GENETICS OF INDIGENOUS AND TRANSPLANTED POPULATIONS OF PECTEN-MAXIMUS - NO EVIDENCE FOR THE EXISTENCE OF SEPARATE STOCKS

Genetic variation at eight polymorphic enzyme loci was investigated in 13 populations of the scallop Pecten maximus (L.) from a number of sites in Scotland, UK and Brittany, France. Two of the populations had initially been transplanted, as spat, to Brittany from Scottish and Irish collection sites. In common with other studies of marine bivalves, an overall deficiency of heterozygotes was observed, but genotype frequencies of transplanted populations were generally in agreement with the Hardy-Weinberg model indicating little post-transplant selection. There was high genetic similarity among all the populations surveyed and no overall differences between the Scottish and Brittany samples. The results are discussed in relation to contrasting evidence, derived from studies on the reproductive cycle of P. maximus and the genetics of Aequipecten (Chlamys) opercularis (L.), which suggests that the Scottish and Brittany scallop populations are, nevertheless, genetically distinct.