Eriocheir sinensis
(Chinese mitten crab)

Preferred Common Name

• Chinese mitten crab

International Common Names

• English: big gate crab; big sluiceway crab; Chinese freshwater edible crab; Chinese mitten crab; Chinese mitten crab; Chinese mitten-handed crab; Chinese river crab; crabe chinois; hairy crab; mitten crab; river crab; Shanghai crab; villus crab
• Russian: kitajskij mokhnatorukij krab
• Chinese: pangxie

Local Common Names

• Denmark: kinesiske uldhandskrabbe
• Finland: villasaksirapu
• Germany: Chinesische Wollhandkrabbe; Wollhandkrabbe
• Lithuania: kinijos krabas
• Netherlands: Chinese wolhandkrab
• Poland: krab welnistoreki; kraba welnistoreki
• Sweden: kinesisk ullhandskrabba

• Domain: Eukaryota
•     Kingdom: Metazoa
•         Phylum: Arthropoda
•             Subphylum: Crustacea
•                 Class: Malacostraca
•                     Subclass: Eumalacostraca
•                         Order: Decapoda
•                             Suborder: Reptantia
•                                 Unknown: Grapsidoidea
•                                     Family: Grapsidae
•                                         Genus: Eriocheir
•                                             Species: Eriocheir sinensis

E. sinensis has hairy claws with white tips which make the crab appear to be wearing "mittens" and hence the common name (Gollasch, 2006).

Clark (2006) recently revised the taxonomic classification of R. sinensis moving it from the Grapsidae family to the Varunidae. The taxonomy is often under debate and is believed to include six species (Veilleux and de Lafontaine, 2007).

E. sinensis is named the ‘mitten crab’ because of the dense mat of hair which occurs on the white-tipped chela (claws) of larger juveniles and adults. Claws and chelipeds are equal in size. The shell (carapace) is markedly convex, has four acute spines on either side and a notch between the eyes. It reaches a width of approximately 3 inches (80 mm). The legs of the adult crab are generally more than twice as long as the width of the carapace. The propodus of the last ambulatory legs are narrow and slender, their dactylus sharply claw shaped. Adult crabs are greyish green, light brown orange-brown or dark brown, sometimes with two pale spots on the carapace (ISSG, 2004). Juveniles are frequently lighter coloured than adults. Females have a wide abdominal flap that extends to the edge of the abdomen when fully mature; males have a narrower abdominal flap.

Natural Dispersal

E. sinensis will naturally migrate towards the sea to reproduce. Distances of 1500 km have been reported (Sewell, 2016). Juveniles will also naturally migrate upstream to freshwater.

Accidental Introduction

E. sinensis has been accidentally introduced into new locations in ballast water.

Intention Introduction

E. sinensis has been intentionally introduced into new lcoations for aquarium purposes.

The burrowing activity of crabs, especially large numbers of juveniles, accelerates the erosion of dykes, stream banks and levées in European countries.

E. sinensis have affected commercial and recreational fishing. Crabs caught in the nets can damage the nets and kill netted species. They also are responsible for bait loss and damage to fishing gear. Water intakes were reported to be clogged by mitten crabs during mass developments.

In China, crabs may consume rice shoots.

The burrowing activity of crabs, especially large numbers of juveniles, accelerates the erosion of dykes, stream banks and levées in European countries. Crabs probably damage the aquatic food chain of freshwater and estuarine habitats. During 1998, large numbers of migrating adult crabs disrupted endangered fish salvage operations at water diversion facilities in California, USA. The crabs followed moving water into the facility and clogged the fish holding tanks (ISSG, 2004).

Crabs probably damage the aquatic food chain of freshwater and estuarine habitats. They are omnivorous and non-discriminatory in their diet. They affect other species through competition, overlapping in dietary and habitat preferences. In the UK they may threaten populations of native crayfish (NHM, 2004).

This species is a host for lung fluke (Paragonimus westermani) in Asia. Mammals, including humans are also hosts of this parasite after consuming raw or inadequately cooked crab. Lung fluke has not yet been reported in the crab's European range (Gollasch, 2006).

• Proved invasive outside its native range

• Ecosystem change/ habitat alteration
• Negatively impacts human health
• Negatively impacts livelihoods
• Negatively impacts aquaculture/fisheries
• Threat to/ loss of native species

• Competition - monopolizing resources

In Southeast Asia, E. sinensis is one of the most commercially valuable crabs in East and Southeast Asia (e.g., see Peng, 1986; Zhao et al., 1988; Ng, 1998; Lai and Lu, 1992), where the gonads, which develop during the annual downstream migration, are regarded as a delicacy. Eating the developing mitten crab gonads has been part of Chinese culture for many centuries dating back to the Ming Dynasty (1368-1644), when skilled craftsmen made a set of gold utensils for eating a crab that included a mallet, scissors, a shell cracker, a round salver, scoop, spoon, a long fork and combined scraper and pricker. Today, E. sinensis command a high price in Souteast Asian restaurants (e.g., ca. $40 for a single crab in the right condition) during the autumnal months when they are harvested during their brackish estuarine water and marketed. Typically while in season, E. sinensis can be purchased from street markets as in Hong Kong. However, wild Chinese populations have dramatically declined due to overexploitation, increased demand, river pollution and irrigation schemes that have disrupted the natural migration patterns of this species (Hymanson et al., 1999). But, local and international demands for E. sinensis have been met by an intensive aquaculture programme and this species has been farmed throughout China for the last 40 years (Sui et al., 2009) especially along the Yangtze valley (Jin et al., 2001; Wang et al., 2006). This industry is estimated to be worth ca. US$ 1.25 billion annually.

Mitten crabs have also been a popular subject for beautiful brush-stroke paintings in China. E. sinensis may also be used as bait for fishing.