GROWTH, MORTALITY, AND HEMATOLOGY OF CUTTHROAT TROUT EXPERIMENTALLY INFECTED WITH THE BLOOD FLUKE Sanguinicola klamathensis

¹ Department of Zoology, Brigham Young University, Provo, Utah 84601, U.S.A.

Studies were made of the growth, mortality, and blood changes of cutthroat trout (Salmo clarki) experimentally infected with the blood fluke, Sanguinicola klamathensis Wales 1958. Five hundred non-infected cutthroat trout fingerlings and 500 exposed to a population of 6000 Fluminicola fusca snails with a 6% prevalence of infection with the blood fluke S. klamathensis were maintained for several months. Following 3 months exposure to the blood fluke infection, the experimental group had 80% mortality. Packed cell volumes and oxyhemoglobin levels were reduced significantly in the experimental fish as compared to the controls. Control fish continued to grow logarithmically in total weight, while the experimental fish declined in total weight due to parasitism and mortality. There were significant differences between the two groups for the average weight per fish and the average length per fish during the period of mortality.