Restitution and genetic differentiation of salmon populations in the southern Baltic genotyped with the XXXX 7K SNP array.

@entity4334 @entity12178 @entity16695
BACKGROUND: Native populations of @entity12178 in Poland, from the southern Baltic region, became extinct in the 1980s. Attempts to restitute salmon populations in Poland have been based on a Latvian salmon population from the Daugava river. Releases of hatchery reared smolts started in 1986, but to date, only one population with confirmed natural reproduction has been observed in the @entity16695 . Our aim was to investigate the genetic differentiation of salmon populations in the southern Baltic using a 7K SNP (single @entity4334 polymorphism) array in order to assess the impact of salmon restitution in Poland. METHODS: One hundred and forty salmon samples were collected from: the Polish @entity16695 including wild salmon and individuals from two hatcheries, the Swedish Morrum river and the Lithuanian Neman river. All samples were genotyped using an @entity12178 7K SNP array. A set of 3218 diagnostic SNPs was used for genetic analyses. RESULTS: Genetic structure analyses indicated that the individuals from the investigated populations were clustered into three groups i.e. one clade that included individuals from both hatcheries and the wild population from the Polish @entity16695 , which was clearly separated from the other clades. An assignment test showed that there were no stray fish from the Morrum or Neman rivers in the sample analyzed from the @entity16695 . Global FST over polymorphic loci was high (0.177). A strong genetic differentiation was observed between the Lithuanian and Swedish populations (FST = 0.28). CONCLUSIONS: Wild juvenile salmon specimens that were sampled from the @entity16695 were the progeny of fish released from hatcheries and, most likely, were not progeny of stray fish from Sweden or Lithuania. Strong genetic differences were observed between the salmon populations from the three studied locations. Our recommendation is that future stocking activities that aim at restituting salmon populations in Poland include stocking material from the Lithuanian Neman river because of its closer geographic proximity.
