Alimentação, distribuição espacial e sazonal das espécies de Arius (Siluriformes : Ariidae) do Estuário amazônico

Abstract

The Family Ariidae (Order Siluriformes) contains marine and estuarine catfishes distributed along the coasts of ali the continents, inhabiting tropical and subtropical shores where they live in shallow waters with sandy or muddy bottoms. In the Amazon River estuary in Pará State, Brazil, there are seven species belonging to the genus Anus (A. couma, A. parkeri, A. rugispinis, A. quadriscutis, A. grandicassis, A. phrygiatus e A. proops). The aim of this study is to identify feeding preference, feeding overlap, spatial distribution and seasonal distribution of the species of genus Anus (Siluriformes, Ariidae) of the Annazon stuary. Collections were made from August to October 1996, and February to April and August to October 1997. Specimens were captured with bottom nets without escape doors belonging to the piramutaba fishing fleet of the Amazon estuary. There are two species groups in the genus Anus: those that feed on crustaceans (A. rugispinis, A. quadriscutis, A. grandicassis, A. phtygiatus e A. proops), and those that feed on fish (A. couma, A. parken). In relation to feeding overlap, ali the species demonstrated a certain degree of feeding overlap, as well as spatial overlap. A. couma and A. phrygiatus. are the most abundant in the 5-10 m depth range and A. rugispinis, A. quadriscutis, A grandicassis and A. parkeri e A. proops in the 10-20 m range. A. phrygiatus is the only species that has a greater abundance during the rainy season, and the other species are present both in the dry as well as the rainy season.