Population biology of Allocreadium lobatum Wallin, 1909 (Digenea : Allocreadiidae) in the Creek chub, Semotilus atromaculatus, Mitchill (Osteichthyes: Cyprinadae), in a Nebraska Creek, USA

Allocreadium lobatum Wallin, 1909 has been reported in cyprinid species of freshwater fish in Canada and in the United States. The population biology of A. lobatum in the host Semotilus atromaculatus Mitchill was studied from May through December 1991, in a USA creek. Overall prevalence (64%) and me an intensity (4.4 +/- 0.4) were greater than previously reported while abun dance, reported for the first time, was 2.8 +/- 0.3. Several trends in A. l obatum population biology as a function of S. atromaculatus length were ide ntified. Mean intensity and abundance of A. lobatum increased with host siz e and significant differences in prevalence and A. lobatum lengths were fou nd to correlate with host lengths.