Seasonal variation in the ichthyofauna of Maciel, Paranaguá Bay, Paraná

Abstract

The objective of this study was to identify any seasonal differences in the fish assemblage from the Paranaguá Bay Estuary, Paraná, using a “capéchade” stow net. The samples were obtained between July 2006 to June 2007. A total of 39711 individuals, representing 69 species belonging to 32 families were collected, with Atherinella brasiliensis, Harengula clupeola, Sardinella brasiliensis, Diapterus rhombeus, Eucinostomus argenteus, Pomadasys corvinaeformis, Bairdiella ronchus, Sphoeroides greeleyi and Sphoeroides testudineus being the most prevalent species. Anchoa lyolepis and Harengula clupeola represented more than 61% of the total number, while Pomadasys corvinaeformis contributed to 28% of the total weight, followed by Harengula clupeola (16%). The average standard (± SE) length and weight were 87.6 mm (± 32.2 mm) and 22.5 g (± 27.8 g), respectively; demonstrating a dominance of small individuals, most of which were juveniles. There were no significant differences between months in terms of the Margalef diversity (D), Shannon-Wiener diversity (H’) and Pielou’s evenness index (J’). There was seasonal variation in the numbers of individuals and species and their capture weight and standard length. The average numbers of individuals and species were greater during warmer months, while biomass were greater at the end of autumn and winter, and standard lengths higher in May and June.