Mediterranean Mussel, Mytilus galloprovincialis
The Mediterranean mussel, Mytilus galloprovincialis, is a species of bivalve, a marine mollusk belonging to the family Mytilidae. It’s an invasive species in many areas of the world as well as an object of aquaculture.
Mytilus galloprovincialis has the potential to grow up to 140 millimeters in length. The shell is smooth with a slightly broader base than that of the black mussel, with which it’s often confused with in South Africa. The coloration of the shell is a blue-violet or black, but may shade to a light brown.
This mollusk is one of the three principal, closely related species in the Mytilus edulis complex of blue mussels, which together, are widely distributed on the temperate to sub arctic coasts of both the Northern and Southern Hemispheres, and frequently are dominant inhabitants on hard substrates of the intertidal and near shore habitats. It will often hybridize with its sister taxa, the closely related Mytilus edulis and Mytilus trossulus, when they’re found in the same area. This mollusk is considered to be the most warm-water-tolerant species of the three, and has the most southerly distribution in North America and Europe.
Within Europe, Mytilus galloprovincialis can be found in the Mediterranean and Black Seas, and on the Atlantic coasts, in Portugal, north to France, and the British Isles. Within the northern Pacific, this species can be found along the coast of California, where it was introduced via human activity in the early 20th century, and also in the Puget Sound region of Washington State, where it has been subjected to aquaculture. It’s also present as an invasive species on the coast of Asia throughout Japan, including Ryukyu Islands along with North Korea and around Vladivostok in Russia.
This mollusk is also present as a native lineage in some portions of the Southern Hemisphere. Additionally, there are populations introduced from the north recently with human activity. These lineages are discriminated by genetic characters. No original Mytilus populations resided 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. Its distribution covers an area from the Namibian border to Port Alfred, intertidally to just below the low tide border. You can also find this mollusk in New Zealand, South America, and Australia.
Image Caption: Mediterranean mussel (Mytilus galloprovincialis) shell. Credit: Andrew Butko/Wikipedia (CC BY-SA 3.0)