Aeration experiments were conducted in a brick masonry tank of dimension 4 m × 4 m × 1.5 m to study the design characteristics of pooled circular stepped cascade (PCSC) aeration system. Based on dimensional analysis, non-dimensional numbers related to geometric, dynamic and process parameters were proposed. The non-dimensional geometric parameters – number of steps (N), ratio of total height of cascade (H) to the bottom radius of cascade (Rb), % coverage of circumference of each step by enclosure (Pe) and number of enclosures in each step (Ne) were optimized. Maintaining the optimized geometric parameters (N = 6, H/Rb = 0.25, Pe = 20% and Ne = 9), aeration experiments were further conducted at different discharges (Q) to develop simulation equations for prediction of aeration characteristics of PCSC aeration system at different dynamic conditions. Simulation equations for oxygen transfer and power consumption based on Froude (Fr) criterion were developed subject to 0.0014 ≤ Fr ≤ 0.0144. SAE of the developed prototype PCSC aerators based on estimated brake power ranged between 2.43 and 3.23 kg O2/kWh. 相似文献
The selection of aerators and correct numbers can play an essential role in reducing the cost of production in aquaculture. The new generation aerators, namely spiral leaf, air‐jet, submersible and impeller, used in aquaculture, were assessed for its aeration efficiency and energy cost compared with the commonly used paddle wheel aerator. Of the aerators tested, the impeller had the highest aeration efficiency of 2.098 kg O2/kW hr, followed by paddle wheel with 1.436 kg O2/kW hr at 20‰ salinity. The spiral and air‐jet aerators had maximum aeration efficiency of 1.326 and 1.419 kg O2/kW hr, respectively, at 35‰ salinity. The submersible aerator was not efficient as its maximum efficiency was 0.380 kg O2/kW hr. The water flow by paddle wheel was 3 ft/sec and also provides better coverage than other types of aerators. The efficiency of aerators was high in optimum salinities (20‰ and 35‰) than the low or high saline condition. The average energy cost of shrimp pond aeration per hectare was lowest for impeller, followed by paddle wheel aerator. The study provided economic comparisons of vannamei culture using different aeration systems by keeping a uniform set of economic assumptions. Shrimp farms with impellors can give 14%–25% high returns across salinities, whereas spiral leaf can provide 5% high returns at 35‰ salinity. The combination of the type of aerators and the calculated use based on the salinity of the culture systems can result in energy‐saving and also a reduction in the production cost. 相似文献
Aerators are essential for maintaining the dissolved oxygen level in shrimp culture operations. Many types of aerators are promoted as suitable for shrimp culture, but their comparative efficiencies and water circulation patterns are least understood. The aerators viz, modified paddlewheel, Scorpion jet, Venture jet, Wavesurge were evaluated to compare the standard aeration efficiency at different saline conditions with the commonly used paddle wheel. The modified paddlewheel had the highest mean aeration efficiency of 2.018 kg O2/ kWh at 35‰, followed by the paddlewheel with 1.434 kg O2/ kWh at 20‰ water salinity. Compared to this, the Scorpion jet and the Wavesurge have shown the highest aeration efficiency of 0.667 and 0.412 kg O2/ kWh at 20 and 35‰ water salinities, respectively, whereas the Venture jet has given only. The aerator's performance was better at medium water salinities (20 and 35‰) than low (5‰) or high saline (50‰) conditions. In addition to aeration, the paddlewheel aerator has given the maximum water circulation speed 3 ft/sec and coverage distance of 24 m. The cost economics were derived by keeping all other expenses constant except aeration associated costs. The internal rate of returns in shrimp culture with a modified paddle wheel was 127 % compared to the commonly used paddle wheel (120 %). However, the scorpion and wavesurge aerators have shown returns of 47 % and 27 % respectively across the salinities. The selection and sizing of aerators based on the biomass and efficiency of the aeration systems can make considerable headway in decreasing the cost of production and energy use. 相似文献
Aeration experiments were conducted in brick masonry rectangular tanks of dimensions 2.9×2.9×1.6 and 5.9×2.9×1.6 m to study the effect of geometric and dynamic variables on aeration process based on dimension analysis. Non-dimensional numbers relating to standard aeration efficiency (SAE), effective power (P) and theoretical power per unit volume (P/V) termed as SAE′, Ne and X, respectively, are proposed. An optimal geometric similarity of various linear dimensions was established. It has been established that neither the Reynolds criterion nor the Froude criterion is singularly valid to simulate either SAE′ or Ne, simultaneously for different sizes of aerators, even though they are geometrically similar. Occurrence of scale effects due to the Reynolds and the Froude laws of similitude on both SAE′ and Ne are also evaluated. Simulation equations uniquely correlating SAE′, Ne and X were developed which can predict the aeration performance of paddle wheel aerators having the optimised geometric dimensions as established. 相似文献
A dynamic stock model was used for quantification of shrimp production and analysis of alternative management schemes of stocking density, pond size, starting time of aeration, and duration of cultivation for intensive commercial production of the shrimp Litopenaeus vannamei. Databases from Mexican farms were used to calibrate the model. Multiple linear regression models were employed to establish relationships between parameters of the stock model and the management variables. Water quality variables (dissolved oxygen, temperature, and salinity) were complementarily analyzed. The final weight of shrimp was directly related to duration of cultivation and dissolved oxygen, and inversely related to stocking density, pond size, and salinity. There were inverse relationships between the growth coefficient and temperature and dissolved oxygen and between mortality rate and temperature. Dissolved oxygen was significantly related to starting time of aeration. Simple linear regression and an equivalence test indicated that biomass at harvest (after 13 weeks in winter, and 20 weeks in summer) was adequately predicted by using the stock model and the multiple regression models. The highest production (winter, 6900 kg ha−1; summer, 12,600 kg ha−1) were predicted using 60 postlarvae m−2, small ponds (2 ha), and starting aeration at the first week of cultivation; while the lowest yields (winter, 2600 kg ha−1; summer, 6000 kg ha−1) were obtained using 40 postlarvae m−2, large ponds (8 ha), and delaying the start of aeration until the fifth week of cultivation. The lowest production was 38% (winter) and 48% (summer) of the highest yield. Using small ponds could be particularly important during winter cycles to increase production, while stocking density and starting time of aeration contributed less. In contrast, pond size played a minor role during summer cycles and stocking density was the most sensitive variable. 相似文献
A water streamer was designed for the purpose of enhancing cost-efficient circulation between the water surface and bottom of shrimp aquaculture ponds. We took direct measurements of the water current field induced by the designed aerator in a large rectangular reservoir of dimensions (L)50 × (W)19 × (D)1.3 m3 and compared the results with those of a standard Taiwanese paddle-wheel aerator. Vertical circulation between the surface and the bottom induced by the paddle wheel aerator was less than that by the designed aerator. Furthermore, the paddle-wheel aerator consumed more electric power than the designed aerator. The structures of water current induced by the two aerators are elucidated, and the advantages and disadvantages of the aerators are discussed.Auxiliary employment of the designed aerators may contribute to delivery of high DO water throughout the pond, which is more efficient than a paddle wheel aerator. 相似文献
The effects of aeration and alkalinity on water quality and product quality of Nile tilapia (Oreochrmis niloticus) were determined for simulated commercial hauling conditions. Three types of aeration were tested: pure oxygen aeration with a fine bubble diffuser (Oxygen), air aeration with medium bubble diffusers (Air), and a combination of both pure oxygen aeration with a fine bubble diffuser and air aeration with a medium bubble diffuser (Mixed). Simulated transport hauls were conducted at two initial alkalinities: 1.74 ± 0.11 meq/L (Low) and 8.84 ± 0.55 meq/L (High).The Air treatments resulted in the lowest carbon dioxide concentration, and the highest pH and un-ionized ammonia concentrations. At high alkalinities, the Air treatments were unable to maintain adequate dissolved oxygen levels. The Mixed treatment resulted in reduced carbon dioxide and dissolved oxygen concentrations. The Oxygen treatment resulted the highest dissolved oxygen, highest carbon dioxide, and lowest pH and un-ionized ammonia. Un-ionized ammonia concentrations were higher with the High Alkalinity treatments because of higher pH. Significant mortality was observed in the Air treatments in both the Low- and High-Alkalinity treatments. Mortality in the Oxygen and Mixed treatments for both low and high alkalinities were comparable to that observed in commercial tilapia transport using fine bubble diffusers and pure oxygen.These results indicate that mortality due directly to hauling water quality will not be increased at high alkalinity, if pure oxygen aeration is used. The potential effects of water quality during hauling on survival and product quality may be less than the impact from (a) physical damage from loading and un-loading and (b) physiological problems resulting from pH and temperature shock during the transfer from the hauling tanks to retail holding systems, especially for fish of reduced fitness. 相似文献
A case study is presented to compare the results of design and management including circulation and dissolved oxygen management at a modified split-pond facility in west-central Alabama to the recommended design. Modifications included: the use of and a propeller pump instead of a slow-moving paddlewheel, lack of baffle in the waste cells, waste cell to fish cell ratio size, and improperly positioned aerators and DO sensing probes.Over a three year time period, the modified split-pond facility had net yields of hybrid catfish (Ictalurus punctatus ♀ x I. furcatus ♂) that reached up to 11,416 kg/ha/year; however, this includes several reports of fish kills. The present study experienced a minimum 15% reduction in net production compared to the recommended design values with a maximum potential loss of 54%. Ponds used an axial pump to transfer water between a 6:1 ratio of waste treatment area to fish grow-out area. Water flowed from the fish cell to the waste cell at a rate of 31.2 m3/min and from the waste cell back to the fish cell at a rate of 0.78 m3/min. Aerators used 5619–7492 kW-hr/ha which is more than the electrical use in traditional ponds (2238 kW-hr/ha). Even with the extra aeration, this study had at least one fish cell and one waste cell drop below a dissolved oxygen concentration of 2.5 mg/L. These specific modifications may lead to poor survival and production in split-pond aquaculture and are discussed with best management practices of the recommended design. 相似文献
ABSTRACT Vertical water circulation by the paddle wheel aerator was determined by measuring dissolved oxygen profiles in a 3.6-m deep watershed pond during daylight hours, using aerated and non-aerated treatments. The paddle wheel aerator circulated the well-oxygenated surface water to the pond bottom, producing a uniform dissolved oxygen profile in the aerated treatment, while the non-aerated treatment maintained high dissolved oxygen concentrations near the surface with low dissolved oxygen concentrations near the pond bottom. The aerated treatment contained 35.6% less dissolved oxygen than the non-aerated treatment after four hours as a result of operating the aerator during the daytime. The paddle wheel aerator, with a shallow (10 cm) paddle immersion, is effective in vertically circulating water in deeper ponds. However, substantial loss of dissolved oxygen may result from operating the aerator on days with high rates of photosynthesis. 相似文献
The feeding inefficiencies associated with intensively cultured prawn systems have a significant financial cost and environmental impact. Initial trials of a commercial system using sound to manage feeding within cultured systems have achieved promising results with an impressive food conversion (food weight/biomass) ratio of 1.42. Whilst these results demonstrate the potential benefit of employing passive acoustics for feed management, the underlying technologies are not well understood by industry or the research community. Consequently, a sound based study of feeding tiger prawns is conducted to investigate the key challenges associated with passive acoustic approaches; sound detection and feed demand estimation. The study finds that tiger prawns produce impulsive sound signatures during feeding that can be used as a proxy of feeding activity. Spectral features of the feeding signatures can be used to detect feeding activity within acoustically complex farm ponds (feeding signal to noise ratios less than −40 dB), given they are largely disjoint from the background noise spectrum (aerators) across all farm recordings. One of the potential challenges identified with sound based feed detection is that other sources of event driven interference arise (i.e. rain and faulty aerators), which can be misclassified as feeding. Whilst our investigation indicates that sound based detection of feed events are plausible, it is unclear how accurate it is to estimate the quantity of consumed pellets from feeding sound. Our study provides evidence to support its feasibility, given the temporal evolution of feeding sounds and pellet consumption were linearly related across tank and pond based feeds, respectively (R2 = 0.95 and R2 = 0.96). 相似文献
Performance of sediment microbial fuel cell (SMFC) with external resistance (SMFC-1) as well as short-circuited mode (SMFC-2) was evaluated at different operating temperatures (28–30 °C and 21–25 °C) and in presence and absence of aeration at the cathode. The performance was evaluated in terms of chemical oxygen demand (COD) removal and total kjeldahl nitrogen (TKN) removal for offering in situ treatment of aquaculture pond water. SMFC-2 demonstrated maximum COD and TKN removal efficiencies both in the absence and presence of aeration near cathode as compared to SMFC-1. With aeration at cathode, the COD and TKN removal efficiencies were 79.4% and 92.6% in SMFC-1 and 84.4% and 95.3% in SMFC-2, respectively. Without aeration and at lower operating temperature, the COD and TKN removals were slightly lower, yet satisfying aquaculture quality norms. SMFCs demonstrated effective in situ remediation of aquaculture water and can drastically save the operating cost of aquaculture. 相似文献
Engineering considerations for paddlewheel aeration in vegetated shallow water ponds for the production of procambarid crawfish is necessary to ensure cost-effective application. Three experimental ponds (approximately 2 ha each) were planted with rice in August as forage for the resident pond population of red swamp crawfish, Procambarus clarkii, and flooded in October. Two 2.2 kW (3 hp), single-phase electric motor (110 Vac) paddlewheel aerators were placed in each pond. The aerator rotors were 160-cm long and 95-cm in diameter. The aerator rotor had 36 paddles with half the paddles 27.3-cm long and half 34.9-cm long. Rotor speed was set at 83 rpm and operated at three paddle submergence settings: 7.6, 12.7, and 17.8 cm below the water surface. Over a 20-week period between November and April, channel velocity, head difference, and aerator amperage was measured for both one and two aerators in operation in each pond. Results indicated that circulation of oxygenated water from the aerators can be accomplished as efficiently with a single aerator set at a lower paddle depth (7.6-cm) compared to operating two aerators set at a greater paddle depth (12.7 or 17.8-cm). However, based on the apparent efficiency of the aerators and the calculated channel roughness coefficients values obtained from the channel velocities, paddlewheel aerators are an inefficient option for circulating the pond water especially when rice foliage dominants the total vegetative biomass of the pond. 相似文献
A survey was conducted to determine the geometry, operating parameters, and other key features of large circular or octagonal culture tanks used to produce Atlantic salmon smolt and post-smolt at six major Norwegian Atlantic salmon production companies. A total of 55 large tanks were reported at seven land-based hatchery locations, i.e., averaging 7.9 (range of 4–12) large tanks per land-based site. In addition, one 21,000 m3 floating fiberglass tank in sea was reported. Culture volume ranged from 500 to 1300 m3 for each land-based tank. Most tanks were circular, but one site used octagonal tanks. Land-based tank diameters ranged from 14.5 to 20 m diameter, whereas the floating tank was 40 m diameter. Maximum tank depths ranged from 3.5 to 4.5 m at land-based facilities, which produced diameter-to-average-depth ratios of 3.6:1 to 5.5:1 m:m. The floating tank was much deeper at 20 m, with a diameter-to-average-depth ratio of only 2.4:1 m:m. All land-based tanks had floors sloping at 4.0–6.5% toward the tank center and various pipe configurations that penetrated the culture tank water volume at tank center. These pipes and sloping floors were used to reduce labor when removing dead fish and harvesting fish.Maximum flow ranged from 3 to 19 m3/min per land-based tank, with 400 m3/min at the floating tank, but tank flow was adjustable at most facilities. Land-based tanks were flushed at a mean hydraulic retention time (HRT) of 35–170 min. Maximum feed load on each land-based tank ranged from 525 to 850 kg/day, but the floating tank reached 3700 kg/day. Almost half of the large tanks reported in this survey were installed or renovated since 2013, including the three tank systems with the highest flow rate per tank (greater than 17.6 m3/min). These more recent tanks were operated at more rapid tank HRT’s, i.e., from 34.8 to 52.5 min, than the 67–170 min HRT typical of the large tanks built before 2013. In addition, flow per unit of feed load in land-based tanks that began operating before 2010 were lower (19–30 m3 flow/kg feed) than in tanks that began operating later (33–40 m3 flow/kg feed). In comparison, the floating tank operates at a maximum daily tank flow to feed load of 160 m3 flow/kg feed, which is the least intensive of all tanks surveyed. Survey results suggest that the recently built tanks have been designed to operate at a reduced metabolic loading per unit of flow, a tendency that would improve water quality throughout the culture tank, all else equal. This trend is possible due to the ever increasing application of water recirculating systems. 相似文献
Convenient, economical, and reduced labor fish harvest and transfer systems are required to realize operating cost savings that can be achieved with the use of much larger and deeper circular culture tanks. To achieve these goals, we developed a new technology for transferring fish based on their avoidance behavior to elevated concentrations of dissolved carbon dioxide (CO2). We observed this behavioral response during controlled, replicated experiments that showed dissolved CO2 concentrations of 60–120 mg/L induced rainbow trout (Oncorhynchus mykiss) to swim out of their 11 m3 “growout” tank, through a transfer pipe carrying a flow with ≤23 mg/L dissolved CO2, into a second 11 m3 “harvest” tank. The research was conducted using separate groups of rainbow trout held at commercially relevant densities (40–60 kg/m3). The average weight of fish ranged from 0.15 to 1.3 kg during the various trials. In all trials that used a constant flow of low CO2 water (≤23 mg/L) entering the growout tank from the harvest tank, approximately 80–90% of the fish swam from the growout tank, through the transfer pipe, and into the harvest tank after the CO2 concentration in the growout tank had exceeded 60 mg/L. The fish that remained in the growout tank stayed within the area of relatively low CO2 water at the entrance of the transfer pipe. However, the rate of fish transfer from the growout tank to the harvest tank was more than doubled when the diameter of the transfer pipe was increased from 203 to 406 mm. To consistently achieve fish transfer efficiencies of 99%, water flow rate through the fish transfer pipe had to be reduced to 10–20% of the original flow just before the conclusion of each trial. Reducing the flow of relatively low CO2 water near the end of each fish transfer event, restricted the zone of relatively low CO2 water about the entrance of the fish transfer pipe, and provided the stimulus for all but a few remaining fish to swim out of the growout tank. Results indicate that the CO2 avoidance technique can provide a convenient, efficient, more economical, and reduced labor approach for fish transfer, especially in applications using large and well mixed circular culture tanks. 相似文献
Most commercial catfish farms use multiple-batch production systems that contain fish sizes ranging from recently stocked fingerlings to fish weighing more than 1.5 kg. Currently, there are no accurate and cost-effective techniques to estimate pond inventories of catfish. Three trials were conducted in earthen catfish ponds with a 12 m × 8 m trawl (bar mesh at mouth of 3.8-cm; 2.54-cm at cod end). The first two trials included trawling with and without feed as bait in 4-ha commercial catfish ponds (Trial 1) and in 1.6-ha experimental ponds (Trial 2). In Trial 3, the trawl was pulled three times without feeding in 1.6-ha experimental ponds. Mean individual weights and size distributions of catfish caught by the trawl were statistically similar to those of catfish caught by the seine (Trial 1) and to stocking data (Trial 2). Single pulls with the trawl resulted in 73% error in estimated fish inventories in Trial 3. However, if pulled two times, the estimated catfish inventory error dropped to 7%, more accurate than other inventory methods, but was variable (coefficient of variation = 186%). The trawl appears to have potential as a means to sample commercial catfish ponds to estimate means and frequency distributions of fish size, but additional refinement and correction would be needed for it to be used reliably to estimate total pond inventory. 相似文献
Sea bass (Dicentrarchus labrax) (135 ± 4 g) were reared under tank-based recirculating aquaculture system for a 63-day period at four densities: 10, 40, 70, 100 kg m?3. Fish performance, stress indicators (plasma cortisol, proteonemia plus other blood parameters—Na+, K+, glucose, pH, total CO2?) and water quality were monitored. At the end of the 63-day period, resistance to infection was also studied by a nodavirus challenge. A 25-day test was performed on fish from two extreme densities (10 and 100 kg m3) and one intermediate density (40 kg m3).With regards to the different density treatments, there was no significant difference between the daily feed intake (DFI) and the specific growth rate (SGR) up to a density of 70 kg m?3. No significant difference was found between treatments concerning the feed conversion ratio (FCR) and the mortality rate. No density effect was observed on the fish stress level (plasma cortisol) or on sensitivity to the nodavirus challenge. Under these experimental rearing conditions, the density above 70 kg m?3 has an impact on growth performance (DFI and SGR) indicators and also some blood parameters (CO2) at the highest density tested (100 kg m?3).This study suggests that a density up to 70 kg m?3 has no influence on sea bass performance and welfare. At 100 kg m?3, average specific growth rate was decreased by 14% without welfare deterioration according to the welfare indicators monitored. 相似文献
Split-pond aquaculture systems are being implemented by United States (US) catfish farmers as a way to improve production performance. The split-pond consists of a fish-culture basin that is connected to a waste-treatment lagoon by two water conveyance structures. Water is circulated between the two basins with high-volume pumps (water circulators) and many different units are being used on commercial farms. In this study circulator performance was evaluated with four different circulating systems. Rotational speeds ranged from 0.5 to 3.5 rpm for a twin, slow rotating paddlewheel; 12.5 to 56.5 rpm for a paddlewheel aerator; 60 to 240 rpm for a high-speed screw pump; and 150 to 600 rpm for an axial-flow pump. Water flow rates ranged from 8.6 to 77.6 m3/min and increased with increasing rotational speed. Power input varied directly with flow rate and ranged from 0.24 to 13.43 kW for all four circulators. Water discharge per unit power input (i.e., efficiency) ranged from 3.5 to 70.9 m3 min−1 kW−1 for the circulators tested. In general, efficiency decreased as water flow rate increased. Initial investment cost for each circulator and complete circulating system ranged from US $5850 to $22,900, and $15,335 to $78,660, respectively. The least expensive circulator to operate was the twin, slow-rotating paddlewheel, followed by the paddlewheel aerator, high-speed screw pump, and axial-flow pump. Our results show that four different circulating systems can be effectively installed and used to circulate water in split-ponds. However, water flow rate, rotational speed, required power input, efficiency, initial investment cost, and operational expense varied greatly among the systems tested. Long term studies are underway to better define the relationship between water flow rate and fish production in split-ponds. That information will help identify the water circulating system most appropriate for split-pond aquaculture. 相似文献
An on-station trial was conducted to evaluate the effect of stocking density of freshwater prawn and addition of different levels of tilapia on production in carbon/nitrogen (C/N) controlled periphyton based system. The experiment had a 2 × 3 factorial design, in which two levels of prawn stocking density (2 and 3 juveniles m? 2) were investigated in 40 m2 earthen ponds with three levels of tilapia density (0, 0.5 and 1 juveniles m? 2). A locally formulated and prepared feed containing 30% crude protein with C/N ratio close to 10 was applied considering the body weight of prawn only. Additionally, tapioca starch was applied to the water column in all ponds to increase C/N ratio from 10 (as in feed) to 20. Increasing stocking density of tilapia decreased the chlorophyll a concentration in water and total nitrogen in sediment, and increased the bottom dissolved oxygen. The concentrations of inorganic nitrogenous species (NH3–N, NO2–N and NO3–N) were low due to maintaining a high C/N ratio (20) in all treatment ponds. Increasing prawn density decreased periphyton biomass (dry matter, ash free dry matter, chlorophyll a) by 3–6% whereas tilapia produced a much stronger effect. Increasing stocking density of freshwater prawn increased the total heterotrophic bacterial (THB) load of water and sediment whereas tilapia addition decreased the THB load of periphyton. Both increasing densities of prawn and tilapia increased the value of FCR. Increasing prawn density increased gross and net prawn production (independent of tilapia density). Adding 0.5 tilapia m? 2 on average reduced prawn production by 12–13%, and tilapia addition at 1 individual m? 2 produced a further 5% reduction (independent of prawn density). The net yield of tilapia was similar between 0.5 and 1 tilapia m? 2 treatments and increased by 8.5% with increasing stocking density of prawn. The combined net yield increased significantly with increasing stocking density of prawn and tilapia addition. The significantly highest benefit cost ratio (BCR) was observed in 0.5 tilapia m? 2 treatment but freshwater prawn density had no effect on it. Therefore, both stocking densities (2 and 3 juveniles m? 2) of prawn with the addition of 0.5 tilapia m? 2 resulted in higher fish production, good environmental condition and economic return and hence, polyculture of prawn and tilapia in C/N controlled periphyton based system is a promising options for ecological and sustainable aquaculture. 相似文献
Most developed aquacultural models are designed for foreign species and environments and hence the need to develop a model for African farmed fish. This paper describes the development of an Aquacultural System Management Tool (AQUASMAT) for predicting tank systems for culturing African catfish (Clarias gariepinus). The model development involved formulation of theoretical relationships for intensive tank-based fish culture from existing models and development of program code with Microsoft® Visual C# (C-sharp). The model was designed to predict the effect of different management operations on fish yield, identify and quantify the cause, effect and relationships between water quality parameters, and suggest remedial actions for impaired systems. It also predicts economic viability of the production system based on cost input used in the system and track the fate of many water quality parameters which are not readily measured. The developed model was calibrated, validated and applied to ascertain its suitability. The model calibration results showed a close trend between the predicted and observed data, indicating a reasonable performance and adequacy of system representation. Regression analysis on the validated results indicated a strong correlation between predicted and observed data for TAN, temperature, NO3 and fish weight. Model adequacy results were within the recommended range, with relative bias (rB) of 0.014, −0.159, 0.039, −0.104 and F-test of 0.740, 0.877, 0.887 and 0.736 for temperature, DO, TAN and fish weight, respectively. Model sensitivity analysis showed that the model was very sensitive to parameters such as temperature, pond size, feed and stocking density, hence accurate estimation of these parameters is recommended for optimal performance of the model. Model experimentation results showed DO and TAN were within tolerable water quality limits only for stocking densities of 7 fish/m2, 14 fish/m2 and 21 fish/m2 and predicted profit in Nigerian currency, Naira () of 1100:00, 1681:00, 1575:00, 820:00 for 7 fish/m2, 14 fish/m2, 21 fish/m2 and 28 fish/m2, respectively, and a loss of 1501:00 for 35 fish/m2 for the model scenarios. 相似文献
