Blue Mussel (Mytilus edulis):

Blue Mussels are a species of mussel native to the North Atlantic & Pacific. They are frequently found in intertidal zones across the Northern Hemisphere. Their shell is triangular, as well as elongated, with rounded edges. They are a deep shade of blue or black. Individuals will sustain themselves by straining marine microorganisms from the water column. They will also strain pollutants, making the water column cleaner.