Distribution and group structure of bottlenose dolphin (Tursiops truncatus) in the east of Aegean Sea / Claire Massin

Public ISBD Titre : Distribution and group structure of bottlenose dolphin (Tursiops truncatus) in the east of Aegean Sea Type de document : TFE / Mémoire Auteurs : Claire Massin, Auteur ; Gaëtane Maernoudt, Directeur de publication, rédacteur en chef Editeur : Montignies-sur-Sambre : Helha. Agronomie Année de publication : 2023 Note générale : Le fichier numérique de ce document est disponible uniquement pour les membres de la Haute Ecole Louvain-en-Hainaut ainsi que ses étudiants. Veuillez-vous connecter pour accéder à votre compte lecteur Langues : Français (fre) Index. décimale : TFE AIBT TFE Agro-industries et biotechnologies Résumé : Conclusion The bottlenose dolphin has been classified as vulnerable by the IUCN since 2010 (Accobams, 2021). This dissertation exists to halt the evolution of threats to this dolphin and initiate appropriate conservation actions. To measure the impact of human activity on Tursiops truncatus, we decided to study this species from a specific angle: distribution and group structure in the Aegean Sea. These indicators will enable us to easily see if the impact has already taken its toll, and can also serve as a reference for future studies. The main objectives of this dissertation were to characterize and determine the distribution. We know that there are two different types of lifestyles adopted by these dolphins (Bearzi, G., 2009): - Coastal environment - Pelagic environment As a result, we found that the majority of dolphins live close to the coast. We have confirmed that the dolphins observed were mostly faithful to their environment. And we hypothesized that the strong presence of dolphins in the D,E,F regions was probably due to the heavy presence of fishing boats. This could be explained by the opportunistic regime (Blanco, C., Salomón, O., & Raga, J. A., 2001). . As we look to the future, we need to protect the coasts to maintain a habitat favorable to the life of these dolphins. Also, raise awareness among local people and seafarers to avoid accidental catches. The second aim was to map the distribution and characterize the group structure of bottlenose dolphins. We had two hypotheses concerning this aspect. The first was to have well-distanced groups with very strong associations between individuals (Pleslić, G. et al., 2019). The second was, on the contrary, to have a large group with many associations but no strong links in particular. It was also shown that they formed groups, sometimes small, sometimes large, with a strong bond between all the dolphins. This is very characteristic of the fission-fusion tendency very present in this species (Danaher-Garcia, N., Connor., 2022). We also found that, contrary to expectations, the population is not divided into distinct groups. It would be interesting to look into this for future studies. Indeed, this anomaly could be a consequence of human activity in this region. The abundance of marine traffic could disrupt communication between individuals, preventing the formation of groups with a particular affinity The final aim of the study was to collect data to monitor the evolution of human impact on this species, but also because there is a cruel lack of data concerning this geographical area. Few studies have been carried out on the distribution and group structure of bottlenose dolphins in the Aegean Sea. To conclude this dissertation, it is fair to say that the results obtained from this dissertation correlate with the hoped-for results. So, we need to continue the research about this species to fill data gaps. To do this, we would need to vary the locations of boat surveys and verify the abundance of the population in the north of the island. Another idea is to add the variables age and sex to the boat observations. We know that group formation is strongly influenced by these two criteria. Note de contenu : Table des matières ACKNOWLEDGMENTS ................................................................................................................................................ 3 INTERNSHIP SITE........................................................................................................................................................ 4 INTRODUCTION ........................................................................................................................................................... 6 1. GENERAL CONTEXT .......................................................................................................................................... 7 1.1 SPECIES .................................................................................................................................................................................... 7 1.2 DIET ......................................................................................................................................................................................... 8 1.3 BEHAVIOR ................................................................................................................................................................................ 9 1.4 GEOGRAPHIC AREA ............................................................................................................................................................... 12 1.5 ANTHROPIC THREATS .......................................................................................................................................................... 16 1.6 IUCN ..................................................................................................................................................................................... 20 1.7 REGULATIONS ....................................................................................................................................................................... 20 1.8 PRESERVATION ACTION ....................................................................................................................................................... 21 .......................................................................................................................................................................................22 2. OBJECTIVE AND STRATEGY .........................................................................................................................23 3. MATERIALS AND METHODS .........................................................................................................................24 3.1 STUDY AREA .......................................................................................................................................................................... 24 ...................................................................................................................................................................................................... 27 3.2 BOAT-BASED SURVEYS ......................................................................................................................................................... 29 3.3 PHOTO-ID DATA COLLECTION AND ANALYSIS .................................................................................................................... 30 3.4 STATISTICS TEST .................................................................................................................................................................. 32 4. RESULTS ............................................................................................................................................................34 4.1 PHOTO-ID METHOD ............................................................................................................................................................. 34 4.2 GROUP ASSOCIATION AND DISTRIBUTION........................................................................................................................... 34 4.3 POPULATION ABUNDANCE ................................................................................................................................................... 38 4.4 MOVEMENTS BETWEEN AREAS ........................................................................................................................................... 39 4.5 ANTHROPIC THREATS .......................................................................................................................................................... 41 5. DISCUSSION ......................................................................................................................................................43 5.1 GROUP ASSOCIATION AND DISTRIBUTION........................................................................................................................... 43 5.2 ABUNDANCE ......................................................................................................................................................................... 44 5.3 MOVEMENTS BETWEEN AREAS ........................................................................................................................................... 45 5.4 HABITAT ECOLOGY ............................................................................................................................................................... 45 5.5 ANTHROPIC THREATS .......................................................................................................................................................... 45 2 5.6 CONSERVATION ACTION ....................................................................................................................................................... 46 6. CONCLUSION ....................................................................................................................................................47 BIBLIOGRAPHY..........................................................................................................................................................49 GLOSSARY ...................................................................................................................................................................56 APPENDIX ...................................................................................................................................................................57 Permalink : ./index.php?lvl=notice_display&id=113382 Distribution and group structure of bottlenose dolphin (Tursiops truncatus) in the east of Aegean Sea [TFE / Mémoire] / Claire Massin, Auteur ; Gaëtane Maernoudt, Directeur de publication, rédacteur en chef . - Montignies-sur-Sambre : Helha. Agronomie, 2023. Le fichier numérique de ce document est disponible uniquement pour les membres de la Haute Ecole Louvain-en-Hainaut ainsi que ses étudiants. Veuillez-vous connecter pour accéder à votre compte lecteur Langues : Français (fre) Index. décimale : TFE AIBT TFE Agro-industries et biotechnologies Résumé : Conclusion The bottlenose dolphin has been classified as vulnerable by the IUCN since 2010 (Accobams, 2021). This dissertation exists to halt the evolution of threats to this dolphin and initiate appropriate conservation actions. To measure the impact of human activity on Tursiops truncatus, we decided to study this species from a specific angle: distribution and group structure in the Aegean Sea. These indicators will enable us to easily see if the impact has already taken its toll, and can also serve as a reference for future studies. The main objectives of this dissertation were to characterize and determine the distribution. We know that there are two different types of lifestyles adopted by these dolphins (Bearzi, G., 2009): - Coastal environment - Pelagic environment As a result, we found that the majority of dolphins live close to the coast. We have confirmed that the dolphins observed were mostly faithful to their environment. And we hypothesized that the strong presence of dolphins in the D,E,F regions was probably due to the heavy presence of fishing boats. This could be explained by the opportunistic regime (Blanco, C., Salomón, O., & Raga, J. A., 2001). . As we look to the future, we need to protect the coasts to maintain a habitat favorable to the life of these dolphins. Also, raise awareness among local people and seafarers to avoid accidental catches. The second aim was to map the distribution and characterize the group structure of bottlenose dolphins. We had two hypotheses concerning this aspect. The first was to have well-distanced groups with very strong associations between individuals (Pleslić, G. et al., 2019). The second was, on the contrary, to have a large group with many associations but no strong links in particular. It was also shown that they formed groups, sometimes small, sometimes large, with a strong bond between all the dolphins. This is very characteristic of the fission-fusion tendency very present in this species (Danaher-Garcia, N., Connor., 2022). We also found that, contrary to expectations, the population is not divided into distinct groups. It would be interesting to look into this for future studies. Indeed, this anomaly could be a consequence of human activity in this region. The abundance of marine traffic could disrupt communication between individuals, preventing the formation of groups with a particular affinity The final aim of the study was to collect data to monitor the evolution of human impact on this species, but also because there is a cruel lack of data concerning this geographical area. Few studies have been carried out on the distribution and group structure of bottlenose dolphins in the Aegean Sea. To conclude this dissertation, it is fair to say that the results obtained from this dissertation correlate with the hoped-for results. So, we need to continue the research about this species to fill data gaps. To do this, we would need to vary the locations of boat surveys and verify the abundance of the population in the north of the island. Another idea is to add the variables age and sex to the boat observations. We know that group formation is strongly influenced by these two criteria. Note de contenu : Table des matières ACKNOWLEDGMENTS ................................................................................................................................................ 3 INTERNSHIP SITE........................................................................................................................................................ 4 INTRODUCTION ........................................................................................................................................................... 6 1. GENERAL CONTEXT .......................................................................................................................................... 7 1.1 SPECIES .................................................................................................................................................................................... 7 1.2 DIET ......................................................................................................................................................................................... 8 1.3 BEHAVIOR ................................................................................................................................................................................ 9 1.4 GEOGRAPHIC AREA ............................................................................................................................................................... 12 1.5 ANTHROPIC THREATS .......................................................................................................................................................... 16 1.6 IUCN ..................................................................................................................................................................................... 20 1.7 REGULATIONS ....................................................................................................................................................................... 20 1.8 PRESERVATION ACTION ....................................................................................................................................................... 21 .......................................................................................................................................................................................22 2. OBJECTIVE AND STRATEGY .........................................................................................................................23 3. MATERIALS AND METHODS .........................................................................................................................24 3.1 STUDY AREA .......................................................................................................................................................................... 24 ...................................................................................................................................................................................................... 27 3.2 BOAT-BASED SURVEYS ......................................................................................................................................................... 29 3.3 PHOTO-ID DATA COLLECTION AND ANALYSIS .................................................................................................................... 30 3.4 STATISTICS TEST .................................................................................................................................................................. 32 4. RESULTS ............................................................................................................................................................34 4.1 PHOTO-ID METHOD ............................................................................................................................................................. 34 4.2 GROUP ASSOCIATION AND DISTRIBUTION........................................................................................................................... 34 4.3 POPULATION ABUNDANCE ................................................................................................................................................... 38 4.4 MOVEMENTS BETWEEN AREAS ........................................................................................................................................... 39 4.5 ANTHROPIC THREATS .......................................................................................................................................................... 41 5. DISCUSSION ......................................................................................................................................................43 5.1 GROUP ASSOCIATION AND DISTRIBUTION........................................................................................................................... 43 5.2 ABUNDANCE ......................................................................................................................................................................... 44 5.3 MOVEMENTS BETWEEN AREAS ........................................................................................................................................... 45 5.4 HABITAT ECOLOGY ............................................................................................................................................................... 45 5.5 ANTHROPIC THREATS .......................................................................................................................................................... 45 2 5.6 CONSERVATION ACTION ....................................................................................................................................................... 46 6. CONCLUSION ....................................................................................................................................................47 BIBLIOGRAPHY..........................................................................................................................................................49 GLOSSARY ...................................................................................................................................................................56 APPENDIX ...................................................................................................................................................................57 Permalink : ./index.php?lvl=notice_display&id=113382

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