Location: Warmwater Aquaculture Research Unit
2019 Annual Report
Objectives
The overall objective of this project is to increase profitability of catfish aquaculture by improving farm-level production efficiency. This will be accomplished by developing new production systems and management practices that allow greater control of the culture environment, with the end result that the genetic potential of catfish can be fully expressed. Studies will also be conducted on the use of ultrasound to kill the intermediate host of an important catfish pathogen and reduce bacterial loads in processing plant cold-water washes. Over the next 5 years, we will accomplish the following objectives:
1) Enhance Control of Pond-Based Ecosystems to Maximize Production and Product Quality.
Sub-objective 1.1 Optimize split-pond design for food-sized catfish aquaculture.
Sub-objective 1.2 Maximize catfish production potential of conventional ponds using intensive aeration.
Sub-objective 1.3 Evaluate management practices to reduce the final size variation resulting from variable growth rates in hybrid catfish.
2) Determine the Suitability and Feasibility of Polyculture or Off-season Production of Other Species Using Catfish Culture Infrastructure.
Work on this objective will focus on developing technologies for production of a secondary, non-catfish species, such as tilapia, in split-ponds. Production of secondary filter-feeding species can potentially increase on-farm profits by generating an additional crop at little extra expense and may improve water quality in split-pond systems by feeding on plankton and detritus that are an oxygen-consuming waste product in catfish monocultures.
3) Develop Acoustic Technology and Methodologies to Improve the Production and Profitability of Pond-based Aquaculture in the United States.
Sub-objective 3.1 Develop and test the potential for control of ramshorn snails in ponds using ultrasound.
Sub-objective 3.B. Develop and test the potential for ultrasound to reduce bacteria in the cold-water wash in processing plants.
Work on this objective will be conducted using congressionally mandated funds administered through Specific Cooperative Agreement 58-6402-9-427 (“Development of Active and Passive Acoustic Measurements to Improve Production and Profits of U.S. Aquaculture”) between the ARS Warmwater Aquaculture Research Unit, Stoneville, MS, and the National Center for Physical Acoustics, at the University of Mississippi. Under this Agreement and as part of this Project Plan, novel application of acoustic technology will be tested and developed, including Sub-objective 3.A, developing and testing the potential for control of ramshorn snails (a disease vector in catfish ponds) using ultrasound, and Sub-objective 3.B, reducing bacteria in the cold-water wash in catfish processing systems using acoustic cavitation.
Approach
Four, 7-acre earthen ponds at the National Warmwater Aquaculture Center at Stoneville, Mississippi, will be modified into split-ponds (Sub-objective 1.A). Pump-performance curves will be developed by systematically changing pump operational parameters for four pump types—one pump for each split-pond. High aeration rates will be used to culture hybrid catfish (channel catfish x blue catfish) and measured variables will include fish growth, survival, production, processing yield, feed conversion ratio, dissolved oxygen concentrations, and water quality variables measured biweekly. Relationships among average flow rate (pump type) and fish growth, feed conversion ratio, and selected water quality variables for each year over the 3-year study will be assessed using regression analysis and results will yield different options for farmers using this technology in the industry.
Six, 0.25-acre ponds with 24 horsepower/acre of aeration for hybrid catfish production will be used in this study (Sub-objective 1.B). Dissolved oxygen, temperature and aerator status will be continuously monitored and the aerators controlled using a pond oxygen monitoring and control system already in place. Water quality will be measured biweekly for hybrid catfish production. Response variables will include final fish weight, weight gain, net production, processing yields, survival, feed consumed, feed conversion ratio, aerator usage), and economics Relationships among stocking rate, aerator usage, feed consumed, weight gain, feed conversion ratio, and selected water quality variables will be assessed using regression analysis. This model should allow us to recommend a stocking rate that will allow satiation feeding through the growing season and will be tested on commercial ponds.
Twelve, 1-acre ponds (10-hp of aeration per acre) will be used to produce hybrid catfish at the Delta Branch Experiment Station, Stoneville, MS (Sub-objective 1.C). Production parameters, coefficients of variation in size, and final economics will be compared among treatments using analysis of variance. Pending the results from this study, further studies on hybrid catfish foodfish management practices to reduce growth rate variation, including feeding schedules and practices, will be conducted.
For Sub-objective 2, a 4.5-acre split-pond aquaculture system located at the National Warmwater Aquaculture Center in Stoneville, Mississippi will be modified for to allow for the production of hybrid catfish and Blue Tilapia. Production performance will be measured and a performance average will be taken after three production seasons and a partial budget developed to measure gauges of economic efficiency of this production method as compared to conventional split-pond catfish aquaculture.
Experiments will be conducted on groups of snails using a commercially available sonicator as the acoustic source to destroy snails (Sub-objective 3.A). The potential use of ultrasonic cavitation to reduce bacteria in the cold-water wash in processing plants will be investigated as well in Objective 3.B. A cost-benefit comparison must be made to determine if the proposed design and technique is warranted.
Progress Report
This is the final report for Project 6066-13320-005-00D “Water quality and production systems to enhance production of catfish” which was initiated on 11/3/2014 and is scheduled to terminate on 11/2/2019. This project also included research conducted under University of Mississippi SCA 58-6402-4-036, “Develop acoustic technology and methodologies to improve the profitability of aquaculture in the United States”. The focus of this project was to develop a more complete understanding of the impacts of water quality on growth and production of channel and hybrid catfish, and to develop new equipment, production systems and management strategies to utilize that information.
Agricultural Research Service (ARS) scientists at Stoneville, Mississippi, participated in two regional projects aimed at reducing the production costs for U.S. fish farmers. One of these projects compared on-farm production and economics of intensively aerated ponds, in-pond raceways, and split ponds. The in-pond raceway had the greatest investment cost, followed by intensively aerated ponds, and then split ponds. Operating costs were greatest for the split ponds. Total fixed costs were greatest in the in-pond raceway systems. Overall, profits were greatest in split ponds, followed by intensively aerated pond. In-pond raceways showed losses. Investment analysis suggested economic feasibility of intensive-aeration and split-pond systems under conservative market conditions. However, the yields from in-pond raceways were not sufficiently high to cover the associated high fixed costs, resulting in higher production costs and economic infeasibility. Intensively aerated ponds and split ponds are being recommended to farmers who wish to increase production.
In the second regional project, ARS scientists in Stoneville, Mississippi, evaluated four pumping systems for use in split-ponds: a) 6-hp slow-turning paddlewheel, b) a 10-hp fast-turning paddlewheel, c) a 10-hp high-speed screw pump, and d) a 15-hp high-speed turbine. The slow-turning paddlewheel was much more efficient than the other pumps and had the highest pumping rates but was the most expensive system. Pumping efficiency for the slow-turning paddlewheel was strongly dependent on rotational speed, with increasing efficiency up to a point (2 rpm) and then decreasing after that. The screw pump was the least expensive system to install but had the lowest pumping rate and the second-lowest pumping efficiency. The axial-flow pump was the least efficient pump tested and had the second lowest pumping rate. The fast-turning paddlewheel had the second-best pumping efficiency and pumping rate, but the large-diameter culverts required in the systems made it the second most expensive system to install. Ponds with the highest pumping rates (slow- and fast-turning paddlewheels) had higher net fish production (average = 16,158 lb/acre) and the best feed conversion (average = 1.92) and survival (average = 92%). Split ponds with the lowest pumping rates (screw and turbine pumps) had lower production (average = 13,970 lb/acre) and worse feed conversion (average = 2.11) and survival (average = 87%). Most farmers are now using one of the pumping systems evaluated by Agricultural Research Service scientists.
A study conducted with hybrid catfish determined that food size fish missed at harvest do not cannibalize restocked fingerlings. This eliminated a concern with single-batch production of hybrid catfish.
ARS scientists in Stoneville, Mississippi, collaborated with Mississippi State University scientists, on a project designed to minimize production of catfish larger and smaller than the preferred size range of processors (1-4 pounds). The study examined the impact of partially harvesting or larger fish once during the growing season. Partial harvesting did result in less large and small fish, but overall production was also reduced. However, this technique did provide some cash flow during the summer when feed purchases are high.
A study comparing growth and size distribution of graded and un-graded hybrid catfish demonstrated that stocking graded fingerlings is an effective method to reduce final size distribution of food-size fish. ARS scientists at Stoneville, Mississippi, found that food conversion and mean weight at harvest were not affected by grading fingerlings. However, the proportion of fish above and below the processor-preferred size range was decreased when fingerlings were graded.
While size variation in fingerlings has a great impact on food fish size variation, little research has been done on factors resulting in size variation in pond run fingerlings. ARS scientists at Stoneville, Mississippi, conducted a study to determine the variation in fry size based on the age of the female brooder and the age of swim-up fry. Spawns from each of two, three and four-year-old channel catfish female brooders were collected and incubated in the hatchery. Samples of sac fry, and two-, four-, and six-day-old swim-up fry were collected to determine average wet- and dry-weights, and within spawn variation based on individual wet weights of 100 fry per spawn. Farmers may be able to minimize the size range of fingerlings by stocking more uniform fry.
ARS scientists at Stoneville, Mississippi, previously determined that channel catfish egg masses require ambient water with over 95% air saturation to maintain optimum development. Since hybrid catfish eggs are often incubated as loose eggs in large vertical tube incubators, it was assumed that the oxygen requirement was lower. A study conducted by ARS scientists in Stoneville, Mississippi, determined that the maximum dissolved oxygen (DO) required by hybrid catfish eggs peaked at 79% air saturation during the last two days of incubation. It is recommended that managers maintain DO above 80% during the last two days of incubation.
There is renewed interest in 6-phytase “super-dosing” in animal feeds. It was believed that phytase super-dosing may help alleviate losses associated with catfish anemia, a major disease in catfish. Two experiments were conducted by ARS scientists at Stoneville, Mississippi, in collaboration with scientists from Mississippi State University to evaluate responses of hybrid catfish to “super-dosing” of 6-phytase. Phytase super-dosing does not appear to have additional benefits beyond the standard dose, and also had no beneficial effects on water quality. Ongoing technology transfer efforts recommend 500 FTU/kg phytase and not “super-dosing” to replace inorganic phosphorus in catfish feeds.
Most catfish research has been conducted in small (0.10-0.25-acre) ponds. It is assumed that farmers will observe the same relative results in larger (0.3-20-acre) commercial ponds. ARS scientists in Stoneville, Mississippi, with collaborators from Mississippi State University, produced hybrid catfish at two stocking rates in small, medium and large earthen ponds. Results, when available, will shed light on the application of small-pond research to commercial ponds.
ARS researchers at Stoneville, Mississippi, have developed a new aerator, the Power Tube Airlift (PTA) which can concentrate DO into a small zone of water in a pond using less energy than traditional methods. This invention was granted a patent with the U.S. Patent and Trademark Office (Patent No. 8,919,744 B1, December 2014, "Water Aeration System and Method").
A study was completed with hybrid catfish at stocking rates ranging from 6,000/acre to 36,000/acre. Dissolved oxygen was controlled above 3.0 ppm. Production was 35,674 pounds per acre at the highest stocking rate and food conversion ratio averaged 1.84 overall. No water quality parameters reached critical levels. It appears that volatization of ammonia at high aeration rates and nitrification by bacteria at high feeding rates limited the ammonia concentrations at high density/aeration rates/feeding rates.
Numerous pond studies have demonstrated that low dissolved oxygen concentrations result in lower feed intake, growth, and production in catfish. A project was conducted by ARS scientists in Stoneville, Mississippi, to understand the physiological mechanisms that impact appetite/feed intake in channel catfish during periods of low dissolved oxygen. Several neuropeptides were suspected to be involved in the control of appetite in catfish. Scientists have completed individual gene measurements at different time points and have identified conditions that increase gene expression of neuropeptides. These studies may lead to a more efficient selection of fish based on the individual gene expression of critical neuropeptides rather than mass selection from long-term pond production studies.
Split ponds use screens to prevent the movement of fish between the two sections. The screens themselves restrict the water flow, and collection of grass clippings, weeds and other debris on the screens restrict it further. Scientists at the University of Mississippi in Oxford, Mississippi, began studying the possible use of acoustic stimuli as deterrents to fish movement between the pond sections. A system was assembled to generate sounds and simultaneously record the sound levels at multiple locations within the pond. The propagation data was analyzed, and appropriate sound levels were determined that should be audible by fish but not harmful. A hardware system was assembled and tested to generate a variety of sounds in a pond and monitor fish movement within a small area. The system was tested in stocked split ponds. Some of the acoustic stimuli tested elicited a measurable fish response.
Accomplishments
1. Impact of female brooder on size variation of fry. While size variation in fingerlings has a great impact on food fish size variation, little research has been done on factors resulting in size variation in pond run fingerlings. ARS scientists at Stoneville, Mississippi, conducted a study to determine the variation in fry size resulting from the age of the female brooder and the age of swim-up fry.
Ten spawns from each of two, three and four-year-old channel catfish female brooders were collected and incubated in the hatchery. Samples of sac fry, and two-, four-, and six-day-old swim-up fry were collected to determine average wet- and dry-weights, and within-spawn variation based on individual wet weights of 100 fry per spawn.
The weight of sac fry and swim-up fry at all ages was less for offspring of two-year-old females, and higher and generally similar for offspring of three- and four-year-old females. The coefficient of variation (CV) in weight increased with fry age among all female-age groups but was greater for all ages of fry for offspring of two-year-old females. Mixing eggs or sac fry from different age females or mixing fry of different ages post swim-up prior to stocking will increase size variation of stocked fry. Any initial variation in size of fry stocked will likely be magnified when fry are stocked in ponds with mixed-size zooplankton populations. It is possible to reduce catfish fingerling size range by stocking only fry of the same age post-hatch and from the same age female brooder in each fry pond. This may reduce the need to grade fingerlings before sale.
Review Publications
Tucker, C.S., Mcnevin, A., Torrans, E.L., Bosworth, B.G. 2019. Catfishes. In: Lucas, J.S., Southgate, P.C., Tucker, C.S., editors. Aquaculture: Farming Aquatic Animals and Plants. West Sussex, UK: John Wiley & Sons Ltd, West Sussex. Book Chapter. P. 415-436.
Boyd, C.E., Tucker, C.S. 2019. Water quality. In: Lucas, J.S., Southgate, P.C., Tucker, C.S., editors. Aquaculture: Farming Aquatic Animals and Plants. West Sussex, UK: John Wiley & Sons Ltd, West Sussex. Book Chapter. P. 63-92.
Boyd, C.E., Mcnevin, A.A., Tucker, C.S. 2019. Resource use and the environment. In: Lucas, J.S., Southgate, P.C., Tucker, C.S., editors. Aquaculture: Farming Aquatic Animals and Plants. West Sussex, UK: John Wiley & Sons Ltd, West Sussex. Book Chapter. P. 93-112.
Hargreaves, J., Brummett, R., Tucker, C.S. 2019. The future of aquaculture. In: Lucas, J.S., Southgate, P.C., Tucker, C.S., editors. Aquaculture: Farming Aquatic Animals and Plants. West Sussex, UK: John Wiley & Sons Ltd, West Sussex.Book Chapter. P. 617-636.
Lucas, J.S., Southgate, P.C., Tucker, C.S. 2019. Aquaculture: Farming aquatic animal and plants. West Sussex, UK: John Wiley & Sons Ltd. Book Chapter. P. 642.
Li, M.H., Wise, D.J., Mischke, C.C., Aarattuthodiyil, S., Tiwari, A., Lucas, P.M., Tucker, C.S., Torrans, E.L., Perera, T.D. 2019. Pond-raised hybrid catfish, male Ictalurus punctatus X female Ictalurus furcatus, do not respond to microbial phytase “super-dosing”. Journal of the World Aquaculture Society. 50:78-86.
Kumar, G., Engle, C., Hanson, T., Tucker, C.S., Brown, T., Bott, L., Roy, L., Torrans, E.L., Boyd, C., Recsetar, M., Park, J. 2018. Economics of alternative catfish production technologies. Journal of the World Aquaculture Society. 49:1039-1057.
Mischke, C.C., Wise, D.J., Tucker, C.S., Griffin, M.J., Baker, B.H., Greenway, T.E., Byars, T.S., Tiwari, A. 2019. Copper sulfate pre-treatment for snail control reduces channel catfish survival. North American Journal of Aquaculture. 81:160-168.
