Striped Shore Crab, Pachygrapsus crassipes

Striped Shore Crab, Pachygrapsus crassipes. Crab collected from within the Mangroves of Agua Verde, Baja California Sur, March 2019.  Size:  4.8 cm (1.9 inches). Collection and photography courtesy of Barry Mastro, Escondido, California.

General information: The Striped Shore Crab, Pachygrapsus crassipes, is a member of the Grapsidae Family of Shore Crabs. They are osmoregulators, capable of withstanding both hypo and hyper-osmotic environments.

Identification: Striped Shore Crabs are easily recognized by their prominent transverse green striations on the dorsal surface and by having only two teeth laterally behind the eyes. The carapace is a dark red to reddish-green and the chelae are strong with deep red and purple veining. They are sexually dimorphic with males reach a maximum width of 4.8 cm (1.9 inches) and the females 4.1 cm (1.6 inches). The Striped Shore Crab is very similar to the Purple Shore Crab, Hemigrapsus nudus and the Yellow Shore Crab, Hemigrapsus oregonensis (both of which have three lateral teeth and lack transverse striations).

Habitat and Range: The Striped Shore Crabs are abundant in rocky intertidal areas and can be found on land about half of the time. They are active during daylight hours. They are most commonly found along the west cost of California and Oregon, In Mexico the Striped Shore Crabs are found along the west coast of Baja and throughout the Sea of Cortez.

Diet: The Striped Shore Crabs forage both in and out of water on algae and diatoms which they scrap off rocks as-well-as dead animals and small intertidal invertebrates. In turn they are preyed upon by anemones, shore birds, fishes and raccoons.

Conservation status:  From a conservation perspective the Striped 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: Grapsus eydouxi and Leptograpsus gonagrus