About
Native to the Mediterranean coast and the Black and Adriatic Seas it has now spread widely around the world and is well established here in Australia locally it has interbred with our local species (native Blue Mussel) to a point it is now the more dominant species.It 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.