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

Author
item Hoberg, Eric
item HENNY, C - DEPT. OF INTERIOR
item HEDSTROM, O - OREGON STATE UNIVERSITY
item GROVE, R - OREGON STATE UNIV

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/7/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: The biodiversity of parasitic helminths in North American vertebrates is poorly known. Knowledge of the distribution of helminthic parasites provides insights into ecological interactions in aquatic and terrestrial habitats. As part of a cooperative interagency investigation in biodiversity with the National Biological Service, the helminth fauna of river otters in the Pacific Northwest was evaluated for the first time. A comparison was conducted between otters in a polluted habitat on the Lower Columbia River and a relatively pristine environment of the Coast Range of Oregon. Levels of parasitism by helminths were not shown to be substantially different. In both areas the parasite fauna was typical of hosts which foraged extensively on fishes and amphibians. The importance of anadromous salmonids in the diet was indicated by the occurrence of several parasites from marine habitats. As parasites are associated with predictable life cycles, this forms the basis for understanding changing patterns of habitat use and foot habits by otters in areas which are being influenced by anthropogenic factors.

Technical Abstract: The intestinal helminth fauna of river otters, Lutra canadensis, from the Pacific Northwest was characterized by low species richness and intensity of infection. River otters from the Lower Columbia River (n=23) were infected with 9 species of helminths (83% prevalence); those from a reference area near the headwaters of the 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) Acanthocephala (Corynosoma strumosum) and 8 of Nematoda (Strongyloides lutrae, larvae of Eustrongylides sp., Anisakis sp., 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 are reported for the first time in river otters from North America; occurrence of other helminths constitute new host or geographic records for parasites in river otters in Oregon and Washington. The helminth fauna of river otters in the Pacific Northwest was influenced primarily by ecological factors and was indicative of eclectic food-habits and the relatively extensive home-ranges occupied by these mustelids.