Rio Itaúnas is a coastal river flowing through the northern reaches of Espírito Santo, Brazil, draining a basin that encompasses a remarkable mosaic of Atlantic Forest habitats including ombrophylous forest, restinga swamps, coastal sand dunes, and mangroves. The river and its surrounding lowlands sit within the "floresta de tabuleiros" bioregion — a coastal tableland landscape that supports an exceptionally diverse freshwater fish fauna. The basin harbors a rich assemblage of species, with surveys recording a total of 83 fish species across the broader northern Espírito Santo hydrographic systems, including 47 freshwater species and 36 marine species spanning 35 families and 11 orders. This blend of freshwater and estuarine environments, combined with the river's proximity to the Atlantic coast, makes Rio Itaúnas a biologically fascinating destination for anglers interested in exploring tropical Brazilian river fishing.