Aquaponics

Hi,

Interesting article about aquaponics We have been working on to develop a aquaponics system for propagation of ornamental aquatic plants. Our preliminary studies in a fish based system with live bearers like guppy, platy, molly, sword tail with Vallisneria (male) plants has given encouraging results. No additional fertilizers or any kind of manure was given and the system was entirely dependent on the nutrients derived from the fish metabolites. What is interesting is that the rooting was excellent and sucker formation leading to juvenile plant was highest in the guppy system. We used commercial floating pellets to feed the fishes in this system. Further, it was evident that some of the systems encouraged pure culture algae to come up in such aquaponics system. However, studies are lacking and currently we are at it to quantify the nutrient load derived through these fish metabolites in such aquaponics system.

Tailor Made Fish Farm has an extensive (for us) hyonics structure, mostly producing various lettuce varieties, but also some herbs.We grow fish in recirculating 10,000 litre tanks in banks of 3 tanks, (i.e. one module). Ten percent (10[percent]) or sometimes more of this water is replaced daily. This water replacement is one of the ways in which we underwrite the health of our fish.
The overflow water is stored, then used in the hyonics trays. The content of nutrients in this overflow water, in which the fish live happily, with minimal / insignificant disease incidence, is not sufficient to meet the nutrient requirements of the lettuce, and therefore mineral and trace element fertilization / augmentation is required for the plant crop to occur at all.
The water is NOT returned to the fish tanks after being used in the hyonics system.
We produce barramundi, which are an estuarine / salt water fish, to market mostly to the Asian restaurant live fish trade.
Our fish production this year should be in the 65 to 70 tonnes range. I do not know without enquiry, what our hyonic vegetable production is.
I do have a personal, adverse, view as to the suitability of the suggested aquaponics model.
1. The nutrient load in the returned water (from the plants to the fish) will always be too great for the fish to be comfortable in. Barramundi in a recirculating system live well in fresh water from our bores, or in salt at up to 32 parts per thousand from one of our bores. If water quality in the tanks goes off, the fish die. There is personal and associated experience using our systems to confirm this statement, including experience with the return to the tanks of hyonics water, with consequent gross mortality in market sized fish.
2. The hyonics water on any commercial scale will sooner or later contain synthetic pyrethroid insecticides. Insects love young lettuce, so if you want a crop, you have to do whatever it takes, which is legal. Returning such products to your tank will soon remind you why this is a bad idea.
3. Fish do not love excess nutrients, which is why we go to such lengths to remove faeces and suspended solids from the water, and diligently monitor our water quality parameters.
Germs and fungi love excess nutrients. What do you aspire to grow - fish, or germs and fungi? They certainly cannot co-exist!
4. We have a healthy scepticism (cynicism) about the received scientific wisdom , tried so much of it at such great cost.
What we do works for us. It may be that if you have a fish, perhaps Tilapia, which can live in mud, and is adapted to it , that it may survive for longer in conditions which barramundi would find toxic, but why would you, from choice, provide less than the best possible conditions for them to live in?
5. The nutrients we put into our system are fish food pellets which are just in quantities to be instantly taken up by the fish. We then use the system design to self clean and thus remove the faecal solids (and occasional vomitus). We dare not leave these excess nutrients in the system, and feed pathogens. It is incomprehensible to me why anyone would seek to run an aquaponics system in any other way.
Jeff Titmarsh, B.V.Sc.
Raymond Terrace Veterinary Clinic,
Shareholder and company veterinarian,
Tailor Made Fish Farm, Australia.

I feel that your aqua-ponics has not taken into account the value of the plants being used. In a symbiotic system the plant and fish choice needs to be changed from something that you want to produce to a planting system that meets the needs of the fish first. Modern aqua-ponics is devoid of the symbiotic requirements that you have failed to acknowledge and problems continue to occur and other inputs are then required making the system anything but symbiotic, which is what you would like to achieve. 

What you say about symbiotic relationships is true. Aqualon combinations that are sustainable without external inputs of nutrients are rarely economical. The market driven species selection can lead to profitable aquaponic systems, admittedly seldom ideally matched. After screening plant species that grow in fish effluent, I have found few species with local value. However, aquaponic opportunity is ever-present. Hydroponic enterprises have adapted fish to their existing plant systems and aquaculture enterprises have adapted plants to their existing fish systems. Decision making is weighted toward economics rather than ecology.

Engineering design offers many challenges in aquaponic systems, often due to the failure to account for technology costs. While small scale systems seem to be able to utilized a variety of plants with high value in niche markets (like Jayarai's aquatic plants), the small scale may not pay for facility, equipment, and labor costs expended for the research and monitoring aspect of the project. Often, the entrepreneur will install a pilot scale system in order to test the ideas that are intended to lead to specific goals. However, economic realities, including slim profit margins, make the recovery of those start-up costs difficult.

Large scale aquaponic systems develop because of markets for specific fish and plants. The engineering allows for expensive facility and operating costs because the market for the fish and plant products is known and well developed. Flexibility in such systems seems not to exist, as managers fear a change will alter the cost accounting paradigm. In some cases, large aquaponic systems exist because of subsidies in the form of low cost water, utilities, or feed.

An example of a successful (based on years of continuous operation) large scale aquaponic system is a lettuce/tilapia system in association with an ethanol distillation facility. Waste heat and carbon dioxide from the distillery assist in economic sustainability of the aquaponic side of the operation. Byproducts are utilized where possible. 100% reuse of system byproducts is not present, yet this aquaponic system has been in operation for more than 15 years.