sea cucumber

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sea cucumber,

any of the flexible, elongated echinoderms belonging to the class Holothuroidea. Although sea cucumbers have the basic echinoderm radial symmetry (see EchinodermataEchinodermata
[Gr.,=spiny skin], phylum of exclusively marine bottom-dwelling invertebrates having external skeletons of calcareous plates just beneath the skin. The plates may be solidly fused together, as in sea urchins, loosely articulated to facilitate movement, as in sea
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), they do not have arms like starfish. Instead the oral-anal distance is greatly increased, resulting in the typical cucumber-shaped body.

Sea cucumbers live with one side facing permanently down. Like other echinoderms, sea cucumbers have a water-vascular system; the locomotor tube feet are concentrated in three areas on the ventral, or under, side, in some species forming a muscular, creeping sole. Some species burrow in sand or mud and have lost all tube feet. The leathery body wall contains minute, scattered skeletal ossicles, or bonelike plates; a few species have an armor of close-set plates.

Some species eat bottom material, while others use tube feet modified as branched oral tentacles to capture particles or plankton and transfer them to the mouth. Most sea cucumbers have highly branched tubes called respiratory trees attached to the intestine near the anus. Water is pumped in and out, facilitating respiratory exchange and excretion. In some species, branches called tubules of Cuvier, attached to or near the bases of the respiratory trees, are ejected when the organism is attacked; they swell and become sticky, entangling the pursuer. Many sea cucumbers eject most of the internal organs when sufficiently irritated, later regenerating a new set.

Sea cucumbers have a single, branched gonad. Eggs are usually expelled into the sea where, after fertilization, free-swimming larvae develop. After a second larval stage, metamorphosis occurs and the adult body shape appears.

Sea cucumbers occur in all seas and at all depths. Most do not exceed 1 ft (30.5 cm) in length, but Stichopus variegatus from the Philippines may reach 3 ft (91 cm) in length. Known as trepang or bêche-de-mer, a number of species are caught along warm coasts of Australia, the East Indies, and some Pacific island nations. They are dried and sold, mainly to markets in E Asia, for use as food or in traditional medicine. Sea cucumbers are classified in the phylum Echinodermata, class Holothuroidea.

sea cucumber

[′sē kyü‚kəm·bər]
(invertebrate zoology)
The common name for the echinoderms that make up the class Holothuroidea.
References in periodicals archive ?
The mean density value within the West Isabela macrozone was then compared with the sea cucumber reference points defined in the Fishery Chapter of the Management Plan for the Galapagos Marine Reserve (GMR) (Castrejon et al.
4% has been reported for HD of other sea cucumber species on the basis of the more rigorous comparison of HD with muscle from the same body wall (Takemae et al.
Swimming sea cucumbers (Echinodermata: Holothuroidea): A survey, with analysis of swimming behavior in four bathyal species.
In October, Saudi border guards detained two fishing tourist groups carrying 566 sea cucumbers at fishing harbors on the Tabuk coast, spokesman of the Tabuk border guards said.
Listed under Schedule I of the Wildlife Protection Act, the sea cucumber, an endangered species, is banned to harvest.
Seagrass Thalassia hemprichii and Sea cucumber Holothuria atra were collected from Northern corniche of Jeddah and Southern corniche of Jeddah, respectively (Fig.
Results: The results exhibited that sea cucumber saponin, dacarbazine, and coadministration of saponin-dacarbazine inhibited the proliferation of melanoma cells in a dose and time dependent manner with [IC.
A research to study chemical compound in sea cucumber which is glycosides found significant activity with satisfactory OB (OB z-score: 40%) and favorable DL properties (DL z-score: 0.
The chemical constituents and medicinal uses of this species had not been previously described until we recently investigated the anti-glioma constituents of this sea cucumber and discovered a novel saponin moebioside A (Sap.
They go down to a depth of up to 20 meters to harvest marine products including abalone, conch, shellfish, and sea cucumber.
The student then realised items worth hundreds of pounds, including a valuable sea cucumber, were missing.
Key words: sea cucumber biochemical composition essential amino acid total fatty acids.