Parasites of Fishes of Aishihik and Stevens Lakes, Yukon Territory, and Potential Consequences of Their Interlake Transfer Through a Proposed Water Diversion for Hydroelectrical Purposes

Abstract

Forty-six species of parasites (14 Protozoa, 7 Monogenea, 7 Digenea, 8 Cestoda, 2 Acanthocephala, 4 Nematoda, 3 Copepoda, and 1 Hirudinoidea) were recovered from 383 specimens of 8 species of fishes collected from Aishihik and Stevens lakes, Yukon Territory, during the summer of 1973. Four species, Chloromyxum dubium Auerbach, 1908, C. esocinum Dogiel, 1934, Sphaerospora cristata Shulman, 1962 (all Protozoa), and Crepidostomum metoecus Braun, 1900 (Digenea) are reported for the first time from North America.Aspects of the systematics and distribution of several species are discussed and the following new synonymies recognized: Tetraonchus rauschi Mizelle and Webb, 1953 with T. borealis (Olsson, 1893) (Monogenea);Cystidicola stigmatura (Leidy, 1886) with C. farionis Fischer, 1798; and Raphidascaris canadensis Smedley, 1933 with R. acus (Bloch, 1779) (both Nematoda).Substantial differences in the parasite fauna of Aishihik and Stevens lakes are noted; the possible consequences of the introduction of species of potential economic and pathogenic importance e.g. Henneguya zschokkei (Gurley, 1893), Hexamita salmonis (Moore, 1923) (both Protozoa), Discocotyle sagittata (Leuckart, 1842) (Monogenea), Neoechinorhynchus rutili (O. F. Müller, 1780) (Acanthocephala), and Triaenophorus nodulosus (Pallas, 1781) (Cestoda) into new areas as a result of the proposed diversion of Stevens Lake (Yukon River system) into Aishihik Lake (Alsek River system) are discussed.