Ocorrência e comportamento do boto-cinza, Sotalia guianensis (Van Bénéden, 1864), a partir do ponto fixo em Morro de São Paulo, Cairu, Bahia

Abstract

Because of its coastal distribution, the Guiana Dolphin, Sotalia guianensis is directly exposed to anthropic activities that may be potentially impacting on your conservation. The State of Bahia has the largest coastline of the Brazilian coast, and this region has many sites that are potential habitats for the occurrence of the Guiana dolphin. However, there is still a great shortage of knowledge of the species throughout the state, as occurs in Morro de São Paulo, where the occurrence of the dolphin is known, but the information is limited to records of strandings and opportunistic observations. The objective of this work is study the occurrence and behavior of the Guiana dolphin, analyzing the behavioral patterns and ecological parameters associated with your local occurrence. The observations were made from a land-based in the fortress of Morro de São Paulo (Ilha de Tinharé - Bahia, Brazil), with the aid of binoculars. There were 13 days of observation, on average 8 to 9 hours per day, totaling 93 hours of sample effort. There were registered 88 individuals, forming groups of up to 5 dolphins, out of the total, 9 infants were observed. The groups were most sighted between 11 and 12 o'clock in the morning (45%), during the flood tide (53%). The most frequent behavioral states, with a total of 258 minutes of direct observation, were foraging (55%), traveling (28%) and porpoises (18%). Despite the large flow of vessels in the study area, all encounters between vessels and Guiana dolphin resulted in neutral reactions. With the accomplishment of this study, it was perceived that the place is of possible preference of habitat by the animals, so it is necessary that more observations are made in order to understand and to identify, in a medium-term temporal scale, what the ecological parameters influence the occurrence in the study area.