Carcinus maenas
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''Carcinus maenas'' is a common
littoral The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal a ...
crab. It is known by different names around the world. In the
British Isles The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, ...
, it is generally referred to as the shore crab, or green shore crab. In North America and
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...
, it bears the name european green crab. ''C. maenas'' is a widespread invasive species, listed among the 100 "world's worst alien invasive species". It is native to the north-east
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
and
Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and ...
, but has colonised similar habitats in Australia, South Africa,
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 sout ...
and both Atlantic and
Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
coasts of North America. It grows to a carapace width of , and feeds on a variety of mollusks, worms, and small crustaceans, potentially affecting a number of fisheries. Its successful dispersal has occurred by a variety of mechanisms, such as on ships' hulls, sea planes, packing materials, and bivalves moved for aquaculture.


Description

''C. maenas'' has a carapace up to long and wide, but can be larger outside its native range, reaching wide in
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
. The carapace has five short teeth along the rim behind each eye, and three undulations between the eyes. The undulations, which protrude beyond the eyes, are the simplest means of distinguishing ''C. maenas'' from the closely related '' C. aestuarii'', which can also be an invasive species. In ''C. aestuarii'', the carapace lacks any bumps and extends forward beyond the eyes. Another characteristic for distinguishing the two species is the form of the first and second pleopods (collectively the
gonopod Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millipe ...
s), which are straight and parallel in ''C. aestuarii'', but curve outwards in ''C. maenas''. The colour of ''C. maenas'' varies greatly, from green to brown, grey, or red. This variation has a genetic component, but is largely due to local environmental factors. In particular, individuals which delay moulting become red-coloured rather than green. Red individuals are stronger and more aggressive, but are less tolerant of environmental stresses, such as low salinity or hypoxia. Juvenile crabs on average display greater patterning than adults.


Native and introduced range

''C. maenas'' is native to European and North African coasts as far as the Baltic Sea in the east, and
Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
and
Central Norway Central Norway ( nb, Midt-Norge, nn, Midt-Noreg) is an informal region of Norway that is not clearly defined. The term ''Central Norway'' may in its most limited usage refer only to Trøndelag county, but may also be understood to include all or ...
in the north, and is one of the most common crabs throughout much of its range. In the Mediterranean Sea, it is replaced by the closely related species ''C. aestuarii''. ''C. maenas'' was first observed on the east coast of North America in
Massachusetts Massachusetts (Massachusett: ''Muhsachuweesut Massachusett_writing_systems.html" ;"title="nowiki/> məhswatʃəwiːsət.html" ;"title="Massachusett writing systems">məhswatʃəwiːsət">Massachusett writing systems">məhswatʃəwiːsət'' En ...
in 1817, and may now be found from
South Carolina )'' Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no) , anthem = " Carolina";" South Carolina On My Mind" , Former = Province of South Carolina , seat = Columbia , LargestCity = Charleston , LargestMetro = ...
northwards; by 2007, this species had extended its range northwards to
Placentia Bay Placentia Bay (french: Baie de Plaisance) is a body of water on the southeast coast of Newfoundland, Canada. It is formed by Burin Peninsula on the west and Avalon Peninsula on the east. Fishing grounds in the bay were used by native people lo ...
, Newfoundland. In 1989, the species was found in San Francisco Bay,
California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
, on the Pacific Coast of the United States. Until 1993, it was not able to extend its range, but reached
Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...
in 1997,
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...
in 1998, and
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
in 1999, thus extending its range by in 10 years. they were just south of Alaska, and were expected to enter Alaska next. By 2003, ''C. maenas'' had extended to South America with specimens discovered in
Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and g ...
. In Australia, ''C. maenas'' was first reported "in the late 1800s" in
Port Phillip Bay Port Phillip ( Kulin: ''Narm-Narm'') or Port Phillip Bay is a horsehead-shaped enclosed bay on the central coast of southern Victoria, Australia. The bay opens into the Bass Strait via a short, narrow channel known as The Rip, and is compl ...
, Victoria, although the species was probably introduced as early as the 1850s. It has since spread along the south-eastern and south-western seaboards, reaching New South Wales in 1971, South Australia in 1976 and Tasmania in 1993. One specimen was found in
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 ...
in 1965, but no further discoveries have been reported in the area since. ''C. maenas'' first reached South Africa in 1983, in the Table Docks area near
Cape Town Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...
. Since then, it has spread at least as far as
Saldanha Bay Saldanha Bay ( af, Saldanhabaai) is a natural harbour on the south-western coast of South Africa. The town that developed on the northern shore of the bay, also called Saldanha, was incorporated with five other towns into the Saldanha Bay Local ...
in the north and Camps Bay in the south, over apart. Appearances of ''C. maenas'' have been recorded in
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
,
Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...
,
Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...
,
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 ...
, the
Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...
,
Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's fifth-most populous country, with a population of almost 243 million people, and has the world's second-lar ...
, Sri Lanka, and
Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...
; however, these have not resulted in invasions, but remain isolated findings. Japan has been invaded by a related crab, either ''C. aestuarii'' or a
hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...
of ''C. aestuarii'' and ''C. maenas''. Based on the ecological conditions, ''C. maenas'' could eventually extend its range to colonise the Pacific Coast of North America from
Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...
to
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...
. Similar ecological conditions are to be found on many of the world's coasts, with the only large potential area not to have been invaded yet being
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 ...
; the New Zealand government has taken action, including the release of a Marine Pest Guide in an effort to prevent colonisation by ''C. maenas''. In 2019 ''C. maenas'' was first found in Lummi Bay, Lummi Indian Reservation,
Whatcom County, Washington Whatcom County is a county located in the northwestern corner of the U.S. state of Washington, bordered by the Canadian Lower Mainland (the Metro Vancouver and Fraser Valley Regional Districts of British Columbia) to the north, Okanogan ...
,
USA 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 territori ...
. The Nation began trapping and removing the crabs in an effort to get rid of them. Then in 2020 hundreds were found in traps, and it became clear that more intensive trapping will be necessary to keep their numbers down. Eradication will not be possible. Over a 19 year study concluding in 2020,
Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...
's
Coos Bay Coos Bay is an estuary where the Coos River enters the Pacific Ocean, the estuary is approximately 12 miles long and up to two miles wide. It is the largest estuary completely within Oregon state lines. The Coos Bay watershed covers an area of abou ...
was found to have an established and increasing population. While in 2020 less than 3,000 were trapped, trapping yielded >79,000 in 2021. This led the
Lummi The Lummi ( ; Lummi: ''Xwlemi'' ; also known as Lhaq'temish (), or ''People of the Sea''), governed by the Lummi Nation, are a Native American tribe of the Coast Salish ethnolinguistic group. They are based in the coastal area of the Pacific N ...
Indian Business Council to declare a disaster in November 2021 and the Washington Department of Fish & Wildlife to request emergency funding from the Governor.


Ecology

''C. maenas'' can live in all types of protected and semiprotected marine and estuarine habitats, including those with mud, sand, or rock substrates, submerged aquatic vegetation, and emergent
marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found a ...
, although soft bottoms are preferred. ''C. maenas'' is euryhaline, meaning that it can tolerate a wide range of
salinities Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
(from 4 to 52 
Per mille (from Latin , "in each thousand") is an expression that means parts per thousand. Other recognised spellings include per mil, per mill, permil, permill, or permille. The associated sign is written , which looks like a percent si ...
), and survive in temperatures of . The wide salinity range allows ''C. maenas'' to survive in the lower salinities found in
estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...
, and the wide temperature range allows it to survive in extremely cold climates beneath the ice in winter. A molecular biological study using the ''COI''
gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
found genetic differentiation between the North Sea and the Bay of Biscay, and even more strongly between the populations in Iceland and the
Faroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark. They are located north-northwest of Scotland, and about halfway bet ...
and those elsewhere. This suggests that ''C. maenas'' is unable to cross deeper water. Females can produce up to 185,000 eggs, and
larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...
e develop offshore in several stages before their final moult to juvenile crabs in the
intertidal The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species ...
zone. Young crabs live among seaweeds and seagrasses, such as ''
Posidonia oceanica ''Posidonia oceanica'', commonly known as Neptune grass or Mediterranean tapeweed, is a seagrass species that is endemic to the Mediterranean Sea. It forms large underwater meadows that are an important part of the ecosystem. The fruit is free f ...
'', until they reach adulthood. ''C. maenas'' has the ability to disperse by a variety of mechanisms, including
ballast water Ballast is used in ships to provide moment to resist the lateral forces on the hull. Insufficiently ballasted boats tend to tip or heel excessively in high winds. Too much heel may result in the vessel capsizing. If a sailing vessel needs to voy ...
, ships' hulls, packing materials ( seaweeds) used to ship live marine organisms, bivalves moved for aquaculture, rafting, migration of crab
larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...
e on ocean currents, and the movement of submerged aquatic vegetation for coastal zone management initiatives. ''C. maenas'' dispersed in Australia mainly by rare long-distance events, possibly caused by human actions. ''C. maenas'' is a
predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
, feeding on many organisms, particularly
bivalve molluscs Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
(such as
clam Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two shel ...
s – up to 40 clams per day,
oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not ...
s, and mussels),
polychaete Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made ...
s, and small
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 can ...
s – including other crabs up to their own size. They are primarily diurnal, although activity also depends on the tide, and crabs can be active at any time of day. In
California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
, preferential
predation Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
of ''C. maenas'' on native clams ('' Nutricola'' spp.) resulted in the decline of the native clams and an increase of a previously introduced clam (the amethyst gem clam, ''Gemma gemma''), although ''C. maenas'' also voraciously preys on introduced clams such as '' Potamocorbula amurensis''. The soft-shell clam (''
Mya arenaria Soft-shell clams (American English) or sand gaper (British English/Europe), scientific name ''Mya arenaria'', popularly called "steamers", "softshells", "piss clams", "Ipswich clams", or "Essex clams" are a species of edible saltwater clam, a ...
'') is a preferred prey species of ''C. maenas''. Consequently, it has been implicated in the destruction of the soft-shell clam fisheries on the east coast of the United States and Canada, and the reduction of populations of other commercially important bivalves (such as
scallops Scallop () is a common name that encompasses various species of Marine (ocean), marine bivalve mollusc, mollusks in the Taxonomy (biology), taxonomic Family (biology), family Pectinidae, the scallops. However, the common name "scallop" is also s ...
, ''
Argopecten irradians ''Argopecten irradians'', formerly classified as ''Aequipecten irradians'', common names Atlantic bay scallop or bay scallop, is a species of scallop in the family Pectinidae. An edible saltwater clam, it is native to the northwest Atlantic fro ...
'', and northern
quahog The hard clam (''Mercenaria mercenaria''), also known as the round clam, hard-shell (or hard-shelled) clam, or the quahog, is an edible marine bivalve mollusk that is native to the eastern shores of North America and Central America from Prince E ...
s, ''Mercenaria mercenaria''). The prey of ''C. maenas'' includes the young of bivalves and fish, although the effect of its predation on
winter flounder The winter flounder (''Pseudopleuronectes americanus''), also known as the black back, is a right-eyed ("dextral") flatfish of the family Pleuronectidae. It is native to coastal waters of the western north Atlantic coast, from Labrador, Canada to ...
, ''Pseudopleuronectes americanus'' is minimal. ''C. maenas'' can, however, have substantial negative impacts on local commercial and recreational fisheries, by preying on the young of species, such as
oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not ...
s (adults' shells are too tough for ''C. maenas'' to crack) and the
Dungeness crab The Dungeness crab (''Metacarcinus magister'') is a species of crab inhabiting eelgrass beds and water bottoms along the west coast of North America. It typically grows to across the carapace and is a popular seafood. Its common name comes f ...
, or competing with them for resources Colder water temperatures reduce overall feeding rates of ''C. maenas''. and eating the ''
Zostera marina ''Zostera marina'' is a flowering vascular plant species as one of many kinds of seagrass, with this species known primarily by the English name of eelgrass with seawrack much less used, and refers to the plant after breaking loose from the submer ...
'' that Dungeness and
juvenile salmon Fish go through various life stages between fertilization and adulthood. The life of a fish start as spawned eggs which hatch into immotile larvae. These larval hatchlings are not yet capable of feeding themselves and carry a yolk sac whic ...
depend upon for habitat. To protect itself against predators, ''C. maenas'' uses different
camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...
strategies depending on their habitat: crabs in mudflats try to resemble their surroundings with colours similar to the mud while crabs in rock pool use
disruptive coloration Disruptive coloration (also known as disruptive camouflage or disruptive patterning) is a form of camouflage that works by breaking up the outlines of an animal, soldier or military vehicle with a strongly contrasting pattern. It is often comb ...
.


Control

Due to its potentially harmful effects on ecosystems, various efforts have been made to control introduced populations of ''C. maenas'' around the world. In Edgartown, Massachusetts, a bounty was levied in 1995 for catching ''C. maenas'', to protect local shellfish, and 10 
ton Ton is the name of any one of several units of measure. It has a long history and has acquired several meanings and uses. Mainly it describes units of weight. Confusion can arise because ''ton'' can mean * the long ton, which is 2,240 pounds ...
s were caught. Some evidence shows that the native blue crab in eastern North America, ''
Callinectes sapidus ''Callinectes sapidus'' (from the Ancient Greek ,"beautiful" + , "swimmer", and Latin , "savory"), the blue crab, Atlantic blue crab, or regionally as the Chesapeake blue crab, is a species of crab native to the waters of the western Atlantic ...
'', is able to control populations of ''C. maenas''; numbers of the two species are negatively correlated, and ''C. maenas'' is not found in the
Chesapeake Bay The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the Eastern Shore of Maryland / ...
, where ''C. sapidus'' is most frequent. On the west coast of North America, ''C. maenas'' appears to be limited to upper estuarine habitats, in part because of predation by native rock crabs ('' Romaleon antennarium'' and '' Cancer productus'') and competition for shelter with a native shore crab, '' Hemigrapsus oregonensis''. Host specificity testing has recently been conducted on ''
Sacculina carcini ''Sacculina carcini'', the crab hacker barnacle, is a species of parasitic barnacle in the family Sacculinidae, in particular a parasitic castrator, of crabs. The crab that most often is used as a host is the green crab, the natural range of w ...
'', a
parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...
barnacle, as a potential biological control agent of ''C. maenas''. In the laboratory, ''Sacculina'' settled on, infected, and killed native California crabs, including the Dungeness crab, ''Metacarcinus magister'' (formerly ''Cancer magister''), and the shore crabs '' Hemigrapsus nudus'', ''Hemigrapsus oregonensis'' and ''
Pachygrapsus crassipes ''Pachygrapsus crassipes'', the striped shore crab or lined shore crab, is a small crab found on both rocky and hard-mud soft seashores of the northeastern and northwestern Pacific Ocean. In North America, this species occurs from central Orego ...
''. Dungeness crabs were the most vulnerable of the tested native species to settlement and infection by the parasite. Although ''Sacculina'' did not mature in any of the native crabs, developing reproductive sacs were observed inside a few ''M. magister'' and ''H. oregonensis'' crabs. Any potential benefits of using ''Sacculina'' to control ''C. maenas'' on the west coast of North America would need to be weighed against these potential nontarget impacts.


Use as a food

In its native range, European green crab is mostly used as an ingredient in soups and sauces. However, the closely related Mediterranean green crab ( C. aestuarii) has a thriving culinary market in Italy where fishermen known as moecante cultivate soft-shell green crabs (moeche in Venetian, moleche in Italian) and sell hard-shell crabs for their roe (masinette). Several groups in New England have successfully adapted these methods to produce soft-shell green crabs from the invasive species. In New England where invasive green crab populations are high, various groups have looked into utilizing green crabs in cuisine. In 2019, ''The Green Crab Cookbook'' was released and included recipes for soft-shell green crab, green crab roe, green crab stock, and green crab meat. One of the book's co-authors went on to found Greencrab.org, an organization dedicated to developing culinary markets for the invasive green crab. In addition to partnering with local chefs and wholesalers for supply chain development and market studies, Greencrab.org has continued to develop green crab recipes and processing techniques. Researchers at the University of Maine have actively been developing value-added green crab products, with the goals of driving business interest, stimulating a commercial green crab fishery, and alleviating predation effects. Specifically, one study evaluated the consumer acceptability of
empanadas An empanada is a type of baked or fried turnover consisting of pastry and filling, common in Spanish, other Southern European, Latin American, and Iberian-influenced cultures around the world. The name comes from the Spanish (to bread, i.e., ...
(fried, stuffed pastries) which contained varying amounts of green crab mince meat. The empanadas were rated between "like slightly" and "like moderately" for overall acceptability by a consumer panel (''n''=87). Furthermore, about two-thirds of the panelists would "probably" or "definitely" buy the empanadas if available locally. Additionally, the same researchers developed a patty product made from green crab mince meat using restructuring additives (transglutaminase, dried egg white, isolated soy protein). Although a successful green crab patty was developed, the restructuring additives may have had greater functionality in a raw crab meat system, as opposed to the fully cooked mince that was used in the present study. The results from both studies are considered promising, especially considering that these were initial rounds of green crab product development. In the past,
Legal Sea Foods Legal Sea Foods is an American restaurant chain of casual-dining seafood restaurants mostly located in the Northeastern region of the United States. The current company headquarters is located in the South Boston Seaport District and as of 202 ...
, an East Coast restaurant chain, experimented with green crabs, creating a green crab stock in their test kitchen during the winter of 2015. In June 2022 Tamworth Distilling, a New Hampshire distillery, teamed up with the University of New Hampshire's NH Green Crab Project to develop House of Tamworth Crab Trapper, which is billed as being "made with a bourbon base steeped with a custom crab, corn and spice blend mixture".


Fishery

''C. maenas'' is fished on a small scale in the northeast
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
, with about 1200 
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
s being caught annually, mostly in
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...
and the United Kingdom. In the northwest Atlantic, ''C. maenas'' was the subject of fishery in the 1960s, and again since 1996, with up to 86 tonnes being caught annually.


Taxonomic history

''Carcinus maenas'' was first given a binomial name, ''Cancer maenas'', by
Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
in his 1758
10th edition 1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. ...
of '' Systema Naturae''. An earlier description was published by
Georg Eberhard Rumphius Georg Eberhard Rumphius (originally: Rumpf; baptized c. 1 November 1627 – 15 June 1702) was a German-born botanist employed by the Dutch East India Company in what is now eastern Indonesia, and is best known for his work ''Herbarium Amboinense' ...
in his 1705 work '' De Amboinsche Rariteitkamer'', calling the species ''Cancer marinus sulcatus'', but this antedates the starting point for
zoological nomenclature The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the In ...
. A number of later synonyms have also been published: * ''Monoculus taurus'' Slabber, 1778 * ''Cancer granarius'' Herbst, 1783 * ''Cancer viridis'' Herbst, 1783 * ''Cancer pygmaeus'' Fabricius, 1787 * ''Cancer rhomboidalis'' Montagu, 1804 * ''Cancer granulatus'' Nicholls, 1943 * ''Megalopa montagui'' Leach, 1817 * ''Portunus menoides'' Rafinesque-Schmaltz, 1817 * ''Portunus carcinoides'' Kinahan, 1857 The
lectotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...
chosen for the species came from
Marstrand Marstrand () is a seaside locality situated in Kungälv Municipality, Västra Götaland County, Sweden. It had 1,320 inhabitants in 2010. The town got its name from its location on the island of Marstrand. Despite its small population, for histori ...
, Sweden, but it is assumed to have been lost. In 1814, writing for ''The Edinburgh Encyclopaedia'',
William Elford Leach William Elford Leach FRS (2 February 1791 – 25 August 1836) was an English zoologist and marine biologist. Life and work Elford Leach was born at Hoe Gate, Plymouth, the son of an attorney. At the age of twelve he began a medical appre ...
erected a new genus, ''
Carcinus ''Carcinus'' ( '' Karkinos'') is a genus of crabs, which includes ''Carcinus maenas'', an important invasive species, and '' C. aestuarii'', a species endemic to the Mediterranean Sea. ''Carcinus maenas'' ''C. maenas'' is among the 100 "worl ...
'' to hold this species alone (making it the
type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...
of the genus, by
monotypy In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...
). In 1847, Nardo described a distinct subspecies occurring in the
Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
, which is now recognised as a distinct species, '' Carcinus aestuarii''.


Neurochemistry

Particular
amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...
s in particular signaling peptides of ''C. maenas'' are
protonated In chemistry, protonation (or hydronation) is the adding of a proton (or hydron, or hydrogen cation), (H+) to an atom, molecule, or ion, forming a conjugate acid. (The complementary process, when a proton is removed from a Brønsted–Lowry acid, ...
by pH changes currently () occurring or likely to be reached in the course of future climate change. This significantly alters peptide structure and peptide-mediated behaviours (brood care and egg ventilation requiring ~10x the normal peptide concentration). The requirement of higher concentration may be due to lowered
binding affinity In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from ''ligare'', which means 'to bind'. In protein-ligand binding, the ligand is usually a m ...
in the sensory epithelium. This effect is very reversible.


Physiochemistry

The usual decrease in extracellular
chloride The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride sa ...
due to increased extracellular
bicarbonate In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial biochem ...
is avoided if ''C. maenas'' is first acclimated to the increased CO. While this may be due to the already-high extracellular chloride levels in this species, it may instead be because moderately higher CO increases these levels through some unrelated mechanism. Changes in pH due to
sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...
and
magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
can alter extracellular iron concentrations.


See also

*


References


External links


Species Profile—European Green Crab (''Carcinus maenas'')
National Invasive Species Information Center,
United States National Agricultural Library The United States National Agricultural Library (NAL) is one of the world's largest agricultural research libraries, and serves as a national library of the United States and as the library of the United States Department of Agriculture. Located ...
. Lists general information and resources for European green crab. *
2020 Salish Sea Green Crab Update
University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattl ...
Sea Grant The National Sea Grant College Program is a program of the National Oceanic and Atmospheric Administration (NOAA) within the U.S. Department of Commerce. It is a national network of 34 university-based Sea Grant programs involved in scientific re ...

2020 Coastal Green Crab Update
University of Washington Sea Grant

Maine Department of Marine Resources Maine () is a state in the New England and Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and nort ...

European green crab
Washington Department of Fish and Wildlife The Washington Department of Fish and Wildlife (WDFW) is a department of the government of the state of Washington, United States of America. The WDFW manages over a million acres of land, the bulk of which is generally open to the public, and mor ...
{{Taxonbar, from=Q27779 Crustaceans described in 1758 Crustaceans of the Atlantic Ocean Portunoidea Taxa named by Carl Linnaeus