<b>Ecology of parasites of <i>Metynnis lippincottianus</i> (Characiformes: Serrasalmidae) from the eastern Amazon region, Macapá, State of Amapá, Brazil

The present study provides the first investigation on the ecological aspects of the parasites M. lippincottianusfrom the Amazonian basin, as well as the parasite-host relationship. 76 out of the examined fish (98.7%) were parasitized by at least one species of parasites. A total of 8,774 parasites were collected, being Ichthyophthirius multifiliis, Anacanthorus jegui, Dadayius pacupeva, Digenea gen. sp. (metacercariae), Procamallanus (Spirocamallanus) inopinatus, Procamallanus (Spirocamallanus) sp., Spinoxyuris oxydoras, Contracaecum sp. larvae, Dolops longicauda and Hirudinea gen. sp. Ichthyophthirius multifiliis was the dominant species, followed by A. jegui. Among the endoparasites, S. oxydoras and D. pacupeva were predominant. The mean diversity of parasites was HB = 0.96 ± 0.32 and there was aggregate distribution pattern. A positive correlation of body weight with the abundance of I. multifiliis and S. Oxydoras was observed, whereas a negative correlation of body weight with abundance of the Contracaecum sp. larvae was found. The relative condition factor (Kn) was not negatively affected by parasites, and a positive correlation between Kn and abundance of I. multifiliis, S. oxydoras and D. pacupeva was found. This study is the first one to record I. multifiliis, D. longicauda and A. jegui parasitizing M. lippincottianus, as well as the first record of D. pacupeva and S. oxydoras in the Amazonas river system