[Morphological variability and population structure of the cestode Proteocephalus longicollis (Zeder, 1800) in aquaculture].

Morphological variability of the cestode Proteocephalus longicollis (Zeder, 1800) from Coregonus peled (Gmelin, 1789) was studied in natural host population from the Pelyadka River and in aquaculture from the Kuchak Lake. Variability of morphometric characters of the parasite is recorded. Sample from the Kuchak Lake differs from the sample collected in the Pelyadka River by a greater number of testes, larger size of worms, smaller size of cirrus bursa and smaller ratio of the cirrus bursa length and the width of proglottid.