Hemigrapsus sanguineus | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Malacostraca |
Order: | Decapoda |
Suborder: | Pleocyemata |
Infraorder: | Brachyura |
Family: | Varunidae |
Genus: | Hemigrapsus |
Species: | H. sanguineus |
Binomial name | |
Hemigrapsus sanguineus | |
Synonyms [1] | |
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Hemigrapsus sanguineus, the Japanese shore crab or Asian shore crab, is a species of crab from East Asia. 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.
H. sanguineus has a squarish carapace, 2 inches (50 mm) in width, with three teeth along the forward sides; its pereiopods are marked with alternating light and dark bands. [2] 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. [3] 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. [4] There currently is no mitigation against these crabs. A natural enemy of H. sanguineus is Sacculina polygenea , [5] a parasite that attacks adult shore crabs and is specific to H. sanguineus. [6]
H. sanguineus is an "opportunistic omnivore" that prefers to eat other animals, especially molluscs, when possible. [7] It tolerates a wide range of salinities (euryhaline) and temperatures (eurythermic). [2]
Females produce up to 50,000 eggs at a time, and can produce 3–4 broods per year. [2] The eggs hatch into zoea larvae, which develop through four further zoea stages, and one megalopa stage, over the course of 16–25 days. [7] 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. [6] The larvae are planktonic, can be transported for long distances during their development into benthic adults. [7]
Typically, the crabs live in areas with large rocks, such as between boulders on rocky shores. [8] Hemigrapsus sanguineus inhabits many artificial structures such as on oyster reefs. [9] H. sanguineus can tolerate other habitats, such as salt marshes. [6]
The invasion of the habitat by the H. sanguineus has been characterized by rapid geographical expansion and widespread displacement of competing crab species. [10] 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. [11] 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. [11] 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.
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. [4] Most of the animals consumed by H. sanguineus are small invertebrates, such as mussels, snails, and amphipods. [6] The diet of these crabs is overall very broad.
The native distribution of H. sanguineus is in coastal waters of the northwestern Pacific Ocean, ranging from Peter the Great Bay in southern Russia, to Hong Kong. [12]
The first record of this crab outside its native range [13] [14] [15] was from Townsends Inlet, Cape May County, New Jersey (between Avalon and Sea Isle City) in 1988. [2] [16] The larvae are thought to have been transported via the fouled hulls of yachts. [8] From the 1990s, it spread as an invasive species through similar vectors such as ballast water and became increasingly common, now ranging from eastern Maine (Great Wass Island) [17] to North Carolina. [8] [13]
In 1999, H. sanguineus was reported for the first time from European waters, having been discovered at Le Havre (France) and the Oosterschelde estuary (in the Netherlands). [18] It has since been found along a long stretch of the continental coast of the English Channel, from the Cotentin Peninsula to the Dover Strait. [19] Its range has extended east and north along the North Sea coastline, including northwestern Germany and Western Jutland of Denmark. [20] [21] In the United Kingdom, it has been recorded from Guernsey and Jersey, and in Kent and south Wales. [22] The species was first reported to be found in Sweden in 2012. [23] 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 in the Skagerrak–Kattegat region. The specimens were very small, suggesting that the crab is now reproducing in Swedish waters. [24] A couple of months later it was first reported from the Øresund, the narrow strait between the Danish Island of Zealand and the Swedish province of Scania. [25] There is a single record of H. sanguineus in the Mediterranean Sea – a 2003 sighting in the northern Adriatic Sea – and a single specimen has been collected from the Romanian coast of the Black Sea, near Constanța, in 2008. [12]
In 2020, positive identification of the species was confirmed within Port Phillip Bay, Victoria, Australia. Since then, there have been many verified sightings and it is now classed as an established species in Victoria, Australia.
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers on each arm. They first appeared during the Jurassic period, around 200 million years ago.
Rhithropanopeus harrisii is a small omnivorous crab native to Atlantic coasts of the Americas, from New Brunswick to Veracruz.
Carcinus maenas is a common littoral crab. It is known by different names around the world. In the British Isles, it is generally referred to as the shore crab, or green shore crab. In North America and South Africa, it bears the name European green crab.
The Jonah crab is a marine brachyuran crab that inhabits waters along the east coast of North America from Newfoundland to Florida. Jonah crabs possess a rounded, rough-edged carapace with small light spots, and robust claws with dark brown-black tips. The maximum reported carapace width for males is 8.7 in (222 mm), while females rarely exceed 5.9 in (150 mm). It is the closest relative to the European brown crab in the Western Atlantic.
Hemigrapsus sexdentatus, also called the “common rock crab” or “common shore crab,” is a marine crab indigenous to the southern shores of New Zealand. This crab is a member of the Varunidae family in the order Decapoda.
Hemigrapsus crenulatus, the hairy-handed crab or papaka huruhuru, is a marine crab of the family Varunidae, endemic to the New Zealand coast, although a taxon in Chile may be conspecific. It is an intertidal species with semi-terrestrial tendencies. They are named by their characteristic setae, or patches of thick hair, on the chelipeds and legs. They can range from green to brown in coloration. Adult crabs are generally 2–4 cm (0.8–1.6 in) wide at the carapace, although the smallest mature crabs can be around just 1 cm (0.4 in) wide. and are able to survive and reproduce in environments of widely varying salinities.
The Smooth Shore Crab is a marine large-eyed crab of the family Grapsidae, found in New Zealand and the Juan Fernández Islands of Chile.
Charybdis is a genus of swimming crabs in the family Portunidae. It is named after the monster Charybdis of Greek mythology.
The Grapsoidea are a superfamily of crabs; they are well known and contain many taxa which are terrestrial (land-living), semiterrestrial, or limnic. Another well-known member with a more conventional lifestyle is the Chinese mitten crab, Eriocheir sinensis.
The Varunidae are a family of thoracotrematan crabs. The delimitation of this family, part of the taxonomically confusing Grapsoidea, is undergoing revision. For a long time, they were placed at the rank of subfamily in the Grapsidae, but they appear to be closest to Macropthalmus and the Mictyridae, which are usually placed in the Ocypodoidea. It may thus be better to merge the latter superfamily with the Grapsoidea, retaining the latter name as it is older.
Hemigrapsus oregonensis is a small shore crab of the family Varunidae; 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, bay shore crab and Oregon shore crab. Despite its common name, the crab actually has a wide variety of coloration. It is found along the West Coast of the United States and Canada, specifically along shorelines and similar geographical areas. In 2009, H. oregonensis was included on a list of animals petitioning for the endangered species label, but there was not enough scientific information available for it to be considered as such, so it remains unevaluated to the present day.
Hemigrapsus takanoi, the brush-clawed shore crab or Asian shore crab, is a small crab of the family Varunidae that lives on rocky shores surrounding the Pacific Ocean, and which is invasive along the European coastlines. This crab is omnivorous and eats small fish, invertebrates and algae.
Helice tridens is a species of crab which lives on mudflats around the coasts of Japan and the Korean Peninsula.
Pachygrapsus marmoratus is a species of crab, sometimes called the marbled rock crab or marbled crab, which lives in the Black Sea, the Mediterranean Sea and parts of the Atlantic Ocean. It is dark violet brown, with yellow marbling, and with a body up to 36 millimetres (1.4 in) long. A semiterrestrial omnivore, it feeds on algae and various animals including mussels and limpets.
Hemigrapsus is a genus of varunid crabs comprising thirteen species native almost exclusively in the Pacific Ocean, but two have been introduced to the North Atlantic region.
Chionoecetes opilio, a species of snow crab, also known as opilio crab or opies, is a predominantly epifaunal crustacean native to shelf depths in the northwest Atlantic Ocean and north Pacific Ocean. It is a well-known commercial species of Chionoecetes, often caught with traps or by trawling. Seven species are in the genus Chionoecetes, all of which bear the name "snow crab". C. opilio is related to C. bairdi, commonly known as the tanner crab, and other crab species found in the cold, northern oceans.
Caprella mutica, commonly known as the Japanese skeleton shrimp, is a species of skeleton shrimp. They are relatively large caprellids, reaching a maximum length of 50 mm (2.0 in). They are sexually dimorphic, with the males usually being much larger than the females. They are characterized by their "hairy" first and second thoracic segments and the rows of spines on their bodies. Body color ranges from green to red to blue, depending on the environment. They are omnivorous highly adaptable opportunistic feeders. In turn, they provide a valuable food source for fish, crabs, and other larger predators. They are usually found in dense colonies attached to submerged man-made structures, floating seaweed, and other organisms.
Hemigrapsus penicillatus is a species of crab. The native range of Hemigrapsus penicillatus extends from the Russian Far East along the coasts of Japan, China, Taiwan and Korea, as far south-west as Hong Kong. Although the species was reported from Hawaii in 1903, this is likely to have been an error; there are no recent records of the species in the central Pacific. Reports of H. penicillatus on the coasts of Europe refer to a related species, H. takanoi, which was only distinguished from H. penicillatus in 2005, several years after its discovery in Europe. Hemigrapsus penicillatus lives in the intertidal zone on stony or muddy shores.
Polyascus is a genus of barnacles in infraclass Rhizocephala. It was circumscribed in 2003 by Henrik Glenner, Jørgen Lützen, and Tohru Takahashi. They included three species, all transferred from Sacculina. The generic name polyascus refers to the typical presence of multiple external sac-like female bodies, known as externae. In Polyascus species, these originate from asexual reproduction.