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Yabbies

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Hello Fellow Yabby Novices,

I put 8 pairs of yabbies into my first attempt at a system see separate thread. About half have escaped or eaten themselves.

After making a system design revision on the weekend and emptying my bottom pond, I found one of my 'girls' was pregnant (see attached pics). I am going to be a surrogate father:confused:!

Only problem is I have no idea what I'm doing:eek:!!

I have separated mum from the group into her own tank with an air pump. Water is a bit green but that's another matter. It tests OK except a bit alkaline.

I have a couple of yabby husbandry questions for the forum... Not sure if anyone can help me. I am really flying blind here.. wish me luck!

(1) Are the eggs under her fertilised already? I am assuming they are.

(2) When the babies detach from mum how do I stop her eating them? Should I confine her to a PVC tube with escape holes for the babies? Any ideas on achieving this?

(3) How long until the babies will detach?

If successful I intend to keep mum and one or two other boys as brood stock and eat the rest to make way for the next generation:D!!

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My babies are going well.

Today the started to separate from mum so a shook most of them off and separated mum. Not sure if this is the thing to do but we will see.

Photos are not much good as the little ******s are tiny... Hope they can feed themselves at this early stage??? I figure that in a creek they would just get washed away and be able to fend for themselves.

Spare a thought for my original brood stock, their days are numbered and destined for my tummy. Six large king prawn sized tails is hardly a feed but we will see. Will keep mum and a partner as I am not sure about the ratio of males to females in the breeding outcome.

Anyone got any ideas on the whole process?

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Hi Martin,

My guess is that you've done the right thing by separating mum from the kids......lest she start snacking on them.

You might consider using something like frozen bloodworms for your baby yabbies......they're tiny. A small handful of well-rotted leaf litter might by useful, too. They can eat it and hide in it, too. Remember, the little chaps will be looking for opportunities to have lunch with the family (in the narrowest sense) so having plenty of places for them to hide....particularly while they are moulting....is a good idea.

Your six king prawn-sized yabbie tails would be a main course (or two entrees) in an overpriced, yuppie restaurant in Sydney.....but I agree they're hardly a feed for a committed yabbie eater.

Gary

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Thanks Gary,

I have been putting lawn clippings into the nursery and it seems to be working. Prior to this they were all clumped in a bunch. Not sure if I had separated them from mum too soon or if they were having a big brawl trying to eat each other??

Interestingly a couple of the males in my main tank I have are eating each other. Not sure if the goldfish they are sharing the tank with are eating all their pellets which is making them hungry. Maybe it's cause I have separated the female and they are just getting frustrated as blokes do?:rolleyes:

Anyway all seems to be going well. I have so many babies I think I'll get a feed or two out of this lot when they grow up. I am not sure how many I can stock in the one 2sq mtre area? Maybe I need to build them a high rise hotel out of lots of 20-40mm pipe off cuts... seriously!

Attached are some pics for everyone to enjoy.

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Fantastic Martin,

I would love to see the continued progress of your Yabbie farm. I want to have a go at it soon, but know zip about yabbies.

Hey mate, can you rotate your pix through 90 degrees.

I just rotated on for you, hope you don't mind....I will do the other ones later on if you like.

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Guest markofarm

G,day Yabbie Growers from markofarm N.Q. I,m interested in setting up an aquaponic system with yabbies as an alternative to fish. any info would be appreciated. mark

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Hi Markofarm,

Welcome to the forum. This may be very useful. A lot of our members including myself would like to raise some yabbies for our own use in our Aquaponics systems. Perhaps you can assist with few pointers please.

As for aquaponics system powered by yabbies, many are doing it, but not exclusively. Most use fish principally and yabbies.

As far as I know there would be no reason why a system would not work just as well with yabbies as it does with fish. It would be a matter of finding the balance between yabbies and plants.

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Hi,

I think that a polyculture involving yabbies, plants and fish would be the way to go. It's going to provide a more consistent supply of nutrients for the plants and some of the food for the yabbies is likely to be found in what the fish waste (and excrete).

The important thing to remember is that just about all species of freshwater fish eat yabbies from the time that they are big enough to get their mouths around them.....so keeping them separate is important.

I think that Duckweed tanks or deep water culture troughs would be an ideal environment in which to keep yabbies. You are getting two crops out of the same tank......and nothing will eat the yabbies and the yabbies won't seriously impact the duckweed or lettuce crop.

This way, while the fish and yabbies are in the same system, they do not make direct contact with each other.

Gary

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[Does anyone of what sort of rate to feed the yabbies? I've heard its about 5% of body weight for fish.

I started my system with 7 yabbies a few weeks ago, been feeding veggie scraps, earthworms etc I suspect I'm underfeeding as there are several bits of yabbies scattered around the tank. I'm a bit wary of to much uneaten scraps in the tank.

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Hi Lambs,

[Does anyone of what sort of rate to feed the yabbies? I've heard its about 5% of body weight for fish.

I started my system with 7 yabbies a few weeks ago, been feeding veggie scraps, earthworms etc I suspect I'm underfeeding as there are several bits of yabbies scattered around the tank. I'm a bit wary of to much uneaten scraps in the tank.

I wouldn't worry too much about trying to get too systematic about feeding yabbies.....or fish for that matter. I only feed as much as my fish will clean up within a short time.....a couple of times per day. If I notice food building up on the floor of the tank, I stop feeding until it disappears.

Uneaten food = ammonia.....so you're right to avoid over-feeding.

Do you have 'hides'....bits of PVC pipe or similar places for the yabbies to hide from their mates when they are moulting?

I wouldn't assume that the yabbies are hungry simply because they are attacking each other. Fighting (and subsequent cannibalism) is natural behaviour for yabbies.

Gary

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[Do you have 'hides'....bits of PVC pipe or similar places for the yabbies to hide from their mates when they are moulting?]

Hi Gary

I've got some bits of PVC pipe but fewer pieces of pipe than no of yabbies. I will add a few more.

If nothing else I'll have one big one by the end.

Lambs

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Hi Yabby lovers!

I today rearranged my system to allow me to hold my last two original yabbies as a breeding pair and then to separate my fish from the main yabby grow out tank. The boy is the bigger one and has been escaping regularly.... found him pounding the pavement last night before I had secured his new home. This pic was taken whilst holding them in my kids wading pool very temporarily!

After growing my babies in the garage in a camping dish washing up tub with an aerator I today released them into the grow out tank. They are still small (some smaller than others) but I figure they will enjoy their new home. Sorry no new pics taken before I released them.

My only concern is that I may have moved them into the grow out tank too early. They are still so small that they could all crawl away unnoticed? One things for sure, if a fish ends up in this tank he/she will enjoy a yabby feast!

Time will tell....

PS I also borrowed a couple of reference books on yabbies from the local library today so I will be doing some reading and share with you any key findings on Yabby husbandry. Apparently they can breed successfully three times in a summer season producing a hundred 'berries' at a time?? I'll post some facts and references later.

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I will look forward to learning about yabbies.

Evidently, (so I have been told) yabbies can be prevented from escaping if a very low wattage light bulb is used over the pond/tank If bright moonlight can be replicated they will not attempt to escape. I do not know if that is true, but it sounds possible.

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Hi Jonathon,

It's interesting you mention about the separation of males and females. Does this make the males more agro?

After I separated mine I had a gradual reduction in numbers due to canabalism, all the way down to the last dominant male. He ended up pretty big :rolleyes:

He is now back in with a female and I think they are mating again... they are sharing a hide head to tail??? I haven't seen that before!

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Hi Everyone,

A great reference book I got from the library is called The Australian Yabby Farmer (2nd Edition) by John Mosig ISBN 0 643 06367 6

It's a great and comprehensive book on yabby farming and also has excellent information on Australian Aquaculture principles relevant to backyard aquaponics. If your going to give yabbies a go then I would highly recommend it as a read first.

I am tempted to scan the first small chapter on Yabby Myths and Realities and post it here but fear I'll breach the copyright?

Here's a reproduction of the books Dedication....

"This book is dedicated to all those lost souls who, ever since they were little kids catching yabbies with a piece of string and a chop tail, have wanted to go yabbie farming."

.... hehe sounds a bit like us poor lost souls who have all fallen in love with aquaponics ;)

I think I have also worked out my yabby cannibalism issue by reading the book... actually cannibalism is the first myth topic :). I think I may have simply been stressing the yabbies out with little cover (clear water) and having them share a pond with an ever growing set of goldfish and one infamous silver. The goldfish were probably consuming the majority of the yabby pellets I was feeding making the yabbies hungry and stressed to the point that they attacked each other. Only natural really. :o

I am thinking that mixing yabbies and fish in aquaponic tanks really isn't a feasible idea.

I think all my new yabby babies have also been eaten by a couple of new Perch fingerlings who have managed to translocate themselves through the plumbing which connects the two ponds via water flow.... bugger!

I think I'll be saving up for another dedicated yabby growout/duckweed tank (similar to the one fishfood has going)

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I have had that text book for a good while now it is ok I do recommend it but it is not the best.

But I ask why would anyone really try to grow maybe 20-30 yabbies a go it really is a waste of time, even in my irrigation dam there really isn’t much to turn one on if you know what I mean.

As you can see yabbies need food to survive or they revert to cannibalism sinking pellets are good so are lupins or soybeans as well as algae blooms.

Off memory the book doesn’t explain the separation of male to female and its associated benefits: Basically males grow faster 30% when segregated from females due to a lack of desire to breed yet, I bet if they share the same water in different tanks it wont help due to the pheromones (I think that’s how you spell it) given off by the females.

If us males were kept away from females our whole lives I guess we would do the same too!

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I can’t guarantee how accurate sharing the same water of different sexes would affect growth but I have a feeling there would be little advantage.

Most information on yabbies is based on ‘dam culture’ so one dam for one sex another dam for another. Yet, in practice on a large scale it is not practical to separate sex for the fact if a few females are mixed into the male dam or vice versa it has just defeated the purpose.

Do some research on the net particularly Dep. Of Fisheries WA of all male hybrid yabbies where two common Eastern state yabbies crossed (1 male type 1 female type) produces yabbies that are all male (sterile to I think). I would have already done this on my farm but I can’t get one of the types of yabbies here, there not supposed to be here in WA but I have seen that type in a river in the SW of WA past the yabbie line too.

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Yes I agree... but when it comes time to eat the little buggers some may struggle?

It will be interesting to see if I can repeat the breeding next year when these ones mature. As mentioned earlier in this thread, I think I triggered a breeding cycle accidentally by virtue of a rainwater & sun inspired algal bloom in my system??

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