Abstract
A total of 311 perch were examined for gut parasites during the period from April 1972 to December 1973. Four different metazoan parasites were found;Proteocephalus percae (Müller, 1780),Bunodera luciopercae (Müller, 1776),Acanthocephalus lucii Müller, 1776 andCamallanus lacustris Zoega, 1776.B. luciopercae andP. percae exhibited similar seasonal cycles in appearance and abundance. They were both absent from the fish population during June/July.A. lucii andC. lacustris on the other hand had a peak in infection intensity and incidence during the summer and autumn months. From September/October one year to May/June the following yearB. luciopercae was the dominating parasite species showing the highest incidence (≈95%) and intensity (a mean of about 25 parasites per infected fish). When 2×2 contingency tests were applied on the material from this period a significant negative correlation between the presence ofP. percae andA. lucii could be pointed out while there was no correlation between the presence of any of the other 3 parasite species.