Defining criteria for the reintroduction of locally extinct populations based on contemporary and ancient genetic diversity: The case of the Adriatic Beluga sturgeon (<i>Huso huso</i>)

Aim The restoration of the extinct Adriatic population Beluga sturgeon, an iconic species with economic and traditional relevance, is a priority in upcoming conservation strategies but it must not occur without deep prior knowledge on current diversity distribution. We defined informed criteria for reintroduction Italian rivers by analysing its contemporary ancient based multi-markers approach. Location Ponto–Caspian basins. Methods examined distribution pattern genetic extant beluga populations conducting analysis mitochondrial dLoop 27 nuclear microsatellites 119 individuals from 3 geographical basins (Azov, Black Caspian seas) genomic 893 SNPs isolated through 2bRAD approach subgroup 92 samples. Mitochondrial information was also used to evaluate variability few available museum Results historical sample cannot be traced back any ones laying hypothesize presence past population. Instead, data did reveal geographically clustering possibly reflecting paleogeographical changes experienced those areas. allowed us depict first time clear supported differentiation between two areas (the Black–Azov basins) revealed signal Azov sample, related management activities that area. Main conclusions outcomes study unprecedented amount can provide great benefits establishment ex situ broodstocks support future translocations. provided guidelines should taken as reference restoring activity this entire range.