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Gollmann, G., Y. Bouvet, R. M. Brito, M. M. Coelho, M. J. Collares-Pereira, A. Imsiridou, Y. Karakousis, E. Pattee and C. Triantaphyllidis (1998). Effects of river engineering on genetic structure of European fish populations. Pages 113- 126 in M. Jungwirth, S. Schmutz and S. Weiss, eds. Fish Migration and Fish Bypasses, Fishing News Books, Vienna (Austria).

Populations of cyprinid fishes from several rivers in Portugal -- Chondrostoma polylepis, France European chub Leuciscus cephalus, roach Rutilus rutilus, Austria nase Chondrostoma nasus, R. rutilus and Greece L. cephalus -- were investigated by allozyme electrophoresis to assess the effects of river engineering on their genetic diversity. No effects of dams on genetic variability were apparent in most places; this may be explained either by the permeability of dams to fish dispersal, by recent dates of isolation, and/or by the fact that the populations were large enough for genetic drift not to take place. However, a change in genotype structure caused by the dams may be suspected in the Lower Rhone. The chub and roach populations of the reservoirs and residual flow stretches show affinity with upstream lentic populations and not with upstream lotic populations as would be expected according to the mean gradient of their habitats. They are unstable populations in which extinction and colonisation from lentic upstream habitats presumably determine genetic structure.