Rozmieszczenie Proteocephalus exiguus [Cestoda] w przewodzie pokarmowym sielawy Coregonus albula z jeziora Ukiel

The distribution of Proteocephalus exiguus in the gut of vendance was examined with regard to the age of parasites and infrapopulation density in individual hosts. The tapeworms can occupy the whole length of the intestine, but they are most abundant in its middle and posterior parts. The distribution of four age classes changed in relation to the infrapopulation density. In higher densities young specimens prevailed in the anterior part of the intestine, while the gravid ones were in its posterior part. The possible reasons of such an „age segregation" are discussed.