ON THE OCCURRENCE OF MYTILUS-GALLOPROVINCIALIS LMK ON THE NW COAST OF THE IBERIAN PENINSULA

The blue mussel Mytilus edulis L. and its southern relative, M. galloprovincialis Lmk., are two forms of mussel that live and are cultivated on the coasts of Europe. Up to date, the type or types of mussel that exist on the Atlantic coast of the Iberian Peninsula have not been clearly determined even though the N.W. corner of this region (Galician Rias) has the highest mussel production in the world. Diagnostic morphological characters (length of anterior adductor muscle scar and size and shape of the hinge plate) and diagnostic enzyme-gene polymorphisms (esterase-D, leucine aminopeptidase-1, octopine dehydrogenase and mannose phosphate isomerase) for M. edulis and M. galloprovincialis were investigated in samples of mussel populations (wild and cultivated) collected from N.W. Iberian Peninsula coastal sites. Evidence from both morphological variation and enzyme polymorphisms indicates that M. galloprovincialis commonly occurs on the N.W. Iberian Peninsula. On the other hand, no evidence for the occurrence of M. edulis was found. The results are discussed in relation to the geographical distribution of both types of Mytilus on European coasts. © 1990.