Repository logo

CIM1-Teses

Permanent URI for this collection

http://hdl.handle.net/10400.1/3406

Browse

Browsing CIM1-Teses by Author "Alessandrini, Anita"

Now showing 1 - 1 of 1
  • Movements of short-finned pilot whales (Globicephala macrorhynchus) in the Macaronesian biogeographical region: a photo-identification analysis
    Publication . Alessandrini, Anita; Barbosa, Ana B.
    The short-finned pilot whale, Globicephala macrorhynchus Gray (1846), is a marine mammal species from the family Delphinidae. It is a top predator species, with a circumglobal distribution from warm-temperate to tropical regions, at varying distances from shore, including the Macaronesia region (NE Atlantic). Population connectivity can profoundly influence the distribution, persistence and ecological impact of local marine mammal species. Understanding population connectivity and its environmental drivers is critical for effective wildlife conservation and management, namely in a context of increased marine pollution associated to toxic contaminants, ocean noise and disruption of natural food webs. The aim of this study was to compare Globicephala macrorhynchus individuals within the Macaronesian’ archipelagos. It includes data (digital photographs) from Madeira between 2003 and 2015, from Azores between 1999 and 2015, from the Canary Islands between 1993 and 2015, and from Cape Verde in 2006. This thesis represents the first study comparing individuals from this species within the four archipelagos of the Macaronesia. In this thesis, the method used to study the animals’ connectivity was photo-identification, which is based on the analyses of natural markings in dorsal fins. The dorsal fins were cropped from photographs and were matched to available photo-identification catalogues for G. macrorhynchus from Madeira and photos from the other archipelagos not catalogued yet. The comparison was made by eyes using image softwares, based on the number of nicks and notches in the dorsal fin of the different individuals. Results showed that 19 short-finned pilot whales were matched, being 11 individuals between Azores and Madeira, and eight individuals between Canaries and Madeira. Of these, 69% were categorized with a residency status of “transient”, 26% of “resident”, and 5% of “visitors”. This thesis supports the importance of the Macaronesia region for this species, and highlights the need for common conservation policies across different archipelagos/countries.
    2016-12-12Master thesis Open access Show more