Trophic characterization of ichthyofauna from three lagoons of the Upper Paraná river floodplain, Brazil

Abstract

Ichthyofauna from three lagoons of the upper Paraná River floodplain was evaluated according to trophic categories. Samples were obtained in the Figueira, Genipapo, and Pousada lagoons in March 1999. Stomach contents were analyzed according to methods of occurrence and volumetric frequency, combined in an alimentary index (IAi). Forty species were caught and grouped in ten trophic categories (detritivorous, ileophagous, zooplankton-feeder, algivorous, shrimp eater, piscivorous, insectivore, bentophagous, herbivore and omnivore). Zooplankton feeders (48.3%) predominated in the Pousada Lagoon, ileophagous species (74.9%) in the Genipapo Lagoon and algivorous species (75.6%) in the Figueira Lagoon. With regard to biomass, detritivorous predominated in the Pousada (45.7%) and Figueira (27.7%) lagoons, and ileophagous (90.0%) were dominant in the Genipapo Lagoon. Although the distance among lagoons is less than 1 km, the degree of influence from the Paraná river is different, since lagoons have distinct physiography and ichthyofauna composition. Several fish species presented different diets depending on the lagoon and reveal that they play distinct roles in the trophic chain of these environments