Vanishing of an isolated population of thick-clawed crayfish Astacus pachypus (Crustacea: Decapoda: Astacidae) in the Sevastopol Bay(Crimean Peninsula, Black Sea)

摘要

In the XIX and XX centuries thick-clawed crayfish Astacus pachypus was reported for the Sevastopol area in Crimea. Nowadays significant changes of hydrolological conditions and substrates took place in the only possible locality where a population ofthis species could exist — inner part of the Sevastopol Bay and the mouth of River Chernaya. Biotopes characteristic for this place in the XIX century were lost. Since the conditions optimal for thick-clawed crayfish in the River Chernaya estuary are currently absent, this species most likely has vanished from the Sevastopol area.