Warty Sea Cucumber, Apostichopus parvimensis

Warty Sea Cucumber, Apostichopus parvimensis. Underwater photograph taken in Mission Bay, San Diego California, January 2019. Photograph and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny:  The Warty Sea Cucumber, Apostichopus parvimensis (Clark, 1913), is a member of the Spiky Sea Cucumber or Stichopodiidea Family. The genus Apostichopus is one of ten genera in this family, and it consists of nine species. In Mexico this species is known as pepino de mar con protruberancias.

Morphology:  Warty Sea Cucumbers are brown in color and covered with numerous small, black-tipped papillae. There are several larger, conical-shaped “warts”, from which they derive their common name. Their bodies are large and cylindrical in shape. The ventral surface is  flattened. All of their feet are located on the ventral surface. They have branched tentacles at their mouth end. Warty Sea Cucumbers reach a maximum of 41 cm (16 inches) in length.

Habitat and Distribution:  Warty Sea Cucumbers reside within mud, rock and sand substrate and are found in tidal pools from the intertidal zone to depths up to 60 m (197 feet). In Mexican waters the Warty Sea Cucumber is a resident of the Pacific but are only found from Bahia Tortugas, Baja California Sur, northward along the central and northwest coasts of the Baja Peninsula.

Diet:  Warty Sea Cucumbers are depositional feeders that crawl along the bottom, using their sticky tentacles to collect detritus and other organic matter, such as bacteria and fungus. This method of feeding redistributes sediment, and therefore contributes to the general ecology.

Predators: Warty Sea Cucumbers are preyed upon by shore birds, crabs, marine mammals, sea stars, and fish such as the Kelp Greenling, Hexagrammus decagrammus and the California Sheephead, Semicossyphus pulcher. They do have the ability to auto-eviscerate their internal organs to distract potential predators. Some members of the family have an annual cycle of auto-eviscerating their digestive tract and gonads to remove sediment build up caused by their feeding process. They regrow these organs in a matter of weeks.

Reproduction: Warty Sea Cucumbers are gonochoric (male or female for life) and reproduce sexually, with external fertilization. The larvae are free-swimming plankton for around twenty-eight days then they settle to the bottom and become benthic. Spawning usually takes place in May and June.

Ecosystem Interactions:  Warty Sea Cucumbers benefit the overall ecosystem by their constant moving and recycling of sea floor sediments. Warty Sea Cucumbers also host a variety of other species, including the Scale Worm, Arctonoe pulchra and the Mottled Pea Crab, Opisthopus transversus. The Mottled Pea Crab lives in the sea cucumbers cloaca where it obtains food and shelter.

Human Interactions:  Warty Sea Cucumbers are an important commercial species. Warty Sea Cucumbers are harvested by divers, usually along with sea urchins. Warty Sea Cucumbers are primarily sold to Asian markets, where they are considered a delicacy. Until regulations went into effect in California in the 1990’s, Warty Sea Cucumber populations began to dwindle in southern California. They have since improved. There is insufficient information to assess their population trends in Baja California. From a conservation perspective the Warty Sea Cucumber is currently considered to be of Least Concern.

Synonyms:  Parastichopus parvimensis and Stichopus parvimensis.