Warty sea cucumber

Natural History

The warty sea cucumber—shaped like a long cylinder and soft as a feather pillow—bears little resemblance to its close relatives the sea stars and sea urchins. The name "warty" comes from the numerous black-tipped projections covering the sea cucumber's brownish skin. Even though tube feet line its underbody, a sea cucumber is reluctant to move. When necessary, however, it can creep three feet in 15 minutes—speedy for this animal.

An intestinal tract connects the mouth and anus on opposite ends of the warty sea cucumber's body. A respiratory tree—a collection of thin-walled tubes—stems from this tract. The sea cucumber draws water through its anus into the tree where respiration takes place. It then forcefully expels the water.

Conservation

In California, commercial fisheries seek two species of sea cucumbers—warty and California—that are shipped to Asian markets both here and overseas. Commercial fisheries need a permit to fish for sea cucumbers, but there are no restrictions on the number of animals caught. Worldwide, many sea cucumber fisheries have collapsed as a result of overfishing. 

The demand for sea cucumbers in Asian markets, where people value them as a food and as a medicine, is large. To fill the void, people began fishing for sea cucumbers in the waters near the Galapagos Islands in 1988. In 2001, the Inter-institutional Management Authority agreed on regulations that allow resident fishermen to catch four million sea cucumbers each year in established fishing zones near islands.

Cool Facts

Each fall, the warty sea cucumber finds a secure place to hide while its viscera—including the gonads, circulating system, and respiratory tree—atrophy. Within two to four weeks, the viscera regenerate. 

If a warty sea cucumber is roughly handled or finds the water too warm during this season, it forcibly spews out its viscera through its anus in a process called evisceration. 

Warty sea cucumbers and their related species are sometimes called the "earthworms of the sea," as they cultivate the seafloor in much the same manner as earthworms cultivate the soil. 

Oral tube feet around the mouth are covered with a sticky mucus that traps food particles from the seafloor's sediment and mud. In areas where overfishing has reduced the population of sea cucumbers, the seafloor hardens, thus destroying a habitat for other bottom-dwelling creatures.