Interview with Dr. Wilson Lennard.


1) How long have you been in the aquaponic industry?

I have been in the aquaponics industry since 2005, when I started by designing and constructing my first commercial system. I have been formally studying aquaponics since 2001, when I started my PhD in aquaponics at RMIT University, in Melbourne, Australia. I have studied aquaponics in terms of doing literature searches etc…since about the year 1999, when I began looking for a way to treat RAS aquaculture effluent and I became aware of aquaponics in the mid 80’s when I was at University studying for my bachelors degree.

2) Why/How did you get involved with aquaponics?

I guess my formal involvement began in 2000 when I decided I was sick of working on short term contracts doing science work in Australia. I just moved from one year contract to one year contract and decided that I would be better off studying something and becoming an expert and working for myself; if possible. I initially applied for a $300,000 grant to study aquaponics, but was rejected. However, the agency (Rural Industries Research and Development Organization) offered me a PhD scholarship instead. This involved a drop in income, but I could afford it so decided to do it. Once I got the scholarship I approached my old University and they couldn’t say no (they like it if you approach them with sourced income and funds already!)

Aquaponics for me, like many others I think, just made complete sense. I had been an aquatic ecologist and aquaculturalist for many years and saw the problems associated with nutrient-rich wastewater releases, so found it made sense to use the waste nutrients for something else. I saw ahead a bit and decided that these environmental impacts would be tolerated in the future, so decided aquaponics was the industry for me.

No one even knew what aquaponics was when I started. I kept telling people I was trying to optimize commercial aquaponics and the only reply I got was “what is aquaponics?” I also presented early at scientific conferences and had aquaculture and hydroponics people actively telling me I was kidding myself and that aquaponics was a load of crap. The main players in aquaponics in Australia contacted me very early to pick my brains. Of course now they won’t admit to that!

Jim Rakocy ended up being one of my PhD thesis examiners and we have become firm friends and work together whenever possible. I am also friends with Nick Savidov in Canada and we are trying to work together as well. We all share experiences and data with each other and have know each other since about 2004. There are other researchers now looking into aquaponics, but Jim, Nick and I were the only three doing anything just a few years ago. It is funny how quickly things can change sometimes!

3) Do you think aquaponics will eventually become the primary form of agriculture?

No, aquaponics will definitely not become the primary form of agriculture at any time. The most important agriculture products, the ones that feed the world, are the cereal crop staples which provide basic carbohydrate requirements for us all, things like Rice, Corn, Wheat etc…These are broad acre crops and we grow millions of hectares a year globally and they are broad acre crops, so aquaponics will never grow appreciable amounts of these crops. I do think aquaponics could take over the hydroponics industry and we could move towards aquaponics dominating market garden vegetable production, but that will be about it.

4) What do you think the future of aquaponics will bring?

I think the future of aquaponics is small, decentralized growing systems that will be set up in cities and towns throughout the world. I see that there will be large aquaponics facilities, like there is for say hydroponic tomatoes, but the major use will be small systems in urban areas. This sort of goes against what many people think currently; there are many companies who are interested in building large systems that are acres in size. But, oil is running out and we will need food grown close to where we live again (like in the past), so I believe the time for the small scale farmer is returning. This is the future and I think aquaponics technology fits to it perfectly.

I also think that systems will become better designed, but there is a phenomenon in technology evolution whereby the first 90% of the optimization is done quickly and the last 10% takes years. I think we are at the last 10% stage now with aquaponics. I also think people will start to move towards the most efficient aquaponics approaches possible, to use as little water as possible and to use as many nutrients as possible. I think people will start to adopt models of aquaponics that move towards more optimized and efficient approaches, because this is what the world needs.


5) What are your views on incorporating earthworm research into aquaponics? Do you think eliminating the need for fish meal or oil in fish feed could change aquaponics as we know it?

I think fish oil and fish meal replacement is the ONLY way we can go. Aquaculture is a great approach, but the sourcing of the feed for aquaculture from wild fisheries does nothing to help the world and make us all develop a sustainable future. I think aquaculture will develop species of fish which can be easily grown using plant material. Fish like Grass Carp and Silver Carp convert plant protein in a very efficient manner. These fish will then be grown to produce fish meal and fish oil which will then be fed to the fish we like eating, like freshwater and marine carnivores.

However, I don’t believe worms are a wonder food that will replace fish feeds entirely. Worms can be used as a supplement but will never make a complete fish diet. I think invertebrates can play a big role in feeding freshwater fish, but I don’t think the bulk of the fish diet will come form this, it will come from plants.

Worms work well in aquaponic systems and many people use them to process solid fish waste. I personally don’t sue them any more as I now use microbiological solids mineralization in my systems. However, I am looking into them for my low-tech, developing world designs as they would make a good fish feed supplement.

I am currently working with a system I designed in New Zealand where we grow Grass Carp as the fish and we have produced a fish feed pellet entirely sourced from waste plant materials and Duckweed species grown on wastewater ponds. This feed has been researched by the Berrysmith Foundation (www.berrysmith.org), a New Zealand Foundation started to educate the world about sustainable food production practices. The plan is to feed this food directly to the fish in the aquaponics to “close the loop”, so no external fish feed other than plant waste products is required. Many people do not understand that it is impossible to design a fully closed biological system and that any talk of “completely closed loop aquaponic systems”, in terms of zero inputs to the aquaponics from external sources, is impossible. The only closed loop biological system is our planet Earth, and we are currently doing a really good job to prove how easy it is for one selfish species to screw up that balance.


6) Are there any aspects of aquaponics you are researching currently? If so, what are your hypotheses?

As I said above, I am researching the system in NZ. It has an aquaponic system and a standard hydroponic system side by side in the same greenhouse. This is so we can compare growth of the plants in both systems. Current outcomes are that the aquaponics is growing plants bigger and of better quality. We also had an influx of unsterilised river water enter both systems, which introduced a plant pathogen called Pythium spp. This Pythium spp. caused havoc in the hydroponics, affecting everything so it wouldn’t grow properly and died. The operators needed to use sprays and additives etc…to get rid of it. However, the aquaponics couldn’t use any of these and basically, didn’t need to as the disease rate was virtually zero. This shows that aquaponics, with its biological approach, has other advantages, like disease resistance.

I am also looking at the fish food issue as outlined in the last question.

My passion is to design and produce low-tech aquaponic systems to assist developing world peoples to grow protein and veggies for themselves. I am hopefully going to do a project in India to design and construct an ultra low-tech system to put into an Indian village to help people feed themselves using water and nutrient efficient approaches.

I am also being included on a “vertical farm” project which will build a 6 story building and use it to grow food; aquaponics will be one of the major growing technologies used.

I am also building my own aquaponic system which will operate as an independent business and demonstrate to people that you can turn aquaponics into a successful business. I currently have my own approach to aquaponics design and management which relies on exacting models to predict fish to plant ratios and then uses a management approach that compliments this. I have field proven models for omnivorous and carnivorous fish and models for leafy greens (lettuces, herbs etc…). However, whilst I also have models for the fruiting plants (tomatoes, cucumbers, peppers etc…) I haven’t field tested them yet in an operating aquaponic system environment, so part of my system build will be dedicated to continuing the research I need to do to get these models sorted and proven.

My main hypothesis, which I have been working on, now for almost 10 years, is that aquaponics can be optimized and made more efficient. In a business sense, everyone pretty much agrees that the majority of the income and profit is generated from the plant sales, not the fish. So, my approach is to use as few fish as possible to grow the plants to market quality and quantity. This way, I spend less money on the fish system construction and less money on feeding the fish and running the fish component, and therefore, generate the maximum profit from the system because my up-front capital costs and ongoing running costs are less. As an example, my design approach uses less than half as many fish as most current commercial aquaponic models. This means I spend less than half as much on the fish system and less than half as much running the fish component, so my systems have more of a chance to be profitable and economically viable.


7) Do you think aquaponics should be incorporated into the classrooms? If so, what parts of it do you think should be taught?

Yes, aquaponics is an excellent teaching tool that can have an input to the learning of nearly every subject in school. Biology, Zoology, Botany and Chemistry are givens because these are biological systems that use water chemistry to run and contain fish and plants. Mathematics too is required for system design for flow rates etc…and Physics comes in for studying water velocities and gravity flows etc…Social studies can be included because societies adoption of sustainable technologies is a big subject at the moment. Environmental studies can also be included. So too can the arts subjects, like graphic design, industrial engineering and architecture for the design aspects of systems. So, aquaponics has a place in nearly all subjects studied in school and I think all schools should consider having a system. It also helps kids do things which are practical, which is always the best way to learn. I don’t know about you, but for me, it is much better and easier to learn if I want to know about water chemistry to keep my fish alive than just reading about it in a text book. Its also better to learn about the physics of gravity water flow if I do it to design the pipe sizes for my aquaponics systems, than doing physics problems from a text about someone standing on a train throwing a ball in the air and trying to work out how fast the ball is traveling!

So, it should all be taught. But more importantly, I think you can relate almost all subjects to aquaponics and a system will allow hands on learning which is the best learning for most kids.


8) If you had any advice for someone entering the aquaponic industry what would it be?

Well, I would say a few things:

1/ Make sure you learn what you are doing. There are people entering the industry at the moment who are saying they are experts in aquaponics. I have almost 10 years experience and don’t think I am an expert, so those that say they are, are kidding themselves and everyone else. I am trying to be a consultant, but it is hard, because I constantly question myself as to whether I know enough to tell others how to do it. Make sure you learn as much as you can both practically and theoretically. I know too many people who work in the backyard or domestic industry who know very little theory and design poor systems because of it. That theory is freely available, so it should be used

2/ Grow a thick skin! It appears that aquaponics is full of people who like to criticize others all the time. You need to be able to say “that won’t affect me”, because it can put you off working in the industry. The fact is that aquaponics is a wonderful technology and there is no single way that it works best. The beauty of aquaponics is that it can work in many different forms. But, people seem to like telling other people that they don’t know what they are talking about and that they are wrong, just because it is different to what they think.

Scientific and technical break-throughs come from people with thick skins who don’t care that anyone else thinks they are crazy!

3/ Learn business! I wish I could find somewhere to pay me a wage for the rest of my life to do my scientific research and then I could release all that I know freely to the public. BUT, I cannot do this because there is nowhere in Australia that will offer me this luxury. Therefore, I have had to turn to private business and consulting to try and make a living for myself. So, I have had to learn something I didn’t really want to learn; Business. You need business skills to make money and a living for yourself and that is that. I get too many emails form people who love aquaponics and want an aquaponic business, but have no idea of what they want to grow, who they will sell it to and what price they expect to get. No-one owns an aquaponic business; you own a fish and plant sales company which uses aquaponics as the growing technology. I have quickly learned that knowing the aquaponics is only about 20% of the business, the rest is sales prices and what to grow and who will buy it form me.


9) Do you believe it is more important to have aquaculture knowledge or hydroponic/botany knowledge to excel in aquaponics?

I think you need both. Hydroponics and plant culture is very important because you make your income mostly from the plants. However, the fish component is what drives the system and some fish can be difficult to keep and grow. Both sets of skills are needed and this is a major stepping stone for aquaponics at the moment. Many backyard and domestic people “sell” aquaponics to people because it is easy to do. This is true for small domestic approaches. But, when it comes to commercial production requirements, it gets hard! You need both sets of knowledge, and then you need the integration knowledge. I don’t see myself as knowing a lot about fish culture or hydroponics; but I concentrate on the integration knowledge. If I want to build systems for people, I can get a fish culture expert and a hydroponics plant expert. But, I cannot find an aquaponics integration expert, because there are so few of them out there. So, I think you need all of this knowledge. I think form now on, more people who understand all these experts will become more available as the technology spreads.




Interview with Dr. James Rakocy :


1) How long have you been in the aquaponic industry?
33 years

2) Why/How did you get involved with aquaponics?
It started a long time ago. I always liked to fish as a child. In junior high school I transferred that interest into raising ornamental fish in aquariums in my basement. I owned 17 aquariums. A man from the county zoo came over and showed me how to set up filters that consisted of side tanks where aquarium plants were grown to remove waste nutrients from the fish. After getting a BS degree, I lived in Africa for 2 years as a Peace Corps Volunteer. I saw a lot of malnutrition and became interested in food production. After the Peace Corps I obtained an MS degree in environmental biology and learned about water chemistry and wastewater treatment. Finally when I went to Auburn University to obtain my PhD degree, I had the opportunity to combine all my interests and raise tilapia in recirculating systems that treated the wastewater with plants. Some of the plants were aquatic plants with no value like water hyacinth or duckweed, but I also raised watercress and water chestnut, which are valuable food plants. I also added aquarium plants to the system and sold them to aquarium stores. My job at the University of the Virgin Islands was a dream that came true. I’ve had a 30-year opportunity to develop and refine a commercial-scale aquaponic system for the production of fish and vegetables.

3) Do you think aquaponics will eventually become the primary form of agriculture?
No actually. Maybe I am shortsighted because I never anticipated the current widespread interest in aquaponics, but I see aquaponics as just one component of agriculture designed for high value niche crops. I see aquaponic systems being located next to urban centers to reduce transportation and produce very fresh products. I doubt that aquaponics will even produce staple crops like wheat, soybeans, rice and corn. Aquaponics will not produce fruit crops or livestock.

4) What do you think the future of aquaponics will bring?
The future will bring hundreds, maybe even thousands of modifications to improve system design, reduce construction costs, increase efficiency and maximize production. So far aquaponics really has not made a significant contribution to food production. Most of the systems being used today are backyard or hobby systems. We need to enter a phase of large-scale commercial development. We need investment and trained aquaponic practitioners who know what they are doing. The investment money has yet to come. We are trying our best to train people through our short course.

5) What are your views on incorporating earthworm research into aquaponics? Do you think eliminating the need for fish meal or oil in fish feed could change aquaponics as we know it?
I think vermiculture (the culture of worms) has a role in aquaponics. Many small hobby operations using media-based systems add worms. Worms are excellent at digesting organic waste to produce a high protein product (the worm) and worm castings, which are worm feces that represent composted manure rich in nutrients and highly desired by gardeners. I never recommend media-based systems for commercial operations. They are more difficult to construct and they can clog. For commercial operations I would not recommend adding worms to the system. A customer at a supermarket does not want to find a worm in his lettuce. However, the solid waste from the system can be composted with vermiculture.

I don’t think eliminating fish protein or using an all-plant protein diet would affect aquaponics must. All-plant diets could decrease fish growth. I don’t think there will be much change in the nutrient levels because you would still have to be using a 32% protein diet. A tilapia diet only consists of 5% fish meal. This low level of fish protein has a large affect on growth. Substituting plant protein for fish protein is more of an environmental issue than an aquaponics issue.


6) Are there any aspects of aquaponics you are researching currently? If so, what are your hypotheses?
Right now we are evaluating different techniques for removing solid waste. We are looking at parabolic screen filters and swirl separators compared to our standard technique, clarifiers flowed by filter tanks. We want to find an easier, cheaper and more efficient method for removing solids. We want a system that uses less of a footprint (takes up less space). However, we have to be careful in modifying the system because when you change something there can be unintended consequences.

7) Do you think aquaponics should be incorporated into the classrooms? If so, what parts of it do you think should be taught?
I have been told that 1000 schools in the US are already teaching aquaponics. At the beginning of the semester students set up a system and operate it through the term, producing fish and vegetables. Having a system to work with generates a lot of interest while a wide range of topics are covered. When students can see the application of principles in a practical situation that generates intense interest, they will remember them and use them in their life rather than forget some dry textbook lessons.

8) If you had any advice for someone entering the aquaponic industry what would it be?
Study as much as you possible can before you start. Read everything you can. Take one or more courses. Volunteer as an apprentice without pay to gain practical experience. Visit hobby and commercial operations and talk to the owners and employees. Plan carefully and conservatively. Build and operate a pilot system before you make a large-scale investment. Only half the challenge is growing food. The other half and equally important challenge is selling it at a profit. You must pay close attention to marketing.

9) Do you believe it is more important to have aquaculture knowledge or hydroponic/botany knowledge to excel in aquaponics?
Most importantly you need a good science background in biology, chemistry, physics and mathematics. If you have good fundamental knowledge you can learn whatever else you need to learn in life. You should have some construction skills. We spend a lot of out building things. Knowledge of electricity, plumbing, carpentry and masonry are very important. Of course you will need to learn the basic principles aquaculture and horticulture. Later you will need to learn about business, finance and marketing. You need to become a renaissance man of agriculture.


Interview with Dr. James Dixon:


1) How long have you been in the aquaponics industry?

About two years.

2) Why/How did you get involved with aquaponics?

I was searching for a way to grow a large amount of high quality herbs and leafy vegetables for local restaurants in a limited amount space. The city of Royal Oak has become a Mecca for high-end restaurants in the Southeast part of Michigan over the last twenty years. My brother was a chef for seventeen years and was well connected to the local scene, so I had a fairly good idea that we could sell this type of produce to his local chef friends. I spend part of the year in O’ahu, Hawaii, and while having lunch with the Dean of a local business school all she talked about was this aquaponics farm on the Big Island of Hawaii that she had visited. I became intrigued with the idea of being able to produce multiple crops that can be sold from the same system. It also looked like the systems were very robust as compared to classical hydroponics systems and are very good for growing leafy green type vegetables. I built a small experimental system to look at the various types of growing media in December of 2008. I later took a one week course at the farm on the Big Island in March of 2009 that my friend had visited. I came back to Michigan in May of 2009 and started building our systems in the parking lot of a commercial building in Royal Oak. We now have two systems running and are in our first production cycle for our produce.

3) Do you think aquaponics will eventually become the primary form of agriculture?

No. Aquaponic systems are really good for growing high margin niche crops where freshness and quality are important. There is a growing movement for buying local whenever possible and these systems fit that business model very well.

4) What do you think the future of aquaponics will bring?

Well, I think there will be a growing number of these systems of all different sizes being constructed in the United States and world wide. We have one of the first commercial systems in the state of Michigan and have generated a lot of interest from local consumers. It is a very compelling story to tell and it strikes a chord with a people. I recently spoke to a fellow from Michigan who was talking about converting an elementary school into an aquaponics facility – about 20,000 square feet of growing space.

5) What are your views on incorporating earthworm research into aquaponics? Do you think eliminating the need for fish meal or oil in fish feed could change aquaponics as we know it?

Earthworms provide a way of helping to close the ecosystem loop in aquaponics systems. They can process the green harvest waste from your aquaponics system and provide an important source of protein for your fish or other animals. There is a big drive to go to plant protein feeds for fish, primarily from soybeans. One of the problems of using these feeds is making them palatable to fish. We think that a ground meal of dried earthworms may offer a solution to this problem. Accordingly, we have been speaking to potential academic collaborators at the University of Rhode Island food chemistry group to formulate some fish feeds with worms. This would further reduce our dependency of wild fish as a source of protein in fish feeds.

6) Are there any aspects of aquaponics you are researching currently? If so, what are your hypotheses?

As I mentioned earlier, we are interested in making the system as sustainable as possible from a fish feed viewpoint. We are also interested in designing systems that are very energy efficient, as this lowers operating costs which go directly to the bottom line. One design goal is to have support systems that can be phased in as needed. By that, I mean if you have more fish or a higher oxygen demand load more aeration can be added to the system by turning on a pump.

Another area of research is to run low loaded fish systems with nutrient supplementation with worm compost tea which we call vermiaquaponics. Most of the profit in aquaponic systems is in the plants and not the fish. The cycle time for the plants in the system can be as short as three weeks in many cases, whereas the fish cycle can be six months or more. From a business model standpoint, to be profitable, you need to focus most of your attention on the plant side of the business.

Our design interest is also skewed towards the smaller systems that can provide 20 to 30 pounds of fresh vegetables a week in 200 square feet, about the size of a one car garage. Ideally, the system would cost under $5,000 and allow the person to recoup the cost of the system in about 18 months or less. We would also like to run the system on less than 1 Kw daily to keep operating costs to a bare minimum. This would also allow a modest sized solar panel system to be able to power the system off-grid.


7) Do you think aquaponics should be incorporated into the classrooms? If so, what parts of it do you think should be taught?

What I like about aquaponics as a teaching tool is that it requires an interdisciplinary approach to problem solving. There are opportunities for all types of learning experiences – both from a theoretical and hands-on approach. People learn different ways and an aquaponics curriculum offers the opportunity to learn from these various approaches. To be successful in running an aquaponics system you have to know both aquaculture and having plant growing experience. You must also be able to integrate the two fields to run your system. There are also opportunities to use engineering skills to figure out flow rates, mass transfer and material science to design systems.

8) If you had any advice for someone entering the aquaponics industry what would it be?

I would say you are a lucky person! I think the field is getting more positive press and offers a way for people to grow their own food in a bio-secure way. There will be a demand for people for aquaponics skill sets. At the very least you will be able to run a system for your own personal use.


9) Do you believe it is more important to have aquaculture knowledge or hydroponics/botany to excel in aquaponics?

It is one of the strengths and weaknesses of aquaponics that you need to have both sets of knowledge to run the systems. That being said, one of the attractive features of aquaponics is that the fish and plant sides of the system complement and support one another in a positive way. Aquaponics systems are much more robust than either system in isolation.