Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest) California Sea Mussel and Bay Mussel

Abstract : Species profiles are literature summaries of the taxonomy, morphology, distribution, life history, and environmental requirements of coastal aquatic species. They are prepared to assist in environmental impact assessment. The California sea mussel, Mytilus californianus, and the bay mussel, M. edulis, are commonly collected for bait. Some commercial landing and aquaculture occurs at a very low level of production. Both species are distributed along the California coast; the sea mussel is more commonly found on intertidal coastal rocks and the bay mussel on pilings and other hard substrates in bays and estuaries. The eggs of both species develop into a trochophore stage in 12-24 hours afer fertilization, and the planktonic larval stage lasts 3-4 weeks. Sexual maturity can occur in one year. Spawning of the sea mussel occurs sporadically throughout the year; the bay mussel spawn in central California in late fall and winter. Maximum length is 120-150 mm for the bay mussel and 200- 250 mm for the sea mussel. Both species are regarded as unsafe to eat from May 1 to October 31 due to the possible presence of paralytic shellfish poisoning. Keywords: Life cycles, Fisheries, Mussels, Aquaculture, Feeding habits, Growth physiology, Estuaries, Salinity, Ecological role, Commercial fishery, Sport fishery, Ecological requirements, Species profiles.