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Energy and imported trout egg subsidies hold a pivotal role for Iranian trout farms. They aim to decrease production costs, yet their impact on the profit efficiency of farms remains dubious. The first objective of this paper is to assess how the current subsidy scheme affects the profit efficiency of hatchery and propagation trout farms in Mazandaran, Iran. We examine several subsidy reform scenarios to enhance profit efficiency as a second objective. Standard profit efficiency (SPE) is used to acquire the efficiency of the trout farms using data envelopment analysis. Results show that the majority of farms are inefficient and highly dependent on subsidies. Comparing farms with high efficiency against those with low efficiency as a third aim of research highlights the importance of farms holding a propagation license, engaging in vertical integration, achieving adult trout production surpassing 81 t, and maintaining a fish total feed consumption to trout production ratio below 0.74. Findings from reformation scenarios reveal 1) redirecting the current subsidy towards purchasing the extruder machines for fish feed production, 2) transferring funds to subsidize electricity based on the farm's electricity consumption, and 3) opting for the production of genetically modified eggs gives higher SPE. Reformation can also reduce the burden on public funds and dependency on importation. • Hatchery and propagation of Iranian trout farms are heavily dependent on subsidies. • The allocation of subsidies leads to enhanced standard profit efficiency (SPE). • Removing electricity and trout egg import subsidies notably reduces SPE compared to diesel fuel subsidy elimination. • Introducing reform options to modify the current subsidy regime could improve SPE. • Funding extruder machines, paying trout farms for electricity, and using genetically modified eggs all boost SPE. [ABSTRACT FROM AUTHOR]

Background and Objectives: In Iran, rainbow trout farms exist in almost all provinces. Viral hemorrhagic septicemia is one of the most important infectious diseases of the rainbow trout which is a serious threat to the farming industry. This study was conducted to investigate outbreaks in 2014 and identify important determinants of the agent entry and disease occurrence in the farms. Methods: Data were collected using a structured questionnaire and the disease was detected based on clinical signs and laboratory investigations by PCR methods. Results: During 52 weeks of the study in 2014, 114 of 1140 (12.63%) farms were affected within 78 zones in 14 provinces. In multivariable analysis, illegal entrance of fries (odds ratio: 7.81, 95% CI: 3.63-16.8), illegal entrance of fish (odds ratio: 5.60, 95% CI: 3.03-10.35) and use of river as the water supply (odds ratio: 2.46, 95% CI: 1.51-4.02) were detected as risk factors associated with virus entry and disease outbreak in farms. Conclusion: Observing biosecurity measures in the farm level, applying risk-based surveillance based on known risk factors, and assessing these factors on a regular basis are important in prevention and control of VHS.

Three trout farms from Nepal were studied to investigate the changes in physico-chemical parameters and their potential threat to natural water bodies receiving the effluents. Reference and impact sites were determined in each farm so as to find out the level of impacts due to farming activities. Some of the parameters such as dissolved oxygen, turbidity, conductivity, and total dissolve solids were significantly changed in the impacted zones compared to reference sites. Similarly, concentrations of some major ions such as calcium and sodium were increased in the impacted zones. On the other hand, some of the parameters such as pH and potassium did not change in the impacted zone although their concentrations were different among farms studied. Nevertheless, the overall changes in the physico-chemical parameters did not pose health risk to the aquatic ecosystems receiving effluents from these fish farms as the concentrations were below the prescribed levels by Environmental Protection Agency (EPA) as well as Nepal Environment Statistics. This is an indication that, although fish farming activities are degrading water qualities, there is no threat to the water quality receiving the effluents yet probably due to small scale farming. The increase in number of fish farms in the same area, however might pose risk to the ecological health in the region which warrants regular monitoring. INTERNATIONAL JOURNAL OF ENVIRONMENTVolume-6, Issue-2, Mar-May 2017, Page: 43-55

The ability of Flavobacterium psychrophilum to adhere to and form biofilms on different types of materials used on rainbow trout (Oncorhynchus mykiss) farms was evaluated in this study. F. psychrophilum NCIMB 1947T, was inoculated onto a variety of different surfaces, including stainless steel, plastic, glass, wood, and zinc pyrithione encapsulated antibacterial plastic. The samples were then cultured in a humidified chamber or transferred into fish tanks containing either (1) freshwater or (2) filtered lake water. The formation of biofilms was quantified by fluorescent microscopy. F. psychrophilum formed biofilms on all of the surfaces tested; however, the adherence of the bacterium to the antibacterial plastic was much lower than the attachment observed on the other surfaces, illustrating the bacteriostatic properties of this material for F. psychrophilum. Moreover, bacterial numbers were greater on the surfaces maintained in lake water compared with those maintained in freshwater. The mineral composition of the lake water may have been responsible for the increased bacterial adherence observed between the two types of water. Treatment of the water, regular cleaning of equipment and the use of antimicrobial material to house the fish may help reduce biofilm formation by F. psychrophilum in fish farming systems. [ABSTRACT FROM AUTHOR]