Australostichopus mollis Southern sea cucumber P2143491

''Australostichopus'' is a genus of sea cucumbers in the family

Stichopodidae The Stichopodidae are a family of sea cucumbers, part of the order Synallactida. Description Members of this family are mostly large or medium-sized holothuroids with a squarish cross-section, a flat ventral surface, and large, fleshy, cone-s ...

. It is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

, being represented by the single species ''Australostichopus mollis'',Moraes,G., Norhcote, P.C., Kalinin,V.I. ,Avilov, S.A., Silchenko,A.S., Dmitrenok, P.S. 2004. Structure of the major triterpene glycoside from the sea cucumber ''Stichopus mollis'' and evidence to reclassify this species into the new genus ''Australostichopus''. Biochemical Systematics and Ecology. 32 (7): 637–650. commonly known as the brown sea cucumber or Australasian sea cucumber. This species has stimulated interest for its fishery potential in the Southern Hemisphere,Stenton-Dozey, J. and Heath, P. 2009. A first for New Zealand: culturing our endemic sea cucumber for overseas markets. Water & Atmosphere .17(1). and for its capability to reduce waste produced by

aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...

. 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 Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...

industry. Importantly, ''A. mollis'' represents promising business potential within an important Asian market.Morgan, A. & Archer, J. 1999. Overview: Aspects of sea cucumber industry research and development in the South Pacific. SPC Beche-de mer Information Bulletin. 12. Recently its potential as a functional food has been evaluated, highlighting the nutritious components

Distribution

In New Zealand, ''A. mollis'' is found around the entire coast line of the country, sometimes co-existing with reef structures;Slater, M.J. & Jeffs, A.G. 2010. Do benthic sediment characteristics explain the distribution of juveniles of the deposit-feeding sea cucumber ''Australostichopus mollis''?. J. Sea Res. . and from

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

to south

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

. The species principally inhabits the

littoral The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...

low tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables can ...

level on sand, as well as in mud in protected areas. Their vertical range goes from shallows waters on the coast to around 200 metres of depth.Dawbin, W. H. 1950. A Guide to the Holothurians of New Zealand. Tuatara: Journal of the Biological Society. Vol. 3. Issue 1.Dawbin, W.H. (1948a). Auto-evisceration and regeneration of the viscera in the holothurian Stichopus mollis (Hutton). Transactions of the Royal Society of New Zealand. 77(4): 497–523

Anatomy

Adult size is typically from 13 to 25 cm.Sewell, M.A. 1990. Aspects of the ecology of Stichopus mollis (Echinodermata: Holothuroidea) in north-eastern New Zealand. NZ J. Mar. Freshw. Res. 24: 97–103. Body is soft, and colour varies from light mottled brown to black. A

tube foot Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on britt ...

is present ventrally or extending up the whole body. Tentacles (20) with disc shaped tips surround the slit-like mouth. Retractor muscles are absent. Dorsally, ''A. mollis'' has pointed

papillae Papilla (Latin, 'nipple') or papillae may refer to: In animals * Papilla (fish anatomy), in the mouth of fish * Basilar papilla, a sensory organ of lizards, amphibians and fish * Dental papilla, in a developing tooth * Dermal papillae, part of ...

which can be reduced on preservation.

Feeding

Described as detritivores, ''A. mollis'' mainly capture particles of

organic matter Organic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have c ...

from the substrata, which is highly nutritious.Slater, M.J. & Carton, A. G. 2009. Effect of sea cucumber (''Australostichopus mollis'') grazing on coastal sediments impacted by mussel farm deposition. Marine Pollution Bulletin. 58: 1123–1129.

Reproduction

Via

sexual reproduction Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote tha ...

, and sexes are generally separate, however some hermaphrodites have been found. Population

sex ratio The sex ratio (or gender ratio) is usually defined as the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is typically about 1:1 in species which reproduce sexually. Many species devia ...

is 1:1.

Reproductive season Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and cha ...

is from October to February,Sewell, M. A. and P. R. Berquist. 1990. Variability in the reproductive cycle of Stichopus mollis (Echinodermata:Holothuroidea). Invertebrate Reproduction and Development. 17(1):1–7. and periodicity of spawning is regulated by lunar cycles, specifically following a full moon.Morgan, A. 2009. Spawning of the Temperate sea cucumber, ''Australostichopus mollis''(Levin). Journal of the World Aquaculture Society. Vol. 40. No. 3. Morphologic changes in reproductive periods include females changes in

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...

colour and

oocyte An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ...

numbers, while in males there is an increase in the amount of

spermatozoa A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, ...

in particular zones described as "wet mounts of 'mashed' gonad tissue". Furthermore, there is an increase in

in the lumen of histological sections. Studies suggest that spawning may occur repeatedly during a single

reproductive season Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and cha ...

Auto-evisceration

Like other

holothurians 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 ...

, ''A. mollis'' has the ability to regenerate its internal organs after undergoing a phenomenon called auto-

evisceration Evisceration (pronunciation: /ɪvɪsəˈreɪʃən/) is disembowelment, i.e., the removal of viscera (internal organs, especially those in the abdominal cavity). The term may also refer to: * Evisceration (autotomy), ejection of viscera as a defen ...

. This process, which is thought to be induced by external stimuli, is characterized by violent and rapid expulsion of organs, followed by regeneration, which occurs at a slower rate than in other

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

. Nevertheless, a more recent study reports no spontaneous evisceration or seasonal atrophy of the viscera, highlighting that handling these organisms does not trigger such reactions and even suggesting than during

predation Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

it would not occur easily.

Predation

Available information posits the existence of just one predator: the

starfish Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish ...

'' Luidia varia'', observed in two cases. To date there is no evidence to suggest any fish or other organism preying on ''A. mollis''.

Juveniles

Juveniles are distributed in the shallow sub-tidal zone (5–8 m of depth), relatively close to where adults are concentrated. However, they are usually found in a different substrata; one of smaller grain size, and associated to macroalgae as initial settlement, where they obtain detritus and protection from predators. These factors are thought to drive distribution, rather than and food type and availability. Experimental data shows high survival rates of juveniles using a natural diet, and still higher rates in a mussel waste medium. Thanks to attempts to produce juveniles in a commercial scale a better understanding of early post-settlement juveniles' growth and pigmentation process has been achieved

Fishery

Processed sea cucumbers are traded under the name of ''beche-de-mer'', representing an important fishery in South Pacific and

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

n nations. In

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, where its exploitation occurs on a small-scale, this species is under the New Zealand fisheries quota management system and is principally caught by free-diving. Sea cucumber yields can be very profitable if the resource is adequately processed, or if a value-added policy is implemented. Currently, due to the expansion of commercial exploitation of ''A. mollis'' in New Zealand and Australia, first attempts at massive culture are being carried out. A new approach to sea cucumber farming has been the so-called

polyculture In agriculture, polyculture is the practice of growing more than one crop species in the same space, at the same time. In doing this, polyculture attempts to mimic the diversity of natural ecosystems. Polyculture is the opposite of monoculture, i ...

, where sea cucumber are bred together with mussels and

finfish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of liv ...

, consuming the wastes from nearby farming as a food supply, and at the same time providing new products. Trials farming sea cucumber with

abalone Abalone ( or ; via Spanish , from Rumsen ''aulón'') is a common name for any of a group of small to very large marine gastropod molluscs in the family (biology), family Haliotidae. Other common name In biology, a common name of a taxon o ...

have shown not to be biologically viable.

Larvae development

The complete

larvae 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 ...

stage takes approximately 21 days. After

fertilization Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...

there are seven stages of larva metamorphosis: cleavage, blastocyst, gastrulation, auricularia (subdivided in early, mid, late), doliolaria (mid metamorphic stage pre settlement), penttactula and the last settled sea cucumber larva, visible to the naked human eye, which develops into the final organism.Morgan, A. 2009. Spawning of the Temperate Sea Cucumber, Australostichopus mollis (Levin). Journal of the World Aquaculture Society. Vol. 40. No. 3

Polycultures

Considering the detritus-feeding characteristic of

, and their role on coastal marine systems, several studies have focussed on their

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...

effect on

sediments Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand a ...

. These studies have calculated declines in total organic carbon and

chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to a ...

a and phaeopigment accumulation, positioning ''A. mollis'' as an effective tool to avoid, restore and control pollutive impacts of coastal

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

. In terms of evaluating the feasibility of polycultures, this has been evaluated in the field under Greenshell mussel and Pacific oysters' farms.Zamora, L.N., Dollimore, J. and Jeffs, A.G., 2014. Feasibility of co-culture of the Australasian sea cucumber (''Australostichopus mollis'') with the Pacific oyster (''Crassostrea gigas'') in northern New Zealand. New Zealand Journal of Marine and Freshwater Research, 48(3), pp.394–404. In land based systems, according to the energetic requirements of adult sea cucumbers, results have inferred that waste production of an industry standard-type abalone lacks sufficient energy to meet ''A. mollis'' metabolic needs. However, there is suggestion that feeding juveniles from these wastes could be feasible.Maxwell, K., Gardner, J.P.A., Heath, P., 2009. The effect of diet on the energy budget of the brown sea cucumber, ''Stichopus mollis'' (Hutton). J. World Aquac. Soc. 40: 159–170. Conversely, waste generation from fresh mussels have proven to be the source of enough energy to sustain juvenile stocks, assuming a suitable scale to ensure the supply. Sea cucumbers also have been used as bioremediation units in scenarios of high organic waste pollution from farming, such as

salmon Salmon () is the common name for several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the family (biology), family Salmonidae, which are native to tributary, tributaries of the ...

. In this instance, this carbon source is transformed into body tissue; an example of efficiently using supplies and producing an alternative culture.

References

{{Taxonbar, from=Q4305674 Monotypic echinoderm genera Holothuroidea genera Stichopodidae