Distribution of green turtles (Chelonia mydas) in the Azores: a local ecological knowledge (LEK) approach

• Autor(a) principal: Sousa, Ana Mafalda da Silva e
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/33434
• topic: Azores; Chelonia mydas; Citizen science; Foraging grounds; Green turtles; Local ecological knowledge (LEK)

Effective conservation strategies for sea turtles require knowledge of animal movements and protection of biologically important habitats and life history stages. For juvenile sea turtles, knowing their foraging grounds and foraging ecology is imperative to the successful protection of the species and the accurate identification of their vulnerabilities. This study uses Local Ecological Knowledge (LEK) by conducting a questionnaire about the presence of green turtles (Chelonia mydas) in the Azorean Archipelago between August 2020 and April 2021. The Azores is a group of nine volcanic islands with numerous shallow-water and emergent features, as well as deep-water ridges, submarine canyons. It is influenced climatologically by the North Atlantic Subtropical Gyre and the Gulf Stream current creating the perfect condition for a biodiversity hotspot, hosting a large number of marine megafauna. Sea turtles are a common presence in the Azorean archipelago, and, even though the presence of C. mydas is of common knowledge, there are no scientific studies about the presence of this species in the Azores. The importance of LEK in data-poor scenarios is increasingly recognized in conservation. This integration of LEK data with ecological science is of critical value for conservation and management of habitats, as it contributes to a holistic view of a species’ contemporary conservation status. The green turtle is a long-lived, wide-ranging and endangered marine reptile. The ignorance of the location of its different life stages can hinder the study and management of populations. Migratory species like this one are known to pose a challenge for conservation since it is essential to understand their complex life history in order to implement efficient conservation actions. The questionnaire was divided in two sections: 1) description of the green turtle sighting and 2) interviewees’ profile. The first section was composed of 11 questions to describe the sea turtle and its surroundings. The second section had 9 questions to describe the profile of the interviewee in order to evaluate its influence on the sighting. In total, 68 interviews were performed, 27 in person and 41 online, which resulted in 87 green turtle sightings. The results confirmed the regular presence of green turtles in the Azorean archipelago. The description of the straight carapace length (between 10 cm and 79 cm) confirmed that all green turtles in this area are juveniles. Most sightings occurred during the summer and autumn, close to the rocky sea floor at around 8 meters deep. Since the majority of the interviewees were from Faial and Pico islands, that is where most sightings occurred. This study is the initial study of green turtles in the Azores. It opens the doors to conduct more systematic and hypothesis-driven studies to feed future management strategies in which local people are active participants, especially considering they are at the frontline of conservation in these isolated areas of the archipelago.