Wpływ działalności gospodarczej człowieka na faunę pasożytów ryb

Results of investigations on the influence of introduction of various fish species to lake biocenosis on the parasite fauna of fishes are presented. Phytophagous fishes: Ctenopharyngodon idella, Hypophthalmichthys molitrix and Aristichthys nobilis, introduced to lakes Warniak and Dgał Wielki (Mazurian Lakeland) caused great changes in biocenoses of these lakes (destruction of aquatic plants followed by impoverishment of invertebrate fauna). An indirect bearing of these changes on the parasite fauna of native fishes was manifested either in a reduction of the quantity of some common parasites (Tylodelphys, Ergasilus) or in their increase (Ichthyocotylurus spp.). Some less common or numerous species of parasites showed a tendency to disappearance (e.g. acanthocephalans). The introduced fishes enriched the parasite fauna with 4 species. They were also susceptible to native parasite infections (Ergasilus, Diplostomum, Apharyngostrigea).