Naturally Kiawah Magazine Volume 41 | Page 51

Sea Cucumbers—Really Cool Animals! From Jane Ellis Sea Cucumbers are really cool animals found in tidal pools, scattered on our beach after storms, and even burrowed in the pluff mud of the Kiawah River. These soft, elongated “cigar” shaped organisms are first cousins to sea urchins, sand dollars, and sea stars all belonging to the group of marine invertebrates called echinoderms. Most echinoderms have radial symmetry, spiny skin, and tube feet but don’t have an anterior (head) and posterior (tail) region. Sea cucumbers have all these traits and a head area with a mouth (most often surrounded by a cluster of retractable tentacles used to collect food), a tubular body, and a rear section with an opening at the end of a long- coiled intestines called the anus. These common benthic (bottom dwelling) animals also have some unusual characteristics. For one, their branched respiratory tubules open through the rear of the body at the anus. Water is pulled (breathed) in and then expelled after gases and excretory products are exchanged. Another interesting feature is that sea cucumbers can “eviscerate” their respiratory tubules, intestine and other internal organs through this opening as a defense mechanism. The mass WINTER/SPRING 2019 • VOLUME 41 of long tangled, sticky threads may contain toxins such as “holothurin”. Not to worry, the sea cucumber can regenerate these body parts in two to six weeks. Although sea cucumbers have no distinct sensory organs, they are very sensitive to touch and can “harden” their bodies and squirt water when picked up by a predator. Sea cucumbers normally move slowly scavenging detritus (decayed organic matter) and plankton for food performing the important environmental task of recycling nutrients. Certain species burrow and extend their tentacles into the current to collect “food” as it passes. In some oceans these animals travel in herds along the ocean floor processing tons of sediments as they move. But they are easy prey for animals not affected by their toxins such as large mollusks, fish, crabs, lobsters and even sea turtles. Besides being a food source, some species are hosts for a variety of flatworms, crabs, snails and small fish. For example, pearlfish are known to inhabit their posterior intestinal tract and can often be seen darting in and out of a sea cucumber’s rear opening. From intertidal zones and shallow seas to the deepest sea floors sea cucumbers can be found in all the world’s oceans. There are over 1,200 species of these invertebrates who are usually four to twelve inches long but the smallest species is less than half an inch in length and the largest up to six feet long. Sea cucumbers have been used as food and medicine for over a thousand years. Today you can find them fresh (raw), dried, smoked, powdered, fried, fermented, in soups and stews especially in Asia, Japan and the Indo-Pacific region. Called “beche- de-mer,” “Trepang,” or “gamat” these animals are considered delicacies and are highly prized—so much so that certain species are over harvested. In the past they were believed to have aphrodisiac and restorative properties. Recently researchers have found that sea cucumbers contain an impressive array of vitamins, minerals and unique bioactive compounds that might have anti-inflammatory, anticancer, anti- hypertension and wound healing actions. Striped sea cucumbers (Thyonella gemmata), Pentamera pulcherrima, and brown or hairy sea cucumbers (Sclerodactyla briarius) are common in our area. NK 49