Made available in DSpace on 2009-11-18T19:01:38Z (GMT). No. of bitstreams: 1 mbgomes.pdf: 1916342 bytes, checksum: d3e274b572fe37fd42cf2d47606bb34f (MD5) Previous issue date: 2008 / This work aims to explore the context and emotions related to the experience of scuba diving as hedonic consumption, as well as to understand in which conditions the benefit arising from the regular practice of this activity impact the identity construction of the practitioner. Through in-depth interviews, data were collected from scuba divers living in the city of Rio de Janeiro, during the months of January and February of 2008. In order to obtain the expected objectives, the chosen methodology of research was qualitative, with priority of the subject and the subjectivity, using an interpretative approach for the data analysis. The research results confirm some benefits of high-risk sports practice such as flow, self-evolution and communitas. Two additional benefits are presented: the condition of alterity of the ¿underwater world¿, which attributes extraordinany meaning to scuba diving and impacts identity construction, and the scuba ¿buddy¿ practice, that helps to build-up an overall sense of trust to the other. The work is concluded with some managerial recommendations aiming the development of scuba diving industry and related tourism. These above mentioned suggestions include a new industry positioning, integrated marketing communications with specific references to alterity and flow, market segmentation, the creation of gathering spaces and a gradation scale among practitioners. / Este trabalho tem como objetivo explorar o contexto e as emoções relacionadas à experiência do mergulho scuba como atividade hedônica e as condições em que os benefícios oriundos de seu consumo habitual impactam a construção de identidade do praticante. Por meio de entrevistas em profundidade, foram coletados dados junto a mergulhadores scuba residentes na cidade do Rio de Janeiro, durante os meses de janeiro e fevereiro de 2008. Para atingir os objetivos propostos, o método de pesquisa adotado foi qualitativo, com priorização do sujeito e da subjetividade, utilizando-se uma forma interpretativa para análise de dados. Os resultados confirmaram alguns benefícios da prática de esportes de alto risco já pesquisados academicamente como o fluxo, communitas e evolução pessoal. Apresentam-se dois benefícios adicionais: a condição de alteridade do mundo submarino, que atribui significância extraordinária a essa atividade esportiva e impacta a construção identitária dos envolvidos, e a prática de dupla de mergulho, que desenvolve uma confiança generalizada no próximo e serve como referência na definição do indivíduo. Conclui-se o trabalho, fazendo-se recomendações gerenciais com o intuito de beneficiar e desenvolver a indústria e o turismo relacionado a esse esporte. Essas sugestões incluem um novo posicionamento da indústria, comunicação integrada de marketing com menções específicas à alteridade e à experiência de fluxo, segmentação de mercado, criação de espaços de convivência para praticantes e por último, a criação de uma gradação relativa aos diversos níveis de mergulhadores.

Abstract in English, Afrikaans and Sesotho / Scuba diving is a popular marine recreational activity along the eastern and southern coast of Africa. This region is characterised as the East African Marine Ecoregion (EAME) and is known for its richness in marine fauna and flora, including some of the Indian Ocean‟s most diverse and abundant coral reef ecosystems, making it a popular destination for scuba divers. The future of the scuba diving industry has come under threat as a result of environmental, social, political and economic impacts, and there is a need to better understand how these external risks impact on scuba diving tourism businesses in the EAME. Empirical evidence suggests that external risks, both international and domestic, have an effect on the tourism industry as a whole. However, limited research has been conducted on the impact of such external risks on the dive tourism industry specifically. Existing research has also focused extensively on environmental risks rather than on how external risks of a political, economic and social nature affect dive operator sustainability in the EAME. Most studies have also focused on the demand side (divers) as opposed to the supply side (dive operators). In addition, as dive tourists have greater flexibility to change their destination should risks arise, this threatens the success of dive operators in higher risk areas. To address these problems, the primary objective of the research undertaken sought to comprehensively identify the impact of external risks (environmental, economic, social and political) on dive operators in four countries within the EAME from a supply-side perspective. In order to achieve the primary objective, the following secondary objectives were achieved: 1. Identified scuba diving tourism operators in the EAME and their scope of operation. 2. Determined the external risks most relevant to dive operators in the EAME and assessed their level of impact. 3. Compared the individual external risks experienced by each of the countries in the EAME (Kenya, Tanzania, Mozambique and South Africa) using a cross-case analysis. 4. Assessed the perception of dive operators regarding whether external risks would influence a dive tourists decision to travel to the dive operators area of operation in the EAME ii The study consisted of two phases. Phase 1 comprised structured interviews with a select group of dive operators to gain insight into the external risks most prevalent in the scuba diving industry, as well as to assist in developing a quantitative structured survey (Phase 2), which was subsequently completed by dive operators in Kenya, Tanzania, Mozambique and South Africa. Data was imported into SPSS for quantitative statistical analysis. From the primary data collected, the major findings from this study determined that current economic and political risks have the greatest impact on dive operators in the EAME, and this trend is expected to continue. Environmental degradation of coral reefs, while not seen as a threat at present, constitutes a key threat for the near future. The greatest influences expressed in terms of risk categories impacting on dive tourism are domestic economic risks, international economic risks, domestic political risks and international political risks. A cross-case analysis conducted on the four countries concluded that external risks have varying effects within the different countries. Finally, the results indicated that external risks significantly influence a dive tourist's decision to travel to the EAME. By identifying and assessing the external risks that have an impact on dive operators in the EAME, this research contributes to knowledge on the dive tourism industry in the EAME, as well as dive tourism further afield and the wider field of tourism management. The study's findings create awareness of the effect that external risks have on dive operators in the region. A conceptual framework was developed which encompasses external risks in the scuba diving industry. Risk radars, risk maps and colour-coded tables were further outputs this study which can assist businesses, society and economies in responding to current and future threats and crises in a more informative and intuitive way. This can be achieved by implementing risk management strategies to mitigate or reduce exposure to external risks; strengthening stakeholder involvement along the tourism value chain; and stressing the need for government involvement towards the protection of the environment and promotion of small business growth in the region. Future research can include a wider view of the marine tourism industry and other areas of the Blue Economy. / Skubaduik is 'n gewilde mariene ontspanningsaktiwiteit langs die oos- en suidkus van Afrika. Hierdie streek staan bekend as die Oos-Afrika Mariene Ekostreek (East African Marine Ecoregion, EAME) en is bekend vir sy rykheid aan mariene fauna en flora, insluitende sommige van die Indiese Oseaan se mees diverse en welige koraalrif-ekostelsels, wat dit 'n gewilde bestemming vir skubaduikers maak. Die toekoms van die skubaduikbedryf word bedreig weens die impak van omgewings-, sosiale, politieke en ekonomiese gebeure, en daar is 'n behoefte om beter te verstaan hoe hierdie eksterne risiko's skubaduiktoerisme-besighede in die EAME beïnvloed. Empiriese bewyse suggereer dat eksterne risiko's, internasionaal sowel as plaaslik, 'n invloed op die toerismebedryf as 'n geheel het. Beperkte navorsing is egter gedoen oor die impak van sulke eksterne risiko's op spesifiek die duiktoerisme-bedryf. Bestaande navorsing het ook uitvoerig gefokus op omgewingsrisiko's eerder as hoe eksterne risiko's van 'n politieke, ekonomiese en sosiale aard duik-operateur-volhoubaarheid in die EAME beïnvloed. Die meeste studies het ook gefokus op die aanvraagkant (duikers) in teenstelling met die aanbodkant (duik-operateurs). Verder, omdat duiktoeriste meer buigsaamheid het om hulle bestemming te verander indien risiko's voorkom, bedreig dit die sukses van duik-operateurs in hoë-risiko-gebiede. Om hierdie probleme te hanteer is die primêre doel van die navorsing wat gedoen is om op omvattende wyse die impak van eksterne risiko's (omgewing, ekonomies, sosiaal en polities) op duik-operateurs in vier lande in die EAME te identifiseer uit 'n aanbodkant-perspektief. Om die primêre doelwit te behaal, is die volgende sekondêre doelwitte bereik: 1. Skubaduik-toerisme-operateurs in die EAME en hulle operasionele omvang is geïdentifiseer. 2. Die eksterne risiko's wat die relevantste vir duik-operateurs in die EAME is, is bepaal en hulle vlak van impak is geassesseer. 3. Die individuele eksterne risiko's wat deur elkeen van die lande in die EAME (Kenia, Tanzanië, Mosambiek en Suid-Afrika) ervaar is, is vergelyk deur die gebruik van 'n kruisgeval-analise. 4. Die persepsie van duik-operateurs wat betref of eksterne risiko's 'n duiktoeris se besluit sal beïnvloed om na die duik-operateur se operasionele gebied in die EAME te reis, is geassesseer. Die studie het uit twee fases bestaan. Fase 1 het gestruktureerde onderhoude met 'n geselekteerde groep duik-operateurs behels om insig te kry in die eksterne risiko's wat die algemeenste in die skubaduikbedryf voorkom, en om te help om 'n kwantitatiewe gestruktureerde peiling (fase 2) te ontwikkel, wat gevolglik deur duik-operateurs in Kenia, Tanzanië, Mosambiek en Suid-Afrika voltooi is. Data is ingevoer in SPSS vir kwantitatiewe statistiese analise. Uit die primêre data wat ingesamel is, het die belangrikste bevindings van hierdie studie bepaal dat die huidige ekonomiese en politieke risiko's die grootste impak op duik-operateurs in die EAME het, en daar word verwag dat hierdie tendens sal voortduur. Die omgewingsagteruitgang van koraalriwwe, hoewel dit nie tans as 'n bedreiging beskou word nie, is 'n sleutelbedreiging vir die nabye toekoms. Die grootste invloede wat uitgedruk is as risiko-kategorieë wat 'n invloed op duiktoerisme het, is plaaslike ekonomiese risiko's, internasionale ekonomiese risiko's, plaaslike politieke risiko's en internasionale politieke risiko's. 'n Kruisgeval-analise wat op die vier lande uitgevoer is, het bevind dat eksterne risiko's wisselende uitwerkings binne die verskillende lande het. Laastens het die resultate aangedui dat eksterne risiko's 'n duiktoeris se besluit om na die EAME te reis, aansienlik beïnvloed. Deur die eksterne risiko's te identifiseer en te assesseer wat 'n impak op duik-operateurs in die EAME het, dra hierdie navorsing by tot kennis oor die duiktoerismebedryf in die EAME, asook duiktoerisme verder weg en die wyer veld van toerismebestuur. Die studie se bevindings skep 'n bewustheid van die uitwerking wat eksterne risiko's op duik-operateurs in die streek het. 'n Konseptuele raamwerk is ontwikkel wat eksterne risiko's in die skubaduikbedryf omvat. Risiko-radars, risiko-kaarte en tabelle wat volgens kleur gekodeer is, was verdere uitsette van hierdie studie wat besighede, die gemeenskap en ekonomieë kan help om te reageer op huidige en toekomstige bedreigings en krisisse op 'n meer ingeligte en intuïtiewe manier. Dit kan bereik word deur risikobestuurstrategieë te implementeer om blootstelling aan eksterne risiko's te mitigeer of te verminder; belanghebberbetrokkenheid op die toerismewaardeketting te versterk; en om die behoefte vir regeringsbetrokkenheid by die insluit. / Ho sesa tlasa metsi a lewatle ke mosebetsi o tsebahalang haholo wa boithabiso ba lewatle haufi le mabopo a ka botjhabela le borwa ba Afrika. Sebaka sena se kgethollwa e le lefatshe la bophelo ba mawatle a Afrika Botjhabela (EAME) mme se tsejwa ka leruo la sona la diphoofolo tsa lewatle le dimela, ho kenyelletsa le tse ding tsa diphedi tse fapaneng tsa lewatle la Indian, e leng se etsang hore e be sebaka se tumeng bakeng sa batho ba sesang tlasa lewatle. Bokamoso ba indasteri ya ho tola tlasa lewatle bo kotsing ka lebaka la tshusumetso ya tikoloho, kahisano, dipolotiki le moruo, mme ho na le tlhokahalo ya ho utlwisisa hantle hore dikotsi tsena tsa kantle di ama jwang dikgwebo tsa bothori bo amanang le ho sesa tlasa lewatle EAME (Mabatoweng a Afrika Botjhabela a diphedi tsa mawatle). Bopaki bo hlakileng bo fana ka maikutlo a hore dikotsi tsa kantle, tsa matjhaba le tsa lehae, di na le tshwaetso indastering ya bohahlauli ka kakaretso. Leha ho le jwalo, dipatlisiso tse fokolang di ile tsa etswa mabapi le sefutho sa dikotsi tse jwalo tsa kantle indastering ea bohahlaudi ba ho sesa ka ho kgetheha. Dipatlisiso tse teng di boetse di tsepamisitse maikutlo haholo ka dikotsi tsa tikoloho di sa shebe hore na dikotsi tsa kantle tsa dipolotiki, tsa moruo le tsa kahisano di ama jwang ho tsitsisa tshebetso ho EAME. Diphuputso tse ngata di boetse di tsepame lehlakoreng la tlhokahalo (disesi) ho fapana le lehlakore la diphallelo (batho ba sesang). Ho phaella moo, jwalo ka ha disesi tsa bahahlaudi di ena le maemo a mangata a ho fetola dibaka tsa bona ha ho hlaha dikotsi, sena se senya katleho ya disesi dibakeng tse nang le dikotsi tse ngatanyana. Ho rarolla mathata ana, sepheo se ka sehloohong sa dipatlisiso tse entsweng di ile tsa leka ho lemoha ka ho hlaka sefutho sa dikotsi tsa kantle (tikoloho, moruo, kahisano le dipolotiki) ho disesi dinaheng tse nne tse ka hare ho EAME ho tloha lehlakoreng la phepelo. E le ho finyella sepheo se ka sehloohong, dipheo tse latelang di ile tsa fihlellwa: 1. Ho kgetholla basebeletsi ba bahahlaudi ba ho sesa lebatoweng la EAME le tsela ya tshebetso ya bona. 2. Ho etsa qeto ya dikotsi tse ka ntle tsa bohlokwa ho tsamaisa ba disesi ho EAME le ho hlahloba boemo ba tsona ba tshusumetso. 3. Ho bapiswa dikotsi tse ka ntle tsa naha ka nngwe ho EAME (Kenya, Tanzania, Mozambique le Afrika Borwa) ho sebedisa dintlha tsa ho hlahloba diketsahalo. 4. Hlahloba maikutlo a disesi mabapi le hore na dikotsi tse ka ntle di tla susumetsa qeto ya bahahlaudi ba ho etela sebakeng seo ba sebetsang ho sona ho EAME Thuto e ne e ena le mekgahlelo e mmedi. Mokgahlelo wa 1 o ne o ena le dipuisano tse hlophisitsweng le sehlopha se kgethilweng sa basebetsi ba disesi ho utlwisisa dikotsi tse ka ntle tse atileng haholo indastering ya ho sesa, le ho thusa ho ntlafatsa tlhahlobo e entsweng ka bongata (Phase 2), e ileng ya qetella e phethilwe ke basebetsi ba disesi Kenya, Tanzania, Mozambique le Afrika Borwa. Lesedi le ile la kenngwa ka SPSS bakeng sa tlhahlobo ya dipalopalo. Ho tswa leseding la motheho le bokelletsweng, diphuputso tse kgolo tsa thuto ena di bontshitse hore dikotsi tsa moraorao tsa moruo le tsa lipolotiki di na le tshusumetso e kgolo ho ba sebetsang e le basebetsi ba disesi EAME, mme mokgwa ona o lebeletswe hore o tswele pele. Ho senyeha ha tikoloho ya dimela/diphedi tsa lewatle, ha ho sa nkuweng e le tshoso hona jwale, ke tshoso e ka sehloohong bakeng sa nako e tlang. Tshusumetso e matla ka ho fetisisa e hlalositsweng ka mekgahlelo ya dikotsi tse amang tsela ya ho etela dibaka tsa bohahlaudi ke dikotsi tsa moruo wa lehae, dikotsi tsa matjhaba tsa moruo, dikotsi tsa dipolotiki tsa lehae le dikotsi tsa matjhaba tsa dipolotiki. Phuputso e entsweng dinaheng tse nne e qetile ka hore dikotsi tsa ka ntle di na le diphello tse fapaneng dinaheng tse fapaneng. Qetellong, diphello di bontshitse hore dikotsi tsa ka ntle di susumetsa haholo qeto ya mohahlaudi wa ya sesang tlasa lewatle ho etela EAME. Ka ho kgetholla le ho hlahloba dikotsi tse ka ntle tse nang le tshwaetso basebetsing ba disesi EAME, dipatlisiso tsena di tlatsetsa tsebong lefapheng la bohahlaudi ba ho ho sesa tlasa lewatle dibakeng tsa EAME, ha mmoho le bahahlaudi ba ho sesa ka ho phatlalla tsamaisong ya bohahlaudi. Diphuputso tsa thuto di etsa hore ho be le tlhokomediso ya phello ya ka moo dikotsi tse ka ntle di nang le kameho disesing sebakeng seo. Ho na le moralo o ileng wa etswa o kenyeletsang dikotsi tsa kantle indastering ya ho sesa tlasa lewatle. Diwaelese tse nkgellang dikotsi, dimmapa tsa dikotsi le ditafole tse nang le mebala di ne di boetse di hlahisa thuto ena e ka thusang dikgwebo, setjhaba le moruo ho arabela dikotsing tsa moraorao le tsa nakong e tlang ka ditsela tse rutang le tse nang le tsebo. Sena se ka fihlellwa ka ho kenya tshebetsong maano a tsamaiso ya kotsi bakeng sa ho fokotsa ho pepeseha dikotsing tsa kantle; ho matlafatsa tshebetsong ya bankaseabo motjheng wa bohlokwa wa bohahlaudi; le ho totobatsa tlhokahalo ya ho nka seabo ha mmuso ho sireletsa tikoloho le tshehetso ya kgolo ya dikgwebo tse nyenyane sebakeng seo. Phuputso ya nako e tlang e ka kenyelletsa pono e pharaletseng ya indasteri ya bahahlaudi ba lewatle le dibaka tse ding tsa Blue Economy. / Environmental Sciences / M. Com. (Tourism Management)

Du fait de l’isolement géographique de l’océan austral et des conditions météorologiques qui y règnent, la collecte de données océanographiques par les moyens conventionnels est particulièrement couteuse dans cette région du globe. Pour pallier à ces difficultés, l’utilisation d’enregistreurs électroniques embarqués sur des prédateurs marins, et notamment sur les éléphants de mer austraux, s’est révélée être une approche intéressante. Les femelles éléphants de mer s’alimentent en grande partie de petits poissons méso-pélagiques bioluminescents, les myctophidés. Leur forte abondance et leur comportement de migration nycthémérale confèrent à ces organismes un rôle écologique de première importance dans l’océan austral. Cependant, la distribution spatiale des proies de l’éléphant de mer, et les processus physiques et biologiques qui influent sur la dynamique de cette distribution sont encore mal connus. Cette thèse se propose d’enquêter sur ces sujets à partir des données à haute fréquence d’échantillonnage collectées par des femelles éléphants de mer. L’analyse du comportement de plongée des femelles éléphants de mer, en relation avec les variations du taux de rencontre de proie dont les données d’accélération permettent d'avoir une estimation, est au cœur des différents travaux développés dans cette thèse. Les résultats obtenus suggèrent notamment, (1) une diminution de l’abondance des proies avec la profondeur ainsi qu’une homogénéisation de leur distribution, (2) une distribution en couches de cette ressource, (3) l’intervention de contraintes verticales délimitant l’étendue verticale de ces couches et ainsi capable de moduler leur densité, (4) au sein des couches, une dispersion relativement importante des proies en comparaison de la portée des capacités de perception du prédateur, et enfin (5) un rôle significatif des tourbillons méso-échelle et de leur bordure sur la structuration de la distribution des ressources alimentaires de l’éléphant de mer durant l’été austral. / Because of the remoteness and harsh meteorological conditions of the southern ocean, data sampling is more costly in this area. Use of electronic devices attached to marine predators (Bio-logging), such as southern elephant seals, has emerged as an interesting approach to cope with this problem. Female southern elephant seals primarily feed on small bioluminescent meso-pelagic fishes called myctophids. Because of their large abundance and of their diel vertical migration behaviour, these organisms have a major ecological importance in the southern ocean. However, the spatial distribution of the elephant seals prey, as well as the bio-physical processes affecting the dynamics of this distribution, are still poorly known. This thesis intends to investigate this issue using high sampling frequency bio-logging data collected by female southern elephant seals. This work is based on the analysis of elephant seals diving behaviour in relation to changes in the occurrence of prey encounter events detected from acceleration data. Our results suggest that (1) prey abundance decreases with depth and that their distribution tend to standardize, (2) prey are distributed into layers, (3) vertical constraints could modulate the prey density by acting on the vertical spread of these layers, (4) prey items are well dispersed in comparison to the perception range of elephant seals, and finally (5) that meso-scale eddies, notably their edges, play a structuring role in the prey distribution during the austral summer.

Pour étudier l'impact des changements environnementaux dans un écosystème marin côtier, il est nécessaire d'utiliser des espèces indicatrices. Il est essentiel de distinguer les performances de recherche de nourriture qui résultent des changements de l’environnement. L'objectif de ma thèse était d'étudier l'influence des facteurs intrinsèques et extrinsèques sur l'activité de recherche alimentaire des manchots pygmée (Eudyptula minor). J'ai démontré que la thermocline a permis aux oiseaux d'approcher le comportement optimal. Cependant, la thermocline est un élément instable. Je n'ai trouvé aucun effet des caractéristiques des individus sur le comportement et le succès. Mon travail suggère que les conditions environnementales sont les principaux facteurs qui influencent le comportement des manchots pygmée qui sont donc de bons indicateurs. / To study the impact of environmental changes in a coastal marine ecosystem, it is necessary to use indicator species. It is crucial to understand the foraging performances that proceed from environmental changes. The aim of my thesis was to examine the influence of intrinsic and extrinsic factors on the foraging activity of the little penguins (Eudyptula minor). The thermocline allowed birds to approach optimal behaviour. However, the thermocline is an unstable element. I did not find any effect of individual characteristics on their foraging behaviour and success. My work suggests that environmental conditions are major factors that will influence the behaviour of little penguins, allowing me to conclude that little penguins are good ecological indicators.

L’océan austral est un écosystème fragile dont la dynamique est influencée par des variations climatiques qui vont structurer la distribution spatio-temporelle des ressources. L’objectif de cette thèse était d’étudier les stratégies d’acquisition des ressources en proies mises en place par l’éléphant de mer austral face aux contraintes énergétiques (coûts du transport et coûts d’accès à la ressource) et temporelles (temps passé au fond d’une plongée et limite de plongée aérobie) auxquelles il est soumis. L’utilisation d’un ensemble d’enregistreurs de données déployés sur ces animaux a permis de reconstruire en trois dimensions leur plongée, mais également de calculer leur effort de nage, le nombre de proies rencontrées ainsi que leur dépense énergétique. Notre étude montre qu’à l’échelle d’une plongée, les éléphants de mer adaptent leur trajectoire, mais également le temps qu’ils passent au fond, en fonction du nombre de proies rencontrées. Pour des densités locales de proie importantes, ils passent plus de temps au fond, et concentrent leur recherche en zone restreinte, caractérisée par une diminution de la vitesse et une augmentation de la sinuosité horizontale. Au-delà de 550 m, le coût d’accès aux ressources devient supérieur aux coûts d’acquisition ; ils doivent alors faire face à un compromis entre l’accessibilité et la disponibilité en proies. À mesure qu’ils s’alimentent, ces phoques augmentent leur flottabilité, diminuant de surcroît leur dépense énergétique. Cette étude démontre également une structuration spatio-temporelle de cette dépense énergétique qui semble être liée au succès d’alimentation et donc à la distribution des ressources en proies. / The Southern Ocean is a fragile ecosystem whose dynamics are influenced by climate change that will structure the spatio-temporal distribution of resources. The objective of this PhD was to investigate the foraging strategies used by the southern elephant seal, under energetic (cost of transport and costs of access to the resource) and temporal (time at the bottom of a dive and aerobic dive limit) constraints. Using a set of animal-borne data loggers allowed us to reconstruct their three-dimensional path underwater, but also to calculate their swimming effort, the number of prey encountered and their energy expenditure. At the dive level, our study shows that elephant seals adapt their path, but also the time spent at the bottom, depending on the number of prey encountered. For high local prey density, they spent more time at the bottom, and concentrated their foraging effort in areas restricted search, characterized by a decrease in speed and an increase in horizontal sinuosity. Beyond 550 m, the cost of access to resources becomes greater than the cost of acquisition ; they must therefore deal with a trade-off between prey accessibility and availability. While feeding, these seals increase their buoyancy, reducing furthermore their energy expenditure. This study also shows a spatio-temporal structure of the energy expenditure that appears to be related to feeding success and therefore to prey resources distribution.

During the summers of 2007-2009, I studied the population growth and reproductive and foraging ecology of the Razorbill (Alca torda) at Matinicus Rock (MR), Maine. This medium-sized marine bird in the family Alcidae (auks) was extirpated from the Gulf of Maine in the late 19th century by hunting, collecting, and colony disturbance. Following legislation protecting seabirds and their nesting habitats, the Razorbill has recolonized probable former nesting habitat in the Gulf of Maine during the past several decades. Six small colonies comprise the Maine population, which is listed as threatened and forms the southern extension of the species breeding distribution. In Chapter 1, I present a population model of the MR breeding colony, based on studies of population growth and reproductive success, and supplemented with previously collected data from the National Audubon Society Seabird Restoration Program (Project Puffin), with whom I collaborated. I also describe chick diet (supplemented with Project Puffin data) and draw connections between diet and reproductive success. I found that reproductive success was too low to account for the observed population growth rate, and conclude that the colony is a sink population supported by substantial immigration. Because annual fledging success was positively associated with prey quality, I suggest that substandard chick diet may contribute to the sink population dynamic via diet-driven depressed fledging success. In Chapter 2, I report on the foraging behavior of chick-rearing Razorbills fitted with bird-borne data-loggers at MR in 2008-2009. I describe diving behavior including depth, duration, and profile shape of dives, as well as diel patterns. Diving activity was restricted to daylight hours, and dives were shallowest and most frequent in the evening. Though generally similar to diving behavior reported at four European and Canadian colonies, Razorbills at MR performed three times as many dives per day as at the Gannet Islands, Labrador, and the mean dive depth was greater than three of four previous studies. Deeper and more frequent dives may indicate higher foraging effort and lower prey availability. Reproductive success would suffer if parents cannot buffer chicks against the effects of low prey availability through increased foraging effort or other behavioral modifications. Together, the pieces of our research indicate that prey availability may be negatively affecting reproduction and population growth at MR. Rapid colony growth cannot be explained by local reproductive success, and is likely the result of substantial immigration from other colonies. Chick diet is varied and includes multiple high-quality forage fish species, yet chicks also consume poor-quality prey (larval fish and euphausiids) that may signal periods of very poor prey availability. Frequency and depth of dives made by chick-provisioning adults are also suggestive of parents allocating extra effort to foraging, relative to other colonies.

En informatique, la résolution de problèmes NP-difficiles en un temps raisonnable est d’une grande importance : optimisation de la chaîne d’approvisionnement, planification, routage, alignement de séquences biologiques multiples, inference dans les modèles graphiques pro- babilistes, et même certains problèmes de cryptographie sont tous des examples de la classe NP-complet. En pratique, nous modélisons beaucoup d’entre eux comme un problème d’op- timisation en nombre entier, que nous résolvons à l’aide de la méthodologie séparation et évaluation. Un algorithme de ce style divise un espace de recherche pour l’explorer récursi- vement (séparation), et obtient des bornes d’optimalité en résolvant des relaxations linéaires sur les sous-espaces (évaluation). Pour spécifier un algorithme, il faut définir plusieurs pa- ramètres, tel que la manière d’explorer les espaces de recherche, de diviser une recherche l’espace une fois exploré, ou de renforcer les relaxations linéaires. Ces politiques peuvent influencer considérablement la performance de résolution. Ce travail se concentre sur une nouvelle manière de dériver politique de recherche, c’est à dire le choix du prochain sous-espace à séparer étant donné une partition en cours, en nous servant de l’apprentissage automatique profond. Premièrement, nous collectons des données résumant, sur une collection de problèmes donnés, quels sous-espaces contiennent l’optimum et quels ne le contiennent pas. En représentant ces sous-espaces sous forme de graphes bipartis qui capturent leurs caractéristiques, nous entraînons un réseau de neurones graphiques à déterminer la probabilité qu’un sous-espace contienne la solution optimale par apprentissage supervisé. Le choix d’un tel modèle est particulièrement utile car il peut s’adapter à des problèmes de différente taille sans modifications. Nous montrons que notre approche bat celle de nos concurrents, consistant à des modèles d’apprentissage automatique plus simples entraînés à partir des statistiques du solveur, ainsi que la politique par défaut de SCIP, un solveur open-source compétitif, sur trois familles NP-dures: des problèmes de recherche de stables de taille maximum, de flots de réseau multicommodité à charge fixe, et de satisfiabilité maximum. / In computer science, solving NP-hard problems in a reasonable time is of great importance, such as in supply chain optimization, scheduling, routing, multiple biological sequence align- ment, inference in probabilistic graphical models, and even some problems in cryptography. In practice, we model many of them as a mixed integer linear optimization problem, which we solve using the branch and bound framework. An algorithm of this style divides a search space to explore it recursively (branch) and obtains optimality bounds by solving linear relaxations in such sub-spaces (bound). To specify an algorithm, one must set several pa- rameters, such as how to explore search spaces, how to divide a search space once it has been explored, or how to tighten these linear relaxations. These policies can significantly influence resolution performance. This work focuses on a novel method for deriving a search policy, that is, a rule for select- ing the next sub-space to explore given a current partitioning, using deep machine learning. First, we collect data summarizing which subspaces contain the optimum, and which do not. By representing these sub-spaces as bipartite graphs encoding their characteristics, we train a graph neural network to determine the probability that a subspace contains the optimal so- lution by supervised learning. The choice of such design is particularly useful as the machine learning model can automatically adapt to problems of different sizes without modifications. We show that our approach beats the one of our competitors, consisting of simpler machine learning models trained from solver statistics, as well as the default policy of SCIP, a state- of-the-art open-source solver, on three NP-hard benchmarks: generalized independent set, fixed-charge multicommodity network flow, and maximum satisfiability problems.

<p>Sudden unexpected death in epilepsy (SUDEP) is a fatal complication of epilepsy that kills 1̃2 of every 10,000 epileptic patients every year. SUDEP has proven difficult to study because it frequently occurs unobserved and cannot be predicted. What limited clinical data exists suggests that SUDEP occurs as a cardiorespiratory collapse immediately following a seizure. In this work, I explore how a group of autonomic reflexes termed collectively as “oxygen‐conserving reflexes (OCRs)” lead to sudden death when activated during seizures. I also demonstrate multiple physiological parallels between the OCR‐mediated deaths that I report and the clinical data on cases of human SUDEP. Additionally, I explore the neural pathway underlying OCRs, identify the carotid body as a potential target for intervention, and demonstrate the efficacy of electroceutical intervention in reducing the mortality risk of OCR activation during seizures. This work seeks to both offer a neural explanation for SUDEP as well as present a promising target and means for potential intervention.</p>

Understanding the movement behavior and foraging strategies of individuals across multiple spatial and temporal scales is essential not only for understanding the biological requirements of individuals but also for linking individual strategies to population level effects. Glacial fjords scattered throughout south-central and southeastern Alaska host some of the largest seasonal aggregations of harbor seals (Phoca vitulina richardii) in the world, and an estimated 15% of the harbor seal population in Alaska is found seasonally at these glacial ice sites. Over the last two decades, the number of harbor seals has declined at two of the primary glacial fjords, in Aialik Bay in south-central Alaska and in Glacier Bay in southeastern Alaska, thus raising concerns regarding the viability of seal populations in glacial fjord environments. From 2004-2009, the foraging ecology, diving behavior, and migration patterns of harbor seals from Glacier Bay National Park, Alaska were examined in relation to prey availability and oceanographic features in Glacier Bay and the surrounding regions of southeastern Alaska. Time-depth recorders, very high frequency transmitters, and satellite-linked transmitters were used to quantify the vertical and horizontal movement patterns of harbor seals in the marine environment. Specifically, (1) I characterized the diving behavior, foraging areas, and foraging strategies of female harbor seals from terrestrial and glacial ice sites relative to prey availability during the breeding season (May-June) in Glacier Bay, (2) I quantified the intra-population variation in at-sea post-breeding season (September-April) distribution and movement patterns of female harbor seals in relation to oceanographic features, (3) I quantified the post-breeding season migration patterns of female harbor seals relative to the boundaries of the marine protected area of Glacier Bay National Park, and (4) I characterized the use of the continental shelf region of the eastern Gulf of Alaska by female harbor seals from Glacier Bay, both as a foraging area and as a migratory corridor in relation to oceanographic features. During the breeding season, there was a substantial degree of intra-population variation in the diving behavior and foraging areas of juvenile and adult female seals from glacial ice and terrestrial sites in Glacier Bay. The presence of multiple diving strategies suggests that differences in the relative density and depth of prey fields in glacial ice and terrestrial habitats in addition to seal age and reproductive status may influence diving and foraging behavior of harbor seals. During the post-breeding season, juvenile and adult female harbor seals ranged extensively beyond the boundaries of the marine protected area of Glacier Bay National Park, throughout the northern inshore waters of southeastern Alaska and the continental shelf region of the eastern Gulf of Alaska between Cross Sound and Prince William Sound, Alaska (up to 900 kilometers away). Seals exhibited a relatively high degree of intra-population variation in their at-sea post-breeding season distribution patterns that may be a function of extrinsic factors such as oceanographic characteristics, which can influence prey availability as well as intrinsic factors including previous experience with foraging areas and seal condition and age. Use of the continental shelf region of the eastern Gulf of Alaska by harbor seals as a foraging area may be due to enhanced biological productivity which may be associated with ephemeral hydrographic and/or static bathymetric features. Despite extensive migrations of seals from Glacier Bay during the post-breeding season, there was a high degree of inter-annual site fidelity of seals to Glacier Bay the following breeding season after seals were captured. / Graduation date: 2012

Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2005. / Typescript (photocopy).