Grant: Discovery Grants Program - Individual

Aquaculture has expanded globally with an increase not only in absolute production (kilotons/year) but also in the number of fish species being cultured in both fresh water and marine ecosystems. The majority of fish protein consumed worldwide is now aquacultured. Infectious disease greatly impacts production in terms of increased morbidity, mortality, and antibiotic use, while decreasing animal welfare and aquaculture's social license. Tenacibaculosis, caused by an infection of Tenacibaculum bacteria, is a term used for several regional clinical presentations of this highly costly disease in marine fish. Understanding the fundamental basis of disease is critical for improving disease management and mitigation in aquaculture. My research program is aimed at better understanding the development of tenacibaculosis in fish and how bacteria are influenced by the environment and host species. Tenacibaculum and other commensal and opportunistic pathogens are present within the mucosal microbial communities of the skin, gills and intestine of marine fish. Environment, host species immune response and disease conditions can influence the microhabitats for mucosal microbial communities by stabilizing or destabilizing, mutually beneficial host-microbe interactions. Shifts in the number of bacteria within the microbiota (dysbiosis) for any reason may lead to dominance of opportunistic bacteria that may compromise fish health. The basis of my research is to use an in vivo infection model to investigate how salmon microbiomes and salmon immune responses, are modified by Tenacibaculum infections, and how critical environmental stressors like salinity and temperature alter microbial communities and influence Tenacibaculum gene expression during an infection. Understanding the interactions between host immune responses and microbiota can lead to identifying phenotypes of fish resistant to disease and identify large sets of Tenacibaculum gene functions that will constitute a foundation for future studies, such as vaccine development and novel or alternative antimicrobials and other therapeutics.