Terrill R. Hanson

Management of Off-Flavors in Pond-Cultured Channel Catfish with Weekly Applications of Copper Sulfate

Abstract Eighteen 0.4-ha earthen ponds in northwest Mississippi were used in a 3-year study to evaluate the effect of weekly copper sulfate applications on the incidence and economic impact of environment-induced off-flavors in channel catfish Ictalurus punctatus. Each spring, when water temperatures increased above 20°C, nine ponds were treated weekly with 0.12 mg Cu/L. Treatments were discontinued each fall when water temperatures fell below 20°C. Overall prevalence of off-flavor was reduced by 80% for ponds treated with copper sulfate compared with control ponds, and episodes of off-flavor were of shorter duration in treated ponds. Off-flavors never delayed fish harvest from treated ponds, whereas off-flavors delayed fish harvest on 10 occasions in control ponds. Average annual fish harvest was 5,900 kg/ha from ponds treated with copper sulfate and 5,349 kg/ha from control ponds. The 9% reduction in fish harvest from control ponds was due to infectious disease outbreaks in one or two ponds each year wh...

Farm-Level Economic Impacts of Bolbophorus Infections of Channel Catfish

Abstract The prevalence of infections by trematodes Bolbophorus sp. in populations of pond-raised channel catfish Ictalurus punctatus was determined by sampling 64 ponds on a farm in northwestern Mississippi. Of the 40 food fish ponds sampled, 23 (58%) contained trematode-infected fish; 7 pond populations were categorized as having light infections (1–33% infection rates), 5 as having moderate infections (34–66% infection rates), and 11 as having severe infections (≥67% infection rates). Only 3 of the 24 fingerling ponds contained fish infected with Bolbophorus trematodes, and the infection rates were light. Feed consumption and estimated fish production in food fish ponds differed significantly among the four categories of within-population infection rate, and feed consumption and fish production decreased as infection rates increased. Relative to the production in uninfected populations, estimated fish production was reduced by 14, 35, and 40% in populations with light, moderate, and severe infections, ...

A translog demand model for inherited traits in aquacultured catfish

Abstract Manipulation of physical traits of catfish body form has the potential to change the relative quantities of different final product forms. Some of these forms will have higher value to consumers, resulting in higher profits for producers. Advances in genetic research will allow more effective manipulation of physical traits of aquacultured catfish in orderto increase relative quantities of desirable product forms. To identify which product forms hold the most potential value to consumers, we use the indirect Translog demand system to estimate welfare effects from substitution among various forms of fresh catfish.

Identifying Risk Factors Affecting Weather- and Disease-Related Losses in the U.S. Farm-Raised Catfish Industry

Two double-limit tobit models are used to identify significant risk factors that most affect farm-raised catfish losses from weather-related events and from disease outbreaks. Results of the weather loss model indicate that the variables for operator education level, number of ponds, pond water depth, production management strategy, past experience with severe losses from low oxygen levels from off-farm power outages, past experience with severe losses from diseases, and being in the South are statistically significant. Results of the disease loss model indicate that the variables for operator experience and pond water depth are significant. Development of models explaining weather and disease losses through observable variables provides a better understanding of the interrelation between the loss perils and explanatory variables so management strategies can be developed to mitigate losses from identified risk factors.

Management of Musty Off-Flavor in Channel Catfish from Commercial Ponds with Weekly Applications of Copper Sulfate

Abstract We evaluated the effectiveness of weekly low-dose applications of copper sulfate (0.12 mg of Cu/L of water) for reducing the prevalence of off-flavor in channel catfish Ictalurus punctatus on commercial farms. The study was conducted over 3 years in ponds (3.2–8.4 ha) on two catfish farms in western Mississippi. Farm managers applied copper sulfate (0.5 mg of copper sulfate pentahydrate/L of water) weekly beginning in the late spring or early summer and continued until the water temperature dropped below 20°C. Water samples were collected from treated and untreated ponds approximately every 3 weeks during the application period and were monitored for levels of the musty compound 2-methylisoborneol (MIB), chlorophyll a, and phytoplankton community structure and abundance. In addition, channel catfish were caught from each study pond during the third year of the study and were checked for flavor. Levels of MIB and the abundance of the MIB-producing cyanobacterium Oscillatoria perornata were signifi...

Economic Impact of the Farm-Raised Catfish Industry on the Mississippi State Economy

Abstract The Mississippi catfish industry began in the late 1960s and early 1970s. Employment, income, and investment stemming from the growth of the farm-raised catfish industry have been, and continue to be, critical to the economic development of delta and eastern regions of Mississippi. Estimates of total investment in catfish feed mills, farms, and processing plants were estimated to range from

Evaluation of a Fingerling-to-Stocker Phase as Part of a New Production Strategy for the Commercial Farming of Channel Catfish

600 to

Economic analysis of overwinter feeding regimens for channel catfish (Ictalurus punctatus)

700 million. Farm-gate sales of catfish were

Production and Associated Economics of Channel Catfish Fed Different Practical Diets in the Fingerling–Stocker Phase of Culture

260 million in 2001. Direct effects of the Mississippi farm-raised catfish industry were estimated using primary and secondary data for the industry and indirect and induced effects were estimated using an IMPLAN input-output model using 2000 Mississippi data. The total impact (direct, indirect, and induced) of the Mississippi farm-raised catfish industry was estimated to be 10,760 employees,

Agricultural Insurance as an Environmental Policy Tool

208.25 million in income, and