Asian paddle crab

Status in New Zealand

Present in some areas of New Zealand

Legal Status in New Zealand

Under management

Description

The Asian paddle crab is a swimming crab native to South East Asia. It is normally found in the waters of Japan, Korea and Malaysia. It was first detected in New Zealand in 2000 and is presently found in the Waitamata and Whangarei harbours and Waikare Inlet in Northland. It inhabits intertidal to subtidal estuarine habitats and in New Zealand it is found on a number of different substrate types from fine muds to reefs. Adult Asian paddle crabs can produce hundreds of thousands of offspring and it is thought that reproduction is limited to seawater temperatures of over 20°C. Larvae are relatively long-lived and can survive for three to four weeks potentially facilitating spread to new areas. Adults are also capable of swimming large distances. Human activities can assist in the spread of the Asian paddle crab, it likely entered New Zealand associated with vessels either as larvae entrained in ballast water or as hull fouling.

Why is it a problem?

The Asian paddle crab is aggressive and has the potential to compete with native crabs and other benthic species for habitat and food. It may consume shellfish species that are culturally and economically important and may be a nuisance species to water users as it can inflict a vicious bite when disturbed.

What do they look like?

Key Features The Asian paddle crab is a relatively large crab with paddle-like hind legs. Adults have a shell width of around 12cm with six distinct spines or spikes on each side of the eyes.  It ranges in colour from pale green through olive green, to a deep chestnut brown with purplish markings on the carapace (shell).  Most of the crabs found in the Waitemata Harbour tend to have yellow-orange and brown-orange markings on the shell and legs with white tips on the claws. [Image: Chris Woods NIWA]

Download an identification guide

• Asian paddle crab identification guide [1.6 MB]

Find out more about this species

• Global invasive species database
• CABI Invasive species compendium

Related content

• Hard shell mating and response to sex pheromones in the Asian paddle crab

• Trial of a Control Programme for Non-Indigenous Crustaceans using Charybdis japonica as a case study (2008). MPI Technical paper No: 2009/03. 32 p. ISBN 978-0-478-33863-8 [PDF 2.8 MB]

• Brockerhoff, A., McLay, C. (2008). No Frontiers in the Sea for Marine Invaders and their Parasites? MPI Technical paper No: 2008/10. 111 p. ISBN 978-0-478-32177-7 [PDF 1.2 MB]