Genetic characteristics of Atlantic salmon (Salmo salar) stocking material released into Polish rivers

In Poland, stocking rivers with Atlantic salmon (Salmo salar L.) began in the nineteenth century, and become intensive in the 1990s. Currently, it is performed by the Polish Angling Association, and institutions involved in the program “Stocking Polish Marine Areas.” The aim of this study was to evaluate the genetic variation of the salmon stocked in recent years in Poland. For this purpose, salmon stocks from three broodstocks and two river populations (Słupia and Parsęta) were investigated. Eleven microsatellite loci were amplified. The total number of alleles detected across all loci ranged from 46 to 81 in the stocks. The average observed heterozygosity across all investigated loci was 0.59; and the expected heterozygosity was 0.58. The populations remained in Hardy–Weinberg equilibrium. The average Garza-Williamson M index value for all populations was low suggesting a reduction in genetic variation because of the founder effect. Genetic distance among populations was high between the Lithuanian stock (Rutki and Parsęta) and the group of Latvian origin (Aquamar–Żelkówko–Słupia). Several admixture traces were recorded in all stocks with the smallest evidence of this in the Rutki stock. Inbreeding values per generation were typical of those observed in breeding stocks (0–3%). The effective population size values were low or very low for all the stocks (Ne 15-37).