The Mediterranean mussel, scientific name Mytilus galloprovincialis, is a species of bivalve, a marine mollusc in the family Mytilidae. It is an invasive species in many parts of the world, and also an object of aquaculture.
Mytilus galloprovincialis is one of the three principal, closely related species in the Mytilus edulis complex of blue mussels, which collectively are widely distributed on the temperate to subarctic coasts of both the Northern and Southern Hemispheres, and often are dominant inhabitants on hard substrates of the intertidal and nearshore habitats. M. galloprovincialis will often hybridize with its sister taxa, the closely related Mytilus edulis and Mytilus trossulus, when they are found in the same locality. M. galloprovincialis is considered the most warm-water-tolerant species of the three, and has the most southerly distribution in Europe and North America.
In the northern Pacific the species is found along the coast of California, where it was introduced from Europe by human activity in the early 20th century, and also in the Puget Sound region of Washington State, where it has been subject to aquaculture. It is also present as an invasive species on the Asian coast throughout Japan, including Ryukyu Islands, as well as in North Korea  and around Vladivostok in Russia.
Mytilus galloprovincialis is also present as a native lineage in parts of the Southern Hemisphere. In addition there are populations introduced from the north recently with human activity. These lineages are distinguished by genetic characters. No original Mytilus populations lived in southern Africa, but the Mediterranean mussel was introduced from Europe in 1984 and is now the dominant low intertidal mussel on the West Coast. The distribution spans an area from the Namibian border to Port Alfred, intertidally to just below the low tide border.  M. galloprovincialis is also found in New Zealand, Australia and South America.
This animal grows up to 140 mm in length. It is a smooth-shelled mussel with a slightly broader base than that of the black mussel, with which it is often confused in South Africa. Its shell is blue-violet or black, but may shade to light brown.
The Mediterranean mussel is a filter feeder. It is rare subtidally, which is an alternate means of distinguishing it from the black mussel in South Africa.
- Mytilus galloprovincialis (mollusc) Global Invasive Species Database. issg.org
- Thomas J. Hilbish, Pamela M. Brannock, Karlie R. Jones, Allison B. Smith, Brooke N. Bullock and David S. Wethey (2010) Historical changes in the distributions of invasive and endemic marine invertebrates are contrary to global warming predictions: the effects of decadal climate oscillations. Journal of Biogeography 37:423–431.
- Mytilus galloprovincialis www.nies.go.jp
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