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

Abstract

Estuarine dolphins, Sotalia guianensis (Van Bénéden, 1864), were identified in Sepetiba Bay (22º35'S, 44º03'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.

Photo-identification as a technique for recognition of individual fish: a test with the freshwater armored catfish Rineloricaria aequalicuspis Reis & Cardoso, 2001 (Siluriformes: Loricariidae)

“…Photo-identification has been extensively applied for studying marine mammals (e.g. Hastings et al, 2008;Nery et al, 2008), sharks and rays (Marshall & Pierce, 2012) and, more recently, has been demonstrated a feasible technique for identification of marine teleost fishes (e.g. Perrig & Goh, 2008;Giglio et al, 2014).…”

Coordinated feeding behavior of the Guiana dolphin, Sotalia guianensis (Cetacea: Delphinidae), in southeastern Brazil: a comparison between populations

“…In both Ilha Grande and Sepetiba bays, Guiana dolphin populations are present throughout the year, and most groups are composed of mothercalf pairs accompanied by juveniles (LODI 2003, NERY et al 2008. At the Ilha Grande Bay, LODI (2003) observed 1,754 individuals in 54 groups; calves were present in 89% of the groups and juveniles in 87% (LODI 2003).…”

Capture-recapture abundance estimate of Guiana dolphins in southeastern Brazil

“…Much of the complex is shallow (~6 m depth), but in some isolated areas, particularly between the islands, water depth can be 47 m (Borges 1990). This ecologically important area is surrounded by more than de delfines Guiana que son consistentemente encontrados durante todo el año; los individuos se han registrados por más de 12 años y probablemente usan la bahía para alimentarse y reproducirse (Nery et al 2008a). Datos sobre la abundancia y fidelidad de hábitat de estos delfines son esenciales para la conservación efectiva y también para fines de manejo, particularmente en áreas costeras y de estuario como es la bahía de Sepetiba, donde las poblaciones humanas se están expandiendo rápidamente, aumentando las amenazas directas e indirectas a los animales (Nery et al 2008b).…”

“…Estimación de abundancia por captura-recaptura de los delfines Guiana en el sureste de Brasil M Freitas Nery 1 *, S Marino Simão all year round; individuals have been recorded for more than 12 years and probably use the bay for feeding and reproduction (Nery et al 2008a). Data on Guiana dolphin abundance and site fidelity are essential for effective conservation and management purposes, particularly in coastal and estuarine areas like Sepetiba Bay, where human populations are rapidly expanding, increasing the direct and indirect threats to dolphins (Nery et al 2008b).…”

“…A previous abundance estimate of Guiana dolphin in Sepetiba Bay was calculated from line-transect surveys undertaken in 2002 and 2003 (Flach et al 2008a). Photo-identification has been extensively used to evaluate site fidelity, survival rates, association patterns, and disease conditions of Guiana dolphin in Sepetiba Bay since 1994 (e.g., Van Bressem et al 2007, Flach et al 2008b, Nery et al 2008a), but no abundance study using this approach has been made until now.…”