Fishfauna trophic structure across longitudinal gradient of Salto Caxias Reservoir (Iguaçu River – state of Paraná – Brazil) in the third year after dam - DOI: 10.4025/actascibiolsci.v27i1.1362

Abstract

This study aims at evaluating the fishfauna trophic structure across the longitudinal gradient of Salto Caxias reservoir, in the third year after its dam (post 3). The data obtained were compared with the previous ones (pre and post 1) to verify if the species that altered their diets in the initial phase of the dam, returned to the same food resources offered by natural environment. S(tomachal) contents of 1527 fishes were analyzed, using the volumetric method. In general, fishes presented a great diversity of food items in their diets, usually with a predominant resource kind. Thus, the fishfauna was synthetized in eight trophic guilds. The detrivore and piscivore species did not alter their feeding habit across spatial gradient considerably). (A montanteUpstream, all the trophic guilds were equally distributed compared to the other sites. Comparing pre and post 1 periods with the post 3 results showed that few species returned to their original trophic habit