COLUMBIA — David Brune wants to grow saltwater shrimp in the middle of Missouri.
The MU agricultural systems management professor has spent months working on a greenhouse at Bradford Research Farm that will allow him to grow Pacific white shrimp year-round.
He wants to prove it’s possible and profitable to use sustainable technology to cultivate shrimp in mid-Missouri.
Instead of using a traditional pond, Brune is building a partitioned aquaculture system, growing shrimp in a greenhouse and using algae to provide oxygen through photosynthesis.
Brune said he hopes to apply more than two decades of his research to this project. Before coming to MU, he worked at Clemson University in South Carolina, where he developed the university's patented system.
Brune said the research reflects a bigger issue in modern aquaculture — sustainable fish and shellfish production. Most fish farmers still use traditional still-water ponds and are slow to adopt newer technologies.
He wants to find a way to persuade them to adopt his system and put fresh-market shrimp on the dining table in about three years.
Promoting sustainable aquaculture
The primary difference between the pond and Brune's system is a series of raceways. They are like lanes in a highway and allow the shrimp to grow at much higher densities than in conventional ponds.
Another key piece of his design is growing algae with the shrimp to provide oxygen and clean up the water.
Shrimp produce carbon dioxide and ammonia. When the substances reach a certain level, they become toxic, Brune said.
“During photosynthesis, algae removes the two things that are toxic and also produces oxygen,” he said. “It rejuvenates the water.”
In order to keep the algae growing, Brune puts water wheels in the raceways. The wheels, which look like paddle wheels on a steamboat, keep the water rolling and provide a better opportunity for algae to get sunlight.
“The algae grow four to five times faster than in a still-water pond,” Brune said.
If the algae population becomes excessive, however, it can harm the shrimp population. This is one reason fish farmers dislike algal blooms in fish ponds, Brune said. Large quantities of algae can increase the need to aerate the pond.
During his research at Clemson, Brune developed the technique of using tilapia co-cultures to control the algae population.
Having tilapia — a freshwater fish — in the system selectively removes the type of algae that isn't compatible with aquaculture species. Tilapia control algae density and also reduce the occurrence of zooplankton blooms that can “crash” the system.
After several years of experimenting with this process, Brune was able to achieve a huge leap in fish production.
“When we started doing this, (the farmers) were producing 5,000 pounds of fish per acre," Brune said. "After a few years, we were able to reach 20,000 pounds per acre.”
The facility at MU
The greenhouse Brune is working on at Bradford Research Farm is built around the same concept.
The facility takes up one-fifteenth of an acre, about the size of a tennis court. It is divided into two identical sections for experimentation and educational purposes.
Each section has two shrimp raceways that are 3 feet deep, a tank of tilapia, a water wheel and two tanks providing additional water treatment.
Brune will buy dried sea salt to make the salt water that fills the raceways. He said he will grow about 30 times the density of a still-water pond.
The tilapia tanks are placed next to the raceways, and Brune will keep the fish in plastic or fabric nets.
The two back-up tanks are needed, Brune said, because Missouri’s winter is colder and cloudier than in South Carolina. The reduced sunlight and temperature could kill the algae, which has prompted him to devise a back-up system to clean up the water.
The back-up tanks will contain bacteria that can break down the excess ammonia produced by the shrimp, eventually converting it to nitrogen gas.
Also, because of the colder weather, the water must be heated during the winter.
“We can’t afford to buy heat, so we are going to put a biomass generator next to the shrimp culture facility,” Brune said.
The generator will burn wood or grass and produce electricity. Brune hopes to sell the electricity to the city grid and use the waste heat produced in the process to warm the shrimp.
“Usually when burning wood, it produces a kilowatt of electricity and two kilowatts of heat,” he said. “Most places don’t even use it — most places throw that away — but we are going to use that to heat the water.”
Is this feasible for the farmers?
Internationally, the shrimp-farming business is dominated by Asian countries.
According to the 2008 fishery and aquaculture statistics from the Food and Agriculture Organization of the United Nations, the total Pacific white shrimp (also known as whiteleg shrimp) production was about *2.26 million metric tons that year.
The United States contributed 1,932 metric tons, less than 0.1 percent of the total.
Mainland China produced 1.06 million metric tons, about 47 percent, and Thailand produced 498,800 metric tons, about 22 percent.
In Asia, the labor and environmental costs are significant lower, Brune said. The farmers are less regulated and can use chemicals to control diseases.
Brune said he stresses high productivity as one advantage of using his system.
When he was at Clemson, Brune worked with farmers interested in installing his system, but persuading them to try it was a long and difficult process, he said.
“I worked there for 20 years, and for the first 10, most fish farmers wouldn’t talk to me,” he said. “Many didn't want to install the system, and they didn't want their neighbors to install the system because it could lead to potential competition.”
Money is at the heart of the issue, Brune said. Installing a new system costs roughly $25,000 per acre, and not every farmer has those resources, so they prefer to stick to their old ways.
Craig Tucker, a former colleague of Brune’s who now works at Mississippi State University, agreed. He made a commercial version of Brune’s design, naming it the “split-pond system.” Instead of building a greenhouse, Tucker built levees in existing ponds to create the raceways, a design some farmers later adopted.
“It’s the simplified version of what David created,” Tucker said.
With the split-pond system, a farmer can expect to produce 15,000 to 21,000 pounds of fish per acre per year, which is three or four times more production than in an ordinary still-water pond, Tucker said.
Yet, producing more fish is not a big deal, he said. The real trick is to do it and make money.
“It appears that this can be a profitable way to make fish," Tucker said. "You can control over the environment; the survival is good.”
Tucker said no economic analysis has been done to explore the profitability of a split-pond system.
“You have to determine long-term construction costs that can be fairly sizable, so you’ve got to in the long term to make enough money. That’s the key we know right now,” he said.
Tucker built his first commercial system in 2009. Two years later, there were a couple hundred acres of split ponds in Mississippi, he said, demonstrating eventual acceptance of his idea.
“(The farmers) think it’s economically justified, even though we haven’t done a formal study on that yet,” he said.
“Frankly, no one knows,” Tucker said.
Paul Smith, owner of Show-Me Shrimp Farm in Dixon, said he’s heard of saltwater shrimp farming, but it’s unlikely he’ll convert to that system.
“It’s easier for the normal farm to raise farm prawns than growing saltwater shrimp,” he said. Smith said he has been growing in-pond prawns for 10 years, and his farm produces between 200 to 600 pounds of prawns per year, depending on the weather.
He said growing saltwater shrimp is expensive and requires assembling a new facility. Not every farmer has the ability to do so.
The trick is to get started
Brune recognizes that farmers are used to growing freshwater prawns in Missouri, and it won't be easy to persuade them to change.
According to the 2005 census of aquaculture, there are two farms in Missouri that raised freshwater prawns, and one farm in Missouri raised saltwater shrimp.
“The only way to know whether you can do this is to build the system and grow the shrimp,” he said. “First thing people want when they come in with money is 10,000 pounds of shrimp.”
This is why Brune hopes to determine whether the greenhouse is a feasible option.
“I hope to expand to tens of acres within three years, ” he said. “That means success and proving profitability.”
Brune said shrimp production could be significantly more profitable than corn or soy beans, which only make about a few hundred dollars an acre. But with saltwater shrimp, if successful, he’s looking at about $100,000 to $300,000 cash flow per acre per year.
The plan is to provide shrimp samples when investors come to see the facility, Brune said.
He intends the facility to be sustainably dependent on biomass energy, but to be profitable, the biomass-generated electricity will need to sell at a higher rate than fossil-fuel generated electricity, and the fresh shrimp will have to sell in local market at prices greater than frozen shrimp from Asia, he said.
He hopes he can charge a premium price of $4 to $5 a pound for what he calls a “higher-quality, locally grown product.”
“If people are unwilling to pay a premium price, we’re in trouble,” he said.
Tim Reinbott, Bradford Research Farm's superintendent, said he’s quite excited about what Brune is doing. He provided the site and has helped with supplies and equipment.
“There can be workshops, opportunities to talk about what he’s doing, to help the people know about it and understand it,” Reinbott said.
That’s exactly what Brune plans to do.
“That’s the name of the game: Get something built and then find the money,” he said. “Really, the trick is to have something on the ground to show people.”