Chonda crabs in the swan??

 Hi guys and gals,

 

A mate was mentioning today that there are a number of intoruduced Chinese crabs that are entering our swan river. And as a result 2 they are depleting stocks of our beloved blue swimmer crabs?

 

apparently they have come about from Chinese ships emptying their central ballast water just prior to entering freo harbour so they can get the depth clearance to enter the harbour ect. Don't get me wrong I know that the economy nowadays is a worldwide inclusion but this can't be good for our local waterways!!

Scano

P.s chonda = Chinese Honda. Hahah

____________________________________________________________________________

 

 


scano's picture

Posts: 1141

Date Joined: 31/05/07

And for the record

Sun, 2012-12-16 20:19

 By no means is this any form of a racist or racism post.

purely a question that relates to our beloved swan river crabs.

just wanted to make sure that was clear

 

scano

____________________________________________________________________________

 

 

Posts: 130

Date Joined: 03/06/09

That's not quite right

Sun, 2012-12-16 20:55

Australia has Ballast water Regs that require ships to change their ballast water prior to arriving in Australia. Don't go blaming the introduction of these crabs on Chinese alone. Just take a look at the ships in the Harbour - which ones come from China? Not many, in fact hardly any. In contrast, have a look how many Chinese ships berth at Alcoa. If there were that many Chinese crabs surviving then they'd be all around the Alcoa berth and in the Sound.

Don't get me wrong, infestations do occur from ship's ballast water. That's why Australia has introduced these regs but the internatiomnal ships have been coming here for centuries and we've only had these regs for the past 10-15 years.

The ships don't empty their ballast to get into the harbour. They empty it to replace it with cargo. Once again, container ships would exchnage very little ballast water whereas the bulk carriers at Alcoa and Grain Jetty would empty all their ballast here.

Hope I've set the record straight. If you do find any of these Chinese crabs the Fisheries would be very interested in specimens.

Posts: 2303

Date Joined: 03/05/06

This?

Sun, 2012-12-16 23:14

Pest crab warning after Swan River discovery

The Department of Fisheries WA is calling for fishers help in reporting any unusual crabs they find when fishing in the Swan River, following the discovery of an Asian paddle crab – a highly invasive marine pest.

A single specimen of the non-endemic pest species Charybdis japonica has been positively identified, after it was captured by a recreational fisherman at Mosman Bay.

Biosecurity Section Leader Victoria Aitken said several follow-up surveys of the local waters, where the pest crab was found, had not located any further specimens, although public help was now critical in reporting any further possible specimens

“Anyone who suspects they have found this species is asked to call our FISHWATCH reporting line on 1800 815 507 or email biosecurity@fish.wa.gov.au,” Ms Aitken said.

This Asian paddle crab is of particular concern and a biosecurity risk because;

  • It can carry a crustacean virus that could potentially harm native prawns, crabs and lobsters. This nationally notifiable disease has not been found to date in Australian wild populations.
  • These crabs are highly aggressive, and predate on food sources used by native crab species (including blue swimmer crabs), with the potential to outcompete them.

Ms Aitken also recommended that this species of crabs not be eaten, as there had been some cases overseas of people becoming ill.

“Like any aquatic pest, once established it is essentially impossible to eradicate,” she said.

“Since the Asian paddle crab was first detected in New Zealand, in 2000, it has become widespread in parts of the North Island. This is why we are treating this situation very seriously, in order to prevent the same thing happening here.”

Fishers are urged to take a look at any small crabs they catch and, if they think they have caught the pest, they should retain that crab and contact FishWatch on 1800 815 507, prior to 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 smaller than the blue swimmer crab; adults have a shell width of 120 millimetres, it has six distinct sharp spines each side of its eyes, with spines also between the eyes. Its colour can vary. A fact sheet is available online at www.fish.wa.gov.au.

scano's picture

Posts: 1141

Date Joined: 31/05/07

Good info

Mon, 2012-12-17 06:41

 Cheers for the info guys. That clears things up nicely.

Let's hope that the discovery of one in the swan was a bit of a once off.

 

____________________________________________________________________________

 

 

Brody's picture

Posts: 970

Date Joined: 06/02/07

 Hey Scano, that photo is of

Mon, 2012-12-17 11:36

 Hey Scano, that photo is of the big one I caught and handed in to Fisheries. Have caught porobably 7 or 8 (maybe more) over the last 4 or 5 years, and on that particular day we caught 3, all around the Mosman Bay/Blackwall Reach area. Always released them thinking they were baby mud crabs!

Pete D's picture

Posts: 1681

Date Joined: 07/06/07

Native crab very Similiar

Mon, 2012-12-17 12:51

I did a night dive a month ago to look for these crabs...fark, they are everywhere I thought!  Wrong, the native crab looks the same, except it does not have the spikes between the eyes.  Didn't find any, but always looking on each dive now.

Cheers Pete

Adam Gallash's picture

Posts: 15106

Date Joined: 29/11/05

Question

Mon, 2012-12-17 14:49

Question is, what do the paddle crabs taste like?

____________________________________________________________________________

Site Admin - Just ask if you need assistance

Brody's picture

Posts: 970

Date Joined: 06/02/07

Answer: not great.

Tue, 2012-12-18 18:00

Answer: not great.

Posts: 43

Date Joined: 22/11/12

If you've tried them you

Wed, 2012-12-19 15:58

If you've tried them you would know they taste almost exactly the same as the blue swimmers..

Brody's picture

Posts: 970

Date Joined: 06/02/07

The one I had was shit

Wed, 2012-12-19 19:29

The one I had was shit compared to a Blue Swimmer. 

chookc's picture

Posts: 442

Date Joined: 07/01/10

I thought I read somewhere

Tue, 2012-12-25 17:44

I thought I read somewhere that they were poisonous or had a high risk of being very bad for your health. migt have been wrong though