Project Description

It was great finding these California mussel (Mytilus californianus) shell valves on the ocean floor below a large colony.  The California mussel can be distinguished from other species of mussels on the Pacific Northwest coast by having thick valves, strong radial ribs and irregular transverse growth lines, and with adults attaining a much larger size.  This mussel often has areas of its shell eroded, and the interior side of the valves is blue-gray and can have a slightly iridescent appearance.  The California mussel can grow to 10 inches (25 cm) in length, with a range from central Alaska to northern Mexico.