An increasing number of farmers are turning to aquaculture to ramp up production of fresh produce and fish year-round —even on tiny urban lots.
Photos courtesy of Christopher Hartleb
Imagine rows of lettuce and herbs growing on a small city lot, their bright green leaves stretching toward the sun. It’s an urban farmer’s dream and a local food fanatic’s fantasy.
Only these rows aren’t planted in the soil. They’re floating atop a large tank of tilapia. And they aren’t growing outside in the bright summer sun. They’re growing in a greenhouse in the winter — in Wisconsin.
Not that long ago, this scene would have sounded like something out of a science fiction novel. But today in an increasing number of cities, it’s a reality thanks to aquaponics.
Rooted in History
Aquaponics combines aquaculture (fish farming) with hydroponics (the cultivation of plants in water.) Fish are raised and fed in tanks, then the nutrient-rich fish wastewater is absorbed by plants floating on rafts, with their roots stretching down into the water. Sometimes the plants are in the same tank as the fish; other times they’re in a separate tank with the water pumped between the two. Once the plants absorb the nutrients from the fish tank effluent, the cleaner water returns to the fish and the cycle begins again. If the system operates correctly, there’s no need for the addition of outside nutrients or fertilizers — and very little water is lost in the process.
Although this type of science-based aquaponic system has only taken off in the past 30 years, since its development by researchers at the University of the Virgin Islands, the principles of integrating agriculture with aquaculture have been around for a long time.
“People have found drawings of similar systems in Mayan and Egyptian ruins,” says Chris Hartleb, professor of fisheries biology and co-director of the Northern Aquaculture Demonstration Facility at University of Wisconsin-Stevens Point.
Aquaponics is one variation on integrated agriculture aquaculture systems (IAAS), in which aquaculture is combined with livestock and crop farming for more efficient use of resources and diversification of crops. IAAS has long been practiced in Asia by subsistence farmers, and more recently in places ranging from Israel to Australia as a means of achieving more economically viable and environmentally sustainable food production.
One of the perks of aquaponics over the integrated systems in use in many other countries around the world today is that it can be implemented almost anywhere and requires minimal space.
“The concept of urban agriculture is really catching on,” says Gene Giacomelli, professor of agriculture and biosystems engineering and director of the Controlled Environment Agriculture Center at the University of Arizona. “These systems are intriguing because they can be done on a small scale in a highly urbanized area.”
And in many ways it’s easier on the environment, although electrical power is required for intensive production. “This type of system doesn’t damage the environment as much by keeping nutrients out of waterways and drinking water, reducing or eliminating the need for pesticides or synthetic chemicals, and reducing water use,” Gene explains.
In recent years, aquaponics has been popularized by Growing Power, a Milwaukee-based organization that trains people on how to start urban farms and aquaponics operations in order to scale up development of community food systems across the country.
Growing Power inspired Lloyd Minick and Michael Hanan, co-founders of Ten Acre Organics in Austin, Texas, to jump into urban agriculture after college. “We started talking about the possibility of a business to address some of the really big challenges we face — business as a solution to climate change and lack of access to healthy food,” Michael says, now chief marketing and operations officer for Ten Acre Organics. “Learning about Growing Power kind of catalyzed things. We knew we wanted to start an aquaponics farm at that point.”
Lloyd and Michael started learning about aquaponics and researching sustainable agriculture. Michael worked at organic farms and nurseries in Austin and studied with the team of researchers at the University of the Virgin Islands. In 2012, they began construction of their microfarm on a lot in east Austin, armed with $17,000 raised through a Kickstarter campaign.
“It’s a prototype of the integrated approach to agriculture that eventually we’d like to roll out on 10 acres. It’s kind of our proving grounds,” Michael says. On a one-fifth of an acre residential lot, Michael and Lloyd have 3,000 square feet of row crops, 1,000 square feet of aquaponics, 23 chickens, a beehive, mushrooms, and a composting site where they compost waste from the farm and local restaurants.
“What we’re trying to do is look at the farm as an ecosystem and tie together all these different forms of food production so that what would normally become a waste stream becomes another method of input,” Michael explains.
“Aquaponics is the perfect example of a symbiotic relationship in ecosystems, where no resource goes to waste,” he adds. “We get two products — fish as well as delicious and fresh vegetables — in a very compact and densely productive system, so it works perfectly for us in our urban setting and given our commitment to sustainability.”
The guys at Ten Acre Organics raise tilapia, which thrive in warm temperatures, and grow greens and herbs through their aquaponic system, then supplement that by growing other crops in their fields. The farm sells directly to restaurants and just started delivering its community supported agriculture shares at the beginning of June.
To operate optimally in Texas, Ten Acre Organics had to construct a greenhouse to shade the plants in summer and protect them in winter. “The aquaponic systems are rather expensive to construct, but that is justified by the fact that they’re so densely productive,” Michael says.
In most of the United States, aquaponic systems function best in greenhouses, which provide year-round production and keep out pests and airborne diseases. The key is to raise fish and plants that thrive at compatible temperatures, are suitable to the local environment, and are marketable. That’s why so many operations raise tilapia.
“Tilapia right now are very popular in restaurants and supermarkets, so there’s a good market to sell to,” Chris says. In addition, tilapia are a tolerant fish, so they’re good for beginners just figuring out aquaponics.
The scalability of aquaponic systems is another plus. “Farmers can start off small until they understand the performance of their system, then scale up to a large commercial system,” Chris says. That’s why Lloyd and Michael are running their microfarm before investing the time and funds needed to start production on a 10-acre site.
“Science-based commercial aquaponics is definitely on the rise,” Chris says. Enrollment in an accredited aquaponics course at the University of Wisconsin-Stevens Point doubled from 2012 to 2013, and the university hosted the first International Aquaponics Conference in June.
Chris encourages people interested in aquaponics to learn as much as they can and start small.
“It’s not trivial putting together the knowledge on growing fish and the knowledge on growing plants,” Gene adds. “It’s twice the work, but potentially it’s twice the output.”
With many Americans’ interested in where their food comes from and how it’s produced, the benefits of aquaponics extend beyond productivity. That’s something the guys at Ten Acre Organics are experiencing first-hand.
“There are tons of people looking to connect with where their food comes from, connect with this agricultural history we have that’s been largely forgotten in the last 50 to 100 years,” Michael says. “People are trying to connect with nature in general and with one another. We’re serving the community and the community is excited to help propel what we’re doing.”