Ultraviolet light differentially reduces viability of fish- and fish farm-associated flavobacteria (families Flavobacteriaceae and Weeksellaceae)

Authors: KNUPP, CHRISTOPHER - Michigan State University; FAISAL, MOHAMED - Michigan State University; BRENDEN, TRAVIS - Michigan State University; SOTO, ESTEBAN - University Of California, Davis; Lafrentz, Benjamin; GRIFFINS, MATT - Mississippi State University; Wiens, Gregory; CAVENDER, WADE - Utah Division Of Wildlife Resources; VAN VLIET, DANIELLE - Utah Division Of Wildlife Resources; LOCH, THOMAS - Michigan State University

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2023
Publication Date: 9/30/2023
Citation: Knupp, C., Faisal, M., Brenden, T., Soto, E., Lafrentz, B.R., Griffins, M.J., Wiens, G.D., Cavender, W., Van Vliet, D., Loch, T. 2023. Ultraviolet light differentially reduces viability of fish- and fish farm-associated flavobacteria (families Flavobacteriaceae and Weeksellaceae). North American Journal of Aquaculture. 85(4)311-323. https://doi.org/10.1002/naaq.10300.
DOI: https://doi.org/10.1002/naaq.10300

Interpretive Summary: Flavobacteria, including Flavobacterium and Chryseobacterium species, are significant contributors to disease-related losses in aquaculture worldwide. These bacteria often enter fish farms and hatcheries through source water, posing a persistent challenge for disease management. While ultraviolet (UV) light treatment is commonly used to disinfect water and has proven effective against various pathogens, its effectiveness in inactivating flavobacteria remains largely unexplored. This study aimed to evaluate how well UV treatment reduces the viability of fish-pathogenic and fish-associated flavobacteria in their free-floating (planktonic) form. The findings of this research could help improve biosecurity measures in aquaculture by optimizing UV treatment protocols to mitigate the risks posed by these bacterial infections.

Technical Abstract: Globally, flavobacteria (family Flavobacteriaceae and Weeksellaceae) are leading causes of disease-related losses in fish-farms and hatcheries. One route flavobacteria gain access to aquaculture facilities is via source water. Ultraviolet (UV) light treatment of source water has been effective in reducing the risk of disease outbreaks caused by nonflavobacteria; however, the UV dose required to inactivate flavobacteria has been understudied. The primary objective of this study was to examine the efficacy of UV light treatments for reducing the viability of fish-pathogenic and fish-associated Flavobacterium and Chryseobacterium species in a planktonic form.