Spatiotemporal analysis shows stable genetic differentiation and barriers to dispersal in the Eurasian perch (Perca fluviatilis L.)

Background: Recently, unexpected or cryptic barriers to gene flow causing genetic discontinuities have been found in a number of animal taxa, even in apparently highly connected areas such its aquatic environments.Goal: Investigate the temporal stability of previously documented microgeographic genetic structure in a fish.Organism: Eurasian perch (Perca fluviatilis L.)Methods: We sampled four locations over a period of 2 years. We used six microsatellites to investigate population differentiation. We compared within-year to between-year differentiation.Results: The significant genetic differentiation found between locations in 2004 was still present in 2006. The strongest barriers to gene flow in the lake were consistent over both sampling periods. Furthermore, temporal differentiation existed within each site between the years. Populations of perch appear to cluster in different patches in the lake that harbour genetically differentiated groups of fish. Hence, limited migration and barriers to dispersal can persist over time, even at a very small geographical scale and in an open aquatic environment.