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Economics is the study of the allocation of scarce resources to meet human wants and needs and has a critical role to play in addressing challenges related to environmental sustainability, community resilience, and food security. In the context of aquaculture, the key to such a discussion is understanding the linkages of aquaculture farming businesses with other economic sectors and how policy decisions that affect aquaculture result in economic ripples throughout local, regional, and national economies. The only previous national estimates of the economic contributions of U.S. aquaculture are nearly 30 years old. The current study was based on comprehensive data from detailed farm‐level surveys (that captured 77% of the total value of U.S. aquaculture) supplemented by information from publications on the remaining aquaculture sectors. The economic contributions measured in this study were limited to those at the farm level and do not include subsequent impacts that occur as farmed products move through processing, distribution, food service, and retail sectors in the U.S. economy. Results showed that U.S. aquaculture farms contributed $4 billion annually and supported more than 22,000 jobs each year. Labor income and value‐added contributions were $1 billion and $3 billion, respectively. Analysis of the linkages of U.S. aquaculture production activities with other economic sectors showed that nearly all (96%) economic sectors were supported to some degree by U.S. aquaculture farms. Foodfish farms generated the greatest contributions, followed by mollusk farms. Freshwater aquaculture farms contributed twice that of the contributions of marine aquaculture because of the greater size of the freshwater aquaculture sector. Growth of both freshwater and marine sectors would increase overall contributions to the economy. Constraints to growth of aquaculture include regulatory barriers that have restricted existing sectors from meeting current demand for their products. The lack of an adequate regulatory framework for offshore marine aquaculture has constrained its growth and development, especially with respect to the rest of the world. Streamlined regulations implemented in a more timely and efficient manner could result in substantially greater economic contributions from existing U.S. aquaculture farms. The total economic impact of U.S. aquaculture production is likely three to four times greater than the farm‐level impacts estimated in this study as a result of impacts that occur as aquaculture products move downstream through various marketing channels. Additional research is needed to measure the impacts of U.S. aquaculture products in the processing, distribution, food service, supermarket, and restaurant levels of the marketing chain to fully capture the total economic contributions from U.S. aquaculture. [ABSTRACT FROM AUTHOR]

Edwardsiellosis of catfish caused by Edwardsiella ictaluri and Edwardsiella piscicida remains one of the most significant diseases in U.S. catfish aquaculture. Economic losses related to this disease are currently unknown. This work sheds light on the losses associated with E. ictaluri and E. piscicida in catfish aquaculture. The robust economic approach employed is grounded in farm-level production data and long-term disease trends in the industry. Direct farm-level economic losses from Edwardsiellosis ranged from −$3,485 to −$13,320/ha causing industrywide economic losses of −$5.2 to −$17.6 million/year. The lost revenue due to Edwardsiellosis ranged from −$8.4 to −$24.8 million/year causing a negative economic impact of −$15.5 to −$45.9 million/year. The economic losses and negative impacts of Edwardsiellosis are relatively greater on the foodfish sector compared to the fingerling sector. This work provides a platform for a more accurate estimation of the true economic impacts of diseases for aquaculture sectors for which commercial farm data is available. [ABSTRACT FROM AUTHOR]

The U.S. catfish industry has adopted several production practices which embody varying degrees of economic risk. Employing commercial farm data, this study quantified the economic risks associated with six catfish food fish production strategies. Stochastic Monte Carlo simulations employing established enterprise budgets found fish yield, feed price, and feed conversion ratio contributing highly to variations in the cost of production. While multiple-batch (MB) farming of channel catfish was the least risky strategy, both MB and intensively aerated production were stochastically dominant (second-order) to low-intensity single-batch production. Split-pond and intensively aerated hybrid catfish production demonstrated consistently lower production costs and were stochastically dominant (second-order) to medium-intensity single-batch production. Multiple-batch and intensively aerated production of channel catfish were more susceptible to price (market) risk while hybrid catfish production was more susceptible to yield (production) risks. First order stochastic dominance of split-pond technology on larger farms as compared to low-intensity culture on smaller farms suggested that yield increasing intensive production practices supersede low-intensity technologies and help achieve economies of scale. Study results provide critical information on the relative risk associated with different catfish production strategies under varying economic and market conditions. [ABSTRACT FROM AUTHOR]

The catfish industry is the largest U.S. aquaculture sector and a major contributor to the rural economies of the Southern states of Alabama, Arkansas, and Mississippi. Economic contributions of this industry to the tristate region were estimated using an input-output modeling approach with the IMPLAN database and software (Impact Analysis for Planning MIG, Inc.). An analysis-by-parts approach was employed as the IMPLAN database does not disaggregate the catfish sector from other livestock industries which have expenditure patterns that differ substantially from those of catfish. All major actors of the catfish industry, i.e. feed mills, hatcheries, foodfish farms, and processing plants, were surveyed to obtain their expenditure patterns and output in terms of sales. Data were obtained from 68 farms (hatcheries and foodfish combined), four feed mills, and eight processing plants in the tristate region. Sales and expenditure values were converted to coefficients employing standard enterprise budgeting techniques and imported to the IMPLAN model for estimating industry contributions during 2019. The direct output from the catfish industry ($1.10 billion) generated a total economic contribution of $1.91 billion. The industry directly employed 4,298 people and created an additional 4,868 jobs in the tristate economy for a total employment effect of 9,166 jobs. Catfish industry spending created an indirect economic effect of $552 million in other secondary sectors that supplied production inputs and services. The induced economic effect generated from household spending amounted to $254 million. Some of the key sectors influenced by the catfish industry were grain farming, banking and financial institutions, truck transportation services, electricity generation, equipment, and machinery manufacturing. The industry also generated $78 million in local, state, and federal taxes. This study provides critical insights for policymakers and others into the contribution of the U.S. farm-raised catfish industry to local and regional economies as well as its diverse-industry interconnections. [ABSTRACT FROM AUTHOR]

The U.S. catfish industry is evolving by adopting intensive farming practices such as intensively aerated ponds and split-pond systems. The functional relationship between fish yield and key production inputs in these intensive systems was analyzed based on commercial catfish production data from 143 pond observations (2010−2018). A Cobb-Douglas production function was employed for the intensively aerated ponds and a modified translog production function was used to define the production relationships in split ponds. Results indicated that the size of fingerlings at stocking, stocking density, aeration rate, feeding rate, survival, and harvest size of the fish were statistically significant variables influencing fish production in intensively aerated ponds. Initial fingerling stocking biomass (interaction of stocking size and stocking density), feed conversion ratio (FCR), feeding rate, and pond size were the most important variables influencing production in split-pond systems. Feed fed, as well as stocking biomass, were the significant variables found in both models. Both production functions indicated further scope for improvement in the use of inputs to increase production, especially in feed management. [ABSTRACT FROM AUTHOR]

The catfish industry is integral to the economy of the southern United States contributing >70% of the total U. S. finfish production. Intensive catfish production systems are more vulnerable to infectious disease outbreaks resulting in significant economic losses. Viruses are a major concern especially in the hatchery and nursery phases of catfish rearing. These infectious agents require host cell machineries to replicate. The ability to propagate fish viruses in vitro using cell cultures is imperative in advancing virus research and facilitating disease management strategies. Several viruses show host‐ or even tissue‐specificity. Scarcity of host‐specific fish cell lines forces researchers to rely on general cell lines that might not be conducive for the replication of some viruses, thus hindering their isolation, identification, and characterization. The ictalurid cell line (channel catfish ovary [CCO‐ATCC® CRL‐2772]) previously available from cell repository (ATCC) has recently been reported as cross‐contaminated by brown bullhead (BB) cells. Lack of host‐specific cell cultures and contamination issues necessitated initiation of cell cultures from the fin tissues of hybrid catfish (♀ channel catfish × ♂ blue catfish). A combination approach involving tissue explantation and enzymatic digestion methods were used to develop catfish fin cell cultures. These cultures were passaged over 100 times and transitioned into an established cell line. The hybrid catfish fin (HCF) cell line was characterized, growth conditions optimized, species of origin molecularly authenticated, and the susceptibility to fish viruses evaluated. This catfish cell line could serve as an efficient tool for virus studies, antiviral agent screening, and vaccine development benefitting catfish aquaculture. [ABSTRACT FROM AUTHOR]

Intensive aquaculture production systems often encounter infectious viral disease outbreaks causing substantial fish mortalities and associated economic losses. Blue catfish alloherpesvirus (BCAHV) is an Ictalurid herpesvirus with limited information on pathogenesis. To determine the host‐specificity and potential host range of BCAHV, the virus was inoculated onto various fish cell lines belonging to families Ictaluridae, Cyprinidae, Centrarchidae, and Clariidae. Viral replication and exhibition of cytopathic effects (CPEs) were restricted to cell lines from the family Ictaluridae indicating the host preference of BCAHV. Subsequently, fish challenges were conducted to evaluate intrinsic and extrinsic factors influencing BCAHV infection. Mortality because of BCAHV infection was significantly higher in blue catfish and least in channel catfish further specifying the host preference of the virus. Histopathological assessment of the BCAHV infected fish revealed splenitis with severe erythrophagia. Host susceptibility to BCAHV differed with age with fish at 60 days post hatch being more susceptible. Temperature had a significant role in the activation and pathogenesis of BCAHV. Fish exposed to BCAHV at a sustained high temperature had significantly low mortality suggesting the likelihood of virus inactivation. Virus exposure in tanks with high stocking density resulted in significantly high fish mortalities indicating horizontal transmission is a key element in BCAHV pathogenesis. The heightened pathogenicity of BCAHV in blue and hybrid catfish as observed in this study validates its potential to be a significant pathogen in catfish production. [ABSTRACT FROM AUTHOR]