Behind the building, a biodiesel generator and waste vegetable oil boiler, both dormant during the summer months, attest to the aquaponic system's thirst for energy—the pumps, filters and bioreactor run year-round at a sometimes deafening whir, and the winter brings a need to heat the tanks and power overhead lights, as well.
These demands make it tough to compete with foreign and industrial-scale aquaculturists on the metrics of price and size alone. (Luckily, the fast-growing vegetable crops are the primary moneymaker.) Cabbage Hill's customers are mainly local restaurants and markets that prize what Ferry refers to as "farm-to-table" relationships. "These systems are fairly expensive," Rakocy notes. "So you have to raise really high-value crops and look for niche markets."
Rakocy has sought to drive down the price of aquaponics by developing projects that run on waste energy. UVI was part of a consortium that, with the help of a $150,000 grant from the U.S. Environmental Protection Agency in 2001, built a landfill gas–powered aquaponic facility at Rutgers University's EcoComplex, a research center at the Burlington County, N.J., landfill. "In the future," he says, "I could see aquaponics setups ringing landfills," mining their waste gas to produce food.
Even in its present energy-hungry state, Rakocy points out, aquaponics has an advantage in the preservation of another precious resource: water. Much of the irrigation water in traditional agriculture runs off the soil or evaporates before it reaches the roots. In a recirculating aquaponic setup, by contrast, "the plants just take what they need, and the rest stays in the system and goes back to the fish," he says. In fact, the UVI system is so efficient that its occasional losses are entirely replenished by a rainwater catchment system, Rakocy adds.
Martin Schreibman, a biologist at Brooklyn College in New York City and an advocate for urban aquaculture, concedes that aquaponics poses myriad challenges but, like Rakocy, he sees the tank as half full. "Every revolution had its own problems: the Industrial Revolution, the Green Revolution, the agricultural revolution," he says. "Now the blue revolution that people are talking about, sure it has problems, but you can get around them. I think these are problems that are resolvable."
In fact, Schreibman adds, adopting aquaponics near population centers could present solutions to other intractable problems. "Natural fish stocks are all depleted, we have problems with tainted food coming in from abroad, we have unemployment here, we have a bad economy," he says. "This kind of urban aquaculture and urban aquaponics addresses these questions."
Schreibman notes that criticism of the energy requirements for aquaponics plays down "the energy that's used boating something from China or flying it up from Ecuador," two of the primary importers of seafood into the U.S. "So it's a trade-off. We're not trucking it miles."
As fuel prices for imports rise and more and more environmental issues linked to food production come to light, the level of interest in aquaponics is "increasing astronomically," Rakocy says. He leads a short course at UVI on aquaponic methods, for which he says attendance has more than doubled from 33 to 73 students in the past three years. "This year we had to reject a bunch of people," Rakocy says. "I've been getting so many inquiries saying, 'Put me down on the waiting list for next year.'"