Pacific Rock Crab

Romaleon antennarium

The Pacific Rock Crab, Romaleon antennarium, is a crustacean found along the western coast of North America, from Alaska to Mexico. It has a fan-shaped carapace with eleven teeth on each side of its eyestalks, with the widest point at the eighth or ninth tooth. Its stout chelipeds have distinctive black tips that curve downward. The dorsal surface of adults is uniformly red, while the ventral side is spotted, distinguishing it from the similar red rock crab, which lacks these spots and has less prominent antennae and claws. This species inhabits temperate coastal waters and is commonly found on rocky and soft bottoms, from the very low intertidal zone to depths of 30 meters, although it can be found as deep as 91 meters. It often buries itself in sand or hides under rocks, and it can also be found in bays and estuaries. The Pacific Rock Crab is both a scavenger and a predator, feeding on a variety of small invertebrates. Divers may encounter the Pacific Rock Crab in protected outer coastal areas or offshore. It is not evaluated for conservation status by the IUCN. The species is part of a commercial fishery in California, where it is harvested alongside the yellow and red rock crabs.