Hemigrapsus sanguineus (Asian shore crab)
- Summary of Invasiveness
- Taxonomic Tree
- Distribution Table
- History of Introduction and Spread
- Habitat List
- Biology and Ecology
- Latitude/Altitude Ranges
- Air Temperature
- Water Tolerances
- Natural enemies
- Notes on Natural Enemies
- Impact Summary
- Economic Impact
- Environmental Impact
- Risk and Impact Factors
- Similarities to Other Species/Conditions
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Hemigrapsus sanguineus (De Haan, 1853)
Preferred Common Name
- Asian shore crab
International Common Names
- English: Japanese shore crab
Local Common Names
- Japan: isogani
- Netherlands: blaasjeskrab
- USA: Western Indo-Pacific crab
Summary of InvasivenessTop of page
H. sanguineus is a relatively small intertidal shore crab native to cobble/boulder coastlines in the western Pacific Ocean, from Hong Kong Island to Sakhalin Island (China, Japan, Korea, Russia, 22°N to 49° N) (Sakai, 1976). In September 1988, it was found in Townsends Inlet, New Jersey, USA (Williams and McDermott, 1990). Since then it has spread rapidly northward, into eastern Connecticut and Rhode Island in the late 1990s, and all the way to Maine in the early 2000s. There has also been some southerly spread into North Carolina. There have been no reports of this species south of Cape Hatteras (it is absent in South Carolina, Georgia and Florida). H. sanguineus is also found to be invasive in Europe (Dauvin et al., 2009). It is considered invasive because it is able to achieve extremely high densities, with apparent negative impacts on small recruits and juveniles of several native species (barnacles, littorine snails, brachyuran crabs, mytilid bivalves) (Lohrer and Whitlatch, 2002a,b).
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Crustacea
- Class: Malacostraca
- Subclass: Eumalacostraca
- Order: Decapoda
- Suborder: Pleocyemata
- Family: Varunidae
- Genus: Hemigrapsus
- Species: Hemigrapsus sanguineus
DescriptionTop of page
The carapace of H. sanguineus ranges from green through to purple, orange-brown or red. It has shaded bands on its legs and red spots on its claws. A relatively small, square-shelled crab with a carapace width (CW) of 35-40 mm. Distinguishing features include the presence of three spines on each side of the carapace and in males there is a fleshy, bulb-like structure on the claws (USGS, 2002).
DistributionTop of page
Native to cobble/boulder coastlines in the western Pacific Ocean, from Hong Kong Island to Sakhalin Island (China, Japan, Korea, Russia, 22°N to 49° N) (Sakai, 1976), and introduced as an exotic in the USA as a result of ship and boat hull fouling. In Europe, H. sanguineus ranges from the western part of the English Channel to Germany (Dauvin et al., 2009). It was first found in Sweden on the Gothenburg archipelago in 2012 (Berggren, 2013).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Atlantic, Northwest||Widespread||Introduced||1988||Invasive||Lohrer and Whitlatch, 2002a; Lohrer and Whitlatch, 2002b; Lohrer et al., 2000b||Extremely high densities in the late 1990s/ early 2000s in eastern Connecticut and Rhode Island, USA. Long Island Sound.|
|Pacific, Northwest||Widespread||Native||Not invasive||Sakai, 1976||Wide latitudinal range, relatively common and conspicuous shore crab|
|China||Present||Native||Not invasive||Sakai, 1976|
|-Hong Kong||Present||Native||Not invasive||Sakai, 1976; Depledge, 1984|
|Japan||Present||Present based on regional distribution.|
|-Hokkaido||Present||Native||Not invasive||Sakai, 1976; Takahashi et al., 1985|
|-Honshu||Present||Native||Not invasive||Sakai, 1976; Fukui and Wada, 1983; Fukui, 1988|
|-Kyushu||Present||Native||Not invasive||Sakai, 1976; Takada and Kikuchi, 1991|
|-Shikoku||Present||Native||Not invasive||Sakai, 1976|
|Korea, Republic of||Present||Native||Not invasive||Hwang et al., 1993|
|-Connecticut||Present||Introduced||mid-1990s||Invasive||Lohrer and Whitlatch, 2002a; Lohrer and Whitlatch, 2002b; Lohrer et al., 2000b|
|-Delaware||Present||Introduced||late 1980s/early 1990s||Invasive||Epifanio et al., 1998|
|-Massachusetts||Present||Introduced||late 1990s||Invasive||Ledesma and O'Connor, 2001|
|-New Hampshire||Present||Introduced||late 1990s||Invasive||Tyrrell and Harris, 2000|
|-New Jersey||Present||Introduced||late 1980s/early 1990s||Invasive||Williams and McDermott, 1990||First recorded in Townsends Inlet, New Jersey in 1988|
|-Rhode Island||Present||Introduced||mid/late 1990s||Invasive||Lohrer and Whitlatch, 2002a; Lohrer and Whitlatch, 2002b; Lohrer et al., 2000b|
|Belgium||Present||Introduced||Dauvin et al., 2009|
|France||Present||Introduced||Breton et al., 2002|
|Germany||Present||Introduced||Dauvin et al., 2009|
|Netherlands||Present||Introduced||Breton et al., 2002|
|Russian Federation||Present||Present based on regional distribution.|
|-Russian Far East||Present||Native||Not invasive||Sakai, 1976|
|Sweden||Present, few occurrences||Introduced||2012||Berggren, 2013||First occurance 21/07/2012, 57.691735°N 11.635355°E. Five more individuals have been sighted since then along the Gothenburg archipelago.|
History of Introduction and SpreadTop of page
The introduction of H. sanguineus to the USA was apparently accidental, possibly associated with ocean-going vessel traffic. Planktonic life-stages (zoeae and megalopae) may have arrived in ballast water in 1985 or earlier. Small H. sanguineus instars could have gone undetected at first, especially if initial densities were below a reasonable detection limit. In contrast, the transport of adult stages could have occurred as late as 1988 [from Lohrer, 2001].
IntroductionsTop of page
|Introduced to||Introduced from||Year||Reason||Introduced by||Established in wild through||References||Notes|
|Natural reproduction||Continuous restocking|
|USA||Asia||1985-1988||Yes||Williams and McDermott (1990)||Ship/boat hull fouling. Several individuals, including gravid females discovered in 1988|
HabitatTop of page
In New England, H. sanguineus is generally found in rocky intertidal habitats (Lohrer and Whitlach, 2002a). Lohrer (2001) reports that: “Susan Park at University of Delaware finds the crabs on several types of human-constructed structures in this region (rip-rap, jetties, bulkheads, wooden piers, groins, etc.). Apparently, the crabs survive in enclosed harbours as well as on exposed coast. In addition, both intertidal and subtidal oyster reefs support populations of the invasive crabs. To summarize, H. sanguineus colonizes a variety of hard substrates in the southeastern USA despite the absence of intertidal cobble habitats".
See Dauvin et al. (2009) for further information on habitat preferences in Europe.
Habitat ListTop of page
|Coastal areas||Principal habitat|
|Intertidal zone||Principal habitat|
|Salt marshes||Secondary/tolerated habitat|
|Benthic zone||Secondary/tolerated habitat|
Biology and EcologyTop of page
Fully grown H. sanguineus females can likely produce >50,000 eggs at a time (Fukui, 1988; McDermott 1998b). The eggs of H. sanguineus are of intermediate size (0.015 mm3), relative to other co-occurring grapsid crabs in Japan (Fukui, 1988). The eggs hatch into larvae, which proceed to molt through five zoeal stages to become megalopae (Hwang et al., 1993). Megalopae can be found in the water column or on the benthos (Hwang et al., 1993; Lohrer, 2000). After settlement and metamorphosis, the first crab stage is usually between 1.6 and 2.0 mm carapace width (Epifanio et al., 1998; Lohrer, 2000). The time from hatching to first instar undoubtedly varies with latitude, but takes 25+ days under optimal conditions (warm water of high salinity) (Hwang et al., 1993; Epifanio et al., 1998) [from Lohrer, 2001].
Physiology and Phenology
In temperate areas, females first begin to produce eggs in the spring (Takahashi et al., 1985; Fukui, 1988; Lohrer and Whitlatch, 1997; Saigusa and Kawagoye, 1997; Ledesma and O’Connor, 2001). Gravid females release their eggs when water temperatures are warm and larval settlement usually occurs in late summer and fall (Fukui, 1988; Lohrer, 2000). Settled crabs grow rapidly at first, probably molting four or five times in their first month on the benthos (Epifanio et al., 1998). Although winter temperatures likely slow growth considerably, the growth rate of these crabs diminishes after maturity regardless of temperature effects (Fukui, 1988) [from Lohrer, 2001].
There were no explicit investigations of the diet of native H. sanguineus populations until the late 1990s (Lohrer et al., 2000b). Most Japanese researchers assumed that the crab was largely herbivorous. Depledge (1984) observed H. sanguineus grazing algae from rock surfaces, but never performed gut content analyses. In central Japan, H. sanguineus often picks at Caulacanthus okamurai, a red algal turf attached to large cobbles in intertidal areas. However, several small invertebrate species live inside the matrix formed by stout filaments of the alga. It is not known whether the crab incidentally consumes the invertebrates with the alga, or whether it targets animal food items specifically. In any case, as much as 40% of the diet of H. sanguineus is composed of small invertebrates (including mussels, snails, amphipods, and polychaetes).
In North America, several investigators have reported the regular consumption of animal food items by H. sanguineus (Lohrer and Whitlatch, 1997; McDermott, 1999; Lohrer et al., 2000b; Brousseau et al., 2001; Ledesma and O’Connor, 2001). Males of this species have larger claws than females and can consume larger prey items (McDermott, 1999; Brousseau et al., 2001). However, both males and females apparently focus on relatively small prey items (i.e. species with small maximum sizes and/or recruits and juveniles of larger species) (Lohrer et al., 2000b). Although taxonomic differences obviously exist between northeastern Asia and northeastern North America, many of the same types of food items are encountered by H. sanguineus in both regions (e.g. ephemeral green algae, mytilid bivalves, littorinid snails, gammarid amphipods, nereid worms). Several species of intertidal barnacle exist in central Japan, but none were observed inside native H. sangineus guts (Lohrer et al., 2000b). However, in North America, barnacles are regularly found in the guts of wild-caught crabs (Lohrer and Whitlatch, 1997; McDermott 1999; Lohrer et al., 2000b; Ledesma and O’Connor 2001). The barnacles and molluscs that H. sanguineus consumes in eastern North America may have softer shells than their Asian counterparts, and may be more susceptible to predation by invasive shore crabs (Lohrer et al., 2000b) [from Lohrer, 2001].
Latitude/Altitude RangesTop of page
|Latitude North (°N)||Latitude South (°S)||Altitude Lower (m)||Altitude Upper (m)|
Air TemperatureTop of page
|Parameter||Lower limit||Upper limit|
|Mean maximum temperature of hottest month (ºC)||0||30|
|Mean minimum temperature of coldest month (ºC)||-10||0|
Water TolerancesTop of page
|Parameter||Minimum Value||Maximum Value||Typical Value||Status||Life Stage||Notes|
|Salinity (part per thousand)||33||35||Optimum||25-35 tolerated. Larval tolerances differ to those of adults|
|Turbidity (JTU turbidity)||Optimum||Does not live in really muddy places|
|Water temperature (ºC temperature)||Optimum||5-30 tolerated|
Natural enemiesTop of page
Notes on Natural EnemiesTop of page
In Asia, a rhizocephalan parasite (Sacculina polygenea) attacks H. sanguineus and prevalence can be as high as 80% in some locations (Yamaguchi and Aratake, 1997).
Impact SummaryTop of page
Economic ImpactTop of page
The apparent replacement of Carcinus maenas [European green crab] by H. sanguineus has ecological and economic implications. Although both crabs are non-indigenous, green crabs are pests that impact shellfish resources throughout New England. Green crabs consume more animal matter than H. sanguineus (Elner, 1981; Ropes, 1989; Lohrer and Whitlatch, 1997; Lohrer et al., 2000b) and present a significant selective pressure on a variety of snails, clams, and mussels (Vermeij, 1982a,b; Leonard et al., 1999; Trussell and Smith, 2000; Smith and Jennings, 2000; Whitlow and Dochtermann, 2001). On a per capita basis, green crabs consume more juvenile blue mussels (Mytilus edulis) than H. sanguineus (Lohrer and Whitlatch, 2002b). However, since the densities of H. sanguineus are often 60-80 times greater than those of C. maenas, the collective effects of H. sanguineus are now more important to juvenile blue mussels in rocky intertidal habitats. The invasion by H. sanguineus probably represents a net negative influence on blue mussel populations in the rocky intertidal zone, despite the fact that C. maenas (a more voracious predator) is relatively rare in this habitat type now [from Lohrer, 2001].
Environmental ImpactTop of page
Impact on Biodiversity
Lohrer and Whitlach (2002a) examined the relationship between the European green crab (Carcinus maenas) and H. sanguineus in New England over a 4-year period. During the study, a sharp decline in C. maenas was observed that coincided with an increase in H. sanguineus populations. Lohrer and Whitlach (2002b) reported that in less than 10 years after its appearance in Long Island Sound, H. sanguineus had become the numerically dominant species over C. maenas.
Risk and Impact FactorsTop of page Invasiveness
- Proved invasive outside its native range
- Has a broad native range
- Abundant in its native range
- Highly adaptable to different environments
- Capable of securing and ingesting a wide range of food
- Highly mobile locally
- Long lived
- Fast growing
- Has high reproductive potential
- Altered trophic level
- Ecosystem change/ habitat alteration
- Modification of natural benthic communities
- Monoculture formation
- Reduced native biodiversity
- Threat to/ loss of native species
- Competition - monopolizing resources
- Interaction with other invasive species
- Highly likely to be transported internationally accidentally
- Difficult/costly to control
Similarities to Other Species/ConditionsTop of page
Hemigrapsus is a common genus present in many coastal areas all over the world. Crabs most similar to H. sanguineus include Hemigrapsus penicillatus (which some have said might be a new species called Hemigrapsus takanoi, see Asakura et al. (2005) for further details). The differences between H. sanguineus and H. penicillatus are described by Breton et al. (2002).
ReferencesTop of page
Asakura A; Watanabe S, 2005. Hemigrapsus takanoi, a new species, a sibling species of the common Japanese intertidal crab H. penicillatus (Decapoda: Brachyura: Grapsidae). Journal of Crustacean Biology, 25(2):279-292.
Berggren; Matz S, 2013. New discoveries of crustaceans on the Swedish west coast. (Nya fynd av kräftdjur vid den svenska västkusten.) Fauna & Flora, 108(3):42-44.
Brousseau DJ; Filipowicz A; Baglivo; JA, 2001. Laboratory investigations of the effects of predator and size on prey selection by the Asian crab, Hemigrapsus sanguineus. Journal of Experimental Marine Biology and Ecology, 262:199-210.
Brousseau DJ; Korchari PG; Pflug C, 2000. Food preference studies of the Asiatic shore crab (Hemigrapsus sanguineus) from western Long Island Sound. In: Marine Bioinvasions: Proceedings of the First National Conference, Cambridge, MA, 24-27 January 1999 [ed. by Pederson J] Cambridge, MA, USA: MIT Sea Grant College Program, 200-207.
Dauvin JC; Rius AT; Ruellet T, 2009. Recent expansion of two invasive crabs species Hemigrapsus sanguineus (de Haan, 1835) and H. takanoi Asakura and Watanabe 2005 along the Opal Coast, France. Aquatic Invasions, 4(3):451-465. http://www.aquaticinvasions.ru/2009/AI_2009_4_3_Dauvin_etal.pdf
Epifanio CE; Dittel AI; Park S; Schwalm S; Fouts A, 1998. Early life history of Hemigrapsus sanguineus, a non-indigenous crab in the Middle Atlantic Bight. Marine Ecology Progress Series, 170:231-238.
Fukui Y, 1988. Comparative studies on the life history of the grapsid crabs (Crustacea, Brachyura) inhabiting intertidal cobble and boulder shores. Publication of the Seto Marine Biological Laboratory, 33((4/6)):121-162.
Lohrer AM; Fukui Y; Wada K; Whitlatch RB, 2000. Structural complexity and vertical zonation of intertidal crabs, with focus on the habitat requirements of the invasive Asian shore crab, Hemigrapsus sanguineus (de Haan). Journal of Experimental Marine Biology and Ecology, 244:203-217.
Lohrer AM; Whitlatch RB, 1997. Ecological studies on the recently introduced Japanese shore crab (Hemigrapsus sanguineus), in eastern Long Island Sound. In: Proceedings of the Second Northeast Conference on Nonindigenous Aquatic Nuisance Species, Burlington, VT, 18-19 April 1997 [ed. by Balcom N] Groton, Connecticut, USA: Connecticut Sea Grant College Program, 49-60.
Lohrer AM; Whitlatch RB; Wada K; Fukui Y, 2000. Using niche theory to understand invasion success: a case study of the Asian shore crab, Hemigrapsus sanguineus. In: Marine Bioinvasions: Proceedings of the First National Conference, Cambridge, MA, 24-27 January 1999 [ed. by Pederson J] Cambridge, MA, USA: MIT Sea Grant College Program, 57-60.
McDermott JJ, 1998. The western Pacific brachyuran Hemigrapsus sanguineus (Grapsidae) in its new habitat along the Altlantic coast of the Untied States: reproduction. Journal of Crustacean Biology, 55(2):289-298.
McDermott JJ, 1998. The western Pacific brachyuran Hemigrapsus sanguineus (Grapsidae), in its new habitat along the Altlantic coast of the Untied States: geographic distribution and ecology. ICES Journal of Marine Science, 55(2):289-298.
McDermott JJ, 1999. The western Pacific brachyuran Hemigrapsus sanguineus (Grapsidae) in its new habitat along the Atlantic coast of the United States: feeding, cheliped morphology and growth. In: Crustaceans and the biodiversity crisis. Proceedings of the Fourth International Crustacean Congress, Amsterdam, the Netherlands, 20-24 July 1998 [ed. by Schram F, von Vaupel Klein J] Brill, Leiden, The Netherlands, 425-444.
Saigusa M; Kawagoye O, 1997. Circatidal rhythm of an intertidal crab, Hemigrapsus sanguineus: synchrony with unequal tide height and involvement of a light response mechanism. Marine Biology, 129:87-96.
Trussell GC; Smith LD, 2000. Induced defenses in response to an invading crab predator: an explanation of historical and geographic phenotypic change. Proceedings of the National Academy of Sciences, 97:2123-2127.
Tyrrell MC; Harris LG, 2000. Potential impact of the introduced Asian shore crab, Hemigrapsus sanguineus, in Northern New England: diet, feeding preferences, and overlap with the green crab, Carcinus maenas. In: Marine Bioinvasions: Proceedings of the First National Conference, Cambridge, MA, 24-27 January 1999 [ed. by Pederson J] Cambridge, MA, USA: MIT Sea Grant College Program, 208-220.
Whitlow L; Dochtermann J, 2001. Phenotypic plasticity of native soft-shell clams in response to chemical and physical stimuli from invasive green crab predation. In: International Conference on Marine Bioinvasions, New Orleans, LA, 9-11 April 2001.
Williams AB; McDermott JJ, 1990. An eastern United States record for the Western Indo-Pacific crab, Hemigrapsus sanguineus (Crustacea: Decapoda: Grapsidae). Proceedings of the Biological Society of Washington, 103(1):108-109.
ContributorsTop of page
23/06/08 Original text by:
Andrew Lohrer, NIWA, Gate 10 Silverdale Road, Hamilton, 3216, New Zealand
Distribution MapsTop of page
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