Tilapia, lettuce co-exist happily in LaPorte

By Cherry Sokoloski
North Forty News

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In a little corner of LaPorte, a sustainable ag operation is quietly ramping up, getting ready for large-scale production. "Eat local" folks are already enjoying ultra-fresh salads from the LaPorte facility. As soon as processing is available, they will be able to dine on fresh tilapia from the same source.

Quatrix Aquaponics is an unusual agricultural operation that produces both fresh produce and tilapia. The business, owned by Matthew Westenhaver, consists of a large greenhouse and an attached steel fish house, all located on County Road 54G in LaPorte.

After three years of building and developing the ecosystem, Westenhaver started selling produce from the greenhouse this past winter. "We were the only ones selling fresh produce at the winter farmers markets," he said. It was a big hit with customers, and he plans to be at several markets this summer.

Westenhaver also harvested the first tilapia recently, and his family has been experimenting with different ways to cook the fish. Whether it's smoked, broiled with butter, blackened or baked, he reports that it's delicious.

"People are nipping at our heels for the fish," said Westenhaver, and he hopes to be able to satisfy that demand soon.

The term "aquaponics" comes from aquaculture, or fish farming; and hydroponics, a way to grow vegetables without soil. Aquaponics was developed primarily as a way to conserve water, always a plus in arid Colorado. According to Westenhaver, the system uses 80 percent less water than conventional farming, since the same water is continuously recycled.

Aquaponics relies on a symbiotic ecosystem, in which fish provide a natural fertilizer for the plants and the plants, in turn, filter the water so it can be returned to the fish tanks. It's an all-natural system, Westenhaver explained, with no pesticides, chemical fertilizers or herbicides added. Also, there's little waste.

Westenhaver buys tilapia fingerlings from an outlet in Louisiana. They're raised in four large tanks, each holding about 1,000 fish, and it takes about 10 months to grow them to market size. Westenhaver figures he could harvest about 11,000 pounds of tilapia a year.

After water leaves the fish tanks, filters get rid of solid waste and methane gas while beneficial bacteria convert the ammonia to nitrogen. Water is then piped to long troughs in the greenhouse, the hydroponics part of the operation, where plants grow on a floating "conveyer belt" of Styrofoam, their roots dangling in the water.

The water system is gravity-fed, requiring only a 2-horsepower pump to keep things moving.

Plants, which currently include a variety of lettuces, basil, cabbage and tomatoes, thrive on the nutrient-rich water from the fish tanks. The water includes nitrogen, potassium and phosphorus, so the only nutrient Westenhaver has to add is iron.

Westenhaver is especially proud of the quality of his products. When a person buys frozen tilapia fillets in the grocery store, he noted, there's no way to know about the water in which the fish were raised. His water quality, on the other hand, is tested regularly and is 97 percent waste-free after the plants finish their filtering.

The Quatrix tilapia, Westenhaver said, are "far superior to anything farm-raised."

As for produce, the nutrient content of Quatrix lettuce is much higher than that of greens that have been trucked in from other states, Westenhaver said. And, less transportation means a smaller carbon footprint.

Aquaponics has been successfully used in several countries, both in tropical climes and the cold north country. In Alberta, Canada, there is a five-mile-long aquaponics operation. The system is also used in the Virgin Islands, and that's where Westenhaver received his aquaponics training.

Unlike the Virgin Islands farmers, Westenhaver has to deal with a four-season climate. While designing his aquaponics system, he was determined to find an efficient, earth-friendly system for heating the greenhouse.

He built a subterranean heating system, consisting of corrugated flexible tubing covered with 800 tons of crushed rock. The tubes come to the surface inside the greenhouse, allowing for the exchange of warm and cool air. During the day, solar-produced heat is stored in the rock. Circulating fans bring the warm air into the greenhouse at night.

Westenhaver and his parents, Ken and Marcia, tested out the heating system by building a much smaller version under their LaPorte sunroom.

Some conventional heating and cooling systems are required to supplement the sun's rays. Tilapia is a tropical fish requiring warm water, and a swimming pool heater keeps the fish happy. For summer cooling, the greenhouse has swamp coolers and additional fans.

Quatrix is a two-man operation at present, with business operations handled by Josh Best. Westenhaver's parents also fill in where needed.

"These are the farms of tomorrow," said the optimistic Quatrix owner. With little land, not much water and a symbiotic system, aquaponics operations can grow fish and produce to market size very quickly. At the same time, they provide a food source that's nutritious and local.

Westenhaver is now contacting local restaurants about his products, so it's possible that eco-conscious consumers will see Quatrix fish and veggies at their favorite dining places soon.