Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest). Brown Rock Crab, Red Rock Crab, and Yellow Crab

Species profiles are literature summaries of the taxonomy, morphology, distribution, life history, habitats, and environmental requirements of coastal species of fishes and aquatic invertebrates. They are designed to assist in environmental impact assessment. Rock crab is the common name designating three similar species of edible crabs brown rock crab Cancer antennarius, red rock crab C. productus, and yellow crab C. anthonyl. The three species co-occur in shallow coastal waters throughout the Pacific Southwest region. The yellow crab is most common in southern California on sand substrate, and the red rock crab in northernmost areas on rock or gravel substrates the brown rock crab occurs on rock or sand substrates in all areas. Rock crabs are sought commercially to fill an increasing market demand for whole crabs that approached 2 million pounds annually in 1986. Most of the catch comes from the region of Morro Bay south to Los Angeles, including the Channel Islands. Egg-bearing females are commonly found during winter, although they may occur throughout the year. Rock crabs go through five zoeal stags and one megalopal stage during a larval period that generally requires 90-120 days. Metamorphosis and settlement of the first crab stage is on either sand rock, and crabs may reach maturity within 1-2 years. All three species are predators on a variety of shelled mollusks, but are also considered scavengers. They are a major food for many commercially and recreationally important fishes, as well as for the threatened southern sea otter, Enhydra lutris.