|Pacific Blue Mussel|
The Pacific blue mussel has only recently been recognized as a separate species, Mytilus trossulus ("MIH till us TROSS you lus"). It had been considered the same as the Atlantic blue mussel, Mytilus edulis ("ED you lus"), which in fact is also found in some areas of the northeast Pacific. To further complicate matters, another species originally from the Mediterranean area is now being grown in mussel farms in British Columbia. It is found occasionally attached to the Marine Ecology Centre.
Adult Pacific Blue mussels are 3 to 10 cm in length. Despite their common name, some are brown.
The drawing below illustrates the siphons [intake and exhaust], the wormlike foot on the left, and the fibers which attach the mussel to the bottom.
Drawing by Iris Churcher,