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.

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sea cucumber

[′sē kyü‚kəm·bər]
(invertebrate zoology)
The common name for the echinoderms that make up the class Holothuroidea.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Key words: sea cucumber biochemical composition essential amino acid total fatty acids.
In Malaysia,the sea cucumbers have great value for their medicinalproperties and also as culinary delicacies [2,3].
Flammang, "Maintaining the line of defense: regeneration of cuvierian tubules in the sea cucumber Holothuria forskali (Echinodermata, Holothuroidea)," The Biological Bulletin, vol.
Sea cucumber fisheries in Alaska, British Columbia, and Washington generally occur in the fall, and are managed as rotational fisheries to minimize assessment and management costs (Hebert 2014, Carson et al.
According to Article 1 of the decision (No 25/2019), fishing of sea cucumbers in all Omani fishing waters is banned from March 27, 2019 for two years.
After confirming normality and homogeneity of variances using Kolmogorov-Smirnov and Levene's tests, respectively, analysis of variance (ANOVA) was carried out to compare sea cucumber lengths across sites and habitats.
Sea cucumbers are classified as endangered species and their harvest is banned under the Wildlife Protection Act.
These data have ecological relevance as in holothurians they can be linked to the reproductive effort and long-term success of the populations (Watanabe et al., 2012), and also have been used as indicators of fishing yields of the brown sea cucumber (Herrero-Perezrul & ReyesBonilla, 2005).
Sea cucumbers are marine animals found on the sea floor, with long, elongated bodies and leathery skin.
Holothuria leucospilota or locally known as Patola or bat puntil is currently considered as the most abundant sea cucumber species in Malaysia [1].
In a pioneer work, Ebert (1978) studied growth of the sea cucumber known as the lolly fish (Holothuria atra) by tagging the plates of their calcareous rings with tetracycline.