Biology major faces challenges to build aquaponics system at USD

A new, integrated way to grow vegetables and harvest fish at the same time may be coming to Vermillion.

Parker Messerli, a fourth-year biology major, is trying to find a place on campus or in Vermillion to set up an aquaponics system, which takes aquarium water, sullied with fish waste and nutrients, and uses it to water vegetables. The vegetables use the fish waste as fertilizer, filtering it out. The water then returns to the aquarium without harmful fish waste and filled with healthy nutrients from the plants.

“Aquaponics is the marriage between aquaculture, which is raising fish, and traditional greenhouse growing (of plants),” Messerli said.”What it’s doing is basically creating an ecosystem between the fish and the plants — the plants filter out what the fish don’t want, and that keeps the water clear so they can thrive in grow.”

While there are several types of aquaponics systems that can be built, Messerli’s system would pipe the aquarium water out of the aquarium and into a bed of growing vegetables, then back to the aquarium. 

“You have a tubing in the fish tank to the grow bed, where you push the water through that and allow the plants to filter out waste and other products that they can use, that the fish perceive as toxic,” Messerli said.

While the fish still have to be fed, the nutrients provided by the plants are still good for their health, and having the plants doing the filtering work eliminates the need for water filtration. The plants are able to absorb enough nutrition from the fish waste water to reduce their need for fertilizers.

The system would cost approximately $200, and Messerli’s current vision of the system would be, roughly, a 20-gallon tank with about five fish and about a 2′ x 4′ area for plant growth. In theory, a well-thought out aquaponics system should be relatively low-maintenance, Messerli said.

“Because it’s set up like an ecosystem, it encourages bacteria growth, which basically takes all the decomposing matter from the water and breaks it down for the plants to use,” Messerli said. “So generally if you set it up with some forethought, there’s not going to be very many problems.”

Messerli said that his system might use decorative rather than edible fish species right away as he tries to master the technique, though he will grow vegetables. Eventually, he would like to include species of edible fish that are known to thrive in an aquaponics environment, such as tilapia.

There are roadblocks in Messerli’s way besides the technical challenge of setting up an aquaponics system — the biology department turned him down when he asked for their help in setting up the system, as there was no space for it. There are also cumbersome rules surrounding live animals kept in an experimental setting — they must be housed in a secure setting, under the supervision of the medical school.

Thus, Messerli has gotten creative in his search for a home for his aquaponics system. He is considering Heikes Family Farm north of Vermillion as a possible location, or a local church. 

In planning for the aquaponics system, Messerli has been “bouncing ideas off of” Jeff Wesner, a sustainability professor. Wesner said he appreciates Messerli’s tenacity in trying to launch the aquaponics system in spite of the challenges he faces in launching the system.

“I always like it when students have an idea to improve the university somehow, and a lot of students have those ideas and then you say, ‘OK, here are the barriers to getting that done,’ and you list 1,000 things,” Wesner said. “And Parker’s not really deterred by that, he’s trying to find space for it, he’s really motivated to get it done. And to me, here’s a student that’s spending time doing something that’s going to be a cool project for the university — why not support something like that?”

Wesner also said the aquaponics system would be a good learning opportunity when discussing fish ecology in class.

“We can talk all day about fish in a river, but if I can go show someone fish that are feeding in a tank, it’s much easier to talk about those fish, talk about their nutrients, talk about nutrient flow through an ecosystem with something like that,” Wesner said. “It’s a perfect teaching tool. And of course it also produces harvestable food, so that also is a perfect teaching tool of ways to make our food system more efficient.”

Ideally, Messerli would like to have much of the legwork for the aquaponics system completed by spring.

“I’ll be here for another year, but I would like to have it going at least a semester before I leave,” Messerli said.