Carcinus
Encyclopedia
Carcinus is a genus
of crab
s, which includes Carcinus maenas
, an important invasive species
, and C. aestuarii
, a species endemic
to the Mediterranean Sea
.
". It is native to the north-east Atlantic Ocean
and Baltic Sea
, but has colonised similar habitats in Australia, South Africa, South America and both Atlantic and Pacific
coasts of North America. It grows to a carapace
width of 90 millimetres (3.5 in), and feeds on a variety of molluscs
, 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 aquaculture
, and rafting.
C. maenas is known by different names around the world. In the British Isles
, it is generally referred to simply as the shore crab. In North America
and South Africa
, it bears the name green crab or European green crab. In Australia
and New Zealand
, it is referred to as either the European green crab or European shore crab.
. It is very similar to C. maenas, and is sometimes considered to be a subspecies
of C. maenas rather than a species in its own right. The two taxa can be distinguished by the front of the carapace
, between the eyes, which is short and toothed in C. maenas, but longer and smoother in C. aestuarii. Unlike C. maenas, C. aestuarii has only been implicated in one invasion; the coastline of Japan
has been invaded by either C. aestuarii or a hybrid of C. aestuarii and C. maenas.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of crab
Crab
True 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...
s, which includes Carcinus maenas
Carcinus maenas
Carcinus maenas is a common littoral crab, and an important invasive species, listed among the 100 "world's worst alien invasive species". It is native to the north-east Atlantic Ocean and Baltic Sea, but has colonised similar habitats in Australia, South Africa, South America and both Atlantic and...
, an important invasive species
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....
, and C. aestuarii
Carcinus aestuarii
Carcinus 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...
, a species endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to the Mediterranean Sea
Mediterranean Sea
The 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...
.
Carcinus maenas
Carcinus maenas is among the 100 "world's worst alien invasive speciesInvasive 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....
". It is native to the north-east Atlantic Ocean
Atlantic Ocean
The 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 Sea
Baltic Sea
The 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 Pacific
Pacific Ocean
The 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 carapace
Carapace
A 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 molluscs
Mollusca
The 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 aquaculture
Aquaculture
Aquaculture, 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 Isles
British Isles
The 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 America
North America
North 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 Africa
South Africa
The 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 Australia
Australia
Australia , 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 Zealand
New Zealand
New 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.
Carcinus aestuarii
Carcinus aestuarii is a native to the Mediterranean SeaMediterranean Sea
The 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...
. It is very similar to C. maenas, and is sometimes considered to be a subspecies
Subspecies
Subspecies 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...
of C. maenas rather than a species in its own right. The two taxa can be distinguished by the front of the carapace
Carapace
A 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...
, between the eyes, which is short and toothed in C. maenas, but longer and smoother in C. aestuarii. Unlike C. maenas, C. aestuarii has only been implicated in one invasion; the coastline of Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
has been invaded by either C. aestuarii or a hybrid of C. aestuarii and C. maenas.