HOME

TheInfoList



OR:

''Hemigrapsus sanguineus'', the Japanese shore crab or Asian shore crab, is a species of crab from
East Asia East Asia is the eastern region of Asia, which is defined in both Geography, geographical and culture, ethno-cultural terms. The modern State (polity), states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. ...
. It has been introduced to several other regions, and is now an invasive species in North America and Europe. It was introduced to these regions by ships from Asia emptying their ballast tanks in coastal waters.


Description

''H. sanguineus'' has a squarish carapace, in width, with three teeth along the forward sides; its pereiopods are marked with alternating light and dark bands. The males have a bulb-like structure at the base of the movable finger on their claws. Other distinguishing features include three spines on each side of the carapace. Adult sizes range from 35–42 mm width. These crabs are opportunistic omnivores that tend to favor other animals over algae. As crab density in an invaded area increases, so does the breadth of the species' diet, which suggests that competition alters selection of food. There currently is no mitigation against these crabs. A natural enemy of ''H. sanguineus'' is ''
Sacculina ''Sacculina'' is a genus of barnacles that is a parasitic castrator of crabs. They belong to a group called ''Rhizocephala''. The adults bear no resemblance to the barnacles that cover ships and piers; they are recognised as barnacles because t ...
polygenea'', a parasite that attacks adult shore crabs and is specific to ''H. sanguineus''.


Ecology and life cycle

''H. sanguineus'' is an "opportunistic omnivore" that prefers to eat other animals, especially
molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...
, when possible. It tolerates 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 ...
( euryhaline) and temperatures (
eurythermic A eurytherm is an organism, often an endotherm, that can function at a wide range of ambient temperatures. To be considered a eurytherm, all stages of an organism's life cycle must be considered, including juvenile and larval stages. These wide ...
). Females produce up to 50,000
eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
at a time, and can produce 3–4 broods per year. The eggs hatch into zoea larvae, which develop through four further zoea stages, and one
megalopa Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow. The ...
stage, over the course of 16–25 days. The eggs typically hatch in late summer or fall, into larvae, and the juvenile crabs molt in five stages to become megalopae, which typically takes about a month. Once in this stage, the crabs settle and metamorphize into full-grown crabs. The larvae are
plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...
ic, can be transported for long distances during their development into benthic adults.


Habitat

Typically, the crabs live in areas with large rocks, such as between boulders on rocky shores. ''Hemigrapsus sanguineus'' inhabits many artificial structures such as on oyster reefs. H. sanguineus can tolerate other habitats, such as salt marshes.


Ecological impacts

The invasion of the habitat by the ''H. sanguineus'' has been characterized by rapid geographical expansion and widespread displacement of competing crab species. Although this species has been introduced to such a large habitat, ''H. sanguineus'' is eaten by native crustacean-eating fish in these areas. Since the crabs are so abundant, some types of native fish even prefer the invading crab. This may be due to the mouths of fish adapting to the size of ''H. sanguineus'' because they are the most abundant food source. On the other hand, native crabs also have adapted to eat ''H. sanguineus'', possibly due to the availability of the food source or as an anti-predator strategy. There is a possibility that ''H. sanguineus'' could expand in numbers in some areas where it is invasive, potentially overwhelming the habitat and out-competing native crustaceans, such as the blue crab and lobster.


Diet

Because the crabs are opportunistic omnivores, they will eat anything they can get their mouths around. ''H. sanguineus'' prefers to consume animals, but during a period of starvation, these crabs tend not to show a food preference. Most of the animals consumed by ''H. sanguineus'' are small invertebrates, such as mussels, snails, and amphipods. The diet of these crabs is overall very broad.


Distribution

The native distribution of ''H. sanguineus'' is in coastal waters of the northwestern Pacific Ocean, ranging from Peter the Great Bay in southern
Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
, to
Hong Kong Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China (abbr. Hong Kong SAR or HKSAR), is a city and special administrative region of China on the eastern Pearl River Delta i ...
.


Introduced distribution

The first record of this crab outside its native range was from Townsends Inlet,
Cape May County Cape May County is the southernmost county in the U.S. state of New Jersey. Much of the county is located on Cape May bound by Delaware Bay to its west and the Atlantic Ocean to its south and east. Adjacent to the Atlantic coastline are f ...
,
New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...
(between
Avalon Avalon (; la, Insula Avallonis; cy, Ynys Afallon, Ynys Afallach; kw, Enys Avalow; literally meaning "the isle of fruit r appletrees"; also written ''Avallon'' or ''Avilion'' among various other spellings) is a mythical island featured in the ...
and
Sea Isle City Sea Isle City is a city in Cape May County, in the U.S. state of New Jersey. It is part of the Ocean City metropolitan statistical area. As of the 2020 United States census, the city's year-round population was 2,104, a decrease of 10 (−0.5 ...
) in 1988. The larvae are thought to have been transported in the ballast water of yachts and cargo ships. From the 1990s, it spread as an invasive species and become increasingly common, now ranging from eastern
Maine 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 ...
( Great Wass Island) to
North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and ...
. In 1999, ''H. sanguineus'' was reported for the first time from European waters, having been discovered at
Le Havre Le Havre (, ; nrf, Lé Hâvre ) is a port city in the Seine-Maritime department in the Normandy region of northern France. It is situated on the right bank of the estuary of the river Seine on the Channel southwest of the Pays de Caux, very ...
(France) and the
Oosterschelde The Eastern Scheldt ( nl, Oosterschelde) is a former estuary in the province of Zeeland, Netherlands, between Schouwen-Duiveland and Tholen on the north and Noord-Beveland and Zuid-Beveland on the south. It also features the largest natio ...
estuary (in the Netherlands). It has since been found along a long stretch of the continental coast of the
English Channel The English Channel, "The Sleeve"; nrf, la Maunche, "The Sleeve" (Cotentinais) or ( Jèrriais), (Guernésiais), "The Channel"; br, Mor Breizh, "Sea of Brittany"; cy, Môr Udd, "Lord's Sea"; kw, Mor Bretannek, "British Sea"; nl, Het Kana ...
, from the
Cotentin Peninsula The Cotentin Peninsula (, ; nrf, Cotentîn ), also known as the Cherbourg Peninsula, is a peninsula in Normandy that forms part of the northwest coast of France. It extends north-westward into the English Channel, towards Great Britain. To its w ...
to the
Dover Strait The Strait of Dover or Dover Strait (french: Pas de Calais - ''Strait of Calais''), is the strait at the narrowest part of the English Channel, marking the boundary between the Channel and the North Sea, separating Great Britain from continent ...
. Its range has extended east and north along the
North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...
coastline, including northwestern Germany and Western
Jutland Jutland ( da, Jylland ; german: Jütland ; ang, Ēota land ), known anciently as the Cimbric or Cimbrian Peninsula ( la, Cimbricus Chersonesus; da, den Kimbriske Halvø, links=no or ; german: Kimbrische Halbinsel, links=no), is a peninsula of ...
of
Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , establish ...
. In the United Kingdom, it has been recorded from Guernsey and
Jersey Jersey ( , ; nrf, Jèrri, label= Jèrriais ), officially the Bailiwick of Jersey (french: Bailliage de Jersey, links=no; Jèrriais: ), is an island country and self-governing Crown Dependency near the coast of north-west France. It is the l ...
, and in
Kent Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...
and south Wales. The species was first reported to be found in Sweden in 2012.''Invasive crab found once more in Swedish waters''
Radio Sweden, 2015-08-07
In 2019, Swedish authorities reported that a private person collected more than 50 specimens of the crab in the vicinity of the island of
Orust Orust () is an island in western Sweden, and Sweden's third largest island. In 2014 Statistics Sweden declared it to instead be the fourth largest island, under a definition which adds artificial canals to the possible bodies of water surrounding ...
in the
Skagerrak The Skagerrak (, , ) is a strait running between the Jutland peninsula of Denmark, the southeast coast of Norway and the west coast of Sweden, connecting the North Sea and the Kattegat sea area through the Danish Straits to the Baltic Sea. T ...
Kattegat The Kattegat (; sv, Kattegatt ) is a sea area bounded by the Jutlandic peninsula in the west, the Danish Straits islands of Denmark and the Baltic Sea to the south and the provinces of Bohuslän, Västergötland, Halland and Skåne in Sweden ...
region. The specimens were very small, suggesting that the crab is now reproducing in Swedish waters.''Nytt fynd av blåskrabba nära Orust''
Länsstyrelsen Västra Götaland, 2019-07-18, Swedish only
A couple of months later it was first reported from the
Øresund Øresund or Öresund (, ; da, Øresund ; sv, Öresund ), commonly known in English as the Sound, is a strait which forms the Danish–Swedish border, separating Zealand (Denmark) from Scania (Sweden). The strait has a length of ; its width ...
, the narrow strait between the Danish Island of
Zealand Zealand ( da, Sjælland ) at 7,031 km2 is the largest and most populous island in Denmark proper (thus excluding Greenland and Disko Island, which are larger in size). Zealand had a population of 2,319,705 on 1 January 2020. It is the 1 ...
and the Swedish province of
Scania Scania, also known by its native name of Skåne (, ), is the southernmost of the historical provinces (''landskap'') of Sweden. Located in the south tip of the geographical region of Götaland, the province is roughly conterminous with Skåne ...
. There is a single record of ''H. sanguineus'' 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 ...
– a 2003 sighting in the northern
Adriatic Sea The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Sea) to t ...
– and a single specimen has been collected from the
Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, and ...
n coast of the
Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Rom ...
, near Constanța, in 2008.


References


External links


Species Profile – Asian shore crab (''Hemigrapsus sanguineus'')
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 ...
{{Taxonbar, from=Q728318 Grapsoidea Crustaceans of the Pacific Ocean Crustaceans described in 1853 Taxa named by Wilhem de Haan