Spatial and temporal distribution and photo identification of short-finned pilot whales (Globicephala macrorhynchus) off São Miguel Island, Azores, Portugal

• Autor(a) principal: Negulescu, Ramona
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/15324
• topic: Golfinho Risso; Atividades antrópicas; Subaquático; Baleia-piloto; Plataforma; Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais

The Azores archipelago is home to 28 different species of cetaceans, among which the long- and short-finned pilot whales (Globicephala melas and G. macrorhynchus). Of the two species, the latter is more frequently spotted in the area and, as a consequence, it is the subject of the current study. The species is vulnerable to threats resulted from anthropogenic activity, such as boat strikes, underwater noise or being caught as bycatch, which makes the assessment of their status essential for conservation. The aims of this master thesis were to evaluate the spatial and temporal distribution of pilot whales along the south coast of São Miguel island, as well as to compile a photo identification catalogue in order to distinguish the individuals that transit the island, find out whether or not they return to the area and identify specific associations. The study used data collected from a platform of opportunity offered by the whale watching boats belonging to Futurismo, as well as data collected from land by the look-outs working for the company that were responsible for finding the animals and signaling their presence. In addition, photographs taken from the boats were processed and analysed for the identification of individuals. The results show that short-finned pilot whales are spotted in the south of São Miguel more during the summer season, with higher encounter rates in July, followed by the month of June. They frequent waters between 700 and 1200 m deep, with slopes of 2° to 6° and were encountered between 4 and 20 km from the coast. A total number of 343 pilot whales were identified, out of which 42 were sighted more than once. However, as the re-sighting rate was too low to allow for the analysis of their social structure, further research is needed to assess it.