Yellow Rock Crab

Metacarcinus anthonyi

The Yellow Rock Crab, known scientifically as Metacarcinus anthonyi, is a species found along the Pacific coast of North America, from Baja California up to Humboldt Bay in Northern California. It is more commonly encountered in southern regions, particularly around San Pedro. Divers can spot these crabs in rocky areas, typically at depths reaching up to 132 meters, although they are more frequently found at shallower depths, with many records indicating they inhabit areas less than 50 meters deep. Adult Yellow Rock Crabs are distinguishable by their oval, broad carapace, which can reach up to 165 mm in males and 148 mm in females. Their coloration ranges from yellow to brown, with juveniles often appearing darker. A notable feature is their black-tipped claws, which they use to crush prey like echinoderms, snails, and clams. Unlike some other crab species, they do not tend to decorate themselves or have hairy legs, and they lack red spotting on their underside. These crabs play an important role in the ecosystem, serving as prey for various fish species and sea otters. They reach sexual maturity after 10–12 molts, with mating occurring in June shortly after the females molt. For divers, encountering a Yellow Rock Crab can offer a glimpse into the dynamic food web of rocky reef environments. The species is subject to commercial fishing, particularly in Southern California, where it is one of the few crabs to reach the minimum landing size.