Yellow Shore Crab, Hemigrapsus oregonensis

Yellow Shore Crab, Hemigrapsus oregonensis. Crab collected out of tidal pool in the greater San Diego, California area, November 2008. Size: 3.0 cm (1.2 inches) x 2.5 cm (1.0 inch).

General information: The Yellow Shore Crab, Hemigrapsus oregonensis, is one of the most common crabs along the Pacific Coast and is a member of the Grapsidae Family (a family which includes the infamous Sally Lightfoot). It is known in Mexico as amarilla congrejo de tierra.

Identification: These crabs are decapod crustaceans with 10 limbs, short eye stalks, powerful claws, and short antennae, with a large shell or carapace covering their bodies. They are characterized by a large squarish carapace that has three teeth following the widely separated fairly large eyes, and hairy walking legs. They vary in color from a uniform dark grayish green to white and mottled patterns. The claws have white tips. Out of water they are faster and more agile than most crabs. The Yellow Shore Crab is sexually dimorphic with the males reaching 3.5 cm (1.4 inches) in length and the females 2.9 cm (1.15 inches). They are most likely confused with the Purple Shore Crab, Hemigrapsus nudus (which have rectangular white spotting on the shell and have red spots on the claws).

Habitat and Range: They are found under rocks high in the intertidal zone especially on muddy or gravelly beaches and in estuaries. They have an extensive range being found from Resurrection Bay, Alaska to as far south as Todos Santos, Baja California Sur.

Diet:  The Yellow Shore Crab is an opportunistic purveyor of smaller animals, a scavenge of diatoms and algae off the surfaces of rocks during nighttime low tides, and a filter-feeder.

Conservation Status:  From a conservation perspective the Yellow Shore 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:   Pseudograpsus oregonensis