Genetic characterization of great sturgeon brood stocks- recommendations for the conservation management and aquaculture

The great sturgeon, Huso huso, is one of the most important cultured sturgeon species in Iran, which effective management of aquaculture production of this species requires knowledge of broodstock structure, mating patterns, and genetic diversity of broodstock. The aim of the present study was the application of microsatellite DNA analysis for genetic diversity assessment in the first generation of cultured great sturgeon farmed at two centers of the live gene bank at the International Sturgeon Research Institute and Shahid Dr. Beheshti center for restoration and conservation of genetic stocks of sturgeon in Guilan province. Fin clips were sampled from 147 spawners and pre-spawners of great sturgeon at the two centers (47 samples from gene bank and 100 samples from Shahid Beheshti) in 1397-1399. Genomic DNA for amplification of microsatellite loci was extracted using ammonium acetate. Four microsatellite loci (LS68, LS57, LS19, and LS39) were amplified for examination of the genetic diversity of the two group studied sturgeons. Within 147 individuals of the great sturgeon, 198 alleles were detected (123 alleles in genebank and 75 alleles in Shahid Beheshti stocks) and all loci were disomic. The genetic diversity in gene bank and Shahid Beheshti populations were 0.44 and 0.68, respectively. Results showed that the Shahid Beheshti Center broodstocks had good allelic richness and genetic diversity and the gene bank broodstocks had good allelic richness but with reduced heterozygosity index. The genetic differentiation index (FST) between the two populations was 0.34, which indicated a low genetic differentiation between the two populations. Also, the genetic distance and similarity of Nei based on the population matrix were 1.491 and 0.225, respectively, while based on Analysis of Molecular Variance (AMOVA) genetic diversity between the two populations of great sturgeon was 92% and within the population was 8%. Genetic study of fish populations in two important fisheries centers of the country was able to provide basic information on the genetic conditions of the stocks of these valuable fish from the point of view of conservation of stocks as well as commercial aquaculture management programs.