Passive acoustic monitoring has been successfully used on many elasmobranch species, but no such study has yet been published for the whale shark (Rhincodon typus). In some ways this is surprising as the known whale shark aggregation sites would seem to be ideal targets for this method. For this dissertation, two acoustic studies were carried out in Saudi Arabia and Tanzania. Each was performed in parallel with visual surveys and the Saudi population was also studied using satellite telemetry. Sighting and acoustic data were compared at both sites, and the results were mixed. The acoustic monitoring largely confirmed the results of visual surveys for the Saudi Arabian sharks, including seasonality, residency and a degree of parity and integration between the sexes that is unique to this site. Satellite tracks of tagged Saudi sharks were used to confirm that some animals migrated away from the aggregation site before returning in subsequent seasons, confirming philopatric behavior in this species. In contrast, the acoustic results in Tanzania demonstrated year-round residency of whale sharks in the area, despite seasonal declines in visually estimated abundance. Seasonal changes in habitat selection render the sharks at this site temporarily cryptic to visual sampling. The differing results are compelling because both the philopatric behavior demonstrated in Saudi Arabia and the cryptic residency of the Tanzanian sharks could explain the seasonal patterns in whale shark abundances reported at other aggregation sites. Despite their differences, both sites in this study can be classified as secondary whale shark nurseries and each may be a vital feeding ground for its respective population.

The conservation status of the widely-distributed whale shark Rhincodon typus is presently listed as 'Indeterminate - Data Deficient'. One of the main hindrances to obtaining biological data on whale sharks that is relevant to determining its 'conservation status' is that this species has rarely been recorded as occurring in sufficient numbers to obtain quantitative data. However, R. typus does form aggregations at Ningaloo Marine Park (NMP), Western Australia, annually between March and June. This has enabled studies to be made of aspects of the biology of R. typus and of the possible impacts of the ecotourism industry on this species. Using a position provided on vessels involved with the whale shark ecotourism industry at NMP, R. typus was observed on 360 separate occasions in 1995, 1996 and 1997, and it was possible to sex 90.3% of these sharks. The majority of the sexed sharks (84.6%) were male and ranged in length from 4 to 12 m, with a mean of 7.4 m, while the females ranged in length from 4.5 to 8.5 m, with a mean of 6.2 m. The size and degree of abrasion of the claspers was used as an indicator of whether or not a male shark had mated. Using such criteria, it was estimated that male whale sharks start to mature at ca 8 m and that ca 50% are mature by the time they reach 8.6m. Observations suggested that R. typus feeds by using both suction and flow-through mechanisms. The prey that were observed being ingested included coral spawn, tropical krill, mysids and small jellyfish. The contents of a faecal sample contained parts of the exoskeleton of copepods and the scales of small fishes. The degree of mouth distension, which is assumed to be related to feeding activity, was low during most observation periods. Photographs of the scars and natural patterning on the skin of individual sharks were used to construct a photographic library for subsequent identification of these sharks. The features used for identifying individual sharks were chosen because they were considered likely to remain for a protracted period. The Whale Shark Photo -identification Library that was produced provides details on the characteristic features of 52 R. typus that were present at NMP. Six individuals were recorded at NMP in both 1995 and 1996, four in both 1996 and 1997, and one in both 1995 and 1997. No identified whale sharks were recorded in all three years. Rhincodon typus was distributed widely throughout NMP, with most boat and aerial sightings lying within 1 - 2 Ism of the reef crest between Tantabiddi and Turquoise Bay. Rhincodon typus was typically sighted in water depths of 10 to 30 m. The sharks were predominantly travelling parallel to Ningaloo Reef, with significantly more moving in a northward than southward direction. Acoustic tracking of R. typus in 1997 suggested that this species remains within NMP for extended periods and is at the surface for ca 17% of daylight hours. The number and species of fauna observed to be associated with R. typus were recorded, and a new species of copepod, Pandarus sp. nov., which lives on the skin of R. typus has been described. Golden trevally (Gnathanodon speciosus), miscellaneous trevally (Carangid sp.), remora (Remora sp.) and slender suckerfish (Echeneis naucrates) were common. The prevalence of Pandarus sp. nov. was inversely proportional to the number of Remora sp. and E. mucrates in 1996, while the opposite was true in 1997, suggesting that Pandarus sp. nov. were preyed on by these diskfish. Rhincodon typus is the basis of the ecotourism industry that operates within NMP each year. While there was considerable variation in the number of tour vessels searching for whale sharks at NMP each year, the greatest mean number of vessels operating per week in successive whale shark seasons were 6.7 during Week 8 (April 19 - 25) of 1995, 6.1 during Week 7 (April 12 - 18) of 1996 and 6.9 during Week 8 (April 19 - 25) of 1997. The greatest mean numbers of whale sharks sighted per week in each year were 5.1 during Week 14 (May 31 - June 6) of 1995,4.2 during Week 6 (April 5 - 11) of 1996 and 4.1 during Week 8 (April 19 - 25) of 1997. Tourists, who were permitted to swim alongside R. tyus, interacted with sharks for a mean period of 19.3 rnin in 1995, 14.2 min in 1996 and 9.5 rnin in 1997. The reduction in the duration of interaction in three successive years suggests that, over time, R. typus may have become slightly less tolerant of the ecotourism industry at NMP. The mean minimum distance between vessel and shark during each interaction was 20.7 m in 1995, 21.3 m in 1996 and 31.0 m in 1997. The mean minimum distance between tourist and shark during each interaction was 1.5 m in 1995, 2.05 m in 1996, and 2.1 m in 1997. The mean minimum distance of vessel and tourist from R. typus during each individual interaction decreased as the duration of the interaction increased. Therefore, both R. typus and this industry must be carefully monitored to ensure that the impacts of humans are kept to a minimum and thereby ensure that whale sharks return to NMP each year. An ethology of whale shark behaviours, which included banking, porpoising, diving and eye-rolling, was produced in an attempt to determine whether there is evidence that the ecotourism industry has a negative impact on R. opus at NMP. The frequency of behavioural change was greatest in the first 0 - 5 min of an observation. Eye-rolling by R. typus was recorded as a reaction to flash-photography, while banking was often recorded when SCUBA was used and/or tourists swam beneath the head of the shark. The swimming speed of R. typus at NMP was rarely too fast for tourists to maintain proximity to the sharks. Several sharks possessed both recent and healed scars, which were probably inflicted by vessel contact. The recent wounds indicate that vessels had caused injuries to R. typus within NMP. These individuals tended to display a higher frequency of avoidance behaviours and reduced interaction times. Recommendations are provided to the Western Australian Department of Conservation and Land Management which are aimed at reducing the potential deleterious effects of the ecotourism industry on the whale sharks at NMP.

Movement and behavior studies are traditional yet effective ways to understand the biology and ecology of a species. For an endangered species like the whale shark (Rhincodon typus), a comprehensive knowledge of its movement and behavior is particularly critical for successful management and conservation. For this dissertation, acoustic telemetry and biologging tagging studies were carried out at a seasonal whale shark aggregation site near Al Lith in the Saudi Arabian Red Sea. Acoustic telemetry data revealed consistent path usage in a narrow longshore area with patterns in seasonality and diel horizontal movements within a smaller scale. Some individuals specifically concentrated on this path and made non-stop back and forth movements along it. In another dimension, depth use of whale sharks derived from biologgers showed distinct diel patterns. The sharks heavily utilized shallow waters with mixed depth usage consisting of surface swimming and varied types of dives, which explained the data of previous visual surveys. Vertical velocities indicated potential energy expenditure strategies that were further investigated based on acceleration data. Energy expenditure data suggested strategies that fine-tuned foraging efforts to optimize the balance between feeding and foraging. However, while these strategies fit well in the natural habitat, local human impacts could be of great disturbance if not well managed.

Sharks are among the most threatened taxonomic groups worldwide. Shark tourism is viewed as a potential means of protecting threatened species, while also providing a sustainable livelihood for local communities. Whale sharks are one such species. Whale shark tourism has grown rapidly in the last twenty years. It is worth an estimated US$66 million and is available in over 15 countries worldwide. However, the management of this industry varies greatly from site to site, from little to no regulations in Thailand to license caps and interaction guidelines in Australia. Further, the long-term sustainability of whale shark tourism is dependent not only on local scale management, but also global scale issues affecting the targeted species. This study assesses the current status and future sustainability of the whale shark tourism industry on Isla Holbox, Mexico. Specific areas of focus include: (1) tourist motivations and satisfaction with the environmental and tour features offered, (2) shark tourist specialization, (3) a comprehensive assessment of the site’s sustainability using Duffus & Dearden’s (1990) Wildlife Tourism Model, and (4) an assessment of the whale sharks’ vulnerability to global scale threats (e.g. marine pollution; global climate change). Methods included a questionnaire provided to whale shark tour participants on Isla Holbox from June to September, 2008 (n=392, response rate=90%), in-water observation of human-whale shark interactions, and the application of a semi-quantitative climate change vulnerability framework. Results suggest that the industry on Holbox is reaching its tipping point if changes are not made to improve its management policies and design. Industry issues include: (1) crowding due to poor control of the industry’s growth (visitation and number of operators), (2) significant impacts on the whale shark population due to poor compliance with interaction guidelines, and (3) the inequitable distribution of benefits within the community, including significant economic leakages. The results of the vulnerability assessment to large-scale threats suggest that global climate change could have a significant impact on the size and distribution of whale shark aggregations in the future. Thus, the majority of whale shark tourism activities, which are based on whale sharks aggregating in vulnerable habitats, may be unsustainable in the long-term regardless of management approach. The type of users and format of tours on Holbox further supports an increased vulnerability to climate change. This study provides a significant contribution to understanding the sustainability of marine wildlife tourism activities targeting threatened species within critical habitats through the assessment of whale shark tourism sustainability using an integrated, multidisciplinary model that addresses both the social and biological dimensions of sustainability. It also includes the first comprehensive assessment of whale shark vulnerability to global climate change based on habitat type and its implications for whale shark tourism activities targeting this species at seasonal aggregation sites. In addition, this study also provides a greater understanding of tourist motivation and satisfaction within marine wildlife tourism, and shark tourism in particular and a first look at shark tourist specialization and its links to environmental impacts and management preferences.

Wildlife tourism is promoted as a livelihood alternative activity to extractiveuse, such as the case of whale shark interaction in Quintana Roo, Mexico. Whale sharksseasonally aggregate (from May to September) northeast Yucatan peninsula, where theyannually attract about 20000 visitors.This study analyzes the socio-economic drivers, influencing the sustainability of thisrecreational activity, through semi-structured (n=44) and in-depth (n=4) interviews tolocal stakeholders, tourists surveys (n=262), and a cost-benefit analysis.Results indicate that intermediaries put pressure on the optimization of the operation, aswell as it decreases the economic return to local operators (licensees). Local operatorsare not aware of the real costs of operations, and additionally tourists are poorlyinformed of (1) the species, (2) the code of conduct (regulations) and (3) how to supportlocal community’s development. In conclusion, those factors along with the lack ofsurveillance threaten whale shark tourism sustainability. Inclusion of all stakeholders inmanagement and planning of wildlife tourism is necessary in order to obtain desirablepractices, as well as investment in environmental education.

In 1938 Dr. Eugene Gudger concluded of the Red Sea that "whale sharks must surely abound in this region." Seventy years later, multi-method research began on a whale shark (Rhincodon typus) aggregation at Shib Habil, a reef near Al Lith, Saudi Arabia. However, in 2017 and 2018, a dramatic decline in encounters at this site drew questions about the aggregation's future and overall whale shark population trends in the region. In this dissertation, I describe and discuss the two-year decline in encounters and show that neither remotely sensed sea surface temperature nor chlorophyll-a concentrations were significantly different in seasons with or without sharks. Citizen science-based photo identification was used to characterize the northern Red Sea population, the Red Sea population as a whole, show limited crossover within the basin, and connections with another aggregation in Djibouti. Scarring rates within the Red Sea are compared to recent global studies, and the Red Sea uniquely had no predator bites observed, suggesting boat collisions are likely the leading cause of major scars. Finally, building upon previous genetic work comparing Red Sea and Tanzanian sharks using microsatellites, the mitochondrial control region was sequenced, and two global haplotype networks were produced and compared to each other and previous work. The stability of genetic diversity within the Shib Habil aggregation is compared to declines previously measured in Australia. As tourism develops along the northern Saudi Arabian coast and citizen science increases in the Red Sea, population dynamics within the region could be better understood. The genetic connectivity of Red Sea whale sharks to the Indo-Pacific population exemplifies the need for continued collaborative research beyond local aggregations and multinational conservation measures.

Motivation behind the spring whale shark (Rhincodon typus) aggregation in Al-Lith, on the Saudi Arabian coast of the South Central Red Sea, is uncertain. A plausible hypothesis is that whale sharks gather to feed on high prey density, leading to questions about the cause of the prey density. A bottom-up process fueled by nutrient input or accumulation from physical advection could create a peak in prey biomass. Wastewater discharged from an aquaculture facility could affect productivity or provide a chemosensory cue for whale sharks. Yet, basic physico-biological oceanography of this region is unresolved. Monthly profiles, long-term moorings, and spatial surveys were used to describe the temporal variability of potential prey biomass and water masses in this region for the first time. Plankton abundance of individuals larger than ~0.7 cm did not peak during whale shark season. Rather, a decrease coinciding the trailing end of whale shark detections was observed. Sites 180 m apart had differences in acoustic backscatter, suggesting small-scale biomass patchiness, supporting the small-scale variability in whale shark habitat selectivity. Red Sea Deep Water, a nutrient-rich water mass formed in the northern Red Sea, appeared in July at the same time the Tokar wind jet from the Sudanese mountain gap is the highest. Gulf of Aden Water, a nutrient-rich water mass from the Indian Ocean, arrived as episodes from May to September, contrary to previous expectations that the water arrives continuously. It is unlikely that these natural nutrient sources are directly responsible for the high prey density attracting the whale sharks. The aquaculture plume, observed at the aggregation site, had a distinct seasonality from the ambient waters. The plume’s highest salinity (>48) approached the extreme limits of coral tolerances. Nutrient concentrations (nitrate, nitrite, phosphate, silica), suspended particulate matter, phytoplankton biomass, bacteria and cyanobacteria cell counts, total nitrogen, and relative abundance of genera associated with opportunistic pathogenic species (e.g., Arcobacter) were significantly higher in the plume. This study was the first to estimate the nutrient flux and spatial variability of the aquaculture plume.

Dans le cadre de l’Approche Ecosystémique des Pêches (AEP), il est nécessaire d’évaluer l’impact de la pêche thonière tropicale à la senne sur les espèces ciblées et sur les espèces accessoires. Parmi ces dernières, les espèces de la mégafaune, telles que des requins, raies, cétacés, tortues, oiseaux marins, sont souvent emblématiques et vulnérables. Les thoniers senneurs tropicaux recherchent activement à la surface de l’eau tout indice de la présence de bancs de thon (e.g. oiseaux, objets flottants, baleines, dauphins ou requins baleines). Dans l’est de l’océan Atlantique et l’ouest de l’océan Indien, les deux modes de pêches principaux sont les captures de thons en bancs libres et celles sur bancs associés à un objet flottant, naturel ou artificiel, rassemblés ici sur sous le terme de dispositif de concentration de poisson (DCP). Les calées associées aux requins baleines et aux cétacés sont toutefois peu étudiées. L’objectif de cette thèse est donc d’analyser les co-occurrences et/ou interactions spatio-temporelles entre requins baleines, cétacés et pêche thonière à la senne, dans une perspective de conservation de l’écosystème. Ce travail, basé sur des données de livres de bord et d’observateurs scientifiques embarqués, a montré que la co-occurrence pêche thonière/ mégafaune se localise dans des strates spatio-temporelles relativement précises: i) du Gabon à l’Angola (avril–septembre), ii) dans le Canal du Mozambique (juin–septembre) et iii) à l’est des Seychelles (avril–septembre). Les baleines et requins baleines étant planctivores, la co-occurrence avec la pêche à la senne est principalement liée à une forte productivité primaire (appréhendée à travers des proxys tels que la concentration en chlorophylle-a). De plus, les calées sur ces deux groupes étaient assez élevées avant 2000 (jusqu’à 20% des calées), et qu’elles sont moins fréquentes aujourd’hui (AC3 et 1,5% des calées associées à des baleines et des requins baleines, respectivement). L’impact de la pêche à la senne sur ces espèces semble relativement faible au regard du taux de mortalité apparente de 1,4% pour les requins baleines et 5,6% pour les cétacés. Des marquages satellites réalisés sur les requins baleines, confirment ces observations sur le plus long terme, mais la taille de l’échantillon limite la formulation de conclusions définitives. Concernant les dauphins, bien que présents sur les zones de pêche, ils interagissent très peu avec celle-ci, soulignant ainsi une différence majeure avec l’océan Pacifique est où ce mode de pêche est majoritaire. La diversité spécifique des espèces cible et accessoire associées aux calées sur mégafaune a également été étudiée. Les requins baleines sont associés aux listaos et à l’albacore (dans une large gamme de tailles), alors que les baleines le sont principalement à de gros albacores. De plus, la capture accessoire associée à ces deux groupes de mégafaune est relativement faible et dominée par le requin soyeux et la diversité spécifique est proche de celle trouvée sous les bancs libres de thons. Enfin les effets de mesures de conservation vis-à-vis de la mégafaune encerclée ou de mesures de gestion de l’effort de pêche, notamment les moratoires sur DCP réelles ou simulées (e.g. moratoires élargis), ont été analysés. Les premières ont eu un effet limité en terme de captures cibles et accessoires, alors que les moratoires impactent peu le nombre de calées associés à la mégafaune, ceci en raison du décalage spatio-temporel des co-occurrences. Cependant des moratoires élargis pourraient être bénéfiques pour les thons juvéniles et certaines espèces associées. Par l’analyse quantitative des interactions entre la pêche thonière à la senne et la mégafaune, cette thèse apporte des connaissances essentielles sur les espèces étudiées dans le cadre de la mise en place d’une AEP, applicable à la pêche thonière tropicale. / In the frame of the Ecosystem Approach to Fishery (EAF) management, impact of the tropical tuna purse-seine fishery on targeted and incidentally captured species should be investigated. They may include megafauna species, such as sharks, rays, cetaceans, turtles or sea birds, which often are emblematic and vulnerable species. Tropical tuna purse-seiners actively search, at the surface of the sea, for clues indicating the presence of tuna schools (e.g. birds, floating objects, whales, dolphins or whale sharks). In the eastern Atlantic and western Indian Oceans, the main two fishing modes are sets on free swimming tuna schools and schools associated to natural or artificial floating objects, thereafter called Fish Aggregating Device (FAD). However dedicated studies on fishing sets associated to whale sharks and cetaceans are still lacking. The aim of this thesis is therefore, using logbook and scientific onboard observer data, to investigate the spatio-temporal co-occurrences and/or interactions between whale sharks, cetaceans and the tuna purse-seine fishery within an ecosystem conservation perspective. This work underlines that the megafauna/ fishery co-occurrence occurs in specific spatio-temporal strata: i) Gabon to Angola (April–September), ii) the Mozambique Channel (June–September), and iii) East of Seychelles (April–September). As baleen whales and whale sharks are filter feeders, the co-occurrence with the purse-seine fishery was mostly linked to highly productive environments (i.e. using proxys including chlorophyll-a concentration). In addition fishing sets involving megafauna were relatively high before 2000 (up to 20% of the sets), but are nowadays less frequent (AC3 and 1.5% of the sets associated to baleen whales and whale sharks). The purse-seine fishery appears to have a relatively low impact on megafauna species with mortality rates of 1.4% for whale sharks and 5.6% for cetaceans. Whale shark satellite tagging also confirms these results on the longer term, but the low sample size precludes any final conclusion. While dolphins are present in fishing areas, very few interactions with the fishery was detected, which highlights the striking difference with the eastern Pacific Ocean where half the sets are associated to dolphin herds. In addition, the diversity of targeted and bycatch species captured under whale shark and baleen whale sets was also investigated. Whale sharks are principally associated to skipjack and yellowfin (of various sizes) tunas and baleen whales mostly to large yellowfin tuna. In addition, bycatch species associated to these two megafauna groups was relatively low and dominated by the silky shark, and bycatch diversity was close to the one found for free swimming tuna schools. Finally, real and/or simulated encircled megafauna conservation measures or fishing effort management measures (especially FAD moratoria including larger ones) were investigated. The first ones were found to have limited consequences on tuna catch and bycatch. Conversely FAD moratoria had limited impacts on the number of megafauna associated fishing sets, due to the fact that the main spatio-temporal strata of megafauna and FAD sets differ. However larger and longer moratoria could be beneficial for juvenile tuna and some bycatch species. Overall, this thesis has lead to increase the knowledge on megafauna/ fishery interactions, essential in the general framework of setting up an EAF in the tropical tune purse-seine fishery.

Biodiversity loss is one of the major environmental threats facing the planet. Incentive-based conservation is one means to reduce human pressure on wildlife by providing economic incentives for resource-dependent people to protect the environment. Marine wildlife tourism is one of the fastest growing tourism sectors globally and is viewed as an important incentive-based approach for achieving marine conservation goals. However, few studies have linked participation in the provisioning of marine wildlife tourism activities with positive social and ecological conservation outcomes. The goal of this dissertation is to provide greater understanding of the conservation value of marine wildlife tourism using whale shark tourism as a case study with a main focus on social conservation outcomes amongst tourism providers. Positive changes in perceptions, attitudes and values towards target species and their environments can be an important element of incentive-based conservation. The study has the following objectives: (1) to assess the status of the global whale shark tourism industry, including types (e.g., captive, non-captive), real and potential impacts, conservation value and management challenges and best practices; (2) to examine the ethics of provisioning whale sharks in Oslob, Philippines, the largest, non-captive viewing site in the world; (3) to determine if working in ecotourism changed the attitudes and behaviours of locals towards whale sharks and the ocean, and if tourism type affects those outcomes; (4) to assess the marine wildlife value orientations of locals working in whale shark tourism to achieve greater understanding of the factors influencing their conservation attitudes and behaviours; (5) to explore the potential long-term impacts of poorly conceived incentive-based conservation projects on social and ecological conservation outcomes; and (6) to re-examine and update the conceptual and theoretical background for wildlife tourism in light of the findings of this study. Methods include a comprehensive literature review, tourist surveys, social media content analysis, and interviews with locals working in whale shark tourism at four sites in the Philippines. Results suggest that marine wildlife tourism can play an important role in changing locals’ attitudes and behaviours towards the focal species and habitat; however, smaller-scale, more established sites had greater conservation value than the mass tourism or failed sites suggesting that small-scale, community-based ecotourism is the best approach to meeting conservation goals of marine wildlife tourism. Yet, few tourism sites meet these standards. Global standards are needed to ensure whale shark tourism activities meet desired conservation goals. Such standards should include management requirements (e.g., licensing, mandatory education program) and interaction guidelines (e.g. minimum viewing distances, limits on the number of swimmers/boats, etc.). The findings also emphasise that economics should not be the only or primary metric used to measure conservation success; rather, the focus should be on assessing a more comprehensive range of social and ecological conservation outcomes of these activities. / Graduate / 2020-04-16