Backyard Aquaponics
A place to discuss aquaponics

thought so, it looked familiar

Sorry, catching up on the thread.

My thoughts (for what they're worth)

GBs - I'd go with terraced lined ponds - cheap, fast, easy.

Gates of El - I'd go with one or two fixed gates, then two or three sizes of nets in the movable section. Use a large flap of the net material as your interior hinge. That way, you can walk then net around the dam, keeping it fairly flush with the outside edge, and catch whatever in the loop of net fabric. If you make a beam to the center post of the dam, you can make the movable portion out of a single post (weighted at the bottom, and floating at the top) that you could go all the way around the Dam, and back up to the center, creating an even smaller area to net the fish out of.

For the Baboons - An electric fence in one area would be good, but have a small stand of something that they like to attract them away from your real crops. That way they say, "oh, that looks good...Ouch, I'm not going to mess with that, but right here, we have something that's easy to get to that's almost as good....I'll eat that." Alternatively, if there is a type of animal that baboons hate, but doesn't bother you you can attract them. Otherwise, use the baboons' fodder to keep other things away from your crops - they seem capable of handling most other things...

Growing things around the Dam, You could do floating rafts, but the Tilapia might eat all the roots. You could do floating rafts with caged roots, that would make use of the area, but let you pull stuff out to simplify harvesting the plants and the fish.

Still stocking my broodfish dam. Yesterday, when the temperature dropped to a "mere" 33 degrees at 4pm I fetched some fish from a neighbouring farm and introduced them. Some photos.

I now am faced with numerous challenges to overcome at the dam and in order to get some clarity I think it would be easier to list them and briefly discuss each of the problems we face.

Predators.

Birds have now discovered the site and bird netting has become vital. We have seen and heard fish eagles and they will easily take out even the bigger fish, and last week we surprised a comorant perched on the dam wall watching the fish. Being 10km from the sea, this was quite a strange site. The fingerlings were very nervous and swam very closely together in a very tight school. By the weekend I had lost most of my small Tilapia.

I basically had two choices, either buy a box of pellets and shoot him, or invest in the bird netting which was far more expensive.

Being nominated for the Best Green Blog in the SA Blog Awards obviously ruled out the former, so I'll have to take my chances with the Child Bride when she finds the invoice for the netting. The larger red Tilapia seem OK, which means that the Fish Eagle hasn't paid a visit yet, but the netting should keep him out as well.

Power

Although there is an Eskom (our power supplier here in South Africa) transformer close by, this is going to cost money for availability and in any event is not that reliable, which leaves solar and wind power. I have priced a small solar pump which, without a battery and inverter seems rather steep. This unit pumps only when there is sun shining directly onto the panel. I could spend a bit more and store power in batteries and then have a more even supply, but I still doubt whether this will give me 12 hours of pumping (½ hour on and ½ hour off) per day. The other option is a wind turbine. We have recently been appointed agents for the Kestrel wind turbine, manufactured by Eveready in Port Elizabeth, South Africa, so I will definitely install a test unit at the hatchery site and see how it goes.

Capture

I have now constructed two Gates of Ell so capture should be easy. That's of course if the birds have left me anything.

I had to flood the pipes with water to prevent it from floating to the surface, and we have just attached it to the centre pillar with rope.

We also continued with our retaining wall of old tyres and I have now decided to have three levels from the top tanks to the bottom level, with a fourth level being right at the bottom where the sump will be.

Next week the big (30m x 10m) greenhouse arrives for the commercial site and we are also getting a second tunnel at the same time which I will be erecting for another client.

The 4 ponds at the commercial site are now full and cycling on bio-filters until we build the grow beds. I have 16 very large Koi in the one and about 100 Tilapia fingerlings in another. We are using 500mm PVC pipes cut in half for GB's.

looks promising!

That center column came in very handy. Watch it with the cormmorants if they figure out that they can get easy pickins they will start showing up in greater numbers till they clean you out.

What are the chances that an Eagle will attempt the fish through the net? Might want to think of adding something to make the netting slightly more noticable?

Wow, these are awesome projects. I look forward to seeing how it comes out.
I wish I could help with the baboons, but like emsjoflo, bears and moose are more of a threat to me (or in my case, ferrets )

Would those motion-detecting sprinklers work?
http://www.greentouchirrigation.com/scarecrow.html

Of course, that's just another thing using electricity and water...

You mentioned the 'local situation deteriorating.' Have you explained that more elsewhere?

emsjoflo
thanks.

badfish03
Yes, the centre column certainly did come in handy. I wondered what it was for when I first moved in As far as the fish eagle, good idea, maybe some reflectors?

swanberg (Karen)
Yep, politically it's getting quite difficult at the moment for us "white boys". There are no jobs for us, no contracts, no tenders, no bursaries for our children, and not much more us to stay here for. I fought tooth and nail against Apartheid and racism. Nothing has changed, it's just that now we are the folk being discriminated against. I am desperately trying to get an Aquaculture permit to farm Kob (Mulloway). A major stumbling block seems to be that I am white. My skills, abilities and capital mean nothing. Our electricity supply is failing because they purged all of the white folk who had the skills to plan and keep things going. The same will happen with our water supply, sewerage treatment, roads etc. etc. all in the name of "affirmative action" I'd just like to make my Aquaponic dreams come true somewhere where I am appreciated for my skills and not the color of my skin.

Hi Synaptoman,
Looks like you are making great progress despite the bird problems.

That central column in the tanks would make a fine perch for a small simple windmill, extend some lightweight arms outwards to sweep the tank like a boom..maybe add some bright streamers to it too.

It`ll give the birds a good slap if they get too close to your fish

Yeah something reflective is what I was thinking maybe pie tins so they can spin about a bit.

another easy reflector to use is old CD's

OOOH I like that very shiney

Catfish, bluegill and Bass around here might go for them don't know if it will set Tilapia off.

I listen to all my old CD's In fact I only HAVE old CD's. Come to think of it I don't even have many CD's. I suppose old LP's wouldn't be as effective.

no stuffed ones from the pooter?

Depends.... playing them might be enough to drive anything away