California Sea Cucumber, Apostichopus californicus

California Sea Cucumber, Apostichopus californicus. Length: 15 cm (5.9 inches). Sea Cucumber collected from coastal waters off San Diego, California, August 2010.

California Sea Cucumber, Apostichopus californicus. Length: 18 cm (7.1 inches). Sea Cucumber collected from coastal waters off San Diego, California, July 2013.

Phylogeny:  The California Sea Cucumber, Apostichopus californicus (Stimpson, 1857), is a member of the Stichopodidae Family of Spiky Sea Cucumbers. The Apostichopus Genus is one of ten genera in the Stichopodidae Family, and there are nine species in the Apostichopus Genus. They are also known as the Giant Sea Cucumber and in Mexico as Pepino de mar California. The genus name Apostichopus comes from the Greek words meaning “away from row-feet”. This name is to distinguish this genus from the stichopus (row-feet) sea cucumbers. Apostichopus sea cucumbers lack certain spicules (bony structures) that are found in Stichopus sea cucumbers.

Morphology:  The California Sea Cucumber is covered with reddish-brown, white or yellow leathery skin. Their bodies are large and cylindrical with a flattened ventral surface. The mouth is surrounded by 20 retractable tentacles that are utilized to procure food. They are covered with large, stiff, conical papillae that have red tips and are lighter in color than the rest of the body. There are five rows of tube feet along the ventral surface that extend from the mouth to the anus. California Sea Cucumbers are the largest Sea Cucumbers on the Pacific Coast and reach 5.0 cm (2.0 inches) in width, 50 cm (19.7 inches) in length, and 225 grams (0.5 lbs.) in weight. The California Sea Cucumber can be confused with the Warty Sea Cucumber, Apostichopus parvimensis. However, this species is differentiated by a chestnut brown body and pale ventral side. The tips of the papillae are black unlike the red-tipped papillae of the California Sea Cucumber.

Habitat and Distribution:  The California Sea Cucumber is found on rocks, mud, and sand substrates. They live in the intertidal zone, and to depths up to 250 m (820 feet). They are most abundant in areas with moderate currents and bedrock, boulders, and cobbles. The California Sea Cucumber is a temperate to subtropical Eastern Pacific species that has a limited range in Mexican waters of the  Pacific Ocean being only found from Cedros Island, Baja California, northward along the central and northwest coasts of  the Baja Peninsula.

Diet:  The California Sea Cucumber is a solitary, nocturnal animal, that emerge to scavenge on organic detritus and small organisms. They can also take up nutrients via the anus.

Predators:  The California Sea Cucumber are preyed upon by crabs, fish, humans, sea otters, and sea stars. As a defense mechanism the California Sea Cucumber has the ability, when threatened, to expel its organs through its anus to distract predators. They can re-grow nearly all of their internal organs fairly quickly.

Reproduction: California Sea Cucumbers reach sexual maturity at four years Reproduction involves separate sexes with external fertilization with each female releasing thousands of eggs. Metamorphose of larvae into a sea cucumber occurs in a couple of weeks. Younger sea cucumbers often appear more pale in color and are thinner.

Ecosystem Interactions:  California Sea Cucumbers are known to host multiple parasites including: bacteria, protozoan ciliates,  the shell-less snail, Enteroxenos parastichopoli, and flatworms. The California Sea Cucumber has a commensal relationship with the Red Commensal Scale Worm, Arctonoe pulchra, and the pea crab, Opisthopus transversus.

Human Interactions: California Sea Cucumbers are fished by commercial and artisanal fishermen and sold commercially. They are caught by divers and by trawling. They are also raised by aquaculture. From a conservation perspective  the California Sea Cucumber is currently considered to be of Least Concern with stable, widely distributed populations.

Synonyms:  Holothuria californica, Parastichopus californicus and Stichopus californicus.