On the occurrence of populations of the genera Cobitis and Sabanejewia (Pisces, Cobitidae) in the Czech Republic

We examined the occurrence of species within the genera Cobitis and Sabanej ewia in the water bodies of the Czech Republic. Currently Cobitis elongatoi des and its hybrid polyploid complexes are associated with the River Dyje a nd its floodplain (Danube basin), with the upper part of the River Luznice drainage area (including its fishpond area) and, further on, with the centr al area of the River Elbe. Populations of C. elongatoides and Sabanejewia b alcanica which had been reported previously in the literature were absent f rom those localities. The principal factors were polluted waters, modificat ion and regulation of water stream channels and also dam constructions. At present, C. elongatoides is considered to be critically endangered while S. aurata is no longer found in the Czech Republic.