2006 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? Why does it matter? This research directly addresses several components of the National Program 106 Aquaculture action plan such as: Section E (Early Life Stage Development and Survival) of the REPRODUCTION AND EARLY DEVELOPMENT component, Sections C (Sustainable Sources of Nutrients) and D (Nutrient Use and Feed Evaluation) of the GROWTH DEVELOPMENT AND NUTRITION component, Section E (Live Aquatic Animal Handling, Transport, and Inventory) of the AQUACULTURE PRODUCTION SYSTEMS component, Sections A (Aquaculture Feeds) and B (Water Use and Reuse) of the SUSTAINABILITY AND ENVIRONMENTAL COMPATIBILITY OF AQUACULTURE component, and Section D (Off-flavor Delayed Harvesting) of the QUALITY SAFETY AND VARIETY OF AQUACULTURE PRODUCTS FOR CONSUMERS component. Spending on seafood by United States’ consumers presently stands at over $55 billion annually. Demand far exceeds domestic production, generating a $7 billion dollar annual trade deficit—the third largest U.S. trade deficit after petroleum and automobiles. Increasing seafood production from wild fisheries to meet this demand and offset the deficit is not possible because most national and global wild-catch fisheries are fully exploited. The only way to close the enormous trade deficit in seafood and reduce America’s dependence on foreign products is to dramatically increase domestic aquaculture production. The channel catfish is the most important aquaculture species in the United States. In 2003, just over 300 million kg of channel catfish were processed, representing over half the total United States aquaculture production. Catfish aquaculture has generally been a profitable and rapidly expanding industry in the southeastern United States. However, yield has not increased in recent years and profits have decreased. We have addressed these problems through a multidisciplinary program focused on improving the efficiency of catfish production. The overall goal of this project is to develop management practices that provide greater control of production activities in channel catfish aquaculture. Specific areas of research have been identified through interactions with industry, extension service representatives, and research personnel in other disciplines and other states. 2.List by year the currently approved milestones (indicators of research progress) Objective 1: Develop feeds and feeding practices for optimal nutrition, increased production, and improved water quality of pond-raised catfish. Hypothesis 1: Economic performance of traditional catfish diets can be improved by manipulating content and sources of protein and carbohydrate. Milestones 12-month – Initiate pond feeding trials in a 2 x 4 factorial design using 32% crude protein feeds with 2 fish meal levels (0% and 8% menhaden fish meal) and 4 feed ingredient combinations (soybean meal + corn, soybean meal + corn + wheat middlings, soybean meal + corn + cottonseed meal, soybean meal + corn + cottonseed meal + wheat middlings). 24-month – Complete first year of first pond feeding trial. 36-month – Complete first feeding study. Initiate pond feeding trials in a 2 x 4 factorial design using 28% crude protein feeds with 2 fish meal levels (0% and 8% menhaden fish meal) and 4 feed ingredient combinations (soybean meal + corn, soybean meal + corn + wheat middlings, soybean meal + corn + cottonseed meal, soybean meal + corn + cottonseed meal + wheat middlings). 48- month – Complete first year of second pond feeding trial. 60-month – Complete second pond feeding trial. All data evaluated. Optimum feed formulation recommended. Hypothesis 2: Interactions among fish size (fingerlings, stocker-size, foodfish) and feeding schedule (satiation vs. various restricted rations) affect economic performance of catfish farming. Milestones 12-month – Initiate long-term pond feeding trial using three feeding regimes:. 1)feeding to apparent satiation once daily;. 2)feeding to apparent satiation once every other day; and. 3)feeding once daily to no more than 90 kg/ha. Harvest marketable fish and restock with fingerlings (complete year 1 of grow-out cycle). 24-month – Harvest marketable fish from study and restock with fingerlings (complete year 2 of grow-out cycle). 36-month – Harvest marketable fish from study and restock with fingerlings (complete year 3 of grow-out cycle). 48-month – Harvest marketable fish from study; harvest all remaining fish (complete year 4 of grow-out cycle, study complete). 60-month – Data evaluation complete. Optimum feeding strategy recommended. Objective 2: Increase the reliability, efficiency, and cost-effectiveness of catfish fry production through the use of new and improved technologies. Hypothesis 1: Implementation of new nursery pond management strategies can improve fry growth and survival on a commercial catfish farm. Milestones 12-month – Initiate and complete year 1 studies of “best management practices” for fry nursery ponds on commercial farm. Year 1 management strategy evaluated, modeled, and incorporated into new model and management strategy. 24-month – Initiate and complete year 2 studies of “best management practices” for fry nursery ponds on commercial farm. Year 2 management strategy evaluated, modeled, and incorporated into new model and management strategy. 36-month – Initiate and complete year 3 studies of “best management practices” for fry nursery ponds on commercial farm. Year 3 management strategy evaluated, modeled, and incorporated into new model and management strategy. 48-month – Initiate and complete year 4 studies of “best management practices” for fry nursery ponds on commercial farm. Year 4 management strategy evaluated, modeled, and incorporated into new model and management strategy. 60-month – All results analyzed. Final management strategy recommended. Hypothesis 2: Increased nitrogen fertilization rates will improve fry growth and survival. Milestones 12-month – Initiate studies in replicate fry ponds fertilized with different levels of nitrogen fertilizer. 24-month – Complete first N application rate study. Evaluate data and refine N application rate. Initiate second year of N application rate study. 36-month – Complete second N application rate study; analyze data; recommend optimum N fertilization rate to industry. Initiate P fertilization rate study. 48 month – Complete first P application rate study. Evaluate data and refine P application rate. Initiate second year of study. 60-month – Complete second P application rate study; analyze data; recommend optimum P fertilization rate to industry. Hypothesis 3: Zooplankton affect growth, survival, and immune response of catfish fry. Milestones 12-month – Initiate and complete first year of laboratory studies of the effect of feeding supplemental zooplankton on fry growth, survival, immune response, and survival to disease challenge. Refine diets based on year 1 results and repeat study using basic protocol. 24-month – Complete data analysis of second year study; refine diets and repeat study using basic protocol. 36-month – Complete data analysis of third year study; refine diets and repeat study using basic protocol. 48-month – Complete data analysis of fourth year study; refine diets and repeat study using basic protocol. 60-month – All results evaluated. Final recommendations made to industry. Objective 3: Apply engineering approaches to design new or modified live aquatic animal harvesting equipment. Hypothesis: Incorporating an induced electrical field into a seine improves harvest efficiency of pond-raised catfish. Milestones 12-month – Complete design, fabrication, and testing of components in vats. 24-month – Complete laboratory vat testing; redesign components. 36-month – Initiate and complete vat studies on capture efficiency of prototype seine; Initiate design and fabrication of pilot-scale seine. 48-month – Complete first year of comparative field study; modify seine as needed. 60-month – Commercial-grade seine developed and tested. Complete economic study. Objective 4: Increase the reliability, efficiency, and cost-effectiveness of catfish production through the use of new and improved culture system technologies. Hypothesis 1: Radical changes in the design of ponds, incorporating the concepts of fish confinement and water circulation, can improve catfish production efficiency. Milestones 12-month – Complete construction of “extensive” partitioned aquaculture system (PAS) and initiate performance optimization. Initiate construction of sidestream bypass partitioned aquaculture system. 24-month – Complete construction sidestream bypass partitioned aquaculture system; initiate performance testing and design optimization. 36-month – Initiate and complete year 1 of comparative fish growth trials in extensive and sidestream bypass partitioned aquaculture systems. 48-month – Complete year 2 of comparative fish growth trials in extensive and sidestream bypass partitioned aquaculture systems. 60-month – Complete year 3 of comparative fish growout trials. Results analyzed. Technology transferred. Hypothesis 2: Development of an environmental management system for pond aquaculture, consisting of proven or easily implemented technologies, can improve catfish production efficiency, reduce environmental impacts, and conserve water. Milestones 12-month – Develop Environmental Management System; initiate year 1 of comparative production trials. 24-month – Complete year 1 of comparative production trials; initiate year 2. 36-month – Complete year 2 of comparative production trials; initiate year 3. 48-month – Complete year 3 of comparative production trials; initiate year 4. 60-month – Complete year 4 of comparative production trials. Evaluate overall results and recommend EMS to industry. 4a.List the single most significant research accomplishment during FY 2006. Nursery pond fertilization to enhance phytoplankton and zooplankton populations is a common practice among all cultured species of fish and is especially important in catfish farming to provide large numbers of healthy fingerlings for the largest U.S. aquaculture industry. Previous catfish nursery pond fertilization recommendations were developed based on data from ponds located in a different state and produced variable results in Mississippi. By recognizing that ponds are nitrogen limited and not phosphorus limited as previously thought, modifications of fertilization practices have already produced more consistent results and lead to more efficient, economical fry production. The new fertilization recommendations being developed from this research are being quickly adopted by catfish farmers, even before this project is completed. An article on the new pond fertilization strategies has been carried in 12 newspapers and appeared in some agricultural magazines. 4b.List other significant research accomplishment(s), if any. Feed cost typically accounts for about 50% of variable operating costs in catfish production, and feeding practices have marked impacts on fish growth, production, feed efficiency, and profit in channel catfish farming. Mississippi State University scientists initiated in 2004 a four-year study to compare. 1)feeding to apparent satiation once daily;. 2)feeding to apparent satiation once every other day; and. 3)feeding once daily to no more than 90 kg/ha under a multiple-batch cropping system. Results from the 2004 and 2005 growing seasons showed that fish fed once daily to satiation were fed more feed and more market-size fish were harvested than those fed once every other day to satiation. The total amount of feed fed and market-size fish harvested were intermediate for fish fed once daily at a restricted ration. These feeding regimens had no significant impact on processing yield and fillet protein level, but fish fed to satiation every other day had significantly lower fillet fat because of restricted nutrient and energy intakes. Inefficient harvesting is seriously affecting the profitability of the catfish industry because market-sized fish that escape harvest continue to grow and create additional inefficiencies resulting from higher feed conversion ratios and carry-over of large fish that are unacceptable to processing plants. At least $50 million of revenue is lost annually due to inefficient harvesting. The best solution to these problems appears to be the development of new or improved harvest gear and methods. One possibility to improve the efficiency of harvesting catfish from ponds is to use electricity as a means of repelling fish. Worker safety is the major issue when considering using electricity to enhance a conventional seine. Safety issues must be resolved if there is to be any hope that producers will adopt all or part of the technology developed under this objective. Therefore, the successful design of an effective electrical circuit that will cut off the power to each panel of electrodes as they come out of the water is a major accomplishment. The demonstration that the individual components of the low powered electrical modules can be reduced significantly in size and weight is also important because of concerns about the effect of the panels on the total weight of a modified seine. Most United States aquaculture production comes from ponds which have the advantage of low capital cost and the relative reliability of fish production. However, traditional ponds need continuous management of oxygen concentrations and are susceptible to algae-related fish off-flavors, losses to avian predators, difficulties in disease control, inefficient fish harvesting, and the finite limit on fish production. Mississippi State University researchers have initiated a long-term study of the partitioned aquaculture system (PAS), which attempts to partition pond fish culture into distinct physical, chemical, and biological processes which are then linked water flow from highly efficient, low-speed paddlewheels. Physical separation of the fish culture process from enhanced algal production allows separate optimization of both processes and maximizes overall system performance and productivity. In the first year of production, a simple version of the PAS was constructed and found capable of sustained fish feeding rates of 150 to 200 pounds/acre per day without deterioration of water quality. Fish grew from about 0.1 pounds per fish to an average of 1.45 pounds/fish in a 6-month growing season. Total harvest weight was 16,910 pounds per acre, for a net fish production of 14,506 pounds per acre. This is about twice that achieved in traditional ponds. Fish survival was 99.6% at a feed conversion efficiency of 1.87 pounds of feed per pound of fish produced. Mississippi State University scientists at the National Warmwater Aquaculture Center in Stoneville, Mississippi, are evaluating a simple environmental management system to reduce the amount of waste produced within catfish ponds and decrease the volume of water discharged from ponds. After 2 years of study, average water discharge from ponds managed with the system was 60% of that from unmanaged ponds. Reducing effluent volume caused a concomitant reduction in waste discharge: mass discharge of total nitrogen, phosphorus, suspended solids, and 5-day biochemical oxygen demand was reduced by over 45% in ponds managed with the system. Catfish farmers can easily adopt these practices, which will allow catfish farms to be operated with little or no impact on the environment. 4c.List significant activities that support special target populations. Production inefficiencies related to feeding practices, nursery pond management, and harvesting in commercial catfish culture reduce profits and more efficient practices will benefit operators of small farms. The USDA Census of Aquaculture conducted in 2000 classified 84% of catfish farms as small businesses, with annual sales of less than $500,000. Of the 1,370 catfish farms in the United States, 38% (515) reported annual revenues of less than $25,000. Production inefficiencies disproportionately affect small farms because they are more susceptible to economic impacts related to interruption of cash flows. 4d.Progress report. Objective 1: Develop feeds and feeding practices for optimal nutrition, increased production, and improved water quality of pond-raised catfish. A 2 H 4 factorial experiment was initiated in FY 2005 using two fish meal levels (0% and 8% menhaden fish meal) and four feed ingredient combinations (soybean meal + corn, soybean meal + corn + wheat middlings, soybean meal + corn + cottonseed meal, soybean meal + corn + cottonseed meal + wheat middlings). Channel catfish were fed for one growing season in 2005 and are currently being fed for the 2006 growing season. Based on feed records at the end of the 2005 growing season, fish in the various treatments consumed similar amounts of feed. In September/October 2006, all fish will be harvested. Data to be collected will include feed consumption, weight gain, net production, feed conversion ratio, survival, processing yield, and fillet proximate composition. Channel catfish were fed with the following three feeding regimens for two growing seasons in 2004 and 2005 in a multiple-batch cropping system. The three feeding regimens are. 1)feeding to apparent satiation once daily;. 2)feeding to apparent satiation once every other day; and. 3)feeding once daily to no more than 100 pounds/acre. Market-size fish were selectively harvested from each pond at the end of 2004 and 2005 growing seasons and fingerlings were understocked in each pond in the spring of 2005 and 2006. Fish are being fed with the three feeding regimens as described previously. The first two year’s data showed that total amount of feed fed was significantly different among treatments. The total amount of feed fed was the highest for the daily satiation feeding regimen, followed by the daily restricted feeding, and the lowest for the every-other-day satiation feeding. Total weight of market-size fish selectively harvested followed the similar trend as the total amount of feed fed, but the difference between fish fed daily to satiation and at a restricted ration was not statistically different. No significant differences in processing yields (carcass, fillet, or nugget yields) and fillet protein concentrations were noted among different feeding regimens. There were no significant differences in fillet fat concentration between fish fed daily to satiation and at the restricted ration, but fish fed to satiation every other day had a lower level of fillet fat than the other two treatments. These data should be considered preliminary because fish are still being fed and not completely harvested. Objective 2: Increase the reliability, efficiency, and cost-effectiveness of catfish fry production through the use of new and improved technologies. New fertilization recommendations were implemented on the cooperative farm site. No differences in overall fry survival were detected from the previous years, however, consistent and desirable plankton blooms were obtained. Data collected from the study revealed areas of potential management improvements such as changing stocking rates. The management adjustments were beginning to produce positive results, however, extenuating circumstances have made it necessary to discontinue research at this particular farm. A new cooperative farm was identified, and the fertilization strategy was implemented. Caged fish are being placed in each pond when fry are stocked to develop relationships among early survival and final harvest results. If relationships exist, the farmer could ‘over-stock’ to make up for the early unexplained losses that occur. The variable nitrogen application study was repeated. A trend of increasing productivity (algal density, zooplankton density, and fish production) was apparent when increasing from 0 to 20 pounds N/acre, and decreased production above the 20 pound N rate. Using the refined application rates from 0 to 20 pounds N/acre, the study this year will compare productivity with more replicates and fewer treatments. Fry were divided among replicate treatments of zooplankton and commercial feed or commercial feed only. Fry from each treatment were either vaccinated against enteric septicemia of catfish or not. Growth and survival among treatments were then compared. After 14 days, fry fed supplemental zooplankton grew 14 to 17% larger than fry fed commercial feed or zooplankton alone. No differences in survival were detected among treatments. This year, laboratory studies are not being conducted because of space limitation. Next year, varied amounts of zooplankton will be fed to determine the amount needed to elicit a growth response in the fry. Objective 3: Apply engineering approaches to design new or modified harvesting equipment. The miniature fish stimulator and power supply module for the electric seine was redesigned. The system was further reduced in weight while maintaining the developed safety features. The output transformer was redesigned to operate at a higher frequency. In addition, the operating power was reduced from 60 to 10 watts. The results of vat tests using production-sized catfish indicated that the unit is only moderately effective as constructed. It was recently determined that the redesigned output transformer had a lower voltage than specified because of a tooling error by the manufacturer. Efforts are currently underway to get the manufacturer to correct this problem. The power supply and electrical circuitry will be re-tested once properly manufactured parts are obtained. Objective 4: Increase the reliability, efficiency, and cost-effectiveness of catfish production through the use of new and improved culture system technologies. A modified Partitioned Aquaculture System was constructed by dividing an existing 0.4-ha pond into two basins (an 0.2-acre algal basin and an 0.7-acre fish-confinement basin) that are hydraulically connected with inflow and outflow sluiceways and a low-speed paddlewheel. Aeration in the fish confinement area is provided by eight, highly efficient deep-water release membrane diffusers. The system was stocked with approximately 4,000 kg of catfish to optimize operating parameters. A paddlewheel speed of 1 rpm resulted in a water flow of 15.2 cubic meters/minute through the fish-confinement basin. This flow rate was adequate to prevent accumulation of waste ammonia in the fish-confinement area at fish feeding rates of 150 kg/ha per day. At sustained fish feeding rates of 150 to 175 pounds/acre per day, total ammonia concentrations have not exceeded 0.5 mg/L and dissolved oxygen concentration have remained above 3 mg/L. Fish grew from about 0.1 pounds per fish to an average of 1.45 pounds/fish in a 6-month growing season. Total harvest weight was 16,910 pounds per acre, for a net fish production of 14,506 pounds per acre. This is about twice that achieved in traditional ponds. Fish survival was 99.6% at a feed conversion efficiency of 1.87 pounds of feed per pound of fish produced. An Environmental Management System (EMS) was developed to reduce mass discharge of pollutants for catfish ponds. A water-level management practice was included in the EMS to reduce effluent volume. The other three practices were implemented to reduce the concentration of substances in effluents. Those practices were. 1)limiting daily feed inputs to 100 pounds/acre per day;. 2)using a 28% protein feed; and. 3)maintaining a maximum fish density of 7,000 fish/acre. Pollutant discharge and fish production from EMS ponds are being compared to unmanaged ponds. After 1 year of study, average mass discharge of total nitrogen, phosphorus, suspended solids, and 5-day biochemical oxygen demand has been reduced by over 45% in ponds managed with the EMS. Nearly all of the reduction in mass discharge was attributable to reduced effluent volume resulting from the water-level management scheme used in EMS ponds. 5.Describe the major accomplishments to date and their predicted or actual impact. This is only the second year of this 5-year project and accomplishments over the life of the project are identical to those reported in Question 4, above. All objectives are focused on improving production efficiency which, if attained, will improve the profitability of channel catfish farming. Application of successful research results will reduce dependence on fish meal as a feedstuff, lower feed costs, improve nutrient retention by fish (objective 1), and assure an inexpensive and dependable supply of seedstock for the industry (objective 2). Improvement of fish harvest (objective. 3)will increase production efficiency by removing most market-ready fish from ponds, thereby reducing carry-over of slow-growing large fish. Improved harvesting technology will also reduce the time and labor required for seining. The development of novel pond production methodologies (objective. 4)can potentially enhance overall production efficiency, reduce environmental impacts, and reduce water use. The overall benefits of this project will be the development of techniques to enhance economic performance, improve global competitiveness, and allow domestic aquaculture to reduce dependence on imports to meet the U.S. demand for seafood. 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? This is the first year of this comprehensive 5-year project, and opportunities for technology transfer specifically related to the project have been limited. Preliminary information from feeding practice studies and from the environmental management studies have been published in popular articles, bulletins, research reports, book chapters, and scientific journals, which are accessible to various audience including catfish producers, feed mill managers, and scientists. Some information has also been presented at workshops and scientific meetings. More definitive results on all objectives should be available in the third, fourth, and fifth years of the project. Technology related to fertilization and zooplankton management is being transferred to farmers through personal consultation and workshops. The Mississippi State University Office of Agriculture Communications wrote an article on the new pond fertilization strategies. The story was used in 12 newspapers and appeared in some agricultural magazines. Several farmers in Mississippi have already adopted the nursery-pond fertilization practices studied in this project, even before the project is complete. By recognizing ponds are nitrogen limited and not phosphorus limited as previously thought, modification of fertilization practices have already produced more consistent results and lead to more efficient, economical fry production. Similarly, farmers and state regulatory agencies have shown interest in the promising preliminary results from the first two years of work on the Environmental Management System. Several farmers have adopted formal water management schemes similar to the one in this project. 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). Hargreaves, J.A., Tucker, C.S. 2005. Conditions associated with sub-lethal ammonia toxicity in warmwater aquaculture ponds. World Aquaculture. 36(3):20-24. Li, M.H., Peterson, B.C., Janes, C.L., Robinson, E.H. 2006. Comparison of diets containing various fish meal levels on growth performance, body composition, and insulin-like growth factor-I of juvenile channel catfish of different origin. Catfish Farmers of America Research Symposium, San Antonio, TX. Abstract No. 30. Li, M.H., Robinson, E.H., Hogue, C.D. 2006. Catfish nutrition: feeding food fish. Mississippi State University-Extension Service Publication No. 2414. Li, M.H., Robinson, E.H. 2006. Trials find feeding frequency factor in catfish performance. Global Aquaculture Advocate. 9(3):46–49. Li, M.H., Robinson, E.H., Mischke, C.C., Torrans, E.L., Bosworth, B.G. 2006. Effects of organic fertilization and “organic” diets on production of channel catfish in earthen ponds. Aquaculture America, Las Vegas, NV. Abstract No. 162. Lim, C., Yildirim-Aksoy, M., Shelby, R., Li, M.H., Klesius, P.H. 2006. Influence of dietary levels of fish oil and vitamin E on growth and resistance of channel catfish to Edwardsiella ictaluri challenge. Aquaculture America, Las Vegas, NV. Abstract No. 167. Mischke, C.C. 2006. Managing natural productivity in channel catfish nursery ponds. Global Aquaculture Advocate. 9(3):52-55. Mischke, C.C., Avery, J. 2005. Thad Cochran National Warmwater Aquaculture Center. Fish Culture Section of the American Fisheries Society Newsletter. 2005. (July):4-6. Mitchell, A.J., Wise, D.J., Snyder, S., Mischke, C.C. 2006. Optimizing slurried-hydrated lime pond-shoreline treatments for aquatic snails vectoring trematodes to cultured fish [abstract]. Catfish Farmers of America.. Paper No. 21-30. Robinson, E.H., Li, M.H. 2005. A summary of nutrition research conducted under a cooperative agreement between MAFES and Delta Western Research Center. Mississippi Agricultural and Forestry Experiment Station Bulletin No. 1144. Robinson, E.H., Li, M.H. 2006. Catfish nutrition: use of all-plant diets to grow food fish. NWAC News. 9(1):8. Robinson, E.H., Li, M.H., Hogue, C.D. 2006. Catfish nutrition: feeds. Mississippi State University-Extension Service Publication No. 2413. Robinson, E.H., Li, M.H., Hogue, C.D. 2006. Catfish nutrition: nutrient requirements. Mississippi State University-Extension Service Publication No. 2412. Tucker, C.S. 2006. Water-level management and BMPs cut water use and pond effluents. Global Aquaculture Advocate. 9(3):50-51. Tucker, C.S. 2005. Limits of catfish production in ponds. Global Aquaculture Advocate. 8(6):59-60 Tucker, C.S. 2005. Pond aeration. Southern Regional Aquaculture Center Publication 3700. USDA Southern Regional Aquaculture Center, Stoneville, MS. Tucker, C.S. 2005. Improving reproductive efficiency to produce hybrid catfish fry. The Catfish Journal. 19(8):14 Tucker, C.S., Silverstein, P., Camus, A., Bilodeau, L., Wise, D., Waldbieser, G. 2005. Channel catfish virus disease and NWAC103 catfish. The Catfish Journal. 19(5):8. Zimba, P.V., Mischke, C.C. 2006. Plankton-nutrient dynamics in channel catfish fry and freshwater shrimp growout ponds. World Aquaculture. 37(2):28-31. Review Publications Li, M.H., Robinson, E.H., Bosworth, B.G. 2005. Effect of periodic feed deprivation on growth, feed efficiency, processing yield, and body composition of channel catfish. Journal of the World Aquaculture Society 36:444-453. Li, M.H., Robinson, E.H., Mischke, C.C., Bosworth, B.G., Torrans, E.L. 2006. Effects of organic fertilization and "organic" diets on production of channel catfish in earthen ponds. North American Journal of Aquaculture 68:53-62.