Blue Mussel (Mytilus edulis)

Other Names: Pacific blue mussel, common blue mussel

Description: There are three species of mussels in the Mytilus genus found on the West Coast that are difficult to differentiate, but the most commonly found at Haystack Rock are the M. edulis. Blue mussels are a small species of mussel, typically less than 7cm long. They are usually a dark blue or black color and can look like young California mussels. One way to differentiate the two species is to look at the texture of their shells; blue mussels have a relatively smooth surface while their larger relatives have vertical groves extending from the base of each shell.

Habitat: Blue mussels range from Alaska to Northern Mexico. They attach to substrate like rocks or docks in the intertidal zone. At Haystack Rock, blue mussels live within the California mussel beds on large boulders in the middle of the intertidal zone.

Diet: As filter feeders, blue mussels pump water through their body so that they can capture plankton.

Tide Pool Tidbits:

• California mussels and blue mussels packed closely together create a “bed” that functions as a habitat for many other species of plant and animal.

• Mussels are an important food source for ochre sea stars.

• Blue mussels are edible and are grown on commercial farms in China and Japan.

Reference: Biodiversity of the Central Coast