Ecologia de uma taxocenose de peixes anuais (Cyprinodontiformes - Rivulidae) num brejo de restinga, Barra de São João, Rio de Janeiro, Brasil

Abstract

Some ecological aspects of a community of three annual rivulid fishes, Cynolebias constaciae, C. whitei and Leptolebias cruzi, are studied on three temporary pools of Barra de São João (RJ). Cynolebias constanciae and L. cruzi are know only from these pools, and C. whitei occurs in other pools near Maricá and Cabo Frio (RJ). Field works were made from April, 1991 to April, 1992, in a total of 21 samples. In two collects the pools were completely dry. A total of 1670 specimens of fishes were collected, from which, only 28.9% were annual fishes. The most frequent and abundant rivulid species were L. cruzi and C. contaciae. In all three rivulid species, females were more numerous than males, mainly in the dry seasons. Stomach and gut contents were examined, the individual food itens identified and analyzed according to frequency of occurrence method. The results indicate a large number of food categories (28). All species of rivulid fishes feed on insect larvae (mainly of Chironomidae and Coleoptera), small crustaceans (Copepoda, Ostracoda and Cladocera), Hydracarina and Rotifera. The results of feeding are discussed and compared with rivulid diets at other locations.