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. / Science, Faculty of / Zoology, Department of / Graduate

Fur trapping, for generations the chief source of income for native people in northern Canada, has seriously declined in recent years. An outstanding exception is the community of Sachs Harbour, Banks Island, N. W. T., where several thousand white fox pelts are harvested annually by 15 to 20 trappers. The thesis analyzes two topics: the cultural ecology of the colonization of Banks Island as a trapping frontier, and the economic geography of trapping and hunting there. Its purposes are to investigate the ecological, economic and social basis of trapping, to understand trapping as an adaptive strategy in particular historical circumstances, and to analyze it as a viable resource system. The study is based on 14 months of field research in the Western Arctic, chiefly at Sachs Harbour, N.W.T. The primary research method was participant observation, although most quantitative data were obtained through semi-formal interviews. Archival research provided additional historical information and statistics. The relative success of the various groups of settlers was strongly related to their previous orientation to white fox trapping, and hence to their place of origin within the Western Arctic. The development of inland trapping was critical to the successful exploitation of the Island, and despite subsequent centralization of settlement, the trappers have expanded their resource hinterland. This is in contrast to developments in other parts of the north. The ecology of the Arctic fox on Banks Island is discussed, and a means of measuring areal exploitation in trapping is devised. The relationship between effort inputs and trapping success are examined. The number of trap checks is the input factor most strongly correlated with the number of foxes caught, with the number of traps set showing the second best correlation. Tentative predictor equations for trapping success are derived for various levels of fox abundance within the population cycle, and for the cycle as a whole. Quantitative analyses of seal, caribou, polar bear and other types of hunting show how these activities are integrated with the total resource system, and provide data for comparison with other Arctic regions. Methods are developed for the calculation of production costs of fur pelts and animal foods (and hence the profitability of trapping and hunting), as well as for the calculation of income in kind. The discussion includes the role of marketing, credit and savings. In conclusion, the resource system on Banks Island is discussed in terms of its ecologic, economic, and social viability - both in relation to the future of trapping on Banks Island itself and to the possibility of this system as a generic type being instituted elsewhere. There is no evidence of overharvesting of any major biological resources on Banks Island, and the number of trappers and the spatial arrangement of their activities appear to be optimal. Trapping provides a good standard of living on Banks Island, and reasonable stability of income seems assured. The Banks Island resource system would thus be ecologically stable and economically viable in other parts of the Arctic with similar resources. Social forces however make such a development unlikely. Social values and occupational aspirations are rapidly changing, especially among young people, and trapping is increasingly devalued as a life style despite its economic potential. The difficulties of recruiting young trappers at Sachs Harbour are noted, and the trapping system is seen as one of decreasing social acceptability all across the north. / Arts, Faculty of / Geography, Department of / Graduate

The history of trade among Indian groups of the Canadian Yukon has included changes in the quantity and type of goods involved and, more importantly, changes in the social relations between the people who conducted this trade. These relations were between distinct native groups at first, and later directly between Indians and White traders. In this study historical data on the changes in trade is organized into convenient stages by identifying types of trade institutions. Four such stages are described and analyzed with reference to the major conditioning factors for trade in the area and at the time. These stages are (1) Inter-tribal trade, when exchanges were conducted between partners of different native groups; (2) Trading chief trade, m which an Indian group leader handled relations with White traders; (3) Monopoly trade, in which a quasi-debt relationship handled trade between traders and individual trappers; and (4) Market trade, in which trade is handled through separate fur market and retail market institutions. Institutions are treated in this study as having a set of several purposes related to the complementary aims of participants. Changes between one stage and the next are seen as a regrouping of these purposes into new sets, which become the focus of hew institutions. This view of institutional change arises from an analysis of the changes in trade relations in the Yukon, and is compared with a somewhat similar analysis of social change developed "by Talcott Parsons and Neil Smelser. / Arts, Faculty of / Anthropology, Department of / Graduate

No description available.

The Cape fur seal Arctocephalus pusillus pusillus colony at the Robberg Peninsula, Plettenberg Bay, on the south-east coast of South Africa, was driven to extirpation by indiscriminate harvesting by the late 1800s and seals only began to recolonise this site in the 1990s. This study describes the recolonisation process from 2000 to 2009, exploring within- and between-year variation in the number of seals using the site. Numbers increased over the study period from less than 300 animals to over 3 100. Year and month were important in explaining variability in seal counts, whereas sea condition, time of day and lunar phase had minimal explanatory power. Within-year variation in seal counts decreased during the study period, which may indicate an increasing proportion of resident (as opposed to transient) seals in the colony. However, the colony is currently still in a transition phase with a low ratio of breeding to non-breeding animals and low numbers of pups born on the colony (currently still < 100 per year). The influx of seals to the Robberg area may be associated with an increase in prey availability in the area. The relative protection afforded by the Nature Reserve status of the Robberg Peninsula and the existence of a Marine Protected Area adjacent to it are likely to contribute to the growth of this colony. However, human interference associated with fishing and/or ecotourism on the Peninsula may prevent the colony from developing into a breeding colony. Faecal (scat) sampling was employed to study the diet of this increasing seal population at Robberg. Species composition and size of prey were determined, temporal variation in the diet was explored, and the potential for competition between seals and the fisheries around Plettenberg Bay was investigated. Of the 445 scats collected, 90 % contained hard prey remains. These comprised of 3 127 identified otoliths representing 15 teleost prey species, 25 cephalopod beaks representing three 6 species and three feathers representing two bird species. The seals' most important prey species in terms of numerical abundance and frequency of occurrence in the diet were anchovy, sardine, horse mackerel, sand tongue-fish and shallow-water hake (in decreasing order of importance). The proportion of anchovy in the diet increased during the study period, while sardine decreased. Sardine was the only species that increased significantly in the diet during the upwelling season. Little evidence was found of direct competition between seals and linefisheries in Plettenberg Bay, both in terms of prey species composition and quantities consumed. Scat sampling in seals holds promise as a method to track long-term changes in prey species availability. The conservation and management of this colony are discussed in light of the research findings.

The New Zealand fur seal (Arctocephalus forsteri) is the most abundant fur seal species in the Australian-New Zealand region. Approximately 85 % of Australia’s population of New Zealand fur seals reside in the state of South Australia. As a result of their abundance and size, it has been estimated that the New Zealand fur seal population in South Australia consumes the greatest biomass of resources of all marine mammal and seabird species. However, despite the importance of New Zealand fur seals as top predators, our understanding of their foraging ecology in South Australia is limited. In order to better understand the habitat utilized and the diet of New Zealand fur seals, this study explores the foraging ecology of lactating seals from four primary colonies in South Australia, which account for ~ 78 % of the Australian population. These colonies are Cape Gantheaume (36о04’S, 137о27’E) and Cape du Couedic (36о03’S, 136о42’E) on Kangaroo Island; North Neptune Island (35о13’S, 136о03’E) and Liguanea Island (34о59’S, 135о37’E). I start this study by assessing the seasonal variation in foraging location and dive behaviour of lactating New Zealand fur seals from Cape Gantheaume. 18 seals were fitted with satellite transmitters and time depth recorders (TDRs). The presence of thermoclines (derived from TDRs), were used as a surrogate measure of upwelling activity in continental shelf habitats. During the austral autumn 80 % of lactating fur seals foraged on the continental shelf (114 ± 44 km from the colony), in a region associated with a seasonal coastal upwelling system, the Bonney upwelling. In contrast, during winter months seals predominantly foraged in oceanic waters (62 %), in a region associated with the Subtropical Front (460 ± 138 km from the colony). Results suggested that lactating New Zealand fur seals shift their foraging location from continental shelf to oceanic habitats, in response to a seasonal decline in continental shelf productivity, attributed to the cessation of the Bonney upwelling in autumn. To study inter-colony differences in foraging locations, 21 New Zealand fur seals were satellite tracked from four colonies within close proximity (46 km – 200km apart). Seals initiated foraging trips on a colony-specific bearing (Cape Gantheaume 141 ± 33º, Cape du Couedic 186 ± 12º, North Neptune Island 200 ± 23º and Liguanea Island 234 ± 69º), and recorded little overlap between colony-specific foraging areas. The distribution of colony-specific foraging grounds appeared to be influenced by the proximity of colonies to predictable local upwelling features, as well as a distant oceanic frontal zone, the Subtropical Front. Foraging site fidelity and route-choice was further assessed by comparing site fidelity between continental shelf and oceanic habitats. Data from 31 lactating females, satellite tracked over 107 consecutive foraging trips indicated that females foraging on the continental shelf recorded a significantly greater overlap in foraging area between consecutive foraging routes, when compared to females that foraged in oceanic waters (55.9 ± 20.4 % and 13.4 ± 7.6 %, respectively). Findings suggest that seals learn the direction of travel to a predictable foraging region, and initiate a foraging trip on that bearing. However, actual foraging routes are likely to be influenced by a number of factors including previous foraging trip experience and prey encounter rate, which is related to prey density and the spatial scale of the patch exploited. The final chapter integrates scat analysis with milk fatty acid (FA) analysis to investigate dietary differences between continental shelf and oceanic waters. Milk FA composition was determined for 29 satellite-tracked fur seals, that were known to forage in either shelf or oceanic habitats. Based on FA compositions, I predicted the likelihood that milk samples collected at random (n = 131) represented individual seals having foraged either on the continental shelf or in distant oceanic waters. FA analysis and satellite tracking results contrasted with scat analyses, from which only 6 % of scats by frequency of occurrence contained prey remains from oceanic waters. The results suggest that scats were biased toward females foraging on the continental shelf. This study highlights the importance of two predictable ocean features utilised by New Zealand fur seals; (1) a nearby and seasonally predictable coastal upwelling system, the Bonney upwelling and; (2) a distant but permanent oceanic front, the Subtropical Front. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347312 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Studies, 2008

Fur (Ferric Uptake Regulator) est un régulateur transcriptionnel spécifique des bactéries qui intervient dans le contrôle de l'homéostasie du fer, ce qui en fait une cible antibactérienne intéressante. Avant mon arrivée au laboratoire, quatre inhibiteurs interagissant spécifiquement avec Fur avaient été isolés. La partie active de ces inhibiteurs consiste en des peptides de 13 acides aminés. Au cours de cette thèse, j'ai utilisé une double-approche : théorique et expérimentale pour étudier l'interaction de ces peptides avec Fur afin de comprendre le mécanisme d'inhibition. J'ai synthétisé plusieurs séquences peptidiques, montré par des tests biochimiques que certaines inhibaient Fur et déterminé les interactions importantes à l'activité inhibitrice. J'ai obtenu des modèles théoriques des complexes Fur/peptides par amarrage moléculaire, cohérents avec les résultats expérimentaux, qui ont mis en évidence une zone d'inhibition de Fur. Des criblages in silico dans cette zone ont permis de sélectionner de petites molécules, inhibitrices potentielles de Fur et donc intéressantes pour des applications thérapeutiques. / Fur (Ferric Uptake Regulator) is a transcriptional regulator involved in the control of iron homeostasis. Specific to bacteria, Fur is an attractive antibacterial target. Before my arrival in the laboratory, four inhibitors interacting specifically with Fur had been isolated. The active part of these inhibitors consists of peptides of 13 amino acids. In this thesis I have used both theoretical and experimental approaches to study interactions of these peptides with Fur in order to understand the inhibition mechanism. I have synthesized several peptide sequences, shown through biochemical assays that some of them could inhibit Fur and I have identified residues important to the inhibitory activity. I‘ve obtained theoretical models of Fur/peptide complexes consistent with experimental results, which reveal an inhibition pocket in Fur. Small molecules have then been selected though In silico screening of this pocket, that could potentially inhibit Fur, and thus be interesting for therapeutic applications.

Pseudomonas aeruginosa est une bactérie pathogène opportuniste extracellulaire. La souche PAO1 de P. aeruginosa possède trois loci codant des Systèmes de Sécrétion de Type VI (T6SS) indépendants, nommés H1 à H3-T6SS. Le premier d'entre eux, H1-T6SS, a été largement décrit dans la littérature scientifique et injecte des toxines à activité antiprocaryote dans d'autres bactéries permettant une défense active contre l'attaque d'un T6SS d'une autre bactérie. Les deux autres T6SS de P. aeruginosa sont probablement des facteurs de virulence de cette bactérie, mais aucun effecteur sécrété, ni cible intracellulaire ou rôle n'ont été proposés jusqu'ici. Dans ce travail de thèse, nous avons mis en évidence que la machinerie H2-T6SS permet l'invasion de cellules non-phagocytaires et participe à la virulence de P. aeruginosa. Cette entrée requière la dynamique du réseau de microtubules, via VgrG2b injectée par la machinerie H2-T6SS dans les cellules épithéliales, et capable de cibler les complexes de gamma-tubulines, centre nucléateur des microtubules. Il s'agit d'un mécanisme d'internalisation tout à fait original et jamais encore décrit. Nous avons également exploré la régulation croisée entre H2 et H3-T6SS. Enfin par une analyse de « RNAseq », nous avons observé entre les souches PAO1 et PA14 de P. aeruginosa une expression différentielle de nombreux gènes, certains codant des facteurs de virulence. Pour près de 30% d'entre eux, l'origine de cette variation reposerait sur une quasi-absence d'expression dans la souche PA14 de qslA, codant un anti-activateur du Quorum-Sensing. Ceci serait une nouvelle explication du phénotype hyper-virulent de la souche PA14 de P. aeruginosa. / Pseudomonas aeruginosa is an opportunistic extracellular pathogen. The PAO1 strain of P. aeruginosa harbors three loci encoding independent Type VI Secretion Systems (T6SS), named H1 to H3-T6SS. H1-T6SS has been widely described in the literature and injects toxins with antiprokaryotic activity in target bacteria, allowing an active defense against the attack of a T6SS from another bacterium. The other two T6SS of P. aeruginosa are likely virulence factors, but no secreted effector or intracellular target or role have been proposed so far.In this work, we demonstrated that the H2-T6SS machinery triggered the invasion of non-phagocytic epithelial cells and is involved in the virulence of P. aeruginosa. This uptake is mediated by the microtubule network dynamics, and via VgrG2b, injected by the H2-T6SS machinery in epithelial cells, to target the gamma-tubulin complex, the microtubule nucleating center. This is an original mechanism of internalization never described before. We also studied the cross-regulation between H2 and H3-T6SS. Finally through a « RNAseq » analysis, we observed differential expression of many genes, including some encoding virulence factors, between PAO1 and PA14 strains of P. aeruginosa. For nearly 30% of them, the origin of this variation is an almost lack of expression in the PA14 strain of qslA, encoding an anti-Quorum Sensing activator. This can be a new explanation of hyper-virulent phenotype of the PA14 strain of P. aeruginosa.

A recognition system is required between pinniped mothers and pups. For otariids this is especially important since females frequently leave their pups for foraging and must reunite on return. Pups must deal with these fasting periods during maternal absence and consequently may attempt to obtain allomaternal care from unrelated females. This research on the New Zealand fur seal (Arctocephalus forsteri) at Ohau Point, Kaikoura, New Zealand, quantified mother-pup recognition behaviour during reunions, individuality of pup calls used by mothers to recognise their pup, and the occurrence of allosuckling as a possible recognition error by females and as a strategy employed by pups to gain allomaternal care during their mothers' absence. A combination of behavioural observations, morphometry, VHF radio telemetry, acoustics and DNA genotyping were employed to study these topics. Postpartum interaction behaviours between mothers and pups appeared to facilitate development of an efficient mother-pup recognition system, involving mainly vocal and olfactory cues that were utilised during reunions. Greater selective pressure on pups to reunite resulted in an asymmetry of searching behaviour between females and pups during reunions. The vocalisations of pups were stereotypic, especially those features of the fundamental frequency and frequency of the lowest harmonic, which are likely to facilitate recognition of a pup by their mother. Pups attempted to steal milk from unrelated females more often during maternal absence and appeared to modify the intra-individual variation pattern of a feature of their vocal signatures over this period, which may assist attempts at allosuckling under nutritional stress. Fostering was demonstrated to occur despite costs to filial pups and possible costs to female reproductive success and may be attributed to development of erroneous recognition between females and non filial pups, or kin selection. This study provides a valuable contribution to the knowledge of recognition systems between pinniped mothers and pups, of alternative pup strategies under nutritional stress and of the rare occurrence of fostering in otariid pinnipeds.

Colony dynamics, maternal investment, and indicators of health were investigated for the New Zealand fur seal (Arctocephalus forsteri) over four austral summers, 2001- 2005. Effort was focused at the Ohau Point seal colony, north of Kaikoura. Two colonies at Banks Peninsula were included for comparisons of colony growth and pup condition. A range of other colonies were also included for making comparisons about colony dynamics and health indices. Colony dynamics were investigated through mark-recapture estimates of pup production and daily census of all individuals at the Ohau Point colony. Maternal attendance patterns were observed through behavioural observations of known females (n = 120), the use of VHF radio transmitters (n = 33), and female mass and body condition estimates (n = 51). Maternal investment was also investigated through longitudinal sampling of pup mass and growth rates. Parameters used to indicate colony health were: body condition, growth, presence of parasites, and the levels and common causes of mortality. The influence of parasites on pup growth was tested using treatment of selected pups with Ivermectin anti-helmentic medication, and mortality in the region was investigated through reports of dead individuals, and post mortems of those found fresh. The Ohau Point colony is in an exponential state of growth, and pup mass and condition was higher and responded to changes in environmental variables differently than at the Banks Peninsula colonies. Lactation lengths were consistently longer at Ohau Point than is typically reported for the species (323-355 days vs. 285 days). Maternal investment strategies were indicative of a close, reliable food source, and showed flexibility between years through extension of foraging trip durations and the increased use of overnight foraging trips. Individual strategies did not significantly influence pup growth. However, increased maternal condition and the ability to respond to inter-annual changes in resource availability resulted in accelerated pup growth even during an El Niño event. The incidence of pups with intestinal parasites was low at Ohau Point, and the average mass of treated and non-treated pups did not differ. Pup mortality in the region was low (3% to 50 days old), however, mortality of older pups was greatly influenced by the proximity of humans, with 2/3 of pup mortality observed between the age of 50 days and weaning being caused by car collisions. The results suggest that population dynamics and maternal investment in the region are greatly influenced by local variables, notably the presence of an accessible food source within close proximity to the colony. Various indicators of health reflect a growing colony in good condition, and the presence of a reliable food source may influence the maximum density and carrying capacity the colony is able to sustain. However, some concerns are raised about the influence of human interactions in the region, and how this may affect mortality and colony dynamics in the future. Extra fencing along the Ohau Point colony is recommended to provide added protection from the road. Continued monitoring of mortality and health indices in the region is also recommended for comparison with other colonies as Ohau Point reaches carrying capacity and density-dependent pressures increase.