The scientific name for this very well known species of bivalve (Mytilus edulis) is probably the first one I ever learnt in biology class at school. The Common Blue Mussel, sometimes simply referred to as the Common Mussel is extremely common in many parts of Europe, especially around Atlantic coasts. However, their scientific classification is not that simple, with Blue Mussels actually forming of a group of (at least) three closely related taxa of mussels, known as the Mytilus edulis complex. See here for more information.
In Galicia – where I am currently – (the featured image was actually taken in Southern Ireland) the Blue Mussel is farmed extensively and often grow to impressive sizes. A few years ago while staying in a hotel near Vigo, I was initially quite startled to see these farms from my window, as they looked like an approaching armada of battle ships. You can actually see them on Google Maps here. I have to admit, they are one of my favourite shell fish to dine on in one of the many local sea food restaurants found in our area. Simply steam in sea water or add a bit of white wine, a squeeze of lemon and a knob of butter. Yum!