Progress 05/06/01 to 12/13/04
Outputs
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? This research project was completed/terminated on December 13, 2004. Future research plans and milestones will be found in the FY 2005 annual report for research project, 6402-13320-003-00D. 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 and fish 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 from poor water quality. Although, a variety of aerators and oxygen monitors are 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 MIB-related off-flavor in the Mississippi Delta. Other algae also produce metabolites resulting in off-flavor and unmarketable fish, and some 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 channel 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 channel 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. This project had four specific goals: 1) determine effects of sub-lethal oxygen concentrations and the modifying influences of various physical, chemical and biological factors on catfish metabolism and respiratory efficiency; 2) develop and test equipment and management practices to optimize respiratory efficiency (minimize oxygen stress) and intensify production on warm-water fish farms; 3) identify problematic algal species responsible for secondary metabolite production (including toxic and off-flavor compounds) that impact catfish production; and 4) identify techniques/technologies for controlling harmful algal
blooms, including biocontrol, natural algicidal products, and synthetic herbicides for use in aquaculture systems. Research planned under this research project addressed 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. Year 1 (FY 2001) - Build and test laboratory respirometer for measurement of catfish metabolic rate; preliminary tests of sub-stratum aerators and zero-discharge intense aeration catfish production system; equip laboratory with field and laboratory supplies to begin experimentation on diuron efficacy in controlling off-flavor producing algal species; setup High Performance
Liquid Chromatograph (HPLC) and pulse amplitude fluorescence meter to detect physiological state of algae; assist with field testing of chemicals for control of off-flavor producing algae. Year 2 (FY 2002) - Determine oxygen consumption rate of USDA-103 channel catfish as affected by ambient oxygen content, temperature, fish size; continue development as indicated by preliminary results on sub-stratum aerators and zero-discharge intensive aeration; initial assessment of companion species; develop Palm-pilot software to allow for the collection and computerization of oxygen data on commercial fish farms; complete experimentation on efficacy of diuron and write up research results; isolate algal clones producing toxins and begin tests in laboratory to assess the environmental cues responsible for toxin production by cyanobacteria; continue collaborative efforts in field evaluation of compounds for control of off-favor producing microalgae; setup a CRADA with Louisiana Tech to assess
biocontrol of off-flavor producing species of algae with his bacteria exhibiting algicidal properties. Year 3 (FY 2003) - Conduct baseline respiratory physiological comparisons of USDA-103 with other channel catfish lines/strains and hybrids; assess impacts of high CO2/low pH on respiration (Bohr effect) and potential of commercial buffers (hydrated lime and sodium bicarbonate) to modify pond environment; develop techniques for remote sampling of catfish respiratory physiology, including catheters and telemetry; pond trial(s) of promising companion species; establish algal toxin LD50 levels for various catfish growth stages; finalize laboratory assessment and management alternatives for toxin research; initiate field experiments using management recommendations. Year 4 (FY 2004) - Determine impacts on respiration of various conditions/pathologies proliferative gill disease (PGD or hamburger gill), and methemoglobinemia (brown blood disease); further development of remote sampling of
catfish physiology with aim of physiological telemetry of free-swimming catfish in a pond environment; final studies on water quality management, companion species and aeration systems. Year 5 (FY 2005) - Complete studies and finalize recommendations on commercial techniques to most efficiently and economically manage pond oxygen concentrations. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. Complete studies and finalize recommendations on commercial techniques to most efficiently and economically manage pond oxygen concentrations. Milestone Substantially Met 4a What was the single most significant accomplishment this past year? Since this final report only covers a period of ten weeks (October 1- December 13, 2004), there are no specific accomplishments reported for that period. 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 (2003) the industry produced over 661 million (M) pounds at a wholesale price of 58.1c/pound, compared to 593 M pounds at 75. 1c/pound only three years ago. 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 an Non-Funded Cooperative Agreement, Development of a powered u- tube aerator (Power Tube) for use in commercial fish ponds with Southern Machine Welding, Inc. in Quinton, Alabama, was established on Nov. 11, 2003 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 Mississippi State University Delta Branch Experiment Station. The tube was fabricated from a 36 diameter corrugated galvanized culvert and was buried to a depth of 20 below the bottom of a
0.4-hectare pond. 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 8300 gpm. A variety of diffuser types will be tested. Oxygen transfer efficiency tests will be conducted. A Non-funded Cooperative Agreement, Test of novel aerator placement strategy for managing dissolved oxygen on commercial channel catfish farms established on April 29, 2004 with Dillard and Company, Inc. a commercial catfish producer was established 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 have been 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. It is anticipated that this study will continue for two complete production cycles. A Specific Cooperative Agreement, "Development and validation of remote sensing algorithms to detect cyanobacteria in catfish ponds" with the University of Nebraska 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 was formally initiated on May 8, 2001, after review and approval of the formal research proposal by
the Office of Scientific Quality Review. While scheduled to continue through April 30, 2005, it was terminated on December 13, 2004 and replaced by research project #6402-13320-003-00D, "Optimizing Catfish/Water Quality Interactions to Increase Catfish Production on December 14, 2004. While only two scientists worked on this research project, it produced twenty-nine popular articles and presentations and twenty-six scientific articles. One project was awarded an Honorable Mention for Excellence in Technology Transfer, Federal Laboratory Consortium, Southeast Region. Results over the life of the project include (see sections 4A and 4B of previous annual reports for details): An alga, previously thought to be benign, has been associated with a series of fish kills in Mississippi, North Carolina, Texas, and Arkansas. This alga is easily controlled by low copper sulfate additions, providing a simple management remedy for commercial fish farmers. Action Plan Components 2.D.3 and 2.G.1.
An alga capable of anatoxin-a production has been correlated with VTC (visceral toxicosis of catfish) which has killed 30-40% of brood fish during fall and winter in the four-state region. Ongoing research includes exposure of fish to sub-acute doses to reproduce the fish responses; management alternatives will result from this research. Action Plan Component 2.D.3. Catfish fry reared in ponds in which aeration was initiated when the D.O. concentration dropped to 3.0 mg/L consumed 16.7% more feed and had 9.9% higher net production that those in ponds with aeration initiated when the D.O. concentration dropped to 2.0 mg/L. Fingerling producers can increase production by maintaining a minimum dissolved oxygen concentration of 3.0 mg/L in fry/fingerling ponds. Action Plan Components 2.G.2, 3.E.2, 4.A.1 and 5.B.1. Research demonstrated that industry practices do not provide sufficient nitrogen for growth of desirable algae, thereby limiting zooplankton population size in ponds.
Management recommendations for optimal fertilization practices have been assessed on commercial ponds and adopted by fingerling producers locally. Action Plan Component 3.E.2. Research demonstrated efficacy of diuron at controlling target blue- green algae in catfish production ponds as well as in laboratory bioassays. Action Plan Components 6.E.4, 7.C.3 and 7.E.2. A computer-controlled and monitored respirometer has been designed and constructed to use in measuring impacts of sub-lethal oxygen concentrations on catfish respiration. Action Plan Components 4.A.1 and 4. B.1. An industry-wide pond survey using PCR techniques was conducted to assess the distribution toxin-producing algae, determine toxin levels within ponds, as well as the potential for strains within the south to produce toxins. Action Plan Components 2.A.1 and 6.E.2. The presence of toxin-producing algae was documented in a series of fish kills, the causative organisms have been cultured and identified, and twelve
isoforms of the toxic compound have been identified. Action Plan Components 2.D.3 and 2.G.1. Localization of MIB and geosmin has been observed in filet tissue collected during uptake and purging experiments, with highest concentrations corresponding to belly and tail fillet portions. Action Plan Components 7.C.2, 7.D.3 and 7.E.1. A method for assessing off-flavor has been developed using liver tissue instead of muscle tissue and tested using pilot scale experimentation. Action Plan Components 7.C.2, 7.D.3 and 7.E.1. Catfish feed consumption in ponds has been shown to decrease by 6.3% when dissolved oxygen concentrations are allowed to fall to 2.5 mg/L before aeration is initiated. Action Plan Components 2.G.2, 4.A.1, 4.B.1 and 5.B.1. Catfish production in traditional ponds was more than doubled through increased aeration. Action Plan Components 2.G.2, 4.A.1, 4.B.1 and 5.B.1. Aeration with traditional paddlewheel aerators resulted in higher feed consumption and net production in
catfish ponds than aeration with u-tube aerators. Action Plan Components 2.G.2, 4.A.1, 4.B.1 and 5.B.2. Off-flavor was significantly reduced in ponds aerated with u-tubes when compared to ponds aerated with traditional paddlewheels. Action Plan Components 5.B.2, 6.E.4, 7.C.2 and 7.E.2. Research has shown that reworking production ponds every 4-5 years can reduce occurrence of off-flavor in channel catfish. Action Plan Components 6.E.4, 7.C.2 and 7.E.2. Catfish fry ponds require addition of nitrogen rather than only phosphorus as is currently recommended. Action Plan Components 3.E.2 and 5.B.1. Equipment (the sock-saver) to use liquid oxygen while holding catfish in socks overnight prior to sale has been designed built and successfully demonstrated on a commercial farm. The unit has proven successful at increasing D.O. when catfish are crowded in a sock overnight prior to transport to a processing facility in the morning. Action Plan Components 2.G.2, 5.B.2, 5.E.1, 7.A.1 and 7.C.2.
Allowing the dissolved oxygen to fall to 1.5 mg/L before commencing aeration reduced feed consumption by 45.1%, growth by 30.5% and net catfish production by 54.0%; at higher dissolved oxygen concentrations, a net production of 23,547 kg/ha was achieved. Action Plan Components 2.G.2, 4.A.1, 4.B.1, 4.D.2, 5.B.1 and 6.A.2. An alga, previously thought to be benign, has been cultured from series of fish kills in North Carolina, Texas, and Arkansas and identified as a toxin producer. This algae is easily controlled by low copper sulfate additions. Action Plan Components 2.G.1 and 6.E.4. Research has shown that normal industry fingerling production practices do not provide sufficient nitrogen for growth of desirable algae, thereby limiting zooplankton population size in ponds. Action Plan Component 3.E. 2. Research results indicate that fish raised in ponds aerated with traditional paddlewheels consume more feed and have higher production than those aerated with commercially-available
u-tube (sub-stratum) aerators. However off-flavor was significantly reduced in the u-tube ponds. Action Plan Components 4.A.1, 4.B.1, 5.B.2 and 7.E.2. Freshwater drum have been successfully spawned both in open ponds and in laboratory tanks in sufficient numbers to begin field trials of pond culture techniques and efficacy at snail control, but fingerlings have not yet been successfully trained to eat a pelleted diet. Action Plan Components 2.G.1, 3.E.2, 4.D.1 and 6.E.1. Physa snails >6 mm were controlled by freshwater drum, but smaller snails were not. Action Plan Components 2.G.1 and 6.E.1. Snails were significantly reduced (P<0.05) in commercial (0.8 ha) ponds stocked with 50+ g drum, but were not eliminated. Action Plan Components 2.G.1 and 6.E.1. Optimized fertilization procedure for fry ponds has been tested in commercial aquaculture facilities. Action Plan Component 3.E.2. A comparison between instrumental and flavor checkers was strongly correlated (R= 0.9) with a human
detection threshold of 0.10.2 mg/kg for methylisoborneol. Action Plan Components 7.C.2 and 7.E.1. Major accomplishments and impacts realized over the life of the project were: 1) identification of toxic microalgae found within catfish culture systems; 2) an understanding of toxic algal seasonal successional patterns; 3) management recommendations to control toxin production; 4) assessment of remote sensing technologies to detect harmful alga taxa; 5) collaborative efforts with SRRC, NPRU, and Mississippi State University in the field assessment of chemical herbicides for controlling off-flavor producing microalgae; 6) determine the physiological and production impacts of sub-lethal oxygen concentrations on channel catfish; 7) develop and test new equipment and strategies for managing water quality in channel catfish ponds; and 8) develop techniques for reproduction and rearing of freshwater drum as a possible biological control of the rams horn snail, an intermediate host of the
catfish trematode (Bolbophorus confusus). These accomplishments have reduced 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 commercial fish farmer collaborated with the Agricultural Research Service Catfish Genetics Research Unit to develop equipment for the use of liquid oxygen on commercial fish farms. Equipment (the sock-saver) was designed, built, and successfully tested on a commercial catfish farm in east Mississippi during the 2002 growing season. Information on design and operation has been widely disseminated during the past year through trade publications, newsletters, posters, abstracts
and oral presentations to industry groups. This technology is currently being adopted by catfish farmers in Arkansas, Mississippi and Alabama. This project was awarded a 2004 Honorable Mention for Excellence in Technology Transfer, Federal Laboratory Consortium, Southeast Region. Recommendation on oxygen management in catfish ponds have been disseminated to industry 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). Chambers, J.P., Kleinert, D., Carpenter, B., Heffington, J., Minchew, C.D. , Beecham, R.V. 2004. AquaScanner Catfish Sonar: Acoustic Instrumentation for Aquaculture. Mississippi Intellectual Property Forum. Jackson, MS. November 30-December 1, 2004. Zimba, P.V., Weaver, M.A., Sullivan, M.J., Czarnecki, D. 2004. Fatty acid
analyses of eight Craticula cuspidate clones. Phycological Society of America 58th annual meeting. August 8-12, 2004. Williamsburg, VA. Mischke, C. C., Zimba, P.V. 2004. Optimizing Fry Pond Fertilization. Thad Cochran National Warmwater Aquaculture Center Newsletter. 6(1):4, 10.
Impacts
(N/A)
Publications
- Mischke, C.C., Zimba, P.V. 2003. Optimization of channel catfish fry pond fertilization regimes. Aquaculture 233:219-235.
- Zimba, P.V., Rowan, M., Triemer, R. 2004. Identification of euglenoid algae that produce ichtyotoxins. Journal of Fish Diseases 27:115-117.
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Progress 10/01/03 to 09/30/04
Outputs
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 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 MIB-related off-flavor in the Mississippi Delta. Other algae also produce metabolites resulting in off-flavor and unmarketable fish, and yet others produce toxic compounds which cause direct 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 CRIS is to increase production economics from commercial warm water channel 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 channel 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. This project has four specific goals: 1) Determine effects of sub-lethal oxygen concentrations and the modifying influences of various physical, chemical and biological factors on catfish metabolism and respiratory efficiency; 2) Develop and test equipment and management practices to optimize respiratory efficiency (minimize oxygen stress) and intensify production on warm-water fish farms; 3) Identify problematic algal species responsible for secondary metabolite production (including toxic and off-flavor compounds) that impact catfish production; and 4) Identify techniques/technologies for controlling harmful algal blooms, including biocontrol, natural algicidal products, and synthetic herbicides for use in aquaculture systems. Research planned under this CRIS 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. The milestones for the project are: Year 1 (FY 2001) - Build and test laboratory respirometer for measurement of catfish metabolic rate; preliminary tests of sub-stratum aerators and zero-discharge intense aeration catfish production system; equip laboratory with field and laboratory supplies to begin experimentation on diuron efficacy in controlling off-flavor producing algal species; setup HPLC and pulse amplitude fluorescence meter to detect physiological state of algae; assist Dr. K. Schrader with field testing of chemicals for control of off-flavor producing algae. Year 2 (FY
2002) - Determine oxygen consumption rate of USDA-103 channel catfish as affected by ambient oxygen content, temperature, fish size; continue development as indicated by preliminary results on sub-stratum aerators and zero-discharge intensive aeration; initial assessment of companion species; develop Palm-pilot software to allow for the collection and computerization of oxygen data on commercial fish farms; complete experimentation on efficacy of diuron and write up research results; isolate algal clones producing toxins and begin tests in laboratory to assess the environmental cues responsible for toxin production by cyanobacteria; continue collaborative efforts with Dr. K. Schrader in field evaluation of compounds for control of off-favor producing microalgae; setup a CRADA with H. Lynn Walker (Louisiana Tech) to assess biocontrol of off-flavor producing species of algae with his bacteria exhibiting algicidal properties. Year 3 (FY 2003) - Conduct baseline respiratory physiological
comparisons of USDA-103 with other channel catfish lines/strains and hybrids; assess impacts of high CO2/low pH on respiration (Bohr effect) and potential of commercial buffers (hydrated lime and sodium bicarbonate) to modify pond environment; develop techniques for remote sampling of catfish respiratory physiology, including catheters and telemetry; pond trial(s) of promising companion species; establish algal toxin LD50 levels for various catfish growth stages; finalize laboratory assessment and management alternatives for toxin research; initiate field experiments using management recommendations.. Year 4 (FY 2004) - Determine impacts on respiration of various conditions/pathologies proliferative gill disease (PGD or hamburger gill), and methemoglobinemia ("brown blood" disease); further development of remote sampling of catfish physiology with aim of physiological telemetry of free-swimming catfish in a pond environment; final studies on water quality management, companion
species and aeration systems. Year 5 (FY 2005) - Complete studies; finalize recommendations on commercial techniques to most efficiently and economically manage pond oxygen concentrations. 3. Milestones: A. List the milestones that were scheduled to be addressed in FY 2004. How many milestones did you fully or substantially meet in FY 2004 and indicate which ones were not fully or substantially met, briefly explain why not, and your plans to do so. The milestones that were scheduled to be met in FY 2004 include: Determine impacts on respiration of various conditions/pathologies proliferative gill disease (PGD or hamburger gill), and methemoglobinemia ("brown blood" disease); further development of remote sampling of catfish physiology with aim of physiological telemetry of free-swimming catfish in a pond environment; final studies on water quality management, companion species and aeration systems. The basic catfish respiratory physiology was not pursued as initially planned for two
reasons. First, after this CRIS began a graduate student from the University of Mississippi beginning her dissertation at Stoneville chose to study catfish respiratory physiology (Beecham, R.V. 2004. A study of the swimming capabilities of blue, Ictalurus furcatus, and channel, Ictalurus punctatus, catfish. Doctoral Dissertation, University of Mississippi, Department of Biology). Since her focus was also catfish respiratory physiology, we felt that a major duplication of effort in this area would be unnecessary. Second, results from the initial (FY 2001) pond production studies in which dissolved oxygen concentrations were controlled (sub-stratum aerators and zero-discharge intense aeration catfish production system listed in Year 1 Milestones) were so promising that more effort was expended in this area. This research was conducted in 14-acre ponds at the USDA ARS facility in Stoneville as well as in 1-acre ponds at the Delta Western Research Unit in Indianola, MS, through a
contract and collaborative agreement. These experiments have resulted in major new recommendations on oxygen management which are already being disseminated to the industry (see section 7). Major progress has been made on the development and testing of new aeration equipment. The "Sock-Saver", a trailer designed to deliver 150 gallons of liquid oxygen to remote locations on commercial fish farms, is currently being adopted by the industry. This project has been nominated by the Mid South Area for the 2004 ARS Technology Transfer Award. The sub- stratum aerator tested for several years has also proved promising. This work is now being pursued by a Mississippi State University collaborator. A new strategy for aerator placement in large commercial ponds has been developed. This concept will be tested on a commercial farm as a part of our renewed CRIS. The renewed CRIS will also sanction research and development of a commercial-scale u-tube aerator that has been designed in
collaboration with an aerator manufacturer. B. List the milestones that you expect to address over the next three years (FY 2005, 2006, and 2007). What do you expect to accomplish, year by year, over the next three years under each milestone? This project is scheduled for completion on April 30, 2005. The last partial year of this project (Year 5, FY 2005) will be used to both wrap- up this project and transition to the new CRIS (currently under OSCR review) which will be implemented in the middle of FY 2005. The Year 5 milestones for this project are: Year 5 (first half of FY 2005) Complete studies; finalize recommendations on commercial techniques to most efficiently and economically manage pond oxygen concentrations. Assuming that work continues as planned, and the new CRIS project plan is approved as proposed, we anticipate accomplishing in: Year 5 (last half of FY 2005) Complete field data collection for model development, identify unique cyanobacterial reflectance features.
Complete pond scale experiments to assess control of off-flavor algae and determine optimal compound concentrations. Complete laboratory based purging studies, identify bottlenecks and make modifications. Complete collection of baseline data for nutrients and plankton. Determine limiting nutrients favoring cyanobacterial dominance. Complete laboratory bioassays of Microcystis using catfish fingerlings. Bulk culturing of Euglena; serial fractionation. Complete food fish production trials at CGRU and Delta-Western Research Center. Initiate commercial production trials of aerator placement in ten 6.8-ha ponds at Dillard & Company, Inc. Complete construction and testing of prototype powered u-tube aerator. Continue field tests of Aquascanner SONAR at ARS and Harvest Select sites; Determine optimum threshold level and length of signal; Determine error limits; Technology transfer and licensing issues. Begin investigation of alternate transducer materials. Year 6 (FY 2006) Complete second
year field data using modified sensor windows, apply model to data developed for first year (jackknife approach). Complete 2nd year experiments, and begin EPA registry for acceptance of proprietary treatments for commercial use. Complete field based purging studies using laboratory results to calibrate chemical additions. Complete pond treatments to maintain optimal nutrient ratios, monitor nutrients, and plankton. Complete pond treatment to obtain optimal nutrient ratios; monitor ponds for algal composition. Complete laboratory bioassays of Microcystis using adult catfish. NMR, x- ray crystallo-graphy of toxin. Complete 2nd year food fish production trials at CGRU and Delta-Western Research Center. Complete first harvests from commercial ponds in aerator placement study as fish reach market size; restock for second cycle. Complete re-design of phase-II u-tube. Initiate production testing. Modify SONAR use and deployment based on end user feedback; Continue transition to end user.
Fabricate and test sample transducers utilizing new materials. Year 7 (FY 2007) Complete modification of sensor windows as needed to specifically identify off-flavor producing algae, collect field data for verification of method. Complete field trials on use of proprietary chemical treatment for cyanobacteria in commercial pond facilities. Complete optimization of nutrient additions and repeat nutrient additions in TCNWAC ponds. Determine patent potential to euglenoid neurotoxin. Complete fingerling production at low DO to augment research at medium oxygen levels previously completed. Continue second production cycle of aeration placement strategy in commercial ponds (each production cycle may take 12-18 months). Complete production testing and evaluation of u-tube aerator in research ponds. Continue transition of acoustic technology to end user; begin investigation of additional uses of acoustics to improve production. Begin investigation of alternate sonar transmitter board design.
4. What were the most significant accomplishments this past year? A. Catfish fry survival to fingerling stage averages around 60%, and is affected by the availability of natural food resources in the ponds - particularly zooplankton. Research was conducted on the effect of catfish fry pond fertilization to optimize plankton composition in collaboration with Mississippi State University researchers. Industry practices do not provide sufficient nitrogen for growth of desirable algae, thereby limiting zooplankton population size in ponds. Management recommendations for optimal fertilization practices have been assessed on commercial ponds and adopted by fingerling producers locally. Action Plan Component 3.E.2. B. An alga, previously thought to be benign, has been associated with a series of fish kills in Mississippi, North Carolina, Texas, and Arkansas. The causative organism has been identified and cultured; collaborative research with NOAA's Harmful Algal Bloom chemistry staff has
identified a small molecular weight toxic fraction. Identification of the mode of action, toxin identity, and resulting management recommendations during toxic bloom episodes is ongoing from this work. This alga is easily controlled by low copper sulfate additions, providing a simple management remedy for commercial fish farmers. Action Plan Components 2.D.3 and 2.G. 1. VTC, visceral toxicosis of catfish, has killed 30-40% of brood fish during fall and winter in the four-state region. This problem was studied in collaboration with scientists from the MSU College of Veterinary Medicine. An alga capable of anatoxin-a production has been correlated with these events. Ongoing research includes exposure of fish to sub-acute doses to reproduce the fish responses; management alternatives will result from this research. Action Plan Component 2.D.3. Aeration is the second greatest variable expense on commercial catfish farms but is essential for intensive production. Catfish fry were
produced in pond with controlled D.O (dissolved oxygen) concentrations in order to determine their requirements. Catfish fry reared in ponds in which aeration was initiated when the D.O. concentration dropped to 3.0 mg/L consumed 16.7% more feed and had 9.9% higher net production that those in ponds with aeration initiated when the D.O. concentration dropped to 2.0 mg/L. Fingerling producers can increase production by maintaining a minimum dissolved oxygen concentration of 3.0 mg/L in fry/fingerling ponds. Action Plan Components 2.G.2, 3.E.2, 4.A.1 and 5.B. 1. C. Catfish farming is truly a national industry with over 1100 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 (2003) the industry produced over 661 M pounds at a wholesale price of 58.1c/pound, compared to 593 M pounds at 75.1c/pound only three years ago. 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. D. Progress Report: None. 5. Describe
the major accomplishments over the life of the project, including their predicted or actual impact. This CRIS (#6402-13320-002-00D: Optimizing catfish/water quality interactions to increase catfish production efficiency) was formally initiated on May 8, 2001 after review and approval of the formal research proposal by the Office of Scientific Quality Review. The project research will continue through April 30, 2005. Results to date include (see section 4A of previous annual reports for details): Research demonstrated efficacy of diuron at controlling target blue- green algae in catfish production ponds as well as in laboratory bioassays. Action Plan Components 6.E.4, 7.C.3 and 7.E.2. A computer-controlled and monitored respirometer has been designed and constructed to use in measuring impacts of sub-lethal oxygen concentrations on catfish respiration. Action Plan Components 4.A.1 and 4. B.1. An industry-wide pond survey using PCR techniques was conducted to assess the distribution
toxin-producing algae, determine toxin levels within ponds, as well as the potential for strains within the south to produce toxins. Action Plan Components 2.A.1 and 6.E.2. The presence of toxin-producing algae was documented in a series of fish kills, the causative organisms have been cultured and identified, and twelve isoforms of the toxic compound have been identified. Action Plan Components 2.D.3 and 2.G.1. Localization of MIB and geosmin has been observed in fillet tissue collected during uptake and purging experiments, with highest concentrations corresponding to belly and tail fillet portions. Action Plan Components 7.C.2, 7.D.3 and 7.E.1. A method for assessing off-flavor has been developed using liver tissue instead of muscle tissue and tested using pilot scale experimentation. Action Plan Components 7.C.2, 7.D.3 and 7.E.1. Catfish feed consumption in ponds has been shown to decrease by 6.3% when dissolved oxygen concentrations are allowed to fall to 2.5 mg/L before aeration
is initiated. Action Plan Components 2.G.2, 4.A.1, 4.B.1 and 5.B.1. Catfish production in traditional ponds was more than doubled through increased aeration. Action Plan Components 2.G.2, 4.A.1, 4.B.1 and 5.B.1. Aeration with traditional paddlewheel aerators resulted in higher feed consumption and net production in catfish ponds than aeration with u-tube aerators. Action Plan Components 2.G.2, 4.A.1, 4.B.1 and 5.B.2. Off-flavor was significantly reduced in ponds aerated with u-tubes when compared to ponds aerated with traditional paddlewheels. Action Plan Components 5.B.2, 6.E.4, 7.C.2 and 7.E.2. Research has shown that reworking production ponds every 4-5 years can reduce occurrence of off-flavor in channel catfish. Action Plan Components 6.E.4, 7.C.2 and 7.E.2. Catfish fry ponds require addition of nitrogen rather than only phosphorus as is currently recommended. Action Plan Components 3.E.2 and 5.B.1. Equipment (the "sock-saver") to use liquid oxygen while holding catfish in socks
overnight prior to sale has been designed, built and successfully demonstrated on a commercial farm. The unit has proven successful at increasing D.O. when catfish are crowded in a sock overnight prior to transport to a processing facility in the morning. Action Plan Components 2.G.2, 5.B.2, 5.E.1, 7.A.1 and 7.C.2. Allowing the dissolved oxygen to fall to 1.5 mg/L before commencing aeration reduced feed consumption by 45.1%, growth by 30.5% and net catfish production by 54.0%; at higher dissolved oxygen concentrations, a net production of 23,547 kg/ha was achieved. Action Plan Components 2.G.2, 4.A.1, 4.B.1, 4.D.2, 5.B.1 and 6.A.2. An alga, previously thought to be benign, has been cultured from series of fish kills in North Carolina, Texas, and Arkansas and identified as a toxin producer. This algae is easily controlled by low copper sulfate additions. Action Plan Components 2.G.1 and 6.E.4. Research has shown that normal industry fingerling production practices do not provide
sufficient nitrogen for growth of desirable algae, thereby limiting zooplankton population size in ponds. Action Plan Component 3.E. 2. Research results indicate that fish raised in ponds aerated with traditional paddlewheels consume more feed and have higher production than those aerated with commercially-available u-tube (sub-stratum) aerators. However off-flavor was significantly reduced in the u-tube ponds. Action Plan Components 4.A.1, 4.B.1, 5.B.2 and 7.E.2. Freshwater drum have been successfully spawned both in open ponds and in laboratory tanks in sufficient numbers to begin field trials of pond culture techniques and efficacy at snail control, but fingerlings have not yet been successfully trained to eat a pelleted diet. Action Plan Components 2.G.1, 3.E.2, 4.D.1 and 6.E.1. Physa snails >6 mm were controlled by freshwater drum, but smaller snails were not. Action Plan Components 2.G.1 and 6.E.1. Snails were significantly reduced (P<0.05) in commercial (0.8 ha) ponds stocked
with 50+ g drum, but were not eliminated. Action Plan Components 2.G.1 and 6.E.1. Optimized fertilization procedure for fry ponds has been tested in commercial aquaculture facilities. Action Plan Component 3.E.2. A comparison between instrumental and flavor checkers was strongly correlated (R= 0.9) with a human detection threshold of 0.1 - 0.2 mg/kg for methylisoborneol. Action Plan Components 7.C.2 and 7.E.1. Major accomplishments and impacts expected over the life of the project are: 1) identification of toxic microalgae found within catfish culture systems; 2) an understanding of toxic algal seasonal successional patterns; 3) management recommendations to control toxin production; 4) assessment of remote sensing technologies to detect harmful alga taxa; 5) collaborative efforts with SRRC, NPRU, and Mississippi State University in the field assessment of chemical herbicides for controlling off-flavor producing microalgae; 6) determine the physiological and production impacts of
sub-lethal oxygen concentrations on channel catfish; 7) develop and test new equipment and strategies for managing water quality in channel catfish ponds; and 8) develop techniques for reproduction and rearing of freshwater drum as a possible biological control of the ram's horn snail, an intermediate host of the catfish trematode (Bolbophorus confusus). 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 commercial fish farmer collaborated with the Agricultural Research Service Catfish Genetics Research Unit to develop equipment for the use of liquid oxygen on
commercial fish farms. Equipment (the "sock-saver") was designed, built, and successfully tested on a commercial catfish farm in east Mississippi during the 2002 growing season. Information on design and operation has been widely disseminated during the past year through trade publications, newsletters, posters, abstracts and oral presentations to industry groups. This technology is currently being adopted by numerous catfish farmers in Arkansas, Mississippi and Alabama. This project has been nominated by the Mid South Area for the 2004 ARS Technology Transfer Award Program. Recommendation on oxygen management in catfish ponds have been disseminated to industry 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. Torrans, Eugene L. 2003. The effect of dissolved oxygen on production of channel
catfish in ponds - how low should we go? The Catfish Journal. 18(4):10,12. Torrans, Eugene L. 2003. "Role of aeration in catfish production", invited presentation to the Electric Power Associations of Mississippi/Catfish Farmers of Mississippi meeting to discuss the development of off-peak electric rates. Yazoo City, MS, December 12, 2003. Torrans, Eugene L. 2004. "Effect of oxygen management on food consumption, food conversion, growth and production of channel catfish", Invited presentation to the Texas Aquaculture Association 34th Annual Conference and Trade Show, El Campo Civic Center, El Campo, TX, January 20-23, 2004. Torrans, Eugene L. 2004. "Morning dissolved oxygen and catfish production/sock-saver update", Invited presentation to the East Mississippi Agricultural Expo, EMCC - Golden Triangle Campus, Mayhew, MS, January 23, 2004. Torrans, Eugene L. 2004. Photo credits: "Freshwater prawns are a unique product", Mississippi Farm Country, 80(10): 10. Torrans, Eugene L. 2004.
Effect of dissolved oxygen on food consumption, growth, production and food conversion in channel catfish Ictalurus punctatus grown in earthen ponds. Abstract and presentation, Aquaculture 2004 Abstract Book, Page 597, March 1-5, 2004, Hawaii Convention Center, Honolulu, Hawaii. Torrans, Eugene. 2004. Effect of minimum D.O. concentration on channel catfish. NWAC (Thad Cochran National Warmwater Aquaculture Center) News. July. 7(1):10-11. Anon. 2004. Electric cooperatives announce discount for delta catfish growers. The Catfish Journal 18(12):1,14. Simard, Tom. 2004. Aeration cost reduction study. The Catfish Journal 18(7):15.
Impacts
(N/A)
Publications
- Mischke, C.C., Zimba, P.V. 2003. Optimization of channel catfish fry pond fertilization regimes. Aquaculture 233:219-235.
- Zimba, P.V., Rowan, M., Triemer, R. 2004. Identification of euglenoid algae that produce ichtyotoxins. Journal of Fish Diseases 27:115-117.
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Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? Question 1: The main mission of the Catfish Genetics Research Unit has been to improve economically important traits of channel catfish through an applied breeding program that incorporates new biotechnologies and addresses all areas of quantitative and qualitative genetics, reproduction, and molecular and cellular genetics. Genetically improved germplasm will be developed, evaluated, and released to commercial producers. Research areas have been identified through planning sessions with industry, state and federal research, and cooperative extension representatives. These sessions led to the expansion of the Unit mission with the creation of a new production biology CRIS, which began on October 1, 1999. The goal of this new CRIS is to improve production economics from commercial warm water channel catfish ponds through improved water quality management. Two approaches will be used to
accomplish this goal. The first will be the identification and control of nuisance algae, with an emphasis on those groups primarily responsible for off-flavors and toxic blooms. The second approach will focus on the impacts of water quality, particularly low oxygen, on the metabolism, growth and production of channel catfish. It is expected that both approaches will result in improved applied pond management techniques for the industry. 2. How serious is the problem? Why does it matter? Question 2: Economic losses equivalent to 20% of the industry farm gate revenue occur as a result of off-flavor compounds produced by blue-green algae. Toxic microalgae and oxygen depletions caused by bloom die-offs can kill entire ponds of catfish, and therefore can be even more problematic than algae producing off-flavors. The costs of sub-lethal water quality stresses (resulting in reduced growth, food conversion efficiency and/or disease resistance) are not known but are assumed to be
significant. Development of improved management practices will help to solve these costly production problems, increase efficiency and profitability, provide a quality product for consumers, and minimize environmental impacts of aquaculture. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? Question 3: The USDA/ARS national research program is divided into three main areas: 1) animal production, product value, and safety, 2) natural resources and sustainable agricultural systems, and 3) crop production, product value, and safety. Research objectives for the Catfish Genetics Research Unit fall under the animal production, product value, and safety area. The main goal of this research area is to enhance the production, value, and safety of foods and other products derived from animals that have a major impact on the American economy, world markets, and the U.S. balance of trade. Research in the Catfish Genetics Research
Unit is in the aquaculture national program area within animal production, product value, and safety. Aquaculture research for the USDA/ARS focuses on a rapidly growing agricultural segment of the U.S. economy. With increasing seafood demand, declining capture fisheries, and a fisheries trade deficit exceeding $4 billion annually, aquaculture is poised to become a major U.S. growth industry in the 21st century. The continued growth and competitiveness of U.S. aquaculture will be directly related to the resources invested in research and technology development. A strong research and technology development program for U.S. aquaculture, led by the Agricultural Research Service, will offer significant benefits to both producers and consumers by enhancing the production efficiency, profitability, and quality of aquaculture products and systems. Research approaches for the Catfish Genetics Research Unit fall within several areas defined by the USDA/ARS national aquaculture research program:
genetic improvement; reproduction and early development; growth, development and nutrition; aquaculture production systems; and sustainability and environmental compatibility of aquaculture. 4. What were the most significant accomplishments this past year? Question 4: A. Single Most Significant Accomplishment during FY-2003 - Research was conducted to evaluate the effect of minimum dissolved oxygen (D.O.) concentration on catfish food consumption, growth and production. Research was conducted in six 0.25-acre ponds at the Catfish Genetics Research Unit in Stoneville, Mississippi, as well as in fifteen 1.0-acre ponds at the Delta Western Research Center at Indianola, Mississippi, in collaboration with a scientist from Mississippi State University. Allowing the dissolved oxygen to fall to 1.5 mg/L before commencing aeration reduced feed consumption by 45.1%, growth by 30.5% and net catfish production by 54.0%; at higher dissolved oxygen concentrations, a net production of 23,547 kg/ha
was achieved. Preliminary management recommendations are being disseminated to the industry while research continues on this topic. B. Other Significant Accomplishment(s), if any - An alga, previously thought to be benign, has been identified as a toxin producer from series of fish kills in North Carolina, Texas, and Arkansas. The causative organism has been identified and cultured; collaborative research with NOAA's Harmful Algal Bloom chemistry staff has identified three toxic fractions. This algae is easily controlled by low copper sulfate additions. Identification of the mode of action, toxin identity, and resulting management recommendations during toxic bloom episodes may be possible from this work. Catfish fry survival to fingerling stage averages around 60%, and is affected by the availability of natural food resources in the ponds, particularly zooplankton. Research was conducted on the effect of catfish fry pond fertilization to optimize plankton composition in
collaboration with Mississippi State University researchers. Industry practices do not provide sufficient nitrogen for growth of desirable algae, thereby limiting zooplankton population size in ponds. Management recommendations for optimal fertilization practices have been proposed and are currently being verified on commercial aquaculture ponds. Research was conducted for a third year to compare catfish production using either traditional paddlewheel aerators or commercially-available u- tube aerators. Research was conducted in fifteen leased ponds at the Delta Western Research Center at Indianola Mississippi in collaboration with a scientist from Mississippi State University. Results indicate that fish in ponds with traditional paddlewheels consume more feed and have higher production; however off-flavor was significantly reduced in the u- tube ponds. Management recommendations and economic assessments will be available at the completion of the study. Traditional paddlewheel
aerators at times are unable to maintain sufficient dissolved oxygen to support a large concentration of channel catfish. In collaboration with the Mississippi Cooperative Extension Service and a private catfish farm, a small trailer capable of delivering 150 gallons of liquid oxygen to remote sites on channel catfish farms was designed, built and tested. The unit has proven successful at increasing D.O. when catfish are crowded in a sock overnight prior to transport to a processing facility in the morning; preliminary tests have been conducted using liquid oxygen to supplement standard electric paddlewheel aerators for routine aeration of commercial ponds. Results have been disseminated to the industry and the technology is being adopted. C. Significant accomplishments/activities that support special target populations - 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. Of the 1,370
catfish farms in the United States, 38% (515) reported annual revenues of less than $25,000. Although the terms "large" and "small" farms are often used in terms of total acreage involved in aquaculture production, the definition used for farm size should be based on revenue. Research on management of nuisance algae and dissolved oxygen is critical for success of all catfish farms, but particularly smaller farms with a generally narrower profit margin. D. Progress Report: This report serves to document research conducted under a Specific Cooperative Agreement (No. 58-6401-1-020; CRIS 6402-13320-002-03S) which was established on May 2, 2001, under this parent CRIS with a collaborator at Langston University (Oklahoma). The goal of this project was to develop techniques to spawn and rear freshwater drum (Aplodinotus grunniens). Drum feed on mollusks and are being evaluated as a potential control of the ram's horn snail, an intermediate host of the catfish trematode (Bolbophorus
confusus). Drum have been successfully spawned both in open ponds and in laboratory tanks in sufficient numbers to begin field trials of pond culture techniques and efficacy. Fingerling drum trained to eat slow-sink catfish feed did not remain on feed when returned to culture ponds. Subsequent efforts to feed-train fingerlings compared semi-moist and standard extruded pellets. Fingerlings (5 g) were acclimated to eating frozen blood worms; pelleted diets were then exchanged for the bloodworms. No fingerlings were successfully trained to eat the pelleted diet in this series of trials. Fingerling drum (15 g) were stocked in 0.04 ha catfish ponds at 125/ha to control snails. Drum survival ranged from 0-80%. Physa snails >6 mm were controlled by the drum, but small snails were not. Larger fingerlings (50+ g) were stocked in commercial catfish ponds. Drum were stocked at 50/ha in 0.8 ha ponds, and at 33/ha in 0.3 ha ponds. Snails were significantly reduced (P<0.05) in ponds with drum, but
were not eliminated. Results were presented at the Annual Meeting of the American Aquaculture Society in Louisville, KY. This report serves to document the final research conducted under a Specific Cooperative Agreement (No. 58-6402-02-022; CRIS 6402-13320-002- 04S) with a collaborator at Mississippi Valley State University. This SCA was established on June 20, 2002 under this parent CRIS to measure iron concentrations in algal culture and field samples. Literature evidence suggests that trace metal (iron) limitation increases toxin production by toxic cyanobacteria. Iron analyses have been completed on five algal culture studies and indicate little impact on toxin production. This project has been completed and was terminated this FY. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Question 5: This CRIS (6402-13320-002-00D: Optimizing catfish/water quality interactions to increase catfish production efficiency) was
formally initiated on May 8, 2001, after review and approval of the formal research proposal by the Office of Scientific Quality Review. The project research will continue through April 30, 2005. Results to date include: Research demonstrated efficacy of diuron at controlling target blue-green algae in catfish production ponds as well as in laboratory bioassays; A computer-controlled and monitored respirometer has been designed and constructed to use in measuring impacts of sub-lethal oxygen concentrations on catfish respiration; An industry-wide pond survey using PCR techniques was conducted to assess the distribution toxin-producing algae, determine toxin levels within ponds, as well as the potential for strains within the south to produce toxins; The presence of toxin-producing algae was documented in a series of fish kills, the causative organisms have been cultured and identified, and twelve isoforms of the toxic compound have been identified; Localization of MIB and geosmin has
been observed in fillet tissue collected during uptake and purging experiments, with highest concentrations corresponding to belly and tail fillet portions; A method for assessing off-flavor has been developed using liver tissue instead of muscle tissue and tested using pilot scale experimentation; Catfish feed consumption in ponds has been shown to decrease by 6.3% when dissolved oxygen concentrations are allowed to fall to 2.5 mg/L before aeration is initiated; Catfish production in traditional ponds was more than doubled through increased aeration; Aeration with traditional paddlewheel aerators resulted in higher feed consumption and net production in catfish ponds than aeration with u-tube aerators; Off-flavor was significantly reduced in ponds aerated with u-tubes when compared to ponds aerated with traditional paddlewheels; Research has shown that reworking production ponds every 4-5 years can reduce occurrence of off-flavor in channel catfish; Catfish fry ponds require addition
of nitrogen rather than only phosphorus as is currently recommended; and Equipment (the "sock-saver") to use liquid oxygen while holding catfish in socks overnight prior to sale has been designed, built and successfully demonstrated on a commercial farm. Major accomplishments expected over the life of the project are: 1) identification of toxic microalgae found within catfish culture systems; 2) an understanding of toxic algal seasonal successional patterns; 3) management recommendations to control toxin production; 4) assessment of remote sensing technologies to detect harmful alga taxa; 5) collaborative efforts with SRRC, NPRU, and Mississippi State University in the field assessment of chemical herbicides for controlling off-flavor producing microalgae; 6) determine the physiological and production impacts of sub- lethal oxygen concentrations on channel catfish; 7) determine the effects of various pathologies (such as anemia, methemoglobinemia, and proliferative gill disease) on
the respiratory efficiency of channel catfish; 8) develop and test new equipment and strategies for managing water quality in channel catfish ponds; and 9) develop techniques for reproduction and rearing of freshwater drum as a possible biological control of the ram's horn snail, an intermediate host of the catfish trematode (Bolbophorus confusus). 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 do you expect to accomplish, year by year, over the next 3 years? Question 6: Expected research accomplishments for the next three years are: Milestone 1 (12 months) - Utilize laboratory respirometer for measurement of catfish metabolic rate; continue tests of zero-discharge intense aeration catfish production system using fingerlings; conduct preliminary trial of novel aerator placement strategy on a commercial fish farm; identification of
toxin-producing microalgae from catfish ponds; seasonal assessment of toxin producing algae, and management recommendations to minimize occurrence of toxic bloom events in production systems; isolate algal clones producing toxins and begin tests in laboratory to assess the environmental cues responsible for toxin production by cyanobacteria; continue collaborative efforts in field evaluation of compounds for control of off-favor producing microalgae; revise CRIS proposal. Milestone 2 (24 months) - Determine oxygen consumption rate of USDA-103 channel catfish as affected by ambient oxygen content, temperature, gill pathologies; conduct baseline respiratory physiological comparisons of USDA-103 with other channel catfish lines/strains and hybrids; assess impacts of high CO2/low pH on respiration and potential of commercial buffers (hydrated lime and sodium bicarbonate) to modify pond environment; in collaboration with Mississippi State University, conduct preliminary trials of organic
catfish production; continue design and development as indicated by preliminary results on u-tube aerators, zero-discharge intensive aeration, and use of liquid oxygen in catfish culture; conduct initial commercial trial of novel aeration placement strategy; conduct field verification of pond fertilization recommendations to grow catfish fry; and optimize remote sensing sensor arrays for identification of algae within catfish production ponds. Milestone 3 (36 months) - Continue testing commercial applications of u- tube aerators, liquid oxygen, and aerator placement/operation strategies; establish algal toxin LD50 levels for various catfish growth stages; finalize laboratory assessment and management alternatives for toxin research; initiate field experiments using algal management recommendations. 7. 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? Question 7: A commercial fish farmer has entered into a Memorandum of Understanding with the Agricultural Research Service Catfish Genetics Research Unit to develop equipment for the use of liquid oxygen on commercial fish farms. Equipment (the "sock-saver") has been designed, built, and successfully used on a commercial catfish farm in east Mississippi during the 2002 growing season. Information on design and operation has been widely disseminated during the past year through trade publications, newsletters, posters, abstracts and oral presentations to industry groups. This technology is currently being adopted by numerous catfish farmers in Arkansas, Mississippi and Alabama. 8. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed
below). Question 8: Anonymous (from Delta Farm Press). `Cool' new oxygen system for channel catfish. The Wave News Network (www.thewaveonline.com). Feb. 20, 2003. Core, J. Liquid oxygen saves channel catfish during harvest. Agricultural Research. 2003. v. 51(8). p. 8-10. Core, J., Spillman, A. Keeping catfish on consumer's menus. Agricultural Research. 2003. v. 51(3). p. 15-18. Hurlburt, B.E., Brashear, S.S., Zimba, P.V., Li, Q. Development and application of a molecular biological assay for the determination of off- flavor producing organisms in catfish aquaculture. Catfish Farmers of America, Catfish Culture Research Symposium. 2003. Abstract p. 11. Kleinholz, K.W., Luker, G.W., Tang, L. Production of freshwater drum, Aplodinotus grunniens. World Aquaculture Society, Aquaculture America. 2003. Abstract p. 146. Luker, G.W., Kleinholz, C.W., Tang, L. Efficacy of freshwater drum, Aplodinotus grunniens, for controlling snails in channel catfish culture ponds. World Aquaculture
Society, Aquaculture America. 2003. Abstract p. 161. Mischke, C.C., Wise, D.J., Li, M.H., Zimba, P.V. Role of zooplankton in catfish fry culture: summary of NWAC investigations. Catfish Farmers of America, Catfish Culture Research Symposium. 2003. Abstract p. 24. Torrans, E. L. Effect of morning (low) D.O. on water quality, food consumption, growth, production and food conversion in channel catfish. Catfish Farmers of America, Catfish Culture Research Symposium. 2003. Abstract p. 8. Torrans, E. L., Hogue, C.D. Jr., Pilkinton, S. LOX for the socks; reducing weigh-backs with liquid oxygen. Catfish Farmers of America, Catfish Culture Research Symposium. 2003. Abstract p. 54. Torrans, E. L., Hogue, C. D. Jr., Pilkinton, S. Reducing weigh-backs with liquid oxygen. Thad Cochran National Warmwater Aquaculture Center News. 2002. v. 5(2). p. 10-11. Torrans, E. L., Hogue, C.D. Jr., Pilkinton, S. "Sock-Saver" shows promise. The Catfish Journal. 2003. v. 17(10). p. 16-17. Zimba, P.V., Mischke,
C.C., Li, M.H., Grimm, C.C. From fry to fillets: effects of water quality on optimal pond performance. Catfish Farmers of America, Catfish Culture Research Symposium. 2003. Abstract p. 11-12.
Impacts
(N/A)
Publications
- Grimm, C.C., Zimba, P.V. Applications of an Instrumental Method for the Analysis of Off Flavors in Fresh Water Aquaculture. Rimando, A., Schrader, K., editors. American Chemical Society, Washington, D.C. Off-flavors in Aquaculture. 2003. p. 209-222.
- Torrans, E. L., Hogue, C. D. Jr., Pilkinton, S. Providing liquid oxygen to remote sites on commercial channel catfish farms. World Aquaculture Society, Aquaculture America. 2003. Abstract p. 294.
- Towery, S., Zimba, P.V., Zablotowicz, R., Mischke, C.C. Effects of differing irrigation water types on nitrogen fixation in rice fields. 67th Annual Meeting Mississippi Academy of Science. Hattiesburg, Mississippi. 2003. Abstract p. 34.
- Hapeman, C.J., Dionigi, C.P., Zimba, P.V. McConnell, L.L. Agrochemical and nutrient impacts on estuaries and other aquatic systems. Journal of Agricultural and Food Chemistry. 2002. v. 50. p. 4382-4384.
- Torrans, E. L., Hogue, C.D. Jr., Pilkinton, S. The Sock-Saver: A small trailer for providing liquid oxygen to remote sites on commercial channel catfish farms. North American Journal of Aquaculture. 2003. v. 65. p. 260- 265.
- Zimba, P.V., Grimm, C.C. A synoptic survey of musty/muddy odor metabolites and microcystin toxin occurrence and concentration in southeastern USA channel catfish (Ictalurus punctatus Rafinesque) production ponds. Aquaculture. 2003. v. 218. p. 81-87.
- Zimba, P.V., Mischke, C.C., Brashear, S.S. Pond-age water column trophic relationships in channel catfish Ictalurus punctatus production ponds. Aquaculture. 2003. v. 219. p. 291-301.
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Progress 10/01/01 to 09/30/02
Outputs
1. What major problem or issue is being resolved and how are you resolving it? The main mission of the Catfish Genetics Research Unit has been to improve economically important traits of channel catfish through an applied breeding program that incorporates new biotechnologies and addresses all areas of quantitative and qualitative genetics, reproduction, and molecular and cellular genetics. Genetically improved germplasm will be developed, evaluated, and released to commercial producers. Research areas have been identified through planning sessions with industry, state and federal research, and cooperative extension representatives. These sessions led to the expansion of the Unit mission with the creation of a new production biology CRIS, which began on October 1, 1999. The goal of this new CRIS is to increase production from commercial warm water channel catfish ponds through improved water quality management. Two approaches will be used to accomplish this goal.
The first will be the identification and control of nuisance algae, with an emphasis on those groups primarily responsible for off-flavors and toxic blooms. The second approach will focus on the impacts of water quality, particularly low oxygen, on the metabolism, growth and production of channel catfish. It is expected that both approaches will result in improved applied pond management techniques for the industry. 2. How serious is the problem? Why does it matter? Economic losses equivalent to 20% of the industry farm gate revenue occur as a result of off-flavor compounds produced by blue-green algae. Toxic microalgae and oxygen depletions caused by bloom die-offs can kill entire ponds of catfish, and therefore can be even more problematic than algae producing off-flavors. The costs of sub-lethal water quality stresses (resulting in reduced growth, food conversion efficiency and/or disease resistance) are not known but are assumed to be significant. Development of improved
management practices will help to solve these costly production problems, increase efficiency and profitability, and provide a quality product for consumers. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has been assigned? The USDA/ARS national research program is divided into three main areas: 1) animal production, product value, and safety, 2) natural resources and sustainable agricultural systems, and 3) crop production, product value, and safety. Research objectives for the Catfish Genetics Research Unit fall under the animal production, product value, and safety area. The main goal of this research area is to enhance the production, value, and safety of foods and other products derived from animals which have a major impact on the American economy, world markets, and the U.S. balance of trade. Research in the Catfish Genetics Research Unit is in the aquaculture national program area (106) within animal production, product value,
and safety. Aquaculture research for the USDA/ARS focuses on a rapidly growing agricultural segment of the U.S. economy. With increasing seafood demand, declining capture fisheries, and a fisheries trade deficit exceeding $4 billion annually, aquaculture is poised to become a major U.S. growth industry in the 21st century. The continued growth and competitiveness of U.S. aquaculture will be directly related to the resources invested in research and technology development. A strong research and technology development program for U.S. aquaculture, led by the Agricultural Research Service, will offer significant benefits to both producers and consumers by enhancing the production efficiency, profitability, and quality of aquaculture products and systems. Research approaches for the Catfish Genetics Research Unit generally fall within three areas defined by the USDA/ARS national aquaculture research program; genetic improvement, reproduction and early development, and growth, development
and nutrition. 4. What was your most significant accomplishment this past year? A. Research was conducted to evaluate the effect of minimum dissolved oxygen (D.O.) concentration on catfish food consumption, growth and production. Research was conducted in six ponds at the Catfish Genetics Research Unit in Stoneville,Mississippi, as well as in fifteen leased ponds at the Delta Western Research Center at Indianola, Mississippi, in collaboration with a scientist from Mississippi State University. Research demonstrated that increasing the minimum diurnal D.O. from approximately 2.5 ppm to 5 ppm increased feed consumption by 6.4 to 7.6%, with no effect on food conversion. Management recommendations will be available after completion of a second year of research on this topic. B. The presence of toxin-producing algae was documented during a series of fish kills. The causative organism has been identified and cultured; twelve isoforms of the toxic compound have been identified. Culture
experimentation to identify nutrient stress that induces toxin production are ongoing. Management recommendations for management of toxic bloom episodes may be possible from these experiments. Research was conducted for a second year to compare catfish production using either traditional paddlewheel aerators or commercially-available u- tube aerators. Research was conducted in fifteen leased ponds at the Delta Western Research Center at Indianola, Mississippi, in collaboration with a scientist from Mississippi State University. Results from the second year indicated that ponds with traditional paddlewheels consumed more feed and had higher production; however, off-flavor was significantly reduced in the u-tube ponds. Management recommendations and economic assessments will be available at the completion of the third year of research. Catfish fry survival to fingerling stage averages around 60%, and possibly caused by the limited availability of natural food resources in the
ponds-particularly zooplankton. Research was conducted on the effect of catfish fry pond fertilization to optimize plankton composition. Industry practices do not provide sufficient nitrogen and silica for growth of desirable algae. Management recommendations for optimal fertilization practices will result from these studies. The rapid growth of the aquaculture industry during the past 25 years has resulted in little pond management information concerning reworking ponds, and industry practice is to rework ponds when erosion of levees necessitates. In collaboration with scientists from Mississippi State University, research studies sampled ponds ranging in age from 1-25 post construction for normal physical/chemical parameters. Statistical analyses separated ponds into two groupings, with 4-5 years as the break point. These results suggest ponds should be reworked every 4-5 years to minimize off-flavor. Traditional paddlewheel aerators at times are unable to maintain sufficient
dissolved oxygen to support a large concentration of channel catfish. In collaboration with the Mississippi Cooperative Extension Service and a private catfish farm, we developed a small trailer capable of delivering 150 gallons of liquid oxygen to remote sites on channel catfish farms. The unit is now being used/tested to increase D.O. when catfish are crowded in a sock overnight prior to transport to a processing facility in the morning. This technology could greatly reduce mortalities typically seen on commercial catfish farms with current harvest and transport procedures. C. 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. Of the 1,370 catfish farms in the United States, 38% (515) reported annual revenues of less than $25,000. Although the terms large and small farms are often used in terms of total acreage involved in aquaculture production, the definition used for small farms
should be based on revenues. Research on management of nuisance algae and dissolved oxygen is critical for success of all catfish farms. D. Progress Report: A Specific Cooperative Agreement (#58-6401-1-020; CRIS 13320-002-03S) was established on May 2, 2001, under this parent CRIS with a collaborator at Langston University (Oklahoma) to develop techniques to spawn and rear freshwater drum (Aplodinotus grunniens). Drum feed on mollusks and are being evaluated as a potential control of the ram's horn snail, an intermediate host of the catfish trematode (Bolbophorus confusus). Drum have been successfully spawned both in open ponds and in laboratory tanks in sufficient numbers to begin field trials of efficacy. A Specific Cooperative Agreement (58-6402-02-022; CRIS 13320-002-04S) was established on June 20, 2002, under this parent CRIS with a collaborator at Mississippi Valley State University to measure iron concentrations in culture and field samples. Literature evidence suggests that
trace metal limitation increases toxin production by toxic cyanobacteria. Iron analyses have been completed on five culture studies. 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact? This CRIS (6402-13320-002-00D: Optimizing catfish/water quality interactions to increase catfish production efficiency) was formally initiated on May 8, 2001,after review and approval of the formal research proposal by the Office of Scientific Quality Review. The project research will continue through April 30, 2005. Results to date include: Research demonstrated efficacy of diuron at controlling target blue-green algae in catfish production ponds, as well as in laboratory bioassays. A computer-controlled and monitored respirometer has been designed and constructed to use in measuring impacts of sub-lethal oxygen concentrations on catfish respiration. An industry-wide pond survey using PCR techniques was conducted to assess the distribution
toxin-producing algae, determine toxin levels within ponds, as well as the potential for strains within the south to produce toxins. Localization of MIB and geosmin has been observed in fillet tissue collected during uptake and purging experiments, with highest concentrations corresponding to belly and tail fillet portions. A method for assessing off-flavor has been developed using liver tissue instead of muscle tissue and tested using pilot scale experimentation. Catfish production in traditional ponds was more than doubled through increased aeration. In a preliminary study, traditional paddlewheel aerators were superior to u-tube aerators in catfish ponds. Catfish feed consumption has been shown to increase with higher minimum dissolved oxygen concentrations. Major accomplishments expected over the life of the project are: 1) identification of toxic microalgae found within catfish culture systems, 2) an understanding of toxic algal seasonal succession patterns, 3) management
recommendations to control toxin production, 4) assessment of remote sensing technologies to detect harmful alga taxa, 5) collaborative efforts with Southern Regional Research Center, New Orleans, LA, and Natural Products Utilization Research Unit, Oxford, MS, in the field assessment of chemical herbicides for controlling off-flavor producing microalgae., 6) determine the physiological and production impacts of sub- lethal oxygen concentrations on channel catfish, 7) determine the effects of various pathologies (such as anemia, methemoglobinemia, and proliferative gill disease) on the respiratory efficiency of channel catfish, 8) develop and test new equipment and strategies for managing water quality in channel catfish ponds, and 9) develop techniques for reproduction and rearing of freshwater drum as a possible biological control of the ram's horn snail, an intermediate host of the catfish trematode (Bolbophorus confusus). 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 do you expect to accomplish, year by year, over the next 3 years? Expected research accomplishments for the next three years are: Milestone 1 (12 months) - Utilize laboratory respirometer for measurement of catfish metabolic rate; continue tests of u-tube aerators and zero- discharge intense aeration catfish production system; identification of toxin-producing microalgae from catfish ponds; seasonal assessment of toxin producing algae, and management recommendations to minimize occurrence of toxic bloom events in production systems; isolate algal clones producing toxins and begin tests in laboratory to assess the environmental cues responsible for toxin production by cyanobacteria; continue collaborative efforts in field evaluation of compounds for control of off-favor producing microalgae. Milestone 2 (24 months) - Determine oxygen consumption rate of
USDA-103 channel catfish as affected by ambient oxygen content, temperature, fish size; continue development as indicated by preliminary results on u-tube aerators, zero-discharge intensive aeration, and use of liquid oxygen in catfish culture; assess effect of pond age on the development and proliferation of harmful cyanobacteria in production ponds; test herbicides in pond-scale experimentation; determine optimal fertilization practices for raising catfish fry; and optimize remote sensing sensor arrays for identification of algae within catfish production ponds. Milestone 3 (36 months) - Conduct baseline respiratory physiological comparisons of USDA-103 with other channel catfish lines/strains and hybrids; assess impacts of high CO2/low pH on respiration and potential of commercial buffers (hydrated lime and sodium bicarbonate) to modify pond environment; develop techniques for remote sampling of catfish respiratory physiology, including catheters and telemetry; establish algal
toxin LD50 levels for various catfish growth stages; finalize laboratory assessment and management alternatives for toxin research; initiate field experiments using management recommendations. 7. What technologies have been transferred and to whom? When is the technology likely to become available to the end user (industry, farmer other scientist)? What are the constraints, if known, to the adoption durability of the technology? A commercial fish farmer has entered into a Memorandum of Understanding with the Agricultural Research Service Catfish Genetics Research Unit to develop equipment for the use of liquid oxygen on commercial fish farms. While still being tested, this equipment is now being successfully used on a commercial catfish farm in east Mississippi. The Mississippi Cooperative Extension Service is introducing other area farmers to this equipment. 8. List your most important publications and presentations, and articles written about your work (NOTE: this does not
replace your review publications which are listed below) Torrans, E. L. Has the time come for liquid oxygen in catfish ponds? The Catfish Journal. October 2001. 16(2):17, 23.
Impacts
(N/A)
Publications
- Zimba, P.V., Thomson, S. Detection of toxin-producing algae by low- altitude remote sensing methods. 7th International Conference of Remote Sensing in the Marine and Coastal Environment. 2002. v. 7. Paper No. 3-5.
- Bates, T.D., Wolters, W.R., Torrans, E.L. Effect of calcium hardness on growth and survival of fingerling channel catfish (Ictalurus punctatus), blue catfish (I. furcatus), and blue X channel catfish hybrids. Aquaculture 2001, January 21-25, 2001, Lake Buena Vista, FL. 2001. Abstract (and poster) p. 47.
- Torrans, E.L., Bates, T.D., Wolters, W.R. Effects of calcium hardness on blue, channel and blue X channel catfish hybrids. 55th Annual SEAFWA Conference, Louisville, KY, October 13-17, 2001. Abstract p. 9.
- Torrans, E. L. Effect of increased stocking density and aeration on production of channel catfish Ictalurus punctatus in ponds. Aquaculture America 2002, January 27-30, San Diego, CA. 2002. Abstract p. 339.
- Zablotowicz, R.M., Zimba, P.V., Johnson, R. Uptake of 14C- atrazine by the marsh grass Panicum haemitomon. Weed Science Society of America Meeting. 2001.
- Zimba, P.V., Thomson, S. Detection of toxin-producing algae by low- altitude remote sensing methods. 7th International Conference of Remote Sensing for Marine and Coastal Environments, Miami, FL. May 2002. Abstract No. 10-06.
- Zimba, P.V. An update on flavor analysis in farm-raised catfish. Catfish Processors Conference, Mississippi State University, Starkville, MS. November 1-2, 2001. Abstract p. 8.
- Zimba, P.V. Microsporine like amino acids: intercalibration results. Phycological Society of America, Madison, WI. August 4-7, 2002. Abstract p. 178.
- Zimba, P.V., Tucker, C.S., Mischke, C., Grimm, C.C. Short-term effects of diuron on catfish (Ictalurus punctatus Rafinesque) pond ecology. North American Journal of Aquaculture. 2002. v. 64. p. 16-23.
- Nonneman, D., Zimba, P.V. A PCR-based test for detection of cyanobacteria capable of producing microcystins. Journal of Phycology. 2002. v. 38. p. 230-233.
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