Genetic Assessment of Remnant Sub-Populations of Sterlet (Acipenser ruthenus Linnaeus, 1758) in the Upper Danube

While the potamodromous sterlet was common in past throughout Upper Danube Germany and Austria, it nearly vanished second half of 20th century. Until recently, only one small isolated reproductive sub-population is known from German–Austrian border. However, remnants another section downstream Vienna, near Austrian–Slovakian border, were discovered 2014. An assessment population size most important prerequisites for conservation management. This study aims to assess sizes at both sites, using genetic pedigrees comparison mark–recapture data. A total 193 samples collected these populations between 2011 2021 have been investigated. In addition, 59 captive stocks, 38 wild fish downstream, 247 profiles previous studies used comparison. Results show close relationships intermittent reproduction on site. Estimated based upon pedigree are very small, consistent with results. Small remnant limited, sporadic reproduction, as well continual losses outmigration support actions sturgeons Danube, including restoration functional migration corridors.