Genetic cohesiveness among populations of Concholepas concholepas (Gastropoda, muricidae) in Southern Chile

Six local populations of the marine gastropod Concholepas concholepas (‘loco’) from four regions in southern Chile were examined genetically by starch gel electrophoresis. Percent polymorphic loci, number of alleles per locus and average heterozygosity levels are low relative to other mollusc species. Genetic substructuring as derived from F st values, indicated reduced levels of demic subdivision suggesting larval interchange and concomitant high levels of gene flow that prevent differentiation by drift within or between regions. No positive correlation between the genetic and geographic distances was detected. Contrary to previous claims, our results provide no basis for recognizing different genetic units in southern populations at any spatial scale. Larval dispersal is large enough to replenish the genetic variation lost in overfished local stocks, but probably not large enough to compensate the demographic consequences of continuous overfishing.