Red Rock Crab, Cancer productus

Red Rock Crab, Cancer productus, Female. Crab caught off a pier in Bandon, Oregon in a crab trap, August 2009. Size: 15 cm (5.9 inches) x 8.7 cm (3.4 inches).

Red Rock Crab, Cancer productus, Male. Crab caught off a pier in Bandon, Oregon in a crab trap, August 2009. Size: 16 cm (6.3 inches) x 9.1 cm (3.6 inches).

General information: The Red Rock Crab, Cancer productus, is a common member of the Cancridae Family which includes the Rock Crabs many of which are favorite foods of humans. In Mexico they are known as jaiba del Pacifico. They are not sold commercially due to their small size but they are a target of sports fishermen and provide a delicious food. Red Rocks have been found in fossil records and were a mainstay of Native Americans. They have life spans between five and seven years.

Identification: The Red Rocks have a strong, thick, fan shaped carapace with knobby edges. They are dark red to bright red on top and a yellowish white on the underside. Juveniles come in a variety of colors and patterns. They have four pairs of walking legs and one pair of claws. The claws are exceedingly strong, black tipped, thick, with tooth-like bumps. A male crab has a narrow triangular abdomen while the female and a much wider and more oval abdomen. The Red Rock Crab reach a maximum width of 15 cm (5.9 inches). They can be confused with the Pacific Rock Crab, Cancer antennarius (spotted undersides, haired legs and large antennae).

Habitat and Range: The Red Rock Crabs are found over hard substrates including rocks, pilings and other structure within large estuaries, close to the open ocean, at depths up to 250 feet. They can also be found in tidal pools near protective rock structure in the lower estuary and in near shore areas. They are not found over sandy or muddy bottoms because they lack the gill straining apparatus to rid themselves of these materials. The Red Rock Crab ranges from Alaska to Isla San Martin (San Quintin), Baja California but populations are significantly diminished south of Monterey, California.

Diet: Red Rock Crabs are a major predator of the highly invasive Green Crab, Carcinus maenas, and the two species rarely exist in the same habitats. They also eat barnacles, bivalves, smaller crabs and dead fish. In turn they are preyed upon by large fish, octopuses, and marine mammals.

Conservation Status: From a conservation perspective the Red Rock Crab has not been formally evaluated. However, they are common and of limited interest to most and should be considered to be of Least Concern.

Synonyms: Cancer brewerii and Cancer perlatus