Genetic and morphological variability in roach Rutilus rutilus, from Austria

Seven samples of roach (Rutilus rutilus L.) from the Austrian section of the Danube river, the Drau river and lake Wallersee were examined to study possible population genetic effects of anthropogenic habitat modification and subdivision. Genetic variability was assessed using electrophoretic variation of 11 enzyme systems coded by 14 gene loci. Genetic variation of roach was remarkably high, and was mainly located within samples while differences between them were weak. Morphometric analyses of conventional external measurements revealed considerable morphological variation within samples. Significant differences between samples mainly involved body depth and fin size, but did not allow adaptive ecomorphological interpretations in several cases. The comparison of morphological and genetic variation showed no significant correlations but was limited by the narrow range of heterozygosity estimates.