Backyard Aquaponics
A place to discuss aquaponics

Hello,

My family has just acquired a fish farm with 9 ponds. The water of the pond is pumped from the river nearby and it flows from pond to pond and goes back to the river again. We had purchased around 80k tilapia fries and the prices of fish pellets are killing us. After some research on the internet, I found some alternative food source e.g. duckweed for my fish and found aquaponic rather interesting because I'd like to use it for our farm to grow some veggies for my family and feed the fish as well... but most of the information here is about using fish tanks in smaller scale. Can anyone shed a light on a beginner like me with their experience on aquaponics on ponds (our pond sizes varies - about 15m x 7m)?

Thanks

Do you have any pasture land that a high protein fodder grass can be planted? I purchased one of these pellet mills even though at my scale it wasn't justified financhally but I just wanted eventually make my system sustainable. I purchased without the motor because of shipping costs and I can get small engines cheap. At your scale it would be justified.
http://cgi.ebay.com/Pellet-Mill-Produce ... 7C294%3A50 If you google around you may find something closer to home. You could use the nutrient rich water from the last pond for irrigation of the alfalfa or lab lab. There is a video on this site:
http://www.pelletpros.com/id85.html

Aquaponics is a recirculating aquaculture system that uses plants to use up the nutrients that come from the fish waste that is converted to plant usable nutrients by bio-filters.

Since your ponds are fed from a river and drain to a river, your nutrients are likely to be rather diluted. In order to make aquaponics viable you would probably need to reduce the amount of water you take and release back into the river and then you will need to add pumping to your system and bio-filters to make aquaponics work. Probably not a cost savings when you are currently able to run your farm by letting the wastes go back to the river (perhaps not as good for the environment but if cost is your only concern, then converting to aquaponics probably won't save you in relation to your current system.)

If you have a pond with no fish in it, you might be able to grow a portion of duckweed to supplement you fish feed. Another recommendation for supplementing fish and human feed would be to grow moringa trees. I've also found that tilapia like sweet potato leaves. However, I've heard that supplementing much more than 30% of the tilapia feed with these other options will reduce production and take longer to grow the fish out to salable size.

So, land ponds could be used as part of an aquaponics system but aquaponics is a closed loop or recirculating system which is different from your open loop system with the river water.

You'd also need to be aware of the nutrient load that might be discharged back to the river system... and any regulations that might apply...

With all ponds stocked at maximum... and a constant flow from pond to pond ... the nutrient load could be significant... especially in the last few ponds... difficult to manage... and possibly significantly affect down stream wildlife and water quality when discharged back to the river...

You might be better to consider using the last pond(s) as a "settling" pond(s)... from which you could irrigate any aquaponics system (returning to the pond).... and then perhaps employ reeds and marshes to further filter the pond discharge before release back to the river..

Comercial deer food plot seed mixes often boast of crude protein of clover type alfa alfa mixes of 18 - 28% crude protein and other varities of green turnips of up to 34% crude protein. And that is not even getting into the lab lab, clay peas or soybeans. You should be able to raise a large amount of fodder using your pond effuent, well over a ton per acre.
http://web1.msue.msu.edu/fis/research/2 ... 20coop.pdf

I recommend you have a look at the following paper "integrated agri-aquaculture systems"

https://rirdc.infoservices.com.au/downloads/03-012.pdf

Great link thanks Joel.

Hi. You are very lucky to have all the water you need from a river. In my experience, tilapia grows best in green water (lots of algae to 30cm of secchi disk) and not in clear water. In fact, we hardly change water in grow out ponds but just replace water lost thru evaporation and seepage. By reducing the amount of water you flow back to the river, you not only increase the nutrients in the water ( as TC suggests) but also cut costs on feed and cost of power to pump with environmental effects as a bonus. Like algae, duck weed is good feed but is not a complete diet for tilapia. I now have a hapa net inside a tilapia pond with an experimental raft type AP. It has been there for only 3 weeks and it's still a little early to say if it's good or not.

Yes algal blooms is the common way to grow Tilapia ,, i do it that way on my farm in Thailand.
You will probably find that algie will be a dissadvantage for your plants ,, build up on the roots eventually causing root rot ..... but it is worth a try.

Another GREAT food for Tilapia is "Moringa" ,, not sure what the Tagalog word for that is.

It's "Malunggay" Chapo.

I grow that and it makes up around 30% of the Tilapia food , easy to grow plants very close together cut at 1 metre high to make many leaves. Saved me money on pellet food. Also good for pigs/ cows/ etc.

If your using algael bloom for pond grow out Cris... I suspect you're probably liming...

So I figure your pH is around 8.0-8.5.... not a good pH for nutrient uptake for plants... other than perhaps phosphorus, all the major trace elements will be locked out...

Rupe ,, near anyone with ponds LIMES,, once a year or two water drained completely ,, mud at bottom of pond allowed to dry ,, lime spread around to kill deseases etc.
Supply water PH would have a far greater impact.

True Chappo, and I'm aware of the procedure... that's the point I was alluding to... that it's done to promote a specific pH for bloom production... among other things..

Source water would indeed be important.. but anyone running bloom management in ponds wouldn't be using source water that was anywhere beyond pH 7.0... and even then would be managing pH toward 8.0..

At that desired pH... nutrient lock out for plants is a major factor... other than phosphorus... which will impact/limit plant growth of most plants, other than perhaps lettuce... watercresses and similar may do alright..