The seasonal distribution of Echinorhynchus salmonis (Acanthocephala: Echinorhynchidae) among rainbow smelt, Osmerus mordax Mitchell, in Lake Michigan

The seasonal distribution of Echinorhynchus salmonis Müller, 1784 among rainbow smelt, Osmerus mordax Mitchell, in Lake Michigan was studied. Echinorhynchus salmonis showed no pronounced seasonal periodicity in infection prevalence and intensity or development and maturation in rainbow smelt. Worms were predominantly overdispersed with the negative binomial distribution being the best descriptive model. It is suggested that the observed monthly distributions were primarily determined by climatic and other ecological conditions affecting the heterogeneity in the temporal and spatial distribution of infection sources, i.e. Pontoporeia affinis (Lindstrom) (Amphipoda) and alewife, Alosa pseudoharengus (Wilson), and in the feeding behaviour of rainbow smelt. © 1981.