Progress 06/01/14 to 01/31/16
Outputs
Target Audience:The target audience reached by this effort include commercial fish farmers in Arkansas and state game and fish agencies interested in split pond production systems. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?The field work component of the project was completed in December 2015 due to a number of delays which were previously mentioned. Hence, dissimination of information to interested parties has just recently started. A presentation was given on the project to farmers and university researchers at the 2016Arkansas Bait & Ornamental Fish Growers Association Workshop in Lonoke on February 11, 2016. The talk generated quite a bit of interest and questions from the audience. In addition, farmers and researchers from both Arkansas and Mississippi have visited our farm to examine the baitfish split pond that was constructed. These efforts will be continued in 2016 as we run additional pilot trials with the system prior to submission of a Phase II proposal. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
With the success of SPS in catfish industry, we have paid a great deal of attention to the SPS for baitfish culture due to many desirable benefits, such as intensification, intensive management, improved inventory control, desirable anti-predation attributes, and effective disease treatment. Thus, our primary goal in this project was to develop a new split pond system and management/operation criteria for baitfish, specifically fathead minnows and to evaluate economic feasibility. We developed a 9.4 acre pond split pond system with a UAPB type water circulator and two rotary screen fish barriers to retain small fish. The pond consisted of a fish basin (0.94 acre) and a waste treatment basin (8.46 acre). Two culverts connected the basins divided by an earthen levee. A water circulator was placed in the waste treatment side and the two fish barriers were mounted in the fish basin side. We conducted a fathead minnow study to compare growth performance between split and traditional ponds and also economic analyses. Juvenile fathead minnows were stocked in the split pond at a rate of 153,948 fish/acre on September 3, 2015. A traditional pond (9.4-acre) was stocked with fathead minnows at a rate of 148,000 fish/acre. Fish were harvested three times on October 16 (partial harvest), November 5 (partial harvest), and December 10, 2015 to estimate survival and productivity. Total fish number harvested during the period appeared to be higher in the split pond. This might be attributed to the higher initial stocking rate. Overall gross yield and survival rate were, however, higher in the traditional pond. Fathead minnows in the two production systems progressively grew in body length and individual weight. Overall, growth rate in the traditional pond was higher than that in the split pond so that fish in the traditional pond were larger than those in the split pond at the end of study. The condition factor was higher in the traditional pond than the split pond, but there was no significant differences between the two production systems. Variations in the body length, weight, and condition factor were initially greater in the traditional pond, but became smaller with the course of time, and were similar at the end of study. Complete enterprise budgets were developed for production of fathead minnows using standard budgeting principles and methods. Separate budgets were developed for: 1) traditional ponds; and 2) the newly-constructed split-pond system. In the economic analysis, the returns with a 10 acre split pond were sufficient to cover all variable costs but not all the fixed costs. The lower yield from the split pond was not sufficient to cover the additional annual fixed costs that resulted from conversion of two 5-acre ponds to a single, 10-acre split pond. Thus, in comparison to the traditional pond, net returns from the split pond were lower than those in the traditional ponds. This was primarily due to the lower yield of fathead minnows in the split ponds, combined with the increased annual fixed costs resulting from the additional investment. However, breakeven yields above total costs for the 10-acre split pond were 401 lb/ac. This is a level of yield that is commonly attained in minnow ponds. Given that the yields used in the economic analysis (302 lb/ac) were from a single observation, it would be worthwhile to run the split pond for another season to obtain yield estimates from more than one observation. If yields of at least 401 lb/ac could be achieved, then the split-pond system for fathead minnows would be economically feasible (profitable over the long-term, after accounting for all costs that include non-cash costs of depreciation and opportunity costs on the investment capital). The additional investment in the split-pond system would need to be accompanied approximately by an additional 50 lb/ac of fathead minnows to result in the same level of economic returns as in traditional minnow ponds. During this project, the water circulator and fish barriers were successfully operated with minimal daily management. The water circulator was properly designed, enabling to pump water at different flow rates with an appropriate range of power consumption. One of the most important outcomes of this project was to develop the rotary disc screen fish barrier. The fish barrier was successful in retaining fish without serious operational and/or biological problems (mechanical jams, breakages, bio-fouling, and/or damage to fish due to disc rotation), allowing for sufficient water flow. This implies that the use of this type of fish barrier could be expanded to fingerlings production of other species, bringing an impact to other aquaculture industries. Although the production study did not indicate better performance of split pond with fathead minnows compared to a traditional pond approach, it might be too early to conclude the feasibility of the split pond based on the result. The lower production in the split pond might be attributed to the crowding effect and/or some other factors. Moreover, this study was conducted in late fall and we did not provide fish with optimal growing conditions during the summer and early fall when zooplankton abundances are much higher. In the smaller fish basin, the crowded fish were not provided with enough natural food that is a major food source for fathead minnows. Albeit with the lower production rate in this short study with the split pond, anticipated advantages of the SPS should not be taken lightly. If properly used, the application of SPS to batfish culture could, to a large extent, enhance our production and business regimes. This is supported by the economic analyses. In the economic analyses, breakeven yields above total costs for the 10-acre split pond were 401 lb/ac. This is a common level of yield easily attainable in fathead minnow ponds. Moreover, there are some potential advantages of split-pond systems that were not accounted for in this preliminary, proof-of-concept trial. Confining minnows to a smaller portion of a pond system would allow for better protection from losses due to bird depredation that have been shown to cause substantial economic losses on minnow farms. The survival of fathead minnows in split ponds also indicates that this system that includes a smaller fish containment section could be used feasibly to hold "weigh-back" fish that are returned following harvesting and attempted delivery without mixing with other sizes of fish. Thus, information and data derived from this study could enable Arkansas's baitfish farmers to cope with the problems that they have faced for a long time. In addition to helping baitfish farmers, the results of this study will also help other fingerling producers improve the profitability and sustainability of their operations, thus ensuring their future survival.
Publications
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Progress 06/01/14 to 05/31/15
Outputs
Target Audience:
Nothing Reported
Changes/Problems: There have been no majors changes in approach for this project. The only change is that we filed a no-cost extension to complete the project. Due to circumstances beyond our control, we have a late start on the project. We did not receive the funding to start the project until the first of October of 2014. The production season for raising fathead minnows is late spring through fall and we were beyond that window prior to receiving the grant funds. Prior to receiving funding in the fall we did go ahead and accomplish the dirt work to modify an existing 5 acre pond into a split pond system. However, we are still in the process of building and fabricating components of the split pond system that will be installed in the modified pond and used to conduct the study. Fabrication and installation of components of the split pond system will be completed by April of 2015 (Objective 1 and 2). The plan is to stock fish in the split pond system in April of 2015 and harvest in November of 2015 (Objective 3). Thus, we are requesting a no-cost extension be granted until January 31 of 2016 to provide sufficient time to analyze the collected data, conduct an economic analysis (Objective 3) and prepare our report. The engineering design work for Objective 1 (and nearly completed for objective 2) has been completed by the subcontractors at the University of Arkansas at Pine Bluff and we are using this information in the fabrication and installation process. What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals? 2) Objective 2: Development of fish barriers to retain small baitfish in fish basin We are in the process of meeting the goals of Objective 2. Prior to fabricating rotary screen fish barriers (RoSFiB), we collaborated with UAPB personnel to develop an engineering design of fish barriers based on operational parameters such as rotational speed and required surface area of rotary screen. Considering the maximum pond water depth (1.22 m or 4 ft), the diameter of prototype RoSFiB were initially set at 8 ft in order to maximize the immersed surface area of screen. With the precondition, the effective submerged area, rotational speed and diameter of the rotary screen fish barrier were determined using an engineering equation developed by Boucher (1947) as follows.\ Equation 4 Also, rotational speed of RoSFiB can be estimated with the Equation 4 considering the effective submerged area, submerged surface area, and speed of strainer. Equation 5 Based on the rotational speed, torque (N-m) applied for motor and shaft can be derived by the following equation. Consequently required horse power of a motor and diameter of shaft can be estimated using torque. Each engineering parameter is summarized in Table 6. As the parameters are not well defined for our application (not for filtering uses), those were derived to our best knowledge and estimations considering similar applications. Equation 6 Pfb (motor power, hp) = (RPM T)/7161.75 Equation 7 Table 6. Values of engineering parameters applied for rotary screen fish barriers. Parameter Value Remark Precondition of rotary screen feature - Diameter (D, m) 2.43 (8 ft) - Submergence (%) 40 - Submerged surface area (Sa, m2) 2.26 (26.4 ft2) - Screen mesh size (mm) 3.18 (1/8 in) - Screen void ratio (%) 50 Defining engineering parameters for approximation of effective submerged area and rotational speed of rotary screen 1) m (constant) 0.0267 The values applied were referred by Ali (2013), best knowledge, and observations. 2) Q (water flow, m3/min) 25.7 (6,807 gpm) 3) Cf (initial resistance of clean filter mesh, m) 0.017 4) n (constant) 0.1337 5) I (filterability index, m-3) 0.05 6) s (Speed of strainer, m2/min) 2.4 7) Coefficient of discharge (unitless, clean screen) 0.6 8) Hscreen (friction head loss by screen, m) 0.2 Defining engineering parameters for approximation of effective submerged area and rotational speed of rotary screen 1) Expected weight of rotary screen (W, kg) 500 2) Inertia of a solid shaft (Is, kg-m2) 739 Is= W•(D/2)2 3) Angle acceleration (Aa, rad/sec2) 0.40 Aa= D•(RPM/60) 4) Maximum yield stress of shaft (Mpa) 3,600 Regular A36 steel shaft 5) Maximum yield stress of shaft (N/m2) 248,211,262 6) Safety factor (fraction) 4 Outdoor and continuous application 8) Allowable shear stress (N/m2) 62,052,816 Table 7. Results of estimating required rotational speed of rotary screen and sizing of a motor and shaft diameter Parameter Value Remark Approximation of effective surface and rotational speed of rotary screen - Required effective surface area (m2) 8.2 Equation 4 - Required rotational speed (rpm) 3.9 Equation 5, Adjustable rpm range: 0- 7.5 rpm - Torque (N-m) 1,195 Equation 6 Approximation of driving motor size and shaft diameter - Required minimum horse power of driving motor (hp) 0.16 at 3.9 rpm 0.61 at 7.5 rpm Equation 7.Using a variable frequency drive, rotational speed will be adjusted up to a maximum rpm of 7.5 in order to ensure enough water flow rate as needed. - Required minimum driving shaft diameter (Sdf, cm) 2.9 (1.14 in) at 3.9 rpm 3.6 (1.43 in) at 7.5 rpm Equation 3. To allow the motor and shaft to withstand force at the maximum rpm, we determined to install a 1 hp motor and a 1.43 cm (1-7/16 in) shaft. In order to understand the extent of bio-fouling to different mesh size of the screen for future application to smaller fish, UAPB personnel are modifying the standard filterability index apparatus proposed by Boucher (1947). The test apparatus will be made with 5 cm (2 in) transparent PVC pipes, and consists of a U-shaped flow mesh sizes of screen and hydraulic loading rates. The experimental mesh size of the channel, control valves, a flow meter, and a manometer. Pond water will be injected onto the side of one end of the U-shaped flow channel and pass through a screen mesh vertically mounted in the middle of the flow channel. As the water passes through the channel and the screen mesh, the changes of water head in the channel will be measured over time, based on the different screen will be 1/16 and 1/8 inches, and the experimental hydraulic loading rates will be set at 10, 20, and 30 m3/m2 min-1. The UAPB personnel are also currently fabricating fish barriers based on the engineering design in collaboration of our manufacturing team in real time. Up to date, fabrication is 70% complete and will be finished by the end of February, 2015. Objective 3 When we complete the fabrication of the paddlewheel water circulator/fish barriers and the construction of split pond by the mid-March, we will stock 100,000-150,000 young fathead minnows/acre in the pond (total 500,000-750,000 in the fish basin) in mid-April. The fish will be raised in this environment until early-November. In order to evaluate the growth performance of the fathead minnows, at the end experiment, we will measure total weight, survival rate, and feed conversion along with size variation. The fish basin will be netted during the experiment to protect fish from bird predation and survival rate will be compared to control ponds. This information will provide us with practical measurements that we can use to compare the productivity, inventory control, and anti-predation capability of the split pond against traditional ponds. In addition, over the course of the growth study, we will routinely collect water and examine the water quality in the fish and waste treatment basins. Dr. Roy will assist us with the overall data collection throughout the production period and Dr. Nathan Stone will consult with general management of fathead minnow culture in the SPS. We will use standard farm management principles and collected data to develop variable and fixed cost of production estimates for each crop of baitfish produced in the SPS. This will allow us to compare costs of raising fish in split ponds to historical production of baitfish in traditional earthen ponds at our facility. Variable costs for each crop will include those for fingerlings, feed, electricity, chemicals, labor, equipment maintenance, and interest on operating costs, etc. Fixed costs will be based on the initial construction costs of the split pond system. An enterprise budget covering these costs will be developed and compared. All economic analyses will be conducted by Dr. Roy and Dr. Carole Engle (Professor of Aquaculture Economics/Director at UAPB). Data to be used in the analysis will be collected by Dr. Roy and farm personnel. This analysis will be invaluable for development of the commercialization plan and expansion required during Phase II.
Impacts
What was accomplished under these goals?
1) Objective 1: Development and performance evaluation of a water circulator Considering biological and engineering preconditions for the application of the UAPB water circulator to baitfish culture, we collaborated with UAPB personnel to configure the setup of a split pond and develop an engineering design for a water circulator optimized for baitfish culture. The cultural and biological preconditions applied for this project are listed in Table 1 and 2. Table 1. Precondition of experimental pond configuration and culture management Pond Feature Culture management Pond size (ha) 2.02 (5 acre) Stocking density (fish/ha) 372,000 (150,000/ha) Fish basin ratio (%) 10 Total number of fish stocked 750,000 Water depth (m) 1.22 (4 ft) Harvest size (fish/kg) 318 (143/lb) Fish basin area (acre) 0.202 (0.5 acre) Survival rate 70 Fish basin water volume (m3) 2470.5 (652,643 gal.) Feeding ration (% of total body weight) / Protein content (%) 2 / 28 Table 2. Theoretical oxygen consumption and ammonia excretion rates Item Value Remark Daily oxygen consumption (DOC, g O2/day) 1,152 DOC = 36% of daily feeding rate (Tucker and Hargreaves 2004) Net protein utilization ratio (NPU) assumed 0.2 DAE (g/day) = (1 - NPU) x (protein fraction / 6.25) x 1000 x total daily feed amount (Tucker and Boyd 1985) Daily ammonia excretion rate (DAE, kg TAN/day) 1.14 With respect to the theoretical oxygen consumption and ammonia excretion rates, minimum required water flow rate was estimated using Mass Balance Analysis (Table 3). As a result, more water flow rate was required for ammonia removal than oxygen supplementation and the minimum water flow required for a baitfish split pond was approximated to be 25.96 m3/min (6,800 gallon/min) at the given preconditions. At the water flow rate, turnover time of split pond was estimated at 95 minutes. Table 3. Estimation of minimum required water flow rates based on DO consumption and TAN excretion rates Item Value Remark Target water quality requirements . - DO in inflow water (DOin, mg/L) 10 Based on water quality dynamics in commercial catfish split ponds (2 farms, 90 observations) measured for the past three years, DO and TAN requirements in inflow and outflow water has been established. TAN requirements were established considering safe levels for fathead minnows recommended by Russo and Thurston (1991) and theoretical no-observed-effect- concentration (NOEC, 9% of 96-h LC50, Ashe et al. 1996). - DO in outflow water (DOout, mg/L) 9 - TAN in inflow water (TANin, mg/L) 0.194 (0.065 as NH3 at pH 9 and 80 F) - TAN in outflow water (TANout, mg/L) 0.200 (0.048 as NH3 at pH9 and 80 F) Unit oxygen production and ammonia removal rates in split ponds - Unit oxygen production rate (UOP, g O2/kg feed•day-1) 32.35 The values are averages derived from the data collected in commercial catfish split ponds for the past three years (personal communication with Mathew Recsetar, Extension specialist at UAPB) - Unit ammonia removal rate (UAR, g TAN/kg feed•day-1) 33.93 Estimation of minimum required water flow rates (Q) - DO consumption basis (m3/min) 6.10 (1,614 gpm) Q = [(Daily feed amount x 0.36)-{(UOP x Daily feed amount)/1000}] / [1440 x {(DOin - DOout)/1,000,000}], (Losordo and Westers 1994) - TAN excretion basis (m3/min) 25.96 (6,869 gpm) Q = [{DAE - (UAR x Daily feed amount)/1000}] / [1440 x {(TANout - TANout)/1,000,000}], (Losordo and Westers 1994) The drag force equation was used to size a paddlewheel water circulator and a motor with respect to the rotational speed and wetted surface area of paddle, in order to pump the minimum required water flow rate estimated above. Generalized equations derived from the use of drag force equation for water flow rate, motor power, and driving shaft of paddlewheel circulator are as follows. Q (water flow rate, m3/min) = Σ [(0.5•Cd•ρw•cosθ•vb•Ab)/(1-k)]/1000 Equation 1 Ppw (motor power, HP) = Σ [0.0007•Cd•cosθ•vb3•Ab• (1-k)]/( Me•Ge) Equation 2 Equation 3 Engineering factors applied to approximate the minimum water flow rate and the motor capacity are presented in Table 4. Table 4. Engineering factors applied to size a paddlewheel water circulator Engineering factor considered Value or equation Drag Coefficient (Cd, unitless) 1.32 (Rouse 1946) Paddle angle (θ, degree) 45 Slip factor (k, fraction) 0.074+0.007•[ vb* / (3.14•wheel diameter)] *vb is tip velocity of paddle (m/sec), (Hendrick 2005) Density of Water (kg/m3) 998 Voltage (V) /wire phase 220 / 3 Motor energy transfer efficiency (Me, %) 85 Gear box energy transfer efficiency (Ge, %) 40 Using the mix and match approach between rotational speed and wetted area of paddle, we derived the sizes of paddlewheel and motor and presented the result in the Table 5. The maximum water depth of baitfish pond usually does not exceed 1.22 m (4 ft). Thus, allowable blade length that can be immersed was found to be 0.762 m (30 in), considering the existing paddlewheel circulators. As Park et al. (2014) recommended that the rotational speed of paddlewheel type circulators should not exceed 4-5 at a commercial catfish farm setting, we have set the standard rotational speed of paddle at 5 rpm. As a result, the width of blade was estimated to be 1.02 m (40 in) and water flow rate was expected to be 25.7 m3/min (6,807 gpm) accordingly. To pump the water flow rate, a 0.63 hp motor and a 4.32 cm (1.7 in) shaft were required. However, in order to ensure capability to pump enough water, we determined to use a variable frequency drive and install a motor (3 hp) and a shaft (6.19 cm or 2-7/16 in) that can run at a maximum rotational paddle speed of 7.5. Table 5. Results of sizing paddles, a driving motor, and a shaft Item Value Remark Target operational parameter - Maximum water depth (m) 1.22 (48 in) Considering support structures Adjustable rpm range : 0- 7.5 rpm - Allowable blade length (L, m) 0.762 (30 in) - Expected paddlewheel diameter (D, m) 2.59 (102 in) - Rotational speed (rpm) 5 Approximation of blade width and water flow rate - Paddle width (m) 1.02 (40 in) Mix and Match approach with combinations between the width and rotational speed of paddle using the drag force formula to achieve the minimum required water flow rate in Table 3. Equation 1. - Expected water flow rate at the given conditions (m3/min) 25.7 (6,807gpm) at 5 rpm 37.1 (9,813 gpm) at 7.5 rpm Approximation of driving motor size and shaft diameter - Required minimum horse power of driving motor (hp) 0.63 at 5 rpm 2.02 at 7.5 rpm Equation 2. Using a variable frequency drive, rotational speed will be adjusted up to a maximum rpm of 7.5in order to ensure enough water flow rate as needed. - Required minimum driving shaft diameter (Sdp, cm) 4.32 (1.7 in) at 5 rpm 5.59 (2.2 in) at 7.5 rpm Equation 3. To allow the motor and shaft to withstand force at the maximum rpm, we determined to install a 3 hp motor and a 6.19 cm (2-7/16 in) shaft. Based on this engineering design, we completed the construction of the earthen levee dividing fish basin (10%) and algae lagoon (90%). Currently we are fabricating a paddlewheel water circulator and will complete it by the end of February.
Publications
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