GENETIC-STRUCTURE OF POPULATIONS OF 2 SPECIES OF CHTHAMALUS (CRUSTACEA, CIRRIPEDIA) IN THE NORTHEAST ATLANTIC AND MEDITERRANEAN

Protein electrophoresis on starch gels was used to investigate populat ion genetic structure of the barnacles Chthamalus montagui Southward a nd C. stellatus (Poll) over their north-east Atlantic and Mediterranea n ranges. In each species, a single locus exhibited marked differentia tion of allele frequencies between Atlantic and Mediterranean localiti es; in C. stellatus, genetic differentiation between the two basins ha d not previously been noted. In both species, mean heterozygosity per locus appeared higher in the Mediterranean samples than in the Atlanti c, and Mediterranean populations had more alleles at the loci studied. Possible explanations for the differentiation between the Atlantic an d the Mediterranean populations are discussed.