Global Warming-Related Dynamics of Infection by Eubothrium rugosum (Plathelminthes, Cestoda) in the Burbot from the Rybinsk Reservoir

—Long-term observations (1968–2019) on the dynamics of infection by the cestode Eubothrium rugosum in the burbot (Lota lota) have been performed in the Rybinsk Reservoir on the Upper Volga. The results show that a significant and consistent decrease in the prevalence of infection has occurred in the mid-to-late 1990s and is related to global warming. Because of rise in water temperature, large zones of oxygen depletion in the bottom water layer have been formed in the reservoir, leading to mass mortality of the intermediate hosts of the cestode (ruffe and copepods). This has sharply reduced the probability of transmission of its larvae to the final host (burbot). The predicted further climate warming with abnormally hot summers may provide for further decrease in the prevalence of E. rugosum infection in the burbot.