Allozymes and morphometric characters of three species of Mytilus in the northern and southern hemispheres

Many authors have considered the common mussels in temperature waters of the Northern and Southern Hemispheres to be a single cosmopolitan species, Mytilus edulis . Others have divided these mussels into several subspecies or species. Samples of mussels were collected from 36 locations in the Northern Hemisphere and nine locations in the Southern Hemisphere. Electrophoretic evidence from eight loci indicates that the Northern Hemisphere samples consist of three electrophoretically distinguishable species: M. edulis from eastern North America and Western Europe; M. galloprovincialis Lamarck, 1819 from the Mediterranean Sea, western Europe, California, and eastern Asia; and M. trossulus Gould, 1850 from the Baltic Sea, eastern Canada, western North America and the Pacific coast of Siberia. Mussels from Chile, Argentina, the Falkland Islands and the Kerguelen Islands contain alleles characteristic of all three Northern Hemisphere species.