Economic Interactions Between Feeding Rates and Stocking Densities in Intensive Catfish Ictalurus punctatus Production

Feed represents the largest cost input in intensive catfish Ictalurus punctatus production. Daily feed rations are generally related to stocking densities, up to a point at which high feeding rates begin to affect water quality. There has been no prior research to analyze the economic interactions between feeding and stocking rates. Econometric techniques were used to estimate a Just-Pope catfish production function, which was used to compute marginal products of inputs, and to identify stocking and feeding rates associated with the boundaries between Stages I, II, and III of the production function. Survey data collected by USDA National Animal Health Monitoring System were used for this analysis. Maximum yield, when accounting for both stocking and feeding rates, occurred at about 30,000 fingerlings/ha. However, profit-maximizing stocking densities ranged between 16,942 and 21,312 fingerlings/ha, depending upon expected catfish and feed prices. Farmers stocking at higher rates could be attempting to maximize yield instead of profit.     

Comparative Economics of US Catfish Production Strategies: Evidence from a Cross‐sectional Survey

Understanding the effects of specific management strategies on yields and economic outcomes on commercial catfish farms could provide useful guidance to catfish farmers on the most profitable sets of production practices. Data from the U.S. Department of Agriculture–National Animal Health Monitoring System (USDA–NAHMS) 2009 survey of production practices on catfish farms in Alabama, Arkansas, Louisiana, and Mississippi were used to identify five clusters of catfish farms that use various stocking densities, channel versus hybrid catfish, different aeration levels, and utilize automated oxygen sensors. The lowest production costs ($1.96/kg) were found in cluster 1 and were followed in order of increasing costs per kilogram of clusters 2 and 4 ($2.16/kg) and cluster 5 ($2.73/kg); the highest cost corresponded to cluster 3 ($2.84/kg). The lowest risk levels corresponded to the clusters with the lowest production costs per kilogram of fish and the highest risk levels to the highest production costs. This analysis demonstrated that different types of management models can achieve similar levels of production costs ($/kg), and it appears that there is not one single economically optimum way to raise catfish. The key to least‐cost production is to balance the use of inputs, their associated costs, and the yield produced to achieve economic efficiency within the farm's overall business and management model.     

Economics of Intensively Aerated Catfish Ponds

The US catfish industry is evolving by adopting production‐intensifying practices that enhance productivity. Catfish producers have increased aeration rates over time, and some now use intensive rates of aeration (>9.33 kW/ha). Costs and production performance were monitored at commercial catfish farms using high levels of aeration (11.2–18.7 kW/ha) in Alabama, Arkansas, and Mississippi. A multivariate‐cluster analysis was used to identify four different management clusters of intensively aerated commercial catfish farms based on stocking density, size of fingerlings at stocking, and feed conversion ratios (FCR). Breakeven prices of hybrid catfish raised in intensively aerated pond systems were estimated to range from $1.86/kg to $2.17/kg, with the lowest costs associated with the second greatest level of production intensity. The two medium‐intensity clusters generated sufficiently high revenues for long‐term profitability. However, the least‐intensive and the most‐intensive clusters were economically feasible only when catfish and feed prices were closer to less probable market prices. Feed price, FCR, and yield contributed the most to downside risk. Intensive aeration in catfish ponds, up to the levels analyzed in this study, appears to be economically feasible under the medium‐intensity management strategies identified in this analysis.     

Influence of a Bacterial Amendment on Water Quality in Small Research Ponds for Channel Catfish,Ictalurus punctatus,Production

There has been considerable interest worldwide in applying bacterial inocula to channel catfish ponds for improving water quality, especially for acceleration of ammonia nitrogen oxidation through bacterial nitrification. The effects of a selected bacterial amendment on water quality in small research ponds for channel catfish production were evaluated at the E. W. Shell Fisheries Center, Auburn University, Auburn, Alabama. Three ponds were treated with the bacterial amendment Waste & Sludge Reducer? (Keeton Industries, Wellington, CO, USA) at three times the dose recommended by the manufacturer every 2 wk, and three ponds served as controls. There were nonconsistent minor differences in water quality between ponds treated with a commercial bacterial amendment and control ponds on several sampling dates. However, the average concentrations of water quality variables did not differ (P > 0.05) between the treatments and control. Channel catfish yield was not improved by applying the bacterial amendment. This study demonstrates that the bacterial amendment was of no benefit in improving water quality in well‐managed catfish ponds where stocking rates, feeding rates, and amount of aeration are balanced.     

Nutrient flows in an integrated pig, maggot and fish production system

Direct use of pig wastes as inputs into fish culture systems may be unacceptable or an inferior use of valuable inputs. High value, but non-filter feeding fish, such as African catfish, Clarias gariepinus (Burchell), may be unable to recover nutrients efficiently through the pond food web and require complete diets in intensive culture. Live feeds such as the larval stage of the green blow fly. Lucilia sericata, can be used as intermediate organisms to utilize pig waste and subsequently be fed live as part of a complete ration for catfish raised in cages. The nutrient efficiency of the system is further enhanced by the stocking of phytophagous fish, the Nile tilapia, Oreochromis niloticus (L.), in the pond in which the catfish culture cages are suspended. A model derived from on-farm experimentation is presented that demonstrates system design and nutrient efficiencies. An extrapolated catfish production of 61 year¹ using only fly larvae produced from a standing herd of approximately 1000 fattening pigs was demonstrated. The static water pond in which the catfish were cultured ensured that the environmental impact of both pig and catfish systems was minimal compared to conventional production systems.     

Evaluation of the Economics of Multi-Batch Channel Catfish Ictalurus punctatus Production Fed an Industry Standard and Three Alternative Diets

The purpose of this study was to determine the feasibility of growing marketable channel catfish, Ictalurus punctatus, from pond-run fingerlings (15.9 g/fish) using low stocking densities (7,413 or 14,826 fish/ha) and electrified bug lights to enhance natural forage available to fish. Even at low stocking densities, fish only averaged 0.2 kg at the end of the growing season. Because marketable sizes of fish were not reached over the growing season, stocking small fingerlings at these rates would not be practical under most commercial production scenarios. Nutritionally, captured insects from electrified bug lights were near a complete diet for catfish, but bug lights did not capture sufficient quantities of insects to affect fish production in either stocking density. Stocking small fingerlings at low stocking rates does not produce market‐sized catfish during one growing season; commercially available bug lights did not provide adequate amounts of natural forage to affect production variables.     

Production Characteristics, Water Quality, and Costs of Producing Channel Catfish Ictalurus punctatus at Different Stocking Densities in Single-batch Production

Channel catfish Ictalurus punctatus farming is the largest component of aquaculture in the USA. Culture technologies have evolved over time, and little recent work has been conducted on the effects of stocking density on production characteristics and water quality. Twelve 0.1‐ha ponds were stocked with 13‐ to 15‐cm fingerlings (16 g) at either 8600, 17,300, 26,000, or 34,600 fish/ha in single‐batch culture with three replicates per treatment. Fish were fed daily to apparent satiation with a 32% floating commercial catfish feed. Nitrite‐N, nitrate‐N, total ammonia nitrogen (TAN), total nitrogen, total phosphorus, chemical oxygen demand (COD), Secchi disk visibility, chlorophyll a, chloride, total alkalinity, total hardness, pH, temperature, and dissolved oxygen (DO) were monitored. Ponds were harvested after a 201‐d culture period (March 26, 2003 to October 13, 2003). Net yield increased significantly (P < 0.05) as stocking density increased, reaching an average of 9026 kg/ha at the highest density. Growth and marketable yield (>0.57 kg) decreased with increasing stocking density. Survival was not significantly different among densities. Mean and maximum daily feeding rates increased with density, but feed conversion ratios did not differ significantly among treatments (overall average of 1.42), despite the fact that at the higher stocking densities, the feeding rates sometimes exceeded 112 kg/ha per d (100 lb/ac per d). Morning DO concentrations fell below 3 mg/L only once in a 34,600 fish/ha pond. Concentrations of chlorophyll a, COD, nitrite‐N, and TAN increased nominally with increasing feed quantities but did not reach levels considered problematic even at the highest stocking densities. Breakeven prices were lowest for the highest stocking density even after accounting for the additional time and growth required for submarketable fish to reach market size. While total costs were higher for the higher density treatments, the relatively higher yields more than compensated for higher costs.     

The economics of sutchi catfish (Pangasianodon hypophthalmus) aquaculture under three different farming systems in rural Bangladesh

This paper examines production costs and returns of sutchi catfish (Pangasianodon hypophthalmus) aquaculture under three different farming systems in Bangladesh. Based on the production technology, sutchi catfish farming is classified as extensive, semi‐intensive and intensive. Results showed that sutchi catfish farming is profitable irrespective of the level of intensification and in all three instances the cost of feed dominated the variable costs of production. The average annual production costs were estimated at US$5217 ha^?1 in intensive farming, while US$2694 ha^?1 in semi‐intensive and US$981 ha^?1 in extensive farming. Despite the higher production costs per hectare, the average annual net return was higher in intensive farming (US$3364), compared with semi‐intensive (US$2048) and extensive (US$1099) farming. The average annual production per hectare under intensive farming conditions (13 945 kg) was higher than semi‐intensive (7705 kg) and extensive (3380 kg) farming mainly due to higher levels of inputs, including seed, feed, fertilizer and labour. However, the Cobb–Douglas production function model suggests that inputs are inefficiently used in the intensive farming system. Conversely, there is enough scope to increase the production and income from the semi‐intensive and extensive farming systems by using more inputs.     

Profit-Maximizing Stocking Rates for Channel Catfish in Cages

A production function for catfish in cages was estmated by combining data from a survey of producers in Alabama with data from experimental studies in Texas, South Carolina, and Alabama. Explanatory variables in the quadratic model included cage stocking density, fingerling size, length of growing season, feed conversion rate, squared and cross-product terms, and dummy variables for data sources. Model R ² was 87%. Profit-maximizing stocking densities were calculated for varying levels of growing season duration, fingerling size, fingerling price and market price. Optimal stocking density was shown to be most sensitive to length of growing season.     

Effects of Feeding Diets with and without Fish Meal on Production of Channel Catfish,Ictalurus punctatus,Stocked at Varying Densities

ABSTRACT

Animal protein, generally fish meal, has traditionally been used in the diet of channel catfish. However, our previous research indicates that animal protein is not needed for growing stocker-size catfish to food fish when the fish are stocked at densities typical of those used in commercial catfish culture. Whether this holds when fish are stocked at high densities is not known; thus, we conducted an experiment to evaluate the effect of feeding diets with and without fish meal to channel catfish stocked in earthen ponds at different densities. Two 32% protein-practical diets containing 0% or 6% menhaden fish meal were compared for pond-raised channel catfish, Ictalurus punctatus, stocked at densities of 14,820, 29,640, or 44,460 fish/ha. Fingerling channel catfish with average initial weight of 48 g/fish were stocked into 30 0.04-ha ponds. Five ponds were randomly allotted for each fish meal level?×?stocking density combination. Fish were fed once daily to satiation for two growing seasons. There was a significant interaction between stocking density and fish meal for net production; net production increased in fish fed a diet containing fish meal compared with those fed an all-plant diet at the highest stocking density, but not at the two lower stocking densities. Net production of fish fed diets with and without fish meal increased as stocking density increased. Viewing the main effect means, weight gain decreased and feed conversion ratio increased for fish stocked at the two highest densities, and survival was significantly lower at the highest stocking density. Visceral fat decreased in fish at the two highest stocking densities. Body composition data were largely unaffected by experimental treatment except for a reduction in percentage filet fat in fish at the highest stocking density, and fish that were fed diets containing fish meal had a lower percentage fillet protein and a higher percentage fillet fat. It appears that at stocking densities two to three times higher than generally used, animal protein (fish meal) may be beneficial in the diet of channel catfish. In regard to stocking densities, high stocking results in higher overall production, but the average fish size decreased as stocking density increased.     

Effect of Dietary Protein Concentration and Stocking Density on Production Characteristics of Pond-Raised Channel Catfish Ictalurus punctatus

Diets containing 28% and 32% crude protein were compared for pond‐raised channel catfish Ictalurus punctatus stocked at densities of 14,820, 29,640, or 44,460 fish/ha. Fingerling channel catfish with average initial weight of 48.5 g/fish were stocked into 30 0.04‐ha ponds. Five ponds were randomly allotted for each dietary protein ± stocking density combination. Fish were fed once daily to satiation for two growing seasons. There were no interactions between dietary protein concentration and stocking density for any variables. Dietary protein concentrations (28% or 32%) did not affect net production, feed consumption and weight gain per fish, feed conversion ratio, survival, processing yields, fillet moisture, protein and ash concentrations, or pond water ammonia and nitrite concentrations. Fish fed the 32% protein diet had slightly but significantly lower levels of visceral and fillet fat than fish fed the 28% protein diet. As stocking density increased, net production increased, while weight gain of individual fish, feed efficiency, and survival decreased. Stocking densities did not affect processing yield and fillet composition of the fish. Although highly variable among different ponds and weekly measurements, ponds stocked at the highest density exhibited higher average levels of total ammonia‐nitrogen (TAN) and nitrite‐nitrogen (NO₂‐N) than ponds stocked at lower densities. However, stocking density had no significant effect on un‐ionized ammonia‐nitrogen (NH₃‐N) concentrations, calculated based on water temperature, pH, and TAN. By comparing to the reported critical concentration, a threshold below which is considered not harmful to the fish, these potentially toxic nitrogenous compounds in the pond water were generally in the range acceptable for channel catfish. It appears that a 28% protein diet can provide equivalent net production, feed efficiency, and processing yields as a 32% protein diet for channel catfish raised in ponds from advanced fingerlings to marketable size at densities varying from 14,820 to 44,460 fish/ha under single‐batch cropping systems. Optimum dietary protein concentration for pond‐raised channel catfish does not appear to be affected by stocking density.     

Effect of Multiple-batch Channel Catfish, Ictalurus punctatus, Stocking Density and Feeding Rate on Water Quality, Production Characteristics, and Costs

To quantitatively define relationships among stocking densities, feeding rates, water quality, and production costs for channel catfish, Ictalurus punctatus, grown in multiple‐batch systems, twelve 0.1‐ha earthen ponds were stocked at 8,600, 17,300, 26,000, or 34,600 fingerlings/ha along with 2,268 kg/ha of carryover fish. Fish in all ponds were fed daily to apparent satiation using 32% protein floating feed. Temperature and dissolved oxygen in each pond were monitored twice daily; pH weekly; nitrite‐N, total ammonia nitrogen, and Secchi disk visibility every 2 wk; nitrate‐N, chlorophyll a, total nitrogen, total phosphorus, and chemical oxygen demand monthly; and chloride every other month. The costs of producing channel catfish at different stocking densities were estimated. There were no significant differences (P > 0.05) as a result of stocking density among treatment means of (1) gross or net yields, (2) mean weights at harvest, and (3) growth or survival of fingerlings (24–36%) and carryover fish (77–94%). Mean and maximum daily feeding rates ranged from 40 to 53 kg/ha/d and 123 to 188 kg/ha/d, respectively, and feed conversion ratios averaged 1.75. There were no differences in any feed‐related parameter as a result of density. Water quality variables showed few differences among densities at samplings and no differences when averaged across the production season. Yield of fingerlings increased as stocking density increased with significant differences between the two highest and the two lowest stocking densities. Breakeven prices were lower at the higher stocking densities as a result of the higher yield of understocked fish and similar mean individual fish weights produced at these higher stocking densities. Overall, varying stocking densities of fingerlings in multiple‐batch systems had little effect on production efficiency and water quality. Additional research on managing the population structure of carryover fish in commercial catfish ponds may be warranted.     

Production risk,technical efficiency,and input use nexus: Lessons from Bangladesh aquaculture

The optimal use of resources in aquaculture is important, especially in developing countries, to obtain the highest possible outcome from the production process to support food security and poverty alleviation. Thus, within this study, the risk, efficiency, and input‐use variation in aquaculture farms in Bangladesh is investigated using a flexible stochastic frontier model with a risk and an inefficiency function. The results reveal that feed, labor, and capital have positive and significant impacts on production. In addition, an increased fingerling density and a larger farm increase the risk, whereas the use of feed and the capital invested have the opposite effect. Access to extension services has a positive effect and increases farm efficiency. An investigation of the farm size–productivity inverse relationship reveals that this phenomenon is not applicable to Bangladesh aquaculture. In general, efficient farmers are large‐scale farmers, who use a lower stocking density but a higher feeding intensity, resulting in a higher yield. On average, farmers use less labor and feed than what is optimal. To increase efficiency and reduce risk, it is recommended that more technical knowledge on optimal input use, extension service, and capital is made available to aquaculture farmers.     

Development of aquaculture financial planning system

Abstract

Economically efficient feeding levels in intensively stocked ponds might be below minimum biological feeding requirements under adverse market conditions. A catfish production function that estimated relationships between yield and stocking and feeding rates was used as the basis for estimating production relationships. Feed price boundaries were developed that allowed the feeding rate to exceed the minimum biological level but still reflected economically efficient rates over a range of catfish prices and producer risk preferences. At higher stocking densities (20,000/ha), the feed price upper bound is lower than at lower stocking densities. Producers stocking at higher rates will be less likely to maximize profit and meet minimum biological feeding requirements as feed price increases than those producers stocking at lower rates. However, if feed prices exceed the upper bounds calculated in this paper, producers should engage in feeding only at levels necessary to meet farm financial and cash flow obligations until such time as the feed price decreases.     

Effects of Stocking Sac-Fry and Hatchery-Fed Fry on Production of Fingerling Channel Catfish Ictalurus punctatus

Abstract.— Channel catfish Ictalurus punctatus fry are typically held under hatchery conditions for 7 to 14 d after hatching to allow feeding and growth before they are stocked into nursery ponds to produce fingerling catfish. In an attempt to reduce hatchery operating costs, several catfish fingerling producers in Louisiana presently stock fry within 2 d after hatching before yolk absorption is complete. Fry at this stage of development are commonly referred to as "sac-fry." Although research has shown that fry can be stocked at the onset of yolk absorption with no detrimental effects on subsequent fingerling production, stocking sac-fry has been reported to result in reduced fingerling survival. To further investigate this topic, production trials were conducted in experimental outdoor pools over the course of two growing seasons to evaluate the effect of stocking fry of three different ages (2-, 7-, and 14-d post-hatch, DPH) on survival, growth (weight and length), condition factor (K), yield, feed consumption, and feed conversion ratio (FCR) of fingerling catfish. Results from both trials indicated that the age at which fry were stocked had no effect on production characteristics with the exception of growth. Specifically, fingerlings reared from fry stocked at 2 and 7 DPH were significantly larger than fingerlings reared from fry stocked at an age of 14 DPH. These findings suggest that the practice of stocking sac-fry may be a suitable alternative to the traditional procedure of holding and feeding fry under hatchery conditions prior to stocking. However, in order to fully evaluate the effects of early-age stocking of catfish fry on fingerling production, additional studies must be conducted under pond conditions. Furthermore, these studies must be coupled with a rigorous economic analysis before the practice of stocking sac-fry can be recommended to the catfish industry.     

Reducing Catfish Farm Losses Due to Dockages Assessed by Processing Plants

Dockages can have a significant effect on catfish, Ictalurus punctatus, farm revenues. This study was conducted to quantify common dockages, examine seasonal and yearly variations in dockages assessed, and determine optimal production practices given various dockage scenarios. A convenience survey of invoice records from 30 commercial catfish farms and 10 processing plants provided 3686 daily catfish load records that were used to quantify dockages. A linear programming model was developed to examine optimal production practices given 11 alternative production scenarios with five size‐grading technologies subject to 24 types and levels of dockages. The survey revealed that 95% of catfish loads delivered to processing plants between 1997 and 2002 were assessed dockages that resulted in average losses of 2.45% per load or $0.066/kg of catfish marketed over the study period. Out‐of‐size discounts constituted the greatest losses. Dockage losses can be reduced by shifting either to longer‐term single‐batch production or more intensive grading. Longer‐term production results in fewer smaller fish that would incur dockage losses. However, cash flow constraints require more intensive early‐season grading. The grader choice depended on the dockage tolerance level and rate, the frequency distribution of sizes of catfish in the population, the efficiency of the grading technology, and the cost of the grading method. Larger farms minimize losses with intensive active grading (University of Arkansas at Pine Bluff grader).     

Temporary Sequestration of Fingerling Channel Catfish in Cages as a Means to Improve Production of Multiple-Crop Ponds

Abstract

Two studies were conducted to determine if temporary sequestration of fingerling channel catfish, Ictalurus punctatus, in cages improves production of multiple-crop ponds. In the first study, 0.04-ha ponds were stocked with 295 large (mean weight = 566 g) and 780 fingerling (mean weight = 21 g) catfish. Fingerlings were stocked into cages or open ponds. At 120 days after stocking, fish in cages were released. After an additional 40 days, ponds were clean-harvested to remove large (>500 g) and small (<500 g) fish. In the second study, ponds (0.08-ha) were stocked with 750 large (mean weight = 46 g) and 750 small (mean weight = 20 g) fingerling catfish. Small fingerlings were stocked into cages or open ponds. At 60 days after stocking, fish in cages were released. Market-ready fish were selectively harvested at five and nine months after stocking. Results from the first study indicated that individual weight, weight gain, and yield of both size classes of fish raised in sequestered ponds were significantly greater (P< 0.05) than that of fish raised in open ponds. In addition, total weight gain and yield of fish in sequestered ponds was significantly greater (P< 0.05) than those in non-sequestered ponds. Results from the second study indicated that a significantly greater (P< 0.05) number of market-ready fish were harvested from sequestered ponds than from non-sequestered ponds. Mean yield of sequestered ponds was 31% greater than that of non-sequestered ponds; however, differences were not significant (P> 0.05). Amount of feed fed to fish raised in sequestered ponds was significantly greater (P< 0.05) than amount of feed fed to fish raised in non-sequestered ponds in both studies. It is unclear which factor or factors were responsible for the enhanced production of sequestered ponds; however, temporary sequestration may reduce agonistic behavior and competition for feed between fish size groups.     

Cage culture of sutchi catfish, Pangasius sutchi (Fowler 1937): effects of stocking density on growth, survival, yield and farm profitability

The sutchi catfish, Pangasius sutchi (Fowler 1937) was grown at 10 stocking densities in cages suspended in a river‐fed channel during the summer of 2000. Catfish fingerlings (mean length 9.1–9.7 cm and mean weight 5.9–6.7 g) were stocked at densities of 60, 70, 80, 90, 100, 110, 120, 130, 140 and 150 fish m^?3. After 150 days, growth and yield parameters were studied and a simple economic analysis was carried out to calculate profitability. The mean gross yield ranged from 15.6±0.27 to 34.5±0.44 kg m^?3 and the net yield ranged from 15.2±0.22 to 33.5±0.36 kg m^?3 and showed significant variations (P<0.05). The mean weights of fish at harvest were inversely related to stocking density. Both gross and net yields were significantly different and were directly influenced by stocking density but the specific growth rate, survival rate and feed conversion rate were unaffected. Higher stocking density resulted in higher yield per unit of production cost and lower cost per unit of yield. The net revenue increased positively with increasing stocking density. A density of 150 fish m^?3 produced the best production and farm economics among the densities tested in this experiment.     

Prolonged Culture Period on Production Cost and Factor Input: A Case from the Pacific Oyster,Crassostrea gigas,Farming Industry in Yunlin County,Taiwan

The Yunlin coastal area is the largest oyster culture in Taiwan; however, the oyster farmers reported the negative impact of a prolonged oyster culture period and an increased operating cost in 2010. This study uses the translog cost function to consider the possibility of an oyster culture period extension to estimate oyster cost elasticity, own‐price elasticities, and cross‐price (substitution) elasticities, to evaluate whether the oyster farming industry in Yunlin County has economies of scale, and to assess the relationship with a substitution of inputs. We found that the Yunlin oyster culture has economies of scale, and that the oyster farmers can expand production scale to reduce costs. The own‐price elasticities of demand for inputs are less than 1, indicating fairly inelastic factor demands in oyster production. The oyster farming industry displays strong substitutability between the prolonged culture period and capital input, suggesting that the oyster farming industry is more responsive to a higher prolonged culture period cost, in terms of capital input.