The ichthyofauna of a tidal creek in Rasa da Cotinga Island, Paranaguá Bay, Paraná was studied through monthly collections in the quadrature high and low tides, with seine net of 30 m x 1.5 m and 10 mm mesh and "fyke" net of 30 m x 1.5 m with 10 mm mesh in the wings and 8 mm mesh in the bag. Together with the nekton sampling, temperature, salinity and water transparency values were also obtained as well as current speed. A total of 9068 fish belonging to 54 species and 23 families were collected. The ichthyofauna was dominated by Harengula clupeola (Cuvier, 1829), Atherinella brasiliensis (Quoy & Gaimard, 1825), Sphoeroides greeley (Gilbert, 1900) and Sphoeroides testudineus (Linnaeus, 1758), that contributed to 66.1% of the capture in number and 79.7% in weight. Statistical differences between the collection months and months groups were observed for the number of species, number and weight of fish, species richness and species diversity (weight). The observed temporal biological structure seems to be better explained by the rainfall, rainfall and salinity and combined action of the rainfall, salinity and water transparency.
Fish fauna; seasonal variation; mangrove
