Parasitism of native fishes from Laja river basin (Región del Bío-Bío, Chile) and approaches about life cycles

Abstract

The parasites from three species of native freshwater fishes, Trichomycterusareolatus, Diplomystes nahuelbutaensis and Percilia irwini, common from Central Chile were studied. These parasites are interesting because they could infect farmed salmon. Fishes were caught from an Andean watershed (37º20S; 72º56W) and examined in laboratory for parasites. A camera placed on a stereomicroscope and microscope were used for the photographs and observations. The specimens were later fixed in formalin at 5% or ethanol at 70%. The prevalence and intensity of seven parasites taxa were recorded: Mixobolus sp., Henneguyasp., Ancrynocephalidae (Monogenea), Zoogonidae (Digenea), Steganodermata sp (Zoogonidae), Nematoda and Pomphorhynchus sp. (Acanthocephala). P. irwini harbours the most diverse and rich parasite assemblage with 4 species, followed by T. areolatus with 3 taxa. D. nahuelbutaensis have only one parasite species but with high prevalence levels (89%). The life cycle of these parasites, the possible new host-parasite association and its consequences are discussed.