Report of the Working Group on Major Threats and Conservation

Abstract

The species of the genus Sotalia inhabit river and lake systems of Amazonia, the lower Orinoco River, and coastal marine waters from Nicaragua to southern Brazil (Borobia et al., 1991; da Silva and Best, 1994; 1996; Carr and Bonde 2000; Flores and da Silva, 2009). Freshwater and marine animals can be differentiated based on skeletal morphology (Monteiro Filho et al., 2002). Recently they were demonstrated to be separate species, with S. fluviatilis being the riverine species in the Amazon and S. guianensis being found in marine and estuarine environments (Cunha et al., 2005; Caballero et al., 2007). The identity of the animals found in the Orinoco system remains unclear (see Solé-Cava et al. 2010, this volume). Both species are believed to be locally abundant, although numbers reported for some areas (such as Guanabara Bay, Rio de Janeiro) seem to have declined (Santos et al., 2010, this volume; Azevedo et al., 2008). Common names for the riverine species S. fluviatilis include ‘tucuxi’ in Brazil or ‘bufeo negro’ in other countries, while the marine species S. guianensis is called ‘boto-cinza’, or simply ‘boto’ or ‘golfinho’ in Brazil. The proposed English common name for S. guianensis is ‘Guiana dolphin’ (Flores et al., 2010 this volume).