Naturalization and Spreading Routes of Branchiura sowerbyi Bedddard, 1892 (Oligochaeta) in the Volga–Baltic Waterway

During 2021–2023, the tropical oligochaeta Branchiura sowerbyi Beddard, 1892 was recorded at two stations in the Sheksna Reservoir. The finds of the individuals of different size suggest successful reproduction of the species in the Sheksna Reservoir. The success of naturalization of this species may be related to climate warming. The detection of B. sowerbyi in this reservoir occurred against the background of a five-year increase in water temperature indices. A tendency for B. sowerbyi spreading northwards was noted.