On the Helminth Fauna of the great Cormorant, Phalacrocorax Carbo, in Lake Ladoga, Northwestern Russia

New data on the species composition of parasites of the Great Cormorant, Phalacrocorax carbo, from the coasts of Lake Ladoga are presented. The parasitic fauna of the Great Cormorant consists of 9 species. Four species are found in the Northwest of Russia for the first time: the trematode, Metorchis xanthosomus, and the nematodes, Cyathostoma microspiculum, Syncuaria squamata, and Eustrongylides mergorum. P. phalacrocoracis, Syncuaria squamata and Cyathostoma microspiculum are parasites specific of cormorants. Other identified parasites (Contracaecum rudolphii, Petasiger radiatus, P. phalacrocoracis, Paradilepis scolecina, Ligula intestinalis) are typical and widespread helminthes of fish-eating birds that are ubiquitous in the Palaearctic. Some species (M. xanthosomus, E. mergorum, C. rudolphii and L. intestinalis) are of epizootic importance.