Backyard Aquaponics
A place to discuss aquaponics

I've been thinking about having a play with some yabbies in my system. Eventually I want to do red claw - because they are bigger than cherax destructor, but at first I may have a play with cherax destructor, because I have these very readilly available (in the gully that runs through my place).

This gully is often virtually dry, but has had water in it for the last couple of months because of all the rain. Figured the yabbs will have come back from their long hybernation in the dry, so today chucked a couple of opera house traps in the water hole and also a finer meshed fish trap. Ended up with quite a few yabbs in the finer mesh trap - they are so small they were falling through the opera house pots before I got them through the grass and weeds at the side of the gully.

I pulled about 10 out of the fine meshed trap - this was after it just being in the water for 2 hours. They are small - ranging from about 10mm to 30mm. It must be breeding season, or perhaps breeding is just spurred on by the wet.

I've chucked a few in a small aquarium while I decide whether to proceed. I'll need to set one of my spare fingerling tanks up with a biofilter and escape proof it somehow if I want to proceed.

Do you all reckon it is worthwhile - or just too much trouble.

BTW - I have left the traps in. The intention is/was to catch a few mature ones with the few to cleaning them up of any external parasites etc with some salt baths and then having a go at breeding them and raising the young. See if I can nab a couple of the mummy and daddy ones

Go for it - take one for the team

Hey VB, I say go for it too mate, they are hardy and very easy to breed (as has been mentioned in the thread) it just depends on water temperature. I'm pretty sure they can breed up to 3 times per season given the right conditions and they reach breeding age very quickly. When you do find a berried female, whack her into a separate tank if you have one, then when they hatch put Mum back to get knocked up again and let the littlies grow up a little before putting them in with the big guys.

Sexing them is really easy too, refer to this for a guide... http://www.nswaqua.com.au/InfoLinks/Yabby2.htm, theres lots more useful information on the page too. Their recommendation is to stock 3-4 yabbies per square metre of floor space and definitely no more than 10. I'm going to have to harvest some of my big guys in my system because ive got about 30 in an IBC, and despite having plenty of hides I frequently see partially eaten yabbies on the bottom of the tank and a lot of others that have lost limbs due to fighting.

As for disease/parasites, temnocephala (flatworms) and epistylis are the main thing you will come across when farming them or if water quality is bad, but I'd be surprised if the ones you catch had any such problems. Heres another link on diseases... http://www.fish.wa.gov.au/docs/pub/FHEpistylisTemnocephia/index.php?0408
Have fun and good luck catching some bigger ones, i'd love to see some pics of your catch.

No pics yet - sorry, will try to take some tomorrow.

I forgot all about the pots in the rush to get to work this morning, but remembered just before so went down to the gully in the pitch black and pooring rain. Fine net trap got caught in the vetiver grass that I have planted at the side of the gully to stop the banks from eroding. Managed to pull the opera house pots through though and salvaged 9 yabbs from them. There was a tenth at one point, but only a head left (there used to be a couple of eels in the gully before it dried up altogether, so maybe they are back??).

A couple are very small, but a couple are a bit bigger - but still small. The biggest 2 were about 10cm from tail to head. The biggest ones had the little crawling parasites on them - so have chucked them all into the little aquarium, but will salt bath them at some point. Now have about 20 yabbs in no more than 10 or 15 littres of water sitting in the bottom of a 50 litre aquarium. Have an airstone in there, but no filtration. Will attend to it when I get a chance.

Thats the sort of dedication I've come to expect from my fellow aquaponians

I've put a trap into my IBC tonight to catch me some dinner for tomorrow (don't have a scoop net long enough), hopefully I'll land a couple of the biggies.

I'll put my money on the parasites being temno, if/when you do get a pic I might be able to clarify that for you.

Nice work!

I expect you are right simmo. No pics - can't find the cam . Pulled 5 more out this morning. One of them was a little bigger than the previous biggest. I'll have to look at that sexing guide.

males have raised uo little round nodules on the bit of the leg joining the body on their legs closest to the tail. Females have flatter round nodules on about the 3rd pair of legs up from the tail right where they attach to the body. (hope that ,makes sense) Some yabbies seem to have both. (WTF)

Seems that the destructor are pretty salt tolerant. Gave them a bath in a very high concentration of salt today. The small ones I left in for maybe 15 minutes and the large for more than half an hour. Definitely knocked the mature parasites for six - but the eggs are still present. Just need to wait and see now if the eggs hatch. If they do, then I'll just repeat a couple of more times till I break the cycle.

Mon is spot on with the sexing, its pretty easy to do. I have never seen any hermaphrodites, but this page -> http://www.dpi.nsw.gov.au/fisheries/aquaculture/publications/species-freshwater/freshwater-yabby mentions that apparently 1 in 20 can show both sex organs. The hard part is holding them still without getting nipped (even the little ones can give you a decent pinch).

The same link also states that they are happy living in saline water up to 12ppt (approx 35% as saline as sea water), but die if it reaches 25ppt.

I pulled my trap this evening, got 12 yabbies but all were quite small unfortunately. I'm keen to eat the biggest ones to give the small guys a chance, I might have to rig up a scoop net and go out with the torch tomorrow night.

the other thing, and completely unscientific, is that the females seem to have a bigger radius of reach backwards with their nippers. ie when you hold them behind their head, they can double back their claws more to nip ya the little b******es.

They definitely have a better reach backwards than marron, I never got nipped when handling the marron at all but I've had at least 3 yabbies tag me...

Used to have them draw blood from me every other week (if not more frequently) when I was a kid yabbying (or lobbying) in the dam at the childhood home. Fine memories :-)

if you upset them, they will not forget

article lifted from last Friday Herald Sun

Yes, I saw that in one of the Brissie papers too and thought immediately of VB and his yabby colony