Holothuria spinifera | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Echinodermata |
Class: | Holothuroidea |
Order: | Holothuriida |
Family: | Holothuriidae |
Genus: | Holothuria |
Species: | H. spinifera |
Binomial name | |
Holothuria spinifera | |
Holothuria spinifera, the brown sandfish, is a species of sea cucumber in the family Holothuriidae. It is placed in the subgenus Theelothuria, making its full name Holothuria (Theelothuria) spinifera. [2] In India it is known as cheena attai or raja attai. It lives in tropical regions of the west Indo-Pacific Ocean at depths ranging from 32 to 60 metres (105 to 197 ft). It is fished commercially to produce beche-de-mer .
Holothuria spinifera has a cylindrical body, dark brown on the upper side and pale brown beneath. The skin is densely covered with sharp conical protuberances. [3] It can grow to a length of 30 centimetres (12 in). [4]
Holothuria spinifera is a scavenger, sifting through the sediment on the seabed with its tentacles. It usually spends the day buried in the sediment and emerges at night. [4]
Research has been undertaken into the reproduction and life cycle of Holothuria spinifera with a view to breeding it commercially for aquaculture or for sea ranching. In a study in India, several adults were caught by hand and placed in a tank. Spawning took place spontaneously with a male liberating sperm in a white strand. A female responded by producing a spurt of eggs that were fertilized in the water column. The larvae were pelagic and developed rapidly, being fed on microalgae for the first ten days. For the next four days they passed through the non-feeding, barrel-shaped, doliolaria stage and moved about in the tank. They then settled on the bottom and underwent metamorphosis into pentactula larvae with five short tentacles at the front and two tube feet at the back. By day twenty, the tentacles and feet were more distinct and the first thorny protuberances were visible on the body. In the study, mortality of the larvae was about 95%, but this high rate was partly due to predation by copepods which the researchers were unable to eliminate from the tank. [3] Other studies have investigated how best to stimulate spawning and the optimum conditions of temperature, pH and salinity for rearing the larvae, the best diet to feed and how to stimulate them to settle. [5]
In Vietnam, a small bivalve shell, Entovalva nhatrangensis , is found living as an endosymbiont inside the oesophagus of Holothuria spinifera. The mollusc is a filter feeder and extracts nourishment from sediment that the sea cucumber has swallowed. [6]
In India, both Holothuria spinifera and the sandfish ( Holothuria scabra ) are harvested for human consumption. It is best gathered by skin diving and handled gently. Most however is caught by trawling but the resulting quality is lower than when it is brought to the surface by divers. This is because, if handled roughly it is liable to eviscerate, voiding its viscera and respiratory tree. [3] Some of the brown sandfish caught are dried and exported as beche-de-mer, particularly to China. They used to be an important article of trade but the volumes exported have diminished over the years. The sea cucumbers are easy to gather, slow to mature and need to congregate for successful reproduction and over exploitation has reduced populations. Further research has been undertaken into the hatchery technology necessary for successful rearing and it is hoped to use juveniles to seed suitable areas of the sea bed to increase the size of populations. [7]
An echinoderm is any deuterostomal animal of the phylum Echinodermata, which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While bilaterally symmetrical as larvae, as adults echinoderms are recognisable by their usually five-pointed radial symmetry, and are found on the sea bed at every ocean depth from the intertidal zone to the abyssal zone. The phylum contains about 7,600 living species, making it the second-largest group of deuterostomes after the chordates, as well as the largest marine-only phylum. The first definitive echinoderms appeared near the start of the Cambrian.
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. They are found on the sea floor worldwide. The number of known holothurian species worldwide is about 1,786, 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 trepang, namako, bêche-de-mer, or balate. Sea cucumbers serve a useful role in the marine ecosystem as they help recycle nutrients, breaking down detritus and other organic matter, after which bacteria can continue the decomposition process.
A fish hatchery is a place for artificial breeding, hatching, and rearing through the early life stages of animals—finfish and shellfish in particular. Hatcheries produce larval and juvenile fish, shellfish, and crustaceans, primarily to support the aquaculture industry where they are transferred to on-growing systems, such as fish farms, to reach harvest size. Some species that are commonly raised in hatcheries include Pacific oysters, shrimp, Indian prawns, salmon, tilapia and scallops.
Sea cucumbers are marine animals of the class Holothuroidea. They can be used as food, in fresh or dried form, in various cuisines. In some cultural contexts the sea cucumber is thought to have medicinal value.
Holothuria atra, commonly known as the black sea cucumber or lollyfish, is a species of marine invertebrate in the family Holothuriidae. It was placed in the subgenus Halodeima by Pearson in 1914, making its full scientific name Holothuria (Halodeima) atra. It is the type species of the subgenus.
Holothuria mexicana, the donkey dung sea cucumber, is commonly found in the Caribbean and the Azores. It is a commercially important aspidochirote sea cucumber that can reach a total length of 50 cm (20 in).
Australostichopus is a genus of sea cucumbers in the family Stichopodidae. It is monotypic, being represented by the single species Australostichopus mollis, commonly known as the brown sea cucumber or Australasian sea cucumber. This species has stimulated interest for its fishery potential in the Southern Hemisphere, and for its capability to reduce waste produced by aquaculture. Despite its ecological role and abundance in New Zealand coastal waters, the scarcity of knowledge regarding A. mollis biology and ecology has hindered the development of a stable fishery industry. Importantly, A. mollis represents promising business potential within an important Asian market. Recently its potential as a functional food has been evaluated, highlighting the nutritious components
Holothuria scabra, or sandfish, is a species of sea cucumber in the family Holothuriidae. It was placed in the subgenus Metriatyla by Rowe in 1969 and is the type species of the subgenus. Sandfish are harvested and processed into "beche-de-mer" and eaten in China and other Pacific coastal communities.
Sea cucumber stocks have been overexploited in the wild, resulting in incentives to grow them by aquaculture. Aquaculture means the sea cucumbers are farmed in contained areas where they can be cultured in a controlled manner. In China, sea cucumbers are cultured, along with prawns and some fish species, in integrated multi-trophic systems. In these systems, the sea cucumbers feed on the waste and feces from the other species. In this manner, what would otherwise be polluting byproducts from the culture of the other species become a valuable resource that is turned into a marketable product.
Holothuria tubulosa, the cotton-spinner or tubular sea cucumber, is a species of sea cucumber in the family Holothuriidae. It is the type species of the genus Holothuria and is placed in the subgenus Holothuria, making its full name Holothuria (Holothuria) tubulosa.
Entovalva nhatrangensis is a species of small marine bivalve mollusc in the family Lasaeidae. It was first described in 2010 and its specific name "nhatrangensis" derives from the locality where it was originally found, Nha Trang Bay in Vietnam. It lives inside the oesophagus of certain species of sea cucumbers. It is considered to be an endosymbiont rather than a parasite because it does not harm its host.
Apostichopus japonicus is a species of sea cucumber in the family Stichopodidae. It is found in shallow temperate waters along the coasts of south east Asia and is commonly known as the Japanese spiky sea cucumber or the Japanese sea cucumber.
Holothuria edulis, commonly known as the edible sea cucumber or the pink and black sea cucumber, is a species of echinoderm in the family Holothuriidae. It was placed in the subgenus Halodeima by Pearson in 1914, making its full scientific name Holothuria (Halodeima) edulis. It is found in shallow water in the tropical Indo-Pacific Ocean.
Cucumaria vegae, also known as tiny black sea cucumber or northern tar spot, is a species of sea cucumber. It was first described to science by Johan Hjalmar Théel in 1886 reporting on the sea cucumber specimens brought back by the Challenger expedition. Among these was the type specimen for this species, which was collected at Bering Island.
Holothuria grisea, the gray sea cucumber, is a mid-sized coastal species of sea cucumber found in shallow tropical waters of the Atlantic Ocean from Florida to Southern Brazil and West Africa. They have a variety in color and can range from red to more yellowish with brown markings. They are also a food source for local and international markets with the majority of harvesting taking place in Brazil. This species is currently not over-fished and is not endangered or threatened.
Holothuria arguinensis is a species of sea cucumber in the family Holothuriidae and subgenus Roweothuria. It is found in waters off the northeast Atlantic Ocean and Mediterranean Sea. According to some scholarly research, the species is actively expanding its range and colonizing the south-eastern coast of Spain.
Holothuria stellati, also known as the Brown sea cucumber,is a species of sea cucumber in the family Holothuriidae. First described by Delle Chiaje in 1824. There are two accepted subspecies, Holothuria stellatidakarensis and Holothuria stellati mammata, though there is still debate on whether or not they are separate species.
Holothuria (Roweothuria) poli, also known as the white spot cucumber, is a species of sea cucumber in the family Holothuridae and the subgenus Roweothuria. The species was first described by the Italian doctor and naturalist Stefano delle Chiaje in 1824. The species' range has been documented as being in the Mediterranean Sea, Red Sea, and the Bay of Biscay.
Holothuria (Cystipus) cubana is a species of sea cucumber in the family Holothuriidae. This species was first described by Ludwig in 1875.