Seasonal distribution and ecology of three helminth species infecting carp (Cyprinus carpio) in northwest Iowa, U.S.A.

Abstract

The intestinal helminths most frequently infecting 522 Little Sioux River and 255 Lower Gar Lake carp (Cyprinus carpio) were Khawia iowensis, Pomphorhynchus bulbocolli, and Capillaria catostomi. Prevalence and mean intensity of K. iowensis were significantly higher in Little Sioux River than in Lower Gar Lake carp. Prevalence and mean intensity of P. bulbocolli and mean intensity of C. catostomi were significantly higher in Lower Gar Lake than in Little Sioux River carp. During 1979–1981, the prevalence and mean intensity of K. iowensis were highest in summer 1979 and summer 1980. Pomphorhynchus bulbocolli and C. catostomi were nonseasonal in prevalence and mean intensity. All three helminths were overdispersed within the carp population. Khawia iowensis usually occurred in the anterior third of the carp gut. Capillaria catostomi was found throughout the intestine, but most worms occurred in the posterior quarter of the gut in light infections. Pomphorhynchus bulbocolli exhibited a preference for the posterior third of the intestinal tract. Significant correlation coefficients were calculated between carp length and prevalence and (or) mean intensity of Little Sioux River K. iowensis and P. bulbocolli. Male and female carp had similar prevalences and mean intensities of each parasite species.