Restocking has been considered the primary practical tool in gene pool conservation of sturgeons in the Caspian Sea since five decades ago. In spite of the long term restocking activities in southern Caspian Sea, no genetic monitoring using novel genomic-based approaches has been done to investigate the genomic population structure of these valuable species in the south of the Caspian Sea. Acipenser persicus is the main species under restocking program in the south of the Caspian Sea, hence, during the present study we used low-pass whole- genome sequencing method to investigate the genetic consequences of restocking on this species across the southern Caspian basin. For this, we sampled fin tissue of 20 wild A. percisus being caught for restocking in two main restocking centers across the south of the Caspian Sea (located in Guilan and Mazandaran provinces). After genomic DNA extraction, whole-genome libraries were sequenced on a lane of Illumina Novaseq 6000 at the facilities of Novogene as 150 bp paired-end reads. The observed heterozygosity based on 57 million SNPs obtained 0.34 and 0.36 and the inbreeding coefficient (Fis) was 0.09 and 0.06 at Guilan and Mazandaran, respectively. The Fst as an index of populations’ segregation was 0.024, indicating a low rate of populations’ separation. Supportively, the admixture analysis showed a considerable admixture structure implying a shallow population structure between the two investigated geography regions. However, Co-ancestry based analysis illustrated that still two genetic populations of A. persicus can be taken into consideration for genomic conservation purposes in the south of the Caspian Sea. The output of this study reviled that while restocking has aided the genetic conservation of A. persicus, actions other than that of seldom restocking such as river rehabilitation are required to prolong the resilience of A. persicus in the south of the Caspian Sea.

Genomic conservation, Molecular ecology, Persian sturgeon, Population assignment, Restocking