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The marine environment provides essential ecosystem services that are critical to the functioning of the earth’s life support system and the maintenance of human well-being. Marine Protected Areas (MPAs) are recognised as being the mechanism though which marine natural capital may be conserved. This thesis focuses on the value associated with marine conservation in a case study area, Lyme Bay, England where a ‘closed area’ was created in 2008. A review of literature spanning 20 years shows that despite sound ecological knowledge of a marine area, the reliance on traditional neo-classical economic valuations for marine spatial planning can obscure other issues pertinent to the ecosystem approach. A further valuation of the marine leisure and recreation industry shows that the industry is of economic significance and that the MPA enables the protection of the most valuable sites but has limited benefits for protecting the full resource base. In terms of ecological value, a ‘service orientated framework’ was developed to enable decision makers to understand the links between benthic species, ecological function and indirect ecosystem services. Results spatially identify which ecosystem services occur and demonstrate the value of the MPA in ensuring delivery of these ecosystem services. In relation to the social value of the MPA the research reveals that support for the MPA is strong amongst the majority of stakeholder groups. Values are expressed as the economic, environmental and social benefits of the MPA. However, there have been clear social costs of the MPA policy and these have been borne by mobile and static gear fishermen and charter boat operators. Each valuation methodology can inform decision making. Though, if ecosystem service valuation is to become a deliberative tool for marine conservation and planning, then there is a need for a larger societal discussion on what activities and trade-offs society considers acceptable.

La gestion du milieu marin pour de multiples usages est une problématique de plus en plus en complexe. La création d’aires marines protégées (AMP) a été désignée comme étant une stratégie efficace afin de concilier la conservation avec les autres usages. Cependant, pour atteindre les objectifs de conservation, un plan de gestion bien défini de même qu’un programme de suivi efficace doivent être instaurés. En 1998, le parc marin du Saguenay–Saint-Laurent (PMSSL) a été créé afin de protéger plusieurs écosystèmes important de l’Estuaire du Saint-Laurent. Une industrie d’observation en mer de baleines en pleine croissance était déjà établie dans la région, qui est également traversé par une voie de navigation commerciale importante. Treize espèces de mammifères marins sont présentes dans la région, parmi lesquelles, quatre espèces de rorquals sont le centre d’intérêt du présent travail : le petit rorqual (Balaenoptera acutorostrata), le rorqual commun (Balaenoptera physalus), le rorqual à bosse (Megaptera novaeangliae) et le rorqual bleu (Balaenoptera musculus). La réduction des risques de collision et des perturbations du comportement susceptibles d’entrainer des conséquences physiologiques constitue un des enjeux majeures pour la conservation des baleines dans cette région. Avant de s’intéresser aux impacts du trafic maritime, des questions de base doivent être étudiées: Combien de baleines utilisent le secteur? Où sont les zones de fortes concentrations? Pour répondre à ces questions, des données d’échantillonnage par distance le long de transect linéaire sur une période de quatre ans (2006-2009) ont été utilisées pour estimer la densité et l’abondance et pour construire un modèle spatiale de la densité (MSD). Les espèces les plus abondantes sont le petit rorqual (45, 95% IC = 34-59) et le rorqual commun (24, 95% IC=18-34), suivi du rorqual bleu (3, 95% IC=2-5) et du rorqual à bosse (2, 95% IC=1-4). Les modèles additifs généralisés ont été utilisées afin de modéliser le nombre d’individus observé par espèce en fonction des variables environnementales. Les MSD ont permis l’identification des zones de concentration de chaque espèce à l’intérieur des limites de la portion de l’estuaire maritime du PMSSL et à valider les abondances estimées à partir des recensements systématiques. De plus, ils ont validé la pertinence de la zone de protection marine de l’estuaire du Saint-Laurent proposée (ZPMESL) pour la conservation du rorqual bleu, une espèce en voie de disparition. Un exercice d’extrapolation a également été effectué afin de prédire les habitats du rorqual bleu à l’extérieur de la zone d’échantillonnage. Les résultats ont montré une bonne superposition avec des jeux de données indépendants. Malgré la nature exploratoire de cet exercice et dans l’attente de meilleures informations, il pourrait servir de base de discussion pour l’élaboration de mesures de gestion afin d’augmenter la protection de l’espèce. Ensuite, les systèmes d’informations géographiques ont été utilisés afin de vérifier le degré de chevauchement entre la navigation commerciale et les résultats des MSD de chaque espèce et l’exercice d’extrapolation. Les analyses ont identifiées les zones de forte cooccurrence entre les navires et les rorquals. Ces résultats démontrent la pertinence des mesures de gestion récemment proposées et ont mené à une recommandation d’ajustement de l’actuel corridor de navigation afin de diminuer le risque de collision. Finalement, le chevauchement avec l’industrie d’observation de baleines a été caractérisé avec des données d’un échantillonnage à partir de points terrestres conduit de 2008 à 2010. Bien que toutes les espèces de rorquals aient été suivies, seulement les résultats concernant les rorquals bleus et les rorquals à bosses sont présentés ici. Pour les rorquals bleus, 14 heures de données d’observation ont été analysées. Les rorquals bleus étaient exposés aux bateaux (<1 km), principalement les zodiacs commerciaux, dans 74 % des intervalles de surface (IS) analysés. L’exposition continue était de 2 à 19 IS et le nombre moyen de bateaux à l’intérieur d’un rayon de 1 km était 2.3 (±2.7, max=14). Lorsqu’en observation de l’animal focal, tous les bateaux commerciaux ont utilisé la zone à l’intérieur de 400 m, enfreignant ainsi le règlement qui prescrit une distance de retrait minimale de 400 m dans le cas d’espèces en voie de disparition. De plus, la variance du taux respiratoire de chaque individu était corrélée avec le pourcentage d’exposition au bateaux (0.73, p<0.05) suggérant une modification comportementale susceptible d’entrainer des conséquences physiologiques. Bien que le rorqual à bosse n’ait pas un statut de conservation critique, sont comportements en fait une cible importante de l’industrie d’observation. Un total de 50.4 heures d’observation du rorqual à bosse a été analysé. Les rorquals à bosse étaient exposés aux bateaux, principalement aux zodiacs commerciaux, pendant 78.5% du temps d’observation. Le nombre moyen de bateaux dans un rayon de 1 km était de 1.9 (±2.3, max=22). L’exposition cumulative aux activités d’observation de baleines peut avoir des conséquences à long terme pour les rorquals. L’application du règlement et des mesures pour augmenter la sensibilisation et le respect de la règlementation actuelle sont nécessaires. Des suggestions pour améliorer la règlementation actuelle sont proposées. Ce travail présente pour la première fois des estimés d’abondance pour l’aire d’étude, améliore les informations disponibles sur les zones de fortes concentrations, donne un appui à l’établissement d’un plan de zonage adéquat à l’intérieur des limites du PMSSL et souligne l’importance de l’établissement de la ZPMESL proposée. Par sa revue compréhensive de la question du trafic maritime en lien avec les rorquals présents dans l’estuaire, cette étude fournit des informations précieuses pour la gestion de ce système socio-écologique complexe. / Management of the marine environment for multiple usages has become increasingly complex. The creation of Marine Protected Areas (MPAs) has been pointed out as a successful strategy for combining conservation with other uses. However, to attain conservation goals, a well-defined management plan and a robust monitoring program need to be set. In 1998, the Saguenay St. Lawrence Marine Park (SSLMP) was decreed to protect important ecosystems of the St. Lawrence River Estuary. A growing whale watching industry was already established in the area which is also crossed by an important shipping lane. Thirteen marine mammal species occur in the area, among them, four baleen species, which are the focus of the present work: minke whales (Balaenoptera acutorostrata), fin whales (Balaenoptera physalus), humpback whales (Megaptera novaeangliae) and the blue whales (Balaenoptera musculus). Whales’ protection in this area of intensive marine traffic is of concern due to a high collision probability and induced behavioral and physiological changes. Before addressing the effects of the marine traffic, some basic questions needed to be answered: How many baleen whales use the area? Where are their core areas? To answer that, line-transect distance-sampling data collected over four years (2006-2009) were used to estimate density and abundance and to build a spatial density model (SDM). The most abundant species were minke (45, 95% CI=34-59) and fin whales (24, 95% CI=18-34), followed by blue (3, 95% CI=2-5) and humpback whales (2, 95% CI=1-4). Generalized additive models were used to model each species count as a function of space and environmental variables. The SDM allowed the identification of each species core area within the marine portion of the SSLMP, and corroborated the abundance estimates derived from design-based methods. In addition, it corroborated the relevance of the proposed St. Lawrence Estuary Marine Protected (SLEMPA) Area to the conservation of essential habitats of the endangered blue whale. An extrapolation exercise was performed to predict blue whales’ habitats outside the surveyed area. Despite its exploratory nature, the results showed a good match with independent data sets and in the lack of better information could guide the discussion of management measures to enhance species’ protection. Next, Geographic Information System capabilities were used to verify the degree of overlap between the navigation corridor and the resulting SDM of each species and the extrapolation model. The analysis highlighted areas of important co-occurrence of whales and ships, corroborated the adequacy of recently proposed management measures and resulted in a recommendation of adjustment to the current shipping lane in order to decrease collision risk. Finally, the overlap with the whale watching industry was characterized with data from a land-based survey conducted from 2008 to 2010. Although all baleen whale species were tracked, here only results of blue and humpback whales were presented. For blue whales, data from 14 hours of observation were analyzed. Whales were exposed to boats, mainly commercial zodiacs, in 74% of their surface intervals (SI). Continuous exposure ranged from 2 to 19 SI and the mean number of boats within a 1 km radius was 2.3 (±2.7, max=14). A complete lack of compliance with the current whale watching regulations was observed. Additionally, individual blow rate variance was correlated with percentage of exposure to boats (0.73, p<0.05). Although humpback whales do not have a critical conservation status, their intrinsic behaviour makes them a major target to the industry. A total of 50.4 hours of humpback whale observation was analysed. Whales were exposed to boats, mainly commercial zodiacs, during 78.5% of the observation time. The mean number of boats within a 1 km radius was 1.9 (±2.3, max=22). The cumulative exposure to whale watching can have long-term consequences for whales. Law enforcement and measures to raise awareness and compliance to current regulations are urgently needed. Suggestions to improve the current regulation were provided. The present work presents the first abundance estimates for the study area, refines the available information on baleen whales core areas, provides support to the establishment of an adequate zoning plan within the SSLMP and stresses the relevance of the SLEMPA. In addition it provides an in depth overview of the marine traffic issue and provides valuable information to support management of this complex socio-ecological system. / Thesis written in co-mentorship with Robert Michaud.

As unidades de conservação são componentes essenciais para a proteção da biodiversidade, e desempenham um importante papel para o bem-estar da sociedade. Contudo, somente a criação de unidades de conservação não é suficiente para assegurar este patrimônio natural, sendo necessária uma gestão eficaz para o cumprimento dos objetivos de cada UC. O uso de ferramentas de avaliação é essencial em qualquer processo de gestão, a fim de apontar as fragilidades e pontos fortes do manejo que vem sendo realizado, de forma a corrigir rumos e estabelecer novas metas. Áreas de proteção marinhas são essenciais para a manutenção dos recursos marinhos regionais, como a pesca, pela proteção de áreas reprodutivas; para a proteção de habitats vulneráveis e espécies ameaçadas; para a redução do impacto do turismo e outras atividades humanas, e por serem aliadas na mitigação e adaptação às mudanças climáticas. O Brasil possui, considerando as reentrâncias, mais de 8500 km de linha de costa e, apesar da importância econômica, ecológica e social de áreas marinhas, apenas cerca de 1,5% desse território é protegido. Além disso, as poucas unidades existentes são carentes de condições e infraestrutura para fiscalização, monitoramento e outras atividades visando sua efetiva implantação. Esta pesquisa teve como objetivo avaliar a efetividade da gestão ambiental em três unidades de conservação marinhas de proteção integral no litoral de São Paulo (Estação Ecológica dos Tupiniquins, Estação Ecológica de Tupinambás e Parque Estadual Marinho da Laje de Santos) através de metodologia semi-quantitativa baseada em Faria (2004), que propõe a análise das condições de manejo existentes em diversos âmbitos organizados numa matriz de cenário. A metodologia sofreu algumas modificações para atender às peculiaridades de unidades de conservação marinhas. As pontuações atingiram 68% (Estação Ecológica Tupiniquins), 70% (Estação Ecológica Tupinambás) e 71% (Laje de Santos Parque Estadual Marinho) de eficácia de gestão. Os principais fatores que comprometem o pleno cumprimento dos objetivos das áreas estudadas são a falta de integração entre gestão costeira e setores econômicos, baixos recursos financeiros, planejamento inadequado das unidades na época da criação, falta de um diagnóstico ambiental inicial completo e mesmo posterior, no incentivo de parcerias para pesquisas permanentes. Além disso, se discute neste estudo a eficiência da própria metodologia utilizada em se atingir uma análise realista sobre o estado de gestão das unidades. / Protected areas are essential components for biodiversity protection and society welfare. To achieve the goals proposed by the creation of a protected area it is necessary to have a planning adapted to the reality of local conditions and an efficient management based on this planning what frequently is not the case due to several factors. The use of assessment tools is fundamental to every management process aiming to point fragilities and strengths. Marine protected areas (MPAs) are important for the maintenance of regional marine resources such as fisheries, the protection of reproductive areas, the protection of vulnerable habitats and endangered species, to reduce the impact of tourism and other human activities, and for being allied in mitigation and adaptation to climate change. Brazil has approximately 8500 km of coastline and, despite the economic, ecological and social importance of marine areas, only about 1.5 % of the territory is protected. The few existing units are lacking in infrastructure and conditions for supervisory monitoring and other activities aiming its effective implementation. This research aimed to evaluate the effectiveness of environmental conservation in three marine protected areas on the coast of São Paulo. For this, we used a semi-quantitative methodology based on Faria (2004), that uses a selection of indicators organized into scenery matrix and associated with a standard score. The methodology was modified to suit the peculiarities of marine protected areas. The scores attained effectiveness of 68% (Tupiniquins Ecological Station), 70% (Tupinambás Ecological Station) and 71% (Laje de Santos Marine State Park). The main common factors that compromise the complete fulfillment of the objectives of the studied areas are the lack of integration of the coastal management with other economic sectors and low government resources allocated to the protected areas. Moreover, it discuss about the efficiency of the used methodology to analyze the units management status.

Species conservation is typically founded upon a range of management strategies, which integrate both biological and socioeconomic data. In this thesis, population genetics, acoustic telemetry, spawning aggregation surveys and stakeholder assessments were used to address key knowledge gaps limiting effective conservation management for critically endangered Nassau grouper (Epinephelus striatus) stocks in The Bahamas. A panel of polymorphic microsatellite markers was optimised to assess the genetic population dynamics of more than 400 Nassau grouper sampled throughout the country. Microsatellite data indicate that contemporary Nassau grouper populations in The Bahamas are predominantly genetically diverse and weakly differentiated, but lack geographic population structure. Assessments of changes in effective population size (Ne) show substantive reductions in Ne within The Bahamas compared to historic values that are likely due to natural disturbances. Evidence for recent bottlenecks occurring in three islands as well as an active spawning site, along with higher inbreeding coefficients in two islands were also found, and can be attributed to more recent anthropogenic activities. Collapse of a historically important Nassau grouper fish spawning aggregation (FSA) was supported by both acoustic telemetry and spawning aggregation survey dives. Restriction-site-associated DNA sequencing (RAD-seq) of 94 Nassau grouper was used to explore intraspecific population dynamics, loci under selection and patterns of gene flow in The Bahamas. Genomic assessments of diversity were in accord with microsatellite data and examinations of gene flow support higher levels of connectivity in The Bahamas than was previously suggested. The increased resolution gained from assessments of genomic data support intraspecific population structuring that may be driven by differences in gene flow and putative loci under divergent selection. Telemetry data were successfully used to identify the origins of spawning adults, and support demographic connectivity through migrations between an active FSA in the central Bahamas and home reef habitats within the Exumas and a no-take marine protected area. Stakeholder assessments highlight the complexities of fisheries management within The Bahamas, with key stakeholders often exhibiting conflicting opinions regarding the status of Nassau grouper and the efficacy of management options. However, these groups mutually agree upon the need to better manage remaining Nassau grouper stocks within The Bahamas through science-grounded policies. Synthesis of these studies along with a review of fisheries governance in The Bahamas was used to develop a comprehensive national management plan for Nassau grouper to facilitate better conservation for remaining populations of this ecologically important marine species.

En esta tesis se aborda la cuantificación, mediante censos visuales, de las pautas de variación espacial y temporal de los poblamientos de peces que viven en los fondos rocosos infralitorales del Mediterráneo occidental, a varias escalas espaciales, y se estima la importancia relativa de la estructura del hábitat rocoso para explicar dichas variaciones. En sucesivos estudios, utilizándose técnicas de análisis espacial, se muestra que riqueza, abundancia y diversidad de peces responden a las variaciones del hábitat estructural (distinguiéndose entre complejidad y heterogeneidad), tanto a escala local como a múltiples escalas espaciales jerarquizadas. Por otra parte, el poblamiento de peces muestra una notable estabilidad temporal, aunque ésta depende de las escalas taxonómica, espacial o analítica considerada, pudiendo esta estabilidad ser debida al efecto del hábitat sobre las poblaciones. La influencia de la estructura del hábitat rocoso puede enmascarar, e incluso contrarrestar, los beneficios esperados de la protección pesquera.

Marine protected areas (MPAs) may be implemented as a means of managing human impacts on the marine environment; however, MPAs commonly have both biological and social goals, which are often addressed through the use of multiple use marine zoning. In British Columbia, 900 km2 of the waters surrounding the southern Gulf Islands are under consideration for a National Marine Conservation Area (NMCA). Should the NMCA be created, a marine zoning plan will be developed for the region. Research has shown that MPAs and associated zoning schemes are unlikely to be successful at meeting their conservation objectives if they are not accepted by, and responsive to the needs of, stakeholders. This study examines recreational boating in the southern Gulf Islands, within the context of the proposed NMCA. Specific areas of focus include: (1) activities, setting preferences, and sources of perceived conflict amongst boaters, (2) dimensions of support for and opposition to the concept of marine zoning amongst boaters, and (3) spatial patterns of recreational boating in the region. Methods included a focus group and a face-to face questionnaire, delivered to boaters in the southern Gulf Islands from June – September, 2007 (n=543, response rate=92%). Results show that there is variability in the environmental, social, and managerial setting preferences of recreational boaters, and that boat type has an influence across all three categories. Furthermore, several activities emerged as sources of perceived conflict for recreational boaters. Reasons provided as to the nature of these conflicts indicate that while some may be potentially addressed through marine zoning, others may be better mitigated through education and communication strategies. While a majority of boaters are supportive of the general concept of marine zoning, there are some issues and concerns that will need to be addressed as MPA implementation proceeds. Support for marine zoning was found to be strongly related to perceived benefits, particularly environmental benefits. Major dimensions of opposition included perceptions of over-regulation, fears of losing access for boating, and mistrust of government involvement in managing the marine environment. Spatial data was collected by asking respondents to indicate on a map the route of their current boating trip, resulting in a rich spatial dataset for recreational boating in the region. Mapping and display of this data indicates both hotspot destinations and heavily traveled corridors for recreational boating; furthermore, because spatial data can be linked to questionnaire variables, this dataset can provide the basis for a great deal of customized mapping and analysis related to spatial patterns of boating. Given that little information on recreational boating in the region existed prior to this study, results from all three areas of focus together make a significant contribution to understanding recreational boating in the southern Gulf Islands, and provides valuable information for MPA planners and managers. In addition, this study also contributes to MPA research, recreation and leisure research, and research examining methods of spatially characterizing boating activity.

Une perte des forêts marines de grandes algues brunes a été observée dans les récentes décennies, causant un changement des écosystèmes et une réduction de la biodiversité. Dans le cadre du projet MMMPA, ce travail de thèse vise à répondre à certaines importantes questions liées à la conservation et à la restauration des forêts d'algues, au rôle des Aires Marines Protégées (AMPs) et les poissons herbivores. Les résultats des expériences sur le terrain ont montré que les poissons herbivores indigènes, probablement Salpa Sarpa (saupes), peuvent être les herbivores les plus efficace des ceintures intertidales de Cystoseira. En effet, les saupes affectent fortement la croissance, la biomasse et la reproduction des forêts naturelles et limitent le succès de la restauration sur des substrats artificiels. Le rôle des poissons herbivores a probablement été négligé dans la régulation des communautés macroalgales Méditerranéennes. Une revue de la littérature existante a montré une amélioration de l'intérêt scientifique (articles publiés) sur les espèces formant les forêts marines, au cours des dernières décennies. Cependant, la plupart de la recherche scientifique n’est pas en relation avec les AMPs, probablement parce que les forêts marines ne sont pas toujours considérées pendant la création des AMPs et dans les plans de gestion. Les études sur les forêts marines étant concentrée dans les pays développés, elles ne sont pas réparties de manière homogène dans le monde. / Loss of marine forests of large brown seaweeds has been observed in recent decades, causing a reduction of ecosystem biodiversity. In the framework of the MMMPA project, this PhD aimed to address some important topics related to the conservation and restoration of algal forests, the role of Marine Protected Areas (MPAs) and fish herbivory. Different approaches were used: macroalgae surveys, literature reviews, manipulative experiments, tank-based experiments and GIS habitat mapping. Results from field experiments showed that native herbivorous fish, likely Sarpa salpa (salemas), can be the most effective herbivore of intertidal Cystoseira belts both on natural and artificial substrates. Indeed, salemas strongly affected the growth, biomass and reproductive output of natural forests and limited restoration success on artificial substrates. Likely, the role of the herbivorous fish in structuring macroalgal communities has been overlooked in the Mediterranean Sea so far. A review of the existing literature showed that knowledge on marine forests forming species has improved in recent decades. However, most of the research is not in relation to MPAs, likely due to the fact that marine forests are not always included in MPAs planning and management plans. Studies on marine forests are not homogeneously distributed in the world, being concentrated in the developed countries. Interestingly, an increase of the scientific interest (published papers) was observed. Nowadays, marine forests are under continuous threats and especially sensitive to multiple impacts.

As unidades de conservação são componentes essenciais para a proteção da biodiversidade, e desempenham um importante papel para o bem-estar da sociedade. Contudo, somente a criação de unidades de conservação não é suficiente para assegurar este patrimônio natural, sendo necessária uma gestão eficaz para o cumprimento dos objetivos de cada UC. O uso de ferramentas de avaliação é essencial em qualquer processo de gestão, a fim de apontar as fragilidades e pontos fortes do manejo que vem sendo realizado, de forma a corrigir rumos e estabelecer novas metas. Áreas de proteção marinhas são essenciais para a manutenção dos recursos marinhos regionais, como a pesca, pela proteção de áreas reprodutivas; para a proteção de habitats vulneráveis e espécies ameaçadas; para a redução do impacto do turismo e outras atividades humanas, e por serem aliadas na mitigação e adaptação às mudanças climáticas. O Brasil possui, considerando as reentrâncias, mais de 8500 km de linha de costa e, apesar da importância econômica, ecológica e social de áreas marinhas, apenas cerca de 1,5% desse território é protegido. Além disso, as poucas unidades existentes são carentes de condições e infraestrutura para fiscalização, monitoramento e outras atividades visando sua efetiva implantação. Esta pesquisa teve como objetivo avaliar a efetividade da gestão ambiental em três unidades de conservação marinhas de proteção integral no litoral de São Paulo (Estação Ecológica dos Tupiniquins, Estação Ecológica de Tupinambás e Parque Estadual Marinho da Laje de Santos) através de metodologia semi-quantitativa baseada em Faria (2004), que propõe a análise das condições de manejo existentes em diversos âmbitos organizados numa matriz de cenário. A metodologia sofreu algumas modificações para atender às peculiaridades de unidades de conservação marinhas. As pontuações atingiram 68% (Estação Ecológica Tupiniquins), 70% (Estação Ecológica Tupinambás) e 71% (Laje de Santos Parque Estadual Marinho) de eficácia de gestão. Os principais fatores que comprometem o pleno cumprimento dos objetivos das áreas estudadas são a falta de integração entre gestão costeira e setores econômicos, baixos recursos financeiros, planejamento inadequado das unidades na época da criação, falta de um diagnóstico ambiental inicial completo e mesmo posterior, no incentivo de parcerias para pesquisas permanentes. Além disso, se discute neste estudo a eficiência da própria metodologia utilizada em se atingir uma análise realista sobre o estado de gestão das unidades. / Protected areas are essential components for biodiversity protection and society welfare. To achieve the goals proposed by the creation of a protected area it is necessary to have a planning adapted to the reality of local conditions and an efficient management based on this planning what frequently is not the case due to several factors. The use of assessment tools is fundamental to every management process aiming to point fragilities and strengths. Marine protected areas (MPAs) are important for the maintenance of regional marine resources such as fisheries, the protection of reproductive areas, the protection of vulnerable habitats and endangered species, to reduce the impact of tourism and other human activities, and for being allied in mitigation and adaptation to climate change. Brazil has approximately 8500 km of coastline and, despite the economic, ecological and social importance of marine areas, only about 1.5 % of the territory is protected. The few existing units are lacking in infrastructure and conditions for supervisory monitoring and other activities aiming its effective implementation. This research aimed to evaluate the effectiveness of environmental conservation in three marine protected areas on the coast of São Paulo. For this, we used a semi-quantitative methodology based on Faria (2004), that uses a selection of indicators organized into scenery matrix and associated with a standard score. The methodology was modified to suit the peculiarities of marine protected areas. The scores attained effectiveness of 68% (Tupiniquins Ecological Station), 70% (Tupinambás Ecological Station) and 71% (Laje de Santos Marine State Park). The main common factors that compromise the complete fulfillment of the objectives of the studied areas are the lack of integration of the coastal management with other economic sectors and low government resources allocated to the protected areas. Moreover, it discuss about the efficiency of the used methodology to analyze the units management status.

L'impact anthropique sur les écosystèmes coralliens est aujourd'hui largement documenté, que ce soit sur la biodiversité qu'ils hébergent, leur diversité fonctionnelle, les services écosystémiques qu'ils procurent ou leur capacité de résilience. Parmi les groupes trophiques, les prédateurs apicaux en général et les requins en particulier, sont particulièrement sensibles aux perturbations d’origine humaine du fait de leurs traits d'histoire de vie conservateurs (e.g. croissance lente, maturité sexuelle tardive, faible fécondité). D'après certaines estimations, les populations de requins ont décliné de plus de 90% à l'échelle globale. Afin d'assurer le maintien de leurs populations et de leur rôle fonctionnel dans la communauté, il est nécessaire de mettre en place des mesures de gestion adaptées. Les objectifs de cette thèse sont de 1) faire le bilan des populations de requins de Nouvelle-Calédonie ; 2) déterminer l'efficacité des vidéos stéréoscopiques appâtées (S-BRUVS) pour recenser les requins en les comparant aux comptages en plongées (UVC) et évaluer leur possible amélioration ; 3) évaluer l'impact de la proximité humaine sur la diversité, l'abondance et le comportement des requins récifaux et 4) déterminer l'efficacité des mesures de gestion en place pour protéger ces espèces emblématiques. Les résultats des deux méthodes de recensement montrent un important déclin d'environ 90% des abondances de requins récifaux le long d'un gradient anthropique complet en Nouvelle-Calédonie alors que la pêche des requins est historiquement absente dans cet archipel. Une importante altération comportementale du requin gris de récif (Carcharhinus amblyrhynchos) face à la nouveauté d'un appât a été mise en évidence. Les individus se tiennent plus éloigné du dispositif, interagissent moins avec l'appât et mettent plus de temps pour le mordre avec l'augmentation de la proximité humaine. Cette dernière est le principal moteur de ce déclin d’abondance (46 à 71%) et de l'altération comportementale vers des individus plus craintifs (50 à 80%). Globalement, les aires marines protégées de Nouvelle-Calédonie ne sont pas efficaces pour la protection des requins. Néanmoins, la réserve intégrale Merlet héberge des populations de requins proche du niveau de récifs isolés de l’archipel et protège une partie du comportement. Les résultats de ce travail révèlent 1) l'importance et le caractère unique des récifs coralliens isolés ; 2) qu'en absence de pêche la proximité humaine conditionne l'abondance et le comportement des requins de récifs avec des conséquences écologiques potentielles sur l'ensemble du réseau trophique ; 3) que l'efficacité des AMPs réside dans leur capacité à exclure la présence humaine sur une surface suffisamment grande. / Anthropogenic impacts on coral reefs are largely documented through changes in functional diversity, ecosystem services or resilience. Among trophic groups, apex predators in general and sharks in particular are the most sensitive to disturbance due to conservative life history traits (e.g. slow growth, late sexual maturity, low fecundity). By some estimates, shark populations have declined by >90% worldwide. To ensure the sustainability of their populations and their functional role in the reef community, appropriate management measures must be implemented. The aims of this thesis are 1) to assess reef shark populations in New Caledonia; 2) to evaluate the efficiency of stereo baited remote underwater video systems (S-BRUVS) in surveying shark distribution comparing them to underwater visual censuses (UVC) and to evaluate their potential improvements ; 3) to evaluate the impact of human proximity on diversity, abundance and behaviour of reef sharks and 4) to determine the efficiency of management measures currently in place in New Caledonia to protect reef shark populations. The results of S-BRUVS and UVC were congruent and revealed a dramatic decline of shark abundance of ~90% along the anthropogenic gradient in a country where shark fishing is historically absent. An important behavioural alteration of the grey reef shark (Carcharhinus amblyrhynchos) towards bait was highlighted. Individuals remained farther from the device, exhibited more cautious approaches, interacted less with the bait and took longer to bite it as human proximity increased. Human proximity was the main driver of the abundance decline (46 to 71%) and the behavioural alteration towards shier individuals (50 to 80%). Globally, MPAs in New Caledonia are not effective in protecting reef sharks. However, the oldest and most restrictive MPA (Merlet) hosts shark abundance close to that of some remote reefs of the archipelago and partially protect the behaviour of individuals. These results 1) emphasize the unique role of remote coral reefs as the last refuges for sharks ; 2) reveal that in absence of shark fishing, human proximity condition shark abundance and behaviour with potential ecological consequences and 3) indicate that the MPAs efficiency to ensure the protection of reef sharks is effected by their ability to exclude human presence over a sufficiently large area.