The Mediterranean Mussel (Mytilus galloprovincialis) is native to the Mediterranean, Black, and Adriatic Seas, but has spread (mostly via ballast water and ship hull fouling) to many other regions worldwide. These mussels usually occur in the low intertidal zone of exposed rocky coasts with relatively high wave energy, although in their native range they are also found growing in dense patches on the sandy-muddy bottoms of brackish lagoons (Ceccherelli and Rossi 1984). Although this species is cultivated as food for humans in some parts of Asia, in most of its non-native range it has become a nuisance species, displacing natives, and the IUCN/SSC* Invasive Species Specialist Group has nominated Mytilus galloprovincialis as among the 100 "World's Worst" invaders.
*International Union for Conservation of Nature, Species Survival Commission
Native range (alphabetical by country): Algeria, Australia, Bosnia and Herzegovina, Bulgaria, Croatia, Egypt, Europe, France, Greece, Italy, Libyan Arab Jamahiriya, Macedonia, Morocco, Portugal, Romania, Russian Federation, Spain, Tunisia, Turkey, Ukraine
"Alien" range (alphabetical by country/region): Africa, Australia, Canada, Democratic People's Republic of Korea, Hong Kong, Ireland, Japan, Mediterranean, Mexico, Namibia, Netherlands, Republic of Korea, South Africa, United Kingdom, United States (including Hawaii)
Marine and estuarine.
“In its native range, M. galloprovincialis can be found from exposed rocky outer coasts to sandy bottoms (Ceccherelli and Rossi 1984). As an invader it typically requires rocky coastlines with a high rate of water flow...(Carlton 1992)."
Because the shells of Mytilus species are similar and can vary depending on their environment, it’s difficult or impossible to visually distinguish M. galloprovincialis from Mytilus edulis and Mytilus trossulus. Furthermore, M. galloprovincialis and M. trossulus can hybridize (Suchanek et al. 1997). Genetic analyses are necessary to make a positive identification.
“Mytilus galloprovincialis is dark blue or brown to almost black. The two shells are equal and nearly quadrangular. The outside is black-violet coloured; on one side the rim of the shell ends with a pointed and slightly bent umbo while the other side is rounded, although shell shape varies by region. It also tends to grow larger than its cousins, up to 15cm, although typically only 5-8cm.” (IUCN/SSC Invasive Species Specialist Group (ISSG))
