Ecology of Infectious and Parasitic Diseases in Populations of Wild Fish

Unlike traditional fish health research, which has focused primarily on the identification, treatment, and prevention of diseases in hatchery and cultured fishes, research in the field of disease ecology typically involves understanding, forecasting, and mitigating the detrimental impacts of diseases on wild populations.  Historically, the few investigations involving infectious and parasitic diseases in wild fishes have been limited primarily to periodic pathogen prevalence surveys and pathological responses to epizootic fish kills.  These approaches, although valuable for identifying pathogens of concern and documenting some population-level  impacts of disease epizootics, are largely ineffective at determining sub-epizootic effects of diseases, understanding environmental  conditions that preface diseases, or mitigating disease impacts on wild populations.   However, new insights into the ecology of diseases in wild fish populations have recently been realized using novel approaches that combine methodologies and principles from traditional fish health, pathology, molecular biology, epidemiology, population biology, and specific etiological disciplines (ie. virology, bacteriology, parasitology) with well-controlled empirical studies that ascribe cause-and effect disease relationships between host, pathogen, and environmental variables.  This symposium highlights some of the recent advancements in disease ecology of wild fishes by providing case histories where this research approach has been effective.  The intent of this symposium is to demonstrate the utility of disease ecology research for understanding temporal and spatial fluctuations in population sizes and demographics that are typically veiled within the natural mortality constant (M) of fishery population models.