Carcinus maenas is a common
littoralThe littoral zone is that part of a sea, lake or river that is close to the shore. In coastal environments the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged. It always includes this intertidal zone and is often used to...
crabTrue crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
, and an important
invasive species"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
, listed among the 100 "world's worst alien invasive species". It is native to the north-east
Atlantic OceanThe Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
and
Baltic SeaThe Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
, but has colonised similar habitats in Australia, South Africa, South America and both Atlantic and
PacificThe Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
coasts of North America. It grows to a
carapaceA carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
width of 90 millimetres (3.5 in), and feeds on a variety of
molluscsThe Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
, worms and small crustaceans, potentially impacting a number of fisheries. Its successful dispersion has occurred via a variety of mechanisms, such as on ships' hulls, packing materials, bivalves moved for
aquacultureAquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...
, and rafting.
C. maenas is known by different names around the world. In the
British IslesThe British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
, it is generally referred to simply as the
shore crab. In
North AmericaNorth America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and
South AfricaThe Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, it bears the name
green crab or
European green crab. In
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and
New ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, it is referred to as either the
European green crab or
European shore crab.
Description
C. maenas has a
carapaceA carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
up to 60 millimetres (2.4 in) long and 90 mm (3.5 in) wide, with 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. aestuariiCarcinus aestuarii is a littoral crab, native to the Mediterranean Sea. It bears some similarities to Carcinus maenas and was sometimes considered to be a subspecies thereof, rather than a species in its own right, but a molecular biological study using the COI gene found the difference between the...
, 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 gonopods), 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
moultingEcdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...
become red–coloured rather than green. Red individuals are stronger and more aggressive, but are less tolerant of environmental stresses, such as low
salinitySalinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
or
hypoxiaHypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
.
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 and central Norway 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
Carcinus aestuarii.
C. maenas was first observed on the east coast of North America in
MassachusettsThe Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
in 1817, and may now be found from southern
VirginiaThe Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
northwards; by 2007, this species had extended its range northwards to
Placentia BayPlacentia Bay 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 long before the first European fishermen arrived in the 16th century. For a time, the...
,
NewfoundlandNewfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...
. In 1989, the species was found in
San Francisco BaySan Francisco Bay is a shallow, productive estuary through which water draining from approximately forty percent of California, flowing in the Sacramento and San Joaquin rivers from the Sierra Nevada mountains, enters the Pacific Ocean...
,
CaliforniaCalifornia is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, on the Pacific coast of the United States. Until 1993, it was not able to extend its range, but reached
OregonOregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
in 1997, the state of Washington in 1998 and
British ColumbiaBritish Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
in 1999, thus extending its range by 750 kilometres (466 mi) in ten years. By 2003,
C. maenas had extended to South America with specimens discovered in
PatagoniaPatagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
.
In Australia,
C. maenas was first reported "in the late 1800s", in Port Phillip Bay, Victoria. 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 AustraliaWestern Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
in 1965, but there have been no further discoveries in the area since.
C. maenas first reached South Africa in 1983, in the Table Docks area near
Cape TownCape Town is the second-most populous city in South Africa, and the provincial capital and primate city of the Western Cape. As the seat of the National Parliament, it is also the legislative capital of the country. It forms part of the City of Cape Town metropolitan municipality...
. Since then, it has spread at least as far as
Saldanha BaySaldanha Bay is a natural harbour on the south-western coast of South Africa, north west of Cape Town. 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 Municipality in 2000. The current population of...
in the north and
Camps BayCamps Bay is an affluent suburb of Cape Town, South Africa. In summer it attracts a large number of foreign visitors as well as South Africans looking for a beach holiday. It is renowned for its white sandy beaches fringed by palm trees and has a trendy nightlife.-History:The first residents of...
in the south, over 100 kilometres (62.1 mi) apart.
There have been appearances of
C. maenas recorded in Brazil, Panama, Hawaii,
MadagascarThe Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, the
Red SeaThe Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
,
PakistanPakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
,
Sri LankaSri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
and
MyanmarBurma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....
; however, these have not resulted in invasions, but remain isolated findings. Japan has been invaded by a related crab, either
C. aestuariiCarcinus aestuarii is a littoral crab, native to the Mediterranean Sea. It bears some similarities to Carcinus maenas and was sometimes considered to be a subspecies thereof, rather than a species in its own right, but a molecular biological study using the COI gene found the difference between the...
or a hybrid of
C. aestuarii and
C. maenas.
It is believed, based on the ecological conditions, that
C. maenas could eventually extend its range to colonise the Pacific coast of North America from
Baja CaliforniaBaja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
to
AlaskaAlaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
. 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 ZealandNew Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
; the New Zealand government has taken action, including the release of a Marine Pest Guide in an effort to prevent colonisation by
C. maenas.
Ecology
C. maenas can live in all types of protected and semi-protected marine and estuarine habitats, including habitats with mud, sand, or rock substrates, submerged aquatic vegetation, and emergent
marshIn geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....
, although soft bottoms are preferred.
C. maenas is
euryhalineEuryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the molly which can live in fresh, brackish, or salt water. The European shore crab is an example of a euryhaline invertebrate that can live in salt and brackish water...
, meaning that it can tolerate a wide range of
salinitiesSalinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
(from 4 to 52
‰A per mil or per mille is a tenth of a percent or one part per thousand. It is written with the sign ‰ , which looks like a percent sign with an extra zero at the end...
), and survive in temperatures of 0 to 30 °C (32 to 86 F). The wide salinity range allows
C. maenas to survive in the lower salinities found in
estuariesAn estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
. A
molecular biologicalMolecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...
study using the COI
geneA gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
found genetic differentiation between the North Sea and the
Bay of BiscayThe Bay of Biscay is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal, and is named in English after the province of Biscay, in the Spanish...
, and even more strongly between the populations in Iceland and the
Faroe IslandsThe Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...
and those elsewhere. This suggests that
C. maenas is unable to cross deeper water.
Females can produce up to 185,000 eggs, and
larvaA larva 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 zone. Young crabs live among seaweeds and seagrasses, such as
Posidonia oceanicaPosidonia oceanica 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 floating and known in Italy as 'the olive of the sea'...
, until they reach adulthood.
C. maenas has the ability to disperse by a variety of mechanisms, including
ballast waterBallast is used in sailboats to provide moment to resist the lateral forces on the sail. Insufficiently ballasted boats will tend to tip, or heel, excessively in high winds. Too much heel may result in the boat capsizing. If a sailing vessel should need to voyage without cargo then ballast of...
, ships' hulls, packing materials (
seaweedSeaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
s) used to ship live marine organisms, bivalves moved for
aquacultureAquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...
, rafting, migration of crab
larvaA larva 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. Thresher
et al. found
C. maenas dispersed in Australia mainly by rare long-distance events, possibly caused by human actions.
C. maenas is a predator, feeding on many organisms, particularly
bivalve molluscsBivalvia is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells...
(such as
clamThe word "clam" can be applied to freshwater mussels, and other freshwater bivalves, as well as marine bivalves.In the United States, "clam" can be used in several different ways: one, as a general term covering all bivalve molluscs...
s,
oysterThe word oyster is used as a common name for a number of distinct groups of bivalve molluscs which live in marine or brackish habitats. The valves are highly calcified....
s, and
musselThe common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.The...
s),
polychaeteThe Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
s and small
crustaceanCrustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s. They are primarily nocturnal, although activity also depends on the tide, and crabs can be active at any time of day. In
CaliforniaCalifornia is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, preferential
predationIn ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
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 gemmaThe amethyst gem clam, Gemma gemma, is a small species of marine bivalve mollusk. It is a member of the family Veneridae, the Venus clams.It is one of the smaller species of marine clam, reaching a length of only 5 mm...
).
C. maenas has been implicated in the destruction of the soft-shell clam (
Mya arenaria) fisheries on the east coast of the United States and Canada, and the reduction of populations of other commercially important bivalves (such as scallops,
Argopecten irradiansArgopecten irradians, formerly classified as Aequipecten irradians, common names the "Atlantic bay scallop" or "bay scallop", is an edible species of saltwater clam, a scallop, a marine bivalve mollusk in the family Pectinidae, the scallops....
, and northern quahogs,
Mercenaria mercenaria). The prey of
C. maenas includes the young of bivalves and fish, although the effect of its predation on
winter flounderThe winter flounder, Pseudopleuronectes americanus, is a right-eyed flatfish of the family Pleuronectidae. It is native to coastal waters of the western north Atlantic coast, from Labrador, Canada to Georgia, United States...
,
Pseudopleuronectes americanus is minimal.
C. maenas can, however, have substantial negative impacts on local commercial and recreational
fisheriesGenerally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
, by preying on the young of species, such as
oysterThe word oyster is used as a common name for a number of distinct groups of bivalve molluscs which live in marine or brackish habitats. The valves are highly calcified....
s and the
Dungeness crabThe Dungeness crab, Metacarcinus magister , is a species of crab that inhabits eelgrass beds and water bottoms on the west coast of North America. It typically grows to across the carapace and is a popular seafood...
, or competing with them for resources.
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
shellfishShellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
, and 10
tonThe ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...
s were caught.
There is evidence that the native blue crab in eastern North America,
Callinectes sapidus, is able to control populations of
C. maenas; numbers of the two species are
negatively correlatedIn statistics, dependence refers to any statistical relationship between two random variables or two sets of data. Correlation refers to any of a broad class of statistical relationships involving dependence....
, and
C. maenas is not found in the
Chesapeake BayThe Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West...
, where
Callinectes 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 productusCancer productus, one of several species known as the red rock crab, is a crab of the genus Cancer found on the western coast of North America.- Description :...
) and competition for shelter with a native shore crab,
Hemigrapsus oregonensisHemigrapsus oregonensis is a small shore crab of the family Varunidae; it was formerly classified under the family Grapsidae. It is known under several common names, including yellow shore crab, hairy shore crab, green shore crab, mud-flat crab, and Oregon shore crab.Despite its name, the body...
. Host specificity testing has recently been conducted on
Sacculina carciniSacculina is a genus of barnacles that is a parasitic castrator of crabs. The adults bear no resemblance to the barnacles that cover ships and piers; they are recognised as barnacles because their larval forms are like other members of the barnacle class Cirripedia...
, a parasitic
barnacleA barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have...
, as a potential biological control agent of
C. maenas. In the laboratory,
Sacculina settled on, infected, and killed native California crabs, including the
Dungeness crabThe Dungeness crab, Metacarcinus magister , is a species of crab that inhabits eelgrass beds and water bottoms on the west coast of North America. It typically grows to across the carapace and is a popular seafood...
,
Metacarcinus magister (formerly
Cancer magister), and the shore crabs
Hemigrapsus nudusThe purple shore crab, Hemigrapsus nudus, is a common crab of the family Varunidae. It can be found sheltering under rocks in inter-tidal areas along the west coast of North America, from Alaska to Baja California in Mexico. This crab primarily eats sea lettuce and other green algae, and...
,
Hemigrapsus oregonensis and
Pachygrapsus crassipes. 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
Metacarcinus magister and
Hemigrapsus oregonensis. 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 non-target impacts.
Fishery
C. maenas is fished on a small scale in the north-east
Atlantic OceanThe Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, with approximately 1200
tonneThe tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s being caught annually, mostly in France 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 nameBinomial nomenclature is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages...
,
Cancer maenas, by Carl Linnaeus in his 1758 tenth edition of
Systema NaturaeThe book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
. An earlier description was published by
Georg Eberhard RumphiusGeorg Eberhard Rumphius or originally Rumpf 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 predates the starting point for zoological nomenclature. A number of later
synonymsIn scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
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
lectotypeIn botanical nomenclature and zoological nomenclature, a lectotype is a kind of name-bearing type. When a species was originally described on the basis of a name-bearing type consisting of multiple specimens, one of those may be designated as the lectotype...
chosen for the species came from
MarstrandMarstrand is a seaside locality situated in Kungälv Municipality, Västra Götaland County, Sweden. It had 1,432 inhabitants in 2005. It has held city privileges since 1200. The most striking feature about Marstrand is the 17th century fortress Carlsten, named after King Carl X Gustav of Sweden. The...
,
SwedenSweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
, but it is assumed to have been lost. In 1814, writing for
The Edinburgh Encyclopaedia,
William Elford LeachWilliam Elford Leach FRS was an English zoologist and marine biologist.Leach was born at Hoe Gate, Plymouth, the son of a solicitor. At the age of twelve he went to school in Exeter, studying anatomy and chemistry. By this time he was already collecting marine samples from Plymouth Sound and along...
erected a new genus,
CarcinusCarcinus 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:...
to hold this species alone (making it the
type speciesIn biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of the genus, by monotypy). In 1847, Nardo described a distinct
subspeciesSubspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
occurring in the
Mediterranean SeaThe Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
, which is now recognised as a distinct species,
Carcinus aestuariiCarcinus aestuarii is a littoral crab, native to the Mediterranean Sea. It bears some similarities to Carcinus maenas and was sometimes considered to be a subspecies thereof, rather than a species in its own right, but a molecular biological study using the COI gene found the difference between the...
.
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