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Crayfish in system

Discussion in 'General Aquaponics discussion - Aquaponics system ' started by Bryce duke, Nov 10, 2016.

  1. Bryce duke

    Bryce duke New Member

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    Hoping that Yabbies4me will see this and make comment/help me out, or anyone else who has experience with crayfish. My sole experience with yabbies is sunlight soap (BEST BAIT EVER!!) on a bit of string on the creek bank and a hooked stick to catch them, prior to cooking them

    I put 5 crayfish in the system almost 6 months ago now in one of the DWC beds. Put a small layer of 6-10mm gravel in the bottom, some small PVC pipe and odd bits n pieces to give them some hiding spots. I figured i'd monitor it and first sign of them eating the plant roots, out they go, although i only use the DWC as a seedling raising bed, before transplanting things to the Media beds, so the roots don't really get a chance to get too big anyway before being removed

    Well, plants and crayfish have been going along great with no issues. I decided to give the bottom of the DWC bed and the air stones a bit of a clean over the weekend, as i can see a small amount of debris starting to build up (fully expected that). I removed the 5 crayfish from the bed, then proceeded to remove a further 30 that were approximately 2-3cm long, and then also in amongst the gravel in the bottom of the DWC are lots, lots LOTS more little crayfish that are between 6-8mm long.

    So, before you start, Yes, i was expecting and hoping that they would breed. I then proceeded to spend the weekend building a large tank (what my partner describes now as the Crayfish Condominium) to house all the crayfish in that gives them a lot more room to spread out.

    Basically its an IBC that i have filled from bottom to top with stacked bread crates layered alternately to get as many in (i got 18 in). This leaves a gap between each "floor" of the condo of approx 50 mm, of which i have lined each tray with shade cloth, then put several pipe pieces and then covered in gravel, then put the next layer on and so forth. This also makes removing them easy for cleaning/harvesting etc.

    By my calculations there is about 13 square meters of floor space in the Condo. I have transferred the large crayfish into the condo, and left the little ones in the DWC bed (i couldn't work out how to get them out without hurting them) so the plan is to let them grow to a size where i can catch them to move them.

    So, now I've bored you with the details, my main question is

    Am i going about this the right way to make a good environment for them, or should i be doing something else?

    If this seems ok to those in the know, i will make a second Condo to allow separation of the little ones.

    https://1drv.ms/v/s!AkH3bpAR2GkIpxOONKos4Hvo2Yj0
     
  2. Yabbies4me

    Yabbies4me Administrator Staff Member

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    Without actually seeing it, it sounds as though your condo idea is pretty good. One suggestion I would make, would be to fill that IBC condo system with water and run it for a week or so, then dump the water and refill, then go from there... Just in case there's anything on, or leaching out of the plastic trays and shadecloth.

    What are your concerns about the system?... Mine would be accessibility, not only in regards to reaching/harvesting the yabbies, but especially in regards to keeping it clean etc, the floor in particular.
     
  3. Ringer

    Ringer Active Member

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    Hi Bryce,
    You can harvest those juveniles with a process called flow trapping . It takes advantage of the crays desire to walk up stream to cleaner water. The process simulates a drought and the crays will simply walk towards any inflowing water.
    Method:
    1. Make a ramp from a piece of 90mm pipe cut in half , then line it with a strip of carpet or shade cloth . (For traction)
    2. You'll need a large container at on end of the GB . Use a pump to fill the container with clean system water .
    3. Set up the tank so as it fills the over flowing water cascades down the ramp and into the GB.
    4. Cut a small replacement stand pipe that's only about an inch tall and place in the GB . Once drained to 1 inch deep the crayfish will start looking for deeper water up stream.
    5. If you start the draining late in the afternoon by morning all your stock should be sitting in the fill tank waiting for you. Too easy!
     
  4. Ringer

    Ringer Active Member

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    What are your concerns about the system?... Mine would be accessibility, not only in regards to reaching/harvesting the yabbies, but especially in regards to keeping it clean etc, the floor in particular.[/QUOTE]

    In my opinion Yabbies is bang on here. Crays are notoriously messy and any still water in an ecclosure will quickly collect debris. So ease of access for cleaning is paramount . My experience with stacking hides for crays is they all end up crammed in the bottom level hopefully your system design will work better than my attempts to date.
    Good luck, keep us posted.
    Cheers
     
  5. Bryce duke

    Bryce duke New Member

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    Cheers for the replies guys, i never took pics of the last assembly, but i will defidently take pics this weekend as i build the next one.

    I have a pretty good flow through this condo unit, as i discovered reading the forums here before i started that they are messy, and i have a really good filter on the water just from the crays, so heres hoping it goes ok.

    I will post pics of everything this weekend as i said.

    Great idea ringer in regards to harvesting , i will do at. I did make the tray system so that i can simply lifteach tray out in turn to harvest etc, as i really had no idea how else to do it.

    I have a pretty good underwater camera that i use in my business that is rated to a depth of over four hundred meters, so it should be suitable...

    Good thinking on the leaving it run isolated yabbies, i totally forgot that in my blind mild panic whem i found all these crayfish in the system, altnough everything so far seems happy, i have been spending way more time than i have, or should in the greenhouse checking its all still ok, although hopefully the fact that i only used gear inhad on hand already and been using may have been my saving grace there, but for the next one it will mostly have to be sourced, so origin unknown.

    I did think of the floor cleaning, and i fitted acouple of drains flush with the bottom that i can dump the water with, and i also made a water venturi vacuum for cleaning the DWC ta ks, so it should work ok in there too. Best part of it i suppose is no pump etc, so amythink it sucks up simply goes into my screen bucket, so amy little buggers that get sucked upi can rwturn without harm.

    Thanks guys, i look forward to comment and suggestions after i put photos up.

    My main concern was am i wasting my time in having crayfish, but im encouraged already just from reading your comments.
     
  6. Lesterz

    Lesterz New Member

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    Hi Bryce, I have just read your post & you have done exactly as I am planning to do with red claw in bread crates. Can you let me know if this worked well for you or not?
     
  7. Bryce duke

    Bryce duke New Member

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    Hi Lesterz. Sorry, i've just been in here after being away for a while. It is very successful. I've expanded it to 3 X 1000l IBS with crayfish in , and they are breeding like crazy. i have plenty for Fish food for the catties, plenty for me to consume, i use some as fish bait when i go fishing, and i give some away they are breeding that fast. one thing i do do is keep the big males out. they are the first to go so they dont start attacking others, and i get new males every few months to put in the system.
     
  8. Lesterz

    Lesterz New Member

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    Hi Bryce, Thanks for the reply. Glad to see it all going so well. Did the crays use all the floors of the "condo", or just a few on the bottom? Do you still use the gravel on the bottom?
    Cheers Lesterz
     
  9. Bryce duke

    Bryce duke New Member

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    Hi, yes, im still using gravel in the bottom. The crays dont seem to use the top 2 layers much, but they live happily on all the other layers. They are however really active on the top early evening when i feed them. They come up when i tap the side, and i mean they swarm.. i feed them, they grab bits and then dissapear. If im late feeding them, they are up top waiting.
     

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