Occupation pattern of a harbor inlet by the estuarine dolphin, Sotalia guianensis (P. J. Van Bénéden, 1864) (Cetacea, Delphinidae)

Abstract

The occupation pattern of Sotalia guianensis in São Francisco do Sul harbor inlet, in Babitonga bay, southern Brazil, was studied between September 1996 and June 1998. A total of 200 h of naturalistic observations and 141.2 h of estuarine dolphin systematic observations were made using binoculars 7 x 50. At each three minutes interval, data about number of individuals and behavior were registered. The population used the harbor inlet intensively, mainly for fishing activities. Ebb tide was responsible for a higher occupation index. Considering the months analyzed, the higher occupation index occurred in May, and in January the lower occurrence was observed. The mean group size was four individuals.