(mt,f) had a high proportion of intermyofibrillar mitochondria, a trait not normally found in the muscles of terrestrial mammals with elevated Vv(mt,f). These results provide further evidence that the elevated mitochondrial volume density in pinniped muscle decreases the oxygen diffusion distance between myoglobin and mitochondria to facilitate aerobic respiration in working muscles. In addition, analyses of heterogeneity revealed that the regions of the epaxial muscles that were located deep within the muscle showed a significantly higher Vv(mt,f) relative to those regions that were superficially-located. In contrast, there was no significant heterogeneity of fiber type detected in either plane of the epaxial muscles. Thus, there was a fine-scale pattern of spatial heterogeneity of Vv(mt,f) within the epaxial muscles that does not manifest in fiber type distribution, indicating that the fibers have similar oxidative capacities.
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Mammen, Siju Abraham. "Techno–economic investigation into nuclear centred steel manufacturing / Mammen, S.A." Thesis, North-West University, 2011. http://hdl.handle.net/10394/7054.
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With the rising electricity, raw material and fossil fuel prices, as well as the relatively low selling price of steel, the steel industry has been put under strain to produce steel as cost–effectively as possible. Ideally the industry requires a cost–effective, stable source of energy to cater for its electricity and energy needs. Modern High Temperature Reactors are in a position to provide industries with not only electricity, but also process heat. Therefore, a study was conducted into the economic viability of centering the steel industry on nuclear power. This study considered 3 technology options: a nuclear facility to cater for solely the electricity needs of the steel industry; a nuclear facility producing hydrogen for the process needs of the steel industry; and a nuclear facility co–generating electricity and process heat for the steel industry.
An economic model for each of the 3 scenarios was developed that factored in the various cost considerations for each of the 3 options. In general, this included the construction costs, operational and maintenance cost, build time and interest rate of the financed amount. For each option, the model calculated the cost of production per unit output. The outputs were electricity for option 1, hydrogen for option 2, and both electricity and process heat for option 3. Each model was optimised based on a realistic best case scenario for the capital and operational costs and respective best case cost per unit outputs for each of the options were calculated.
Using the optimised cost model, it was shown that electricity produced from nuclear power was more cost effective than current electricity prices in South Africa. Similarly, it was shown that a nuclear facility could produce heat at a more cost–effective means than by the combustion of natural gas. Hydrogen proved to be not cost effective compared to reformed natural gas as a reducing agent for iron ore.
Based on the cost savings, a cash–flow analysis showed that the payback period for a nuclear power plant that produced electricity for the steel industry would be around 12 years at 0% interest and 15 years at 5% interest. Due to the long payback period and lack of certainty in the steel industry, any steel manufacturer would opt for purchasing electricity from a nuclear based electricity utility rather than building a facility themselves. Savings of over $70 million/year were achievable for a 2 million tonne/year electric arc furnace.
Overall this analysis showed that electricity generation is the only viable means for nuclear power to be integrated with the steel manufacturing industry.<br>Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2012.
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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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Mizuguchi, Daisuke. "Underwater vocal repertoire and their function in three ice-breeding seals in the Arctic." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215373.
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Robinson, Kelly J. "The role of oxytocin in the maternal behaviour of the grey seal (Halichoerus grypus)." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/7057.
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The neuropeptide hormone oxytocin plays an integral role in mammalian reproductive endocrinology and behaviour. It has been utilised to study the physiological factors driving maternal behaviour in both laboratory and domestic mammals, but few studies have successfully detected oxytocin in wild individuals, or linked detected concentrations to the behaviours they exhibit. Phocid seals present an excellent system in which to study oxytocin's effects on maternal behaviour in the wild. The energetic constraints placed on a phocid mother during the dependant period should cause strong selection pressure for behaviour that maximises reproductive success with the least cost to the mother. However in many phocid species, substantial variations in maternal behaviour persist. In order to investigate whether oxytocin plays a role in driving this variation, behavioural and hormonal datasets were collected from grey seal mothers and pups on two breeding colonies in Scotland. A protocol for the detection of plasma oxytocin in phocid seals was successfully developed, along with the methodology to manipulate peripheral oxytocin concentrations to directly test the hormone's impact on behaviour. Both correlatory studies on natural oxytocin concentrations and behaviour in wild mother-pup pairs and manipulation experiments on newly weaned pups show that plasma oxytocin concentrations influence behaviours that makes mother – pup separation less likely. These include increasing the time spent in close proximity to each other, increasing the number of checks performed on the pup and reducing the aggressive behaviour directed towards the other individual. Additionally, plasma oxytocin could be used as an indicator of weak maternal bonds between mother and pup, which resulted in behaviours such as abandonment and fostering. This study highlights the potential of oxytocin for studying variations in behaviours critical to an individual's reproductive success and provides the methodological framework for studies on other wild species to be conducted in the future.
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Azeria, Ermias Tesfamichael. "Community dynamics of insular biotas in space and time : the Dahlak archipelago, Red Sea, Eritrea and East African coastal forests /." Uppsala : Dept. of Conservation Biology, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/s311.pdf.
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Matos, Bárbara Cartagena da Silva. "Do sea otters according to prey's nutritional value?" Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17176.
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Mestrado em Ecologia Aplicada<br>A Teoria do Forrageio Ótimo propõe que o estímulo nutricional na escolha de presas e busca de alimento em carnívoros é o ganho energético. Em contraste, pesquisas recentes sugerem que os carnívoros selecionam presas que fornecem uma dieta com um equilíbrio específico de macronutrientes (gordura, proteína, hidratos de carbono), ao invés do maior conteúdo energético. Para este efeito, as escolhas de presas de lontras-marinhas (Enhydra lutris) que habitam Sitka Sound no sudeste do Alasca, foram estudadas durante os meses de maio a agosto de 2016. Os objetivos desta pesquisa foram: 1) descrever a dieta das lontras-marinhas em Sitka Sound; 2) descrever o valor nutricional das suas presas; 3) comparar diferenças na escolha de presas de acordo com o sexo; e 4) avaliar e comparar o valor nutricional das presas com as escolhas das lontras-marinhas. Os dados de observação foram coletados oportunisticamente, através de uma plataforma de oportunidade. As presas de lontras-marinhas foram capturadas em áreas arbitrárias de Sitka Sound, e analisadas quanto à sua percentagem em lípidos (teor de gordura) e calorias (densidade de energia). O consumo de presas foi significativamente diferente: as amêijoas foram as presas mais consumidas (68,6%), seguidos pelos ouriços-do-mar (14,3%), vieiras (5,7%), pepinos-do-mar (5,7%), caranguejos (2,9%) e estrelas-do-mar (2,9%). Além disso, os resultados revelaram uma significativa diversidade no conteúdo de gordura e densidade energética entre presas de lontra-marinha. O abalone registou maior teor de densidade energética, seguido pelas vieiras, enquanto que os ouriços-do-mar registaram maior teor em lípidos. A escolha de presas e a ingestão de nutrientes não diferiram significativamente entre machos e fêmeas, no entanto, os machos de lontras-marinhas consumiram mais moluscos do que as fêmeas, enquanto que as fêmeas consumiram mais ouriços-do-mar do que os machos. O trabalho sobre nutrição em carnívoros é preliminar, e estes resultados fornecem um ponto de partida para futuras pesquisas. As respostas a estas questões não só terão implicações significativas na gestão das populações de predadores e das comunidades ecológicas de que fazem parte, mas também acrescentarão informações importantes sobre a biologia de predadores que até agora foram negligenciadas. Além disso, os conflitos nas comunidades sobre os impactos que as lontras-marinhas têm na pesca comercial no sudeste do Alasca, não podem ser ignorados. Compreender as escolhas de presas de lontras-marinhas pode fornecer previsões de como a pesca pode ser afetada, de acordo com o crescimento da população de lontras nesta área, a fim de ajudar políticos, membros da comunidade e pescadores comerciais, a responder em conformidade.<br>Foraging theory proposes that the nutritional driver of prey choice and foraging in carnivores is energy gain. In contrast, recent research suggests that carnivores select prey that provides a diet with a specific balance of macronutrients (fat, protein, carbohydrates), rather than the highest energy content. To this effect, the prey choices of sea otters (Enhydra lutris) inhabiting Sitka Sound, in southeast Alaska, were studied during the months of May-August of 2016. The goals of this research were to 1) describe sea otter’s diet in Sitka Sound; 2) describe the nutritional value of sea otters’ prey items; 3) compare differences in prey choice according to sex; and 4) evaluate and compare prey’s nutritional value with sea otter’s prey choices. Foraging observational data were collected opportunistically on a boat-based platform of opportunity. Sea otter’s main prey were captured in arbitrary areas of Sitka Sound, and analyzed for percentage in lipids (fat content), and calories (energy density). Prey consumption was significantly different: clams were the most frequently consumed prey (68,6%), followed by sea urchins (14,3%), scallops (5,7%), sea cucumbers (5,7%), crabs (2,9%) and sea stars (2,9%). Also, the results revealed a significant diversity in content of fat and energy density between sea otter prey specimens. Abalone ranked first on content of energy density, followed by scallops, while sea urchins recorded the highest lipid content. Prey choice and nutrient intake were not significant different between male and female sea otters, nevertheless, males consumed more clams than females, while females consumed more sea urchins than males. The work on carnivore nutrition is preliminary, and these results provide a starting point for future work. Answers to such questions not only will have significant implications for managing predator populations and the ecological communities of which they are a part, but will also add important information on predator biology that has been neglected so far. Moreover, communities’ conflicts over the impacts sea otters are having on commercial shellfisheries in southeast Alaska cannot be overlooked. Understanding sea otter’s prey choices may provide information and predictions of how fisheries may be affected as the sea otter population grows in this area, in order to help decision makers, policy makers, community members, and commercial fishermen respond accordingly.
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Trites, Andrew W. "The northern fur seal : biological relationships, ecological patterns and population management." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/32173.
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Data collected from Pribilof far seals, Callorhinus ursinus, on land (1911-89) and at sea (1958-74) are analyzed to establish biological relationships and distinguish ecological patterns that are relevant to understanding and managing northern fur seal populations. The thesis follows the development of the fur seal from conception and birth through to sexual maturity and finally to a synthesis of the earlier material in terms of population regulation, management, and reasons for the decline of the Pribilof herd. Growth curves show that male fetuses grow faster and larger than female fetuses, and that fetal size is influenced by the age, size, and reproductive history of the mother. Juvenile and adult fur seals experience pronounced seasonal increases and decreases in body length and mass. Rapid gains in mass and growth occur during a brief 1-3 month period as the population migrates through the coastal waters of northern British Columbia and Alaska on its way to the Pribilof Islands. Body mass is gradually lost during the rest of the year while fasting on land and wintering along the coasts of Washington, Oregon, and California. The timing of migration and pupping is highly synchronized from year to year and may be related to the effect of climatic conditions on pup survival during the breeding season. Predictions from a thermal budget developed for pups and the results of a seasonal decomposition of weather patterns on the Pribilof Islands show that the synchronism of births in early July corresponds to the start of three months of conditions that are optimal for growth and survival of pups. Long term fluctuations are noted in
pup mass and subadult growth rates which may be related to underlying, large scale natural changes in prey abundance. Changes in the physiological condition (body growth) and vital rates (survival and reproduction) are analyzed for the period 1911-89 as the population increased and decreased. Few density dependent relationships could be demonstrated. Two hypotheses concerning the current decline of the Pribilof population are reviewed and a new, third hypothesis is proposed. The thesis also examines biases in data collection related to the effects of tagging and the handling of fur seals and outlines some directions for future research.<br>Science, Faculty of<br>Zoology, Department of<br>Graduate
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Fang, Ying. "Historical population genetics of Callorhinus ursinus (Northern fur seals) from the Aleutian Islands." View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-2/fangy/yingfang.pdf.
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Boehme, Lars. "The frontal system of the Antarctic Circumpolar Current : marine mammals as ocean explorers." Thesis, St Andrews, 2008. http://hdl.handle.net/10023/687.
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Fortuna, Caterina Maria. "Ecology and conservation of bottlenose dolphins (Tursiops truncatus) in the north-eastern Adriatic Sea." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/157.
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Hanlan, Suzanne K. "Nosing behaviour in captive harbour seals (Phoca vitulina concolor) : implications for olfaction and affiliation /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0015/MQ42389.pdf.
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Cox, Samantha Lucy. "The role of physical oceanography on the distributions and foraging behaviours of marine mammals and seabirds in shelf-seas." Thesis, University of Plymouth, 2016. http://hdl.handle.net/10026.1/4579.
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Mid-latitude shelf-seas are highly productive regions that host a rich diversity of animals including large numbers of marine mammals and seabirds. These large vertebrate predators play a crucial role in the functioning of shelf-sea ecosystems. However, the combined effects of multiple anthropogenic stressors are driving unprecedented declines in many of their populations. Mitigating this depends upon effective conservation and integrated ecosystem based approaches to management, which require a comprehensive understanding of the habitat needs of marine predators. The foraging efficiencies of marine predators are closely tied to the availability of a number of oceanographic features. As such, these physical habitats represent critical locations within a species’ range whose preservation and protection should be of high priority. The collection of studies presented in this thesis aims to improve our understanding of the physical oceanographic processes that underlie the at-sea behaviours and distributions of marine mammals and seabirds in coastal and shelf-sea environments. A combination of at-sea boat surveying, animal-borne biologging, satellite remote-sensing, passive acoustics and numerical modelling was used to collect information on the distributions and foraging behaviours of a range of marine predators alongside the bio-physical characteristics of the oceanographic habitats they occupied. These data were then used to (1) examine the use of oceanographic habitats generated around tidal-mixing fronts and coastal topographic structures by a range of piscivorous species including bottlenose dolphins Tursiops truncatus, common dolphins Delphinus delphis, harbour porpoises Phocoena phocoena and northern gannets Morus bassanus, and (2) identify the physical processes underlying their creation. Original aspects of this work include the examination of the fine-scale bio-physical mechanisms that link marine predators to tidal-mixing fronts and coastal tidal-topographic structures. Main findings indicate that offshore habitats around tidal-mixing fronts are used by both common dolphins and northern gannets for foraging. Individuals associated with patches of increased sub-surface primary productivity, which were generated via a bi-weekly cycle of episodic turbulent mixing and stratification following an adjustment in the spatial position of a front with the spring-neap cycle. Moreover, around fronts, the dives of gannets were likely to be short and of a V-shaped strategy (with little active swim phase), which likely reflects an increase in the accessibility and catchability of their prey. In a coastal estuarine system, bottlenose dolphins were shown to associate with predictable downwelling features generated during flood tidal flows that were thought to act as a foraging aid. Together, these findings highlight the fundamental role physical oceanographic processes play in the structuring of marine ecosystems by providing vulnerable marine predators with prosperous and reliable foraging resources that they can exploit. This work has implications for both future studies of marine predator foraging ecology and the management of anthropogenic activities in coastal and shelf-seas.
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Domènech, Guitart Anna. "Analysis of the functional roles of Mammary Serum Amyloid A3 protein." Doctoral thesis, Universitat Autònoma de Barcelona, 2013. http://hdl.handle.net/10803/125923.
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La Serum Amiloide A3 (M‐SAA3) mamària és una proteïna de fase aguda expressada
principalment a la glàndula mamària. Els nivells d’expressió de la M‐SAA3 varia en diferents
situacions fisiològiques, el que suggereix un rol important a nivell funcional. Per tal d’analitzar
les propietats de la proteïna, es van dur a terme quatre estudis. En el primer, la M‐SAA3 va ser
expressada de forma recombinant en un sistema bacterià. Aquest pas és important ja que ens
proporciona una font de proteïna, en casos en que la purificació de fonts naturals representa
clarament un coll d’ampolla. Es va obtenir la seqüència de dues isoformes, però només una va
ser expressada recombinantment. La principal diferència entre les dues formes era una deleció
en la regió del motiu SNARE, el que suggeria que aquest motiu pot estar implicat en una
activitat antibacteriana directe. A més, en el primer estudi es va analitzar la primera
funcionalitat. La M‐SAA3 activava la fagocitosi mediada per macròfags, incrementant el
nombre de macròfags actiu i la seva capacitat fagocítica. En el segon estudi es va analitzar
l’efecte protector a nivell gastrointestinal. La M‐SAA3 clarament reduïa la translocació de
bacteris enteropatògens en cèl∙lules CaCo‐2, una línia d’epiteli intestinal comercial. La M‐SAA3
també afectava la expressió de MUC3 i IL‐8, incrementant els seus nivells, el que connecta de
forma directa la proteïna amb la resposta immune innata. En el tercer estudi, es va
desenvolupar un model intestinal en boví a partir de cultius ex vivo de Plaques de Peyer.
Aquests cultius ex vivo ofereixen un ambient únic on coexisteixen diferents tipus cel∙lulars i
una aproximació més realista a la situació in vivo. En aquest context la infecció també va ser
disminuïda i la M‐SAA3 incrementava els nivells de IL‐8 i INFγ. Per contra, les mucines no es
van veure afectades, i la protecció va ser assolida per sobre‐expressió de Occludina i Claudina‐
2, proteïnes que formen les tight junctions, encarregades de segellar la barrera epitelial. A
més, es va demostrar que la M‐SAA3 activa cèl∙lules dendrítiques, incrementant l’expressió de
citoquines i marcadors de maduració, migració i presentació d’antigen. En el quart i últim
estudi, es va avaluar la possible aplicabilitat a nivell de la industria lletera. La M‐SAA3 va ser
infosa intra‐mamàriament durant el secat, un període on es deixa de munyir les vaques per tal
d’afavorir la regeneració cel∙lular i augmentar la seva productivitat. La M‐SAA3 va incrementar
paràmetres relacionats amb una activació de l’involució tals com les metaloproteinases. Els
nivells de proteïna i greix també eren augmentats i es va observar un augment numèric del
recompte de cèl∙lules somàtiques. També es va observar que la proteïna incrementava
l’expressió de IL‐8 i TNFα en cultius primaris de glàndula mamària, i també inhibia la infecció
bacteriana. Finalment, les cèl∙lules dendrítiques també eren activades en absència d’infecció<br>Mammary Serum Amyloid A3 (M‐SAA3) is an acute phase protein mainly expressed in the
mammary gland. The levels of the protein vary in different physiological situations, indicating
that may play an important functional role. In order to analyze the protein properties four
studies were performed. In the first study, the protein was recombinantly produced in a
bacterial expression system. This was important, as difficulty in protein purification from
natural sources is a clear bottleneck for functional studies. Two M‐SAA3 isoforms were
obtained, but only one succeeded in the recombinant expression. Interestingly, the main
difference was in a 3 amino acid deletion in the SNARE motif, which could be implicated in the
direct bacterial killing. Moreover, the first functional role was evaluated. M‐SAA3 clearly
enhanced macrophages phagocytosis, increasing both the number of active macrophages and
the phagocytic capacity. In the second study, the protective effect at a gastrointestinal level
was assessed. M‐SAA3 protein inhibited the translocation of enteropathogenic bacteria in
CaCo‐2 cells, a commercial intestinal epithelial cell line. In addition, M‐SAA3 protein increased
the expression of MUC3 and IL‐8, which directly connected the protein with the innate
immune response activation. In the third study, a bovine intestinal model was developed using
ex vivo Peyer’s Patches cultures. The ex vivo methodology offered a unique environment
where different cell types coexist, and indeed, represent a more similar approach to an in vivo
situation. In this context, the infection was also prevented, and a clear innate immune
response was activated. M‐SAA3 clearly activated the expression of IL‐8, INFγ but in this case,
mucins were not up‐regulated. The bacterial translocation was achieved by an increase in the
Occludin and Claudin‐2 expression, tight junction genes that directly participate in the sealing
of the epithelial barrier. Furthermore, the M‐SAA3 directly activated dendritic cells functions,
increasing their cytokine expression profile and cellular markers related to maturation,
migration and antigen presentation. In the fourth and last study, the potential applicability in
dairy industry was evaluated. M‐SAA3 was infused in the mammary gland at dry off, a period
of milking cessation which permits the mammary gland regeneration for an optimal production
in following lactations. M‐SAA3 increased parameters related to an increased involution of the
mammary gland, such as metalloproteinases. Also protein and fat were increased and a
numerical increase in the somatic cell count was observed. In addition, M‐SAA3 raised the IL‐8
and TNFα levels in primary mammary gland cultures, and inhibited bacterial infection. Finally,
dendritic cells were also activated by M‐SAA3 in absence of infection.
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Unger, Bianca [Verfasser]. "Marine debris in the North- and Baltic Seas : spatio-temporal distribution patterns and its occurrence in marine mammals / Bianca Unger." Hannover : Stiftung Tierärztliche Hochschule Hannover, 2019. http://d-nb.info/1190640481/34.
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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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Voß, Manja. "Revision of the Halitherium-species complex (Mammalia, Sirenia) from the late Eocene to early Miocene of Central Europe and North America." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2014. http://dx.doi.org/10.18452/16906.
Full textAbstract:
Die zu den Sirenia, oder Seekühen, zählende Gattung Halitherium ist mit Arten aus dem Obereozän bis Untermiozän bekannt. Obwohl Halitherium als monophyletisch angesehen wird, bestätigen alle bisherigen phylogenetischen Analysen die Paraphylie dieser Gruppe. Auch die auf Halitherium basierende nur fossil bekannte Unterfamilie Halitheriinae ist paraphyletisch und umfasst wiederum fast ausnahmslos paraphyletische Gattungen. Der Fokus liegt auf der Typusart H. schinzii. Deren Holotyp, ein Premolar, wird als undiagnostisch definiert und infolgedessen H. schinzii als nomen dubium eingestuft. Die Neubeschreibung sämtlicher dieser Art zugeordneter Skelettreste liefert neue morphologische Daten. So kann die Hypothese von zwei sympatrisch vorkommenden Morphospezies im Unteroligozän Zentraleuropas auf Basis mehrerer unterscheidender Merkmale gestützt werden. Für die Verwandtschaftsanalyse der „Halitherium“ traditionell zugeordneten Arten und die Ermittlung ihrer phylogenetischen Stellung innerhalb der Ordnung Sirenia finden strenge kladistische Prinzipien Berücksichtigung. Eine revidierte, ergänzte und erweiterte Merkmalsmatrix stellt dabei den bisher größten morphologischen Datensatz über Sirenia dar. Die phylogenetischen Analysen zeigen, dass die „Halitherium“ Arten keine monophyletische Gruppe bilden. Im Zuge dieser systematisch-taxonomischen Revision werden die „Halitheriinae“ eingezogen und vier neue Gattungen aufgestellt. Des Weiteren wird eine neue Klassifikation der Sirenia vorgeschlagen, in der eine konsequente Unterscheidung zwischen einer paraphyletischen Stammgruppe und einer monophyletischen Kronengruppe Anwendung findet. Diese Studie liefert neue Daten über die Diversität und Biogeographie von Sirenen. Die herausragendsten Ergebnisse sind zum einen die Revision einer der zweifelhaftesten Sirenia Gruppen, die „Halitheriinae“. Zum anderen wird für den Ursprung der Kronengruppensirenen ein eher unteroligozäner statt eozäner Zeitpunkt postuliert.<br>The genus Halitherium includes a number of fossil sirenian species, or sea cows, ranging from the late Eocene to early Miocene. Although Halitherium is assumed to be monophyletic, all previous phylogenetic analyses reveal this group to be paraphyletic. As such, the exclusively extinct subfamily Halitheriinae based on Halitherium is paraphyletic comprising mainly genera that are invariably paraphyletic as well. The focus lies on the type species H. schinzii and the morphological basis for its establishment. The holotype, a single premolar, is considered non-diagnostic, which resulted in the recognition of this taxon name as a nomen dubium. Abundant skeletal material originally assigned to “H. schinzii” is re-described providing new data on the morphology of this sirenian. In this process, the hypothesis of two sympatric morphospecies in the lower Oligocene of Central Europe is corroborated by a suite of distinguishing characters. For the analysis of the interrelationships of the species traditionally assigned to “Halitherium”, and the identification of their phylogenetic position within the order Sirenia, robust cladistic principles are applied. A revised, supplemented and extended data matrix represents the hitherto largest data set on Sirenia based on morphological characters. The phylogenetic analyses show that the “Halitherium” species do not form a monophyletic group. In the course of this systematic and taxonomic revision the “Halitheriinae” are refuted and four new genera are established. Furthermore, a new systematic framework is introduced for Sirenia primarily distinguishing between a paraphyletic stem group and a monophyletic crown group. This study provides new data on the past sirenian diversity and biogeography. The most important results are that one of the most disputed sirenian groups, the “Halitheriinae”, is revised, and that the divergence time of crown group sirenians is estimated as early Oligocene rather than Eocene.
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Menezes, Lorena Tannús. "Morfologia do tubo digestório do tamanduá bandeira Myrmecophaga tridactyla (Pilosa: Myrmecophagidae)." Universidade Federal de Uberlândia, 2013. https://repositorio.ufu.br/handle/123456789/13057.
Full textAbstract:
This study described morphological aspects of the digestive
tract of the giant anteater (Myrmecophaga tridactyla), five specimens were used,
belonging to the collection of the Laboratório de Ensino e Pesquisa em Animais
Silvestres in UFU, were processed by usual methods of macroscopic anatomical,
histological and scanning electron microscope (SEM) analysis. The esophagus is a
narrow tube that goes straight in the thoracic cavity. The stomach has the shape of
the letter J, have the cardiac, fundic, corpus and pyloric regions. The small intestine
is long, has a duodenum, jejunum and ileum. The large intestine is short, consisting
of ascending colon, transverse colon, descending colon, rectum and anus. The lining
epithelial of the esophagus is stratified squamous, non-glandular; and scanning
electron microscopic examination of the esophagus is smooth and pleated. Stomach
is simple prismatic relatively low, with shallow crypts; and rough surface. In the small
intestine is simple prismatic, the duodenum has goblet cells, a huge amount of
Paneth cells, the jejunum has an increase of Paneth cells, the ileum has a few
Paneth cells and an increase of goblet cells; and villous surface; the large intestine is
simple prismatic, an increase goblet cells; and smooth surface with openings of
intestinal crypts.<br>Este estudo descreveu aspectos morfológicos do tubo digestório
de Myrmecophaga tridactyla, foram utilizados cinco espécimes, pertencentes ao
acervo do Laboratório de Ensino e Pesquisa em Animais Silvestres da UFU e foram
processados conforme métodos rotineiros de análise anatômica macroscópica,
histologia e microscopia eletrônica de varredura. O esôfago é um tubo estreito que
percorre a cavidade torácica sem angulações. O estômago possui o formato da letra
J, com regiões cárdica, fúndica, do corpo e pilórica. O intestino delgado é longo,
possui um duodeno, jejuno e íleo. O intestino grosso é curto, formado por colón
ascendente, cólon transverso, cólon descendente, reto e ânus. O epitélio de
revestimento do esôfago é estratificado pavimentoso, aglandular; e a análise
microscópica eletrônica de varredura do esôfago é superfície lisa com pregas. No
estômago é simples prismático mucíparo, relativamente baixo, com criptas rasas; e
superfície rugosa. No intestino delgado é simples prismático; no duodeno tem
células caliciformes e uma enorme quantidade de células de Paneth, no jejuno
aumento das células de Paneth, no íleo poucas células de Paneth e aumento das
células caliciformes; e superfície com vilos; no intestino grosso é simples prismático,
aumento da quantidade das células caliciformes; e superfície lisa com aberturas das
criptas intestinais.<br>Mestre em Ciências Veterinárias
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Santana, Aline Barros 1979. "Soro Amilóide A (SAA) e Adiponectina = caracterização no câncer de mama na pós-menopausa e relação com obesidade." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/309735.
Full textAbstract:
Orientador: Sílvia de Barros Mazon<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas<br>Made available in DSpace on 2018-08-20T03:36:20Z (GMT). No. of bitstreams: 1
Santana_AlineBarros_M.pdf: 715563 bytes, checksum: 9bb4034477639e280abce35c25dc01b0 (MD5)
Previous issue date: 2012<br>Resumo: A obesidade tem aumentado consideravelmente nas últimas cinco décadas em todo mundo. A Organização Mundial de Saúde estima que pessoas com sobrepeso ultrapassem a casa do bilhão e que cerca de 300 milhões sejam obesas. No contexto da inflamação crônica presente na obesidade, as adipocinas SAA e adiponectina, que possuem funções antagônicas, têm demonstrado notável destaque na literatura e ambas também têm sido associadas com o desenvolvimento e prognóstico do câncer de mama. No presente estudo foi investigada a associação entre obesidade, SAA e adiponectina em portadoras de câncer de mama na fase pós-menopausa e suas relações com as características clínico-patológicas dos tumores. Para esta investigação as pacientes participantes do estudo foram divididas em dois grupos: o primeiro grupo foi composto por mulheres com sobrepeso/obesidade e presença de gordura abdominal e o segundo grupo por mulheres não-obesas, com ausência de gordura abdominal. Os dados encontrados demonstraram que as concentrações séricas de SAA foram maiores em pacientes com sobrepeso/obesidade e que essa elevação foi dependente da obesidade, aqui caracterizada tanto pelo índice de massa corpórea (IMC) quanto pela circunferência abdominal (CA). Concentrações mais elevadas de SAA foram também observadas em portadoras de tumores com ausência de expressão de receptores de estrógeno (RE-), do que naquelas com tumores RE+. Quanto às concentrações de adiponectina, não foram verificadas associações com o IMC ou CA. Também não foram demonstradas associações entre as concentrações séricas de SAA ou adiponectina com o estadiamento clínico-patológico dos tumores. Os dois grupos apresentaram freqüências semelhantes em relação aos diferentes graus de estadiamento clínico-patológico (ECP) e expressão dos receptores hormonais RE e RP. Todavia, observou-se maior freqüência do receptor do fator de crescimento epidérmico tipo 2 humano (HER2+) entre os tumores das pacientes não-obesas, sugerindo mecanismo de expressão independente da obesidade. Em relação à freqüência de parâmetros bioquímicos alterados, o grupo de não-obesas apresentou maior freqüência de colesterol total (Col-T) acima do valor de referência e o grupo com sobrepeso/obesidade mostrou tendência de maior freqüência de concentrações alteradas de glicose (Gli). A avaliação da relação das adipocinas com os parâmetros bioquímicos revelou que a SAA mostrou correlação positiva com a Gli e que a adiponectina correlacionou-se inversamente com triglicerídeos (TG) e Gli e diretamente com a lipoproteína de alta densidade (HDL-Col). Nossos resultados permitem aventar a hipótese de uma possível participação da SAA, no contexto da obesidade, no desenvolvimento do câncer de mama. O acompanhamento desta população, para avaliação da sobrevida total e sobrevida livre de doença poderá contribuir para a elucidação da importância biológica e/ou clínica da SAA e da adiponectina no câncer de mama. Resultados futuros poderão embasar a adoção do tratamento da obesidade como medida preventiva, para proporcionar um melhor prognóstico para as portadoras de câncer de mama com sobrepeso/obesidade<br>Abstract: Obesity has increased considerably in the last five decades worldwide. According to the World Health Organization (WHO), it is estimated that, globally, there are more than 1 billion overweight adults, and that there are at least 300 million clinically obese. In the context of chronic inflammation present in obesity, SAA and adiponectin are adipokines which have antagonistic functions and both have been associated with the development and prognosis of breast cancer. In the present study we investigated the association among obesity, SAA and adiponectin in women bearing breast cancer in postmenopausal and their relationships with clinical-pathological characteristics of the tumors. For this investigation the patients were grouped as follows: one group by overweight/obese women (presence of abdominal fat) and the second was composed of non-obese women (no abdominal fat). The findings demonstrated that serum SAA concentrations were higher in patients with overweight/obese and this condition was dependent on obesity, here characterized by both the body mass index (BMI) and waist circumference (WC). Concentrations of SAA were also higher in women bearing ER- breast cancer than in ER+ ones. Conversely, adiponectin did not show association with BMI or with WC. There were no associations between serum concentrations of SAA or adiponectin and the clinical-pathological staging of the tumors. SAA showed direct correlation with glucose and adiponectin correlated inversely with triglycerides and glucose e directly with high-density lipoprotein (HDL-Chol). The nonobese group showed a more elevated frequency of abnormal values of total cholesterol, and overweight/obesity group showed a trend of higher frequency of altered glucose concentrations. The expression of human epidermal growth factor receptor 2 (HER2+) was higher among non-obese breast cancer, suggesting an obesity-independent expression mechanism. Our results allow the hypothesis of a possible role for SAA in the development and prognosis of breast cancer in the context of obesity. The follow up of this population to assess overall and disease-free survival may contribute to the elucidation of SAA and adiponectin biological and/or clinical significance in breast cancer. This may support the adoption of treating obesity as a preventive action against the onset as well as to provide better prognosis for overweight/obesity breast cancer patients<br>Mestrado<br>Ciencias Biomedicas<br>Mestre em Ciências Médicas
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Donaldson, Laura Patricia Constance. "The distribution of fatty acids and presence of environmental contaminants in the blubber of the New Zealand sea lion (Phocarctos hookeri) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/887.
Full textAbstract:
The conservation of marine mammals relies on the knowledge of species ecology in order to assess the impacts of anthropogenic activites and make appropriate species management decisions. Blubber biopsies are a relatively non-invasive sampling protocol to provide ecological information; two particular uses are for dietary analysis via fatty acid signature analysis (FASA) and investigating the uptake of organochlorine (OC) and polychlorinated biphenyl (PCB) environmental contaminants. Blubber composition and structure may vary according to body site and depth due to its dynamic functioning. This may result in the vertical stratification and heterogenous distribution of blubber FAs, OCs and PCBs between body sites, giving variable interpretations of diet and contaminant levels depending on biopsy sample site and depth. The aim of this thesis is to determine the FA distribution of blubber from two body sample sites (dorsal pelvic and ventral thoracic) currently used for FASA of the New Zealand sea lion, Phocarctos hookeri (NZSL) and to determine the level of OCs and PCBs in the blubber of healthy NZSLs for comparison to diseased NZSLs recorded in the 1997/98 epidemic. Blubber samples were collected from 29 by-caught NZSLs incidentally captured by the squid fishery around the Auckland Islands (50º42’S, 166º5’E) during the years 2005 to 2007 (not all NZSLs were able to be analysed for each chapter). Full blubber cores from both sample sites were collected from 18 NZSLs. Both sites showed a relative homogeneity of FA profiles, indicating the similar deposition and mobilisation of FAs at the two sample sites. To determine if FA stratification occurred, full blubber cores from both sample sites of 20 NZSLs were divided into inner and outer halves. Both sites displayed the same pattern of vertical stratification or biochemical layering of FAs between the two divisions, indicating that stratification of FAs occurs in the blubber of the NZSL. A range of OCs and PCBs were then determined in full thoracic blubber cores of seven NZSLs. The levels were higher than those previously recorded in NZSLs affected by disease during a 1997/98 epidemic. The SPCB in NZSLs was 0.034-0.192 mg/kg lipids, below the suggested threshold of 17 mg/kg for adverse health affects in marine mammals. From the results of this study I can support current blubber biopsy sampling techniques for FASA in NZSL. Obtaining full blubber cores from either the thoracic or pelvic sample site will give a comparable interpretation of diet. The low levels of blubber OCs and PCBs suggest a minor role of contaminants acting as a possible causative agent toward disease outbreaks in the NZSL. This research provides important information for developing correct and consistent blubber sampling techniques for NZSL and other pinniped species. This will ensure more accurate interpretations of ecological information obtained from blubber biopsies and therefore improved species management and conservation decisions that may be based on such research.
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Page, Brad, and page bradley@saugov sa gov au. "Niche partitioning among fur seals." La Trobe University. Zoology Department, School of Life Sciences, 2005. http://www.lib.latrobe.edu.au./thesis/public/adt-LTU20060622.153716.
Full textAbstract:
At Cape Gantheaume, Kangaroo Island (South Australia), adult male, lactating female
and juvenile New Zealand (NZ) and Australian fur seals regularly return to the same
colony, creating the potential for intra- and inter-specific foraging competition in nearby
waters. I hypothesised that these demographic groups would exhibit distinct foraging
strategies, which reduce competition and facilitate their coexistence. I analysed the diet
of adult male, adult female and juvenile NZ fur seals and adult male Australian fur seals
and studied the diving behaviour of adult male and lactating female NZ fur seals and the
at-sea movements of juvenile, adult male and lactating female NZ fur seals. Female diet
reflected that of a generalist predator, influenced by prey availability and their
dependant pups� fasting abilities. In contrast, adult male NZ and Australian fur seals
used larger and more energy-rich prey, most likely because they could more efficiently
access and handle such prey. Juvenile fur seals primarily utilised small lantern fish,
which occur south of the shelf break, in pelagic waters. Juveniles undertook the longest
foraging trips and adult males conducted more lengthy trips than lactating females,
which perform relatively brief trips in order to regularly nurse their pups. Unlike lactating
females, some adult males appeared to rest underwater by performing dives that were
characterised by a period of passive drifting through the water column. The large body
sizes of adult males and lactating females facilitated the use of both benthic and pelagic
habitats, but adult males dived deeper and for longer than lactating females, facilitating
vertical separation of their foraging habitats. Spatial overlap in foraging habitats among
the age/sex groups was minimal, because lactating females typically utilised continental
shelf waters and males used deeper water over the shelf break, beyond female foraging
grounds. Furthermore, juveniles used pelagic waters, up to 1000 km south of the
regions used by lactating females and adult males. The age and sex groups in this
study employed dramatically different strategies to maximise their survival and
reproductive success. Their prey and foraging habitats are likely to be shaped by body
size differences, which determine their different physiological constraints and metabolic
requirements. I suggest that these physiological constraints and the lactation
constraints on females are the primary factors that reduce competition, thereby
facilitating niche partitioning.
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Legrand-Defretin, Véronique. "Dynamique du recyclage enterohepatique des acides biliaires totaux et individuels chez le porc." Paris 7, 1988. http://www.theses.fr/1988PA077101.
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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.
Full textAbstract:
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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Hills, Crystal Margie. "Wees Gonna Tell It Like We Know It Tuh Be: Coded Language in the Works of Julia Peterkin and Gloria Naylor." unrestricted, 2008. http://etd.gsu.edu/theses/available/etd-08152008-071048/.
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Thesis (M.A.)--Georgia State University, 2008.<br>Title from file title page. Carol Marsh-Lockett , committee chair; Mary Zeigler, Kameelah Martin Samuel, committee members. Electronic text (99 p.) : digital, PDF file. Description based on contents viewed Nov. 19, 2008. Includes bibliographical references (p. 96-99).
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Siegelman, Lia. "Ageostrophic dynamics in the ocean interior A correction for the thermal mass–induced errors of CTD tags mounted on marine mammals, in the Journal of Atmospheric and Oceanic Technology 35 (6), June 2018 Submesoscale ocean fronts act as biological hotspot for southern elephant seal, in Scientific Reports 9, 2019 Ocean‐scale interactions from space, in Earth and Space Science 6(5), May 2019 Correction and accuracy of high- and low-resolution CTD data from animal-borne instruments, in the Journal of Atmospheric and Oceanic Technology 36 (5), May 2019 Diagnosing ocean‐wave‐turbulence interactions from space, in Geophysical Research Letters 46(15), August 2019 Sub‐mesoscale fronts modify elephant seals foraging behavior, in Limnology and Oceanography Letters, 4(6), December 2019." Thesis, Brest, 2019. http://www.theses.fr/2019BRES0094.
Full textAbstract:
L'océan est le plus grand réservoir d'énergie solaire de notre planète. La quantité de chaleur qu'il est capable de stocker est modulée par sa circulation complexe, opérant sur une vaste gamme d’échelles allant du centimètre à la dizaine de milliers de kilomètres. Cette thèse s'intéresse à deux types de processus océaniques: les tourbillons de mésoéchelle, d'une taille de 100 à 300 km, et les fronts de sous-mésoéchelle, d'une taille inférieure à 50 km. L'idée communément admise est que les mouvements agéostrophiques de sous-mésoéchelle sont principalement confinés à la couche de mélange océanique de surface et sont faibles dans l'océan intérieur. Cette vision classique de la dynamique océanique repose sur l'hypothèse que l'océan intérieur est en équilibre quasi-géostrophique, empêchant la formation de forts gradients de densité en profondeur. Cette thèse remet en question ce paradigme en se basant sur des observations CTD in situ à haute résolution collectées par des éléphants de mer instrumentés, des images satellite d’élévation de la surface de l’océan, et des sorties de modèle à haute résolution dans le Courant Circumpolaire Antarctique.Les résultats indiquent que les mouvements agéostrophiques sont (i) générés par le champ tourbillonnaire de mésoéchelle via des processus defrontogenèse, et (ii) ne sont pas limités à la couche de mélange de surface ; bien au contraire, ils pénètrent dans l'océan intérieur jusqu'à 1000 m deprofondeur. Ces fronts agéostrophiques de sous-mésoéchelle sont associés à d'importants flux de chaleur dirigés de l'intérieur de l'océan vers la surface, d'une amplitude comparable aux flux air-mer.Cet effet peut potentiellement altérer la capacité de stockage de chaleur de l'océan et devrait être le plus fort dans les zones tourbillonnaires telles que le Courant Circumpolaire Antarctique, le Kuroshio et le Gulf Stream, les trois courants clefs du système climatique. Il apparaît ainsi que les fronts agéostrophiques de sous-mésoéchelle représentent une voie importante, mais encore largement méconnue, pour le transport de chaleur, de nutriments et de gaz entre l'intérieur et la surface de l'océan, avec des répercussions potentiellement majeures pour les systèmes biogéochimique et climatique<br>The ocean is the largest solar energy collector on Earth. The amount of heat it can store is modulated by its complex circulation, which spans a broad range of spatial scales, from centimeters to thousands of kilometers. This dissertation investigates two types of physical processes: mesoscale eddies (100-300 km size) and submesoscale fronts (£ 50 km size). To date, ageostrophic submesoscale motions are thought to be mainly trapped within the ocean surface mixed layer, and to be weak in the ocean interior. This is because, in the classical paradigm, motions below the mixed layer are broadly assumed to be in quasigeostrophic balance, preventing the formation of strong buoyancy gradients at depth. This dissertation introduces a paradigm shift; based on a combination of high-resolution in situ CTD data collected by instrumented elephant seals, satellite observations of sea surface height, and high-resolution model outputs in the Antarctic Circumpolar Current, we show that ageostrophic motions (i) are generated by the backgound mesoscale eddy field via frontogenesis processes, and (ii) are not solely confined to the ocean surface mixed layer but, rather, can extend in the ocean interior down to depths of 1 000 m. Deepreaching ageostrophic fronts are shown to drive an anomalous upward heat transport from the ocean interior back to the surface that is larger than other contributions to vertical heat transport and of comparable magnitude to air-sea fluxes. This effect can potentially alter oceanic heat uptake and will be strongest in eddy-rich regions such as the Antarctic Circumpolar Current, the Kuroshio Extension, and the Gulf Stream, all of which are key players in the climate system. As such, ageostrophic fronts at submesoscale provide an important, yet unexplored, pathway for the transport of heat, chemical and biological tracers, between the ocean interior and the surface, with potential major implications for the biogeochemical and climate systems
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Milanez, Adriano Márcio de Melo. "Estudo prospectivo e randomizado da revascularização do miocárdio minimamente invasiva com dissecção da artéria torácica interna esquerda por videotoracoscopia robótica." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/5/5156/tde-11012012-144551/.
Full textAbstract:
Objetivos: O objetivo desse estudo foi comparar a perviedade da artéria torácica interna esquerda (ATIE) dissecada por videotoracoscopia robótica para revascularização minimamente invasiva do ramo interventricular anterior (RIA) com a revascularização do miocárdio convencional. Métodos: De 2007 a 2010, 36 pacientes foram randomizados para revascularização do miocárdio minimamente invasiva (RMMI) ou revascularização do miocárdio convencional (RMC). Pacientes randomizados para o grupo RMMI foram submetidos à dissecção da ATIE por videotoracoscopia auxiliada pelo braço robótico AESOP seguida de uma minitoracotomia anterior esquerda no 4º espaço intercostal para anastomose com o RIA. Pacientes randomizados para o grupo RMC foram submetidos a revascularização do miocárdio convencional com esternotomia mediana completa, dissecção aberta da ATIE e anastomose ao RIA. Fluxometria por tempo de trânsito (FTT) foi utilizada para avaliação da perviedade da ATIE imediata. Após 24 meses uma tomografia multislice foi utilizada para avaliar a perviedade a médio prazo da ATIE. Resultados: O tempo médio de dissecção da ATIE no grupo RMMI foi de 50,1 ± 11,2 vs. 22,7 ± 3,3 min no grupo RMC. Não houve diferença significativa no fluxo médio da ATIE para o RIA entre os grupos estudados (46,17 ± 20,11 vs. 48,61 ± 23,42 mL/min, p=0,86) respectivamente. Não houve diferença significante na incidência de infecção de ferida profunda (0 vs. 2, p=0,48) e necessidade de reoperação por sangramento (0 vs. 1, p=1,00) nos grupos RMMI e RMC respectivamente. A angiotomografia mostrou perviedade da ATIE em 100% dos pacientes do grupo RMMI vs. 94,1% no grupo RMC (p=1,00). Não houve mortalidade nos grupos estudados. Conclusão: A revascularização do miocárdio minimamente invasiva do ramo interventricular anterior com dissecção da artéria torácica interna esquerda por videotoracoscopia robótica foi segura e factível. A perviedade da artéria torácica interna esquerda imediata e a médio prazo foi similar entre ambas as técnicas<br>Objective: The aim of this study was to compare the patency of left internal mammary artery (LIMA) robotically harvested for left anterior descendent (LAD) artery minimally invasive bypass with conventional LIMA to LAD off-pump bypass. Method: From 2007 to 2010, 36 patients were randomized to either LIMA robotically harvested to LAD artery minimally invasive bypass or standard LIMA to LAD off-pump bypass. Patients assigned to robotic group underwent robotic endoscopic harvesting of LIMA with the AESOP system followed by a small left thoracotomy in the 4th intercostal space for off-pump LAD bypass. Patients assigned to standard group underwent full median sternotomy, open LIMA harvesting followed by off-pump LAD bypass. Transit time flow measurement was used for intraoperative evaluation of LIMA to LAD patency. After a mean 24-month follow-up, Multislice Computed Tomography was used to evaluate LIMA to LAD midterm patency. Results: The mean LIMA harvesting time in robotic group was 50.1 ± 11.2 min vs. 22.7 ± 3.3 min in conventional group. There was no significant difference in intraoperative LIMA to LAD flow between robotic and conventional groups (46.17 ± 20.11 mL/min vs. 48.61 ± 23.42 mL/min, p=0.86). There were no significant differences in incidence of wound infection (0 vs. 2, p=0,48) and reoperation for bleeding (0 vs. 1, p=1.00) between robotic and conventional groups respectively. In robotic group, Multislice CT revealed patent LIMA graft in 100% patients vs. 94.1% patients in conventional group (p=1.00). There was no mortality in the study group. Conclusions: Minimally invasive LAD bypass using LIMA graft robotically harvested was safe and feasible. Early and mid-term LIMA patency was similar between both techniques
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Bjorkland, Rhema Hyacinth. "An Assessment of Sea Turtle, Marine Mammal and Seabird Bycatch in the Wider Caribbean Region." Diss., 2011. http://hdl.handle.net/10161/5632.
Full textAbstract:
<p>Sea turtles, marine mammals and sea birds are vulnerable to higher mortality rates as a direct function of incidental capture (bycatch) in marine fisheries. Their migratory behavior exposes them to multiple fishing gear types and fishing practices and efforts to understand the rates of interaction between these taxa and fishing necessarily entails analysis of data over large spatial areas (ocean-basin) and multiple types of fishing activities. The acquisition the requisite data, however, requires considerable resources and many regions in the world are data-poor with respect to bycatch, including the Wider Caribbean Region (WCR) in the west central Atlantic Ocean basin. This dissertation presents the results of multiple strategies used to assess sea turtle, marine mammal and seabird bycatch in the WCR, with a particular focus on sea turtle bycatch. The research incorporated a synthetic review of the literature, expert consultation, statistical techniques, and geospatial analyses to assess the bycatch seascape for the region. I conclude that sea turtle bycatch in the WRC is significantly linked to turtle rookeries, especially those on the continental land mass and in the southern section of the Caribbean basin, in large part because of the near shore artisanal nature of the fisheries and the importance of these habitats for foraging and reproduction. The limited information on marine mammal bycatch does not permit robust inferences, but it clearly identifies threats to at least one vulnerable marine mammal species, the tucuxi (Sotalia fluviatilis). Information on seabird bycatch was even more limited; the most vulnerable seabird populations occur in the higher latitudes (temperate zones) while the seabird populations in the WCR face significant threats from habitat loss and over-exploitation. This dissertation proposes specific recommendations for improving and advancing the information base for a regional, ecosystem-level management and mitigation of bycatch.</p><br>Dissertation
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Szaniszlo, Wendy Renee. "California sea lion (Zalophus californianus) and Steller sea lion (Eumetopias jubatus) interactions with vessels in Pacific Rim National Park Reserve : implications for marine mammal viewing management." 2005. http://hdl.handle.net/1828/777.
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Fisher, Jason Thomas. "Cross-scale habitat selection by terrestrial and marine mammals." Thesis, 2010. http://hdl.handle.net/1828/3649.
Full textAbstract:
Ecology has been devoted to defining the content of a species’ environment. Defining the extent, or size, of a species’ environment is also pivotal to elucidating species-habitat relationships. More than a home range, this extent integrates an individual’s lifetime experiences with resources, competition, and predators. I theorised that a species’ habitat extent is identifiable from its characteristic spatial scale of habitat selection, which in turn is predicted by body size. I reviewed scale-dependent mammalian habitat selection studies and found that a characteristic scale was typically not identified, but identifiable. Of several ecological predictors tested, only body mass was a significant predictor of the relative size of a species’ characteristic habitat selection scale.
Tests of existing data are confounded by differing approaches, so I empirically tested the scale-body mass hypothesis using a standardised survey of 12 sympatric terrestrial mammal species from the Canadian Rocky Mountains. For each species, support for habitat models varied across 20 scales tested. For six species, I found a characteristic selection scale, which was best predicted by species body mass in a quadratic relationship. Occurrence of large and small species was explained by habitat measured at large scales, whereas medium-
sized species were explained by habitat measured at small scales. The relationship between body size and habitat selection scale is congruent with the textural-discontinuity hypothesis, and implies species’ evolutionary adaptation to landscape heterogeneity as the driver of scale-dependent habitat selection. I applied this principle to examine wolverine habitat selection, and found that anthropogenic fragmentation of the landscape influences that species’ occurrence in space at large spatial scales.
Finally, I contended that the prevailing paradigm equating habitats to resources omits interspecific interactions that are key predictors of a species’ occurrences. I examined habitat selection of martens and fishers in terrestrial environments, and sea otters in marine coastal environments, and tested whether the presence of heterospecifics could explain spatial occurrence beyond landscape structure and resources. In both cases, the presence of heterospecifics explained species occurrence beyond simple resource selection. Interspecific interactions are key drivers of a species’ distribution in space; this is the spatial expression of the concepts of fundamental and realized niches. Body size interacts with landscape structure to determine the scale of a species’ response to its environment, and within this habitat extent, interspecific interactions affect the species’ pattern of occurrence and distribution.<br>Graduate
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Higdon, Jeffrey Wayde. "Biogeography and conservation of the pinnipeds (Carnivora: Mammalia)." 2011. http://hdl.handle.net/1993/4346.
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This thesis examines the biogeography of world pinnipeds, a unique group of marine mammals that have adapted to marine foraging while maintaining terrestrial (land or ice) habitat links. Comparative analyses of species range sizes controlled for phylogenetic relationships using a multi-gene supertree with divergence dates estimated using fossil calibrations. Adaptations to aquatic mating and especially sea ice parturition have influenced range size distribution, and ranges are larger than those of terrestrially mating and/or pupping species. Small range size is endangering for many taxa, and most at risk pinnipeds are terrestrial species with small ranges. Ancestral state reconstructions suggest that pinnipeds had a long association with sea ice, an adaptation that would have allowed early seals to expand into novel habitats and increase their distribution. Range sizes exhibit a strong Rapoport effect (positive relationship between range size and latitude) at the global scale, even after controlling for phylogeny and body size allometry. A latitudinal gradient in species diversity cannot explain the Rapoport effect for global pinniped ranges, as diversity is highest at mid-latitudes in both hemispheres. These regions are characterized by marginal ice zones and variable climates, supporting a mix of pagophilic and temperate species. The climatic variability hypothesis also did not explain the Rapoport effect. Variability is bimodal, and annual sea surface temperature (SST) variability does explain diversity patterns. Range size has a significant negative relationship with annual mean SST, and the largest ranges are found in areas with low mean SST. Temperature responses are possibly related to thermoregulation, sea ice availability, and ecological relationships with other large marine predators. These results agree with other studies and suggest that ocean temperature, and not productivity, drives marine species richness patterns. Future research needs include studies of physiological tolerances, interactions with sharks as predators and competitors, and the role of climate and sea ice in speciation and evolution. A better understanding of distribution and diversity patterns, and the role of the environment in shaping these patterns, will improve conservation efforts, and studies on the role of SST and sea ice are particularly important given current warming trends and declines in ice extent.
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Noel, Marie. "Bioaccumulative contaminants in marine mammals: uptake and effects." Thesis, 2013. http://hdl.handle.net/1828/4519.
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This thesis provides insights into the transport and fate of contaminants of concern (polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and mercury (Hg)), as well as results on the impacts of these compounds on marine mammal health.
Atmospheric transport is known to be a significant pathway for the delivery of contaminants to remote food webs. Air and rain samples were collected from one remote site on the west coast of Vancouver Island, British Columbia (BC), Canada, and from one near-urban site in the Strait of Georgia, BC. While global atmospheric dispersion was observed for the legacy PCBs, 40% of PBDEs detected in BC air appeared to be originating from trans-Pacific transport. It was estimated that 3kg of PCBs and 17kg of PBDEs were deposited every year in the Strait of Georgia.
Once deposited, PCBs, PBDEs and Hg biomagnify up the food chain. Harbour seals are non-migratory and can be used to provide signals of local contaminant sources. They have been extensively used as indicators of PCB and PBDE food web contamination in the BC coastal environment. The collection of over 200 harbour seal fur samples from various locations around Vancouver Island, BC and Puget Sound, WA, USA helped us pinpoint three sites where Hg levels were significantly higher than our reference site, Bella Bella (Queen Charlotte Strait, Port Renfrew and central Puget Sound). A combination of anthropogenic sources and marine food web processes appeared to influence the delivery of methylmercury (MeHg) to the top of this coastal marine food chain. Our results also suggested that these Hg levels (1.6-46.9 µg/g) could be a concern for the health of these harbour seals.
Genomic techniques were used to generate insights into the implications of contaminant exposure on the health of marine mammals inhabiting industrialized regions (harbour seals from the Northeastern Pacific and Northwestern Atlantic) and remote, supposedly pristine, environment (Arctic beluga whales). In harbour seal blubber, there were positive correlations between the mRNA levels of several genes, including estrogen receptor alpha (Esr1), thyroid hormone receptor alpha (Thra), and glucocorticoid receptor (Nr3c1), and PCB levels. In beluga blubber, aryl hydrocarbon receptor (Ahr) and cytochrome P450 (Cyp1a1) mRNA levels increased with PCBs, consistent with their role in toxicity.While PCB-related toxic responses were observed in both species, additional factors appeared to be affecting the expression of important genes in beluga. Our results suggested that a shift in beluga diet during periods of low sea ice extent, as evidenced by changes in δ13C isotope ratios, had a significant impact on mRNA levels coding for genes involved in growth, metabolism and development.
The use of a dual study design to evaluate the long range versus local sources of contaminants highlighted the importance of trans-Pacific transport in the delivery of PBDEs to coastal BC and the occurrence of local Hg sources in this marine environment. However, consistent with previous studies, our results suggested that PCBs remain the top contaminant of concern for marine mammal health. We also raised questions about the potential exacerbation of toxic risks due to PCBs as a consequence of climate changes currently underway in the Arctic.<br>Graduate<br>0768<br>0383<br>marie.t.noel@gmail.com
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Fraser, Molly. "Whale and small vessel interactions: exploring regulatory compliance and management implications in the Salish Sea." Thesis, 2020. http://hdl.handle.net/1828/12063.
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Compliance is a key feature for the management of non-consumptive wildlife viewing, as it can link management measures to performance and aid in developing recommendations that promote sustainable practices. Whale watching is a prominent wildlife viewing industry that is steadily rising in demand around the world. Managing vessel-cetacean encounters and operator behaviour (both commercial and recreational) is key to limiting impacts on cetaceans, yet the scale of regulatory compliance is often poor or unknown. Although efforts exist to regulate whale watching, challenges arise for the assessment of compliance in marine environments, as they are inherently spatially vast, lack physical boundaries, and can involve mobile stressors (i.e. vessels) and species. Chapter 1 reviews the shift in paradigms from consumptive to non-consumptive activities and highlights challenges for those tasked with managing the growing wildlife tourism industry, and in particular, whale watching. After reviewing a suite of measures prevalent around the world, this chapter then focuses on the Salish Sea’s approach to managing whale watching. This area epitomizes a major whale watching hub and displays complex, multi-jurisdictional and constantly evolving measures. Due to a lack of knowledge in this region, Chapter 2 shifts from theory to practice and assesses regulatory compliance with marine mammal distance regulations from 2018 to 2019 in the Salish Sea. Although compliance was nearly 80%, key drivers including vessel and species type were found to significantly influence non-compliance. Recreational vessels were non-compliant 41.9% of the time and 74.2% of non-compliant encounters occurred around killer whales across both years. The findings of the study demonstrate that case-specific investigation of compliance is necessary as each region is unique in its approach to management. Lastly, recommendations are proposed that can benefit marine managers and policymakers to enhance the performance of measures and subsequently minimize risk to cetaceans.<br>Graduate
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Coombs, Andrea Pauline. "Marine mammals and human health in the Eastern Bering Sea : using an ecosystem-based food web model to track PCBs." Thesis, 2004. http://hdl.handle.net/2429/15476.
Full textAbstract:
The comprehensive changes that have occurred in the Bering Sea over the last 30 years
have prompted a wide range of studies to better understand the ecosystem as a whole.
One set of studies has used the Ecopath with Ecosim (EwE) modelling software to
synthesise existing biological data and gain insight into how the ecosystem was before
and after the system-wide changes. This modelling framework provides a means for
tracing contaminants through the ecosystem, and evaluating the role that persistent
organic pollutants (POPs) may have played in the changing dynamics of the eastern
Bering Sea. Using the EwE software, the likely pathways of PCB flow within the eastern
Bering Sea were identified and health implications of contaminant exposure for Steller
sea lions, other species of marine mammals, and humans were evaluated. The base EwE
model was refined from existing models and validated with traditional stock assessment
data. Ecotracer (a component of the EwE software) tracked the bioaccumulation of
contaminants moving through the system with biomass. The models estimated
contaminant concentrations for species and functional groups that have not previously
been measured. Results suggest that PCB concentrations for most species in the eastern
Bering Sea have remained below threshold levels associated with negative reproduction
and survival effects. However, these concentrations may have subtle effects on adults and
more serious effects on foetuses and nursing young, which could inhibit the recovery of
Steller sea lions and other species that have declined in the eastern Bering Sea. Although
the benefits of traditional foods appear to continue to outweigh the risks posed by
contaminants for humans, PCB exposure and dietary intake for many Alaska Natives
subsisting on marine mammals is above the USEPA Daily Reference Dose. Results
extend the existing eastern Bering Sea models and are important in terms of management
alternatives for marine mammals and human health. They also synthesise evidence
regarding the presence, extent, and movement of PCBs throughout the system. The
refined eastern Bering Sea models are useful tools for exploring different scenarios and
hypotheses, to inform resource managers, and to further our understanding of this
ecosystem.