Articles and Information

"Future AquaFarms, Nova Scotia, Canada"

by Rebecca Nelson

Dave Roberts and Carla MacQuarrie, co-workers at Canadian Fishery Consultants Ltd. in Nova Scotia, traveled worldwide assisting people who wished to establish fish farms or make existing fish farms profitable. Before Carla began working for CFCL, she studied Environmental Engineering at the Technical University of Nova Scotia and, prior to Dave’s 12 years working for Canadian Fishery Consultants Ltd., he studied aquaculture, biology and environmental studies. Although both Dave and Carla had extensive experience with cold-water fish culture, they were intrigued with Tilapia, a very hardy and fast-growing warm water species. Following their involvement in a feasibility project in 1996 which studied utilization of waste heat for recirculating Tilapia culture, their mutual interest and training in aquaculture led them to discussions of a zero-waste, highly productive food production system…aquaponics. Further research and continued discussions eventually led to these two planning to design, build and run an aquaponic business.

Each had studied and worked with Tilapia in their jobs as consultants but growing plants in soilless culture and the design of a fully integrated aquaponics system was a new challenge. To get started, they ordered a how-to manual from S & S AquaFarms. This book is based on the working model S & S has developed for a small-farm aquaponic system with total utilization of fish waste and gravel-filled grow beds. With the manual as a guide, Dave and Carla proceeded to learn the basics and, later, to figure out critical pieces of the aquaponic puzzle. Information on stocking densities of plants and fish and advanced design issues were at the top of the list of areas that required research. With additional research and study, they plodded forward.

Dave and Carla incorporated Future Aqua Farms, Ltd. (FAFL) in 1998 and, after much research but never having seen an aquaponic system in action, began construction of their pilot-scale 2,880 sq. ft. greenhouse in May of 1999. "We learned a lot building the greenhouse. It was quite an endeavor since neither of us had done anything like that before," Dave explains. Based on the S & S model and design ideas of their own, the growing system was built. By June the grow beds were planted and in July the fish tanks were stocked. Currently, Dave is still working full time with CFCL and Carla, after receiving a scholarship to study in the area of aquaponics, is working on her Masters. Her thesis subject involves their aquaponic system and operation so it gives her more time to be there. FAFL relies on the valuable experience of two employees, Joy Pye-MacSwain and Peter Lenihan, who have been involved with the operation since inception to help in the greenhouse with the day-to-day operation as well as the involvement of many family and friends. Dave’s wife, Joanne, is responsible for selling 80% of the product at the market each week.

The greenhouse at Future Aqua Farms is 30’ x 96’, housing 6 aquaponic nodes, each node containing a 1,000 gallon fish tank and 6 gravel-filled grow beds, each approximately 4’ x 8’ x 1’ deep. The growbeds are flooded with water pumped directly from the fish tanks with no separation of solids or pre-filtering. The greenhouse was purchased from a local supplier, Halifax Seed, and the tanks and grow-beds were purchased from Poly-tank. All of the other components were purchased from a variety of sources that Dave and Carla had sourced locally. The six nodes provide about 1,056 sq. ft. growing area and the tanks, walkways and other equipment take up the remaining space.

Environmental control equipment in the greenhouse includes a 147,000 BTU oil-fired furnace and tank water heaters. A recently implemented computer program assists FAFL in monitoring all daily environmental conditions in the greenhouse and fish tanks. They have a phone-dialing alarm for temperature, water flow and the computer system. Temperature probes in each tank will activate the alarm if the temperature is too hot or too cold. "We also have a flow detection switch that comes from the return sump and goes back to the tank so if either the supply pump or the return pump breaks, it will alarm us. If, after ½ hour there is no flow detected, it will call us at three numbers," Dave explains.

Tilapia are stocked in the fish tanks and initially the plant beds were started with mostly tomatoes, complemented by lettuce and basil. Dave and Carla quickly found insects, specifically whitefly, to be a threat to the tomatoes in addition to a lack of sufficient sunlight in the fall and winter which weakened the plants. The problems encountered with the tomatoes led Dave and Carla to experiment with cucumbers, peppers and a variety of culinary herbs including basil, parsley, arugula, chives and watercress. The herbs, cucumbers and peppers have all done quite well. Carla explains "We occasionally have an outburst of aphids so we bring in some ladybugs and try to achieve a balance."

On balancing the system, Carla shares, "We do have to adjust our pH and we use agricultural lime in addition to some micro nutrients that we are adding. We also use potassium bicarbonate to help buffer the system because we have very soft water here with no alkalinity and a low pH that requires adjustment. The potassium bicarbonate helps because it buffers the system and also supplies additional potassium for the plants." The water used in the greenhouse is directly from a well with no filtration.

FAFL is just starting to harvest its fish which are sold whole at a weekly Farmer’s Market. The herbs, cucumbers and peppers, sold as organic produce, are mostly sold there also. Carla comments, "We sell out of some products by 9:00 in the morning. People just love to get our stuff. It is definitely a good position to be in." Future Aqua Farms, Ltd. also sells some of their produce through local grocery stores. To help build awareness of aquaponics and a loyal customer base, a cute logo with a fish eating a tomato is placed on all of the produce before it goes to market.

Experimenting with NFT (Nutrient Film Technique), they’ve found that the channels work very well for some of the plants. There are no separate bio-filters in the system and the water that flows through the NFT channels first passes through the gravel beds where solids are removed and bio-filtration takes place.

The gang at FAFL has observed some complications with the current design of the grow beds. One drawback is that they need to pump the water twice…once out of the tank into the grow bed and then back into the tank from the grow-bed…doubling the chance for pump failure and the cost of electricity dedicated to moving water. Carla adds, "We are looking at some different designs to change that and also will add more NFT channels as opposed to the beds filled with gravel because of the complications of having that mass of rock, not only weight-wise but also in trying to keep it clean. That is where our bacteria live and it is a lot of surface area to control and keep optimal conditions for the bacteria to live." Dave and Carla also see an opportunity to utilize the vertical space in the greenhouse with NFT channels built in an A-frame design.

Modifications that FAFL has made over the last year include adding timers to the sump so the grow-beds could be fed on a timed basis and adding a one h.p. blower for aeration to ensure adequate O2 levels 24 hours a day. Dave comments, " We are hoping at this time next year to be expanding into a newer, larger greenhouse and in that system we will probably have the fish less integrated which will give us more control over both systems." They are also considering going to a system where all of the solids are removed and then composted or used on outdoor soil crops.

Future Aqua Farms, Ltd. has started a brood stock program with fish they imported from Thailand. Now, the tanks are filled with fish they acquired last July and September but, once they are up and running with the hatchery, they plan to stagger the size of fish in each tank in an attempt to have more frequent harvests. Carla shares, "We want to come up with a hatchery design that is efficient enough to be introduced to any small aquaponic facility so that small-scale farms don’t have to depend on a tilapia breeder."

On her Master’s thesis, Carla explains, "I’m doing my Masters thesis on developing a model for an aquaponics system because I don’t feel the balances in an aquaponic system are understood well enough. It is all explained by science and there should be 

an exact uptake curve of the plants and an exact output curve of the fish, the relationship of the food and all of the different balances that are going on. PH, C02 production and O2 depletion each interact with each other and I want to develop a very detailed model that incorporates all of the factors involved. At some point down the road I would like someone to be able to use my model, to be able to say, ‘I am putting in this many fish at this size with this particular growing bed.’ My model would tell them how many plants they should plant."

Carla feels the biggest hurdle a potential aquaponic grower faces is education because it is essential that a grower understand the fundamentals of aquaculture including ammonia levels, nitrification, pH, alkalinity and the balance between all of these factors. In the future Carla believes aquaponics will become more refined with less trial-and-error. She also feels there is a great potential for aquaponics on family farms.

Dave comments, "I would say the area that needs the most research in aquaponics would be the nutrients available to the plants and supplementing what’s missing. We’ve had to add certain elements as the crops grew. Most of the literature and information available is more related to hydroponic or soil growing conditions. For instance, right now we are questioning, ‘how much nitrate does a certain biomass of plant take up’ and it is an ever-changing question. We are trying to see, based on the amount of feed in the system, how much square footage of plants can you support. Also, I would like to see more economic studies done on various growing systems."

With their initial investment of just under $100,000 for this pilot-project and base operating costs, Future Aqua Farms, Ltd. needs to take in about $3/sq. ft./month to break even. Right now they are experimenting with 7 or 8 different crops, with basil proving the most profitable. Under ideal conditions, if this system was planted with just basil, Dave figures it would gross about $8-9/sq. ft./month. Dave has calculated the cost of raising the Tilapia at about $2/lb. and they are selling at the Farmers Market whole for $4.50/lb.

Dave shares, "Our next greenhouse will be twice the size, 6000 sq. ft. and I’ve done the projections on the economics of that. With redesigning it and making it more efficient than this one, we probably should be able to gross $250,000-$300,000 between the two greenhouses."

With a desire to help refine this new technology and a commitment to making their aquaponic enterprise successful, Future Aqua Farms, Ltd. is off to an exciting start. This dedicated team is forging ahead, facing new challenges every day. What has and will continue to make them successful is their experience in aquaculture, their scientific approach and their willingness to ask questions and experiment with new ideas. I look forward to following their progress for many years to come.