2005 Annual Report 1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? A major challenge facing commercial catfish farmers is managing water quality to maintain fish health and achieve efficient production. High feeding rates used within heavily stocked catfish ponds result in dense algal blooms. While algal blooms recycle nutrients in the pond and provide much of the oxygen required for fish respiration, algae also cause many of the serious problems in warm-water aquaculture, including low oxygen (from algal respiration at night), off-flavors and toxic blooms. Dissolved oxygen is arguably the most critical water quality parameter in warm water aquaculture. Over $50 million in potential profit are lost annually from the direct effects of low oxygen. An additional $100 million may be lost from poor growth and food conversion and a variety of environmental and pathogenic diseases directly related to the stresses of poor water quality. Although, a variety of aerators and oxygen monitors is now commercially available, little is known regarding the impacts of sub-lethal oxygen levels on catfish production efficiency. Once these impacts have been identified and quantified, logical economic decisions with respect to water quality management can be made. Various aquatic microbes produce metabolites that impart ‘off-flavors’ to fish, rendering them unmarketable and adding $70 million to annual production costs. Oscillatoria perornata, a blue-green algae, is reported to be the major cause of 2-methylisoborneol(MIB)-related off-flavor in the Mississippi delta. Other algae produce other metabolites resulting in off-flavor and unmarketable fish, whereas other algal species produce toxic compounds causing direct fish mortality. Controlling these nuisance algae and maintaining optimum water quality must begin with a fundamental understanding of the algal species involved and environmental conditions controlling algal dynamics. The goal of this research project is to increase production economics from commercial warm water catfish ponds through improved water quality management. Improved management will result in more intensive catfish production (greater per-acre yields) across the industry. Higher per-acre production will require less ground water pumped for each pound of catfish produced, as well as less overall discharge to the environment. Two approaches will be used to accomplish this goal. The first will focus on the impacts of low dissolved oxygen on growth and production of catfish, and the development of improved equipment and techniques for oxygen management. The second approach will be the identification and control of nuisance algae, with an emphasis on those groups primarily responsible for off-flavors and toxic blooms. It is expected that both approaches will result in improved applied pond management techniques for the industry which will help to solve these costly production problems, increase efficiency and profitability, provide a quality product for consumers, and minimize environmental impacts of aquaculture. The objectives of this project are to:. 1)discover, develop, and apply methods to predict off-flavor episodes and manage off-flavor compounds;. 2)identify optimal water column conditions for balanced growth of bacteria, phytoplankton, and zooplankton resulting in reduced secondary metabolite formation, and enhanced fish survival and production;. 3)determine influence of chemical and biological factors on catfish respiration, growth and production, and develop and test management methods to minimize limits on production; and. 4)develop new equipment and technologies to improve profitability of catfish farming. Research planned under this research project will address several National Program Action Plan Components: Integrated Aquatic Animal Health Management (Component #2); Reproduction and Early Development (#3); Growth, Development and Nutrition (#4); Aquaculture Production Systems (#5); Sustainability and Environmental Compatibility of Aquaculture (#6); and the Quality, Safety, and Variety of Aquaculture Products for Consumers (#7). 2.List the milestones (indicators of progress) from your Project Plan. 1.1: Develop and test methods for remote identification of off-flavor producing algae. 1.2: Quantify degree of selective control of cyanobacteria through the use of a proprietary chemical treatment. 1.3: Measure efficacy of rapid purging techniques to reduce off-flavors to below detection levels. 2.1: Demonstrate that algal species composition can be controlled by pond fertilization. 2.2: Determine if optimized nutrient ratios in catfish ponds can reduce algal blooms. 2.3: Determine role of algal toxins in direct fish mortalities, and possible sub-lethal effects on fish health. 3.1: Determine the effects of sub-lethal DO concentration on feed consumption, growth and production of channel catfish. 3.2: On-farm trials of new technology (aerator placement). 4.1: Evaluation of U-tube aerators for application in commercial catfish ponds. 4.2: Develop acoustic technology that can effectively inventory mixed-size catfish populations in commercial ponds. 4.3: Develop improved source level for Aquascanner sonar system. 4a.What was the single most significant accomplishment this past year? Timely and accurate assessment of algal biomass is required to assure optimal conditions for fish grown in high stocking densities. USDA,ARS Catfish Genetics Research Unit collaborated with University of Nebraska to develop specific remote sensing models for the highly turbid productive waters found in catfish production ponds. This new model provided greater accuracy of algal biomass estimation than previous models by over 15%. This model has application in all inland waters and is particularly useful for rapid assessment of algal biomass in aquaculture systems. 4b.List other significant accomplishments, if any. Development of more efficient aeration systems is critical for the future of the catfish industry. USDA,ARS Catfish Genetics Research Unit collaborated with Southern Machine Welding Inc. (“Big John Aerators”) to design a prototype commercial-scale powered U-tube aerator which was installed in a pond at the National Warmwater Aquaculture Center in Stoneville, MS. The initial prototype shows promise, moving over 8,300 gpm. If the Phase-II design can meet all of the criteria necessary for commercialization, this aeration system could greatly increase the efficiency of catfish production in the US. Orientation of traditional paddlewheel aerators in large commercial catfish ponds can potentially impact water quality and fish production costs. USDA,ARS Catfish Genetics Research Unit collaborated with Dillard and Company Inc. to test a unique aerator placement strategy. While data collection is continuing on the ten 17-acre ponds used in this study the new system shows promise. If the final results are positive, farmers could easily adapt existing equipment to this new system, increasing fish production and reducing production costs. Development of effective inventorying methodologies is critical for the future of the catfish industry. NCPA, Univ. of Miss. collaborated with MSU-DREC and MS Valley State Univ. as well as some commercial operators: Harvest Select Inc. and Jim Murphy Farms to operate the Aquascanner Catfish SONAR to determine its effectiveness for performing such an inventory. This testing has confirmed that meteorological factors (wind and temperature gradients in the pond) as well as pond bottom features have a substantial impact on the SONAR’s operation and fish enumeration. As signal processing routines and data acquisition techniques are improved, this SONAR system could act as a valuable tool for pond inventorying. 4c.List any significant activities that support special target populations. Catfish farming is truly a national industry with over 1,100 commercial producers located in 13 states. While there are some large farms, the majority are small family-owned and operated, averaging only 160 water acres. The USDA/NASS Census of Aquaculture conducted in 2000 classified 84% of catfish farms as small businesses, with annual sales of less than $500,000, and 38% (515) with annual revenues of less than $25,000. In spite of recent historically low pond-bank prices, farmers have survived through increased efficiency, producing more fish on fewer acres each year. Last year (2004) the industry produced over 630 million (M) pounds at a wholesale price of 69.9¢/pound. Those dedicated catfish farmers are the primary customers of this research through the availability of innovative technologies, management strategies and equipment to increase their efficiency even more. Research on management of nuisance algae and dissolved oxygen is critical for success of all catfish farms, but will have far greater impact on smaller farms with a generally narrower profit margin. Catfish processors benefit from a more stable fish supply resulting from improved off-flavor management and detection methods. Average consumers also benefit from the increased availability of higher-quality, safer domestic products at a reduced price. 4d.Progress report. Under a Non-Funded Cooperative Agreement 6402-13320-002-06S, “Test of novel aerator placement strategy for managing dissolved oxygen on commercial channel catfish farms” was established with Dillard and Company, Inc, a commercial catfish producer. The purpose of this agreement (established on April 29, 2004) is to determine the effects on fish production, water quality and economics of concentrating paddlewheel aeration in large commercial ponds, compared to the current method of placing aerators to maximize total pond aeration and circulation. Ten 17-acre ponds were selected for use in the study and were brought into the study in pairs as they were stocked during the 2004 growing season. Each pair was stocked near the same date with a single batch of graded, similarly-sized catfish. One pond of each pair was aerated with the new aerator placement, and the other was aerated using the existing system. Ponds are being “clean harvested” by multiple seining as the fish reach market size. Water quality, feed input and fish production are being monitored. Some ponds have completed the first production cycle and have been harvested. Monitoring of electrical usage has been problematic due to faulty hour meters. While these meters have all been replaced, the second season study may be discontinued for uncontrollable reasons. Due to a severe industry-wide fingerling shortage, stocker-size fish were not available to restock all ponds for food-fish production after the first harvest, and some were used for fingerling-to-stocker grow out. Secondly, on July 1, 2005 the main electrical power line feeding the farm went down during the night, and a major fish loss occurred across the farm. This may impact data from the few ponds that had not yet been harvested after the first cycle. Available data will be analysed. A Non-Funded Cooperative Agreement, “Development of a powered u-tube aerator (“Power Tube”) for use in commercial fish ponds” with Southern Machine Welding, Inc. The purpose of this agreement (established on Nov. 11, 2003) is to develop and test a novel aerator design for use in commercial fish ponds. A prototype u-tube has been constructed and installed in a 0.4 ha pond at the MSU Delta Branch Experiment Station. The tube was fabricated from a 36” diameter corrugated culvert and was buried to a depth of 20 ft below the pond bottom. The motor, gear box, impeller and open loop vector AC drive were all installed as planned. This initial prototype shows promise. With an impeller speed of 150 RPM, the motor draws 12.7 amps (5.36 hp) and has an output of 8,300 gpm. A variety of diffuser types have been tested. Oxygen transfer efficiency tests have been conducted. It is expected that both the technical (improving efficiency) and practical (reducing cost and producing a unit that can operate reliably in a commercial environment) recommendations will be incorporated into a Phase II design for continued testing next year. This agreement is due to expire on October 31, 2005, but we anticipate a renewal to continue this high potential collaborative project. A Specific Cooperative Agreement, "Development and validation of remote sensing algorithms to detect cyanobacteria in catfish ponds" was established with the University of Nebraska. The purpose of this agreement (established 17 June 2004) is to develop remote sensing models specific for Case 2 waters. Development of models specific for highly productive turbid waters will result from this research. It is anticipated that the project will be completed in April 2006. 5.Describe the major accomplishments over the life of the project, including their predicted or actual impact. This research project 6402-13320-003-00D, “Optimizing catfish/water quality interactions to increase catfish production,” was formally initiated on December 14, 2004 after approval of the project plan by the Office of Scientific Quality Review following NP106 Panel Review. The project research will continue through April 30, 2010. This project replaces research project 6402-13320-002-00D, “Optimizing catfish/water quality interactions to increase catfish production efficiency”. Results over the life of the terminating research project can be found in the FY 2005 Annual (final) Report for that project. Major accomplishments and impacts expected over the life of the new research project are:. 1)discover, develop, and apply methods to predict off-flavor episodes and manage off-flavor compounds;. 2)identify optimal water column conditions for balanced growth of bacteria, phytoplankton, and zooplankton resulting in reduced secondary metabolite formation, and enhanced fish survival and production;. 3)determine influence of chemical and biological factors on catfish respiration, growth and production, and develop and test management methods to minimize limits on production; and. 4)develop new equipment and technologies to improve profitability of catfish farming. These accomplishments will reduce direct and indirect losses of catfish on commercial farms, resulting in increased production economics for farmers and improved products for consumers. 6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? A device to minimize water spray from alfalfa valves on pond workers has been designed, tested and publicized to fish farmers and scientists through a trade journal. Recommendation on oxygen management in catfish ponds have been disseminated through an industry trade journal, a research/industry newsletter, and several presentations to industry groups. 7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). James P. Chambers, C. Douglas Minchew and Rachel V. Beecham. 2005. “Biomass assessment in commercial catfish ponds”, Proc. of the 149th meeting of the Acoustical Society of America. May 15-20, 2005. Vancouver, BC. Page 2554. Chambers, J.P., Kleinert, D., Carpenter, B., Heffington, J., Minchew, C.D., Beecham, R.V. 2005. “AquaScanner Catfish Sonar”. Fish Farming Trade Show. February 3-4, 2005. Greenville, MS. Torrans, Les, Santucci, James. 2005. Inexpensive spray shield for alfalfa valves detailed. The Catfish Journal. 19(5):15. Torrans, Eugene L. 2005. Aeration in channel catfish ponds. Invited presentation and abstract. Aquaculture 2005. January 17-20, 2005. New Orleans Marriott. New Orleans, LA. P. 455. Torrans, Eugene L. 2005. Aeration and fish production. Invited presentation to the Fish Farming Trade Show. February 3-4, 2005. Greenville, MS. Zimba, P.V., Boyer, G., Carmichael, W.W. 2004. Toxic cyanobacteria in aquaculture systems. 2005 Toxicology and Risk Assessment Conference. Fairborne, OH. Walker, D., Boyer, G., Zimba, P.V. 2005. Cyano-toxin production and fish kills in reservoirs along the Salt River. Arizona, USA. Limnology and Oceanography. Feb 20-25, 2005. Salt Lake City, UT. Book of Abstracts. page 144. Johnson, R.M., Viator, R., Veremis, J., Richard, E.P., Zimba, P.V. 2005.Discrimination of sugarcane varieties with hyperspectral reflectance measurements and plant pigment analysis. 35Th American Society of Sugar Cane Technologists. Panama City Beach, FL. Book of Abstracts. page 24. Richardson, L., Mills, D.K., Zimba, P.V. 2005. Ecological complexity of black band disease of corals: physiological processes, chemical dynamics, and mechanisms of toxicity. Applied and Environmental Microbiology Annual Meeting. June 5-9, 2005. Atlanta, GA. Book of Abstracts. page 456. Mischke, C.C., Wise, D.L., Li, M., Zimba, P.V. 2005. Recent developments in the culture of Ictalurus punctatus fry: the importance of natural food. Aquaculture 2005. January 17-20, 2005. New Orleans, LA. P. 510.