Description: A fairly large crab which can reach a carapace size of 8 cm. The carapace is roughly square in shape with four teeth on each side. Colouration can vary from green-brown to orange-brown. Pincers have a dense mat of fur on each claw, often referred to as hairy ‘mittens’ which gives the common name ‘Chinese mitten crab.’ Walking legs are relatively long when compared to body size, and covered in hair.

Habitat: Only juveniles of this species are found in the marine environment. Adults move up estuaries, inhabiting both brackish and freshwater, and burrow into muddy riverbanks. Females reported to potentially overwinter in marine environment.

Distribution: Currently there are no records from the island of Ireland aside from a few records from County Wexford. There are numerous records from Britain, especially in south and south east.

Similar Species: Unlikely to be confused with any other species due to distinctive ‘mittens.’ Most similar in appearance to Carcinus maenas but this lacks the dense mats of fur, and there are other differences including carapace shape and colouration.

Key Identification Features:

• Diagnostic dense mats of fur on each claw (mittens).
• Large crab with relatively long legs, covered in hair.
• Roughly square-shaped carapace with four teeth on each side.

Distribution Map from NBN: Eriocheir sinensis at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Eriocheir sinensis at iNaturalist World Species Observations database.

GBIF data for Eriocheir sinensis

WoRMS: Eriocheir sinensis at World Register of Marine Species. Accepted name: Eriocheir sinensis H. Milne Edwards, 1853. AphiaID: 107451.

Classification: Biota; Animalia; Arthropoda; Crustacea; Multicrustacea; Malacostraca; Eumalacostraca; Eucarida; Decapoda; Pleocyemata; Brachyura; Eubrachyura; Thoracotremata; Grapsoidea; Varunidae; Varuninae; Eriocheir