Scientific confirmation this week that a crab, caught recently in Matilda Bay, is an Asian paddle
crab (Charybdis japonica) has prompted a fresh reminder for fishers to be on the lookout for the
An alert fisher, who caught the crab in a drop net on the Swan River late last month, helpfully
reported his find through FISHWATCH.
Senior Biosecurity Management Officer with the Department of Fisheries, Marion Massam today
called on other crab fishers to also continue their vigilance, in the ongoing efforts required to
prevent the pest species from establishing itself in WA.
“Their assistance is crucial – the three paddle crabs previously detected at Mosman Bay in 2012
were all caught by recreational fishers,” Ms Massam said.
“This particular Asian paddle crab was light tan, but we know the species varies greatly in colour
– its definitive features are the sharp spines between the eyes and the six spines down each side, as
identified in the department’s pest alert, which is available at www.fish.wa.gov.au/biosecurity.
“The biosecurity alert also shows pictures of native crabs (particularly the small four-lobed
swimming crab) that have sometimes been confused with the Asian paddle crab.
“The native small, brownish swimming crab has no spines between the eyes – take a close look. If
there are no spines then it’s the native crab.”
In general, fishers should first look at any small crabs with a shell width up to 120 mm that look
different to blue swimmers and then check for the spines between the eyes. Ms Massam said
people should not eat the pest crab, because the species can carry a disease that could cause
poisoning in humans.
“We need to make sure the Asian paddle crab doesn’t establish in Western Australia, as it could
out-compete native species like the blue swimmer, could spread diseases to other crabs and
prawns and would probably be impossible to eradicate,” she said.
“Crab fishers are urged to check their catches and, if in doubt; take photographs, retain suspect
crabs, note the fishing location and contact FISHWATCH on 1800 815 507.”
Aquatic pests and diseases are a significant threat to WA’s precious oceans and rivers. The
Department of Fisheries is leading the effort to prevent them arriving and establishing themselves
in our waters.