Fauna de metazoários parasitas do aruanã Osteoglossum bicirrhosum (Cuvier, 1829) (Osteoglossiformes: Osteoglossidae) dos rios Negro e Solimões, Amazônia Central, Brasil

Abstract

The fauna of metazoan parasites of the silver arowana Osteoglossum bicirrhosum was studied from 40 specimens captured in Solimões river and Negro river during high water periods of 2009 and 2010. A total of 20 arowanas was collected in each river, and a total of 58.016 metazoans were collected, being 54.654 parasites of fish from Solimões river and 3.362 from Negro river. The parasites found were: eight species of Monogenea, Gonocleithrum cursitans; G. aruanae; G. coenoideum; G. planacroideum; G. planacrus; Gonocleithrum sp.1; Gonocleithrum sp.2 e Gonocleithrum sp.3 in the gills; two of Digenea, Caballerotrema aruanense and a metacercariae in the intestine and stomach; two of Nematoda, Camallanus acaudatus in the intestine and pyloric caeca and Anisakidae larvae encysted in the mesentery; an individual of Acanthocephala in the intestine; one of Pentastomida, Sebekia oxycephala larvae in the mesentery; one of Copepoda Ergasilus sp. and one of Branchiura Dolops geayi in the gills. Monogenea new species, the larvae of Digenea and Anisakidae, crustaceans and Acanthocephala are new records for O. bicirrhosum. The species of Monogenea and larvae of Anisakidae had the highest prevalence and intensities and the majority of central species. Gonocleithrum cursitans and Anisakidae larvae were the dominant species. The distribution pattern of the species was aggregate. A positive relationship was observed between the abundance of endoparasites and fish length (r = 0.5106823, p = 0.00076). The Shannon index showed higher parasite diversity in O. bicirrhosum from Solimões river (H '= 1.6963), but evenness was higher in fish from the Negro river (J = 0.2918).