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2001 ISSUE

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Originally published in the Winter 2001 Virginia Tech Research Magazine.

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Aquaculture:

Ocean-friendly, market-savvy wave of the future

By Angela Correa
Department of Food Science and Technology

Mussel larvae are parasites of fish, so why does Virginia Tech have a Mollusk Conservation Center? Find out here.

Overfishing, bioinvasion, and pollution are blamed for declining fish catches worldwide. To reverse the trend, wild harvesting of fish and shellfish faces increasing limitations, tariffs, and regulations. These strictures have resulted in higher prices and the disappearance of small businesses in the face of powerful multinational corporations.

“Fishing has always been a high-risk occupation, but perhaps more than ever, it is a perilous time to be a fisherman,” says George Flick, University Distinguished Professor of Food Science and Technology and member of the Commercial Fish and Shellfish Technologies (CFAST) program.

Flick grew up in Louisiana, where the waters provide a livelihood for thousands, and seafood is a staple for thousands more. “But in terms of dollars, the seafood industry holds only a fraction of the total market for meats,” he says. “Wild harvesting is too unpredictable, which promotes unpredictability along the entire supply chain. Good seafood is a valued product, but it won't make it to the table as often as steak or chicken until production and distribution of seafood catches up.” In Virginia, Flick has spent decades helping watermen and serving consumers — on the boats, on the docks, and in the seafood processing plants. Now he is helping the industry change course.

Americans consume 15.3 pounds of fish and shellfish per person per year, less than most developed nations. Fish and shellfish are among the only food items that still depend heavily on wild harvesting. Other major sources of meat have been domesticated; bred to maximize hardiness, growth, and disease resistance; and studied to develop treatments and facilitate handling. Now aquaculture is catching up. As the fastest-growing segment of agriculture in the United States and around the world, farm-raised fish and shellfish make up a third of U.S. seafood consumption.

Historically, the reluctance to undertake commercial aquaculture may be due to the relatively alien environment that fish and shellfish require. Land animals, after all, have the same basic needs as their caretakers — adequate shelter, balanced nutrition, fresh water, and clean air. The aquaculturist must monitor and control such additional factors as fish density, lighting, biosecurity, and water quality. That is tantamount to asking a rancher to control the composition of the air his herd breathes.

Virginia Tech’s research in finfish and shellfish culture has served to identify species especially suited for aquaculture, and to promote the sustainable development of the aquaculture industry.

Indoor recirculating systems

Virginia Tech’s aquaculture research focus is on indoor recirculating systems, not on ponds, or cages placed in their natural ocean or freshwater environments. Outdoor fish farming is entirely subject to environmental conditions. It also places a substantial burden on the environment. Unlike these types of systems, “a well-designed recirculating system provides the aquaculturist with the opportunity to improve water quality and to closely manage waste streams,” says Greg Boardman, CFAST member and professor of civil and environmental engineering. “Also, the footprint for a recirculating system is relatively small, which allows for easier monitoring and analysis of problems.”

Recirculating systems mitigate or even eliminate the environmental threat by minimizing water inflow and outflow from a facility, using waste materials as a valuable resource when possible, and by providing a buffer between the facility and the natural environment, Boardman explains. Engineering research in the areas of nutrient removal and effluent management are resulting in strategies that conserve energy and capital.

Successful aquaculture is inherently multidisciplinary, and at Virginia Tech, it involves more than 20 scientists in the College of Natural Resources, the College of Agriculture and Life Sciences, the College of Engineering, and the Virginia-Maryland Regional College of Veterinary Medicine working under the CFAST umbrella. In the area of recirculating aquaculture, CFAST identifies research needs and develops the means to satisfy them. The result is a body of species- and system-specific research that nurtures the emerging recirculating aquaculture industry.

Before farm-raised fish reach your table, researchers identify species with favorable growth rates and disease resistance that are able to tolerate the daily stresses of human contact and other aspects of an artificial environment. Subsequent research addresses disease prevention, selective breeding, nutrition, systems engineering, management practices, and maintenance of optimal water quality through mechanical and biological remediation. Once animals can be consistently raised to market size, a pilot system is scaled up into a commercial production facility. The scientists also address questions of food processing, quality, safety, product development, marketing, and economics. At every step, attention must be given to maximizing growth and maintaining health while minimizing costs and environmental effects.

Flounder researcher Michael Schwarz notes, “Recirculating aquaculture is a complex undertaking, but one that has immense potential to transform the seafood industry.”

Virginia Tech Aquaculture Center

The Virginia Tech Aquaculture Center is the program’s core freshwater facility. Located on campus in Blacksburg, it includes laboratories for testing new designs, exploring spawning regimens and optimized feeding, conducting selective breeding studies, and evaluating the efficiency of system components under stress.

“The strength of the center is that different students from all over the university can be working on aspects of raising a certain species,” says Mark Schmitz, who received his master's degree in fisheries in May 2000. “We could have a biosystems person looking at controlling ammonia levels in the water, a vet-med student gathering information on viruses or other irritants, a food science person checking for human pathogens in the finished product, a fisheries person working out a strategy to induce spawning year-round, an engineering student making sure that there is a way to reduce the impact of wastes that leave the system, and an economist figuring out how to make it all add up to a profit.” The collaboration is crucial to understanding the full possibilities of each individual project.

Some of the species being researched are relatively new to America’s dinner table, such as tilapia or arctic charr. Other species, such as striped bass, yellow perch, or trout, have been rare treats found in season at select restaurants or in the homes of successful anglers. Aquaculture should enable year-round availability and stable pricing for these products.

Aquatic medicine

Virginia Tech is one of only 11 universities in the nation with an aquatic medicine program, based in the College of Veterinary Medicine. Current work includes the development of preventive therapies and novel molecular diagnostic assays, as well as identification of standard blood chemistry values for individual species, and investigation of the effects of diseases, approved drugs, and management practices on the overall health of fish. Stephen Smith, associate professor of biomedical sciences and pathobiology, points out, “Fish raised in a recirculating environment cannot swim away from harmful conditions. With the help of pumping and aeration devices, a disease can infest a recirculating system in a matter of hours, causing huge losses. Aquaculturists must be able to monitor the condition of their stocks, identify health problems before they become unmanageable, and have the tools to act fast to curtail the effects of disease.”

Salt-water facility

The CFAST program also has a saltwater facility. The marine recirculation program is at the Virginia Seafood Agricultural Research and Extension Center in Hampton. The current focus is on culture of summer flounder, a high-value species with a good tolerance for handling. Researchers are developing an elite broodstock and working to determine the nutritional requirements for the species. “Wild summer flounder exhibit widely varying growth rates,” says Ryan Cool, a Virginia Tech graduate who works as a technician at the Hampton facility.

“You could have two 16-month-old fish, and one could weigh as much as 700 grams while another might just weigh 50 grams (454 grams = 1 pound). You can see why it is necessary to select for the faster-growing fish.” Low-energy saltwater recirculation systems are currently used to research genetic selection, water treatment, optimal nutrition, disease risks, and management protocols.

Researchers at the waterfront facility have served watermen and seafood processors for decades, addressing issues ranging from the pollution of shellfish beds to maintaining freshness and safety during harvesting and processing. Now they are helping watermen and processors to explore the possibilities of recirculating aquaculture, and businesses in the state are taking note. Along Virginia’s coast there are several examples of facilities that are turning to aquaculture to supplement their wild harvesting efforts. Cherrystone AquaFarms in Cape Charles, Pinefield Farm, raising tilapia in Kilmarnock, and Blue Ridge Aquaculture, the largest recirculating tilapia farm in the nation, located in Martinsville, are prime examples of this trend.

Food safety

Seafood scientists at Virginia Tech have developed food safety and sanitation guidelines for aquaculture operations, and are developing new products and markets to maximize profits. “Applying HACCP (Hazard Analysis and Critical Control Point) principles to aquaculture operations greatly increases consumer and regulatory confidence in these products,” says Michael Jahncke, director of the Hampton center.

Safety and sustainability are “the prime directive” for recirculating aquaculture. The goal of the research is to produce a wholesome, high-quality product while making wise use of natural resources and reclaiming useful portions of the waste stream. “The goals are a profitable livelihood and a nutritious, desirable product,” says Flick.

Economics

Economics research aims to minimize expenditures, provide guidelines for growth, and create scaleable models for aquaculture facilities. The new Southwest Virginia Aquaculture Center in Saltville will be used to conduct further research into scale-up and commercialization of aquaculture. The Saltville facility, which will have the capacity to raise 40,000 pounds of fish per year, will function as a commercial enterprise using principles and practices developed at Virginia Tech, and will yield invaluable data on the real-world economics of starting and maintaining an aquaculture business.

CFAST contributions to the science and application of recirculating aquaculture include education, outreach, and collaborative opportunities with peer institutions. CFAST hosts international conferences on recirculating aquaculture and has launched the International Journal of Recirculating Aquaculture. The Southwest Virginia Aquaculture Center will demonstrate the potential of recirculating aquaculture as a responsible, practical, and profitable way to bring new jobs and industry to geographic areas where fishery-related enterprises had never been an option. The center will offer courses and educational materials for those entering the field of recirculating aquaculture, modules for K-12 science and economics education, tours for the public, opportunities for volunteers, and guidance in the development of certification requirements for aquaculture workers.

Recirculating aquaculture is emerging at a good time to meet market demands for seafood and to serve the changing needs of land-based farming operations. As research and technology transfer continue, recirculating aquaculture enterprises could become commonplace, making fresh fish locally available year-round, improving the lands and oceans, and generating a livelihood for many Virginians.