Genetic diversity in a Tasmanian hatchery population of Atlantic salmon (Salmo salar L.) compared with its Canadian progenitor population

The level of genetic diversity in a cultured Atlantic salmon (Salmo salar) population from Tasmania, Australia was examined at 11 microsatellite loci and compared with that in its progenitor population from the River Philip in Nova Scotia, Canada. The reference progenitor population consisted of archived scales collected from wild River Philip salmon in 1971 and 1972, not long after salmon from this river were imported into Australia in the mid-1960s. The Tasmanian hatchery stock had a significant reduction in the mean number of alleles (31-43%) and mean allelic richness (28-39%) across all microsatellite loci compared with the wild Canadian population. Mean heterozygosity levels remained unchanged. Estimates of per-generation effective population sizes for the Tasmanian population, based on allele frequency temporal variance with the wild progenitor population, ranged from 102-207 individuals and reflected hatchery records.