Cabrillo Marine Aquarium

California Mussel

Mytilus californianus


Fun Facts

    While feeding, a mussel filters 2 to 3 quarts of water per hour.

    A California mussel grows to full size in about three years.



  The California mussel lives on rocky shores and attaches to the rocks by fibers called byssal threads. Mussels can out-compete other animals and plants for space. However, they do not take over completely; other predators, such as lobsters, crabs and sea stars eat them and keep their numbers in control. Algae, barnacles and other species can then use the cleared living space. Mussels filter the sea water and feed on fine organic detritus and living plankton. They grow to be about 5 inches.
Rocky shore organisms are at risk from coastal development and pollution, including waste oil and agricultural runoff. Some areas are also in danger of being "loved to death" by visitors. Tread lightly as you explore the rocky intertidal to avoid crushing algae and animals, and never take organisms from their habitat.
California mussels are usually found at the Aquarium in tank number 1 and an exhibit on the feeding habits of mussels can be found near the Hunters of the Rocky Shore Room.