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65-534: Austropotamobius is a genus of European crayfish in the family Astacidae . It contains four extant species, This crayfish article is a stub . You can help Misplaced Pages by expanding it . Crayfish Crayfish are freshwater crustaceans belonging to the infraorder Astacidea , which also contains lobsters . Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea . They breathe through feather-like gills . Some species are found in brooks and streams, where fresh water

130-505: A silt known as mulm or humus on the bottom. This material, some called undissolved organic carbon breaks down into dissolved organic carbon and can bond to heavy metal ions via chelation . It can also break down into colored dissolved organic matter such as tannin , a specific form of tannic acid . In saltwater bodies, organic material breaks down and forms a marine snow . This example of detritus commonly consists of organic materials such as dead phytoplankton and zooplankton ,

195-427: A crab, lobster, or prawn (shrimp), is made up of twenty body segments grouped into two main body parts, the cephalothorax and the abdomen . Each segment may possess one pair of appendages , although in various groups, these may be reduced or missing. On average, crayfish grow to 17.5 cm (6.9 in) in length. Walking legs have a small claw at the end. Crayfish are opportunistic omnivorous scavengers, with

260-462: A day-to-day basis, they consume what they can acquire in their immediate environment in limited space and time available - detritus . At a microbial level, the FPOM has a high surface area of organic particles and consists of a plethora of substrate and bacteria , fungi , micro-algae , meiofauna , partially decomposed organic material and mucus. This mucus or "slime" is a biofilm and can be felt on

325-407: A detritus cycle. The Monaco system , where an anaerobic layer is created in the tank, to denitrify the organic compounds in the tank, and also the other nitrogen compounds, so that the decomposition process continues until the stage where water, carbon dioxide, and nitrogen are produced, has also been implemented. Initially, as the name suggests, filtration systems in water tanks often worked using

390-499: A dozen genera . It is home to the world's three largest freshwater crayfish: Many of the better-known Australian crayfish are of the genus Cherax , and include the common yabby ( C. destructor ), western yabby ( C. preissii ), and red-claw crayfish ( C. quadricarinatus ). The marron species C. tenuimanus is critically endangered , while other large Australasian crayfish are threatened or endangered. In New Zealand , two species of Paranephrops are endemic, and are known by

455-445: A few. The exact composition of this detritus varies based on location and time of year, as it is very closely tied to primary production . Detritus occurs in a variety of terrestrial habitats including forest, chaparral and grassland. In forests, the detritus is typically dominated by leaf, twig, and bacteria litter as measured by biomass dominance. This plant litter provides important cover for seedling protection as well as cover for

520-510: A greater understanding of the creatures. The Protivin brewery in the Czech Republic uses crayfish outfitted with sensors to detect any changes in their bodies or pulse activity in order to monitor the purity of the water used in their product. The creatures are kept in a fish tank that is fed with the same local natural source water used in their brewing. If three or more of the crayfish have changes to their pulses, employees know there

585-461: A result of this process, most of the materials of dead organisms disappear and are not visible and recognizable in any form, but are present in the form of a combination of fine organic particles and the organisms that used them as nutrients . This combination is detritus. In ecosystems on land, detritus is deposited on the surface of the ground, taking forms such as the humic soil beneath a layer of fallen leaves. In aquatic ecosystems, most detritus

650-452: A similar way to mammals. Then the stress hormone cortisol is released and this leads to the formation of lactic acid in the muscles, which makes the meat taste sour. Crayfish can be cooked more humanely by first freezing them unconscious for a few hours, then destroying the central nervous system along their abdomen by cutting the crayfish lengthwise with a long knife down the center of the crayfish before cooking it. Global crayfish production

715-425: A small portion of the diet by volume. They feed on submerged vegetable material at times, but their ability to catch large living animal material is restricted. They can feed on interstitial organisms if they can be grasped in the small feeding claws. They can be lured into traps with an array of baits from dog biscuits, fish heads, meat, etc., all of which reinforces the fact that they are generalist feeders. On

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780-432: A source of nutrients, and are not suitable as a source of nutrition on their own. However, there are many microorganisms which multiply in natural environments. These microorganisms do not simply absorb nutrients from these particles, but also shape their own bodies so that they can take the resources they lack from the area around them, and this allows them to make use of excreta as a source of nutrients. In practical terms,

845-462: A variety of ray-finned fishes , and are commonly used as bait , either live or with only the tail meat. They are a popular bait for catching catfish , largemouth bass , smallmouth bass , striped bass , perch , pike and muskie . When using live crayfish as bait, anglers prefer to hook them between the eyes, piercing through their hard, pointed beak which causes them no harm; therefore, they remain more active. When using crayfish as bait, it

910-459: A variety of arthropods, reptiles and amphibians. Some insect larvae feed on the detritus. Fungi and bacteria continue the decomposition process after grazers have consumed larger elements of the organic materials, and animal trampling has assisted in mechanically breaking down organic matter. At the later stages of decomposition, mesophilic micro-organisms decompose residual detritus, generating heat from exothermic processes; such heat generation

975-418: Is a change in the water and examine the parameters. Scientists also monitor crayfish in the wild in natural bodies of water to study the levels of pollutants there. Detritus In terrestrial ecosystems detritus is present as plant litter and other organic matter that is intermixed with soil , known as soil organic matter . The detritus of aquatic ecosystems is organic substances suspended in

1040-400: Is a complex one. In land ecosystems, the waste products of plants and animals collect mainly on the ground (or on the surfaces of trees), and as decomposition proceeds, plants are supplied with fertilizer in the form of inorganic salts. In water ecosystems, relatively little waste collects on the water bed, and so the progress of decomposition in water takes a more important role. Investigating

1105-403: Is a poor source of nutrition, and so univalves pay no attention to it, but after several days, microorganisms begin to multiply on it again, its nutritional balance improves, and so they eat it again. Through this process of eating the detritus many times over and harvesting the microorganisms from it, the detritus thins out, becomes fractured and becomes easier for the microorganisms to use, and so

1170-654: Is a potential for ecological damage when crayfish are introduced into non-native bodies of water: e.g., crayfish plague in Europe, or the introduction of the common yabby ( Cherax destructor ) into drainages east of the Great Dividing Range in Australia. Some public schools in the United States keep live crayfish in the classroom and have the students take care of them in order to give the students

1235-471: Is associated with the well known phenomenon of the elevated temperature of composting . There is an extremely large number of detritus feeders in water. After all, a large quantity of material is carried in by water currents. Even if an organism stays in a fixed position, as long as it has a system for filtering water, it will be able to obtain enough food to get by. Many immobile organisms survive in this way, using developed gills or tentacles to filter

1300-471: Is caused by the North American water mold Aphanomyces astaci. This water mold was transmitted to Europe when North American species of crayfish were introduced. Species of the genus Astacus are particularly susceptible to infection, allowing the plague-coevolved signal crayfish (native to western North America) to invade parts of Europe . Acid rain can cause problems for crayfish across

1365-591: Is centered in Asia, primarily China. In 2018, Asian production accounted for 95% of the world's crawfish supply. Crayfish is part of Swedish cuisine and is usually eaten in August at special crayfish parties ( Swedish : Kräftskiva ). Documentation of the consumption of crayfish dates to at least the 16th century. On the Swedish west coast, Nephrops norvegicus ( Havskräfta , lit.   ' sea crayfish ' )

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1430-484: Is decomposed, occurs in several phases. Micro- and macro-organisms that feed on it rapidly consume and absorb materials such as proteins , lipids , and sugars that are low in molecular weight , while other compounds such as complex carbohydrates are decomposed more slowly. The decomposing microorganisms degrade the organic materials so as to gain the resources they require for their survival and reproduction. Accordingly, simultaneous to microorganisms' decomposition of

1495-751: Is found in the Pacific Northwest and the headwaters of some rivers east of the Continental Divide . Many crayfish are also found in lowland areas where the water is abundant in calcium , and oxygen rises from underground springs. Crayfish are also found in some non-coastal wetlands; eight species of crayfish live in Iowa , for example. In 1983, Louisiana designated the crayfish, or crawfish as they are commonly called, as its official state crustacean. Louisiana produces 100 million pounds (45 million kilograms) of crawfish per year with

1560-537: Is important to fish in the same environment where they were caught. An Illinois State University report that focused on studies conducted on the Fox River and Des Plaines River watershed stated that rusty crayfish , initially caught as bait in a different environment, were dumped into the water and "outcompeted the native clearwater crayfish". Other studies confirmed that transporting crayfish to different environments has led to various ecological problems, including

1625-467: Is in the end phase of decomposition and is recognised as black organic mud. The crayfish usually ingest the material in only a few minutes, as distinct from grazing for many hours. The material is mixed with digestive fluids and sorted by size. The finer particles follow a slower and more exacting route through to the hindgut , compared to the coarser material. The coarser material is eliminated first and often reappears in approximately 10 to 12 hours, whereas

1690-484: Is more commonly eaten while various freshwater crayfish are consumed in the rest of the country. Prior to the 1960s, crayfish was largely inaccessible to the urban population in Sweden and consumption was largely limited to the upper classes or farmers holding fishing rights in fresh water lakes. With the introduction of import of frozen crayfish the crayfish party is now widely practiced across all spheres in Sweden and among

1755-651: Is running, while others thrive in swamps , ditches, and paddy fields . Most crayfish cannot tolerate polluted water , although some species, such as Procambarus clarkii , are hardier. Crayfish feed on animals and plants, either living or decomposing , and detritus . The term "crayfish" is applied to saltwater species in some countries . The name "crayfish" comes from the Old French word escrevisse ( Modern French écrevisse ). The word has been modified to "crayfish" by association with "fish" ( folk etymology ). The largely American variant "crawfish"

1820-492: Is similarly derived. Some kinds of crayfish are known locally as lobsters , crawdads, mudbugs, and yabbies . In the Eastern United States , "crayfish" is more common in the north, while "crawdad" is heard more in central and southwestern regions, and "crawfish" farther south, although considerable overlaps exist. The study of crayfish is called astacology. The body of a decapod crustacean , such as

1885-498: Is suspended in water, and gradually settles. In particular, many different types of material are collected together by currents, and much material settles in slowly flowing areas. A large amount of detritus is used as a source of nutrition for animals . In particular, many bottom feeding animals ( benthos ) living in mud flats feed in this way. In particular, since excreta are materials which other animals do not need, whatever energy value they might have, they are often unbalanced as

1950-492: The Berlin Method , which employs a piece of equipment called a protein skimmer , which produces air bubbles which the detritus adheres to and forces it outside the tank before it decomposes and also a highly porous type of natural rock called live rock where many benthos and bacteria live (hermatype which has been dead for some time is often used), which causes the detritus-feeding benthos and micro-organisms to undergo

2015-622: The Italian agile frog and the painted frog in Malta . Crayfish are eaten worldwide. Like other edible crustaceans, only a small portion of the body of a crayfish is eaten. In most prepared dishes, such as soups, bisques and étouffées , only the tail portion is served. At crawfish boils or other meals where the entire body of the crayfish is presented, other portions, such as the claw meat, may be eaten. Research shows that crayfish do not die immediately when boiled alive, and respond to pain in

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2080-646: The Late Triassic (~230-200 million years ago) Chinle Formation of North America, assigned to the species " Enoploclytia " porteri and Camborygma eumekenomos, which are not assigned to any modern families. An indeterminate member of the modern family Cambaridae is known from the Late Jurassic Morrison Formation of North America. The earliest records of other modern families date to the Early Cretaceous, including

2145-531: The Māori name kōura . In Australia, New Zealand, and South Africa , the term "crayfish" or "cray" generally refers to a saltwater spiny lobster , of the genus Jasus that is indigenous to much of southern Oceania , while the freshwater species are usually called yabbies or kōura , from the indigenous Australian and Māori names for the animal, respectively, or by other names specific to each species. Exceptions include western rock lobster (of

2210-566: The National Park Service as well as video and anecdotal reports by aquarium owners indicate that crayfish will eat their moulted exoskeleton "to recover the calcium and phosphates contained in it." As omnivores, crayfish will eat almost anything; therefore, they may explore the edibility of aquarium plants in a fish tank. However, most species of dwarf crayfish, such as Cambarellus patzcuarensis , will not destructively dig or eat live aquarium plants. In some nations, such as

2275-609: The Northern Hemisphere and one in the Southern Hemisphere . The Southern Hemisphere ( Gondwana -distributed) family Parastacidae , with 14 extant genera and two extinct genera, live(d) in South America , Madagascar , and Australasia . They are distinguished by the absence of the first pair of pleopods . Of the other three Northern Hemisphere families (grouped in the superfamily Astacoidea ),

2340-692: The Palinuridae family) found on the west coast of Australia (it is a spiny lobster, but not of Jasus) ; the Tasmanian giant freshwater crayfish (from the Parastacidae family and therefore a true crayfish) found only in Tasmania; and the Murray crayfish found along Australia's Murray River . In Singapore , the term crayfish typically refers to Thenus orientalis , a seawater crustacean from

2405-679: The Swedish-speaking population of Finland . In the United States, crayfish production is strongly centered in Louisiana , with 93% of crayfish farms located in the state as of 2018. In 1987, Louisiana produced 90% of the crayfish harvested in the world, 70% of which were consumed locally. In 2007, the Louisiana crayfish harvest was about 54,800 tons, almost all of it from aquaculture . About 70–80% of crayfish produced in Louisiana are Procambarus clarkii (red swamp crawfish), with

2470-487: The United Kingdom , United States , Australia , and New Zealand , imported alien crayfish are a danger to local rivers. The three most widespread American species invasive in Europe are Faxonius limosus , Pacifastacus leniusculus and Procambarus clarkii . Crayfish may spread into different bodies of water because specimens captured for pets in one river are often released into a different catchment. There

2535-702: The parastacid Palaeoechinastacus from Australia which is 115 million years old, the cambaroidid Palaeocambarus from the Yixian Formation of China which is likely around 120 million years old ( Barremian - Aptian ), and the astacid " Austropotamobius " llopisi from the Las Hoyas site in Spain (Barremian). Crayfish are susceptible to infections such as crayfish plague and to environmental stressors including acidification. In Europe, they are particularly threatened by crayfish plague, which

2600-447: The red swamp and white river crawfish being the main species harvested. Crawfish are a part of Cajun culture dating back hundreds of years. A variety of cottage industries have developed as a result of commercialized crawfish iconography. Their products include crawfish attached to wooden plaques, T-shirts with crawfish logos, and crawfish pendants, earrings, and necklaces made of gold or silver. Australia has over 100 species in

2665-524: The slipper lobster family. True crayfish are not native to Singapore, but are commonly found as pets, or as an invasive species ( Cherax quadricarinatus ) in the many water catchment areas, and are alternatively known as freshwater lobsters . In the United Kingdom and Ireland, the terms crayfish or crawfish commonly refer to the European spiny lobster , a saltwater species found in much of

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2730-417: The water and accumulated in depositions on the floor of the body of water ; when this floor is a seabed , such a deposition is called marine snow . The remains of decaying plants or animals, or their tissue parts, and feces gradually lose their form due to physical processes and the action of decomposers , including grazers, bacteria , and fungi . Decomposition , the process by which organic matter

2795-669: The East Atlantic and Mediterranean. The only true crayfish species native to the British Isles is the endangered white clawed crayfish . Fossil burrows very similar in construction to those of modern crayfish and likely produced by early crayfish are known from the Early Permian (~300-270 million years ago) of equatorial Pangea , in what is now North America ( Washington Formation ), and Europe ( Sardinia ). The oldest body fossils assigned to crayfish are known from

2860-426: The ability to filter and process mud. In aquaculture ponds using isotope analysis they were shown to build body tissue selectively from the animal protein portion of pelleted food and not the other components of the pellet. They have the potential to eat most foods, even nutrient poor material such as grass, leaves, and paper, but can be highly selective and need variety to balance their diet. The personalities of

2925-569: The breeding and growth of marine resources . In ecosystems on land, far more essential material is broken down as dead material passing through the detritus chain than is broken down by being eaten by animals in a living state. In both land and aquatic ecosystems, the role played by detritus is too large to ignore. In contrast to land ecosystems, dead materials and excreta in aquatic ecosystems are typically transported by water flow; finer particles tend to be transported farther or suspended longer. In freshwater bodies organic material from plants can form

2990-406: The complex carbohydrates are also steadily broken down and disappear over time. What is left behind by the detritivores is then further broken down and recycled by decomposers , such as bacteria and fungi . This detritus cycle plays a large part in the so-called purification process, whereby organic materials carried in by rivers is broken down and disappears, and an extremely important part in

3055-549: The demand. In other words, during winter, plant-like organisms are inactive and collect fertilizer, but if the temperature rises to some extent they will use this up in a very short period. It is not entirely true that their productivity falls during the warmest periods. Organisms such as dinoflagellate have mobility, the ability to take in solid food, and the ability to photosynthesise. This type of micro-organism can take in substances such as detritus to grow, without waiting for it to be broken down into fertilizer. In recent years,

3120-411: The diet of these creatures was considered too complex since the first book ever written in the field of zoology, The Crayfish by T.H. Huxley (1879), where they were described as " detritivores ". This is why most researchers have not attempted to understand the diet of freshwater crayfish. The most complex study which matched the structure and function of the whole digestive track with ingested material

3185-505: The elimination of native species. Transporting crayfish as live bait has also contributed to the spread of zebra mussels in various waterways throughout Europe and North America, as they are known to attach themselves to exoskeleton of crayfishes. Crayfish are kept as pets in freshwater aquariums. They prefer foods like shrimp pellets or various vegetables, but will also eat tropical fish food, regular fish food, algae wafers, and small fish that can be captured with their claws. A report by

3250-542: The finer material is usually eliminated from 16 to 26 hours after ingestion. All waste products coming out through the hindgut are wrapped in a peritrophic membrane , so they look like a tube. Such an investment in the wrapping of the microbial free faeces in a protein rich membrane is most likely the reason they are coprophagic. Such feeding behaviour based on selection, ingestion, and extreme processing ensures periodic feeding, as distinct from continuous grazing. They tend to eat to satiation and then take many hours to process

3315-422: The four genera of the family Astacidae live in western Eurasia and western North America , the 15 genera of the family Cambaridae live in eastern North America , and the single genus of Cambaroididae live in eastern Asia . The greatest diversity of crayfish species is found in southeastern North America, with over 330 species in 15 genera, all in the family Cambaridae. A further genus of astacid crayfish

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3380-551: The individual crayfish can be a key determinant in the food preference behaviour in aquaria. Crayfish all over the world can be seen in an ecological role of benthic dwellers, so this is where most of their food is obtained - at the sediment/water interface in ponds, lakes, swamps, or burrows. When the gut contents are analysed, most of the contents is mud: fine particulate organic matter (FPOM) and mixed particles of lignin and cellulose (roots, leaves, bark, wood). Some animal material can also be identified, but this only contributes

3445-422: The level of inorganic salts in sea ecosystems shows that unless there is an especially large supply, the quantity increases from winter to spring—but is normally extremely low in summer. As such, the quantity of seaweed present reaches a peak in early summer and then decreases. The thinking is that organisms like plants grow quickly in warm periods and thus the quantity of inorganic salts is not enough to keep up with

3510-425: The material, leaving minimal chance of having more room to ingest other items. Crayfish usually have limited home range and so they rest, digest, and eliminate their waste, most commonly in the same location each day. Feeding exposes the crayfish to risk of predation, and so feeding behaviour is often rapid and synchronised with feeding processes that reduce such risks — eat, hide, process and eliminate. Knowledge of

3575-413: The materials of dead plants and animals is their assimilation of decomposed compounds to construct more of their biomass (i.e., to grow their own bodies). When microorganisms die, fine organic particles are produced. If small animals (that normally feed on microorganisms) eat these particles, the particles collect inside the intestines of the consumers, and change shape into large pellets of dung . As

3640-412: The microorganisms that multiply on it. For example, mud flats are inhabited by many univalves which are detritus feeders. When these detritus feeders take in detritus with microorganisms multiplying on it, they mainly break down and absorb the microorganisms, which are rich in proteins, and excrete the detritus, which is mostly complex carbohydrates, having hardly broken it down at all. At first, this dung

3705-470: The most important constituents of detritus are complex carbohydrates , which are persistent (difficult to break down), and the microorganisms which multiply using these absorb carbon from the detritus, and materials such as nitrogen and phosphorus from the water in their environment to synthesise the components of their own cells. A characteristic type of food chain called the detritus cycle takes place involving detritus feeders ( detritivores ), detritus and

3770-409: The outer walls of diatoms and coccolithophores, dead skin and scales of fish, and fecal pellets. This material will slowly sink to the seafloor, where it makes up the majority of sediment in some areas. Once settled, the material will not only contribute to sediments but will help to feed different species of detritivore , organisms which feed on detritus, such as annelid worms and sea cucumbers, to name

3835-437: The remaining 20–30% being Procambarus zonangulus (white river crawfish). Optimum dietary nutritional requirement of freshwater crayfish, or crayfish nutrient specifications are now available for aquaculture feed producers Like all crustaceans, crayfish are not kosher because they are aquatic animals that do not have both fins and scales . They are therefore not eaten by observant Jews . Crayfish are preyed upon by

3900-434: The surface of leaves and sticks. Also crayfish have been shown to be coprophagic - eating their own faeces, they also eat their own exuviae ( moulted carapace ) and each other. They have even been observed leaving the water to graze. Detritus or mud is a mixture of dead plankton (plant and animal), organic wastes from the water column , and debris derived from the aquatic and terrestrial environments. Mostly detritus

3965-472: The water bed do not simply suck in water through their tubes, but also extend them to fish for detritus on the surface of the bed. In contrast, from the point of view of organisms using photosynthesis such as plants and plankton , detritus reduces the transparency of the water and gets in the way of this process. Given that these organisms also require a supply of nutrient salts , in other words fertilizer , for photosynthesis, their relationship with detritus

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4030-436: The water to take in food, a process known as filter feeding . Another more widely used method of feeding, which also incorporates filter feeding, is a system where an organism secretes mucus to catch the detritus in lumps, and then carries these to its mouth using an area of cilia . Many organisms, including sea slugs and serpent's starfish, scoop up the detritus which has settled on the water bed. Bivalves which live inside

4095-440: The word detritus has also come to be used with aquariums (the word "aquarium" is a general term for any installation for keeping aquatic animals). When animals such as fish are kept in an aquarium, substances such as excreta, mucus, and dead skin cast off during moulting are produced by the animals. These substances naturally generate detritus, which is continually broken down by microorganisms. Modern sealife aquariums often use

4160-641: The world. In whole-ecosystem experiments simulating acid rain at the Experimental Lakes Area in Ontario, Canada , crayfish populations crashed – probably because their exoskeletons are weaker in acidified environments. In several countries, particularly in Europe, native species of crayfish are under threat by imported species, particularly the signal crayfish ( Pacifastacus leniusculus ). Crayfish are also considered an invasive predatory species, endangering native European species such as

4225-519: Was performed in the 1990s by Brett O'Brien on marron , the least aggressive of the larger freshwater crayfish with aquaculture potential, similar to redclaw and yabbies. Crayfish are closely related to lobsters , and together they belong to the infraorder Astacidea . Their phylogeny can be shown in the simplified cladogram below: Enoplometopidae Nephropidae Parastacidae Cambaroididae Astacidae Cambaridae Four extant (living) families of crayfish are described, three in

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