Aquaculture of sea cucumbers

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Sea cucumbers are usually scavengers which feed on the debris on the sea floor Three-Rowed Sea Cucumber.jpg
Sea cucumbers are usually scavengers which feed on the debris on the sea floor

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.

Contents

History

The Chinese and Japanese were the first to develop successful hatchery technology for Apostichopus japonicus , prized for its high meat content and success in commercial hatcheries. [1] A second species, Holothuria scabra , was cultured for the first time using these techniques in India in 1988. [2] In recent years Australia, Indonesia, New Caledonia, Maldives, Solomon Islands and Vietnam have also successfully cultured H. scabra using the same technology, which has since been expanded to other species. [1]

Broodstock

Sandfish hatchery (Alaminos, Pangasinan). Sandfishjf9380.JPG
Sandfish hatchery (Alaminos, Pangasinan).
The Philippine "Balatan" or Sea cucumber breeding/harvesting. AlaminosJf381.JPG
The Philippine "Balatan" or Sea cucumber breeding/harvesting.

Sea cucumbers to be used as broodstock are either collected from the wild or are taken from commercial harvests. [2] [3] Only the largest and healthiest individuals are used for broodstock, as the success of a hatchery relies on the healthy condition of brood individuals. [2] These individuals are kept in tanks with at least 6 inches of sand to allow burrowing behaviour. Water is changed every day and sand is changed every fortnight. Sea cucumbers are fed with a paste made from freshly collected algae added to the tanks once a week to settle on sand where they feed. If water conditions are not right and if proper food is not provided sea cucumbers will eviscerate or re-absorb their gonads rendering them unfit for spawning. [2]

Spawning

Temperature shock involves cooling and heating of seawater by 3–5°C until spawning is induced. [3] This is achieved by first reducing the temperature of the water by 3–5°C. The sea cucumbers are left for five minutes before they are exposed to ‘normal’ (depending on species and climate) temperature seawater, where the small rise in water temperature is sufficient to induce spawning. [4] Males tend to spawn first which then induces females to release their eggs.

Spawning stimulation can also be achieved through lightly drying the broodstock followed by exposure to a powerful jet of seawater. [2] [4] Sea cucumbers are dried for 30 minutes in the shade and then are exposed to a powerful jet of seawater for 30 minutes. Usually 60–90 minutes later males will release their sperm, and 30 minutes after that females will swell and release eggs in rapid intermittent jets.

Though many species of sea cucumbers can be induced to spawn using both of these methods, temperature shock is usually considered to be the preferred method. Often spawn obtained from drying and wetting with a jet of water does not produce viable gametes. [4] Spawning induction and successful fertilization has only been achieved in some species of sea cucumbers and the likelihood that a method will work or not is highly dependent on the species.

Larvae

The first month after hatching is particularly crucial and mortality during the larval phases is particularly high. Larval survival drops to 30 – 34% after the first 20 days of hatching and larval development. [5] [6] Larvae usually hatch 48 hours after fertilisation and spend their first 17 days as feeding larvae or auricularia. [4] During this phase they are fed on a mix of planktonic microalgae (Rhodomonas salina, Chaetoceros calcitrans, C. mulleri, Isochrysis galbana and Pavlova lutheri are most commonly used). [3] [6] The proportions and overall quantity of microalgal feed species varies with larval stage, and the quantity is gradually increased as larvae grow until they metamorphose into the doliolaria or non-feeding phase (around day 17.) [4] Individuals in this phase of their development are put into a tank with settlement cues. These may include food items such as seagrass extract, seaweed extract, Algamac2000, Algamac Protein Plus, dead algae, benthic diatoms ( Nitzchia sp. and Navicula sp.) and spirulina. [6]

Around day 19 of development the larvae transform into their pentacula phase and settle. [4] Plates or polythene sheets are provided as substrate for larvae to settle on and to feed off. [4] Benthic diatoms Nitzchia sp. and Navicula sp. are most effective as settlement cues. [6]

Nursery

Juveniles are sometimes transferred to a sand-based feeding substrate in nursery tanks when they reach 10 mm; however, survival of juveniles is better if they are allowed to grow to 20 mm before transferral to sand. [5] Juveniles are grown for a few months until they reach 5–7 cm when they are moved out to sea ranches or into ponds. [3]

Grow out

Sea ranching is carried out in sheltered bays with seagrass in areas with few predators. The sea cucumbers can be kept in pens in shallow water made of fine wire mesh or bamboo, [2] and in deeper water they are raised in cages made from fine woven mesh or in tub enclosures on the seafloor. They can also be kept and grown in ponds with appropriate water exchange and movement. [3] Individual growth is density-dependent and is stunted at high densities. [5] Monitoring water quality and growth characteristics are essential to survival during this phase. [5] Sea cucumbers are ready to harvest after 12 months of grow out. [2]

Asexual methods

Thelenota ananas.jpg
Stichopus chloronotus.jpg
The prickly redfish (left) and greenfish (right)
can be asexually propagated

Two sea cucumber species Thelenota ananas (prickly redfish) and Stichopus chloronotus (greenfish) have been found capable of asexual propagation through transverse fission, [7] the process whereby an organism is cut in half and completely regenerates the missing half. Rubber bands are placed around the middle of the sea cucumbers which induces them to undergo fission within 1–2 weeks. After separating, the posterior half regrows a complete anterior half, and vice versa. This happens within 3–7 months, producing two new fully-grown individuals from one. Survival from this process by these species was found to be 80% or greater. [7] Though this technique is not suitable for all sea cucumber species, it may provide a cheaper and faster alternative method of obtaining prickly redfish and greenfish for aquaculture.[ citation needed ]

Polyculture

Sea cucumbers are currently cultured in polyculture with prawns and some fish species. Their presence in the bottoms of the pens or nets, where they feed on debris composed of feces, excess food, algae, and other particulate organic matter, significantly reduces fouling of water and equipment. [8] China currently produces around 90,000 tons of sea cucumbers using these practices [9] and enhanced growth of sea cucumber juveniles has been reported when they are grown at the bottom of prawn farms. [1] Farming sea cucumbers with the fouling debris of other aquaculture species helps to mitigate the impacts of marine farms' effluents and turns these wastes into a marketable product. [8] [9]

Notes

  1. 1 2 3 James, B. D. (2004). Captive breeding of the sea cucumber, Holothuria scabra, from India. In Lovatelli, A. (comp./ed.); Conand, C.; Purcell, S.; Uthicke, S.; Hamel, J.-F.; Mercier, A. (eds.) Advances in sea cucumber aquaculture and management. FAO Fisheries Technical Paper. No. 463. Rome, FAO. 2004. 425p.
  2. 1 2 3 4 5 6 7 James, D. B., Gandhi, A. D., Palaniswamy, N., & Rodrigo, J. X. (1994). Techniques and Culture of the Sea-cucumber Holothuria scabra. CMFRI Special Publication(57), 1–40.
  3. 1 2 3 4 5 Giraspy, D. A. B., & Walsalam, I. G. (2010). Aquaculture potential of the tropical sea cucumbers Holothuria scabra and H. lessoni in the Indo-Pacific region SPC Beche-de-mer Information Bulletin(30), 29–32.
  4. 1 2 3 4 5 6 7 Laxminarayana, A. (2005). Induced spawning and larval rearing of the sea cucumbers, Bohadschia marmorata and Holothuria atrain Mauritius. SPC Beche-de-mer Information Bulletin (22), 48–52..
  5. 1 2 3 4 Battaglene, S. C., Seymour, J. E., & Ramofafia, C. (1999). Survival and growth of cultured juvenile sea cucumbers, Holothuria scabra. Aquaculture, 178(3–4), 293–322.
  6. 1 2 3 4 Ivy, G. and D. A. B. Giraspy (2006). Development of large-scale hatchery production techniques for the commercially important sea cucumber Holothuria scabra var. versicolor (Conand, 1986) in Queensland, Australia Archived October 6, 2009, at the Wayback Machine . SPC Beche-de-mer Information Bulletin(24).
  7. 1 2 Reichenbach, N., & Holloway, S. (1995). Potential for Asexual Propagation of Several Commercially Important Species of Tropical Sea Cucumber (Echinodermata). Journal of the World Aquaculture Society, 26(3), 272–278.
  8. 1 2 Ahlgren, M. O. (1998). Consumption and Assimilation of Salmon Net Pen Fouling Debris by the Red Sea Cucumber Parastichopus californicus: Implications for Polyculture. Journal of the World Aquaculture Society 29(2): 133–139.
  9. 1 2 Connor, S. (2011). "Ready to acquire a taste for the 'vacuum cleaners of the sea'?". Retrieved 28/09/2011, from https://www.independent.co.uk/news/science/ready-to-acquire-a-taste-for-the-vacuum-cleaners-of-the-sea-2202601.html.

Further references

Related Research Articles

Sea cucumber Class of echinoderms

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 holothurian 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 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 degradation process.

Indian prawn Species of crustacean

The Indian prawn, is one of the major commercial prawn species of the world. It is found in the Indo-West Pacific from eastern and south-eastern Africa, through India, Malaysia and Indonesia to southern China and northern Australia. Adult shrimp grow to a length of about 22 cm (9 in) and live on the seabed to depths of about 90 m (300 ft). The early developmental stages take place in the sea before the larvae move into estuaries. They return to the sea as sub-adults.

Broodstock, or broodfish, are a group of mature individuals used in aquaculture for breeding purposes. Broodstock can be a population of animals maintained in captivity as a source of replacement for, or enhancement of, seed and fry numbers. These are generally kept in ponds or tanks in which environmental conditions such as photoperiod, temperature and pH are controlled. Such populations often undergo conditioning to ensure maximum fry output. Broodstock can also be sourced from wild populations where they are harvested and held in maturation tanks before their seed is collected for grow-out to market size or the juveniles returned to the sea to supplement natural populations. This method, however, is subject to environmental conditions and can be unreliable seasonally, or annually. Broodstock management can improve seed quality and number through enhanced gonadal development and fecundity.

Fish hatchery Aquaculture facility

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. The value of global aquaculture production is estimated to be US$98.4 billion in 2008 with China significantly dominating the market; however, the value of aquaculture hatchery and nursery production has yet to be estimated. Additional hatchery production for small-scale domestic uses, which is particularly prevalent in South-East Asia or for conservation programmes, has also yet to be quantified.

Pacific oyster Species of bivalve

The Pacific oyster, Japanese oyster, or Miyagi oyster, is an oyster native to the Pacific coast of Asia. It has become an introduced species in North America, Australia, Europe, and New Zealand.

Oyster farming Commercial growing of oysters

Oyster farming is an aquaculture practice in which oysters are bred and raised mainly for their pearls, shells and inner organ tissue, which is eaten. Oyster farming was practiced by the ancient Romans as early as the 1st century BC on the Italian peninsula and later in Britain for export to Rome. The French oyster industry has relied on aquacultured oysters since the late 18th century.

Sea cucumber as food Used in fresh or dried form in various cuisines.

Sea cucumbers are marine animals of the class Holothuroidea. They are used as food, in fresh or dried form, in various cuisines. In some cultural contexts the sea cucumber is thought to have medicinal value.

<i>Isostichopus fuscus</i> Species of sea cucumber

Isostichopus fuscus, commonly known as the brown sea cucumber, is a species of sea cucumber in the family Stichopodidae native to the eastern Pacific. It was first described to science by German biologist Hubert Ludwig in 1875.

<i>Holothuria atra</i> Species of sea cucumber

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.

<i>Holothuria mexicana</i> Species of sea cucumber

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).

<i>Tectus niloticus</i> Species of gastropod

Tectus niloticus, common name the commercial top shell, is a species of sea snail, a marine gastropod mollusk in the family Tegulidae.

<i>Australostichopus</i> Genus of sea cucumbers

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

Scallop aquaculture Commercial activity of cultivating (farming) scallops

Scallop aquaculture is the commercial activity of cultivating (farming) scallops until they reach a marketable size and can be sold as a consumer product. Wild juvenile scallops, or spat, were collected for growing in Japan as early as 1934. The first attempts to fully cultivate scallops in farm environments were not recorded until the 1950s and 1960s. Traditionally, fishing for wild scallops has been the preferred practice, since farming can be expensive. However worldwide declines in wild scallop populations have resulted in the growth of aquaculture. Globally the scallop aquaculture industry is now well established, with a reported annual production totalling over 1,200,000 metric tonnes from about 12 species. China and Japan account for about 90% of the reported production.

<i>Holothuria scabra</i> Species of sea cucumber

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.

Aquaculture of cobia

Cobia, a warm water fish, is one of the more suitable candidates for offshore aquaculture. Cobia are large pelagic fish, up to 2 metres (6.6 ft) long and 68 kilograms (150 lb) in weight. They are solitary fish except when spawning, found in warm-temperate to tropical waters.

<i>Holothuria tubulosa</i> Species of sea cucumber

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.

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. 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. It is fished commercially to produce beche-de-mer.

Geoduck aquaculture Farming and cultivation of geoduck

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<i>Holothuria edulis</i> Species of 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.

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.

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