Aquaculture for all

Invasive Asian Paddle Crab Could Spread Devastating Diseases

Crustaceans Health Sustainability +6 more

AUSTRALIA - If you are crabbing over summer in the West Coast Region, the Department of Fisheries is calling for help from fishers in reporting any unusual crabs they find when fishing in the Swan River, following the discovery of three pest crabs last year.

Lucy Towers thumbnail

The Asian paddle crab (Charybdis japonica) is an aggressive non-native crab that could spread devastating disease to prawns, crabs and lobsters.

It can carry a disease that causes poisoning in humans and could out-compete native crabs like our iconic blue swimmer.

Biosecurity Section Leader Victoria Aitken said the Asian paddle crab was not currently established in Australia, but had significant potential to do so and become a major marine pest.

“Since this time last year, when three of the pest crabs were captured in the Swan River by recreational fishers, extensive trapping, netting, diving and awareness-raising activities have been undertaken with no further Asian paddle crabs found,” she said. “We must remain alert.”

Awareness-raising is set to continue for a while longer to ensure that all pest crabs have been removed. Despite the Department of Fisheries setting over 900 traps in the Swan River in the past 12 months, no Asian paddle crabs have been found.

“If there are any more pest crabs out there, the community will play a vital role in catching them,” Ms Aitken said.

“The Department requests that everyone continue to report anything unusual and keep a careful eye out.”

“We urge fishers to take a good look at any crabs they catch and compare them to the Asian paddle crab pest alert for identification information. If they think they have the pest, retain that crab and contact FISHWATCH on 1800 815 507 before coming ashore, or as soon as possible afterwards, so a Fisheries and Marine Officer can make contact and provide further advice.”

The Asian paddle crab is typically smaller than the blue swimmer crab; adults have a shell width of 120 mm. It has six sharp spines between the eyes, and six spines down each side of the shell. Its colour can vary. The pest alert for this species is available at

Anyone who suspects they have found this, or any other marine or freshwater pest, is asked to call FISHWATCH, or email to, or use the free WA PestWatch app, which can be downloaded from the App Store and Google Play Store.

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