The ichthyofauna in two tidal flats of the euhaline section of Paranaguá Bay, PR

Abstract

The structure of the fish assemblies and the function of tidal flats as breeding areas were described. The samples were collected monthly on the quadrature low tide with a seine net (30 x 1.5 m and one cm mesh between adjacent knots), in two tidal flats of the euhaline section of Paranaguá Bay: one in front of a marsh, subject to more intensive currents and with the prevalence of fine sand, and other in front of a mangrove, in an area with less intensive currents and a substratum formed mainly by very fine sand. Simultaneously to the drags, water temperature, salinity and transparency data were obtained. In the two tidal flats, small fishes and few species dominated the captures; however, the order of importance of the species was relatively different. In the area subject to the more intensive currents, the species Atherinella brasiliensis predominated, followed by Harengula clupeola, Sphoeroides testudineus, Stellifer rastrifer and Sphoeroides greeleyi, while in the protect area the numeric dominance was of H. clupeola, A. brasiliensis, S. greeleyi and S. testudineus. Fifteen species were exclusive to the collections made in the tidal flat of the marsh, and five species were present only in the other tidal flat. Community structure indexes do not indicate seasonal changes in the fish assemblies in the two tidal flats. Anosym and Simper routine of Primer demonstrate that the ichthyofaunal composition of the two tidal flats do not differ markedly.