Through a monthly beach seine survey programme carried out in the coastal beach of Mar Casado (Guarujá-SP) and in the estuarine beach of Mar Pequeno (São Vicente-SP), from May, 1984 to May, 1985, it was yielded a total of 5723 individuals of 42 species of marine and estuarine fish. A list of species, seasonal occurrence and relative abundances is presented. For each area, we found only five dominant species as: in Mar Casado, Trachinotus carolinus and T. falctus (Carangidae), juveniles of Mugilidae, Harengula clupeola (Clupeidae) and Eucinostmus melanopterus (Gerreidae); in Mar Pequeno, juveniles of Mugilidae, Xenomelaniris brasilienses (Atherinidae), Opisthonema oglinum and Harengula clupeola (Clupeidae). In Mar Pequeno we found the greatest richness of species, the highest values of individuals's number, and CPUE, apparently related with water's temperature that are lower in winter and higher in summer-fall. The Shannon-Weaver Index was calculated to determine the diversity of ichthyofauna; it varies seasonally and seems not to be related with any hydrological parameters.
Brackiswater fish; Marine fish; Abundance; Seasonality; Species diversity; Check lists; Guarujá; São Vicente