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Gill Ectoparasites of Juvenile Rainbow Trout and Brown Trout in the Upper Colorado River
Author(s) -
Schisler George J.,
Walker Peter G.,
Chittum Linda A.,
Bergersen Eric P.
Publication year - 1999
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(1999)011<0170:geojrt>2.0.co;2
Subject(s) - rainbow trout , brown trout , biology , salmo , juvenile , infestation , trichodina , fishery , trout , ecology , zoology , fish <actinopterygii> , gill , botany
During 1996 and 1997, 112 rainbow trout Oncorhynchus mykiss and 204 brown trout Salmo trutta , all young of the year, were sampled from a 40‐km study area of the upper Colorado River and were examined for gill parasites. Ambiphrya, Chilodonella, Ichthyobodo, Apiosoma, Trichodina, Trichodinella, Tripartiella, Epistylis , and an unidentified cochliopodid amoeba were the representative protozoan genera observed on fish examined. Significant month–year–species interactions ( P = 0.0295) were revealed, reflecting the changes in infestation prevalence among months, years, and species of salmonid. Greater ectoparasite richness was observed in downstream sections of the study area, most notably near Hot Sulphur Springs, Colorado. Peaks of infestation intensity and ectoparasite richness occurred in August and September of both years, presumably because of high mean water temperatures and low flows during that time.