Population biology of the nematode Camallanus lacustris in perch, Perca fluviatilis L., from an oligotrophic lake in Norway

Abstract

Samples of perch, Perca fluviatilis, were examined for the contents of their gastrointestinal tract and for the intestinal nematode Camallanus lacustris (Zoega). The seasonal dynamics, dispersal pattern and site preference of the nematode were studied. Both larvae and adult worms were present in the perch throughout the year. The abundance of C. lacustris was non‐seasonal, but seasonal cycles were found in the numbers of larvae and of gravid females. C. lacustris showed a tendency to an increase in mean intensity with the size of perch. The frequency distribution of the nematode followed the negative binomial at different times of the year and in different length groups of perch. C. lacustris showed a seasonal site preference in the perch gut.