Abstract:
Three parasites of yellow perch, Perca flavescens, in four Canadian Shield lakes were studied for their effects on perch growth and mortality. Glugea sp. xenomas in cells of the intestinal wall and in visceral fat and Apophallus brevis metacercariae infecting the musculature reduced the growth of perch, causing mortality in younger and smaller fish. High numbers of Raphidascaris acus encysted in the liver of yellow perch correlated significantly with a reduction in visceral-fat mass in age 1+ females and age 0+ and 1+ males. A significant correlation in these subsamples indicates that host sex, size, trophic status, and relative mass of the liver are linked to R. acus density. Our data suggest that interactions among parasitic infections and age, size, and sex of the fish host can affect growth and survival of the host, especially during periods of low energy inputs and reproductive stress.
