Parasites of the European smelt Osmerus eperlanus (L.) of lake Ladoga

The fauna of parasites in the European smelt Osmerus eperlanus (L.), a target species of Ladoga Lake, was studied. Comparative analysis of changes in the parasitofauna of European smelt for a long-term period was carried out. It was established that the structural transformation in the parasitofauna of the Ladoga smelt appeared in the reduction of species richness due to the disappearance of typical parasitic species of oligotrophic lakes. The dominate complex of parasites of the Ladoga smelt is formed by euryhostal species with a wide range of hosts. The change in the number and structure of zooplankton and zoobenthos (food supply of Ladoga smelt) causes a decrease in the number of parasites with a complex life cycle. It was shown that changes in the species composition of smelt parasites adequately reflected the trend of general changes in the status of Lake Ladoga ecosystem under the influence of the anthropogenic factor.