Crayfish are freshwater
crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s belonging to the clade
Astacidea
Astacidea is an infraorder of decapod crustaceans including lobsters (though not "lobsters" such as the spiny lobster etc.), crayfish, and their close relatives.
Description
The Astacidea are distinguished from most other decapods by the presen ...
, which also contains
lobsters
Lobsters are a family (Nephropidae, synonym Homaridae) of marine crustaceans. They have long bodies with muscular tails and live in crevices or burrows on the sea floor. Three of their five pairs of legs have claws, including the first pair, ...
. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mudbugs, baybugs or yabbies. Taxonomically, they are members of the
superfamilies Astacoidea
Astacoidea is superfamily of freshwater crayfish that live in the Northern Hemisphere. The other superfamily of crayfish, Parastacoidea, lives in the Southern Hemisphere. Astacoidea consists of three families: Astacidae (from Europe and weste ...
and
Parastacoidea
The Parastacidae are the family of freshwater crayfish found in the Southern Hemisphere. The family is a classic Gondwana-distributed taxon, with extant members in South America, Madagascar, Australia, New Zealand, and New Guinea, and extinct ta ...
. They breathe through feather-like
gill
A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...
s. Some species are found in brooks and streams, where
fresh water
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
is running, while others thrive in
swamp
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s, ditches, and
paddy fields
A paddy field is a flooded field of arable land used for growing semiaquatic crops, most notably rice and taro. It originates from the Neolithic rice-farming cultures of the Yangtze River basin in southern China, associated with pre-Aus ...
. Most crayfish cannot tolerate
polluted water, although some species, such as ''
Procambarus clarkii
''Procambarus clarkii'', known variously as the red swamp crayfish, Louisiana crawfish or mudbug, is a species of cambarid crayfish native to freshwater bodies of northern Mexico, and southern and southeastern United States, but also introduce ...
'', are hardier. Crayfish feed on animals and plants, either living or
decomposing
Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is e ...
, and
detritus
In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...
.
The term "crayfish" is applied to saltwater species
in some countries.
Terminology
The name "crayfish" comes from the
Old French
Old French (, , ; Modern French: ) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intelligib ...
word ' (
Modern French
French ( or ) is a Romance language of the Indo-European family. It descended from the Vulgar Latin of the Roman Empire, as did all Romance languages. French evolved from Gallo-Romance, the Latin spoken in Gaul, and more specifically in No ...
').
The word has been modified to "crayfish" by association with "fish" (
folk etymology
Folk etymology (also known as popular etymology, analogical reformation, reanalysis, morphological reanalysis or etymological reinterpretation) is a change in a word or phrase resulting from the replacement of an unfamiliar form by a more famili ...
).
The largely
American
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
variant "crawfish" is similarly derived.
Some kinds of crayfish are known locally as
lobster
Lobsters are a family (biology), family (Nephropidae, Synonym (taxonomy), synonym Homaridae) of marine crustaceans. They have long bodies with muscular tails and live in crevices or burrows on the sea floor. Three of their five pairs of legs ...
s, crawdads,
mudbugs,
and
yabbies. In the
Eastern United States
The Eastern United States, commonly referred to as the American East, Eastern America, or simply the East, is the region of the United States to the east of the Mississippi River. In some cases the term may refer to a smaller area or the East C ...
, "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.
Anatomy
The body of a
decapod crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
, such as a crab, lobster, or prawn (shrimp), is made up of twenty
body segment
Segmentation in biology is the division of some animal and plant body plans into a series of repetitive segments. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, an ...
s grouped into two main body parts, the
cephalothorax
The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...
and the
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...
. Each segment may possess one pair of
appendage
An appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body.
In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including anten ...
s, although in various groups, these may be reduced or missing. On average, crayfish grow to in length. Walking legs have a small claw at the end.
Classification and geographical distribution
Crayfish are closely related to
lobsters
Lobsters are a family (Nephropidae, synonym Homaridae) of marine crustaceans. They have long bodies with muscular tails and live in crevices or burrows on the sea floor. Three of their five pairs of legs have claws, including the first pair, ...
, and together they belong to the
infraorder
Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...
Astacidea
Astacidea is an infraorder of decapod crustaceans including lobsters (though not "lobsters" such as the spiny lobster etc.), crayfish, and their close relatives.
Description
The Astacidea are distinguished from most other decapods by the presen ...
. Their
phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...
can be shown in the simplified
cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...
below:
Four
extant
Extant is the opposite of the word extinct. It may refer to:
* Extant hereditary titles
* Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English
* Extant taxon, a taxon which is not extinct, ...
(living)
families
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...
of crayfish are described, three in the
Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...
and one in the
Southern Hemisphere. The Southern Hemisphere (
Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...
-distributed) family
Parastacidae
The Parastacidae are the family of freshwater crayfish found in the Southern Hemisphere. The family is a classic Gondwana-distributed taxon, with extant members in South America, Madagascar, Australia, New Zealand, and New Guinea, and extinct ta ...
, with 14 extant genera and two extinct genera, live(d) in
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
,
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
, and
Australasia
Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologica ...
. They are distinguished by the absence of the first pair of
pleopod
The decapod ( crustaceans such as a crab, lobster, shrimp or prawn) is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various ...
s. Of the other three Northern Hemisphere families (grouped in the
superfamily
SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...
Astacoidea
Astacoidea is superfamily of freshwater crayfish that live in the Northern Hemisphere. The other superfamily of crayfish, Parastacoidea, lives in the Southern Hemisphere. Astacoidea consists of three families: Astacidae (from Europe and weste ...
), the four genera of the family
Astacidae
Astacidae is a family of freshwater crayfish native to Europe and western North America. The family is made up of four extant (living) genera: The genera ''Astacus'' (which includes the European crayfish), ''Pontastacus'' (which includes the T ...
live in western
Eurasia
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago a ...
and western
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
, the 15 genera of the family
Cambaridae
The Cambaridae are the largest of the four families of freshwater crayfish, with over 400 Species. Most of the species in the family are native the United States east of the Great Divide and Mexico, but fewer range north to Canada, and south to ...
live in eastern
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
, and the single genus of
Cambaroididae
''Cambaroides'' is a genus of freshwater crayfish from eastern Asia (eastern Russia, northeastern China, Korean Peninsula and Japan). Together with ''Astacus
''Astacus'' (from the Greek , ', meaning "lobster" or "crayfish") is a genus of c ...
live in eastern
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 ...
.
[
]
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
The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...
and the headwaters of some rivers east of the Continental Divide
A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not ...
. Many crayfish are also found in lowland areas where the water is abundant in calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
, and oxygen rises from underground springs.
In 1983, Louisiana designated the crayfish, or crawfish as they are commonly called, as its official state crustacean. Louisiana produces of crawfish per year with the red swamp and white river crawfish being the main species harvested. Crawfish are a part of Cajun
The Cajuns (; French: ''les Cadjins'' or ''les Cadiens'' ), also known as Louisiana ''Acadians'' (French: ''les Acadiens''), are a Louisiana French ethnicity mainly found in the U.S. state of Louisiana.
While Cajuns are usually described as ...
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
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
has over 100 species in a dozen 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 ...
. It is home to the world's three largest freshwater crayfish:
*the Tasmanian giant freshwater crayfish
The Tasmanian giant freshwater crayfish (''Astacopsis gouldi''), also called Tasmanian giant freshwater lobster, is the largest freshwater invertebrate and the largest freshwater crayfish species in the world. The species is only found in the rive ...
''Astacopsis gouldi'', which can achieve a mass over and is found in rivers of northern Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
*the Murray crayfish ''Euastacus armatus'', which can reach , although reports of animals up to have been made. It is found in much of the southern Murray-Darling basin.
*the marron
Marron is a name given to two closely related species of crayfish in Western Australia. Formerly considered a single species, it is now recognised as comprising two species, the critically endangered '' Cherax tenuimanus'', and the species tha ...
from 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 ...
(now believed to be two species, ''Cherax tenuimanus
''Cherax tenuimanus'', known as the hairy marron or Margaret River marron, is one of two species of crayfish in Southwestern Australia known as marron. It occupies a narrow range within the southwestern biogeographical region of Margaret Rive ...
'' and '' C. cainii'') which may reach
Many of the better-known Australian crayfish are of the genus ''Cherax'', and include the common yabby
The common yabby (''Cherax destructor'') is an Australian freshwater crustacean in the Parastacidae family (biology), family. It is listed as a vulnerable species of crayfish by the International Union for Conservation of Nature (IUCN), though ...
(''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.
New Zealand
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 ...
, two species of ''Paranephrops
''Paranephrops'' is a genus of freshwater crayfish found only in New Zealand. They are known by the English common names freshwater crayfish and koura, the latter from their Māori name of ''kōura''. The two species are the northern koura, ''Par ...
'' are endemic, and are known by the Māori
Māori or Maori can refer to:
Relating to the Māori people
* Māori people of New Zealand, or members of that group
* Māori language, the language of the Māori people of New Zealand
* Māori culture
* Cook Islanders, the Māori people of the C ...
name '.
Other animals
In Australia, New Zealand, and South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...
, the term "crayfish" or "cray" generally refers to a saltwater spiny lobster
Spiny lobsters, also known as langustas, langouste, or rock lobsters, are a family (Palinuridae) of about 60 species of achelate crustaceans, in the Decapoda Reptantia. Spiny lobsters are also, especially in Australia, New Zealand, Ireland, So ...
, of the genus ''Jasus
''Jasus'' is a genus of spiny lobsters which live in the oceans of the Southern Hemisphere. They have two distinct "horns" projecting from the front of the carapace, but lack the stridulating organs present in almost all other genera of spiny ...
'' that is indigenous to much of southern Oceania
Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...
, while the freshwater
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
species are usually called '' yabbies'' or ', from the indigenous Australian
Indigenous Australians or Australian First Nations are people with familial heritage from, and membership in, the ethnic groups that lived in Australia before British colonisation. They consist of two distinct groups: the Aboriginal peoples ...
and Māori names for the animal, respectively, or by other names specific to each species. Exceptions include western rock lobster
Western may refer to:
Places
*Western, Nebraska, a village in the US
*Western, New York, a town in the US
* Western Creek, Tasmania, a locality in Australia
*Western Junction, Tasmania, a locality in Australia
*Western world, countries that i ...
(of the Palinuridae
Spiny lobsters, also known as langustas, langouste, or rock lobsters, are a family (Palinuridae) of about 60 species of achelate crustaceans, in the Decapoda Reptantia. Spiny lobsters are also, especially in Australia, New Zealand, Ireland, So ...
family) found on the west coast of Australia (it is a spiny lobster, but not of ''Jasus)''; the Tasmanian giant freshwater crayfish
The Tasmanian giant freshwater crayfish (''Astacopsis gouldi''), also called Tasmanian giant freshwater lobster, is the largest freshwater invertebrate and the largest freshwater crayfish species in the world. The species is only found in the rive ...
(from the Parastacidae
The Parastacidae are the family of freshwater crayfish found in the Southern Hemisphere. The family is a classic Gondwana-distributed taxon, with extant members in South America, Madagascar, Australia, New Zealand, and New Guinea, and extinct ta ...
family and therefore a true crayfish) found only in Tasmania; and the Murray crayfish found along Australia's Murray River
The Murray River (in South Australia: River Murray) (Ngarrindjeri: ''Millewa'', Yorta Yorta: ''Tongala'') is a river in Southeastern Australia. It is Australia's longest river at extent. Its tributaries include five of the next six longest r ...
.
In Singapore
Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, borde ...
, the term crayfish typically refers to ''Thenus orientalis
''Thenus orientalis'' is a species of slipper lobster from the Indian Ocean, Indian and Pacific Ocean, Pacific oceans.
''T. orientalis'' is known by a number of common names. The United Nations Food and Agriculture Organization prefers the na ...
'', a seawater crustacean from the slipper lobster
Slipper lobsters are a family (Scyllaridae) of about 90 species of achelate crustaceans, in the Decapoda clade Reptantia, found in all warm oceans and seas. They are not true lobsters, but are more closely related to spiny lobsters and furry lo ...
family. True crayfish are not native to Singapore, but are commonly found as pets, or as an invasive species (''Cherax quadricarinatus
''Cherax quadricarinatus'' (known by several common names, including Australian red claw crayfish, Queensland red claw, redclaw, tropical blue crayfish, freshwater blueclaw crayfish) is an Australian freshwater crayfish.
Distribution and ecol ...
'') in the many water catchment areas, and are alternatively known as ''freshwater lobsters''.
In England 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. The only true crayfish species native to the British Isles is the endangered white clawed crayfish
''Austropotamobius pallipes'' is an endangered European freshwater crayfish, and the only crayfish native to the British Isles. Its common names include white-clawed crayfish and Atlantic stream crayfish.
Distribution
It is found from the easter ...
.
Fossil record
Fossil record
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
s of crayfish older than 30 million years are rare, but fossilised burrow
An Eastern chipmunk at the entrance of its burrow
A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of locomotion. Burrows provide a form of sh ...
s have been found from strata as old as the late Palaeozoic or early Mesozoic. The oldest records of the Parastacidae
The Parastacidae are the family of freshwater crayfish found in the Southern Hemisphere. The family is a classic Gondwana-distributed taxon, with extant members in South America, Madagascar, Australia, New Zealand, and New Guinea, and extinct ta ...
are in Australia, and are 115 million years old and the crayfish '' Palaeocambarus'' and ''Cricoidoscelosus
''Cricoidoscelosus'' is an extinct genus of crayfish discovered in the Yixian Formation in China, with only the type species, ''C. aethus'', known, that may be one of, if not, the oldest known fossil crayfish to date.Taylor, R.S., Schram, F.R ...
'' from the Yixian Formation
The Yixian Formation (; formerly transcribed as Yihsien Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the late Barremian and early Aptian stages of the Early Cretaceous. It is known for its ex ...
of China are likely around 120 million years old, making them both one of, if not, the oldest known crayfish to date.
Threats to crayfish
Crayfish are susceptible to infections such as crayfish plague
Crayfish plague (''Aphanomyces astaci'') is a water mold that infects crayfish, most notably the European ''Astacus'' which dies within a few weeks of being infected. When experimentally tested, species from Australia, New Guinea and Japan were a ...
and to environmental stressors including acidification. In Europe, they are particularly threatened by crayfish plague, which is caused by the North American water mold
Oomycota forms a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, called oomycetes (). They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the result ...
''Aphanomyces astaci.'' This water mold was transmitted to Europe when North American species of crayfish were introduced. Species of the genus ''Astacus
''Astacus'' (from the Greek , ', meaning "lobster" or "crayfish") is a genus of crayfish found in Europe and western Asia, comprising three extant (living) species and three extinct fossil species.
Due to the crayfish plague, crayfish of thi ...
'' are particularly susceptible to infection, allowing the plague-coevolved signal crayfish
The signal crayfish (''Pacifastacus leniusculus'') is a North American species of crayfish. It was introduced to Europe in the 1960s to supplement the North European ''Astacus astacus'' fisheries, which were being damaged by crayfish plague, but ...
(native to western North America) to invade parts of Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
.
Acid rain
Acid rain is rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists between 6.5 and 8.5, but acid ...
can cause problems for crayfish across the world. In whole-ecosystem experiments simulating acid rain at the Experimental Lakes Area
IISD Experimental Lakes Area (IISD-ELA, known as ELA before 2014) is an internationally unique research station encompassing 58 formerly pristine freshwater lakes in Kenora District Ontario, Canada. Previously run by Fisheries and Oceans Canada, ...
in Ontario, Canada
Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...
, crayfish populations crashed – probably because their exoskeletons
An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the ...
are weaker in acidified environments.
Invasive pest
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 the Italian agile frog.
Uses
Culinary use
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 étouffée
Étouffée or etouffee (, ) is a dish found in both Cajun and Creole cuisine typically served with shellfish over rice. The dish employs a technique known as smothering, a popular method of cooking in the Cajun and Creole areas of southwest Lo ...
s, 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.
Global crayfish production 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
Swedish cuisine () is the traditional food of Sweden. Due to Sweden's large north-to-south expanse, there are regional differences between the cuisine of North and South Sweden.
Historically, in the far north, meats such as reindeer, and other ...
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
''Nephrops norvegicus'', known variously as the Norway lobster, Dublin Bay prawn, ' (compare langostino) or ''scampi'', is a slim, orange-pink lobster which grows up to long, and is "the most important commercial crustacean in Europe". It is n ...
(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 practiced widely practiced across all spheres in Sweden and among the Swedish-speaking population of Finland
The Swedish-speaking population of Finland (whose members are called by many names; fi, suomenruotsalainen) can be used as an attribute., group=Note—see #Terminology, below; sv, finlandssvenskar; fi, suomenruotsalaiset) is a linguistic mi ...
.
In the United States, crayfish production is strongly centered in Louisiana
Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...
, 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
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 ...
. About 70–80% of crayfish produced in Louisiana are ''Procambarus clarkii
''Procambarus clarkii'', known variously as the red swamp crayfish, Louisiana crawfish or mudbug, is a species of cambarid crayfish native to freshwater bodies of northern Mexico, and southern and southeastern United States, but also introduce ...
'' (red swamp crawfish), with the remaining 20–30% being ''Procambarus zonangulus
''Procambarus zonangulus'', the white river crawfish, white river crayfish or southern white river crayfish, is a species of freshwater crayfish.
Distribution
''Procambarus zonangulus'' was originally described from Jefferson County, Hardin ...
'' (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
(also or , ) is a set of dietary laws dealing with the foods that Jewish people are permitted to eat and how those foods must be prepared according to Jewish law. Food that may be consumed is deemed kosher ( in English, yi, כּשר), fro ...
because they are aquatic animals that do not have both fin
A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...
s and scales
Scale or scales may refer to:
Mathematics
* Scale (descriptive set theory), an object defined on a set of points
* Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original
* Scale factor, a number w ...
. They are therefore not eaten by observant Jew
Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""Th ...
s.
Bait
Crayfish are preyed upon by a variety of ray-finned fish
Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species.
The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...
es, and are commonly used as bait, either live or with only the tail meat. They are a popular bait for catching catfish
Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...
, largemouth bass
The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, but ...
, smallmouth bass, striped bass
The striped bass (''Morone saxatilis''), also called the Atlantic striped bass, striper, linesider, rock, or rockfish, is an anadromous perciform fish of the family Moronidae found primarily along the Atlantic coast of North America. It has al ...
, perch
Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Percif ...
, pike
Pike, Pikes or The Pike may refer to:
Fish
* Blue pike or blue walleye, an extinct color morph of the yellow walleye ''Sander vitreus''
* Ctenoluciidae, the "pike characins", some species of which are commonly known as pikes
* ''Esox'', genus of ...
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 is important to fish in the same environment where they were caught. An Illinois State University
Illinois State University (ISU) is a public university in Normal, Illinois. Founded in 1857 as Illinois State Normal University, it is the oldest public university in Illinois. The university emphasizes teaching and is recognized as one of th ...
report that focused on studies conducted on the Fox River and Des Plaines River
The Des Plaines River () is a river that flows southward for U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed May 13, 2011 through southern Wisconsin and northern Illinois''American Her ...
watershed stated that rusty crayfish
The rusty crayfish (''Faxonius rusticus'') is a large, aggressive species of freshwater crayfish which is native to the United States, in the Ohio River Basin in parts of Ohio, Kentucky, and Indiana. Its range is rapidly expanding across much of ...
, 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 the elimination of native species. Transporting crayfish as live bait has also contributed to the spread of zebra mussels
The zebra mussel (''Dreissena polymorpha'') is a small freshwater mussel. The species originates from the lakes of southern Russia and Ukraine, but has been accidentally Introduced species, introduced to numerous other areas and has become an inv ...
in various waterways throughout Europe and North America, as they are known to attach themselves to exoskeleton of crayfishes.
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
The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propertie ...
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
''Cambarellus patzcuarensis'' is a small, threatened species of crayfish in the family Cambaridae. It is native to Mexico and often kept in aquariums.
Description
It measures in total length, including claws. Most specimens found in the wild ar ...
'', will not destructively dig or eat live aquarium plants.
In some nations, such as the United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
, United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, and 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 ...
, imported alien crayfish are a danger to local rivers. The three most widespread American species invasive in Europe are ''Faxonius limosus
''Faxonius limosus'', synonym ''Orconectes limosus'', is a species of crayfish in the family Cambaridae. It is native to the east coast of North America, from Quebec to the lower James River, Virginia, but has also been introduced to Europe. ...
'', '' Pacifastacus leniusculus'' and ''Procambarus clarkii
''Procambarus clarkii'', known variously as the red swamp crayfish, Louisiana crawfish or mudbug, is a species of cambarid crayfish native to freshwater bodies of northern Mexico, and southern and southeastern United States, but also introduce ...
''. 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
Crayfish plague (''Aphanomyces astaci'') is a water mold that infects crayfish, most notably the European ''Astacus'' which dies within a few weeks of being infected. When experimentally tested, species from Australia, New Guinea and Japan were a ...
in Europe, or the introduction of the common yabby (''Cherax destructor'') into drainages east of the Great Dividing Range in Australia.
Sentinel species
The Protivin brewery in the Czech Republic
The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...
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.
Scientists also monitor crayfish in the wild in natural bodies of water to study the levels of pollutants there.
See also
* Arthropods in culture
* Pain in crustaceans
Pain in crustaceans is a scientific debate which questions whether they experience pain or not. Pain is a complex mental state, with a distinct perceptual quality but also associated with suffering, which is an emotional state. Because of this ...
References
Further reading
*
*
*
Regional European Crayfish Workshop: Future of Native Crayfish in Europe
''Knowledge and Management of Aquatic Ecosystems
''Knowledge and Management of Aquatic Ecosystems'' is a peer-reviewed open access scientific journal covering management and conservation issues related to freshwater ecosystems. The journal publishes articles, short communications, reviews, com ...
''. No. 394–395 (2009).
*
External links
International Association of Astacology (IAA)
America's Crayfish: Crawling In Troubled Waters
Louisiana Crawfish Research and Promotion Board
*
*https://ontarionature.org/wp-content/uploads/2017/10/crayfish_apr08.pdf
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Freshwater crustaceans
Mesozoic first appearances
Articles containing video clips
Arthropod common names