DistributionRead full entry
Range DescriptionFranciscanas inhabit shallow coastal waters (and they sporadically enter the estuary of the La Plata River) of tropical and temperate regions of the western South Atlantic Ocean (Crespo 2002). They are found only along the east coast of South America (Brazil, Uruguay, and Argentina), from the northern Golfo San Matias, central Argentina (ca. 42°10'S), to Espirito Santo, southeastern Brazil (18°25'S) (Siciliano 1994; Crespo et al. 1998). The species is not distributed continuously throughout its range. Surveys (including beach surveys, museum specimens, and interviews with local people) indicate that franciscanas are extremely rare or absent in two areas of the northern parts of their range between Macaé (southern Rio de Janeiro State) and Ubatuba (northern São Paulo State) and in Espírito Santo State (Azevedo et al. 2002; Siciliano et al. 2002; Secchi et al. 2003). The reasons for these gaps are unclear, but because the species prefers shallow, turbid waters (Brownell 1989; Pinedo et al. 1989), water transparency and depth may be among the factors responsible (Siciliano et al. 2002).
The map shows where the species may occur based on oceanography. The species has not been recorded for all the states within the hypothetical range as shown on the map. States for which confirmed records of the species exist are included in the list of native range states.