Crayfish
Temporal range: Barremian–recent
Northern kōura, Paranephrops planifrons (Parastacidae)
Northern kōura, Paranephrops planifrons (Parastacidae)
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
(unranked): Reptantia
Infraorder: Astacidea
Superfamilies and families
Astacoidea
Parastacoidea
Rearing white-clawed crayfish at Cynrig hatchery, Wales. Establishing a breeding population from introduced captive-bred animals.
Cajun style crawfish
A man selling dried crayfish at an African market

Crayfish[a] 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 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.[1]

The term "crayfish" is applied to saltwater species in some countries.

Terminology

The name "crayfish" comes from the Old French word escrevisse (Modern French écrevisse).[2][3] The word has been modified to "crayfish" by association with "fish" (folk etymology).[2] The largely American variant "crawfish" is similarly derived.[2]

Some kinds of crayfish are known locally as lobsters,[4] crawdads,[5] mudbugs,[5] 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.[6]

The study of crayfish is called astacology.[7]

Anatomy

Main article: Decapod anatomy

The body of a decapod crustacean, such as 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.[8]

Diet

Crayfish are opportunistic omnivorous scavengers, with the ability to filter and process mud.[9] 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.[10]

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 the individual crayfish can be a key determinant in the food preference behaviour in aquaria.[citation needed]

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).[11] Some animal material can also be identified, but this only contributes 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 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 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.[10] They have even been observed leaving the water to graze.[citation needed]

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 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 the finer material is usually eliminated from 16 to 26 hours after ingestion.[12]

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 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 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 was performed in the 1990s by Brett O'Brien on marron,[12] the least aggressive of the larger freshwater crayfish with aquaculture potential, similar to redclaw and yabbies.

Classification and geographical distribution

Crayfish are closely related to lobsters, and together they belong to the infraorder Astacidea. Their phylogeny can be shown in the simplified cladogram below:[13][14][15]

Astacidea
clawed lobsters
Enoplometopoidea

Enoplometopidae

Nephropoidea

Nephropidae

crayfish
Parastacoidea

Parastacidae

Astacoidea

Cambaroididae

Astacidae

Cambaridae

Four extant (living) families of crayfish are described, three in 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.[16] Of the other three Northern Hemisphere families (grouped in the superfamily Astacoidea), 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.[14]

North America

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 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.[17] Crayfish are also found in some non-coastal wetlands; eight species of crayfish live in Iowa,[18] for example.

In 1983, Louisiana designated the crayfish, or crawfish as they are commonly called, as its official state crustacean.[19] Louisiana produces 100 million pounds (45 million kilograms) of crawfish per year with the red swamp and white river crawfish being the main species harvested.[20] Crawfish are a part of Cajun culture dating back hundreds of years.[21] 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.[22]

Australia

Australia has over 100 species in 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).[25]

The marron species C. tenuimanus is critically endangered, while other large Australasian crayfish are threatened or endangered.

New Zealand

In New Zealand, two species of Paranephrops are endemic, and are known by the Māori name kōura.[26]

Other animals

In Australia, New Zealand, and South Africa,[27] the term "crayfish" or "cray" generally refers to a saltwater spiny lobster, of the genus Jasus that is indigenous to much of southern Oceania,[28] 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 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.[citation needed]

In Singapore, the term crayfish typically refers to Thenus orientalis, a seawater crustacean from the slipper lobster family.[29][30][31] 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.[32]

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 the East Atlantic and Mediterranean.[33] The only true crayfish species native to the British Isles is the endangered white clawed crayfish.[34][35]

Fossil record

When crayfish originated is unknown, though fossil burrows possibly created by crayfish have been found from strata as old as the Permian.[36][37][38] The oldest unambiguous fossil records of crayfish date to the Early Cretaceous, including the parastacid Palaeoechinastacus from Australia which is 115 million years old,[39] the cambaroidid Palaeocambarus from the Yixian Formation of China which is likely around 120 million years old (Barremian-Aptian),[38] and the astacid Austropotamobius llopisi from the Las Hoyas site in Spain (Barremian).[40]

Threats to crayfish

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 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.[41] 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.[42]

Acid rain can cause problems for crayfish across 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.[43]

Invasive pest

In several countries, particularly in Europe, native species of crayfish are under threat by imported species, particularly the signal crayfish (Pacifastacus leniusculus).[44] [45] Crayfish are also considered an invasive predatory species, endangering native European species such as the Italian agile frog.

Uses

Human uses
Crayfish, boiled with potatoes and corn
A pet crayfish, Procambarus clarkii in a freshwater aquarium
Golden crayfish pendant, Chiriqui, Panama, c. 11th to 16th century AD

Culinary use

Main article: Crayfish as food

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.[citation needed]

Research shows that crayfish do not die immediately when boiled alive, and respond to pain in 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.[46]

Global crayfish production is centered in Asia, primarily China. In 2018, Asian production accounted for 95% of the world's crawfish supply. [47]

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 (Swedish Havskräfta, sea crayfish) 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 the Swedish-speaking population of Finland.[48]

In the United States, crayfish production is strongly centered in Louisiana, with 93% of crayfish farms located in the state as of 2018.[49] In 1987, Louisiana produced 90% of the crayfish harvested in the world, 70% of which were consumed locally.[50] In 2007, the Louisiana crayfish harvest was about 54,800 tons, almost all of it from aquaculture.[51] About 70–80% of crayfish produced in Louisiana are Procambarus clarkii (red swamp crawfish), with the remaining 20–30% being Procambarus zonangulus (white river crawfish).[52] Optimum dietary nutritional requirement of freshwater crayfish, or crayfish nutrient specifications are now available for aquaculture feed producers [53]

Like all crustaceans, crayfish are not kosher because they are aquatic animals that do not have both fins and scales.[54] They are therefore not eaten by observant Jews.[55]

Bait

Crayfish are preyed upon by a variety of ray-finned fishes,[56] and are commonly used as bait, either live or with only the tail meat. They are a popular bait for catching catfish,[57] largemouth bass, smallmouth bass, striped bass,[58] perch, pike[59] 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.[60]

When using crayfish as bait, it 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".[61] Other studies confirmed that transporting crayfish to different environments has led to various ecological problems, including the elimination of native species.[62] 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.[63][64][65]

Pets

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 the National Park Service[66] as well as video and anecdotal reports by aquarium owners[67] indicate that crayfish will eat their moulted exoskeleton "to recover the calcium and phosphates contained in it."[66] 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.[68]

In some nations, such as 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.[41] Crayfish may spread into different bodies of water because specimens captured for pets in one river are often released into a different catchment. There 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.[69]

Sentinel species

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 is a change in the water and examine the parameters.[70]

Scientists also monitor crayfish in the wild in natural bodies of water to study the levels of pollutants there.[70][71][72]

See also

Notes

  1. ^ In some locations, they are also known as baybugs, crabfish, craws, crawfish, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, mudbugs, rock lobsters, signal crawfish, or yabbies.

References

  1. ^ Christoph Needon; Johannes Petermann; Peter Scheffel; Bernd Scheibe (1971). Plants and Animals (Pflanzen und Tiere). Leipzig: Urania Verlag.
  2. ^ a b c "crayfish". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  3. ^ Wedgwood, Hensleigh (1855). "On False Etymologies". Transactions of the Philological Society (6): 65.
  4. ^ C. W. Hart Jr. (1994). "A dictionary of non-scientific names of freshwater crayfishes (Astacoidea and Parastacoidea), including other words and phrases incorporating crayfish names". Smithsonian Contributions to Anthropology. 38 (38): 1–127. doi:10.5479/si.00810223.38.1. hdl:10088/1372. S2CID 86017542.
  5. ^ a b Pableaux Johnson. "Mudbug Madness : Crawfish". Bayou Dog. Archived from the original on 19 August 2006. Retrieved 28 August 2006.
  6. ^ Bert Vaux; Scott A. Golder. "Dialect survey". Harvard University. Retrieved 30 September 2006.
  7. ^ "About the International Association of Astacology". Archived from the original on 5 April 2005.
  8. ^ "What Is the Difference Between Walking Legs and Chelipeds in Crayfish?". Pets on Mom.com. Retrieved 12 June 2021.
  9. ^ O'Brien, Brett G. (1990). "Feeding Biology of Marron Cherax tenuimanus Decapoda: Parastacidae". National Symposium of Freshwater Crayfish Culture Proceedings: 89–104.
  10. ^ a b O'Brien, B.G.; Davies, P.M. (2002). "The structure of marron (Cherax tenuimanus) food webs in commercial ponds: results from multiple stable isotope analyses". Freshwater Crayfish. 13 (1): 155–163.
  11. ^ O'Brien, Brett G. (1995). "The natural diet of the freshwater crayfish Cherax tenuimanus (Smith 1912) (Decapoda: Parastacidae) as determined by gut content analysis". Freshwater Crayfish. 10 (1): 151-162.
  12. ^ a b O'Brien, Brett G. (1994). The Feeding Biology of Marron. The University of Western Australia. p. 273.
  13. ^ Wolfe, Joanna M.; Breinholt, Jesse W.; Crandall, Keith A.; Lemmon, Alan R.; Lemmon, Emily Moriarty; Timm, Laura E.; Siddall, Mark E.; Bracken-Grissom, Heather D. (24 April 2019). "A phylogenomic framework, evolutionary timeline and genomic resources for comparative studies of decapod crustaceans". Proceedings of the Royal Society B. 286 (1901). doi:10.1098/rspb.2019.0079. PMC 6501934. PMID 31014217.
  14. ^ a b Crandall, Keith A.; De Grave, Sammy (2017). "An updated classification of the freshwater crayfishes (Decapoda: Astacidea) of the world, with a complete species list". Journal of Crustacean Biology. 37 (5): 615–653. doi:10.1093/jcbiol/rux070.
  15. ^ Heather D. Bracken-Grissom; Shane T. Ahyong; Richard D. Wilkinson; Rodney M. Feldmann; Carrie E. Schweitzer; Jesse W. Breinholt; Matthew Bendall; Ferran Palero; Tin-Yam Chan; Darryl L. Felder; Rafael Robles; Ka-Hou Chu; Ling-Ming Tsang; Dohyup Kim; Joel W. Martin; Keith A. Crandall (July 2014). "The Emergence of Lobsters: Phylogenetic Relationships, Morphological Evolution and Divergence Time Comparisons of an Ancient Group (Decapoda: Achelata, Astacidea, Glypheidea, Polychelida)". Systematic Biology. 63 (4): 457–479. doi:10.1093/sysbio/syu008. PMID 24562813.
  16. ^ Horton H. Hobbs Jr. (1974). "Synopsis of the families and genera of crayfishes (Crustacea: Decapoda)". Smithsonian Contributions to Zoology. 164 (164): 1–32. doi:10.5479/si.00810282.164. S2CID 86685246.
  17. ^ Steve Pollock (2005). Eyewitness Ecology. New York, United States: Dorling Kindersley. ISBN 978-0-7894-5581-9.
  18. ^ "What's a Mudbug?" (Press release). Iowa Department of Natural Resources. 12 July 2022.
  19. ^ "The Crawfish – Louisiana's State Crustacean". American Profile. 11 August 2002. Retrieved 25 November 2017.
  20. ^ "Crawfish Louisiana State Crustacean". State of Louisiana-Department of Administration. 3 June 2014. Retrieved 25 November 2017.
  21. ^ "Crawfish Deeply Rooted in Louisiana Culture". Voice of America. 19 April 2016. Retrieved 25 November 2017.
  22. ^ Gutierrez, C. Paige (1 January 2012). Cajun Foodways. University Press of Mississippi. p. 78. ISBN 9781604736021. Retrieved 25 November 2017.
  23. ^ "Tasmanian Giant Freshwater Lobster (Astacopsis gouldi)". Department of the Environment, Water, Heritage and the Arts. 9 February 2007. Retrieved 16 March 2010.
  24. ^ Fisheries Scientific Committee (2013). "The Murray crayfish – Euastacus armatus as a Vulnerable Species" (PDF). NSW Department of Primary Industries. Archived (PDF) from the original on 1 April 2015. Retrieved 11 March 2019.
  25. ^ Michael P. Masser; David B. Rouse (1997). "Australian Red Claw Crayfish" (PDF). SRAC Publication (244). Archived from the original (PDF) on 13 May 2005.
  26. ^ "Kōura". NIWA. 26 May 2009. Retrieved 18 September 2012.
  27. ^ "Lobsters, rock lobsters and crayfish". Western Australian Museum. Retrieved 30 November 2019.
  28. ^ Harold W. Sims Jr. (1965). "Let's call the spiny lobster "spiny lobster"". Crustaceana. 8 (1): 109–110. doi:10.1163/156854065X00613. JSTOR 20102626.
  29. ^ "Sweet Chilli Crayfish (龙马精神)". mywoklife.com. 13 February 2010.
  30. ^ "FAR OCEAN SEA PRODUCTS (PRIVATE) LIMITED". dollarvietnam.com.
  31. ^ Classic Asian Noodles. Marshall Cavendish. 2007. ISBN 978-9812613356.
  32. ^ Shane T. Ahyong; Darren C. J. Yeo (2007). "Feral populations of the Australian Red-Claw crayfish (Cherax quadricarinatus von Martens) in water supply catchments of Singapore". Biol Invasions. 9 (8): 943–946. Bibcode:2007BiInv...9..943A. doi:10.1007/s10530-007-9094-0.
  33. ^ "European spiny lobster (Palinurus elephas)". The Marine Life Information Network. Archived from the original on 7 April 2016. Retrieved 17 October 2021.
  34. ^ "White-clawed (or Atlantic stream) crayfish (Austropotamobius pallipes) - Special Areas of Conservation". sac.jncc.gov.uk. Retrieved 17 October 2021.
  35. ^ "White-clawed crayfish | Shropshire Wildlife Trust". www.shropshirewildlifetrust.org.uk. Retrieved 17 October 2021.
  36. ^ Alycia L. Rode & Loren E. Babcock (2003). "Phylogeny of fossil and extant freshwater crayfish and some closely related nephropid lobsters". Journal of Crustacean Biology. 23 (2): 418–435. doi:10.1651/0278-0372(2003)023[0418:POFAEF]2.0.CO;2. JSTOR 1549646. S2CID 198968671.
  37. ^ Baucon, A., Ronchi, A., Felletti, F., Neto de Carvalho, C. 2014. Evolution of Crustaceans at the edge of the end-Permian crisis: ichnonetwork analysis of the fluvial succession of Nurra (Permian-Triassic, Sardinia, Italy). Palaeogeography, Palaeoclimatology, Palaeoecology, 410. Abstract available at http://www.tracemaker.com
  38. ^ a b "Crayfishes from the Jehol biota". Geodiversitas. 45 (24): 689–719. 2023.
  39. ^ Martin, Anthony J.; Rich, Thomas H.; Poore, Gary C.B.; Schultz, Mark B.; Austin, Christopher M.; Kool, Lesley; Vickers-Rich, Patricia (2008). "Fossil evidence in Australia for oldest known freshwater crayfish of Gondwana". Gondwana Research. 14 (3): 287–296. Bibcode:2008GondR..14..287M. doi:10.1016/j.gr.2008.01.002. ISSN 1342-937X.
  40. ^ García-Penas, Álvaro; Ferratges, Fernando Ari; Moreno-Bedmar, Josep Anton; Bover-Arnal, Telm; Gasca, José Manuel; Aurell, Marcos; Zamora, Samuel (2023). "Decapod crustaceans from the Lower Cretaceous of Spain, with an account of new occurrences in Barremian-Aptian strata of the Maestrazgo Basin". Cretaceous Research. 150: 105576. Bibcode:2023CrRes.15005576G. doi:10.1016/j.cretres.2023.105576. ISSN 0195-6671.
  41. ^ a b James R. Lee (5 December 1998). "TED Case Studies Crayfish Plague #478 European Crayfish Dispute". Archived from the original on 10 January 2009. Retrieved 20 January 2008.
  42. ^ "Nonindigenous Aquatic Species - Pacifastacus leniusculus". Retrieved 6 July 2020.
  43. ^ "A Canadian Scientist Explains How Acid Rain is Still Making its Mark". IISD Experimental Lakes Area. 16 May 2018. Retrieved 6 July 2020.
  44. ^ "Invading Europe's waterways: The crayfish occupation". 19 December 2019.
  45. ^ "Invasive species: Why Britain can't eat its way out of its crayfish problem".
  46. ^ Nyheter, S. V. T.; Alström, Vivvi (12 August 2023). "Forskning visar: Kräftor känner smärta när de kokas levande". SVT Nyheter (in Swedish). Retrieved 12 August 2023.
  47. ^ "Global Aquaculture Production: Procambarus clarkii, 1990-2018". FAO Fisheries Division. Food And Agriculture Organization of the United Nations. Retrieved 21 March 2021.
  48. ^ Po Tidhom (2004). "The Crayfish Party". The Swedish Institute. Archived from the original on 4 February 2009. Retrieved 29 January 2006.
  49. ^ "Table 18. Crustacean Sales by Species: 2018 and 2013" (PDF). 2018 Census of Agriculture. USDA, National Agricultural Statistics Service. Archived (PDF) from the original on 19 December 2019. Retrieved 21 March 2021.
  50. ^ Larry W. de la Bretonne Jr. & Robert P. Romaire (1990). "Crawfish production: harvesting, marketing and economics" (PDF). SRAC Publication (242). Archived from the original (PDF) on 12 December 2010.
  51. ^ "1978–2007: Louisiana Summary of Agriculture and Natural Resources" (PDF). Louisiana State University Agricultural Center, Baton Rouge, Louisiana. 2009. Archived from the original (PDF) on 2 April 2012.
  52. ^ "Differences Between Red Swamp Crawfish and White River Crawfish". The Louisiana State University Agricultural Center. Archived from the original on 18 July 2011. Retrieved 25 February 2009.
  53. ^ Lunda, Roman; Roy, Koushik; Dvorak, Petr; Kouba, Antonin; Mraz, Jan (2020). "Recycling biofloc waste as novel protein source for crayfish with special reference to crayfish nutritional standards and growth trajectory". Scientific Reports. 10 (1): 19607. Bibcode:2020NatSR..1019607L. doi:10.1038/s41598-020-76692-0. PMC 7658255. PMID 33177672.
  54. ^ "Kosher defined". Triangle K. Retrieved 1 December 2010.
  55. ^ Meyer-Rochow, Victor Benno (2009). "Food taboos: their origins and purposes". Journal of Ethnobiology and Ethnomedicine. 5–18: 18. doi:10.1186/1746-4269-5-18. PMC 2711054. PMID 19563636.
  56. ^ Web, Animal Diversity (16 September 2002). "Kids' Inquiry of Diverse Species, Orconectes propinquus, northern clearwater crayfish: INFORMATION". BioKIDS. Retrieved 27 July 2018.
  57. ^ Samsel, Jeff (5 August 2005). "5 Great Catfish Baits". Game & Fish. Archived from the original on 8 November 2021. Retrieved 13 February 2021.
  58. ^ "Striped Bass Feeding Facts and Information". Bass Fishing Gurus. 4 March 2015. Retrieved 27 July 2018.
  59. ^ "The Key to Locating Bass, Walleye or Pike". Funny Fishing Tshirts & Fishing Gifts – Fish Face. 25 August 2017. Archived from the original on 27 July 2018. Retrieved 27 July 2018.
  60. ^ Bean, Richard Alden (6 April 2011). "Crayfish: What Better Spring Bait For Bass?". Game & Fish. Retrieved 27 July 2018.
  61. ^ "Fox and Des Plaines Rivers Watershed" (PDF). Critical Trends in Illinois Ecosystems. Illinois Department of Natural Resources. 2001. Archived from the original (PDF) on 27 March 2009. Retrieved 10 February 2009.
  62. ^ Tennessee Aquatic Nuisance Species Task Force (2007). Tennessee Aquatic Nuisance Species Management Plan (PDF). Tennessee Wildlife Resources Agency. Archived (PDF) from the original on 9 September 2008.
  63. ^ "Hawaii Risk Analyses and Management for Dreissenid Mussels" (PDF). US Fish & Wildlife. 2012. p. 3. Archived (PDF) from the original on 30 October 2014. Retrieved 27 July 2018.
  64. ^ "zebra mussel (Dreissena polymorpha) – Species Profile". Nonindigenous Aquatic Species. 16 November 2005. Retrieved 27 July 2018.
  65. ^ J. Thompson; F. Parchaso; A. Alpine; J. Cloern; B. Cole; O. Mace; J. Edmunds; J. Baylosis; S. Luoma; F. Nichols (13 December 2007). "The History and Effects of Exotic Species in San Francisco Bay". United States Geological Survey. Archived from the original on 1 July 2013. Retrieved 10 February 2009.
  66. ^ a b abebault (May 2013). "Crayfish Facts". Google. Retrieved 27 July 2018.
  67. ^ "YouTube". YouTube. 12 April 2018. Archived from the original on 30 October 2021. Retrieved 27 July 2018.
  68. ^ Gerald Pottern. "Mexican dwarf orange crayfish, Cambarellus patzcuarensis". Archived from the original on 28 July 2018. Retrieved 13 October 2010.
  69. ^ Coughran, J; Mccormack, R; Daly, G (2009). "Translocation of the Yabby Cherax destructor into eastern drainages of New South Wales, Australia". Australian Zoologist. 35: 100–103. doi:10.7882/AZ.2009.009. Retrieved 10 May 2018.
  70. ^ a b Hanrahan, Mark (27 September 2017). "Crayfish staff help Czech brewery keep its water as pure as can be". Reuters TV. Archived from the original on 25 October 2019. Retrieved 25 October 2019.
  71. ^ "Clean Water". Missouri Conservationist Magazine. Vol. 69, no. 11. Missouri Department of Conservation. November 2008. Archived from the original on 25 October 2019. Retrieved 25 October 2019.
  72. ^ Schilderman, P. A. E. L.; Moonen, E. J. C.; Maas, L. M.; Welle, I.; Kleinjans, J. C. S. (1999). "Use of Crayfish in Biomonitoring Studies of Environmental Pollution of the River Meuse". Ecotoxicology and Environmental Safety. 44 (3): 241–252. doi:10.1006/eesa.1999.1827. ISSN 0147-6513. PMID 10581118.

O’Brien, B.G. (1994). The natural diet of the freshwater crayfish Cherax tenuimanus (Smith 1912) Decapoda:parastacidae) as determined by gut content analysis. Freshwater Crayfish 10, 151-162.

Further reading