The Upper Midwest Environment Sciences Center has conducted several efficacy trials to control mortality associated with fungal infections on fish and fish eggs, in each instance the organism was Saprolegnia sp. In this study, the naturally occurring pathogen was identified as S. parasitica. Our findings agree with fungal identification reported in the literature, in which the family Saprolegniaceae (which includes the genera Saprolegnia, Achlya, Aphanomyces and Dictyuchus) is the major cause of saprolegniasis in aquaculture production Alderman and Polglase, 1984 and Bruno and Wood, 1999.
This study was designed to evaluate in an actual hatchery production situation the efficacy of hydrogen peroxide treatments to control mortality and improve egg hatch of channel catfish eggs infected with fungus. Therapeutic treatments administered under hatchery conditions have a greater chance of encountering variability in biological and physical parameters compared to chemical treatments administered under standardized laboratory test conditions. Rach et al. (1997) emphasized the need to verify chemical treatment regimens and documented potential factors that could result in lower treatment concentrations in egg jars. Verifying treatment concentrations in this study identified the lower than expected hydrogen peroxide concentrations and highlighted the differences in accuracy of chemical delivery systems (IV bottle or peristaltic pump). The lowest treatment concentrations were recorded on the first treatment day when IV bottles were used to administer the chemical. In Trial 1, the IV bottle system delivered mean hydrogen peroxide concentrations that were 70% of the nominal value, whereas the peristaltic pump system delivered 85% of the expected concentration.
The Upper Midwest Environment Sciences Center has conducted several efficacy trials to control mortality associated with fungal infections on fish and fish eggs, in each instance the organism was Saprolegnia sp. In this study, the naturally occurring pathogen was identified as S. parasitica. Our findings agree with fungal identification reported in the literature, in which the family Saprolegniaceae (which includes the genera Saprolegnia, Achlya, Aphanomyces and Dictyuchus) is the major cause of saprolegniasis in aquaculture production Alderman and Polglase, 1984 and Bruno and Wood, 1999.
This study was designed to evaluate in an actual hatchery production situation the efficacy of hydrogen peroxide treatments to control mortality and improve egg hatch of channel catfish eggs infected with fungus. Therapeutic treatments administered under hatchery conditions have a greater chance of encountering variability in biological and physical parameters compared to chemical treatments administered under standardized laboratory test conditions. Rach et al. (1997) emphasized the need to verify chemical treatment regimens and documented potential factors that could result in lower treatment concentrations in egg jars. Verifying treatment concentrations in this study identified the lower than expected hydrogen peroxide concentrations and highlighted the differences in accuracy of chemical delivery systems (IV bottle or peristaltic pump). The lowest treatment concentrations were recorded on the first treatment day when IV bottles were used to administer the chemical. In Trial 1, the IV bottle system delivered mean hydrogen peroxide concentrations that were 70% of the nominal value, whereas the peristaltic pump system delivered 85% of the expected concentration.
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