<p style="color: rgb(0, 0, 0); font-family: "Times New Roman"; font-size: medium;"><strong>Sea cucumbers</strong> are <a href="http://en.wikipedia.org/wiki/Echinoderm" title="Echinoderm">echinoderms</a> from the <a href="http://en.wikipedia.org/wiki/Class_(biology)" title="Class (biology)">class</a> <strong>Holothuroidea</strong>. They are <a class="mw-redirect" href="http://en.wikipedia.org/wiki/Marine_animal" title="Marine animal">marine animals</a> with a leathery skin and an elongated body containing a single, branched<a href="http://en.wikipedia.org/wiki/Gonad" title="Gonad">gonad</a>. Sea cucumbers are found on the sea floor worldwide. The number of <strong>holothurian</strong><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English" title="IPA for English">/</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">ˌ</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">h</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">ɒ</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">l</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">ɵ</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">ˈ</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">θj</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">ʊər</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">i</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">ə</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English#Key" title="IPA for English">n</a><a href="http://en.wikipedia.org/wiki/Help:IPA_for_English" title="IPA for English">/</a> species worldwide is about 1,717 with the greatest number being in the Asia Pacific region. Many of these are gathered for human consumption and some species are cultivated in aquaculture systems. The harvested product is variously referred to as <em><a href="http://en.wikipedia.org/wiki/Trepanging" title="Trepanging">trepang</a></em>, <em>bêche-de-mer</em> or <em>balate</em>. Sea cucumbers serve a useful role in the marine ecosystem as they help recycle nutrients, breaking down<a href="http://en.wikipedia.org/wiki/Detritus" title="Detritus">detritus</a> and other organic matter after which bacteria can continue the degradation process.</p> <p style="color: rgb(0, 0, 0); font-family: "Times New Roman"; font-size: medium;">Like all echinoderms, sea cucumbers have an <a href="http://en.wikipedia.org/wiki/Endoskeleton" title="Endoskeleton">endoskeleton</a> just below the skin, calcified structures that are usually reduced to isolated microscopic <a href="http://en.wikipedia.org/wiki/Ossicle_(echinoderm)" title="Ossicle (echinoderm)">ossicles</a> (or sclerietes) joined by connective tissue. In some species these can sometimes be enlarged to flattened plates, forming an armour. In <a class="mw-redirect" href="http://en.wikipedia.org/wiki/Pelagic" title="Pelagic">pelagic</a> species such as <em><a href="http://en.wikipedia.org/wiki/Pelagothuria_natatrix" title="Pelagothuria natatrix">Pelagothuria natatrix</a></em>(Order <a href="http://en.wikipedia.org/wiki/Elasipodida" title="Elasipodida">Elasipodida</a>, family <a href="http://en.wikipedia.org/wiki/Pelagothuriidae" title="Pelagothuriidae">Pelagothuriidae</a>), the skeleton is absent and there is no calcareous ring.</p>