GLWI DELIVERS PERCH TO GROWING POWER

Posted: April 30, 2008

Top: A few of the 10,000 yellow perch raised at the WATER Institute and released at Growing Power. Bottom: Two levels of plants and gravel sit atop a fish-filled trench in Growing Power's fish-farming system. Fish waste provides nutrients for the plants, and the plants clean the water for the fish.

WATER Institute researchers arrived earlier this month at Growing Power, an urban farm on Milwaukee's north side, with a special delivery: 10,000 young yellow perch.

Born and raised at the WATER Institute's Great Lakes Aquaculture Center, the three-month old fish will help test the waters, so to speak, of a new indoor fish-farming system that aims to prove itself functional as well as environmentally friendly and affordable.

Developed by Growing Power, the system features an 8,000-gallon trench built into the floor of a greenhouse and topped with two levels of edible plants, including watercress and dandelion greens. Pumps circulate water from the trench to the system's upper levels, where gravel filters out solids from fish waste and the plants absorb nutrients, using them to grow. The cleansed water then returns to the fish and the cycle begins again.

"It's a system that closely replicates nature," says Will Allen, Growing Power's CEO and founder. "In this instance there is a symbiotic relationship between the fish and the plants," he says, with waste from the fish providing nutrients for the plants, and the plants cleaning the water for the fish.

The materials to build the system cost around $1,500—about one tenth the amount of conventional commercial systems that use chemical processes to clean their water, says Richard Mueller, Growing Power's aquaponics manager.

A future for fish farming

The 10,000-fish trial is a follow-up to a successful smaller trial that last year produced 800 plate-size perch. Allen hopes Growing Power's approach to raising fish can one day be applied on a more widespread scale in rural Wisconsin, where fish farming—also known as aquaculture—could fill gaps left by a declining dairy farming industry and make use of vacant barn space.

WATER Institute scientist Fred Binkowski sees great potential for such systems in more populated areas as well. "There's a trend going on now where people are growing their own food, better food, and safer food," he says. "What we want to do is show that you can grow fish in an urban area, and put the food at the center of consumer demand." Urban fish farming can also cut shipping costs, fill vacant buildings, and create jobs in economically deprived communities.

There is also a more global reason to develop the area's rural and urban fish-farming industry. As the world's population grows, worldwide demand for seafood will exceed the sustainable supply from the wild—meaning fish farming will have to meet the remaining demand.

What's more, according to the U.S. Department of Agriculture, the United States imports more than 40 percent of its seafood—making the U.S. trade deficit for seafood the second largest in dollars, after petroleum, of any natural product. About $1 billion of this imported seafood is farm raised; meanwhile, the United States ranks only tenth in the world in farm-raised food fish production.

That leaves room for growth of the industry at home, a point well understood by WATER Institute researchers and Growing Power staff, as well as Leon Todd and Jon Bales, Milwaukee business partners who hope to launch an urban aquaculture center that will utilize the Growing Power model. Through collaborative efforts, the three groups hope to build a strong foundation for fish farming in the Milwaukee area and help establish the city as a national leader in the industry.

In the meantime, Binkowski and his staff will keep a close eye on the perch at Growing Power. Over the next year, they will perform weekly water quality tests and regularly monitor the survival and growth of the fish.

And if the system works successfully? "A year from now," says Binkowski, "these fish will probably be part of a Friday night fish fry."

–Jennifer Yauck