A newly discovered population of the Balkan spiny loach Sabanejewia balcanica (Karaman, 1922) in the River Jihlava, Czech Republic

Abstract. In the Czech Republic, the Balkan spiny loach Sabanejewia balcanica was historically only known from the River Bečva, a left tributary of the River Morava, itself a main tributary of the River Danube. Following its assumed extinction in the Czech Republic, a small population was found in a 1 km stretch of the River Vlára at the Slovak border, with individuals presumably having migrated from Slovakia. In 2016, we recorded six individuals in the downstream stretch of the River Jihlava. Based on present knowledge, this appears to be a population situated wholly outside of its previously known area of distribution, and the only population presently found in the 26000 km2 River Morava drainage basin. The distance of this population from the species' present distribution area and historic findings in the River Bečva clearly indicate a much wider historical distribution of this species in the past.