INTESTINAL HELMINTHS OF RIVER OTTERS (LUTRA-CANADENSIS) FROM THE PACIFIC-NORTHWEST

The intestinal helminth fauna of river otters, Lutra canadensis, from the Pacific Northwest was characterized by low species richness and in tensity of infection. River otters from the lower Columbia River (n = 23) were infected with 9 species of helminths (83% prevalence); those from a relatively undisturbed reference area near the headwaters of th e Trask and Wilson rivers on the Oregon coast (n = 6) were infected by 5 species of helminths (100% prevalence). Single species of Eucestoda (Schistocephalus solidus), Digenea (Euparyphium inerme), Acanthocepha la (Corynosoma strumosum), and 8 species of Nematoda (Strongyloides lu trae; larvae of Eustrongylides sp., Anisakis sp., and Contracaecum sp. ; 3 of Cystidicolidae, and Hedruris sp.) were collected. Most species are typical of piscine definitive hosts and were present as incidental parasites of river otters. Notably, specimens of Euparyphium inerme a re reported for the first time in river otters from North America; occ urrence of other helminths constitutes new host or geographic records for parasites in river otters in Oregon and Washington. Parasites with marine life cycles were acquired by river otters in freshwater habita ts at a great distance from the ocean. The helminth fauna of river ott ers in the Pacific Northwest was influenced primarily by ecological fa ctors and was indicative of eclectic food habits and the relatively ex tensive home ranges occupied by those mustelids.