Diversity of metazoan parasites in Colossoma macropomum (Serrasalmidae) from the lower Jari River, a tributary of the Amazonas River in Brazil

ABSTRACT This study investigated the diversity of metazoan parasites in Colossoma macropomum from the Jari River, in the eastern Amazon, northern Brazil. We collected a total of 4966 parasites from 34 fishes, including monogeneans (Anacanthorus spathulatus, Mymarothecium boegeri, Notozothecium janauachensis and Linguadactyloides brinkmanni), nematodes (Spectatus spectatus larvae, Contracaecum sp. larvae andProcamallanus (Spirocamallanus) inopinatus), digeneans (Cladorchiidae metacercariae), acanthocephalans (Neoechinorhynchus buttnerae), crustaceans (Ergasilus turucuyus, Argulus multicolor, Perulernaea gamitanae and Braga patagonica), mites and leeches. The dominance was of monogenean species, found in the gills of the hosts. The parasites exhibited high aggregate dispersion, except Contracaecum sp. and P. (S.) inopinatus, that showed uniform and random dispersion, respectively. The species richness of parasites varied from 1 to 9, the Brillouin diversity index from 0 to 1.52, evenness from 0 to 0.63 and the Berger-Parker dominance index from 0.39 to 1.00. Abundance of parasites was not influenced by host length, but there was significant correlation with host body weight in some cases. The parasite community was characterized by low species richness and moderate diversity, with a predominance of ectoparasites with high prevalence and abundance, as well as the presence of endoparasites in the larval stage.