Twenty-two species were registered in the Ubatiba system with a predominance of Characiformes and Siluriformes followed by Cyprinodontiformes, Perciformes and Synbranchiformes. Among these species four were occasional with one or two sampled individuals and restricted to one or two of the nine studied sites; the other 18 species were constant with high densities in at least one site. Most of the sampled sites presented between 11 and 18 species, all largely distributed; except for the uppermost site, located right over a waterfall 4m high, which showed at least four species and for the confluence site that presented 18 species. Canonical Correspondence Analysis indicated that environmental variables explained a great part of the density and distribution patterns of the fish species, showing that community structure of each locality was independent from the longitudinal succession, theoretically expected by the River Continuum Concept, and hardly explained by local environmental characteristics.
Coastal stream; distribution; community structure; fish
