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Aquaculture springs up in West Virginia.

Cool, clear water - an element essential to life. About 1,200 gallons a minute gush from a mountain spring just a little south of Shepherdstown, West Virginia. Located on the grounds of the Freshwater Institute, Morgan's Spring supplies the life source for new, experimental fish farming projects.

"Our natural supplies of fish are at risk. Demand is increasing and ocean catch decreasing," says Lewis W. Smith. "We now import over 40 percent of all edible fish and shellfish products. One answer to lowering our imports yet still meeting consumers' demands is to step up our own efforts to produce more farm-raised fish."

ARS national program leader for animal nutrition, Smith also oversees agency involvement in aquaculture research.

For years, ARS has been involved in catfish research related to static water systems, either ponds or raceways. But this newest venture, begun at Morgan's Spring, is a step into uncharted territory for ARS - raising rainbow trout (and eventually other species) in recirculated, fresh spring water.

Researchers at the Freshwater Institute near Shepherdstown are raising rainbow trout two ways: in a large, high-tech, high-density, indoor tank system monitored by computers; and in a smaller, low-tech, simple, outdoor tank system run by gravity.

ARS scientists are evaluating the use of fish waste from the indoor tank system as fertilizer for high-value agricultural crops.

Although wastewater from fish farming isn't toxic to the environment, it can pollute streams by adding excess nutrients, like nitrogen, phosphorus, and organic matter.

"These nutrients increase algae's growth m water. Since die action of microbes decomposing the algae requires oxygen, this can lead to oxygen depletion, which can kill fish in affected waters," explains Paul Adler.

Adler is a horticulturist based at the ARS Appalachian Fruit Research Station in Kearneysville, West Virginia. He is working on a research project that would allow the aquaculture industry to expand without the risk of water pollution.

"To protect the environment, we've developed an economical and effective strategy to purify wastewater from the project at Shepherdstown," Adler says. "In nature, there is no waste. The byproducts of one organism are the inputs of another. We're just trying to emulate nature by engineering a system that doesn't generate waste."

To do so, he is using fruit, vegetable, and ornamental crops not only to clean the water, but also to provide a profit to growers.

"Of course, it'll cost money for growers to build greenhouses for these plants," Adler says. "However, conventional wastewater treatment technology is just as costly, and it lacks the benefit of bringing in additional income."

Another way Adler removes nutrients from wastewater is with periphytic algae. These algae are commonly seen as a green, slimy covering on underwater rocks in streams and lakes.

"These algae remove all the waste from water pumped from the rainbow trout tanks. allowing us to return wastewater to the stream in its original pristine condition," he says. And Adler is exploring yet another idea - constructed wetlands to treat the waste.

"Construction costs are only about 10 to 50 percent of those required for conventional waste treatment plants," he says.

Although an artificial wetland would not generate income by producing a high-value crop, it would reduce costs of treating the waste by conventional methods. Furthermore, it wouldn't require the horticultural expertise needed to maintain greenhouses. Another advantage of a wetland, Adler says, is that it creates a habitat for wildlife.

Native plants in a constructed wetland would take up excess nutrients from the fish wastewater. And the plants would do more than just absorb nutrients. According to Adler, they also secrete enzymes that can digest excess nutrients, making them absorbable by the water.

Engaging High-tech Sophistication

The wastewater for Adler's research in greenhouses built at Shepherdstown comes from the high-density fish farming system installed there.

ARS cosponsors this research with the Freshwater Institute, founded by Robert E. Putz and now directed by Larry Selzer. The institute is part of the Conservation Fund, a nonprofit organization that works with private and public partners to protect and conserve land and water resources.

"Our high-tech recirculating system uses less water, controls the light that expands feeding time, and eliminates predators," says John M. Heinen, scientific project leader. Subcontracted by the Freshwater Institute, Heinen works for Zeigler Brothers, a private aquaculture company headquartered in Pennsylvania.

"We harvest trout from this system about every 2 weeks. It takes about 200 to 220 days from stock to harvest," says Joseph Hankins, Freshwater Institute's director for aquaculture programs.

According to Hankins, in the first year of operation, success was phenomenal.

"Loss from fish mortality was very low. In fact, we harvested better than 95 percent of what we stocked," Hankins says. A second-year trial is now under way. Results so far look even better.

This Is Where It Happens

From a small room at the Institute, a sophisticated computer system monitors the entire project. Information from multistage oxygenators, microscreen particulate filters, and fluidizedbed biological filters constantly feeds into the computer that evaluates environmental conditions for the fish. These include waterflow, pH level, dissolved oxygen, and temperature.

Four identical fiberglass tanks, each holding 2,500 gallons of water, support several sizes of rainbow trout. Each tank holds about 5,000 fish - so many fish that the water looks murky and stays in constant motion.

But it's not just the movement of the fish that makes the water churn.

"Water enters through jet ports at the bottom of the tanks, which causes continual circulation in a crossflow fashion. This creates good velocity and maintains uniform water quality," Hankins explains.

Fish need lots of oxygen. "Through oxygenators, our system increases the dissolved oxygen levels two to three times above that of the water originally in the tank," Hankins says.

Because of the high density of fish and the water velocity, little fish waste settles in the tank. Instead, the water action propels it through outlets just above the tank bottom.

As water leaves the tank, it passes through a microscreen particulate filter that removes fecal matter. The water then flows into a biofilter where bacteria change the ammonia given off by the fish into nitrate, which is harmless to fish.

Since about 90 percent of the water in the tanks is recirculated, only 10 percent comes in directly from the spring. This keeps tank temperatures at about 55 [degrees] F to 60 [degrees] F.

"Since we have so many fish in the tanks, we need to strip from the water some of the excess carbon dioxide they generate," Hankins says. The high alkalinity of spring water can combine with heavy fish loadings to raise free carbon dioxide to toxic levels. So we remove the excess simply by blowing air counter-current to the water."

As new water from the spring enters the tanks, some of the old water is removed and pumped up to the greenhouses for Adler's research on water quality. After cleaning, the water is returned to the stream.

Institute director Selzer talks about the risks involved with the high-tech system. "With so much depending on pumps, a power outage causes serious problems. If we had no backup equipment, we'd have only about 5 minutes to save the trout if this happened."

So there is an auxiliary system at the site. An emergency generator provides power to automatically bubble oxygen into the tanks if the dissolved oxygen falls too low. There's also an elaborate alarm system that summons help if the computer detects a problem.

But what about flavor? Does being raised in such an environment affect the way the trout taste? Apparently not.

"We found the fish to be market quality. Our trained panelists are very sensitive to any bad flavor attributes in fish, and they found none in the trout from Shepherdstown," says Peter B. Johnsen who is in charge of the Food Flavor Quality Research Unit at ARS' Southern Regional Research Center in New Orleans.

Johnsen's research group also did a chemical analysis that showed the trout to be of acceptable quality. He says that the taste panel routinely evaluates fish from various aquaculture centers throughout the country.

Except for that used for research purposes, all the fish produced at Shepherdstown - nearly 15,000 pounds in 1991 and over 18,000 pounds in 1992 - was donated to the West Virginia Department of Natural Resources to stock trout streams.

The Low-tech Solution

The other end of the research spectrum at Shepherdstown incurs hardly any of the power-outage risks of the computer-managed system, yet produces healthy rainbow trout year round from a system that is practically maintenance free.

"We call it nature at work,'" says Charles E. Hicks, a research associate at the Institute. "No computers, no pumps, no fuss. In fact, once the equipment is in place, there's hardly any work required." He says this joint research with ARS, mandated by Congress, is in its third year. Its purpose is to evaluate the quality of the fish and demonstrate the feasibility of small aquaculture units for family farms in West Virginia.

"The first criterion is that the farm have a ground-fed spring, since the low-tech system operates on gravity," Hicks says.

At the Freshwater Institute, Morgan's Spring sends water through a 6-inch pipe into a small aboveground reservoir and on through 10 fiberglass tubs, situated in two rows of 5. Each tub is 5 feet in diameter and holds 360 gallons of water and about 750 trout of different sizes, to be harvested at different times.

The free-flowing water makes the tubs practically self-cleaning. It also ensures that the temperature remains fairly constant," Hicks says.

Since water from natural springs often contains nitrogen, an exchanger in a water-conditioning box adds oxygen to the water and releases the nitrogen.

As with the more complicated system, a farmer using the gravity system can harvest trout year round. It takes about 15 minutes a day to make sure that water is flowing through the system and that fish are getting food from response feeders hanging above each tub. These devices release small amounts of food whenever fish jump up - searching for insects - and bump the mechanism. This way, food costs are lessened, and water pollution from uneaten food is minimized.

According to Hicks, the entire lowtech system can be assembled in a barn, loaded on a trailer, and hauled with a pickup truck to selected sites.

"We now have 14 of these units the complete research model - operating in rural areas of West Virginia," he says.

If this initial success continues, the system will be a model for 13 other Appalachian states. A farmer can have one of the units set up and operating for less than $10,000.

Marketing is the real concern now. County extension agents are working closely with researchers and farmers to find a market niche. Thus far, a new prison in the vicinity has promised to buy trout raised in Summers and Fayette Counties.

But West Virginia farmer Robert Huffman doesn't have to worry about marketing his trout. From March to Labor Day, he says there's a steady stream of fishermen beating a path to both the ponds that he keeps fully stocked with beautiful mountain trout.

"Visitors pay $2 each to fish, and 20 cents per inch for the trout they catch. Most people take home more than enough for supper," he says.

Tucker County extension agent Larry Campbell encouraged Huffman to try the spring-fed trout-raising system. The mountain spring on Huffman's property supplies water for seven private homes in addition to the 4,500 trout in his project.

Huffman's 100-acre farm backs up to Black Water Falls State Park and is only a few miles from Canaan Valley State Park.

"An awful lot of my business comes from the tourists who visit the parks. They hear about the trout by word of mouth and come on out to fish," he explains.

Although the spring-fed system has been operational on his farm for just a little over a year, Huffman says he has already recovered his initial startup expenses. And this success was in spite of a near disaster that occurred only a few months after the system was installed.

"One night, a red lizard about the size of my thumb fell into the water and got tangled up in the gate valve, stopping the waterflow. Before morning, I had lost about 1,700 trout. I broke even with the trout raising anyway, but look forward to maybe making a profit next year," he says.

Retired from the West Virginia State Highway System, Huffman also raises cattle and hay to supplement his pension.

Other collaborators in this research include the West Virginia University Extension Service, and the West Virginia Departments of Agriculture and Natural Resources.

Additional information about U.S. aquaculture is available from USDA's National Agricultural Library. The Aquaculture Information Center gathers, computerizes, maintains and updates data on all aspects of the aquaculture industry. Contact the National Information Center, 10301 Baltimore Ave., Beltsville, MD 20705-2351. Phone (301) 504-5558, fax number (301) 504-6409.
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Author:Stanley, Doris
Publication:Agricultural Research
Date:Mar 1, 1993
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