Published online by Cambridge University Press: 18 November 2009
In each month for one year 30 perch. Perca fluriutilis L., 1758. were examined for infection with Acanthocephalus lucii (Müller. 1776): 7·78°, of the population was infected with a mean intensity of 2·61 worms/infected fish. No seasonality of occurrcncc of maturation was observed owing to limited data. In older fish the incidence and intensity of infection was greater than in younger specimens. The parasite was significantly over-dispersed within the perch population, k = 00395...P(x2 = 9·07)>0·05. All specimens of A. lucii were found in the third quarter of the intestine from the pyloric caeca to the rectum. Evidence is presented in favour of mutual exclusion between A. lucii and the cestode Proteocephalus percae (Müller, 1780) and the nematode, Camallanus lacustris (Zoega, 1776).