DISTRIBUCIÓN ESPACIAL, ESTRUCTURA SOCIAL Y AMENAZAS DE CONSERVACIÓN DE UNA PEQUEÑA COMUNIDAD DE DELFINES NARIZ DE BOTELLA, TURSIOPS TRUNCA (ODONTOCETI: DELPHINIDAE) EN ECUADOR

Spatial distribution, social structure and conservation threats of a small community of bottle[1]nose dolphins, Tursiops truncatus (Odontoceti: Delphinidae) in Ecuador. A resident community of bottle[1]nose dolphins (Tursiops truncatus) was studied irregularly between 2005 and 2018 around the tip of the Santa Elena Peninsula, Ecuador (2°11’ S & 81°0.7’ W). Opportunistic sightings and systematic surveys from the beach and at sea were carried out along 40 km of coast, accounting for 917.2 km of tracking by car from land and 707.4 km of boat tracking by sea. Average group size was 5.31 dolphins/group (SD = 1.97, range 1-10), with no sig[1]nificant changes throughout the study period. From land, however, the group size was underestimated 32 % on the average. This small bottlenose dolphin community currently has only nine individuals, including six adults, one immature and two calves, and is the smallest community within the Gulf of Guayaquil. The encounter rate ranged between 0.03 dolphins/km in the northwestern part and 0.32 dolphins/km in the South, where dolphins concentrate their activities, possibly because human activities are less intense there. Dolphins were generally distributed in the first 200 m from the shore, reaching up to 1 200 m in the Northern shallower part and where port and tourist activities concentrate.