Composição e estrutura da comunidade parasitária associada às espécies do gênero Pseudoplatystoma (Bleeker, 1862) (Siluriformes: Pimelodidae) da Amazônia Central, Brasil

Abstract

The objectives of this study were to find out what parasites occur in the two species of Pseudoplatystoma found in Central Amazonia and something of their ecology. Twenty one specimens of P.fasciatum and nine of P. tigrinum were collected and analized. All of the fish examined were found to host at least two parasite species. A total of 12.371 parasites belonging to 14 species were found in P. fasciatum. These included two monogenoideans, one trematode (Digenea), two nematodes, two cestodes, three copepods, three branchiurans and one isopod. In P.tigrinum, 4,227 parasites representing seven species were found. They included two monogenoideans, larval nematodes, two copepods and branchiurans. The most prevalent species found in the both hosts was the monogenoidean, Vancleavius fungulus. The parasite fauna of P. fasciatum was formed by five central, three secondary and seven satelite species. That of P. tigrinum was represented by one central, three secondary and two satelite species. Most of the species showed a basic agregate distribuition and except for Ergasilus sp. there was no positive correlation between host size and prevalence or abundance.