Long range movements of bottlenose dolphins Tursiops truncatus and its implications for the protection of a declining Evolutionary Significant Unit in the coast of Patagonia, Argentina.

COSCARELLA, MARIANO; NIETO-VILELA, ROCÍO; DEGRATTI, MARIANA; SVENDSEN, GUILLERMO; DANS, SILVANA; GONZÁLEZ, RAÚL; CRESPO, ENRIQUE

Workshop; Joint Meeting - Scientific Comitee - Conservation Comitee / IWC; 2016

International Whaling Commission

Thefoto-identification technique has contributed significantly to the knowledge ofthe small cetacean species. Bottlenose dolphins in Patagonia were among firstpopulations in which this technique was used. The current information showsthat this population may be genetically isolated. There have been suggestionsthat dorsal fin morphology could help to differentiate geographical subgroups.Along the last 40 years it has shown evidence of declining, but the causes areunknown. A displacement to other areas has been suggested, but the home rangeof the individuals is unknown. We examined a data base comprising 184 goodquality photographs andanalyzed the captures of individually identified dolphins in San Antonio bay,Nuevo Gulf and the port of Rawson. During a span of 15 years dolphins wereidentified in the three localities; accounting individual movements of 450 km.Dorsal fins of both shapes were present in every location. San Antonio bay wasestablished as a MPA, protecting the core habitat for this population, but ourresults indicate that these dolphins have large home ranges including thesouthernmost locality where bottlenose dolphins are regularly spotted.