Range Expansion of the Caspian Invader Leech Archaeobdella esmonti Grimm, 1876 (Annelida: Clitellata: Hirudinida) in the Upper Volga Basin

Abstract

A species of Caspian fauna, leech Archaeobdella esmonti, introduced earlier into most reservoirs of the Volga cascade, was recorded for the first time in the Uglich Reservoir in summer 2017. In 2009, A. esmonti was first detected in the Rybinsk Reservoir, where it was successfully established by 2015, and its occurrence frequency increased to 50%. The quantitative and size-weight characteristics of the species in the Rybinsk Reservoir are presented in this paper.