Pest species of crab found in SA waters

An Asian Paddle Crab, a pest species that would pose a risk to our Blue Swimmer Crabs if established, has been found in South Australian waters – the fourth detection since 2019.

The crab, a male (pictured), was identified after being caught by fisher on the North Arm Jetty at Port Adelaide last week.

Minister for Primary Industries and Regional Development David Basham highlighted the dangers Asian Paddle Crab present to South Australia.

“It is important that we keep the Asian Paddle Crab out of South Australia, not only due to the high potential this pest could outcompeting native species such as Blue Swimmer Crab but also as they can be a pathway towards introducing exotic disease into our waters,” Minister Basham said.

“I urge all fishers – along with other boat and water users – to keep an eye out and report any suspicious aquatic pests, including the Asian Paddle Crab, while fishing or out in the water.

“By working together we can help keep our native species safe from these exotic invaders. Anyone catching an Asian Paddle Crab should not return it to the water.

“They should retain it separately from any Blue Swimmer Crabs they may have caught, take a photo and immediately report the find to PIRSA via Fishwatch on 1800 065 522.”

The fisher who caught the crab, a deckhand from a prawn boat, recognised it as a pest and handed it over to fisheries officers. It was subsequently provided to the SA Museum for their records.

“I thank this prudent fisher for doing the right thing and raising the alarm which means we were able to identify the crab quickly,” Minister Basham said.

The four crabs found to date, have all been male and experts believe it is unlikely a spawning population exists in Port Adelaide.

A native species in central and eastern Asia, Asian Paddle Crabs are aggressive and could out-compete native crabs like the Blue Swimmer Crab if they became established.

There are also concerns that any exotic crab can spread disease such as white spot, to our local prawns, crabs and lobsters.

How to identify an Asian Paddle Crab:

  • Six spines down each side of the shell
  • Must have paddles on the rear legs (male and female) or it is not an Asian Paddle Crab
  • It can grow to 12cm wide, making it smaller than the Blue Swimmer Crab
  • Found in a number of colours – pale, olive green, brown and purple
  • Sharp spines between its eyes.

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