An investigation was begun July 1, 1962 to determine the potential of snails infected with cercariae of Posthodiplostomum minimum to produce infection in bluegills, Lepomis macrochirus. Infected snails, in aluminum wire baskets, were stocked into plastic-lined pools at rates of 1 or 5 per pool. Bluegills of 2 sizes, 1-inch or 3-inch, were stocked into the pools. All bluegills were exposed to cercariae for 24 days at which time the experiment was terminated. One month later counts were made of the parasites found in each fish. One-inch bluegills contained an average of 20 parasites per fish when exposed to cercariae from 1 infected snail and 37 parasites per fish when exposed to cercariae from 5 infected snails. Three-inch bluegills contained an average of 110 parasites per fish when exposed to cercariae from 1 infected snail and 200 parasites per fish when exposed to cercariae from 5 infected snails. Comparison of treatment means revealed that the intensity of infection was related more to the size of the fish than to the number of infected snails to which the bluegills were exposed.
