Backyard Aquaponics
A place to discuss aquaponics

Hi,
I have set up a small scale AP system a couple of months ago and it all seems to be going well, thanks to all the advice from here and Joel's book.
I don't seem to be able to find info if yabbies/marron can totally substitute for fish in the system. Do they do the same digestive etc job?
Cheers

From the bit of research I have done, and from the discussions I have had with people, it would seem that youcan go with yabby without fish at all...
The only limiting factor is/was the number you can keep in a tank - ygetting a higher stocking density is a little more of a challenge for obvious reasons, but that is easily resolved.

I was talking with Gladstone state high school today and they have an aquaculture setup with 10 kg of Red claw Yabbies. One comment they made was their water was fairly stale and they wouldnt eat them at the end of year no matter what. I got a couple of book on red claw today and they need excellent water quality. Some interesting points from the book (from the DPI include):

1. Tanks should be covered, dark secure and preditor proof
2. Constructed of non toxic materials
3. Very rough surfaces should be avoinded as the yabbies can get damaged
4. Redclaw can stress (GSHS said this too and they have a lot of deaths due to students pick them up constantly - Id die too if i was picked up by a lot of year 9 boys too!) Shelters can help them destress
Above was from the DPI handbook on red claw.

GSHS also said that they found their redclaw to be territorial. Anyone else found this?

Hope i didnt go off topic... But GSHS mentioned some interesing things

Not off topic Mac - Simmo has some marron, EB his lot of yabbies and there some of us that are interested in redclaw so it is all good info

I have also been following your school excursion with interest

low numbers of redclaw are territorial - but it was suggested that in higher populations they would lose that territorialism... If somebody would give me say 30 redclaw I am willing to test the theory

Hmmm, they are missing out - just look at the conditions they can be found in in the wild - some of those dams are VERY dirty!

Regarding density, can you fill us in on how the school is housing the 10kg of redclaw MCPHRO.

Thanks.

Will do, im going there in the next week to check it out - and im going to take a "camera"

Ill also take a picture of where I propose to put ours. Still negotiating with faculties. They all want to see it go ahead but I have to show I have their support, also put into the curriculum. I was talking to prinicipal today and Its gotta have a few faculties support, or i might be relegated back to a classroom fish tank.... I dont care, im gonna make it happen! Mw ahahahahahah

good to see more evil teachers in the world! I wish we'd had some at my school when I was a kid.

Well, the one thing I havent mentioned yet is that im applying for a different position at school and If i get it, it might throw things out of wack because I may not get as many science classes (My main area is IT). I wont know till next week. Either way, the minister of war and finance(aka wife) is onside and I have the greenlight at home to some degree. I want to assist in getting the system up and running at school But due to budgets, nothing will actually happen till next year. So the school system regardless will take a few months to get to the "realisation stage"...

And if i dont get this new position, then I -ll be going full guns on the aquaponics side of things.

Good luck in your promotion attempt , it may slow down your AP progress but don't expect to go "cold turkey" on AP, it is now in your blood

I have 12 Marron in ~900 litres (4 tanks - 3 in each) and around 20 yabbies in 475 litres. They provide enough ammonia to sustain an AP system, no problems there, you do need to be smart about designing your system in such a way that there is plenty of shelter for the crays though. PVC pipes work well but there tends to be a build up of waste solids inside of them. I intend on using stackable slotted plastic containers (they use them at nurserys to hold potted plants) in my next system to avoid solids buildup.

Territorialism claimed 2 of my Marron initially, so now in my system I won't stock any more than 2-3 marron per m2 of floor space. With my next system using the plastic containers, I'm hoping that the apartment style housing will increase the amount of floor space enough to allow for a higher stocking density.

Yabbies can be stocked slightly higher than Marron and Redclaw but are more aggressive so expect to see some limbs lost and the occaisional death due to fighting.

The other concern if you don't stock fish is mosquito control, so I have been trialling some small native pygmy perch in my yabby tank for this job, since I introduced them there are no wrigglers visible at all.

we just got 10 stackable bread trays for the redclaw ibc

cool

Yeah, I reckon that is the way to go. They also have trouble gripping onto the pvc piping (cause it is rounded) so stackable perforated crates (in whatever form) will work well for both the crays and us.

I''m very interested in polyculture between crays and fish, and it looks like a combination of Marron (or perhaps RedClaw) and Silver Perch is possible. There have been some studies done by a professor at Curtin uni which I am chasing details for ATM.

The bread crates sound like a good idea - but I am worried about putting any plastics that are not food grade and UV stable into a closed AP system. Anything that leaches out is only going into 1 of 2 places - fish or plants.