Distributional patterns and size-weight parameters of Lithoglyphus naticoides (Gastropoda: Hydrobiidae) in the upper reach of the Kuibyshev Reservoir

The snail Lithoglyphus naticoides is one of the abundant species that colonized the upstream part of the Kuibyshev Reservoir in the early 1990s. It follows two dreissenid species by abundance and biomass characteristics in the deep benthic communities. L. naticoides inhabits nearly the full range of biotopes, probably, except the deepest areas (depths of more than 20 m). The highest abundance and size-weight parameters of this species are registered for specimens inhabiting depths of less than 10 m on shelly ground (dreissenid remains); the lowest are for the depths of more than 15 m and silts. It is revealed that L. naticoides has a one-year life cycle, reproducing mostly in July, according to the seasonal abundance dynamics, size-age structure of the population, and the average body weight.