Backyard Aquaponics
A place to discuss aquaponics

I'm planning my new system. I have 2x 400L tanks, and intend to have one for fish and one for yabbies.

The formal aquaculture guff says 4-8 yabbies per square metre of pond, and it seems they are talking about ponds at least a metre deep. Based on that, I'd only be able to raise about half a dozen yabbies at the most. Given that they take about a year to grow to edible size, it seems like a lot of messing around to eat just 6 yabbies a year!

Does anyone know if the growbed filtration of aquaponics allow us to stock yabbies significantly more densely than in conventional yabby ponds? For instance, if I could raise 20 or 30 in a year it would be a whole lot more worthwhile.

I'm thinking of circumventing the issue of breeding, and instead simply going yabbying once a year in my Auntie's dam, and selecting the tiniest critters to "fatten up" in my system, leaving the mature ones behind to continue breeding in the dam. I'd be the only one doing this, and I'd only be taking 20-30 each time, so it's not going to drastically plunder the stocks. But if anyone foresees a major problem with the idea, please let me know.

Jimmy

Yabbies are not particularly sensitive to water conditions the only problem is territorial fights. Provided you can provide enough places for them to hide/moult and enough food you shold be able to have significantly larger populations than suggested.
They are also great escape artists so stopping them 'wandering' will be a concern.
The other matter is introducing 'undesirable' elements from the wild stocks, into your system. Gilgies which I have breed without any problems.

Thanks Sleepe.

Do yabbies excrete ammonia? Should I have a yabbie-only system and a separate fish-only system, or connect the whole lot together so the same water cycles through everything (albeit with fish & yabbies in separate tanks to avoid conflict)?

Yabbies do excrete ammonia mate. There shouldn't be a problem with having the yabbies and fish in one system. Unless you do bring some parasite/disease from the yabbies you have collected from the dam.

I suggest you give them a salt bath to rid them of any nasties and then keep them in a tank for a couple of days and then repeat the salt bath before adding them to your system.

30gms of salt to 1 liter for 3 Minutes. Yabbies have a high tolerance to salt.

Thanks for the help!

Yabbies in the Sump, Fish in the FT.

Sounds good to me.
Tony

Of course this kills my plan for a little 12V bilge pump in the sump. Having yabbies in there will mean the pump needs to handle solids.

Anyone aware of 12V pumps that handle solids?

How big is a Yabbie poo?

Not sure. I'm also thinking of any uneaten food, too.

never really seen any Lungy... Guess it's pretty fine. Not liek the 'tails' you see on some fish

So perhaps I might get away with a 12V blige pump after all?

With a bit of brain storming the possibilities are endless mate.

i am planning to put marron or yabbies into my 100lt sump tank. I thought of putting various sized offcuts into the sump to provide hides for them. Smaller diameter in the bottom, then progressivly larger towards the top. Hopefully young ones will fall to the bottom of the tank and be able to hide from the larger ones. As they grow they will have to move up the tank, so the largest will be at the top for me to harvest.

what do you APers reckon??

I reckon a 100 litre sump is pretty small and that by the time you put the offcuts in there, there will not be much room for the pump and water :-).

The idea is sound other than that. I have about 20 - 30 cherax destructor in a 50 litre aqauarium at the moment and it is only half full of water. Have offcuts for hideys, though many are not in them. They seem to shape up to each other a bit, but in a week there have been no deaths and nobody doing major damage to each other.

PS - should mention that by all accounts this is quite unusual :-/