Isostichopus fuscus

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Isostichopus fuscus
Stichopus sp.png
Isostichopus cuscus, brown sea cucumber underside.jpg
Isostichopus fuscus underside
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Echinodermata
Class: Holothuroidea
Order: Synallactida
Family: Stichopodidae
Genus: Isostichopus
Species:
I. fuscus
Binomial name
Isostichopus fuscus
(Ludwig, 1875)

Isostichopus fuscus, commonly known as the brown sea cucumber, is a species of sea cucumber in the family Stichopodidae [1] native to the eastern Pacific. [2] It was first described to science by German biologist Hubert Ludwig in 1875. [3]

Contents

It has a thick dermis without any spikes, making it an easily edible species and thus it is harvested for export to East Asia, where sea cucumber is popular in some cuisines. [2] [4] The fishery is typically conducted in an unsustainable manner, mostly in North and South America, which has caused the populations to decline. [2] The brown sea cucumber is classified by the IUCN as Endangered. [2]

Distribution and habitat

This species is found in the Pacific Coast of Mexico, including the Gulf of California, and down through Central America to South America as far as the northern coast of Peru, as well as in eastern Pacific islands, including the Galápagos. [1] [2] They are found in shallow waters, roughly 0 to 40 m deep in rocky reefs, although 3 to 29 m are a preferred range. Additionally, reefs with sandy patches seem to be a preferred substrate. [5] Within these depths, I. fuscus has been found to predominate areas where high amounts of Ulva sp. are located. [5] The species tends to be more active at night as during the daytime they are cryptic and being active would make them more visible to predators. [6] [7]

Feeding

Like other sea cucumber, I. fuscus is a deposit feeder, whose survival tends to increase with soft-substrates such as sand or clay. Recent studies suggest that a blend of seaweed species such as P. durvillaei and S. ecuadoreanum are an optimal diet, although they can survive off of other types of seaweed. [8]

Morphology

The brown sea cucumber are quite small organisms, with average body length and weight being 23 cm and 386 g, respectively. [9] The largest samples have been recorded reaching up to 40 cm and weighing 830 g, although weight varies seasonally according to reproduction and the maturity stage. [10] The species grows allometrically, meaning that increases with body length are also associated with increases in weight. [9] Isostichopus fuscus is dioecious. Gonads can only be determined and sexed under a microscope. There is no apparent sexual dimorphism among individuals, unless gonads are ripe. [11] When gonads are ripe, males are a white color, while females gonads are orange. [11] The brown sea cucumber has an elongated body and can be described as having a soft or gelatinous texture. [4] Their general body shape is curved, similar to a half circle, and they have a dark brown coloration and are spotted with orange papillae. [4] They have ambulacral extensions on their underside which are used to help with locomotion. [4]  

Typically, the brown sea cucumber is a brown color, as evident by its name. However, in 2013, the first ever record of albinism was discovered in the brown sea cucumber. [12] Two albino individuals were found: one in Loreto, Mexico and the other in the Los Angeles Bay. [12]

Reproductive cycle

Sexual reproduction

Spawning occurs in Isostichopus fuscus from July to September, with post-spawning gonads occurring in October. [11] Gametogenesis was documented between January and July, with oogenesis occurring approximately one month before spermatogenesis. [11] Peaks in reproduction followed by drastic declines have characterized I. fuscus as an episodic spawner, in which water temperature is thought to play a large role as a reproductive indicator. [13]

The reproductive cycle of the brown sea cucumber consists of five gonadal stages: under-determined, gametogenesis, maturity, spawning and post-spawning. The species moves through these 5 stages on an annual cycle. In the undetermined stage, gametes or gonads observed in the individuals, and therefore they are sexually viable. Any gonads that can be observed cannot be accurately distinguished at this stage. [11] Connective tissue in the lumen is present and the gonadal wall is thickened [14] The following four stages are different among males and females. [15]

In males, the gametogenesis stage is called spermatogenesis, and refers to when there is a build up of sperm in the gonads. During spermatogenesis, folds in the gonadal wall are present that the lumen. [14] Additionally, Spherical spermatocytes accumulate at the periphery. [11] The accumulation of spermatocytes causes a decrease in the thickness of the connective tissue. [14] During the maturity, the follicles of the gonads are filled with multiple layers of mature sperm. The mature spermatozoa exhibit a rounded shape are slightly dorso-ventrally flattened. [14] A thin layer of spermatocytes is present at the periphery. [11]   Spawning is when the individuals have mated, and therefore the follicles in the gonads are empty due to the sperm being released. Developing spermatocytes are still present at the periphery layer. a layer of connective tissue is present at the gonad wall [11] The gonadal wall is observed to thicken, and folds are present inside of the wall. [16] Spawning in brown sea cucumbers occurs throughout the summer months. Finally, in post spawning, large quantity of phagocytes is present both inside and outside of the follicles. [14] Connective tissue is reabsorbed in the gonadal wall of the follicle, [11] the gonads are engulfed by phagocytes, therefore ending a single reproductive cycle in males. [15]

In females, the gametogenesis stage is called oogenesis, and is when the oocytes are young and in the process of developing. Oogonia are attached to the germinal epithelium in the lumen. [14] The oocytes are arranged in a single layer, and have a defined nucleus and peripheral nucleoli. [14] [11] The connective tissue and folds in the gonad gradually reduce as oogenesis progresses. [14] In the maturity stage, the oocytes are mature and have reached their maximum size. Oocytes are present in all tubules in the lumen, and their peripheral nuclei are distinguishable. [11] [14] Connective tissue is absent, and the gonadal wall is very thin (3). Phagocytes surround the inside and outside of the lumen. [14] [11] During the spawning stage, there is a decrease in the number of oocytes and an absence of gametes due to spawning. A layer of connective tissue is present at the gonad wall [11] The gonadal wall is observed to thicken, and folds are present inside of the wall. [14] Any of the remaining oocytes are either in maturity or oogenesis [14] Lastly, in post spawning, oocytes observed have significantly decreased in volume. [11] Large amounts of connective tissue are present in the gonadal walls. [11] Phagocytes are involved in reducing the number of gonads present, thus ending the reproductive cycle in females. [15]

Hermaphroditic reproduction

Although rare, hermaphroditic samples have been collected. In these cases, the male and female follicles were in different gonadal stages, and some samples were in the spawning stages. In one case, both male and female follicles were in the spawning stages. [14]

Asexual reproduction

The potential for asexual reproduction is possible. Like most echinoderms, I. fuscus has a unique regenerative ability. Induced transverse fission has been experimented in a lab setting. The results were successful, showing a high survival rate, and a complete regeneration of anterior and posterior body parts in a maximum of three months. The results suggest that asexual propagation could serve as a potential tool for restoring their population in the wild. [17]

Development

The development of I. fuscus is separated into larval and juvenile phases. The larval phase begins after the organism hatches from its embryonic envelope, and undergo a series of transformations for approximately 22 days; The juvenile stage is initiated afterwards. [18]

Larval development

Embryos hatch from the fertilization envelope roughly 10 hours after fertilization. The gastrulae have an epidermal layer that is entirely ciliated and supports their movement. After approximately 24 hours, the gastrulae transform into an auricularia larvae. Feeding begins upon the transition to this stage. After 19–24 days, the doliolaria stage is reached, where the larvae shrink to 50 percent of their size. 5 days later, the pentactula stage is reached, in which the organism goes through a settlement phase. [18]

Juvenile development

Early settled juveniles are typically 1-1.5 mm in length. Over a 3-4 week period, they undergo rapid growth at an average rate of 0.5–1 mm/day. The juveniles begin to develop brown pigment when they reach a length of approximately 5 mm, and tentacles are visible at about 8mm. At approximately day 52, papillae and an elongated intestine, which suggest peristaltic movements become present. The tegument thickness increase, and the epidermis transforms from a transparent to opaque appearance. At 2 cm in length, the coloration fades to a brown that is characteristic of an adult brown sea cucumber. [18]

Fisheries and uses

The brown sea cucumber is a highly sought out commodity in many North and South American countries, including Mexico, Costa Rica and Ecuador. Sea cucumber fishing is also seen as the most important fishing activity in the Galápagos Islands. As it is such a common item in the fisheries of these countries, overfishing and overexploitation of the brown sea cucumber is a vast problem. Due to the endangered state of the brown sea cucumber, the Galápagos Marine Reserve and all major stakeholders took it upon themselves to monitor its population in the Galápagos twice a year between 1999 and 2003 in order to determine the impact of the fisheries and any possible solutions for it. [19] The lowest total density of the population was seen following the 2003 fishing season, and due to this ultimate low, the recovery of the brown sea cucumber population is seen as unlikely due to both the legal and illegal fishing of them. [19]

Sea cucumbers are typically used in traditional Chinese medicines as well as in many Asian and South American cuisines. Like most other holothurians, the brown sea cucumber is a very nutritional food source. It is high in protein, low in fat and contains many amino acids necessary for keeping us healthy. [20] It is often combined with other ingredients in soups and stews and more recently, dried sea cucumber is made into tablets and has been marketed as a nutritional supplement. [20]

Due to the unsustainable fisheries pertaining to this species as well as its high demand in many Asian and South American cuisines, it has ultimately caused a decline in not just Isostichopus fuscus, but many holothurian populations. [6]

Related Research Articles

<span class="mw-page-title-main">Sea cucumber</span> 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. 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.

<span class="mw-page-title-main">Germ cell</span> Gamete-producing cell

A germ cell is any cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate in the primitive streak and migrate via the gut of an embryo to the developing gonads. There, they undergo meiosis, followed by cellular differentiation into mature gametes, either eggs or sperm. Unlike animals, plants do not have germ cells designated in early development. Instead, germ cells can arise from somatic cells in the adult, such as the floral meristem of flowering plants.

<span class="mw-page-title-main">Ovarian follicle</span> Structure containing a single egg cell

An ovarian follicle is a roughly spheroid cellular aggregation set found in the ovaries. It secretes hormones that influence stages of the menstrual cycle. At the time of puberty, women have approximately 200,000 to 300,000 follicles, each with the potential to release an egg cell (ovum) at ovulation for fertilization. These eggs are developed once every menstrual cycle with around 450–500 being ovulated during a woman's reproductive lifetime.

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

Isostichopus badionotus, also known as the chocolate chip cucumber or the cookie dough sea cucumber, is a species of sea cucumber in the family Stichopodidae. This common species is found in warm parts of the Atlantic Ocean.

Evisceration is a method of autotomy involving the ejection of internal organs used by animals as a defensive strategy. Sea cucumbers (Holothuroidea) eject parts of the gut in order to scare and defend against potential predators such as crabs and fish. The organs are regenerated in a few days by cells in the interior of the sea cucumber.

<i>Scotoplanes</i> Genus of deep-sea sea cucumbers known as sea pigs

Scotoplanes is a genus of deep-sea sea cucumbers of the family Elpidiidae. Its species are commonly known as sea pigs.

<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>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

<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.

<i>Colochirus robustus</i> Species of echinoderm

Colochirus robustus, commonly known as the robust sea cucumber or the yellow sea cucumber, is a species of sea cucumber in the family Cucumariidae. It is found in shallow seas in tropical parts of the central Indo-Pacific region. C. robustus belongs to the class Holothuroidea, a group of echinoderms called sea cucumbers and known for unusual behavior including evisceration, asexual reproduction, and regeneration. The robust sea cucumber has a soft body and lacks a spine, but it does have an endoskeleton consisting of microscopic spicules, or ossicles, made of calcium carbonate. C. robustus has a respiratory tree that allows it to extract oxygen for respiration, using the anus to pump water. The robust sea cucumber is an important dietary staple for many East and Southeast Asian populations, and has been used for medicinal purposes for hundreds of years. Recent research suggests that peptides from C. robustus enhance the activity of the immune system.

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

Holothuria floridana, the Florida sea cucumber, is a species of marine invertebrate in the family Holothuriidae. It is found on the seabed just below the low tide mark in Florida, the Gulf of Mexico, the Bahamas and the Caribbean.

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

Holothuria parvula, the golden sea cucumber, is a species of echinoderm in the class Holothuroidea. It was first described by Emil Selenka in 1867 and has since been placed in the subgenus Platyperona, making its full scientific name Holothuria (Platyperona) parvula. It is found in shallow areas of the Caribbean Sea and Gulf of Mexico and is unusual among sea cucumbers in that it can reproduce by breaking in half.

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

Stichopus is a genus of sea cucumbers from the family Stichopodidae.

<i>Pelagothuria</i> Species of sea cucumber

Pelagothuria is a genus of sea cucumbers in the family Pelagothuriidae. It is monotypic, being represented by the single species Pelagothuria natatrix.

<span class="mw-page-title-main">Chiridotidae</span> Family of sea cucumbers

Chiridotidae is a family of sea cucumbers found in the order Apodida. Within the family, there are 16 recognized genera all with different ranges of body types and functions. Sea cucumbers play a fundamental role in many marine ecosystems.

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.

<span class="mw-page-title-main">Psychropotidae</span> Family of sea cucumbers

Psychropotidae is a family of deep-sea swimming sea cucumbers. The geographic range of some psychropotids is very extensive at abyssal depths, whereas other species are found within more restricted ranges.

<i>Actinopyga varians</i> Species of sea cucumber

Actinopyga varians, the Pacific white-spotted sea cucumber or Hawaiian sea cucumber, is a species of sea cucumber in the family Holothuriidae. It is found in the Pacific Ocean near Hawaii and also in the Indo-Pacific Ocean.

Holothuria (Cystipus) cubana is a species of sea cucumber in the family Holothuriidae. This species was first described by Ludwig in 1875.

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

Holothuria (Microthele) whitmaei, commonly known as the black teatfish, is a species of sea cucumber in the family Holothuriidae. The sea cucumber is distributed in the western Indian and Pacific oceans, with specimens being found off of Tanzania, New Caledonia and the Philippines. They are usually found in groups of 5-25 individuals.

References

  1. 1 2 3 Mercier, A.; Hamel, J.-F.; Toral-Granda, T.-G.; Alvarado, J.J.; Paola Ortiz, E.; Benavides, M. (2013). "Isostichopus fuscus". IUCN Red List of Threatened Species . 2013: e.T180373A1621878. doi: 10.2305/IUCN.UK.2013-1.RLTS.T180373A1621878.en . Retrieved 12 November 2021.
  2. 1 2 3 4 5 "The IUCN Red List of Threatened Species". IUCN Red List of Threatened Species. Retrieved 2018-12-27.
  3. ↑ Ludwig, Hubert (1875). "Beitrage zur Kenntniss der Holothurien". Arbeiten aus dem Zoologisch-Zootomischen Institut in Wurzburg (in German): 97–98.
  4. 1 2 3 4 Gutiérrez-García, Alexandra (1999). "Potential culture of sea cucumber in Mexico" (PDF). SPC Beche-de-Mer Information Bulletin. 11: 26–29.
  5. 1 2 Toral-Granda, M. Verónica; Martínez, Priscilla C. (2007-07-01). "Reproductive biology and population structure of the sea cucumber Isostichopus fuscus (Ludwig, 1875) (Holothuroidea) in Caamaño, Galápagos Islands, Ecuador". Marine Biology. 151 (6): 2091–2098. doi:10.1007/s00227-007-0640-1. ISSN   1432-1793. S2CID   84736133.
  6. 1 2 Toral-Granda, M. Verónica; Martínez, Priscilla C. (2007-02-24). "Reproductive biology and population structure of the sea cucumber Isostichopus fuscus (Ludwig, 1875) (Holothuroidea) in Caamaño, Galápagos Islands, Ecuador". Marine Biology. 151 (6): 2091–2098. doi:10.1007/s00227-007-0640-1. ISSN   0025-3162. S2CID   84736133.
  7. ↑ Shepherd, SA; Toral-Granda, MV; Edgar, GV (2003). "Estimating the abundance of clustered and cryptic marine macro-invertebrates in the Galápagos with particular reference to sea cucumbers" (PDF). Noticias de Galápagos. 62: 36–39.
  8. ↑ Sonnenholzner, Jorge I.; Searcy-Bernal, Ricardo; Panchana-Orrala, María (January 2017). "The potential for propagation of the commercial sea cucumber Isostichopus fuscus (Ludwig, 1875) by induced transverse fission". Regional Studies in Marine Science. 9: 35–42. doi:10.1016/j.rsma.2016.10.006. ISSN   2352-4855.
  9. 1 2 Herrero-Pérezrul, María Dinorah; Reyes-Bonilla, Héctor (2008). "Weight-Length relationship and relative condition of the holothurian Isostichopus fuscus at Espíritu Santo Island, Gulf of California, México". Revista de Biología Tropical. 56 (3): 273–280.
  10. ↑ Herrero-Perezrul, M.D.; Reyes-Bonilla, H (2008). "Weight-Length relationship and relative condition of the holothurian Isostichopus fuscus at Espiritu Santo Isalnd, Fulg of California, Mexico". Revista de Biologia. 56 (3): 273–280.
  11. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Herrero-Pérezrul, M. D.; Reyes Bonilla, H.; García-Domínguez, F.; Cintra-Buenrostro, C. E. (1999-12-01). "Reproduction and growth of Isostichopus fuscus (Echinodermata: Holothuroidea) in the southern Gulf of California, México". Marine Biology. 135 (3): 521–532. doi:10.1007/s002270050653. ISSN   1432-1793. S2CID   59335774.
  12. 1 2 Fernández-Rivera Melo, F.J.; Reyes-Bonilla, H.; Cantú, A.; Urías, J. (2015). "First record of albinism in the brown sea cucumber Isostichopus fuscus in the Gulf of California, Mexico". Marine Biodiversity Records. 8. doi:10.1017/s1755267214001353. ISSN   1755-2672.
  13. ↑ Toral-Granda, M. Verónica; Martínez, Priscilla C. (2007-07-01). "Reproductive biology and population structure of the sea cucumber Isostichopus fuscus (Ludwig, 1875) (Holothuroidea) in Caamaño, Galápagos Islands, Ecuador". Marine Biology. 151 (6): 2091–2098. doi:10.1007/s00227-007-0640-1. ISSN   1432-1793. S2CID   84736133.
  14. 1 2 3 4 5 6 7 8 9 10 11 12 13 Pañola-Madrigal, Abigail; Calderon-Aguilera, Luis E.; Aguilar-Cruz, Carlos A.; Reyes-Bonilla, Héctor; Herrero-Pérezrul, María Dinorah (2017-12-08). "Reproductive cycle of the sea cucumber (Isostichopus fuscus) and its relationship with oceanographic variables at its northernmost distribution site". Revista de Biología Tropical. 65 (1): 180. doi: 10.15517/rbt.v65i1-1.31687 . ISSN   2215-2075.
  15. 1 2 3 Herrero-Pérezrul, M. D.; Reyes Bonilla, H.; García-Domínguez, F.; Cintra-Buenrostro, C. E. (1999-12-04). "Reproduction and growth of Isostichopus fuscus (Echinodermata: Holothuroidea) in the southern Gulf of California, México". Marine Biology. 135 (3): 521–532. doi:10.1007/s002270050653. ISSN   0025-3162. S2CID   59335774.
  16. ↑ Toral-Granda, M. Verónica; Martínez, Priscilla C. (2007-07-01). "Reproductive biology and population structure of the sea cucumber Isostichopus fuscus (Ludwig, 1875) (Holothuroidea) in Caamaño, Galápagos Islands, Ecuador". Marine Biology. 151 (6): 2091–2098. doi:10.1007/s00227-007-0640-1. ISSN   1432-1793. S2CID   84736133.
  17. ↑ Sonnenholzner, Jorge I.; Searcy-Bernal, Ricardo; Panchana-Orrala, María (January 2017). "The potential for propagation of the commercial sea cucumber Isostichopus fuscus (Ludwig, 1875) by induced transverse fission". Regional Studies in Marine Science. 9: 35–42. doi:10.1016/j.rsma.2016.10.006. ISSN   2352-4855.
  18. 1 2 3 Hamel, Jean-Francois; Ycaza Hidalgo, Roberto; Mercier, Annie (2003). "Larval development and juvenile growth of the Galapagos sea cucumber Isostichopus fuscus". Society for the Exploration and Valuing of the Environment: 1–8 – via researchgate.
  19. 1 2 Toral-Granda, M. Verónica; Martínez, Priscilla C. (2005). "Population density and fishery impacts on the sea cucumber (Isostichopus fuscus) in the Galápagos Marine Reserve". FAO Fisheries Technical Paper: 91–100.
  20. 1 2 Chen, J (2003). "Overview of sea cucumber farming and sea ranching practices in China" (PDF). SPC Beche-de-mer Information Bulletin. 18: 18–23.
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