• Genetic Improvement
• Integrated Aquatic Animal Health Management
• Aquaculture Production Systems
• Sustainability and Environmental Compatibility of Aquaculture
• Growth, Development, and Nutrition
• Quality, Safety, and Variety of Aquaculture Products for Consumers

The ARS Aquaculture National Program expanded in FY 2000 in four of seven program areas: genetic improvement; integrated aquatic animal health management; aquaculture production systems; and sustainability and environmental compatibility of aquaculture.

Dr. Henry (Hank) Parker returned from a temporary assignment to the Industrial College of the Armed Forces, National Defense University, Ft. McNair, Washington, D.C., and is Acting Director, U.S. Horticultural Research Laboratories, Ft. Pierce, Florida, until January 19, 2001.

Dr. Lewis (Lew) Smith Acting National Program Leader for Aquaculture submitted a article that was published in the May, 1999 issue of Aquaculture Magazine, entitled “ARS Aquaculture Research Progress Reports.”

William (Bill) Wolters served the National Program Staff in drafting reports to the U.S.Senate on the ARS Aquaculture Program, and an ARS program initiative entitled “Aquaculture Research for the Future: Five-Year Research Plans.”

The Aquaculture National Program Planning Workshop is scheduled for September, 2001.  An ARS program and facility planning meeting was held in Orono, Maine on October 20, 1999, with a follow-up visit on November 11, 1999.  Congress appropriated $2.5 million in FY2001 for architectural and design of an aquacultural facility in Maine. 

The new National Center for Cool and Coldwater Aquaculture in Leetown, West Virginia, will be dedicated in the spring of 2001.

Investments in ARS Aquaculture Research is paying dividends with an improved line of catfish released in February, 2001, and a vaccine developed by ARS against enteric septicemia that was available to catfish farmers for the 2000 growing season.

Genetic Improvement

Since there has been limited genetic improvement of aquaculture stocks, there are major opportunities for improvement through traditional animal breeding, broodstock development, germplasm preservation, molecular genetics, and allied technologies. Research will address improvement of growth rates, feed efficiency, survival, disease resistance, fecundity, yield, and product quality; genetic characterization and gene mapping; and conservation and utilization of important aquatic germplasm.

Genetic variation in catfish.  Information on genetic variation is critical to designing catfish breeding programs for simultaneous improvement of multiple economically important traits.  ARS scientists of the Catfish Genetics Research unit, Stoneville, Mississippi, evaluated over 100 USDA103 line catfish families for growth, feed consumption and efficiency, mortality following an experimental disease resistance challenge, and genetic markers correlated with these important traits.  Significant genetic variation was found for food consumption and growth, but not for disease resistance.  The information on genetic variation and genetic markers is being incorporated into a multi-trait selection program to develop improved catfish lines with superior performance.

Catfish Genetic Map.  Efficient genetic selection using molecular markers requires a genetic map with markers that cover the entire genome.  The first detailed genetic map of the catfish genome was produced by the Catfish Genetics Research Unit, Stoneville, Mississippi, following the co-inheritance of 264 markers in 144 offspring of two catfish families.  This map will be useful for the selection of traits that are difficult to measure, such as disease resistance and fillet yield.

Genetic improved line of catfish.  Catfish with growth rates requiring more than one season to achieve market size cost more to produce.  ARS scientists at the Catfish Genetics Research Unit in Stoneville, Mississippi, have developed a genetically improved catfish line, USDA103, with improved growth.  From the 1998 and 1999 spawning seasons, over 1.7 million USDA103 line catfish fry have been supplied to Mississippi State University for stocking earthen ponds at the Thad Cochran National Warmwater Aquaculture Center.  Fish are currently being reared for a total of three growing seasons to a size and age recognized by the industry as sexually mature broodfish and released to commercial producers.  Results of experimental trials demonstrated USDA103 catfish have excellent growth due to higher feed consumption, and following recommended management guidelines should produce marketable catfish faster than the fish currently being cultured.

Integrated Aquatic Animal Health Management

Despite progress in aquatic animal health, significant losses to diseases still occur. Research will address improvement of survival, growth, vigor, and well-being of cultivated aquatic animal stocks through integrated aquatic animal health research; improved technologies and practices, such as population health management; and development of health management products, including vaccines and therapeutics, and disease detection/diagnostic techniques.

Copper sulfate moving toward approval.  Few chemicals and drugs are approved by the U.S.  Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) for treatment of sick food fish.  The small potential market for chemicals and drugs used to control diseases in aquaculture places in minor-use category, and requires coordinated partnerships to acquire approvals.  Scientists at the Harry K. Dupree Stuttgart National Aquaculture Research Center completed target animal safety data on copper sulfate in support of a new animal drug approval by EPA for its use in control of ichthyopthiriosos in channel catfish.  If the data is acceptable, three of the necessary four requirements will have been met for FDA approval of a new animal drug.

Algal toxins cause catfish moralities.  Infectious diseases and water quality problems are well-established causes of catfish moralities.  ARS scientists at Aquaculture Systems Research, Pine Bluff, Arkansas, Catfish Genetics Research, Stoneville, Mississippi, and University collaborators in Arkansas and Mississippi established that microcystin/anatoxin - type toxins were likely involved in several catastrophic fish kills on commercial catfish farms.  Algal control and management strategies are being evaluated.

DNA markers for disease resistance.  Genetic improvement of catfish for traits that are difficult to measure such as disease resistance, will require information on the different genes controlling those traits.  Scientists at the Catfish Genetics Research Unit, Stoneville, Mississippi, developed a fast, low-cost method to identify genes and DNA markers for disease resistance in channel catfish.  Over 2500 different genes were sequenced and identified, and over 200 unique genetic markers were found associated with these genes.  These genetic markers will be used in a catfish breeding program to develop catfish with improved disease resistance.

Vaccine developed against Streptococcus iniae.  Streptococcus iniae can infect both fish and people.  Scientists at the Aquatic Animal Health Research Unit, Auburn, Alabama, developed an injectable vaccine against Streptococcus iniae under a cooperative research and development agreement with Intervet.  Field tests with Kent SeaTech (Trust Agreement) with hybrid striped bass demonstrated effectiveness.  Intervet is in the process of obtaining a license to manufacture and a U.S. patent is pending.

In ova vaccination of channel catfish eggs  Scientists at the Aquatic Animal Health Research Unit, Auburn, Alabama, were awarded a patent demonstrating that fish eggs could be immunized, resulting in fry resistant to infection with Edwardsiella ictaluri.  This process provides early protection at low cost.

Growth, Development, and Nutrition

There are substantial opportunities to improve the growth, development, and nutrition of cultivated aquatic organisms.  Research will address improving survival, growth rates, feed conversion, environmental tolerances, and feed formulations and feeding strategies to reduce dependence on marine fish-based protein in aquaculture diets.

Thiamine improved growth.  Scientists at the Aquatic Animal Health Research Unit demonstrated that 4 milligrams of Thiamine /kg feed improved fish growth and production.  This vitamin can economically be supplemented for optimal growth to fish diets.

A new and practical shrimp diet.  Scientists at the Oceanic Institute, Hilo, Hawaii, developed and evaluated a new shrimp diet for ARS.  Shrimp that were fed the new feed formulations, grown under outdoor zero-water-exchange conditions, and subjected to modified feed management strategies grew at a rate as much as twice that normally observed by commercial shrimp farmers in the U.S.  Shrimp reached market weight within 8 weeks, compared to the commercial average of 12-17 weeks.  These results have important implications for U.S. shrimp farmers in terms of improved water quality (zero-water-exchange has no detrimental impact on the environment) and reduced feed costs (shrimp in this study received as much as 30 percent of their total nutritional intake from the living microbial food organisms present in this new culture system).

Aquaculture Production Systems

There are opportunities to improve the performance of aquaculture production systems through development and application of innovative engineering approaches and technologies. Research will address development and successful application to aquaculture of new technologies as well as relevant existing technologies and engineering presently employed in other sectors of the economy.

Aquaculture recirculation system evaluated.  Increasing fin-fish production in North America to meet increased worldwide demand will be difficult because of stringent water pollution control and water use permits, as well as limited availability of large, high-quality water sources.  To meet this challenge, scientists at the Freshwater Institute designed and evaluated for ARS, a partial recirculating system capable of providing uniformly healthy water quality, optimized water velocities for fish health, and rapid, gentle, and efficient solids removal.  This system is capable of supporting high production densities on about 20 percent of the flow required within a single-pass system, and through the use of Cornell-type dual-drain circular culture tanks, produces a small and more concentrated waste stream that can be treated more economically and efficiently.  This system offers key advantages over traditional fish culture in serial-reuse raceway systems, including an overall waste capture efficiency of 80 percent.

Sustainability and Environmental Compatibility of Aquaculture

The goal is to protect and conserve the nation's water resources and natural environments by conducting research and technology transfer to improve the sustainability and environmental compatibility of aquaculture production systems.  A primary concern is the protection and conservation of the nation's water resources.

Natural product-based algicide evaluated.  Bioaccumulation of foul-tasting monoterpenes from blue-green algae in the flesh of catfish is a costly problem for the catfish industry.  ARS scientists at the Natural Products Utilization Research Unit, Oxford, Mississippi, have discovered several selective natural product-based-blue-green algaecides and are in the process of testing and developing one of them.  Success will provide farmers with an environmentally safe method of eliminating unwanted blue-green algae from aquaculture ponds.

Quality, Safety, and Variety of Aquaculture Products for Consumers

The goal is to improve the quality, safety, and variety of aquaculture products through research and technology transfer. Research will address improvement of the safety, freshness, flavor, texture, taste, nutritional characteristics, and shelf life of cultivated fish and shellfish, and development of new value-added products and processes.

Blue-green algae - off-flavor management.  Off-flavors in catfish cost producers in delayed marketing of fish.  ARS scientists at the Catfish Genetics Research Unit, Stoneville, Mississippi, Food Processing and Sensory Quality Research, Southern Regional Research Center, New Orleans, Louisiana, in collaboration with Mississippi State University Agricultural and Forestry Experiment Station evaluated the potential of diuron to control off-flavor in channel catfish in laboratory tanks and in ponds. Research demonstrated efficacy in diuron in controlling target blue-algae in catfish production ponds, as well as in laboratory bioassays.  Algal species that produce off-flavors were more susceptible to this compound than other algal species.  Information on the efficacy of diuron will aid the industry in producing a high quality flavored product at less cost.

Diuron for off-flavor control.  Diuron is currently the most effective algaecide for management of off-flavor in catfish ponds; however, use of diuron by catfish farmers is contingent upon annual EPA approval of Section 18 emergency-use exemptions because full registration has not been granted.  Research by scientists at Mississippi State University and USDA/ARS Catfish Genetics Research Unit in Stoneville, Mississippi, demonstrated that residue levels of diuron in the edible tissue of fish from treated ponds are only about 60 percent of that expected from pharmacokinetic models.  This information provides strong evidence for the safety of this off-flavor treatment, which will be valuable in future, petitions to EPA for full registration of this effective off-flavor management tool.