Yabbies

[gbj]

Hi all,

Has anybody had any experience with growing yabbies in an aquaponics system? Would you need to give them somewhere to burrow into like a mud layer at the bottom of the tank? Would it be a good (or a dumb) idea to set up a tank with both silver perch and yabbies?

Thanks

[GaryD]

Hi,

While I'm aware of a few people who have bred and raised yabbies, I'm not aware of anyone who had managed to produce really useful quantities using aquaponics.....or, for that matter, in any recirculating aquaculture system.

This seems to be borne out by what I can glean from DPI and from looking at the 'net. Most freshwater crayfish production (yabbies, redclaw and marron) happens in ponds or dams.

Some time back, I came across a web site where it is claimed that production levels of 500 yabbies per square metre of floor space can be produced using their "extreme density unit." Check out http://www.blueyabby.com/en/

I would think that the problem with Silver Perch and yabbies is that, which ever one is biggest; they will eat the other one.

Gary

[Frank]

Sorry to correct you Gary, but a bloke on eBay recently was selling these.

Said he had used them both for prawns and yabbies commercially.

Couldn't you still have your fish in there as well. Wouldn't the yabbies help cleanup the scraps from the uneaten fish pallets?

[Murray]

Frank, do you know what these white containers are that look like some sort of mini cages or similar in the bottom of the grey poly tank and stacked up beside the tank ?
Perhaps these things are a similar idea as seen in the link provided above.
I know nothing about Yabbie growing, but I would like to find out.
I have read that there have been some pretty big failures commercially because, raised in tanks, the main difficulty is to stop them eating each other.
Muzza

[Frank]

All I know from when I contacted the guy was that he had raised both prawns and yabbies at some stage in them.

Said they were pretty common over here in WA. Wouldn't sell any though, had to take the bundle and was too far away from me

Here's a picture that shows them better

[GaryD]

Hi Frank,

It's a shame that you can't provide more details about this system - it looks interesting.

The tank is a Reln 1000 litre stock trough and the crates are 15.5 litre prawn crates.

GaryD

[Frank]

Yep, unfortunately when I found it the auction only had a day to run and the bloke hasn't responded to anymore questions since the auction ended.

He wanted $1000 for the lot. Couldn't afford it at the time and didn't know what that sort of gear was worth

You seem to know about the trays, any idea where you can get them from?

How much are those Reln troughs?

Frank

[GaryD]

Hi Frank,

If I recall correctly, the RELN stock troughs are around the $500 mark.

The 15.5 litre prawn crates are available through companies like Mining and Industrial Plastics (a Brisbane supplier) or similar places. They cost about $25.00 (for the crate and lid) each.

The sort of information that I'd most like to be able to get hold of would be the number of yabbies in each crate and similar stuff. A bit of trial and error would yield this over time.


Said he had used them both for prawns and yabbies commercially.

Couldn't you still have your fish in there as well. Wouldn't the yabbies help cleanup the scraps from the uneaten fish pallets?

If I recall correctly, yabbies take 9 - 12 months to grow out to selling size. In my view, it's doubtful that this system would yield commercial quantities of yabbies. Having said that, I'd be interested in running a couple of them if they put yabbie meat on my table in reasonable quantities.

You could probably run a few native catfish (Tandanus Tandanus) or Silver Perch fingerlings in the tanks......to help keep the tank clean.

Gary

[Frank]

$25 for a crate and a lid. Wow. Bl****dy expensive yabbies. lol

And they only look small. Why not just get like those bread trays and make alid to cover them?

[GaryD]

Hi Frank,

I calculate that you'd fit about 24 of those crates in the RELN trough.

At $25.00 each for the crates.....a total of $600 and about $500 for the trough = $1100.....you'd need to produce a substantial number of yabbies just to pay for the equipment.

At a wholesale price of $15.00, you'd need to produce about 75kg just to recover the cost of the gear.......no feed, no labour, no power costs, no nothing else.

Since we don't know how many kg's of yabbies these units could produce each year, it's all guesswork from here on.

Assuming that it would take about 9 - 12 months to grow out the yabbies (one crop per year)......and assuming that each crate was capable of housing a kg of grown yabbies (which seems like a lot given the territorial and cannibalistic behaviour of the creatures) that would amount to 24kg per year per trough and 24 plastic crates.

The repayment period......just for the gear.....would be 3 years.

It might be a proposition for a backyard food producer....I'd probably invest that sort of money to buy my own yabbie machine.......but I seriously doubt that it was a viable commercial operation.

What do you think?

Gary

PS.....I think you'd find that small to medium yabbies would be able to escape from a bread crate.

[Frank]

Yeah Gary, thought about the bread crate afterwards, then thought maybe line it with some chicken wire mesh.

On your figures it seems like not very commercial for those tubs and trays.

The guy definitly said yabbies as well as prawns, but I wondering now if even get enough prawns in there.

[Murray]

I had a visit the other day from a guy who wants to buy my grow beds for use in a commercial yabbie project. He reckons the grow beds are ideal stacked on shelves / racks in his 10 x 8 mtr shed. He will get several dozen grow beds in that way.
He reckons he has found a way to stop them from eating each other and way of stopping them from trying to escape. He would not tell me either secret. (damm) Maybe he is pulling my leg !
I am going to see his place in a few weeks , so it will be interesting to see what he is up to.
There have been some spectacular failures of commercial yabbie projects because of the yabbies eating each other and escaping.
Muzza.

[anniefish]

Hi Gary,
I've just been looking at the pictures and I think you could only fit 16 boxes in the tank. Four along and four high, am I wrong? When I first read this post I assumed they used the crates to house the breeding pair, remove the male when he had deposited, leave the female, allowing the babies to excape the crate,take the crates out,then let the babies grow in the tank. But if you are growing the crays in the crates and have them stacked 4 high how would you make sure all crates were receiving food? I understand from my research they eat rotting vegetation and scavenge anything. I would be worried that some wouldn't receive enough food.
Ann

[GaryD]

Hi Ann,

I based my calculations on six sets of four crates......one stack crossways at either end and two pairs running the length of the trough which is 2400mm long by 1200mm wide.

Premised on my experience of how yabbies behave, I think I was being generous in my estimation of the capacity of these units.

Cannibalism in yabbies is arguably the biggest issue in rearing them. They are not even safe with Mum once they are hatched......and they eat each other at every opportunity thereafter. They are particularly vulnerable to attack from their siblings when they moult their shells.

As I said earlier, we can only speculate about how the system worked (assuming that it did), because we are unable to speak to the operator.

From the little that I understand of it, intensively reared yabbies will take pellets.

Gary

[Frank]

Here is the "operator" of the prawn, yabbie crate things and the eBay auction

Auction has finished, so I don't know if you can still contact.

I used the "contact seller" button so i don't have an email address.

http://cgi.ebay.com.au/Aquaculture-Fish-Grow-out-Tanks-Purging-Tanks-crates_W0QQitemZ330124785587QQihZ014QQcategoryZ20755QQssPageNameZWDVWQQrdZ1QQcmdZView Item

[GaryD]

Hi Frank,

I've attempted to contact the seller of the gear. If they respond, we'll ask them how the system works.

Gary

[sunnyside]

Hi all,

Has anybody had any experience with growing yabbies in an aquaponics system? Would you need to give them somewhere to burrow into like a mud layer at the bottom of the tank? Would it be a good (or a dumb) idea to set up a tank with both silver perch and yabbies?

Thanks

I have grown yabbies (Cherax destructor).
No need for mud in the tank. They are very easy to care for and can be harvested in around 6 months. Take care though - any toxins in the system will kill them before your plants. With care you can raise 10+ 200g yabbies per m2 of tank floor.
They like a little gravel on the bottom of the tank (to pick through), somewhere to live and somewhere to climb. I house mine in short lengths of white PVC pipe in varying diameters.
NOTE: for productivity if you are mixing different sized yabbies do not place similar sized yabbies next to each other - they will fight when they touch. Small yabbies do well next to large yabbies - as long as you feed them! The young yabbies molt more regularly than the larger (100g+) ones and in there soft new shells are too tempting a treat for the larger ones to pass...!
I have been unable to get yabbies of similar size to use pipe houses directly above other yabbies - they all want floor level homes (so I use multi-level false tank floors). They like to climb up things so I hang lengths of pink baling twine from the wire mesh covers.
If gathering from the wild - put in clean water for a couple of weeks then select only the best for breeding (colours will intensify in clean water).
You can save your vegetable s****s, cube, steam till very tender then freeze.
They love potato. :p
Tip: bait the yabby traps with small pieces of plain yellow laundry soap - forget the rotten meat.

I can't speak from experience on mixing with Perch - mixing with Barramundi was fine - the Barra ate all the yabbies pretty quick, then everything was fine!
I'd try mesh to seperate the growout yabbies from the perch, seperate tanks for the young and a seperate spawning tank.

[GaryD]

Hi Sunnyside,

Any chance of some photos of your yabby rearing operation?

Your comments bear out my main concern.....that stocking density will always be an issue for yabbies.....unless you want to try something like this...... http://www.blueyabby.com/en/Products/EDU%20Cells.htm

Since my focus is entirely on backyard food production, I'm willing to give something a go just to be able to stock my own larder.

Gary

[gazza]

how ya goin . Ivé seen the ABYA yabby system in Adelaide it looked pretty good. I'd be interested to know if you could combine the system with aquaponics.check out the site but i dont know if they will get back to you or not ,i've been waiting for ages

[Murray]

Have you got a web address for that place Gazza.... I did a Google but could not find that particular place.

[GaryD]

Hi Murray,

This is their web address....

http://www.blueyabby.com/en/

....but as Gazza pointed out, don't hold your breath waiting for them to get back to you.

Gary

[sunnyside]

Hi Sunnyside,

Any chance of some photos of your yabby rearing operation?

Your comments bear out my main concern.....that stocking density will always be an issue for yabbies.....unless you want to try something like this...... http://www.blueyabby.com/en/Products/EDU%20Cells.htm

Since my focus is entirely on backyard food production, I'm willing to give something a go just to be able to stock my own larder.

Gary
Will send you some photos of the old operation - when I get the power on and the computers setup again! Currently I have a small number of yabbies for breeding. I'm keeping the temp around 5 - 10 degrees celcius so they are in near suspended animation until I can set the tanks up again. Oxygen is supplied with battery powered bubblers (about $15 from a chain grocery store). The yabbies are currently living in the same tubes that I use for housing them in the big tanks. I use a variety of diameters and lengths of white PVC pipe. At present each yabby is in a pipe a little larger and longer than it, with a square of flyscreen secured on each end with a rubber band - (not unlike the cells you linked to). For the purposes of moving from the old property to the new - the yabbies where then put into buckets. The buckets were then part filled with water. I managed to move the yabbies across some very bumpy roads like this! That was a week ago, they will go back into tanks tomorrow (when I have enough water) - I checked one bucket this morning, no loses! (so far)
The production system looks like shallow broad steps covered in gravel. Each step has a row of pipe lengths across it that is set equidistant from the front and back edges of the step. The pipes alternate between short/narrow and wide/longer. Strips of mesh netting hangs from the wire mesh tank cover to the floor/s of the tank. Yabbies are free to roam the tanks unlike the EDU cells. The EDU system seems very high maintenance and battery-hen-like (and expensive). I'd love to hear from someone who's used the EDU system.
Cheap Yabby Motel

S*C*R*A*P PVC pipe (various diameters) - cut to various lengths
McYabby type plastic luncheon trays
Old shade cloth - cut into strip
Gravel (2-10mm)
Scissors and a hacksaw
Cheap Yabby Motel Floating Restaurant

Polystyrene Meat/Vegetable tray - cut holes in base
Coconut fibre underfelt or kitchen scourer or foam rubber (clean and cut to make 15mm thick mat for tray.
Seeds of you choice (rocket)

[gazza]

Have you got a web address for that place Gazza.... I did a Google but could not find that particular place.

G'day Murray i was going to give you that web site but it looks like Gary has already given it to you,what do you think of that system anyway.

[Murray]

Yep, I took a look at the site. You would think there would be an easier way that using all those little plastic cages, but maybe there is not. I confess I know zip about yabbie growing.

[zact01]

hi pplz

i was looking to see what fish r legal in taz and came across this site http://www.austasiaaquaculture.com.au/article.php?newsid=7478 and thought you lot would find this interesting they say they have info on growing yabbies and other fishes. enjoy

thanks

zac