[Parasitic helminths infection in Coho salmón, Oncorhynchus kisutch, during their return to Simpson river, Chile].

Between may and july 1994, 17 adult returning salmons, Oncorhynchus kisutch, were collected in the River Simpson, Chile. All fishes showed infection by plerocercoids of Diphyllobothrium sp. in different locations: stomach, spleen, liver, mesenteries and gonads. Infection with larval cestodes of an unidentified species of Phillobothriidae was determined in the intestine of seven (41.2%) salmons and its prevalences of infection showed significant differences between female and male salmons. The 94.4% of total plerocercoids of Diphyllobothrium were isolated from the stomach wall. Prevalence and mean intensity of infection by Diphyllobothrium sp. did not show significant differences between fishes of different sex.