Seasonal variation in genetic population structure of sábalo (Prochilodus lineatus) in the Lower Uruguay River

Abstract

Prochilodus lineatus is a highly migratory fish species that sustains the most important commercial fishery of Parana-Paraguay basin. Migratory patterns are poorly known and only few population genetic studies are avaliable for this species in the Upper Parana. To assess genetic population structure, we genotyped a sample of 93 individuals from the Lower Uruguay River close to Gualeguaychu city (Entre Rıos, Argentina) at three different times, July 2008 (Winter), September 2008 (Spring) and May 2009 (Fall). All individuals were genotyped for 12microsatellite loci previously found to be informative to assess populations of P. lineatus. Our results show seasonal variation of the genetic sub-structuring at this locality that may be related to the presence of different migratory stocks throughout the year. The Fall sample includes an additional genetic cluster of individuals not detected in Winter and Spring, suggesting that this species should be considered a mixed stock fishery.