Site fidelity of Sotalia guianensis (Cetacea: Delphinidae) in Sepetiba Bay, Rio de Janeiro, Brazil

Estuarine dolphins, Sotalia guianensis (Van Beneden, 1864), were identified in Sepetiba Bay (22 degrees 35'S, 44 degrees 03'W), state of Rio de Janeiro, Brazil, between February 1994 and July 2006 using the photo-identification method. A total of 72 Surveys resulted in the identification and cataloguing of 217 individual dolphins. Seventy-nine (36%) were resighted at least once during the study period. The average interval between resightings was 40,6 +/- 31,1 months. Large numbers of mother-and-calf pairs were recorded during the 12 years and new individuals were frequently encountered in the photographic records. These results suggest that part of the dolphin population is more consistently found in Sepetiba Bay, probably for feeding and reproduction, while other individuals use the Bay only sporadically.