Five Barbus populations were analyzed by enzyme electrophoresis to verify hybridization between two species in Spain, B. meridionalis and B. haasi. Two populations supposed to be hybrid have been named B. meridionalis-2 and B. haasi-2 because of their morphological resemblance to the corresponding parent species. 88.9% of B. haasi-2 genes are of the "meridionalis" type, a value obtained using six loci distinguishing the two species. None of the individuals in this population was identified as an F1 hybrid. On the other hand, B. meridionalis-2 showed no sign of introgression and is thus a population of the pure species B. meridionalis. The absence of known current contact between the hybrid population and both parent populations and the present genetic results suggest that the hybridization is currently interrupted in the studied locality.
