''Holothuria fuscocinerea'', the ashy pink sea cucumber, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

sea cucumber Sea cucumbers are echinoderms from the class Holothuroidea (). They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothuria ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Holothuriidae Holothuriidae is a family of sea cucumbers, a type of echinoderm. Description Members of the family Holothuriidae have thick fleshy bodies and several rows of tube feet which are used for moving around and for adhering to the surface. The body ...

. It is placed in the subgenus ''Stauropora'', making its full name ''Holothuria'' (''Stauropora'') ''fuscocinerea''. It is native to shallow water in the tropical and sub-tropical Indo-Pacific.

Description

This sea cucumber has an oval, cylindrical body, flattened somewhat on the underside, and rounded at both ends. It can reach a length of but is a more normal size. The adult weighs between . The mouth is on the underside at the front and is surrounded by twenty short, brown, branched feeding tentacles. The anus is dark brown or black and has no anal teeth, but is surrounded by five white-tipped papillae. There are

Cuvierian tubules Cuvierian tubules are clusters of fine tubes located at the base of the respiratory tree in some sea cucumbers in the genera '' Bohadschia'', ''Holothuria'' and '' Pearsonothuria'', all of which are included in the family Holothuriidae. The tubule ...

in this species. The skin is soft, thick and wrinkled, often with sand adhering to it. It varies in colour, the upperside usually being greyish or brownish, while the underside is a dirty white. There is often a series of dark bars in the transverse wrinkles.

Distribution

''H. fuscocinerea'' has a widespread distribution in the Indian and Pacific Oceans. Its range extends from East Africa and the Red Sea to southern Japan, northern Australia and Central America. It is typically found on coral rubble and soft sediments, and among

seagrass Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the orde ...

es. It usually occurs at depths of less than but can occur down to .

Ecology

''H. fuscocinerea'' is a

detritivore Detritivores (also known as detrivores, detritophages, detritus feeders, or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, ...

and feeds at night, sifting through the sediment with its feeding tentacles, swallowing the sediment and extracting the bacteria and organic material it contains, while the sand passes on through its gut. Breeding takes place in the hot season. The sexes are separate in this species; they climb to an elevated location before releasing their

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce t ...

s into the

water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...

. Females produce an average of around three million eggs. The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e are pelagic and drift with the

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

. When sufficiently developed they settle on the seabed and undergo

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

into juveniles. Like other sea cucumbers, the tissues contain

saponin Saponins (Latin "sapon", soap + "-in", one of), also selectively referred to as triterpene glycosides, are bitter-tasting usually toxic plant-derived organic chemicals that have a foamy quality when agitated in water. They are widely distributed ...

s which are distasteful and toxic to fish, causing

haemolysis Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...

of the

red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

s, which can be fatal. The skin periodically flakes off in little shreds, and fish can sometimes be seen nibbling these. This

desquamation Desquamation occurs when the outermost layer of a tissue, such as the skin, is shed. The term is . Physiologic desquamation Keratinocytes are the predominant cells of the epidermis, the outermost layer of the skin. Living keratinocytes reside in ...

may be a method for the sea cucumber to rid itself of metabolic waste.

Status

This is a common species of sea cucumber. It is of little commercial importance to fisheries, but is sometimes used for food, especially in China, the Philippines and Malaysia. It may be used more for this purpose if other more palatable species become depleted. The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has assessed its conservation status as being of "

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

References

{{Taxonbar, from=Q2449315 Holothuriidae Animals described in 1833